HEIDENHAIN ND 720 User Manual v.3

User’s Manual

ND 720 ND 760

Position Display Units for Milling Machines

English (en) 12/2001

Position display (ND 720 only two axes)

 Select coordinate axes

(ND 720 only X and Y)

 Select axis-specific operating parameters

Status display:

SET = Datum setting REF = blinking:

Traverse the reference points. On continuously: Reference points have been traversed.

D = Distance-to-go display 1 2 Datum 1 or 2

Inch = Display in inches

SCL = Scaling factor

->❘❘<- = Probing an edge / centerline R = Radius/diameter display

R+/ = Radius compensation

• Select datum 1 or 2

• Page backward in the list of special functions

• Page backward in the list of parameters

HEIDENHAIN

Numerical input

• Change the algebraic sign

• Call the last dialog

• Edit parameters in the list of parameters

• Confirm entry

• Page forward in the list of parameters

Call radius compensation of the current tool

• Select special functions

• Page forward in the list of special functions

• Cancel entry

• Reset the operating mode

• Zero the selected axis

(if activated in P80)

• Select parameters CL plus two-digit number

This manual is for the ND display units with the following software numbers or higher:

Part I Operating Instructions

ND 720 for two axes 246 271-07 ND 760 for three axes 246 271-07

About this manual

This manual is divided into two parts:

Part I: Operating Instructions

 Fundamentals of positioning  ND functions

Part II: Installation and Specifications

 Mounting the display unit on the machine  Description of operating parameters  Switching inputs, switching outputs

Fundamentals 4

Switch-On, Traversing the Reference Marks 9

Datum Setting 10

Datum setting with the tool 11 Datum setting with the KT Edge Finder 13

Tool Compensation 20

Moving the Axes with Distance-To-Go 21

Bolt Hole Circles and Bolt Hole Circle Segments 23

Linear Hole Patterns 26

Working with a Scaling Factor 29

Error Messages 30

Part II Installation and Specifications Page 31

and following

Part I Operating Instructions

Fundamentals

You can skip this chapter if you are already familiar with coordinate systems, incremental and absolute dimensions, nominal positions, actual positions and distance-to-go.

Coordinate system

The Cartesian

Fundamentals

a workpiece. The Cartesian coordinate system consists of three mutually perpendicular axes X, Y and Z. The point of intersection of these axes is called the datum or origin of the coordinate system.

Think of the axes as scales with divisions (usually in millimeters) which allow us to fix points in space referenced to the datum.

To determine positions on a workpiece, the coordinate system is laid onto the workpiece.

The machine axes are parallel to the axes of the coordinate system. The Z axis is normally the tool axis.

coordinate system is used to describe the geometry of

–X

Graduation

Datum or origin

–Z

–Y

Named in honor of the French mathematician and philosopher René Descartes (1596 to 1650)

Datum setting

The workpiece drawing is used as the basis for machining the workpiece. To enable the dimensions in the drawing to be converted into traverse distances of machine axes X, Y and Z, each drawing dimension requires a datum or reference point on the workpiece (since a position can only be defined in relationship to another position).

The workpiece drawing always indicates one absolute datum (the datum for absolute dimensions). However, it may contain additional relative datums.

In the context of a numerical position display unit, datum setting means bringing the workpiece and the tool into a defined position in relation to each other and then setting the axis displays to the value that corresponds to that position. This establishes a fixed relationship between the actual positions of the axes and the displayed positions.

You can set 9 absolute datum points and store them in nonvolatile memory.

1225

750

320

Absolute datum

700

125

216,5

900

950

250

216,5 125

-125

-216,5

Relative datum

250

Fundamentals

-250

-125

-216,5

150

-150

300±0,1

325

450

Absolute workpiece positions

Each position on the workpiece is uniquely defined by its absolute coordinates.

Example Absolute coordinates of position 1:

Fundamentals

If you are working according to a workpiece drawing with absolute dimensions, then you are moving the tool to the coordinates.

Relative workpiece positions

A position can also be defined relative to the previous nominal position. The datum for the dimension is then located at the previous nominal position. Such coordinates are termed relative coordinates or chain dimensions. Incremental coordinates are indicated by a preceding I.

Example Relative coordinate of position 2 referenced to

If you are working according to a workpiece drawing with incremental dimensions, then you are moving the tool by the dimensions.

Sign for incremental dimensioning

A relative dimension has a positive sign when the axis is moved in the positive direction, and a negative sign when it is moved in the negative direction.

X = 10 mm Y = 5 mm Z = 0 mm

position 1

IX = 10 mm IY = 10 mm

Nominal position, actual position and distance-to-go

The position to which the tool is to move is called the nominal

position (

given moment is called the actual position (I).

The distance from the nominal position to the actual position is called

the distance-to-go (

Sign for distance-to-go

When you are using the distance-to-go display, the nominal position becomes the relative datum (display value 0). The distance-to-go is therefore negative when the tool moves in the positive axis direction, and positive when it moves in the negative axis direction.

). The position at which the tool is actually located at any

Fundamentals

Position encoders

The position encoders on the machine convert the movements of the machine axes into electrical signals. The ND display unit evaluates these signals, determines the actual position of the machine axes and displays the position as a numerical value.

Workpiece

If the power is interrupted, the relationship between the machine axis positions and the calculated actual positions is lost. The reference

Fundamentals

marks on the position encoders and the REF reference mark evaluation feature enable the ND to quickly reestablish this relationship again when the power is restored.

Reference marks

The scales of the position encoders contain one or more reference marks. When a reference mark is crossed over, a signal is generated which identifies that position as a reference point (scale datum = machine datum).

When this reference mark is crossed over, the ND's reference mark evaluation feature (REF) restores the relationship between axis slide positions and display values which you last defined by setting the datum. If the linear encoders have distance-coded reference marks, you only need to move the machine axes a maximum of 20 mm to do this.

Position encoder

Scale in Distance-coded linear encoder reference marks

Reference marks

Switch-On, Traversing the Reference Marks

0 è 1

ENT...CL

ENT

Crossing over the reference marks stores the most recently defined assignment of display values to axis slide positions for datum points 1 and 2 in nonvolatile memory.

Note that if you choose not to traverse the reference marks (by clearing the dialog ENT ... CL with the CL key), this relationship will be lost if the power is interrupted or when the unit is switched off.

If you wish to use multipoint axis error compensation you must traverse the reference marks (see Multipoint axis error compensation)!

Turn on power (switch located on rear panel). REF in status display starts blinking.

Confirm reference traverse mode. REF remains on continuously. Decimal points start blinking.

Cross over the reference marks in all axes in any sequence. Each axis display becomes active when its reference mark is crossed over.

Switch-On, Traversing the Reference Marks

Datum Setting

If you want to save the datum points in nonvolatile memory, you must first cross over the reference marks.

Only after crossing over the reference marks can you set new datums or activate existing ones.

Datum Setting

In P70, you can select:  Two datum points: The selected datum point

is displayed via 1 or 2

 Nine datum points: The selected datum point

is displayed in the lowest axis via d1 to d9.

There are two ways to set datums:

Touch the workpiece with the tool and then set the desired datum (see example). You can also touch two edges and set the centerline between them as a datum. The dimensions of the tool used for this are automatically accounted for (see Tool Compensation).

Probe the workpiece with the edge finder and then set the desired datum. You can also probe two edges and set the centerline between them as a datum, or touch the inside of a circle and set the circle center as a datum (see examples). The stylus radius and length are automatically accounted for if they have been entered in parameters P25 and P26, respectively (see Operating Parameters).

To call a datum you have set, proceed as follows:

You have set two datum points in P70:

Select datum 1 or 2.

You have set nine datum points in P70:

Press the datum key (d starts blinking).

ENT

Enter a datum number (1 to 9).

Datum setting with the tool

Example:

Select a datum number (see page 10).

Working plane X / Y

Tool axis Z

Tool radius R = 5 mm

Axis sequence X  Y  Z for datum setting

R=5mm

Select the special functions.

Select the probing function.

Datum Setting

SPEC

FCT

SPEC

FCT

PROBING

ENT

Confirm selection.

PROBE EDGE

ENT

Confirm Probe edge.

Select X axis (if not already selected).

SET lights. The ❘<- symbol starts to blink.

  

PROBE X (appears only briefly)

Touch workpiece edge 1 with the tool.



ENT

 

Enter position value for the datum in the Y axis. Tool radius is automatically compensated.

Datum Setting

PROBE Y (appears only briefly)

ENT

X position is captured. SET edge is

The ❘<- status symbol starts blinking.

Select the Z axis. SET lights.

shown briefly. SET starts blinking. Retract tool from workpiece. The ❘<- status symbol lights.

PROBE Z (appears only briefly)

Touch the top of the workpiece with the tool.



ENT

 

Enter position value for the datum. Tool radius is automatically compensated.

ENT

Z position is captured. SET edge is shown briefly. SET starts blinking.

Retract the tool from the workpiece.

Select the Y axis. SET lights.

The ❘<- status symbol lights.

The ❘<- status symbol starts blinking.

ENT

Enter the position value for the datum in the Z axis.

Touch workpiece edge 2 with the tool.

SPEC

FCT

After setting the datum, exit the probing

functions.

Y position is captured. SET edge is shown briefly. SET starts blinking. Retract tool from workpiece. The ❘<- status symbol lights.

only with ND 760

Datum setting with the KT Edge Finder

The ND position display units provide the following probing functions:

PROBE EDGE Setting a workpiece edge as datum

PROBE MIDPOINT Setting a midpoint between two

workpiece edges as datum

PROBE CIRCLE Setting the center of a circle as datum

The probing functions are accessible in the SPEC FCT mode of operation.

Before using the edge finder you must enter the stylus diameter and length in parameters P25 and P26, respectively (see Operating Parameters).

During all probing functions, the ND position display unit accounts for the entered dimensions.

The PROBE EDGE, PROBE MIDPOINT and PROBE CIRCLE functions are described on the following pages.

Datum Setting

Probing a workpiece edge to find a datum

The edge to be probed is parallel to the Y axis. You can probe edges and surfaces as described below to set all the coordinates of a datum.

Datum Setting

SPEC

FCT

PROBING

PROBE EDGE

SPEC

FCT

ENT

  

Select a datum number (see page 10).

Select the special functions.

Select the probing function.

Confirm the probing function.

Confirm probe edge function.

PROBE X (appears only briefly)

Select the X axis (if not already selected). SET lights. The ❘< status symbol starts blinking.

Move the edge finder to edge of workpiece until indicator in edge finder lights. SET edge is shown briefly. SET starts blinking. The ND displays the position of the edge. The ❘< status symbol lights.

Back the edge finder away from the workpiece.

Assign a position value to this edge, e.g. 52.

ENT

Datum Setting

SPEC

FCT

Exit the probing function.

Probing workpiece edges to find a midpoint datum

The edges to be probed run parallel to the Y axis.

Follow the procedure below for all midpoints between two edges.

Datum Setting

SPEC

FCT

PROBING

PROBE EDGE

ANTASTEN MITTE

SPEC

ENT

FCT

Select a datum number (see page 10).

Select the special functions.

Select the probing function.

Confirm the probing function.

Select the midpoint probing function.

  

PROBE MIDP.

ENT

Confirm the probe midpoint function. SET lights.

Set the position value for the midpoint

ENT

between the edges, e.g. 26.

Select the X axis (if not already selected).

1ST POS X (appears only briefly)

2ND POS X (appears only briefly)

  

The ->❘❘<- status symbol starts blinking.

Move edge finder toward workpiece edge 1 until the indicator in the edge finder lights. Back edge finder away from the workpiece.

Move edge finder toward workpiece edge 2 until the indicator in the edge finder lights. SET MIDPOINT is shown briefly. SET begins to blink. Back the edge finder away from the workpiece. The ->❘❘<- symbol begins to blink.

SPEC

FCT

Exit the probing functions.

Datum Setting

Probing the inside of a circle to set its center as datum

To determine the circle center, the tool must probe four points. The points to be probed are located in the X-Y plane.

Select a datum number (see page 10).

Datum Setting

SPEC

FCT

PROBING

PROBE CIRC.

ANTASTEN MITTE

SPEC

FCT

ENT

  

Select the special functions.

Select the probing function.

Confirm the probing function.

Select the circle probing function.

PROBE CIRC.

ENT

1ST POS X (appears only briefly)

2ND POS X (appears only briefly)

Confirm Probe circle.

Move edge finder toward position 1 until the indicator in the edge finder lights. Back edge finder away from workpiece.

Move edge finder toward position 2 until the indicator in the edge finder lights. Back edge finder away from workpiece.

4TH POS Y (appears only briefly)

Move edge finder toward position 4 until the indicator in the edge finder lights. CENTER X is shown briefly. The SET status display starts to blink in the X axis.

Enter position value for the

ENT

X coordinate of circle center, e.g. 26. CENTER Y is shown briefly. The SET status display starts to blink in the Y axis.

Enter position value for the Y coordinate of circle center, e.g. 0.

Datum Setting

3RD POS Y (appears only briefly)

Move edge finder toward position 3 until the indicator in the edge finder lights. Back edge finder away from workpiece.

  

SPEC

FCT

Exit the probing functions.

Tool Compensation

You can enter the axis, length and diameter of the current tool.

SPEC

Tool Compensation

FCT

TOOL DATA

TOOL DIAM.

TOOL LENGTH

only with ND 760

SPEC

FCT

ENT

TOOL AXIS

Set the tool axis.

Exit the special functions.

Select the special functions.

TOOL AXIS

SPEC

FCT

Select tool data.

Confirm tool data input mode.

and confirm with ENT.

Enter the tool length, e.g. 50 mm,

ENT

and confirm with ENT.

Enter the tool diameter, e.g. 20 mm,

ENT

  

Moving the Axes with Distance-To-Go Display

Normally, the display shows the actual position of the tool. However, it is often more helpful to display the distance remaining to the nominal position (the distance-to-go). You can then position simply by moving the axis until the display value is zero.

You can enter the absolute coordinates in the distance-to-go display. An active radius compensation will be considered.

Example: Milling a shoulder with distance-to-go

SPEC

FCT

SPEC

FCT

DELTA MODE

ENT

  

Select the special functions.

Select delta mode.

Confirm your selection, the D symbol lights.

Select the axis, enter the nominal value,

e.g. 20 mm, select radius compensation R+, confirm with ENT.

Moving the Axes with Distance-To-Go Display

Move the machine axis to zero (1).

Select the axis, enter the nominal value,

e.g. 30 mm, select radius compensation

ENT

R, and confirm with ENT.

Move the machine axis to zero (2).

Select the axis, enter the nominal

value, e.g. 70 mm, select radius

ENT

compensation R+, confirm with ENT.

Move the machine axis to zero (3).

SPEC

FCT

ENT

If appropriate, switch off the distanceto-go display.

+ 50 hidden pages

HEIDENHAIN ND 720 User Manual v.3

Specifications and Main Features

Frequently Asked Questions

User Manual