MTS 318 User Manual

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318 Load Unit Product Information

Model 318.10 Model 318.25 Model 318.50

100-183-837 B

Trademark information MTS is a registered trademark of MTS Systems Corporation within the United

States. This trademark may be protected in other countries.

Molykote is a registered trademark of Dow Chemical Corporation. All other trademarks or service marks are property of their respective owners.

Publication information

MANUAL PART NUMBER PUBLICATION DATE

100-183-837 A June 2007

100-183-837 B April 2009

Contents

Technical Support 7

How to Get Technical Support 7

Before You Contact MTS 7

If You Contact MTS by Phone 9

Problem Submittal Form in MTS Manuals 10

Preface 11

Before You Begin 11

Conventions 12

Documentation Conventions 12

Introduction 15

Load Unit: Overview 15

318 Load Unit: Component Identification 17

318 Load Unit: Component Description 18

318 Load Unit: Specifications 20

Series 661 Force Transducer: Specifications 24

318 Load Unit: Dimensions 26

Safety 33

General Safety Practices 33

Safety Practices Before System Operation 34

Safety Practices While the System Is in Operation 39

Hazard Icons 41

318 Load Unit: Hazard Labels 42

318 Load Unit: Crush Point Hazards 45

318 Load Unit Contents

Installation 47

318 Load Unit: Unpack Upright Configuration 47

318 Load Unit: Unpack Horizontal Configuration 49

318 Load Unit: Connect Cables 54

318 Load Unit: Connect Hydraulics 56

318 Load Unit: Unlock the Crosshead 56

Operation 59

Load Unit: Operation Preface 59

318 Load Unit: Control Module 60

318 Load Unit: Crush Point Hazards 62

318 Load Unit: Specimen Installation 62

318 Load Unit: Position the Crosshead Hydraulically 65

318 Load Unit: Position the Crosshead Manually 66

318 Load Unit: Adjust the Grips’ Clamp Rate 69

318 Load Unit: Adjust the Grips’ Clamp Force 70

Maintenance 73

Routine Maintenance Overview Checklist 74

318 Load Unit: Maintenance Intervals 77

318 Load Unit: Daily Inspections 78

318 Load Unit: Clean the Columns 78

318 Load Unit: Prevent Rust 79

318 Load Unit: Maintain Airmount Pressures 80

318 Load Unit: Bleed the Hydraulic Lift Cylinders 81

318 Load Unit: Adjust the Hydraulic Locks 83

318 Load Unit: Lubricate the Crosshead Locking Bolts 86

318 Load Unit: Align the Force Transducer 87

111 Accumulator: Maintenance Overview 93

111 Accumulator: Check and Change Precharge Pressure 94

244 Actuator: Maintenance 98

298 HSM: Maintenance 98

252 Servovalve: Maintenance Overview 100

252 Servovalve: Replace the Filter Element 100

252 Servovalve: Adjust the Mechanical Null 102

Servohydraulic Load Frame Maintenance and Service Logs 107

Contents

318 Load Unit

8 Hours/Daily 108

40 Hours/Weekly 109

80 Hours/Biweekly 110

500 Hours: Crosshead and Frame 111

500 Hours: Actuator 112

500 Hours: HSM 113

500 Hours: Hoses and Cables 114

500 Hours: Overall Complete System 115

500 Hours: Grips 116

1000 Hours 117

2000 Hours: Annual Maintenance 118

318 Load Unit Contents

Contents

318 Load Unit

Technical Support

How to Get Technical Support

Start with your

manuals

Technical support

methods

MTS web site

www.mts.com

E-mail techsupport@mts.com

Telephone MTS Call Center 800-328-2255

Fax 952-937-4515

Technical support

outside the U.S.

The manuals supplied by MTS provide most of the information you need to use and maintain your equipment. If your equipment includes MTS software, look for online help and README files that contain additional product information.

If you cannot find answers to your technical questions from these sources, you can use the internet, e-mail, telephone, or fax to contact MTS for assistance.

MTS provides a full range of support services after your system is installed. If you have any questions about a system or product, contact MTS in one of the following ways.

The MTS web site gives you access to our technical support staff by means of a Technical Support link:

www.mts.com > Contact MTS > Service & Technical Support

Weekdays 7:00 A.M. to 5:00 P.M., Central Time

Please include “Technical Support” in the subject line.

For technical support outside the United States, contact your local sales and service office. For a list of worldwide sales and service locations and contact information, use the Global MTS link at the MTS web site:

www.mts.com > Global MTS > (choose your region in the right-hand column) > (choose the location closest to you)

Before You Contact MTS

MTS can help you more efficiently if you have the following information available when you contact us for support.

Know your site

number and system

number

318 Load Unit Technical Support

The site number contains your company number and identifies your equipment type (material testing, simulation, and so forth). The number is usually written on a label on your MTS equipment before the system leaves MTS. If you do not have or do not know your MTS site number, contact your MTS sales engineer.

Example site number: 571167

When you have more than one MTS system, the system job number identifies which system you are calling about. You can find your job number in the papers sent to you when you ordered your system.

Example system number: US1.42460

Know information from

prior technical

If you have contacted MTS about this problem before, we can recall your file. You will need to tell us the:

assistance

• MTS notification number

• Name of the person who helped you

Identify the problem Describe the problem you are experiencing and know the answers to the

following questions:

• How long and how often has the problem been occurring?

• Can you reproduce the problem?

• Were any hardware or software changes made to the system before the

problem started?

• What are the model numbers of the suspect equipment?

• What model controller are you using (if applicable)?

• What test configuration are you using?

Know relevant

computer information

Know relevant

software information

If you are experiencing a computer problem, have the following information available:

• Manufacturer’s name and model number

• Operating software type and service patch information

• Amount of system memory

• Amount of free space on the hard drive in which the application resides

• Current status of hard-drive fragmentation

• Connection status to a corporate network

For software application problems, have the following information available:

• The software application’s name, version number, build number, and if

available, software patch number. This information is displayed briefly when you launch the application, and can typically be found in the “About” selection in the “Help” menu.

• It is also helpful if the names of other non-MTS applications that are

running on your computer, such as anti-virus software, screen savers, keyboard enhancers, print spoolers, and so forth are known and available.

Technical Support

318 Load Unit

If You Contact MTS by Phone

Your call will be registered by a Call Center agent if you are calling within the United States or Canada. Before connecting you with a technical support specialist, the agent will ask you for your site number, name, company, company address, and the phone number where you can normally be reached.

If you are calling about an issue that has already been assigned a notification number, please provide that number. You will be assigned a unique notification number about any new issue.

Identify system type To assist the Call Center agent with connecting you to the most qualified

technical support specialist available, identify your system as one of the following types:

• Electromechanical materials test system

• Hydromechanical materials test system

• Vehicle test system

• Vehicle component test system

• Aero test system

Be prepared to

troubleshoot

Write down relevant

information

After you call MTS logs and tracks all calls to ensure that you receive assistance and that action

Prepare yourself for troubleshooting while on the phone:

• Call from a telephone when you are close to the system so that you can try

implementing suggestions made over the phone.

• Have the original operating and application software media available.

• If you are not familiar with all aspects of the equipment operation, have an

experienced user nearby to assist you.

Prepare yourself in case we need to call you back:

• Remember to ask for the notification number.

• Record the name of the person who helped you.

• Write down any specific instructions to be followed, such as data recording

or performance monitoring.

is taken regarding your problem or request. If you have questions about the status of your problem or have additional information to report, please contact MTS again and provide your original notification number.

318 Load Unit Technical Support

Problem Submittal Form in MTS Manuals

Use the Problem Submittal Form to communicate problems you are experiencing with your MTS software, hardware, manuals, or service which have not been resolved to your satisfaction through the technical support process. This form includes check boxes that allow you to indicate the urgency of your problem and your expectation of an acceptable response time. We guarantee a timely response—your feedback is important to us.

The Problem Submittal Form can be accessed:

• In the back of many MTS manuals (postage paid form to be mailed to MTS)

• www.mts.com > Contact Us > Problem Submittal Form (electronic form to

be e-mailed to MTS)

Technical Support

318 Load Unit

Preface

Before You Begin

Safety first! Before you attempt to use your MTS product or system, read and understand the

Safety manual and any other safety information provided with your system. Improper installation, operation, or maintenance of MTS equipment in your test facility can result in hazardous conditions that can cause severe personal injury or death and damage to your equipment and specimen. Again, read and understand the safety information provided with your system before you continue. It is very important that you remain aware of hazards that apply to your system.

Other MTS manuals In addition to this manual, you may receive additional MTS manuals in paper or

electronic form.

If you have purchased a test system, it may include an MTS System Documentation CD. This CD contains an electronic copy of the MTS manuals that pertain to your test system, including hydraulic and mechanical component manuals, assembly drawings and parts lists, and operation and preventive maintenance manuals. Controller and application software manuals are typically included on the software CD distribution disc(s).

318 Load Unit Preface

Conventions

DANGER

WARNING

CAUTION

Conventions

Documentation Conventions

The following paragraphs describe some of the conventions that are used in your MTS manuals.

Hazard conventions As necessary, hazard notices may be embedded in this manual. These notices

contain safety information that is specific to the task to be performed. Hazard notices immediately precede the step or procedure that may lead to an associated hazard. Read all hazard notices carefully and follow the directions that are given. Three different levels of hazard notices may appear in your manuals. Following are examples of all three levels.

Note For general safety information, see the safety information provided with

your system.

Danger notices indicate the presence of a hazard with a high level of risk which, if ignored, will result in death, severe personal injury, or substantial property damage.

Warning notices indicate the presence of a hazard with a medium level of risk which, if ignored, can result in death, severe personal injury, or substantial property damage.

Caution notices indicate the presence of a hazard with a low level of risk which, if ignored, could cause moderate or minor personal injury, equipment damage, or endanger test integrity.

Notes Notes provide additional information about operating your system or highlight

easily overlooked items. For example:

Note Resources that are put back on the hardware lists show up at the end of

the list.

Special terms The first occurrence of special terms is shown in italics.

Illustrations Illustrations appear in this manual to clarify text. It is important for you to be

aware that these illustrations are examples only and do not necessarily represent your actual system configuration, test application, or software.

Electronic manual

conventions

This manual is available as an electronic document in the Portable Document File (PDF) format. It can be viewed on any computer that has Adobe Acrobat Reader installed.

Preface

318 Load Unit

Conventions

Hypertext links The electronic document has many hypertext links displayed in a blue font. All

blue words in the body text, along with all contents entries and index page numbers, are hypertext links. When you click a hypertext link, the application jumps to the corresponding topic.

318 Load Unit Preface

Conventions

Preface

318 Load Unit

Introduction

Model 318

Model 322

Model 359

Typical Load Units

Load Unit: Overview

The Load Unit is the primary structure for most materials testing. It is a standalone testing unit. The load unit consists of the load frame plus additional parts, such as hydraulic crosshead lifts and control modules. Load units come in different sizes and shapes. The following illustration shows typical load units with common accessories.

The Load Units are designed for testing materials. They can perform tension and compression tests, fatigue and fracture mechanics tests, as well as other tests. MTS manufactures a variety of grips, mounting fixtures, test area guards, and environmental chambers that can be used with the load unit.

318 Load Unit Introduction

What you

need to know

MTS Systems Corporation assumes that you know how to use your controller. See the appropriate manual for information about performing any controllerrelated step in this manual’s procedures. You are expected to know how to perform the following procedures:

• Turn hydraulic pressure on and off

• Select a control mode

• Adjust the actuator position

• Zero a sensor signal

• Zero a sensor output

• Use your grips and fixtures

• Define a simple test

• Run a test

Introduction

318 Load Unit

318 Load Unit: Component Identification

Component Descriptions

TEM COMPONENT DESCRIPTION

1 Crosshead

Moves the up and down the column to accommodate different sized specimens and fixtures. The crosshead is stiff and light weight; it is one end of the force train.

2 Crosshead locks

3 Crosshead lifts

Clamps the crosshead to the columns. The locks are hydraulically powered.

Raises and lowers the crosshead hydraulically to accommodate different specimen sizes. The lifts are small hydraulic actuators.

318 Load Unit Introduction

Component Descriptions

TEM COMPONENT DESCRIPTION

4 Control panel

Grip controls

Crosshea d lift control

Emergenc y Stop

5 Servovalve

6Isolation pads

7 Accumulators

8LVDT

9Manifold

The Emergency Stop button is standard; the other controls are optional.

Clamps and unclamps the hydraulically controlled grips during specimen installation and removal.

Controls the crosshead lifts to raise and lower the crosshead hydraulically.

Removes hydraulic pressure from the load unit and issues an interlock signal to the controller to stop the test program.

Controls both the flow rate and the direction of fluid entering the actuators. It determines how fast the actuator extends or retracts.

Dampens the natural frequency to about 20 Hz. Optional air inflated isolators dampen the frequency to about 2 Hz.

Stores hydraulic fluid under pressure to increase the actuator’s response time. One accumulator connects to the pressure line; the other to the return line.

Measures the displacement of the actuator’s travel. The linear variable displacement transducer (LVDT) is located inside the actuator.

Serves as the junction point between the hydraulic power unit (HPU), accumulators, servovalve, and actuator. The actuator manifold controls the hydraulic circuit that connects the hydraulic components.

10 Linear actuator

Applies axial forces to specimens. The actuator is a hydraulically powered device that provides linear displacement of (or forces into) a specimen. Grips and fixtures can be mounted to the actuator.

11 Force transducer

12 Lifting rings

Measures the axial forces applied to specimen.

Allows the load unit to be moved by lifting the entire load unit.

318 Load Unit: Component Description

The load unit is a stand alone testing structure. It consists of the following components:

• Load frame

• Crosshead lifts and locks

• Manifold

–Actuators

– Servovalves

– Accumulators

• Transducers

Introduction

• Grip controls

318 Load Unit

Load frame The load frame is the basic structure which provides the reaction mass for the

force train. The base of the load frame is one end of the reaction mass and the crosshead is the other end of the reaction mass. Installing a specimen and other fixtures or components between the load unit base and the crosshead create a force train.

The load frame and the other hydraulic components mounted to it collectively create the load unit. The base houses the actuators, servovalves, and hydraulic manifold. The crosshead is mounted above the base by two columns. A control panel lets you operate the crosshead lifts, locks, and grips to assist in specimen installation procedures.

Crosshead lifts

and locks

The crosshead can be positioned anywhere along the load frame columns. It is moved along the column with hydraulic lifts. When the crosshead is in an appropriate test position, it is hydraulically clamped to that position. This lets you change the load unit to test specimens of different lengths.

Actuator manifold The Series 298 Actuator Manifold (also called a hydraulic service manifold or

HSM) acts as the hydraulic interface between the HPU and the components mounted to the manifold (actuator, servovalves, and accumulators) of the load unit. It contains the required hydraulic porting and plumbing to accommodate the hydraulic components. The manifold can also control the hydraulic pressure to the load unit.

Actuators The Series 244 Actuators can be located in the middle of the load unit base or

crosshead. It is a hydraulically powered piston that applies displacement of (or force into) a specimen. It can apply equal power in tension and compression. One end of the test specimen is installed into a fixture which is mounted to the end of the actuator rod.

Servovalves The Series 252 Servovalves regulates the direction and flow of the hydraulic

fluid to and from a hydraulic actuator. The servovalve responds to the polarity and magnitude of the command signal generated by the controller.

Accumulators The Series 111 Accumulators suppress line-pressure fluctuations. The load unit

includes a pressure-line accumulator to provide fluid storage so a constant line pressure can be maintained at the servovalves for maximum performance. The return-line accumulator minimizes return-line pressure fluctuations.

Pressure control The load unit can be configured for several pressure configurations. The free low

configuration passes the hydraulic pressure from the HPU (or hydraulic service manifold) through the manifold to the hydraulic components. The hydraulic pressure options include on/off control, high/low/off control, and high/low/off control with a proportional valve to ramp the pressure transitions.

Transducers The load unit includes a force transducer and an LVDT.

Force The force transducer (also called load cell or force sensor) measures the amount

of tension or compression and rotational torque applied to it. It has four strain gages that form a balanced Wheatstone bridge. When forces are applied to the bridge, it becomes unbalanced and produces an electrical signal that is proportional to the force applied to it. The force transducer is a resistive device and requires a DC conditioner to process the axial signal from the Wheatstone bridge.

318 Load Unit Introduction

LVDT The LVDT measures the linear actuator’s travel. The LVDT consists of a

transformer with one primary and two secondary coils wound on a common cylinder. The coil is stationary inside the actuator. A core is attached to the piston rod of the actuator. As it moves inside the coil, it produces an electrical signal that represents the position of the piston rod. The phase of the signal indicates the direction the actuator rod is moving. An LVDT requires an AC conditioner to process the signal.

Grip Controls The grip controls provide independent clamping control of the upper and lower

grips. The maximum pressure for the grip controls can be set up to 69 MPa (10,000 psi). The pressure is factory set to 20 MPa (3000 psi); 45 MPa (6500 psi); or 69 MPa (10,000 psi) to accommodate a variety of grips manufactured by MTS Systems Corporation. A front panel control allows the grip pressure to be adjusted within the factory setting. A rate control sets how fast the grips open and close.

318 Load Unit: Specifications

This section provides the specifications of the Series 318 Load Unit.

General specifications The following table lists general specifications for the Series 318 Load Unit:

ARAMETER SPECIFICATION

Load frame

Lifts

Locks

Grip control

Service manifold

Maximum flow

Axial actuator

Displacements

Accumulator Series 111 Accumulator

Hydraulic (optional)

Series 298 Actuator Manifold

114 L/min (30 gpm)

Series 244 Actuator

100 mm (4 in) 150 mm (6 in) 250 mm (10 in)

Introduction

318 Load Unit

PARAMETER SPECIFICATION

Force Ratings The Series 318 Load Units include other products. The following table lists

MODEL FRAME

FATIGUE RATING

Weight*

Base mount

318.10

318.25

318.50

Crosshead mount

318.10

318.25

318.50

* The weight specification is for lifting and moving purposes. The weight of

accessories and special fixtures must be added. The actual shipping weight must be determined by a scale.

approximate minimum weight

500 kg (1100 lb) 960 kg (2120 lb) 1900 kg (4200 lb)

555 kg (1225 lb) 1065 kg (2345 lb) 2100 kg (4625 lb)

specifications from several product information manuals. Specifications listed in the respective product information manual supersede the following specifications.

ACTUATOR

ATING

TRANSDUCER R

ATING

MOUNTING T

HREADS

318.10 100 kN (22 kip)

318.25 250 kN (55 kip)

318.50 500 kN (110 kip)

* At 21 MPa (3000 psi)

Stiffness Data Stiffness is a way to measure the deflection of the force train. Deflection rates can

25 kN (5.5 kip)

50 kN (11 kip)

100 kN (22 kip)

250 kN (55 kip)

500 kN (110 kip)

25 kN (5.5 kip)

50 kN (11 kip)

100 kN (22 kip)

250 kN (55 kip)

500 kN (110 kip)

M27 x 2 (1 - 14 UNS)

M36 x 2 (1 1/2 - 12 UNF)

M52 x 2 (2 -12 UNF)

vary 20%, depending on the actuator and force transducer you use.

318 Load Unit Introduction

For the most accurate high frequency test results, use a load unit with a fatigue

rating that is larger than its actuator’s force rating.

For example, a Model 318.25 Load Unit with a 55 kip fatigue rating and a 22 kip actuator will have smaller deflections than a Model 318.10 Load Unit with a 22 kip fatigue rating and a 22 kip actuator.

Spring rates are determined at each load unit’s full fatigue rating with its crosshead raised 1270 mm (50 in.) above the baseplate.

The Stiffness Graph shows how stiffness is affected when the height of the crosshead is changed.

DEFLECTIONS MODEL 318.10

100

KN/22 KIP

A - B base 0.15 mm 0.006 in 0.18 mm 0.007 in 0.20 mm 0.008 in

B - C columns 0.10 mm 0.004 in 0.15 mm 0.006 in 0.18 mm 0.007 in

C - D crosshead 0.13 mm 0.005 in 0.25 mm 0.010 in 0.28 mm 0.011 in

Introduction

MODEL 318.25 250

KN/55 KIP

MODEL 318.50 500

KN/110 KIP

318 Load Unit

DEFLECTIONS MODEL 318.10

Free Column Length (cm)

Free Column Length (in)

Maximum Side Load Limits (kips)

Maximum Side Load Limits (kN)

10 25 50 125 250

5 10 20 50 100

0.5

4.5

318.10

318.25

318.50

100

KN/22 KIP

A - D overall frame 0.38 mm 0.015 in 0.58 mm 0.023 in 0.66 mm 0.026 in

MODEL 318.25 250

KN/55 KIP

MODEL 318.50 500

KN/110 KIP

Spring rates

2.6 x 10

(1.5 x 10

N/m

lb/in)

4.3 x 10

(2.4 x 10

N/m

lb/in)

7.5 x 10

(4.3 x 10

N/m

ib/in)

Stiffness Graph

318 Load Unit Introduction

Series 661 Force Transducer: Specifications

The force transducer used with this system is a Series 661 Force Transducer. The following are the specifications for the force transducers.

ARAMETER SPECIFICATION

Maximum excitation voltage 15 V DC

Bridge resistance 350 ¾

Maximum crosstalk 1.0% of full scale torsional to load

Hysteresis 0.08% of full scale (250 N–2.5 kN)

Nonlinearity 0.08% of full scale

0.05% of full scale (5 kN–50 kN)

0.15% of full scale (100 kN–500 kN)

0.20% of full scale (1000 kN)

0.15% of full scale for Models 661.22/.23/.31

Temperature

Output 2 mV/V at full-scale load

Connector PT02ER-10-6P

MODEL LOAD CAPACITY

661.11-01 250 N (50 lbf)

661.11-02 500 N (100 lbf)

661.18-01 1 kN (220 lbf)

661.18-02 2.5 kN (550 lbf)

661.19-01 5 kN (550 lbf)

Usable range Compensated range Sensitivity

THREAD SIZE

M6 x 1.0 mm x 6.3 mm (1/4 - 28 UNF x 0.25 in

M6 x 1.0 mm x 6.3 mm (1/4 - 28 UNF x 0.5 in

M12 x 1.25 mm x 25.4 mm (1/2 - 20 UNF x 1.0 in)

0.004% of reading/°C (0.002%/°F)

-54°C (-65°F) to +121°C (+250°F) +21°C (+70°F) to +77°C (+170°F)

0.0036% of full scale/°C (0.0020% of full scale/°F)

WEIGHT

0.45 kg (1 lb)

2.27 kg (5 lb)

3.07 kg (6.75 lb)

661.19-02 10 kN (2.2 kip)

661.19-03 15 kN (3.3 kip)

661.19-04 25 kN (5.5 kip)

Introduction

M12 x 1.25 mm x 25.4 mm (1/2 - 20 UNF x 1.0 in)

3.07 kg (6.75 lb)

318 Load Unit

MODEL LOAD CAPACITY

THREAD SIZE

WEIGHT

661.20-01 25 kN (5.5 kip)

661.20-02 50 kN (11 kip)

661.20-03 100 kN (2.2 kip)

661.22-01 250 kN (3.3 kip)

661.23-01 500 kN (5.5 kip)

661.31-01 1000 kN (220 kip)

* The thread sizes are available with either coarse or fine threads.

M27 x 2.0 mm x 31.7 mm (1 - 14 UNS-3B x 1.25 in)

M36 x 2.0 mm (1 1/2 - 12 UNC-2B)

M52 x 2.0 mm x 48.3 mm (2.0 - 12 UN-2B x 1.9 in)

M76 x 1.75 mm x 28.4 mm (2.0 - 12 UN-2B x 1.35 in)

Dimensions The following dimensions are rounded off to the nearest millimeter or eight-inch.

9.75 kg (21.5 lb)

13.2 kg (29 lb)

16 kg (35.3 lb)

49.9 kg (110 lb)

MODEL A

661.11-01 70 mm

(2–3/4 in)

661.18-01 105 mm

(4–1/4 in)

661.19-01 105 mm

(4–1/4 in)

661.20-01 154 mm

(6 in)

661.22-01 114 mm

(4–1/2 in)

661.23-01 152 mm

(6 in)

661.31-01 222 mm

(8–3/4 in)

* This dimension applies to both ends

318 Load Unit Introduction

18 mm (3/4 in)

32 mm (1–1/4 in)

57 mm (2–1/4 in)

92 mm (3–5/8 in)

140 mm (5–1/5 in)

203 mm (8 in)

CD*E

7 mm (1/4 in)

10 mm (3/8 in)

1 mm (>1/4 in)

N/A 203 mm

N/A 305 mm

38 mm (1–1/5 in)

67 mm (2–5/8 in)

67 mm (2-5/8 in)

95 mm (3–3/4n)

203 mm (8 in)

(8 in)

(12 in)

61 mm (2–3/8 in

64 mm (2–1/5 in)

89 mm (3–1/2 in)

74 mm (2–7/8 in)

86 mm (3–3/8 in)

124 mm (4–7/8 in)

318 Load Unit: Dimensions

Standard column lengths indicated

Note: Dimensions are inches

(mm)

Weight: 1100 lbs (500 kg) is normal maximum

weight. Accessories and special fixtures

must be added. This weight specification

is for lifting and moving purposes.

Actual shipping weight must be

determined by scale.

Introduction

318.10B Load Unit Dimensions

318 Load Unit

Standard column lengths indicated

Note: Dimensions are inches

(mm)

Standard column lengths indicated

Note: Dimensions are inches

(mm)

318.25B Load Unit Dimensions

318 Load Unit Introduction

Standard column lengths

Note: Dimensions are

(mm

Weight: 4200 lbs (1900 kg) is normal

maximum weight. Accessories and

special

fixtures must be added. This weight

specification is for lifting and moving

purposes. Actual shipping weight

318.50B Load Unit Dimensions

Introduction

318 Load Unit

Standard column lengths

Standard 6" (152.5 mm) actuator stroke indicated

Note: Dimensions are

(mm

Weight: 1100 lbs (500 kg) is normal

maximum

weight. Accessories and special fixtures

must be added. This weight specification

is for lifting and moving purposes.

Actual shipping weight must be

318.10B Load Unit with Crosshead Actuator Dimensions

318 Load Unit Introduction

Standard column lengths indicated

Standard 6" (152.5 mm) actuator stroke indicated

Note: Dimensions are inches

(mm)

Weight: 2120 lbs (960 kg) is normal maximum

weight. Accessories and special fixtures

must be added. This weight specification

is for lifting and moving purposes.

Actual shipping weight must be

determined by scale.

318.25B Load Unit with Crosshead Actuator Dimensions

Introduction

318 Load Unit

Standard column lengths

Standard 6" (152.5 mm) actuator stroke indicated

Note: Dimensions are

(mm

Weight: 4200 lbs (1900 kg) is normal

maximum weight. Accessories and

special

fixtures must be added. This weight

specification is for lifting and moving

purposes. Actual shipping weight

318.50B Load Unit with Crosshead Actuator Dimensions

318 Load Unit Introduction

Introduction

318 Load Unit

Safety

General Safety Practices

This section provides information about safety issues that pertain to servohydraulic systems in general. These issues include statements to the intended use and foreseeable misuse of the system, the hazard zone, definition for the graphical hazard labeling that is affixed to your product, and other (more general) safety information that relates to the high-pressure and highperformance characteristics of MTS servohydraulic systems.

MTS test systems are designed to generate motions and forces and impart these motions and forces into a test specimen.

When you prepare to operate the system and during system operation, ensure the following:

• Do not use or allow personnel to operate the system who are not

• Do not disable safety components or features (including limit detectors,

experienced, trained, or educated in the inherent dangers associated with high-performance servo hydraulics and who are not experienced, trained, or educated with regard to the intended operation as it applies to this test system.

light curtains, or proximity switches/detectors).

• Do not attempt to operate the system without appropriate personal safety

gear (for example, hearing, hand, and eye protection).

• Do not apply energy levels that exceed the maximum energies and velocities

for the system design. Refer to the system specifications.

• Do not test a specimen that exceeds the minimum (if applicable) or

maximum allowable mass. Refer to the system specifications.

• Do not use specimens that are combustible, flammable, pressurized, or

explosive.

• Do not use humans as specimens or allow humans to ride in or on the test

specimen or the test system for any purpose unless the system is man-rated and all associated safety conditions are strictly enforced.

• Do not modify the system or replace system components using parts that are

not MTS component parts or effect repairs using parts or components that are not manufactured to MTS specifications.

• Do not operate the system in an explosive atmosphere.

• Do not use the system in a test area where uncontrolled access to the test

system is allowed when the system is in operation

• Do not operate the system unless an interlock is installed to monitor supply

pressure into the HSM and initiate a system interlock if a low or no pressure event occurs.

318 Load Unit Safety

If you have system related responsibilities (that is, if you are an operator, service engineer, or maintenance person), you should study safety information carefully before you attempt to perform any test system procedure.

You should receive training on this system or a similar system to ensure a thorough knowledge of your equipment and the safety issues that are associated with its use. In addition, you should gain an understanding of system functions by studying the other manuals supplied with your test system. Contact MTS for information about the content and dates of training classes that are offered.

It is very important that you study the following safety information to ensure that your facility procedures and the system’s operating environment do not contribute to or result in a hazardous situation. Remember, you cannot eliminate all the hazards associated with this system, so you must learn and remain aware of the hazards that apply to your system at all times. Use these safety guidelines to help learn and identify hazards so that you can establish appropriate training and operating procedures and acquire appropriate safety equipment (such as gloves, goggles, and hearing protection).

Each test system operates within a unique environment which includes the following known variables:

• Facility variables (facility variables include the structure, atmosphere, and

utilities)

• Unauthorized customer modifications to the equipment

• Operator experience and specialization

• Test specimens

Because of these variables (and the possibility of others), your system can operate under unforeseen circumstances that can result in an operating environment with unknown hazards.

Improper installation, operation, or maintenance of your system can result in hazardous conditions that can cause death, personal injury, or damage to the equipment or to the specimen. Common sense and a thorough knowledge of the system’s operating capabilities can help to determine an appropriate and safe approach to its operation.

Safety Practices Before System Operation

Before you apply hydraulic power to the test system, review and complete all of the safety practices that are applicable to your system. The goal, by doing this, is to improve the safety awareness of all personnel involved with the system and to maintain, through visual inspections, the integrity of specific system components.

Read all manuals Study the contents of this manual and the other manuals provided with your

system before attempting to perform any system function for the first time. Procedures that seem relatively simple or intuitively obvious can require a complete understanding of system operation to avoid unsafe or dangerous situations.

Safety

318 Load Unit

Locate and read

hazard placards/labels

Find, read, and follow the hazard placard instructions located on the equipment. These placards are placed strategically on the equipment to call attention to areas such as known crush points and electrical voltage hazards.

Locate Lockout/tagout

points

Know facility safe

procedures

Locate Emergency

Stop buttons

Know where the lockout/tagout point is for all of the supply energies associated with your system. This includes the hydraulic, pneumatic, electric, and water supplies (as appropriate) for your system to ensure that the system is isolated from these energies when required.

Most facilities have internal procedures and rules regarding safe practices within the facility. Be aware of these safe practices and incorporate them into your daily operation of the system.

Know the location of all the system Emergency Stop buttons so that you can stop the system quickly in an emergency. Ensure that an Emergency Stop button is located within 2 meters (6 feet) of the operator at all times.

Know controls Before you operate the system for the first time, make a trial run through the

operating procedures with the power off. Locate all hardware and software controls and know what their functions are and what adjustments they require. If any control function or operating adjustment is not clear, review the applicable information until you understand it thoroughly.

Have first aid available Accidents can happen even when you are careful. Arrange your operator

schedules so that a properly trained person is always close by to render first aid. In addition, ensure that local emergency contact information is posted clearly and in sight of the system operator.

Know potential crush

and pinch points

Be aware of potential crush and pinch points on your system and keep personnel and equipment clear of these areas.

Be aware of

component movement

with hydraulics off

Know electrical

hazards

Remember, when hydraulic power is interrupted on a servohydraulic system, it is likely that stored accumulator pressure will persist for some time within the system. In addition, it is likely that as stored energy dissipates, gravity will cause portions of the system to move.

The crosshead can slowly drift down the columns if the locks are turned off and when hydraulic pressure is turned off. The crosshead can damage any test fixtures, grips, and specimen in its path. Unlock the crosshead only to reposition it. Always lock the crosshead after you have repositioned it and never leave the crosshead unlocked.

The actuator rod can also drift down when hydraulics are turned off hitting anything in its path. This uncommanded movement is because of oil movement between the pressure/return ports and oil blow by across the piston hub. Be aware that this can happen and clear the area around the actuator rod when hydraulics are turned off.

When the system electrical power is turned on, minimize the potential for electrical shock hazards. Wear clothing and use tools that are properly insulated for electrical work. Avoid contact with exposed wiring or switch contacts.

Whenever possible, turn off electrical power when you work on or in proximity to any electrical system component. Observe the same precautions as those given for any other high-voltage machinery.

318 Load Unit Safety

Keep bystanders

safely away

Keep bystanders at a safe distance from all equipment. Never allow bystanders to touch specimens or equipment while the test is running.

Wear proper clothing Do not wear neckties, shop aprons, loose clothing or jewelry, or long hair that

could get caught in equipment and result in an injury. Remove loose clothing or jewelry and restrain long hair.

Remove flammable

fluids

Know compressed gas

hazards

Remove flammable fluids from their containers or from components before you install the container or component. If desired, you can replace the flammable fluid with a non-flammable fluid to maintain the proper proportion of weight and balance.

Most servohydraulic systems contain accumulators that require a high-pressure gas precharge (pressures that exceed 138 bar [2000 psi]). In addition, some systems can contain devices, such as static supports, that are pneumatically operated. High-pressure devices are potentially dangerous because a great amount of energy is available in the event of an uncontrolled expansion or rupture.

Safety

318 Load Unit

Observe the following safety practices when you work with high-pressure air or gases:

• When you charge an accumulator, follow all the charging instructions

provided in the appropriate product information manuals. When precharging accumulators, properly identify the type of gas to be used and the type of accumulator to be precharged.

Use only dry-pumped nitrogen to precharge nitrogen-charged accumulators. (Dry-pumped nitrogen can also be labeled “oil pumped” or “dry water pumped.”) Do not use compressed air or oxygen for precharging: the temperature increase caused by rapid gas compression can result in highly explosive conditions when hydraulic fluid is in the presence of oxygen or compressed air.

• Always follow the recommended bleeding procedures before you remove or

disassemble components that contain pressurized gas. When you bleed a gas or remove a fitting, hose, or component that contains a gas, remember that many gases cannot support life. Therefore, as the ratio of released gas to oxygen increases, so does the potential for suffocation.

• Wear appropriate safety devices to protect your hearing. Escaping air or gas

can create a noise level that can damage your hearing.

• Ensure that all pressurized air or gas is bled out of a pneumatic or gas-

charged device before you start to disassemble it. A thorough understanding of the assembly and its pressurized areas is necessary before you undertake any maintenance. Refer to the appropriate product information for the correct bleeding procedure.

Check bolt ratings and

torques

It might not be obvious or intuitive which bolts or fittings are used to restrain a pressurized area. On some assemblies, you must remove a cover plate to gain access to the structural bolts. Sometimes, to protect you from a rapid release of trapped gases, a small port is exposed when you remove this cover plate. Exposing this port ensures that the gas precharge is fully bled before disassembly. However, this is not the recommended procedure for bleeding a pneumatic or gas-charged device, because it can expose you to the dangers of escaping compressed gas and particulates that are expelled from the chamber or around the seals. Do not assume that cover plates and ports are installed in all the critical locations.

Consult MTS when in doubt about the safety or reliability of any system-related procedure or modification that involves devices that contain any type of compressed gas.

To ensure a reliable product, fasteners (such as bolts and tie rods) used in MTSmanufactured systems are torqued to specific requirements. If a fastener is loosened or the configuration of a component within the system is modified, refer to the system and component assembly drawings (located on the System Documentation CD) to determine the correct fastener, fastener rating, and torque. Overtorquing or undertorquing a fastener can create a hazardous situation due to the high forces and pressures present in MTS test systems.

318 Load Unit Safety

On rare occasions, a fastener can fail even when it is correctly installed. Failure usually occurs during torquing, but it can occur several days later. Failure of a fastener can result in a high velocity projectile. Therefore, it is a good practice to avoid stationing personnel in line with or below assemblies that contain large or long fasteners.

Practice good

housekeeping

Protect hoses and

cables

Provide proper

hydraulic fluid

filtration.

Protect accumulators

from moving objects.

Keep the floors in the work area clean. Hydraulic fluid that is spilled on any type of floor can result in a dangerous, slippery surface. Do not leave tools, fixtures, or other items not specific to the test, lying about on the floor, system, or decking.

Protect electrical cables from spilled hydraulic fluid and from excessive temperatures that can cause the cables to harden and eventually fail. Ensure that all cables have appropriate strain relief devices installed at the cable and near the connector plug. Do not use the connector plug as a strain relief.

Protect all system hoses and cables from sharp or abrasive objects that can cause the hose or cable to fail. Never walk on hoses or cables or move heavy objects over them. Consider hydraulic distribution system layout and route hoses and cables away from areas that expose them to possible damage.

When removing hydraulic hoses for equipment repair or changing testing components (for example, hydraulic grips), make sure to cap the hose ends to avoid spilling hydraulic fluid.

If the system is equipped with a non-MTS hydraulic power unit, ensure proper filtration to the hydraulic distribution system and testing components. Particles present in hydraulic fluid and cause erratic or poor system response.

Protect accumulators with supports or guards. Do not strike accumulators with moving objects. This could cause the accumulator(s) to separate from the manifold resulting in equipment damage and personal injury.

Record changes If you change any operating procedure, write the change and the date of the

change in the appropriate manual.

Provide test area

guards

Do not exceed the

Maximum Supply

Pressure

Do not disable safety

devices

Use appropriately

sized fuses

Use protective guards such as cages, enclosures, and special laboratory layouts when you work with hazardous test specimens (for example, brittle or fragmenting materials or materials that are internally pressurized).

For standard MTS systems, ensure that hydraulic supply pressure is limited to a maximum 21 MPa (3000 psi). If you system has a custom application that requires higher pressure, make sure you limit supply pressure to that rated for the custom components.

Your system might have active or passive safety devices installed to prevent system operation if the device indicates an unsafe condition. Do not disable such devices as it can result in unexpected system motion.

Whenever you replace fuses for the system or supply, ensure that you use a fuse that is appropriately sized and correctly installed. Undersized or oversized fuses can result in cables that overheat and fuses that explode. Either instance creates a fire hazard.

Safety

318 Load Unit

Provide adequate

lighting

Ensure adequate lighting to minimize the chance of operation errors, equipment damage, and personal injury. You need to see what you are doing.

Provide means to

access out-of-reach

components

Ensure equipment is

secure

Make sure you can access system components that might be out of reach while standing on the floor. For example ladders or scaffolding might be required to reach load cell connectors on tall load units.

Make sure the equipment is secure or provide vibration isolation. Some testing can be performed at resonant frequencies that might cause the equipment to vibrate and move during testing.

Safety Practices While the System Is in Operation

Wear appropriate

personal protection

Provide test area

guards

Wear eye protection when you work with high-pressure hydraulic fluid, breakable specimens, or when anything characteristic to the specimen could break apart.

Wear ear protection when you work near electric motors, pumps, or other devices that generate high noise levels. Some systems can create sound pressure levels that exceed 70 dbA during operation.

Wear appropriate personal protection equipment (gloves, boots, suits, respirators) whenever you work with fluids, chemicals, or powders that can irritate or harm the skin, respiratory system, or eyes.

Specimen temperature

changes

Handle chemicals

safely

Know servohydraulic

system interlocks

During cyclic testing, the specimen temperature can become hot enough to cause burns. Wear personal protection equipment (gloves) when handling specimens.

Whenever you use or handle chemicals (for example, hydraulic fluid, batteries, contaminated parts, electrical fluids, and maintenance waste), refer to the appropriate MSDS documentation for that material and determine the appropriate measures and equipment required to handle and use the chemical safely. Ensure that the chemical is disposed of appropriately.

Interlock devices should always be used and properly adjusted. Interlock devices are designed to minimize the chance of accidental damage to the test specimen or the equipment. Test all interlock devices for proper operation immediately before a test. Do not disable or bypass any interlock devices as doing so could allow hydraulic pressure to be applied regardless of the true interlock condition. The Reset/Override button is a software function that can be used to temporarily override an interlock while attempting to start the hydraulic power unit and gain control of the system.

Know system limits Never rely on system limits such as mechanical limits or software limits to

protect you or any personnel. System limits are designed to minimize the chance of accidental damage to test specimens or to equipment. Test all limits for proper operation immediately before a test. Always use these limits and adjust them properly.

318 Load Unit Safety

Do not disturb sensors Do not bump, wiggle, adjust, disconnect, or otherwise disturb a sensor (such as

an accelerometer or extensometer) or its connecting cable when hydraulic pressure is applied.

Ensure secure cables Do not change any cable connections when electrical power or hydraulic pressure

is applied. If you attempt to change a cable connection while the system is in operation, an open control loop condition can result. An open control loop condition can cause a rapid, unexpected system response which can result in severe personal injury, death, or damage to equipment. Also, ensure that all cables are connected after you make any changes in the system configuration.

Stay alert Avoid long periods of work without adequate rest. In addition, avoid long periods

of repetitious, unvarying, or monotonous work because these conditions can contribute to accidents and hazardous situations. If you are too familiar with the work environment, it is easy to overlook potential hazards that exist in that environment.

Contain small leaks Do not use your fingers or hands to stop small leaks in hydraulic or pneumatic

hoses. Substantial pressures can build up, especially if the hole is small. These high pressures can cause the oil or gas to penetrate your skin, causing painful and dangerously infected wounds. Turn off the hydraulic supply and allow the hydraulic pressure to dissipate before you remove and replace the hose or any pressurized component.

Stay clear of moving

equipment/avoid crush

points

Know the causes of

unexpected actuator

motions

Do not use RF

transmitters

Stay clear of mechanical linkages, connecting cables, and hoses that move because you can get pinched, crushed, tangled, or dragged along with the equipment. High forces generated by the system can pinch, cut, or crush anything in the path of the equipment and cause serious injury. Stay clear of any potential crush points. Most test systems can produce sudden, high-force motion. Never assume that your reactions are fast enough to allow you to escape injury when a system fails.

The high force and velocity capabilities of MTS actuators can be destructive and dangerous (especially if actuator motion is unexpected). The most likely causes of unexpected actuator response are operator error and equipment failure due to damage or abuse (such as broken, cut, or crushed cables and hoses; shorted wires; overstressed feedback devices; and damaged components within the servocontrol loop). Eliminate any condition that could cause unexpected actuator motion.

Keep radio frequency (RF) transmitters away from the workstation computers, remote terminals, and electronics consoles. Intense RF fields can cause erratic operation of the more sensitive circuits in the system.

Safety

318 Load Unit

Hazard Icons

CON DESCRIPTION

Moving parts; pinch points. Keep clear of areas noted with this label

High pressure fluid or gasses. Do not tamper with fittings or hoses.

Possible explosive or flying debris. Wear appropriate protection such as safety goggles and hearing protection.

Following are the hazard icons used on the MTS products.

Possible tipping hazard. The machine should only be moved by qualified riggers familiar with moving heavy, delicate equipment. Once in final operation position, the frame should be bolted to a suitable reaction mass.

Alternate possible tipping hazard. The machine should only be moved by qualified riggers familiar with moving heavy, delicate equipment. Once in final operation position, the frame should be bolted to a suitable reaction mass.

Read the manuals or instructions. Become familiar with safety information. Also become familiar with operating and maintenance information.

318 Load Unit Safety

CON DESCRIPTION

Alternate read the manuals or instructions. Become familiar with safety information. Also become familiar with operating and maintenance information.

Hot surfaces. Possible burn hazard. Wear personal protective equipment such as gloves when working near hot surfaces.

Object is heavy. Requires more that one person to lift and move.

318 Load Unit: Hazard Labels

This section provides information on hazard labeling. Part numbers are provided should replacement labels be necessary due to damage.

Safety

318 Load Unit

Base Assembly

View A-A

ITEM PART NUMBER DESCRIPTION

045-384-101 Warning. High force moving parts. Can cause severe injury or

equipment damage.

Stay clear and use eye protection while test is in progress.

Read instructions before operating or servicing.

037-588-901 Identification label. Includes model number, part number, serial

number, force capacity, and manufacture date.

050-275-301 Information label. No step.

050-275-201 Caution. Heavy control panel (up to 15 kg/30 lbs). Can cause

personal injury or equipment damage.

Support control panel until bolts are out. Let down slowly.

005-905-101 Warning. If lift cylinder line is opened, air may enter causing

crosshead to drop when unlocked. Bleed both cylinders before unlocking crosshead.

318 Load Unit Safety

Cylinder Assembly

ITEM PART NUMBER DESCRIPTION

037-588-801 Identification label. Includes model number, serial number,

assembly number, force, effective date, static stroke, dyn stroke, and hydrostatic bearing.

038-202-801 Warning. Subjecting this equipment to working pressure above

3000 psi (21 MPa) can result in component rupture and injury to personnel. See the product manual for safety precautions before operating.

Safety

318 Load Unit

318 Load Unit: Crush Point Hazards

ydraulicWedgeGri

Crush point areas

It is important to stay clear of any potential crush points when the system is operating. Know where the crush points are in your system and protect yourself and others from those crush points with appropriate safety devices. The following paragraphs describe crush points and precautions to take while working around crush points.

Locations A crush point exists between the platen and crosshead on load units where the

actuator piston rod and specimen move (both areas are shown). Another potential crush point exists where the lower end of the actuator piston rod extends below the platen and the bottom of the load unit/load frame.

Precautions Keep clear of any mechanical linkage that moves within a closed area. If the

linkage should move (when the system starts or due to mechanical failure), very

318 Load Unit Safety

high forces can be present that could pinch, cut, or crush anything in the path of linkage movement.

Never allow any part of your body to enter the path of machine movement or to touch moving machinery, linkages, hoses, cables, specimens, etc. These present serious crush points or pinch points.

Safety

318 Load Unit

Installation

318 Load Unit: Unpack Upright Configuration

1. Unpack the load unit.

A. Remove the shipping container (if used).

B. Remove the protective wrapping around the columns.

C. Use a clean cloth to wipe the columns clean.

Note The load unit can be moved by a fork lift as long as the load unit is

attached to its pallet.

D. Remove the bolts from the wooden beams clamping the load unit to the

pallet.

If you plan on moving the load unit with a fork lift, do not remove the bolts holding the load unit on the pallet until the load unit has been moved.

E. Cut the pallet straps.

318 Load Unit Installation

2. Inspect the load unit for shipping damage.

Look for the following:

• Scratches in the load unit or lift cylinder columns

• Damaged electrical connections

• Damaged hydraulic connections

• Dents and other structural damage

• Torn, kinked, or breaking hoses

Report any damage found to both the carrier and MTS. In the U.S. and Canada, call the MTS HELPLine at 1-800-328-2255. Elsewhere, contact your local MTS office.

3. Move the load unit to its final location.

Before you move the load unit, check that:

• The floor where the load unit will sit can bear its weight.

• The path to where the load unit will sit is clear and uncluttered.

• The area where the load unit will sit is clean and well lit, with all hoses and

cables moved out of harm’s way.

• The eyebolts are tight.

• The crosshead is manually locked.

Lift the load unit only as high as necessary. Move it slowly to its installation site.

4. Place the load unit onto the isolation pads or airmounts.

• If your load unit has isolation pads, and the load unit does not sit level,

install stock metal shims between the pads and the floor.

• If your load unit has airmounts, inflate each air mount in 5 mm (0.20 in)

increments to level the load unit.

– Check the airmounts’ pressures often to ensure they do not exceed 0.55

MPa (80 psi).

– Check the airmounts’ inflated heights to make sure that they are all

between 83 and 88 mm (3.25 and 3.5 in).

– Adjust the air pressure to level the load unit.

Installation

318 Load Unit

Airmounts can be overinflated and then explode.

WARNING

You can be seriously hurt if an airmount explodes, sending fragments flying.

Do not overinflate the airmounts.

318 Load Unit: Unpack Horizontal Configuration

Prerequisites The load unit is shipped horizontally on a wooden pallet. You will need the

following equipment to unpack the load unit:

• Lifting slings—not chains—to lift the load unit from its pallet

• Rubber mats for the load unit’s feet to rest on

• Wooden blocks for the load unit’s columns to rest on

• A knife to cut the packing straps

318 Load Unit Installation

The load unit is extremely heavy.

WARNING

The weight of the load unit can seriously hurt you and damage your load unit.

Do not allow the load unit to drop or topple. Observe the following precautions:

• Ensure that your chains, slings, and crane have a working capacity greater

than the load unit’s weight.

• Ensure that the lifting eyebolts are tight.

• Ensure that the crosshead locking bolts are fully tightened.

• Lift the load unit only high enough to clear its pallet.

• Operate the crane smoothly to prevent sudden shocks to the sling.

Installation

Unpacking the Load Unit

1. Cut the packing straps and remove any bolts as needed. Make sure the lifting eyebolts are tight.

318 Load Unit

Scratches in the load unit columns can affect how the crosshead performs.

CAUTION

Keep the base steady

Slings at center of gravity

Slide

Rubber mat

Wooden blocks

Chains will scratch the columns.

Use slings to lift the load unit from its pallet.

318 Load Unit Installation

Removing the Load Unit from Its Pallet

2. Inspect the load unit for shipping damage.

Look for the following:

• Scratches in the load unit or lift cylinder columns

• Damaged electrical connections

• Damaged hydraulic connections

• Dents and other structural damage

• Torn, kinked, or breaking hoses

Report any damage found to both the carrier and MTS. In the U.S. and Canada, call the MTS HELPLine at 1-800-328-2255. Elsewhere, contact your local MTS office.

3. Wrap slings around the columns at the load unit’s balance point.

A. With someone else steadying the load unit, slightly lift the load unit to

ensure that you have found its balance point. Keep adjusting the slings and slightly lifting the load unit until you find its balance point.

B. Lift the load unit just enough to clear its pallet. Slide the pallet out of

the way. Then lower the load unit so that its feet rest on rubber mats and its columns on the wooden blocks.

4. Lift the load unit upright.

A. Attach the chains to the lifting eyebolts. Move the crane/forklift to keep

the chains as straight as possible.

B. Slowly raise the load unit to its upright position. As the unit rises, keep

moving the crane to keep the chains as straight as possible. Do not exceed a 30° chain angle.

Installation

318 Load Unit

C. Once the load unit is upright, raise it slightly so that the pallet can be

Crane travel

30° maximum

removed.

Bringing the Load Unit Upright

Before you move the load unit, that:

• The floor where the load unit will sit can bear its weight.

• The path to where the load unit will sit is clear and uncluttered.

• The area where the load unit will sit is clean and well lit, with all hoses

and cables moved out of harm’s way.

• The eyebolts are tight.

• The crosshead is manually locked.

Lift the load unit only as high as necessary. Move it slowly to its installation site.

5. Place the load unit onto the isolation pads or airmounts.

• If your load unit has isolation pads, and the load unit does not sit level,

install stock metal shims between the pads and the floor.

318 Load Unit Installation

• If your load unit has airmounts, inflate each air mount in 5 mm (0.20 in)

WARNING

Load Unit

0.55 MPa (80 psi) maximum pressure

83-86 mm (3.25-3.5 in)

Install shims to level

Airmount Foot Support Isolation Pads

increments to level the load unit.

– Check the airmounts’ pressures often to ensure that they do not exceed

0.55 MPa (80 psi).

– Check the airmounts’ inflated heights to ensure that they are all

between 83 and 88 mm (3.25 and 3.5 in).

– Adjust the air pressure to level the load unit.

Airmounts can be overinflated and then explode.

You can be seriously hurt if an airmount explodes, sending fragments flying.

Do not overinflate the airmounts.

6. Remove the chains.

318 Load Unit: Connect Cables

Your controller manual should have cabling information about the connections described in this section. Most controller manuals provide the signal pinouts of the connector, assembly numbers for standard MTS cables, and cable specifications for cables you may build.

Installation

318 Load Unit

Prerequisite You must have either a cable assembly drawing of your test system, or you must

know the system controller well enough to determine each type of cable connection.

1. The force transducer is connected to a DC conditioner in the controller.

2. The ground connection is located on the back of the control panel. This is usually connected to a chassis ground on a console or the controller chassis.

3. The load unit control panel is connected to the controller. It contains the emergency stop and crosshead lock signals.

4. The servovalve is connected to a valve driver in the controller.

5. The actuator manifold is connected to the hydraulic service manifold (HSM) connector on the controller. The actuator manifold may include a proportional valve or solenoid valves. Controllers can have two connectors (one for each HSM type) or one connection that may be configured. See your controller documentation.

6. The displacement sensor (also called an linear variable displacement transducer or LVDT) is connected to an AC conditioner in the controller.

318 Load Unit Installation

7. Return to the installation procedure.

CAUTION

318 Load Unit: Connect Hydraulics

The procedure describes how to connect the load unit to the hydraulic power source. The load unit may be connected directly to the hydraulic power unit (also called HPU), to hydraulic plumbing in the workplace, or through a hydraulic service manifold.

Note The internal hydraulic connections from the actuator manifold and

accessories such as the hydraulic lifts and locks should already be made.

1. Connect the return line from the hydraulic power unit to the hydraulic port on the manifold labeled “R”.

2. Connect the pressure line from the hydraulic power unit to the hydraulic port on the manifold labeled “P”.

3. Connect the drain line from the hydraulic power unit to the hydraulic port on the manifold labeled “D”.

4. Turn on the HPU and check for any hydraulic pressure leaks.

5. Turn on the actuator manifold (also called a hydraulic service manifold or HSM) and check for hydraulic leaks in the load unit.

6. If you have hydraulic lifts, bleed the air out of the hydraulic lift cylinders.

7. Return to the installation procedure.

318 Load Unit: Unlock the Crosshead

When the load unit is shipped, the crosshead is clamped to the columns with the manual clamping bolts in the crosshead.

Note This procedure only applies to load units equipped with hydraulic lifts and

locks.

The crosshead can slowly drift down the columns if the locks are turned off and when hydraulic pressure is turned off.

The crosshead can damage any test fixtures, grips, and specimen in its path.

Unlock the crosshead only to reposition it. Always lock the crosshead after you have repositioned it and never leave the crosshead unlocked.

1. Turn on hydraulic pressure.

Installation

318 Load Unit

2. Fully loosen the manual crosshead locking bolts in the order shown in the

318.10

136 N·m (100 lbf·ft)

318.25

271 N·m (200 lbf·ft)

318.50

271 N·m (200 lbf·ft)

following figure.

Loosening the Manual Lock Bolts

3. Cycle the lock control to unclamp, and then reclamp, the crosshead.

4. Use the lock control to unclamp the crosshead. The unclamped symbol is shown at the right. Wait 30 seconds for the pressure in the crosshead locks to drop to zero.

5. Use the lift control to position the crosshead where you want it.

6. Use the lock control to clamp the crosshead to its current position. The

318 Load Unit Installation

clamped symbol is shown at the right. Wait 30 seconds for the locks to fully clamp the columns.

Installation

318 Load Unit

Operation

CAUTION

Load Unit: Operation Preface

This section describes the load unit controls, crush point hazards, and procedures performed during the normal, day-to-day operation of the load unit.

Application note Special considerations must be followed when using low force transducers in a

high force systems. Small force transducers are commonly used in larger systems. You need to be aware that the load unit can produce forces that exceed the rating of the low force transducer.

Low force transducers in high force systems can be exposed to excessive forces.

Applying forces that exceed the rated capacity of the force transducer can damage the transducer.

Ensure that all test commands are within the force transducer’s rating when it is installed. Your warranty does not cover damage caused by a high force actuator.

MTS recommends the following:

• Position the crosshead so that fixtures cannot touch each other when the

actuator is fully extended. This may not always be feasible at all times, but it should be practiced whenever possible.

• Use force limits. Force limits can help in some instances but might not stop

the actuator fast enough in all situations.

• Ensure that you have selected the correct calibration for the transducer being

used. Also ensure that the system tuning has been optimized for the transducer being used.

318 Load Unit Operation

318 Load Unit: Control Module

Emergency Stop

Crosshead Lift / Lock Control

Hydraulic Grip Control

Rate

Pressure

Unclamp Clamp

Upper

Lower

Grip

Pressure

Rate

The controls for the 318 Load Unit are located on a module mounted to the front of the load unit.

Series 318 Load Unit Controls

ONTROL DESCRIPTION

Hydraulic Grip Controls

Pressure

Rate

Controls the optional hydraulic grips. Hydraulic grips let you quickly and easily install and remove specimens. The left handle controls the lower grip and the right handle controls the upper grip.

Adjusts the amount of hydraulic pressure to the grips. The adjustment range is 1–21 MPa (100–3000 psi) or 1–69 MPa (100–10,000 psi). The highest pressure setting depends on the maximum pressure setting. Adjust the control clockwise to increase the hydraulic pressure. Use the pressure gage to measure the clamping force.

Adjusts how fast the grips clamp and unclamp.

Adjust the control clockwise to slow the clamping of the specimen.

Operation

318 Load Unit

Series 318 Load Unit Controls

Stop

Down

Unlock Lock

ONTROL DESCRIPTION

Crosshead Lift/Lock Controls

Emergency Stop

Controls the movement and clamping of the crosshead. The left handle raises and lowers the crosshead. The right handle locks and unlocks the crosshead. The crosshead must not be moved while it is clamped.

Shuts down the hydraulic pressure and stops the test program. Press this button to shut down hydraulic power, and twist the switch clockwise to release it. Use the Emergency Stop button to shut down your test if something unexpected should happen.

318 Load Unit Operation

318 Load Unit: Crush Point Hazards

ydraulicWedgeGri

Crush point areas

Locations A crush point exists between the platen and crosshead on load units where the

Precautions Keep clear of any mechanical linkage that moves within a closed area. If the

linkage should move (when the system starts or due to mechanical failure), very high forces can be present that could pinch, cut, or crush anything in the path of linkage movement.

Never allow any part of your body to enter the path of machine movement or to touch moving machinery, linkages, hoses, cables, specimens, etc. These present serious crush points or pinch points.

318 Load Unit: Specimen Installation

The procedure to install a specimen varies due to the variety of test fixtures, grips, and the type of specimen being installed. This section should be considered a guideline. You need to modify this procedure to suit your equipment.

Operation

318 Load Unit

Prerequisite You must have the necessary grips and/or fixturing installed. You must also have

CAUTION

WARNING

the controller set up to control the actuator movement, and you must have a test program defined.

When changing hydraulic grips, make sure you cap or plug the hydraulic hoses when removed to prevent oil spillage.

Oil spillage can create an environmental concern and slippery surface that can cause personal injury. Promptly clean up any oil that might have spilled when hoses were removed.

The crosshead is very heavy.

A dropping crosshead can crush hands, damage grips, and smash specimens.

Be careful when working in a crush zone. To reduce the hazards in this procedure, observe the following:

• Ensure to set and enable displacement interlocks to limit the actuator’s

movement.

• Ensure that the crosshead is locked.

• Ensure that the columns are clean and dry.

• Keep your hands out of the crush zone except when performing the steps

needed to complete this procedure.

1. Prepare the components for specimen installation.

A. Ensure that the crosshead is locked.

B. Turn on system electrical power.

C. Turn on high hydraulic pressure.

D. Use your controller to move the actuator to its start position (usually

mid-displacement). The starting position of the actuator depends on the type of fixtures, grips, and the test being set up.

318 Load Unit Operation

The crosshead can slowly drift down the columns if the locks are turned off

CAUTION

and when hydraulic pressure is turned off.

The crosshead can damage any test fixtures, grips, and specimen in its path.

Unlock the crosshead only to reposition it. Always lock the crosshead after you have repositioned it, and never leave the crosshead unlocked.

2. Set the crosshead position.

The crosshead position depends on the length of the specimen being tested, the starting position of the actuator, and the size of the fixtures or grips being used.

3. Install the specimen.

Specimen installation varies according to the type of grip being used. See the appropriate grip manual for installation instructions. MTS manufactures a variety of grips:

• The Series 641 Hydraulic Wedge Grips (hydraulically controlled) are

specifically designed for static or fatigue testing applications. They are available with a self aligning feature. These are hydraulically controlled grips.

• The Series 643.6X Tension/Compression Grips (mechanical) are used

for testing threaded-end and button-end specimens in tension, compression, or tension/compression.

• The Series 646 Hydraulic Collet Grips (hydraulically controlled) are

designed to perform in a wide variety of testing applications (for example, high and low cycle fatigue, tension, and compression).

• The Series 647 Hydraulic Wedge Grips (hydraulically controlled) are

specifically designed for static or fatigue testing applications. There are a variety of configurations of this grip.

• The Series Advantage Wedge Grips are specifically designed for static

or fatigue testing applications. These are a mechanical version of the Series 647 Hydraulic Wedge Grips.

• Specialty grips (mechanical) are designed to grip specific types of

material such as string, tread, tendons, etc.

Each type of grip requires the specimen or specimen fixture to fit properly into the grip. You should always review specimen installation procedures found in any grip product information manual.

Operation

318 Load Unit

Before testing, ensure both grips are clamped and the specimen is secure.

CAUTION

An insufficiently gripped specimen can cause specimen damage, equipment damage and the possibility of specimen fragmentation.

318 Load Unit: Position the Crosshead Hydraulically

1. This step pressurizes the lift actuators. The crosshead might have shifted position while hydraulic pressure was turned off.

Briefly turn the Crosshead Lift/Lock Controls to the lift crosshead position to apply a slight upward pressure to the crosshead.

Then return the lift control to the stop position.

2. Use the Crosshead Lift/Lock Controls to unclamp the crosshead.

Wait 30 seconds for the pressure in the crosshead locks to drop to zero.

Note Always lower the crosshead to where you want it. The pressure

remaining in the lift cylinders after raising the crosshead can slightly shift its alignment. Lowering the crosshead to its final position removes this pressure and improves alignment.

3. Use the Crosshead Lift/Lock Controls to move the crosshead to a point where you can install the specimen (or specimen fixture) into the upper grip or fixture without obstruction.

Set the control to the stop position “O” before proceeding.

318 Load Unit Operation

4. Use the Crosshead Lift/Lock Controls to clamp the crosshead to its current

WARNING

position.

Wait 30 seconds for the locks to fully clamp the columns.

318 Load Unit: Position the Crosshead Manually

This procedure describes how to position a crosshead for a load unit with no hydraulic crosshead lifts or locks.

The crosshead is very heavy.

A dropping crosshead can crush hands, damage grips, and smash specimens.

Observe the following precautions to reduce the possibility of unexpected crosshead movement:

• Ensure that the crosshead is locked.

• The overhead crane and lifting chains must be able to support the weight of

the crosshead (see the Crosshead Weight table below).

• Center the crane directly over the load unit.

• Remove any slack in the lifting chains before unlocking the crosshead.

• Completely loosen all crosshead locking bolts before attempting to move

the crosshead.

• Keep the columns clean and dry. The crosshead cannot be securely clamped

to greasy or damp columns.

The following procedure describes using an overhead crane to position the crosshead. You may use any device that can lift the weight of the load unit.

Model 318.10

57 kg (125 lb)

Model 318.25 Model 318.50

102 kg (225 lb) 193 kg (425 lb)

1. Center the overhead crane directly over the load unit.

2. Attach the lifting chains to the lifting rings. Remove any slack in the lifting chains while keeping chain tension to a minimum.

Operation

318 Load Unit

3. Remove the covers on the ends of the crosshead. The crosshead covers must

318.25

271 N·m (200 lbf·ft)

318.50 rear

271 N·m (200 lbf·ft)

318.10

190 N·m (140 lbf·ft)

318.50 front

271 N·m (200 lbf·ft)

be removed to access the manual locking bolts and to clean and lubricate the bolts. Six 1/4-20 screws (three top, three bottom) on each cover need 5/32 hex (not included). Hand-tighten when reinstalling the covers.

4. Loosen the crosshead locking bolts in 1/4 turn steps (counterclockwise). The following figure shows the sequence of loosening the crosshead bolts.

5. Raise or lower the crosshead using the overhead crane.

6. Manually claim the crosshead to lock the crosshead into position.

Manually Clamping the

Crosshead

The manual clamping procedure is a four step process. The four steps allow the crosshead to be clamped evenly.

318 Load Unit Operation

The crosshead is very heavy.

WARNING

CAUTION

A dropping crosshead can crush hands, damage grips, and smash specimens.

Observe the following precautions to reduce the possibility of unexpected crosshead movement:

• Ensure that the crosshead is locked.

• The overhead crane and lifting chains must be able to support the weight of

the crosshead (see the Crosshead Weight table below).

• Center the crane directly over the load unit.

• Remove any slack in the lifting chains before unlocking the crosshead.

• Completely loosen all crosshead locking bolts before attempting to move

the crosshead.

• Keep the columns clean and dry. The crosshead cannot be securely clamped

to greasy or damp columns.

Prerequisite Before clamping the crosshead in place, you must have determined the proper

crosshead position and moved the crosshead to that position.

The crosshead can slowly drift down the columns if the locks are turned off and when hydraulic pressure is turned off.

The crosshead can damage any test fixtures, grips, and specimen in its path.

Unlock the crosshead only to reposition it. Always lock the crosshead after you have repositioned it, and never leave the crosshead unlocked.

Procedure Tighten the crosshead clamping bolts according to the torque settings shown in

the following table. Torque the crosshead bolts to the values in Step 1 and so on until Step 4 is complete. Use the same sequence as when you loosened the bolts.

LOAD UNIT STEP 1STEP 2STEP 3

318.10 20 N·mm (15 lbf·ft)

171 N·m (126 lbf·ft)

190 N·m (140 lbf·ft)

TEP 4

190 N·m (140 lbf·ft)

Operation

318 Load Unit

LOAD UNIT STEP 1STEP 2STEP 3

Rate

Faster

Slower

WARNING

TEP 4

318.25 20 N·m (15 lbf·ft)

318.50 20 N·m (15 lbf·ft)

* This step ensures uniform tightness.

318 Load Unit: Adjust the Grips’ Clamp Rate

The clamp rate determines how fast the grip can clamp a specimen.

1. Ensure that both the upper grip control and lower grip control are in the unclamp position.

2. Turn on electrical power at the test controller.

3. Turn on low or high hydraulic pressure.

4. If needed, move the crosshead or actuator so that the dummy specimen can be easily installed in the lower grip.

5. Turn the Rate control fully clockwise for the slowest clamp speed.

244 N·m (180 lbf·ft)

271 N·m (200 lbf·ft)

The crosshead is very heavy.

A dropping crosshead can crush hands, damage grips, and smash specimens.

Be careful when working in a crush zone. Observe the following to reduce the hazards in this procedure:

• Ensure to set and enable displacement interlocks to limit the actuator’s

movement.

• Ensure that the crosshead is locked.

• Ensure that the columns are clean and dry.

• Keep your hands out of the crush zone except when performing the steps

needed to complete this procedure.

318 Load Unit Operation

6. Fully install the dummy specimen in the lower grip.

Clamp Unclamp

CAUTION

7. Cycle the lower grip control between the clamp and unclamp positions to clamp and unclamp the specimen.

A. Watch the speed at which the lower grip clamps and unclamps the

specimen.

B. Adjust the Rate control counterclockwise for the desired speed.

318 Load Unit: Adjust the Grips’ Clamp Force

The Pressure control adjusts the hydraulic pressure applied to the grips. The Rate control adjusts the grips’ clamping speed. They must be adjusted before the

grips can be used.

The amount of hydraulic pressure applied depends on the type of grips you are using and what you are gripping. Use your grip manual to determine the correct hydraulic pressure before adjusting the force. Experiment with a dummy specimen to find the best setting.

Note The Pressure control can adjust the grip pressure up to the maximum

output pressure setting (which is initially set by MTS Systems Corporation).

1. Ensure that both the upper grip control and lower grip control are in the unclamp position.

2. Turn on the electrical power at the test controller.

3. Turn on low or high hydraulic pressure.

4. If needed, move the crosshead or actuator so that the dummy specimen can be easily installed in the lower grip.

Grips are designed to operate within a range of hydraulic pressure.

Too much pressure can damage both the grips and the specimen.

Do not adjust grip pressure higher than the grip rating. See your grip manual to determine the correct hydraulic pressure to apply to your grips before adjusting the Pressure control.

Operation

318 Load Unit

5. Adjust the Pressure control for the desired hydraulic pressure.

Pressure

Less

6. If you exceed the desired pressure setting, adjust the Pressure control counterclockwise 1/2 turn. If pressure setting exceeds 20 MPa (3000 psi) cycle (clamp and unclamp) one of the grips. Return to Step 5.

318 Load Unit Operation

Operation

318 Load Unit

Maintenance

318 Load Unit: Maintenance Intervals 77

318 Load Unit: Daily Inspections 78

318 Load Unit: Clean the Columns 78

318 Load Unit: Prevent Rust 79

318 Load Unit: Maintain Airmount Pressures 80

318 Load Unit: Bleed the Hydraulic Lift Cylinders 81

318 Load Unit: Adjust the Hydraulic Locks 83

318 Load Unit: Lubricate the Crosshead Locking Bolts 86

318 Load Unit: Align the Force Transducer 87

111 Accumulator: Maintenance Overview 93

111 Accumulator: Check and Change Precharge Pressure 94

244 Actuator: Maintenance 98

298 HSM: Maintenance 98

252 Servovalve: Maintenance Overview 100

252 Servovalve: Replace the Filter Element 100

252 Servovalve: Adjust the Mechanical Null 102

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

Recommended service to be performed at each running time interval noted

ALENDAR TIME USING 8 HOUR RUNNING TIME RATE

PER DAY

RUNNING TIME-HOURS 8 40 80 500 1000 1,500 2,000

DAILY WEEKLY BIWEEKLY ANNUALLY

Check Actuator Platen Area to be Clean

Monitor Filter Indicators X

Check Hoses/Cables/Connectors X

Check Crosshead/Lifts/Supports X

Check Actuator to be Dry X

Check Hydraulic Service Manifold X

Check Lift Seal Condition to be Dry X

Check Lock Seal Condition to be Dry X

Bionix Lubricate Axial/Torsional Spline (75-100 hrs)

Check Actuator X

Crosshead/Load Frame

Check Crosshead/Lifts/Supports

Lift Seal Condition is Dry MTS MTS MTS MTS MTS

Lock Seal Condition is Dry MTS MTS MTS MTS MTS

Crosshead Columns are Clean MTS MTS MTS MTS MTS

†

MTS

MTS MTS MTS MTS

Column Abrasions are Acceptable MTS MTS MTS MTS MTS

Crosshead Speed is Appropriate MTS MTS MTS MTS MTS

Crosshead Unlock Causes Program Interlock

Load frame Support Airbags/Pads MTS MTS MTS MTS MTS

Crosshead Movement is Smooth MTS MTS MTS MTS MTS

Hydraulic Crosshead Locks are Functioning Properly

Bleed Crosshead Lift Cylinders MTS MTS

Lubricate Manual Crosshead Lock Bolts MTS

Actuator

Cursory Check of Actuator MTS MTS MTS MTS

Maintenance

MTS MTS MTS MTS MTS

MTS MTS

318 Load Unit

Routine Maintenance Overview Checklist

Recommended service to be performed at each running time interval noted

ALENDAR TIME USING 8 HOUR RUNNING TIME RATE

PER DAY

DAILY WEEKLY BIWEEKLY ANNUALLY

RUNNING TIME-HOURS 8 40 80 500 1000 1,500 2,000

Actuator Area is Dry MTS MTS MTS MTS

Actuator Platen Area is Clean MTS MTS MTS MTS

Piston Rod Wear is Acceptable MTS MTS MTS MTS

Bionix Lubricate Axial/Torsional Spline (75-100 hrs)

Hydraulic Service Manifold

Cursory Check of Hydraulic Service Manifold

Monitor Filter Indicators MTS MTS MTS MTS

Manifold Hose Connections are Tight MTS MTS MTS MTS

Accumulator Connections are Dry MTS MTS MTS MTS

Accumulator Connections are Tight MTS MTS MTS MTS

Accumulator Caps/Guards are Present MTS MTS MTS MTS

Oil on the Gas Side of the Piston MTS MTS MTS MTS

Check and Adjust Pressure in Accumulator

Change Filters MTS

Low Pressure Adjustment (Model 294) MTS

Hoses/Cables

Cursory Check of Hoses/Cables/ Connectors

MTS MTS MTS MTS

Absence of Hose Abrasions, Blisters, Vulcanizing

Cable Condition and Routing is Acceptable

Check Transducer Connections MTS MTS MTS MTS

Hose Connections and Crimps are Dry MTS MTS MTS MTS

Complete System

Overall System Condition is Acceptable to Use

Turning Parameters are Appropriate/ System Stable

E-Stop is Working if Applicable MTS MTS MTS MTS

318 Load Unit Maintenance

MTS MTS MTS MTS

Routine Maintenance Overview Checklist

Recommended service to be performed at each running time interval noted

ALENDAR TIME USING 8 HOUR RUNNING TIME RATE

PER DAY

DAILY WEEKLY BIWEEKLY ANNUALLY

RUNNING TIME-HOURS 8 40 80 500 1000 1,500 2,000

Response to Full Stroke Waveform, Visual and Audible

Valve Balance check displacement control MTS MTS MTS MTS

Valve Dither Response MTS MTS MTS MTS

Grips

Cursory Check of Grips/Grip Control MTS MTS MTS MTS

Grip Supply Connections are Dry MTS MTS MTS MTS

Grip Seals are Dry MTS MTS MTS MTS

Grip Action is Acceptable MTS MTS MTS MTS

Lubricate Grip Inserts MTS MTS MTS MTS

*Symbol denotes services performed by equipment operators. Most of these procedures involve visual checks that should not interfere with test system operation. These checks are also completed by trained field service engineers on each Routine Maintenance visit.

†Symbol denotes service performed by trained field service engineers as part of an MTS Routine Maintenance plan. Some of these procedures require special service tools and/or specific service training to complete.

MTS MTS MTS MTS

Maintenance

318 Load Unit

318 Load Unit: Maintenance Intervals

The following table lists the recommended interval for each of these procedures.

HAT TO DO WHEN TO DO IT

Routine Maintenance Overview Checklist

Make daily inspections

Clean the load unit columns

Prevent rust

Maintain airmount pressures

Bleed the hydraulic lift cylinders

Adjust the hydraulic locks

Lubricate the Crosshead Locking Bolts

Lubricate the crosshead locking bolts

Align the force transducer

Before the start of each day’s testing.

When the columns become greasy or dirty.

Depends on the operating environment; more often in humid environments.

When the load unit sits unevenly.

When the crosshead begins to move roughly; if the sealed side of the hydraulic supply is opened to air.

When the crosshead sticks or moves jerkily on the column.

Whenever they begin to be hard to tighten or sticky when loosened.

When the bolts begin to loosen or tighten stiffly (manual locking crossheads only).

After actuator or force transducer installation; when a better alignment between the two is desired.

Check the accumulators’ precharge pressures. Adjust if necessary

Clean exposed actuator piston rod

Change 298 HSM filter.

At least once a month; more often as required by operating conditions.

Weekly; more often as required by operating conditions.

When indicator is in bypass position or when hydraulic fluid is changed.

Perform 252 Servovalve maintenance: change filter.

Perform 252 Servovalve maintenance: adjust mechanical null.

When servovalve performance has deteriorated.

After the valve balancing procedure (electrical compensation) has been completed and the results are judged unsatisfactory.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

WARNING

318 Load Unit: Daily Inspections

Before the start of each day’s testing, do a quick inspection of your load unit. Following are typical things that should be checked daily:

• Ensure that there are no leaks from lifts or locks.

• Ensure that there are no leaks from the actuator, hydraulic service manifold,

servovalve, or accumulators.

• Ensure that electrical connections are tight, with no frayed or poorly routed

cables.

• Ensure that hoses are routed properly and fittings are not leaking.

318 Load Unit: Clean the Columns

The crosshead locks can not securely clamp the crosshead to dirty or greasy columns. You will need #1 grade kerosene and lint-free cloths to perform this procedure.

The crosshead can slide down the columns.

Crosshead cleaning takes place in a crush zone where pinched fingers and crushed hands can occur.

Do not position yourself in a crush zone. Always lock the crosshead after moving it. Always turn off hydraulic pressure before cleaning the columns. Wait two minutes for pressure to bleed off before starting work.

1. Ensure that the crosshead is locked.

2. Using a clean, lint-free cloth, clean the exposed surfaces of the columns with #1 grade kerosene.

3. If your load unit does not have hydraulic crosshead lifts, skip ahead to the next step. If your load unit has hydraulic crosshead lifts, complete the following steps:

A. Turn on system electrical power.

B. Apply high hydraulic pressure to the load unit.

4. If there is a specimen in the load unit, remove it.

5. Unlock and move the crosshead to expose the uncleaned section of the columns.

Maintenance

6. Lock the crosshead.

7. If hydraulic pressure has been turned on, turn it off. Wait two minutes for the pressure to bleed off before going on to the next step.

8. Clean the remaining sections of the columns.

318 Load Unit

318 Load Unit: Prevent Rust

WARNING

Unpainted surfaces: Spray with silicone, and then wipe with a clean, lint-free cloth. Or, wipe with a clean, lint-free cloth dampened with clean hydraulic fluid.

Chrome plated surfaces: For microscratches, wipe with a clean, lint-free cloth dampened with #1 kerosene. For rust discoloration, polish with a very fine emery cloth, and then wipe down.

Black oxide surfaces: Spray with silicone, and then wipe with a clean, lint-free cloth. Or, wipe with a clean, lint-free cloth dampened with clean hydraulic fluid.

Painted surfaces: For small scratches, use touchup paint. For large scratches, sand, prime, and use touchup paint.

Where you operate the load unit determines how often you take rust prevention measures. Humid and corrosive environments require more prevention.

Routine Maintenance Overview Checklist

Recommended

supplies:

• #1 grade kerosene

• Silicone spray

• 000 emery cloth

• Touchup paint

• Metal primer paint

• Lint-free cloths

The crosshead can slip if the columns are still damp with kerosene.

You can be hurt and your equipment damaged.

The crosshead locks cannot securely clamp on damp columns. Wait until the columns are dry to the touch before moving and locking the crosshead.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

WARNING

(80 psi)

0.55 MPa

8386 mm

(3.253.5 in)

5 mm (0.20 in)

Maximum pressure

steps

318 Load Unit: Maintain Airmount Pressures

Optional inflatable airmounts reduce vibration and noise. They are installed under the feet of the load unit. Inflation pressures must be maintained to both level and isolate the load unit.

Airmounts can be overinflated and then explode.

You can be seriously hurt if an airmount explodes, sending fragments flying.

Do not overinflate the airmounts.

1. Check the inflation pressures on each airmount. Bleed any airmount whose pressure is above 0.55 MPa (80 psi).

2. Check the airmounts’ inflated heights. They should be between 83–86 mm (3.25–3.5 in).

If the load unit is level and the airmount heights correct, you are done.

If not, continue this procedure.

3. Gradually inflate or deflate each airmount in 5 mm (0.20 in) steps as required to level the load unit.

Ensure that airmount pressures do not rise above 0.55 MPa (80 psi) and heights do not rise above 86 mm (3.5 in).

4. After leveling the load unit, check that the height of each airmount is between 83–86 mm (3.25–3.5 in).

Maintenance

5. If any airmount pressures are above 80 psi (0.55 MPa) or any airmount heights not between 83–86 mm (3.25–3.5 in), repeat Steps 1–3 until the load unit is level.

318 Load Unit

318 Load Unit: Bleed the Hydraulic Lift Cylinders

Bleed ports

Bleed both hydraulic lift cylinders whenever the crosshead does not move smoothly. Also bleed them whenever the sealed side of the hydraulic system has been opened to air. The following figure shows the location of the bleed ports for the two types of lifts commonly used.

Routine Maintenance Overview Checklist

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

CAUTION

WARNING

1/2 turn maximum

The crosshead can slowly drift down the columns if the locks are turned off and the hydraulic pressure is turned off.

The crosshead can damage any test fixtures, grips, and specimen in its path.

Unlock the crosshead only to reposition it. Always lock the crosshead after you have repositioned it, and never leave the crosshead unlocked.

1. Make sure your crosshead is locked.

2. Turn on system electrical power.

3. Reset any active interlocks at the test controller.

4. Turn on high hydraulic pressure.

5. If there is a specimen in the load unit, remove it.

The lifts contain hydraulic fluid under high pressure.

If the bleed port screw is unscrewed all the way, the screw can fly out of its port at high velocity and it could hurt you or damage your equipment.

Unscrew the bleed port screw no more than 1/2 turn to vent the trapped air.

Open to Bleed

6. Use a 1/8 inch hex key (or slotted screwdriver, depending on model number) to open one of the bleed ports. Do not unscrew the bleed port screw more than 1/2 turn.

Maintenance

318 Load Unit

Routine Maintenance Overview Checklist

No bubbles

7. Briefly turn the Lift Control to the lift crosshead position to pressurize the lift cylinders. Then return it to the stop crosshead position.

8. Shut the bleed port when bubble-free fluid begins oozing out. If necessary, again pressurize the lift cylinders to force all the air out.

9. Repeat Step 6 through Step 8 to bleed the air out of the other lift cylinder.

Note If fluid continues to leak out of a shut bleed port, turn off hydraulic

pressure to the load unit. Let the pressure in the lift cylinders return to zero. Then replace both bleed port screws (MTS par number 010-037-601).

10. Turn on high hydraulic pressure. If pressure was reduced at the hydraulic power unit, restore full pressure.

11. Briefly turn the Lift Control to the lift crosshead position to pressurize the lift cylinders. Then return it to the stop crosshead position.

12. Unlock the crosshead and exercise the crosshead. Then return to the stop crosshead position. Raise and lower the crosshead to check for smooth operation. Lock the crosshead.

13. If the crosshead does not move smoothly, go back to Step 4 and continue from there.

318 Load Unit: Adjust the Hydraulic Locks

Hydraulic locks might need adjustment if the crosshead still moves jerkily after bleeding the lift cylinders. Adjustment might also be needed if the crosshead slips under full load.

If adjusting the hydraulic locks does not fix these problems, call MTS.

1. Turn on electrical power at the controller. Do not turn on hydraulic pressure yet.

2. If the crosshead is already at a comfortable working level with no specimen installed, proceed to Step 3.

If not, position the crosshead for a comfortable working level. Proceed as follows:

318 Load Unit Maintenance

A. Reset any active interlocks at the test controller.

Routine Maintenance Overview Checklist

CAUTION

318.10

136 N·m (100 lbf·ft)

318.25

271 N·m (200 lbf·ft)

318.50

271 N·m (200 lbf·ft)

B. Turn on high hydraulic pressure.

C. If there is a specimen in the load unit, remove it.

D. Move the crosshead to a comfortable working height.

The crosshead can slowly drift down the columns if the locks are turned off and the hydraulic pressure is turned off.

The crosshead can damage any test fixtures, grips, and specimen in its path.

Unlock the crosshead only to reposition it. Always lock the crosshead after you have repositioned it, and never leave the crosshead unlocked.

3. Remove the covers on the ends of the crosshead. The crosshead covers must be removed to adjust the hydraulic locks. Four 1/4-20 screws (two top, two bottom) on each cover need 5/21 hex (not included). Hand-tighten when reinstalling the covers.

Maintenance

318 Load Unit

Routine Maintenance Overview Checklist

Tighten

Bottom out position

Loosen, then hand tighten

Loosen1/4 turn

4. Use the Lock Control to lock the crosshead. Then torque the manual crosshead locking bolts in the order shown in the following illustration.

5. Turn off hydraulic pressure.

6. Use the Lock Control to the unlock crosshead position to remove pressure from the hydraulic locks. Wait two minutes for the pressure in the locks to drop to zero before going on to the next step.

7. Tighten each lock’s cap screw until its piston bottoms out. Then loosen and hand-tighten each cap screw.

8. Loosen each of the hydraulic locks’ cap screws 1/4 turn.

9. Turn on electrical power at the test controller if you have not already done so.

10. Reset any active interlocks at the test controller.

11. Turn on high hydraulic pressure.

12. Return the Lock Control to the lock crosshead position to pressurize the hydraulic locks.

13. Fully loosen the manual crosshead locking bolts. Then turn the Lock Control to the unlock crosshead position.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

Unscrew one at a time

Clean and lubricate

14. Move the crosshead, locking and unlocking it, to check for smooth operation.

318 Load Unit: Lubricate the Crosshead Locking Bolts

Lubricate the locking bolts in a manually locked crosshead whenever they begin to be hard to tighten or sticky when loosened.

1. Remove the covers on the ends of the crosshead. The crosshead covers must be removed to lubricate the crosshead locking bolts. Four 1/4-20 screws (two top, two bottom) on each cover need 5/21 hex (not included). Hand tighten when reinstalling the covers.

2. Position the crosshead at a comfortable working height.

Maintenance

3. Lock the crosshead following your normal crosshead locking procedure.

4. Remove a single locking bolt.

5. Clean the bolt threads with a stiff nylon brush. Use degreaser if necessary. Dry the threads.

Then lightly lubricate the threads with Molykote

G-n paste.

6. Reinstall the locking bolt, tightening it to a value specified in the following table.

OAD UNIT TORQUE

318.10 190 N·m (140 lbf·ft)

318.25 271 N·m (200 lbf·ft)

318.50 271 N·m (200 lbf·ft)

7. Repeat Steps 4 and 5 until all the bolts have been lubricated.

318 Load Unit

Routine Maintenance Overview Checklist

The identification plate specifies the final torque value.

Identification plate

Stud

Hex nut

Washer

Adapter bushing

Transducer (appearance can vary)

Crosshead

Identification plate

Washer

Preloaded collar

Stud

318 Load Unit: Align the Force Transducer

This section describes how to align a force transducer with the load unit actuator. The load units shown may vary from what you may have.

The 318.10 and some 318.25 Load Units come with two types of transducer mounting hardware. One preloads the force transducer with a hex nut; the other uses a preloader collar with jackbolts or captive set screws.

The 318.50 and some 318.25 Load Units use a preloader collar with six or eight internal jackbolts to preload the force transducer.

Required equipment • Torque wrench with a 5–135 N·m (5–100 lbf·ft) range

• Molykote G·n paste

• Rubber mallet

• 0.0025 mm (0.0001 in) precision dial indicator with a magnetic base

Hex Nut Preloading Hardware Preloader Collar Hardware

318 Load Unit Maintenance

1. Get things ready.

A. If grips are installed, remove them.

B. Turn on system electrical power.

C. Turn on high hydraulic pressure.

2. Set up the load unit.

Routine Maintenance Overview Checklist

WARNING

Unscrew/Tighten

A. Position the actuator at midstroke.

B. Set and enable the test controller’s upper and lower limit detect

C. Move the crosshead so there is about 360 mm (14 in) between the top

D. Lock the crosshead.

Alignment takes place in a crush zone with hydraulic pressure on.

Hands can be crushed and equipment can be damaged equipment when hydraulics are turned on. Be careful when working in a crush zone.

Observe the following to reduce the hazards in this procedure:

• Ensure that you set and enable displacement interlocks to limit the

actuator’s movement.

interlocks to limit the actuator’s movement to 2 mm (0.10 in) in each direction.

of the actuator and the bottom of the force transducer.

• Ensure that the crosshead is locked.

• Reduce the load unit’s hydraulic pressure to low.

• Keep your hands out of the crush zone except when performing the steps

needed to complete this procedure.

E. Turn the load unit’s hydraulic pressure to high.

F. If your load unit has an antirotate actuator, unscrew the four cap screws

that attach the antirotate plate to the bottom of the piston. The antirotate plate is at the bottom of the actuator, inside the base of the load unit.

Maintenance

318 Load Unit

Routine Maintenance Overview Checklist

360° 360°

Read along the edge

Zero

3. Check the alignment.

In this step, you check the alignment between the force transducer and the actuator.

Attaching and Zeroing the Indicator

A. Attach the dial indicator to the actuator.

On a low profile force transducer, adjust the indicator to take the reading along the edge of the loading surface.

On cylindrical style force transducers, adjust the indicator so that its stylus just touches the polished bottom edge of the transducer.

B. Zero the indicator.

C. Slowly turn the actuator to rotate the indicator 360° around the force

transducer.

Stop frequently to take indicator readings. Keep your hands off the actuator and indicator when taking the readings. Compute the total indicator runout (TIR). Take the maximum dial indicator reading and subtract the minimum dial indicator reading.

OAD UNIT RATING TIR

250 kN (55 kip) or less >0.038 mm (0.0015 in)

500 kN (100 kip) 0.051 mm (0.0020 in)

D. If the TIR is 0.038 mm (0.0015 in) or less, the force transducer is

accurately aligned with the actuator. Go to Step 6.

If the TIR is greater than 0.038 mm (0.0015 in), the force transducer needs to be aligned with the actuator. Start over with Step 3.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

Tighten

G-n paste

Wooden blocks

4. Prepare the force transducer.

Depending on the type of force transducer you have, perform one of the following procedures:

• Hex nut mount only

• Preloader collar mount only

Hex nut mount only The following procedure applies only to force transducers that are mounted

to the crosshead with a single hex nut.

A. Put blocks of wood between the actuator and the force transducer. They

will support the force transducer when its mounting nut is loosened.

B. Loosen the mounting nut. Lubricate the exposed stud threads and

washer with Molykote G·n paste.

C. Tighten the mounting nut just enough to pull the force transducer

firmly against the crosshead.

D. Remove the wood blocks. Reinstall and zero the indicator.

Maintenance

Lubricating the Hex Nut

318 Load Unit

Routine Maintenance Overview Checklist

Remove, one at a time

G-n paste

Preloader collar mount

only

The following procedure applies only to force transducers that are mounted to the crosshead using a preload collar.

Loosen the six jack bolts or setscrews in 1/4 turn steps to remove most of the tension on the preloader collar, following a standard crisscross torque sequence.

• If your preloader collar has jackbolts, remove and lubricate them one at a

time. Lubricate the washer underneath the jackbolt. After you reinstall the jackbolt, tighten it enough to keep the force transducer pulled firmly against the crosshead.

• If your preloader collar has captive setscrews, unscrew them one at a time.

Lubricate the washer underneath the setscrew. Then retighten the setscrew just enough to keep the force transducer pulled firmly against the crosshead.

Preloader Collar Bolts

5. Align the force transducer.

This step describes how to align a force transducer to the crosshead.

A. Lightly tap the transducer with the rubber mallet to change its position

until you get a TIR of 0.038 mm (0.0015 in) or less.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

B. Tighten to 5% of the torque recorded on the identification plate.

C. Rotate the indicator to see if the TIR is still 0.038 mm (0.0015 in) or

D. Repeat Steps B and C to tighten the force transducer for the following

Hex nut—Tighten the nut to 5% of the final torque shown on the identification plate.

Preloader collar—Tighten the jackbolts or setscrews to 5% of the final torque shown on the identification plate.

less. If not, loosen the nut or preloader collar and return to Step 4. (Loosen the preloader collar following the sequence shown below.)

torque progression: 50%, 75%, and 100%.

Maintenance

Bolt Torque Sequence

E. Preloader collar only—For uniform tightness, retorque the jackbolts

or setscrews to 100% of the final torque shown on the identification plate.

6. Finish the procedure.

In this step, you complete the force transducer alignment procedure.

A. Remove the dial indicator.

B. If you reduced pressure at the hydraulic power unit, restore full

hydraulic pressure.

318 Load Unit

Routine Maintenance Overview Checklist

Unscrew/Tighten

C. Turn the load unit’s hydraulic pressure to off.

Anti-Rotate Actuator—Tightening the Cap Screws

D. If your load unit has an antirotate actuator, tighten the four antirotate

cap screws to a torque listed in the following table. (The actuator force rating is stated on an identification plate at the rear of the load unit.)

CTUATOR FORCE RATING TORQUE RATING

25 kN (5.5 kip) 3.7 N·m (2.7 lbf·ft)

11–500 kN (11–110 kip) 48 N·m (35 lb·ft)

111 Accumulator: Maintenance Overview

Maintaining the proper pressure level for your accumulators is essential for optimum system performance and component life. Review the following figure to familiarize yourself with the accumulator components and their locations. Also review the following guidelines before performing any procedure.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

current pressure original pressure

273 current temperatrure()+ 273 original temperature()+

---------------------------------------------------------------------

⎝⎠

⎛⎞

×=

current pressure original pressure

460 current temperatrure()+ 460 original temperature()+

---------------------------------------------------------------------

⎝⎠

⎛⎞

×=

Use the following guidelines to determine when maintenance is required.

• Check the precharge pressure at periodic intervals. The length of time

between checks depends on how the system is used. Some factors to consider when establishing this time interval are operating frequency, displacement, and duration. Start with one month intervals until you determine another interval is more appropriate.

• Maintain a log book on the condition of the precharge at each check. Use

this data to determine if the time between checks should be increased or decreased and if maintenance is required.

• Because the precharge pressure level varies with a temperature change, the

level should always be checked at the same temperature. If it is not, use one of the following formulas to determine if the precharge level is acceptable.

Degrees Celsius:

Degrees Fahrenheit:

• If a pressure line accumulator has a pressure level change of ±1.4 MPa (200

psi) between checks, the accumulator requires maintenance or the time interval between checks needs to be shortened.

• If a return line accumulator has a change of ±50% of the original pressure

level between checks, the accumulator requires maintenance or the time interval between checks needs to be shortened.

• If the precharge pressure level increases at each check interval, this indicates

that fluid is collecting on the gas side (a small amount of fluid leakage is normal). When the precharge pressure level cannot be maintained within the limits, remove the fluid and charge the accumulator. If the levels are again exceeded at the first check interval, replace the piston seals after the initial fluid has been changed.

• If the precharge pressure level decreases at each check interval, this

indicates gas leakage to the fluid side. When the precharge pressure level cannot be maintained within the limits stated in the previous guidelines, replace the accumulator piston seals.

• During normal operation, the accumulator piston should be near the center

of the accumulator cylinder. To check the approximate piston location, note the warm-to-hot transition point on the accumulator cylinder wall during operation. If the piston is near the charging stem end, the accumulator may need charging. If the piston is at the other end, the accumulator may have an excess charge, or more likely an excessive amount of hydraulic fluid has collected in the gas chamber.

111 Accumulator: Check and Change Precharge Pressure

Special equipment An accumulator charging kit (MTS part number 376986-01) is for any Series 111

Maintenance

Accumulator:

318 Load Unit

Routine Maintenance Overview Checklist

WARNING

Prerequisite To prepare the accumulator for precharge check:

Accumulators are pressurized devices.

Pressurized accumulators and their parts can become lethal projectiles if disassembled and can cause death to persons and/or damage to equipment.

Do not remove an accumulator that is pressurized. Completely remove hydraulic pressure and discharge the accumulator before any parts, except the protective cover and valve stem cap, are removed.

1. Ensure that system hydraulic pressure has been reduced to zero before proceeding. To do this, turn off the hydraulic power unit and exercise the actuator until it stops moving.

2. Close the bleed valve on the accumulator charging kit. Remove the protective cover and valve stem cap from the accumulator.

Check the Precharge

Pressure

1. Connect the charging kit chuck valve to the accumulator valve stem.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

WARNING

2. With an open-end wrench, turn the locknut counterclockwise on the accumulator valve assembly to open the valve. Read the pressure on either the high or low accumulator charging kit pressure gage.

• If the pressure reading is other than the required pressure level recorded on

the accumulator, continue with the next subsection, “Change the Precharge Pressure”.

• If the pressure level corresponds to the level recorded on the accumulator

label, turn the locknut clockwise to close the valve and continue this procedure.

3. Open the bleed valve on the accumulator charging kit and remove the chuck valve from the accumulator. Replace the valve stem cap and protective cover on the accumulator.

Change the Precharge

Pressure

Often the precharge of an accumulator mounted on a hydraulic supply line is increased to enhance system performance and reduce the transient HPS flow demands. Accumulators may be precharged to 10 MPa (1500 psi) or more, although amounts above 14 MPa (2200 psi) will have less and less performance effect in most situations. Be sure that you read the following warning before you charge your accumulator.

Accumulators have specific pressure ratings.

If the precharge pressure is too high, the accumulator can bottom out causing the release of metal particles into the hydraulic fluid. Charging accumulators above their rated level can damage system equipment.

Do not charge accumulators to pressures above their rated level. Charge accumulators below their rated fatigue pressure of 21 MPa (3000 psi) for the Model 111.11B and 22 MPa (3200 psi) for the Model 111.12C. Use a suitable regulator and gage set to an accumulator’s charges.

Decreasing pressure To decrease the precharge pressure:

1. Slowly open the bleed valve on the accumulator charging kit until gas begins to escape. When the pressure reading on the appropriate pressure gage drops to the level required, close the bleed valve.

2. Close the locknut (or close the chuck valve if you have a core-type valve). Open the bleed valve on the accumulator charging kit and remove the chuck valve from the accumulator.

3. Install the valve stem cap and protective cover.

Increasing pressure To increase the precharge pressure:

1. Close the locknut on the accumulator (or close the chuck valve for a coretype valve).

2. Open the bleed valve two turns.

Maintenance

318 Load Unit

Routine Maintenance Overview Checklist

WARNING

CAUTION

Mixing gases can produce unpredictable results.

Do not use another gas to precharge an accumulator. Use only dry nitrogen gas to precharge accumulators.

3. Connect the nitrogen supply hose from the supply bottle pressure regulator output to the input check valve on the charging kit.

4. Open the nitrogen bottle valve. Check the nitrogen bottle pressure gage on the regulator. (The bottle must contain sufficient pressure to provide an adequate gas volume.)

5. Monitor the regulator output pressure gage and adjust the regulator output pressure valve to the required level.

Rapid flow rates with pressure differentials of more than 2.1 MPa (300 psi) across the input check valve can damage the valve seal(s).

Avoid rapid and extreme pressure transitions.

Do not allow rapid flow rates. Open the regulator shut-off valve only far enough to permit a gradual transfer of gas.

6. Slowly open the regulator shut-off valve until gas is heard escaping from the accumulator charging kit bleed valve. Allow gas to slowly escape for approximately ten seconds, then close the bleed valve. Immediately close the regulator shut-off valve before the pressure reading on either the high or low charging kit pressure gage exceeds the pressure level of the accumulator.

7. Open the locknut (or open the chuck valve for a core-type valve). Slowly open the regulator shut-off valve until the pressure indicator on either the high or low charging kit pressure gage begins to rise. When the pressure is at the required pressure level (recorded on the accumulator), close the regulator shut-off valve.

8. Close the locknut (or close the chuck valve for a core type valve).

9. Open the bleed valve on the accumulator charging kit and remove the chuck valve from the accumulator.

10. Install the valve stem cap and protective cover. Close the valve on the nitrogen bottle.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

Pressure Accumulator

Return Accumulator

Inlet Filter

Dirty Filter Indicator

244 Actuator: Maintenance

The 244 Actuator is designed for extended periods of operation without extensive maintenance requirements.

A summary of the routine maintenance procedures is listed below:

Weekly Clean exposed areas of the actuator piston rod with a clean, dry, lint free rag. If

the actuator is continually exposed to a dirty operating environment, clean the piston rod on a daily basis.

Monthly Inspect actuator piston rod and seals for excessive wear and/or leakage. Small

scratches in the axial direction of the piston rod or polishing of the rod surface is considered normal operating wear.

Yearly Change actuator seals if necessary. Actuator assemblies can require more or less

frequent seal changes depending on usage. External oil leakage and/or decreased performance are indicators of seal wear. Seal replacement is considered a service procedure; contact you MTS Service Engineer for additional information.

298 HSM: Maintenance

The 298 Hydraulic Service Manifold requires the filter be changed periodically.

Maintenance

Component Identification

318 Load Unit

Routine Maintenance Overview Checklist

CAUTION

Mixing different brands of hydraulic fluid can contaminate your system.

Contaminated hydraulic fluid can cause premature wear of the hydraulic components in your system.

Do not mix different brands of hydraulic fluid. MTS Systems Corporation recommends using Mobil DTE-25 or Shell Tellus 46 AW hydraulic fluid.

The filter element should be replaced whenever:

• The indicator on the top of the filter housing is in the bypass position, which

indicates a dirty filter condition.

• The hydraulic fluid in the hydraulic power unit is changed.

Replace the filter element with one of the same rating or better.

ILTER PART NUMBER KIT NUMBER

3 micron (Beta3 = 75) 011-395-937 044-205-301

10 micron (Beta

= 75) 011-395-936 044-205-201

7.4

Perform the following procedure to change the filter element.

1. Ensure that system hydraulic pressure has been reduced to zero before proceeding. To do this, turn off the hydraulic power unit and exercise the actuator until it stops moving.

2. Turn off electrical power at the controller.

3. Place a waste fluid pan beneath the filter housing, which will accumulate any small amount of drainage from the filter housing.

4. Remove the inlet filter bowl.

5. Remove the disposable filter element from the filter bowl.

6. Empty the oil in the filter bowl into the pan. Wipe out any remaining sediment with a clean lint-free cloth.

7. Inspect the O-ring in the filter housing for any sign of deterioration. If necessary, replace the defective O-ring (part number 010-010-726).

8. Lubricate the filter element and filter housing O-rings with clean hydraulic fluid. Insert the replacement filter element into the filter bowl. Tighten the filter bowl to 34–41 N·m (25–30 lbf·ft).

9. Apply low, then high, hydraulic pressure to the actuator manifold and inspect the seal between the filter bowl and housing for any signs of leakage. If leakage exists, turn off system hydraulic and electrical power and repeat Steps 4 through 9.

318 Load Unit Maintenance

Routine Maintenance Overview Checklist

252 Servovalve: Maintenance Overview

Maintaining the Series 252 Servovalves typically involves changing the filter element (Series 252.3x only) and setting the mechanical null adjustment. Except for these procedures, further disassembly, inspection, or repair of the servovalve is not recommended and may void the servovalve warranty.

MTS does not recommend changing the 35-micron filter element in the Series

252.2x/.4x Servovalve (revision C). MTS hydraulic power supplies filter the system hydraulic fluid at 3-microns absolute. The system filters will trap most solid particle contaminants. If servovalve performance has deteriorated and the cause has been isolated to the servovalve filter, return the servovalve to MTS for service.

252 Servovalve: Replace the Filter Element

Under normal operating conditions, the 20-micron stainless steel filter used in the servovalve should be replaced only if servovalve performance has deteriorated. Ensure that other possible causes of poor performance, such as plugged system filters and/or hydraulic power supply wear, have been eliminated before replacing the servovalve filter.

Prerequisites You must have a filter kit that contains the necessary filter element replacement

parts. The filter for the Series 252.3x Servovalves is MTS part number 032-844-

101. Contact MTS Systems Corporation for the filter for the revision G Series

252.2x/4x Servovalves

100

Maintenance

318 Load Unit

MTS 318 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Technical Support

How to Get Technical Support

Before You Contact MTS

If You Contact MTS by Phone

Problem Submittal Form in MTS Manuals

Preface

Before You Begin

Conventions

Documentation Conventions

Introduction

Load Unit: Overview

318 Load Unit: Component Identification

318 Load Unit: Component Description

318 Load Unit: Specifications

Series 661 Force Transducer: Specifications

318 Load Unit: Dimensions

Safety

General Safety Practices

Safety Practices Before System Operation

Safety Practices While the System Is in Operation

Hazard Icons

318 Load Unit: Hazard Labels

318 Load Unit: Crush Point Hazards

Installation

318 Load Unit: Unpack Upright Configuration

318 Load Unit: Unpack Horizontal Configuration

318 Load Unit: Connect Cables

318 Load Unit: Connect Hydraulics

318 Load Unit: Unlock the Crosshead

Operation

Load Unit: Operation Preface

318 Load Unit: Control Module

318 Load Unit: Crush Point Hazards

318 Load Unit: Specimen Installation

318 Load Unit: Position the Crosshead Hydraulically

318 Load Unit: Position the Crosshead Manually

318 Load Unit: Adjust the Grips’ Clamp Rate

318 Load Unit: Adjust the Grips’ Clamp Force

Maintenance

Routine Maintenance Overview Checklist

318 Load Unit: Maintenance Intervals

318 Load Unit: Daily Inspections

318 Load Unit: Clean the Columns

318 Load Unit: Prevent Rust

318 Load Unit: Maintain Airmount Pressures

318 Load Unit: Bleed the Hydraulic Lift Cylinders

318 Load Unit: Adjust the Hydraulic Locks

318 Load Unit: Lubricate the Crosshead Locking Bolts

318 Load Unit: Align the Force Transducer

111 Accumulator: Maintenance Overview

111 Accumulator: Check and Change Precharge Pressure

244 Actuator: Maintenance

298 HSM: Maintenance

252 Servovalve: Maintenance Overview

252 Servovalve: Replace the Filter Element