Stealth DIGI-TIG 320 AC/DC PULSE, 9012H Operator's Manual

Part No. 9012H

DIGI-TIG 320 AC/DC PULSE

OPERATOR’S

MANUAL

STEALTH DIGI-TIG 320 AC/DC PULSE

IMPORTANT

Read this Owner’s Manual completely before attempting to use this equipment.

Save this manual and keep it handy for quick reference. Pay particular attention
to the safety instructions provided for your protection. Contact your distributor if
you do not fully understand this manual.

CONTENTS

1 SAFETY 4

1.1 SIGNAL EXPLANATION 4

1.2 ARC WELDING DAMAGE 4

1.3 ELECTRIC AND MAGNETIC FIELDS INFORMATION 7

2 SUMMARY 8

2.1 BRIEF INTRODUCTION 8

2.2 MODULE EXPLANATION 9

2.3 WORKING PRINCIPLE 10

2.4 VOLT-AMPERE CHARACTERISTIC 10

3 INSTALLATION AND ADJUSTMENT 11

3.1 PARAMETERS 11

3.2 DUTY CYCLE AND OVER-HEATING 12

3.3 MOVEMENT AND PLACEMENT 12

3.4 POWER SUPPLY INPUT CONNECTION 12

3.5 POLARITY CONNECTION (MMA) 12

3.6 ASSEMBLING THE EQUIPMENT (TIG) 13

4 OPERATION 14

4.1 MACHINE CONTROLS 14

4.2 CONTROL PANEL 15

4.3 PEDAL SWITCH CONTROL 18

4.4 GUN SWITCH CURRENT CONTROL 18

4.5 ARGON ARC WELDING OPERATION 19

4.6 WELDING PARAMETERS 21

4.7 OPERATION ENVIRONMENT 26

4.8 OPERATION NOTICES 26

5 MAINTENANCE AND TROUBLESHOOTING 27

5.1 MAINTENANCE 27

5.2 TROUBLESHOOTING 28

6 PARTS LIST 31

7 MAIN ELECTRICAL DIAGRAM 32

STEALTH DIGI-TIG 320 AC/DC PULSE

STEALTH DIGI-TIG 320 AC/DC PULSE

4

1 SAFETY

1.1 Icons Explanation

• The above icons mean Warning! Notice! Running and thermal parts or receiving an
electric shock may harm you or others. The following precautions apply as a guide
to working safely.

1.2 Arc Welding Damage

• The following icons explanations are to prevent accidents to you or others during
the welding process.

• Only experienced personell can install, operate, maintain and repair the equipment.

• During the operation make sure those around you are properly protected.

• After turning off the machine power, please maintain and examine the equipment
according to 5 due to DC voltage existing in the electrolytic capacitors.

ELECTRIC SHOCK CAN KILL

• Never touch live electrical parts.

• Wear dry, hole-free gloves and clothes to insulate yourself.

• Insulate yourself from work and ground using dry insulation. Make certain the
insulation is large enough to cover your full area of physical contact with work and
ground.

• Take care when using the equipment in a confined space, on uneven surfaces and
in damp conditions.

• Shut down the incoming electrical supply prior to the equipment’s installation.

• Ensure the equipment is installed correctly and the work or metal is earthed
according to the operation manual.

• The electrode and work (or ground) circuits are ‘hot’ when the machine is on. Do not
touch these electrically ‘hot’ parts with your bare skin or wet clothing. Wear dry,
hole-free gloves to insulate hands.

• In semiautomatic or automatic wire welding, the electrode, electrode reel, welding
head, nozzle or semiautomatic welding gun are also electrically ‘hot’.

• Always ensure the work cable makes a good electrical connection and is as close as
possible to the metal being welded.

• Ensure the electrode holder, work clamp, welding cable and welding machine are
in good, safe operating condition. Replace any damaged insulation.

• Never dip the electrode in water for cooling.

• Never simultaneously touch electrically ‘hot’ parts of electrode holders connected to
two machines as voltage between the two can be the total of the open circuit voltage
of both welders.

• When working above floor level, use a safety belt to protect yourself from a fall
should you receive an electric shock.

SAFETY

§1 SAFETY

§1.1 Signal Explanation

SAFETY

§1 SAFETY

§1.1 Signal Explanation

 The above signals mean warning! Notice! Running parts and getting an electric shock or thermal parts

will take damage for your body or others. The corresponding notices are as follows. It is quite a safe

operation after taking several necessary protection measures.

§1.2 Arc Welding Damage

 The following signals and word explanations are to some damages for your body or others happening

on the welding operation. While seeing these, please remind of yourself or others to be dangerous.

 Only ones who are trained professionally can install, debug, operate, maintain and repair the

equipment.

 During the operation, non-concerned people should be lift, especially for children.

 After shut off the machine power, please maintain and examine the equipment according to §5

because of the DC voltage existing in the electrolytic capacitors.

ELECTRIC SHOCK CAN KILL.

STEALTH DIGI-TIG 320 AC/DC PULSE

5

FUMES AND GASES CAN BE DANGEROUS

• Welding may produce fumes and gases hazardous to health. Avoid breathing these
fumes and gases.

• When welding, keep your head out of fumes. Use enough ventilation and/or exhaust
at the arc to keep fumes and gases away from the breathing zone. When welding
with electrodes which require special ventilation such as stainless or hard facing or
lead or cadmium plated steel and other metals or coatings which produce highly
toxic fumes, keep exposure as low as possible and below Threshold Limit Values
using local exhaust or mechanical ventilation. In confined spaces or in some
circumstances, outdoors, a respirator may be required. Additional precautions are
also required when welding on galvanized steel.

• Do not weld in locations near chlorinated hydrocarbon vapours coming from
degreasing, cleaning or spraying operations. The heat and rays of the arc can react
with solvent vapours to form phosgene – a highly toxic gas – and other irritating
products.

• Shielding gases used for arc welding can displace air and cause injury or death.
Always use enough ventilation, especially in confined areas, to ensure breathing air
is safe.

• Read and understand the manufacturer’s instructions for this equipment and the
consumables to be used, including the material safety data sheet and follow your
employer’s safety practices.

ARC RAYS CAN BURN

• Use a shield with the correct filter and cover plates to protect your eyes from sparks
and the rays of the arc when welding or observing open arc welding.

• Use suitable clothing made from durable flame-resistant material to protect your
skin and that of your helpers from the arc rays.

• Protect nearby personnel with suitable, non-flammable screening and/or warn them
to avert their eyes from the arc rays or expose themselves to hot spatter or metal.

SELF-PROTECTION

• Keep all equipment safety guards, covers and devices in position and in good repair.
Keep hands, hair, clothing and tools away from V-belts, gears, fans and all other
moving parts when starting, operating or repairing equipment.

• Do not put your hands near the engine fan. Do not attempt to override the governor
or idler by pushing on the throttle control rods while the engine is running.

DO NOT add fuel near an open flame welding arc or when the
engine is running. Stop the machine and allow it to cool before refuelling to prevent
spilled fuel from vapourising on contact with hot engine parts and igniting. Do not
spill fuel when filling tank. If fuel is spilled, wipe it up and do not start engine until
fumes have been eliminated.

SAFETY

semiautomatic welding gun are also electrically “hot”.

 Always be sure the work cable makes a good electrical connection with the metal being welded. The

connection should be as close as possible to the area being welded.

Maintain the electrode holder, work clamp, welding cable and welding machine in good, safe

operating condition. Replace damaged insulation.

 Never dip the electrode in water for cooling.

 Never simultaneously touch electrically “hot” parts of electrode holders connected to two welders

because voltage between the two can be the total of the open circuit voltage of both welders.

 When working above floor level, use a safety belt to protect yourself from a fall should you get a

shock.

FUMES AND GASES CAN BE DANGEROUS.

SAFETY

arc when welding or observing open arc welding.

 Use suitable clothing made from durable flame-resistant material to protect your skin and that of your

helpers from the arc rays.

 Protect other nearby personnel with suitable, non-flammable screening and /or warn them not to

watch the arc nor expose themselves to the arc rays or to hot spatter or metal.

connection should be as close as possible to the area being welded.

Maintain the electrode holder, work clamp, welding cable and welding machine in good, safe

operating condition. Replace damaged insulation.

 Never dip the electrode in water for cooling.

 Never simultaneously touch electrically “hot” parts of electrode holders connected to two welders

because voltage between the two can be the total of the open circuit voltage of both welders.

 When working above floor level, use a safety belt to protect yourself from a fall should you get a

shock.

FUMES AND GASES CAN BE DANGEROUS.

 Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases.

When welding, keep your head out of the fume. Use enough ventilation and/or exhaust at the arc to keep

fumes and gases away from the breathing zone. When welding with electrodes which require special

ventilation such as stainless or hard facing or on lead or cadmium plated steel and other metals or

coatings which produce highly toxic fumes, keep exposure as low as possible and below Threshold

Limit Values using local exhaust or mechanical ventilation. In confined spaces or in some

circumstances, outdoors, a respirator may be required. Additional precautions are also required when

welding on galvanized steel.

 Do not weld in locations near chlorinated hydrocarbon vapors coming from degreasing, cleaning or

spraying operations. The heat and rays of the arc can react with solvent vapors to form phosgene, a

highly toxic gas, and other irritating products.

 Shielding gases used for arc welding can displace air and cause injury or death. Always use enough

ventilation, especially in confined areas, to insure breathing air is safe.

 Read and understand the manufacturer’s instructions for this equipment and the consumables to be

used, including the material safety data sheet and follow your employer’s safety practices.

ARC RAYS CAN BURN.

SAFETY

arc when welding or observing open arc welding.

 Use suitable clothing made from durable flame-resistant material to protect your skin and that of your

helpers from the arc rays.

 Protect other nearby personnel with suitable, non-flammable screening and /or warn them not to

watch the arc nor expose themselves to the arc rays or to hot spatter or metal.

SELF-PROTECTION

 Keep all equipment safety guards, covers and devices in position and in good repair. Keep hands, hair,

clothing and tools away from V-belts, gears, fans and all other moving parts when starting, operating or

repairing equipment.

 Do not put your hands near the engine fan. Do not attempt to override the governor or idler by

pushing on the throttle control rods while the engine is running.

DO NOT adds the fuel near an open flame welding arc or when the engine is

STEALTH DIGI-TIG 320 AC/DC PULSE

6

WELDING SPARKS can cause fire or explosion

• Remove fire hazards from the welding area. If this is not possible, cover them to
prevent the welding sparks from starting a fire. Remember that welding sparks and
hot materials from welding can easily go through small cracks and openings to
adjacent areas. Avoid welding near hydraulic lines. Have a fire extinguisher readily
available.

• Where compressed gases are to be used at the job site, special precautions should
be taken to prevent a hazardous situation.

• When not welding, make certain no part of the electrode circuit is touching the work
or ground. Accidental contact can cause overheating and create a fire hazard.

• Do not heat, cut or weld tanks, drums or containers until the proper steps have been
taken to ensure that any flammable or toxic vapours have been eliminated from
within. They can cause an explosion even though they have been ‘cleaned’.

• Vent hollow castings or containers before heating, cutting or welding. They may
ignite.

• Sparks and spatter are thrown from the welding arc. Wear oil free protective
garments such as leather gloves, heavy shirt, cuff less trousers, high shoes and a
cap over your hair. Wear ear plugs when welding out of position or in a confined
space. Always wear safety glasses with side shields when in a welding area.

• Connect the work cable to the work as close to the welding area as practical. Keep
work cables connected to the building framework or other locations away from the
welding area.

Rotating parts may be dangerous

• Use only compressed gas cylinders containing the correct shielding gas for the
process used and properly operating regulators designed for the gas and pressure
used. All hoses, fittings, etc. should be suitable for the application and maintained
in good condition.

• Always keep cylinders in an upright position securely chained to an undercarriage or
fixed support.

• Cylinders should be located:
– Away from areas where they may be struck or subjected to physical damage.
– A safe distance from arc welding or cutting operations and any other source of
heat, sparks, or flame.

• Never allow the electrode, electrode holder or any other electrically ‘hot’ parts to
touch a cylinder.

• Keep your head and face away from the cylinder valve outlet when opening the
cylinder valve.

• Valve protection caps should always be in place and hand tight except when the
cylinder is in use or connected for use.

SAFETY

an explosion even though they have been “cleaned”.

 Vent hollow castings or containers before heating, cutting or welding. They may explode.

 Sparks and spatter are thrown from the welding arc. Wear oil free protective garments such as leather

gloves, heavy shirt, cuff less trousers, high shoes and a cap over your hair. Wear ear plugs when

welding out of position or in confined places. Always wear safety glasses with side shields when in a

welding area.

 Connect the work cable to the work as close to the welding area as practical. Work cables connected

to the building framework or other locations away from the welding area increase the possibility of the

welding current passing through lifting chains, crane cables or other alternate circuits. This can create

fire hazards or overheat lifting chains or cables until they fail.

Rotating parts may be dangerous.

SAFETY

arc when welding or observing open arc welding.

 Use suitable clothing made from durable flame-resistant material to protect your skin and that of your

helpers from the arc rays.

 Protect other nearby personnel with suitable, non-flammable screening and /or warn them not to

watch the arc nor expose themselves to the arc rays or to hot spatter or metal.

SELF-PROTECTION

 Keep all equipment safety guards, covers and devices in position and in good repair. Keep hands, hair,

clothing and tools away from V-belts, gears, fans and all other moving parts when starting, operating or

repairing equipment.

 Do not put your hands near the engine fan. Do not attempt to override the governor or idler by

pushing on the throttle control rods while the engine is running.

DO NOT adds the fuel near an open flame welding arc or when the engine is

running. Stop the engine and allow it to cool before refueling to prevent spilled fuel from vaporizing on

contact with hot engine parts and igniting. Do not spill fuel when filling tank. If fuel is spilled, wipe it

up and do not start engine until fumes have been eliminated.

STEALTH DIGI-TIG 320 AC/DC PULSE

7

1.3 Electric and Magnetic Fields

• Electric current flowing through any conductor causes localised Electric and
Magnetic Fields (EMF). The discussions of the effect of EMF is ongoing globally.
Up to now, there is no material evidence that EMF has any adverse effects on
health.
Minimise exposure to EMF as far as possible by applying the following procedures:
– Route the electrode and work cables together. Secure them with tape when
possible.
– All cables should be stored away from the operator.
– Never coil the power cable around your body.
– Make sure welding machine and power cable are far enough away from the
operator according to the working environment.
– Connect the work cable to the workpiece as close as possible to the area being
welded.
– Personnel fitted with a heart-pacemaker should keep their distance from the
welding area.

STEALTH DIGI-TIG 320 AC/DC PULSE

2 SUMMARY

2.1 Brief Introduction

The DIGI-TIG 320 AC/DC PULSE welding machine features the latest Pulse Width
Modulation (PWM) technology and Insulated Gate Bipolar Transistor (IGBT) power
module, which can change work frequency to medium frequency so as to replace the
traditional large transformer with a medium frequency transformer – making it smaller,

portable light- weight and low consumption.
The front panel parameters can be adjusted continuously and steplessly, such as start
current, crater arc current, welding current, base current, duty ratio, upslope time,
downslope time, pre-gas, post-gas, pulse frequency, hot start, arc force and arc length
etc. When welding, it takes high frequency and high voltage for arc igniting to ensure
the success ratio of igniting arc.

DIGI-TIG 320 AC/DC PULSE Characteristics

• MCU control system responds immediately to any changes.

• High frequency and high voltage arc ignition ensures successful arc ignition ratio.
Reverse polarity ignition ensures efficient ignition during TIG-AC welding.

• Avoid AC arc-break. Even if arc-break occurs the HF will keep the arc stable.

• Pedal controls the welding current.

• TIG/DC operation. If the tungesten electrode touches the workpiece when welding,
the current will drop to short-circuit current to protect tungsten.

• Intelligent protection – over-voltage, over-current, over-heat If the problems listed
before occur, the alarm lamp on the front panel will light and the output current will
be cut off. It can self-protect and prolong the working life.

• Dual purpose – AC inverter TIG/MMA and DC inverter TIG/MMA offer excellent
performance on Al-alloy / carbon steel / stainless steel / titanium.

Front panel function selections – the following six welding ways can be realised:
– DC MMA
– DC TIG
– DC Pulse TIG
– AC MMA
– AC TIG
– AC Pulse TIG

1. For DC MMA – polarity connection can be selected according to different electrodes
(please refer to 3.5).

2. For AC MMA – magnetic flow caused by invariable DC polarity can be avoided.

3. For DC TIG – DCEP is used normally (workpiece connected to positive polarity,
while torch connected to negative polarity). This connection has many character­ istics, such as stable welding arc, low tungsten pole loss, more welding current,
narrow and deep weld.

4. For AC TIG (rectangle wave) – arc is more stable than Sine AC TIG. At the same
time maximum penetration is achieved with minimum tungsten pole loss to obtain
better clearance effect.

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STEALTH DIGI-TIG 320 AC/DC PULSE

5. DC Pulsed TIG has the following characteristics:
– Pulse heating. Metal in Molten pool has short time on high temperature status
and freezes quickly, which can reduce the possibility to produce hot crack of
the materials with thermal sensitivity
– Workpiece gets little heat. Arc energy is focused. Suitable for thin sheet and
super thin sheet welding.
– Exact control heat input and size of molten pool. Depth of penetration is even
and suitable for welding one side and forming two sides and all position pipe
welding.
– High frequency arc can make metal for microlite fabric, eliminate blowhole and
improve the mechanical performance of the joint. It is also suitable for high
welding speed for improved productivity.

The DIGI-TIG 320 AC/DC PULSE welding machine is suitable for all welding positions
for a variety of plates of stainless steel, carbon steel, alloyed steel, titanium,
magnesium, cuprum, etc, also applied to pipe installation, mould repair, petro­ chemical, architectural decoration, car repair, bicycle, handicraft and DIY.

MMA Manual Metal Arc welding

PWM Pulse-Width Modulation

IGBT Insulated Gate Bipolar Transistor

TIG Tungsten Insert Gas welding

9

2.2 Module Explanation

The module explanation of arc welding machine must accord with the National
Standard GB10249, explained as follows (using the TIG 180 DC PULSE PFC MV as an
example).

TIG 320 AC/DC PULSE

SUMMARY

IGBT——Insulation Gate Bipolar Transistor

TIG——Tungsten Insert Gas welding

§2.2 Module Explanation

The module explanation of arc welding machine must accord with the correlative prescripts of

National Standard GB10249. It is explained as the following (take TIG 320 AC/DC PULSE as an

example).

TIG 320 AC/DC PULSE

PULSE

AC/DC welding machine

Max welding current 320A

TIG welding mach

ine/MMA

PULSE

AC/DC welding machine

Max welding current 320A

TIG welding machine/MMA

STEALTH DIGI-TIG 320 AC/DC PULSE

10

2.3 Working Principle

The working principle of the DIGI-TIG 320 AC/DC PULSE welding machine is shown as
follows: Three-phase 380V work frequency AC is converted into DC (about 312V), then
is converted to medium frequency AC (about 20Khz) by inverter device (IGBT), after
reducing voltage by medium transformer (the main transformer) and converting by
medium frequency (fast recovery diodes). It is output by DC or AC by IGBT selection.
The circuit adopts current feedback control technology to ensure current output
stability. Meanwhile, the welding current parameter can be adjusted continuously and
steplessly to meet with the requirements of welding craft.

2.4 Volt-Ampere Characteristic

The DIGI-TIG 320 AC/DC PULSE welding machine has an excellent volt-ampere
characteristic, as shown as the following graph. The relation between the conventional
rated loading voltage U2 and the conventional welding current I2 is as follows:

When I2≤600A, U2=10+0.04I2(V); When I2>600A,U2=34(V).

IGBT——Insulation Gate Bipolar Transistor

TIG——Tungsten Insert Gas welding

§2.2 Module Explanation

The module explanation of arc welding machine must accord with the correlative prescripts of

National Standard GB10249. It is explained as the following (take TIG 320 AC/DC PULSE as an

example).

TIG 320 AC/DC PULSE

PULSE

AC/DC welding machine

Max welding current 320A

TIG welding machine/MMA

§2.3 Working Principle

The working principle of TIG 320 400 AC/DC welding machines is shown as the following figure.

Three-phase 380V work frequency AC is rectified into DC (about 312V), then is converted to medium

frequency AC (about 20KHz) by inverter device (IGBT module), after reducing voltage by medium

transformer (the main transformer) and rectifying by medium frequency rectifier (fast recovery diodes),

then is outputted DC or AC by selecting IGBT module. The circuit adopts current feedback control

technology to insure current output stably. Meanwhile, the welding current parameter can be adjusted

continuously and steplessly to meet with the requirements of welding craft.

Rectify Inverter

Medium

frequency

transformer

Medium

frequency

rectify

Hall device

Current positive-

feedback control

DC

AC DC

AC DC

380V,50HZ

Three-phases AC

SUMMARY

2

and the

2

is as follows:

2

≤600A，U2=10+0.04I2(V); When I2＞600A,U2=34(V).

67

34

10

0 600

I

2

（A）

U

2

（V）

Working

point

Volt-ampere characteristic

The relation between the

conventional loading

voltage and welding current

Power Supply Voltage (V) 3~380±10%

Frequency (Hz) 50

TIG MMA

Rated Input Current (A) 21 27.5

Rated Input Power (Kw) 9.5 13

Power Factor 0.65

No Load Voltage (V) 61

Start Current Adjustment Range (A) 10~Welding Current

Welding Current Adjustment Range (A) 10~320

Downslope Time Adjustment Range (S) 0~10

Pre-Gas Time Adjustment Range (S) 0~2

Post-Gas Time Adjustment Range (S) 0~10

Clearance Effect (%) 5~95

Efficiency (%) ≥85

Duty Cycle (40ºC / 10 min)

60% 320A

100% 250A

Protection Class IP23

Insulation Class H

Dimensions (mm) L x W x H 570 x 240 x 385

Net Weight (Kg) 25

STEALTH DIGI-TIG 320 AC/DC PULSE

3 INSTALLATION AND ADJUSTMENT

3.1 Parameters

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DIGI-TIG 320 AC/DC PULSE

STEALTH DIGI-TIG 320 AC/DC PULSE

3.2 Duty Cycle and Over-heating

The letter ‘X’ stands for duty cycle,
which is defined as the proportion
of the time that a machine can work
continuously within a certain time (10
minutes). The rated duty cycle means
the proportion of the time that a
machine can work continuously within
10 minutes when it outputs the rated
welding current.

The relation between the duty cycle ‘X’
and the output welding current ‘I’ is
shown as the figure on the right.

If the welder is over-heating, the IGBT over-heating protection unit inside will send a
message to cut output welding current and illuminate the pilot lamp on the front
panel.

At this point, the machine should be turned off for 15 minutes to cool the fan. When
operating the machine again, the welding output current or the duty cycle should be
reduced.

3.3 Movement and Placement

Please take care when moving it the machine and keep it level.
It also can be moved by the handle on the top. Place the machine securely when in
the right location. When moving using a forklift, ensure the arm lengths are long
enough to reach outside the machine to safely lift.
The movement may result in the potential danger or substantive hazard, so please
make sure that the machine is in a safe position before using it.

3.4 Power Supply Input Connection

DIGI-TIG 320AC/DC PULSE welding machine’s power supply connects to 380V.
When the power supply voltage is over the safe working voltage, there are over-voltage
and under-voltage protection inside the welder. The alarm light will illuminate and, at
the same time, the current output will be cut off.
If the power supply voltage continually goes beyond the safe work voltage range, it will
shorten the machine’s life-span. The below measures can be used:

• Change the power supply input net (connect the welder with the stable power supply
voltage of distributor).

• Switch on the machines using power supply at the same time.

• Set the voltage stabilisation device in the front of power cable input.

3.5 Polarity Connection (MMA)

MMA (DC): Choosing the connection of DCEN or DCEP according to the different
electrodes. Please refer to the electrode manual.

MMA (AC): No requirements for polarity connection.

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STEALTH DIGI-TIG 320 AC/DC PULSE

3.6 Assembling the Equipment (TIG)

• The workpiece is connected to the positive electrode of the welding machine,
and the welding torch is connected to the negative electrode – DC POSITIVE
CONNECTION, otherwise – DC NEGATIVE CONNECTION. Generally, it is operated
in DC POSITIVE CONNECTION in TIG welding mode.

• Control of the torch switch cable consists of 2 wires, pedal control of 3 wires and
the aero socket of 12 leads.

• Consumable parts for TIG torch, such as tungsten electrode / tip / gas nozzle /
electrode shield (short/long) – contact your supplier quoting the part numbers.

• When the DIGI-TIG 320 AC/DC PULSE welding machine is operated in HF Ignition
mode, the ignition spark can cause interferences in equipment near the welding
machine. Be sure to take appropriate safety precautions or shielding measures.

DC NEGATIVE CONNECTION DC POSITIVE CONNECTION

13

INSTALLATION AND ADJUSTMENT

§3.6 Assembling the equipment (TIG)

DC POSITIVE CONNECTION

INSTALLATION AND ADJUSTMENT

§4 Operation

STEALTH DIGI-TIG 320 AC/DC PULSE

4 OPERATION

4.1 Machine Controls

1 Positive output: Positive polarity output

2 Negative output: Negative polarity output.

3 Aero socket: Connected to torch switch control wire (has 12 leads with 8-9
connected to torch switch control wire).

4 Shield gas connector: Connected to torch gas input pipe.

5 Power source switch: Switch to ‘ON’ – welder is turned on. Switch to ‘OFF’ –
welder is turned off.

6 Power source input: Connects power source.

7 Water box connector: To connect water box.

8 Shield gas input joint: Connects one head of the gas hose while the other is
connected to argon gas cylinder.

14

INSTALLATION AND ADJUSTMENT

§4.2 Control panel

4.2 Control Panel

STEALTH DIGI-TIG 320 AC/DC PULSE

15

STEALTH DIGI-TIG 320 AC/DC PULSE

Available parameters where 2T and 4T mode have been selected:

Tpr Gas pre-flow time

Unit S

Setting range 0-2

Is Starting current (only with 4T)

Unit A

Setting range 10-320

Factory setting

Tup Upslope time

Unit S

Setting range 0-10

Ip Welding current

Unit A

10-320

Ib Base current

Unit A

10-320

Dcy Ratio of pulse duration to base current duration

Unit %

Setting range 5-95

Fp Pulse frequency

Unit Hz

Setting range 0.5~200

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INSTALLATION AND ADJUSTMENT

STEALTH DIGI-TIG 320 AC/DC PULSE

Tdown Downslope time

Unit S
Setting range 0~10

Ic Crater arc current (only with 4T)

Unit S
Setting range 10~320

Tpo Gas post-flow time

Unit S
Setting range 0~10

AC frequency (only with TIG-AC)

Unit Hz
Setting range 50~250

Balance (only with TIG-AC)

Balance adjustment is mainly used to set the adjustment of eliminating metal-oxide
(such as Aluminium, Magnesium and its alloy) during AC output.

Unit
Setting range –5~+5

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STEALTH DIGI-TIG 320 AC/DC PULSE

4.3 Pedal switch control

• When plugging in the 12-lead aero-socket pedal, the machine will identify the pedal

switch and the welding current knob on the front panel will only select 2T.

• The pedal can set the maximum current required.

• The eighth and ninth of the 12-lead aero-socket is a gun switch; the first and
second is short circuit and the third, fourth and fifth control pedal resistance
adjustment.

4.4 Gun switch current control

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MAINTENANCE AND TROUBLESHOOTING

Gun switch

Adjust current button, when

it’

s pushed up, the current

increase, when it’

s pushed

down, the current decrease.

Welding current adjustment

Connects to the 12-lead aero­socket on the front panel

Maximum welding current
adjustment knob

Adjust current button.

When pushed up the current

increases. When pushed

down the current decreases.

Gun Switch

STEALTH DIGI-TIG 320 AC/DC PULSE

Introduction

• 0 Press and hold the gun switch – electromagnetic gas valve is turned on.

The shielding gas starts to flow.

• 0~t1 Pre gas time: 0~2S.

• t1~t2 Arc is ignited at t1 – output the setting value of start current.

• t2 Release the gun switch – output current slopes up from the start current.

• t2~t3 Output current rises to the setting value (Iw or Ib) – upslope time can be
adjusted.

• t3~t4 Welding process – during this period the gun switch is depressed.
Note: Select the pulsed output – base current and welding current will be

output alternately; otherwise output the setting value of welding current.

• t4 Press the torch switch again – the welding current will drop in accordance
with the selected down-slope time.

• t4~t5 Crater current time.

• t6 Loosen the gun switch – stop arc and keep argon flowing.

• t6~t7 Post-Gas Time can be set by adjusting the knob on the front panel (0~10S).

• t7 Electromagnetic valve is closed, argon ceases flowing and welding is finished.

19

4.5 Argon Arc Welding Operation

4.5.1 TIG welding (4T operation)

The start current and crater current can be pre-set. This function can
compensate the possible crater that appears at the beginning and end of
welding. Thus, 4T is suitable for the welding of medium thickness plates.

MAINTENANCE AND TROUBLESHOOTING

§4.5 Argon Arc Welding Operation

§4.5.1 TIG welding （4T operation）

The start current and crater current can be pre-set. This function can compensate the

possible crater that appears at the beginning and end of the welding. Thus, 4T is suitable for the

welding of medium thickness plates.

STEALTH DIGI-TIG 320 AC/DC PULSE

20

4.5.2 TIG welding (2T operation)

This function, without the adjustment of start current and crater current, is
suitable for re-tack welding, transient welding, thin plate welding etc.

MAINTENANCE AND TROUBLESHOOTING

 t6～t7： Post-gas time can be set by the post-gas time adjustment knob on the front panel（0～

10S）;

 t7： Electromagnetic valve is closed and stop argon flowing. Welding is finished.

§4.5.2 TIG welding (2T operation)

This function without the adjustment of start current and crater current is suitable for the

Re-tack welding、

transient welding、thin plate welding and so on.

t（s）

0

I（A）

Loosen the

welding gun

switch

Press and hold the welding

gun switch

t1 t4 t5

Arc is

ignited

Arc is

turned off

t2 t3

Welding current Is

The setting base

current Ib

Introduction

• 0 Press and hold the gun switch – electromagnetic gas valve is turned on.

The shielding gas starts to flow.

• 0~t1 Pre gas time: 0~2S.

• t1~t2 Arc is ignited and the output current rises to the setting welding current
(Iw or Ib) from the minimum welding current.

• t2~t3 During the whole welding process, the gun switch is pressed and held
without releasing.
Note: Select the pulsed output – the base current and welding current will be

output alternately; otherwise output the setting value of welding current.

• t3 Release the gun switch – welding current will drop in accordance with the
selected down-slope time.

• t3~t4 The current drops to the minimum welding current from the setting current
(Iw or Ib) and arc is turned off.

• t4~t5 Post-gas time – after the arc is turned off you can adjust it (0~10S) by
turning the knob on the front panel.

• t5 Electromagnetic valve is closed – shield gas stops flowing and welding is
complete.

Short circuit protection function

1 TIG/DC/LIFT If the tungesten electrode touches the workpiece when welding, the
current will drop to 20A which can greatly reduce the tungsten spoilage,
prolong the life of the tungsten electrode and prevent tungsten clipping.

2 TIG/DC/HF If the tungesten electrode touches the workpiece when welding, the
current will drop to 0 within 1S which can greatly reduce the tungsten
spoilage, prolong the life of the tungsten electrode and prevent tungsten
clipping.

STEALTH DIGI-TIG 320 AC/DC PULSE

3 MMA operation

If the electrode touches the workpiece over 2S, the welding current will drop auto-

matically to 0 to protect the electrode.

4 TIG operation

If the TIG torch switch is pressed quickly the welding current will drop by 50%.
If the TIG torch switch is pressed quickly again, the full welding current will return.

Notes

• First check the condition of welding and connection units for any malfunction,
such as ignition spark / gas leakage / out of control etc.

• Check whether there is enough Argon gas in the shield gas cylinder. The electro­ magnetic gas valve can be tested via the switch on the front panel.

• Do not point the torch at hand or body. When the torch switch is pressed, the arc is
ignited with a high-frequency, high-voltage spark. The ignition spark can cause
interference in equipment.

• The flow rate is set according to the welding power used. Turn the regulation screw
to adjust the gas flow shown on the gas hose pressure meter or the gas bottle
pressure meter.

• The spark ignition is most efficient if you keep a 3mm distance from the workpiece
to the tungsten electrode during the ignition.

Note: When selecting AC output, the current and the wave form are as same as the
above, but output polarity changes alternately.

4.6 Welding Parameters

4.6.1 Joint forms in TIG/MMA

INSTALLATION AND ADJUSTMENT

§4.4 Welding Parameters

§4.4.1 Joint forms in TIG/MMA

a butt joint

b lap joint c coner joint d T joint

a) butt joint b) lap joint c) corner joint d) T joint

21

STEALTH DIGI-TIG 320 AC/DC PULSE

22

4.6.2 Explanation of welding quality

4.6.3 Parameters Matching

Welding area

colour

Welding area

colour

Protection

effect

Protection

effect

Silver

Gold

Bright

Silver

Blue

Orange/

Yellow

The relationship of welding area colour and protection effect of stainless steel

The relationship of welding area colour and protection effect of Ti-alloy

Better

Better

Best

Best

Red/Grey

Blue/

Purple

Good

Good

Grey

Blue/

Grey

Bad

Bad

Black

White

Powder

Worst

Worst

MAINTENANCE AND TROUBLESHOOTING

The relation of welding area color & protect effect of stainless steel

argent , golden

blue

red-grey

grey

black
best

better

good

bad

worst

bright argent

orange-yellow

blue-purple

caesious

white powder of

titanium oxid

best

better

good

bad

worst

The corresponding relationship between gas nozzle diameter and electrode diameter

Gas nozzle diameter/mm Electrode diameter/mm

6.4 0.5

8 1.0

9.5 1.6 or 2.4

11.1 3.2

b lap joint c coner joint d T joint

The corresponding relationship between gas nozzle diameter and electrode diameter

Gas nozzle and the shield gas flow rate

MAINTENANCE AND TROUBLESHOOTING

Gas nozzle and the shield gas flow rate

Welding current

range/A

DC positive connection AC

Gas nozzle

diameter/mm

Gas flow

rate/L·min-1

Gas nozzle

diameter/mm

Gas flow

rate/L·min-1

10～100

4～9.5

4～5

8～9.5

6～8

101～150

4～9.5

4～7

9.5～11

7～10

151～200

6～13

6～8

11～13

7～10

201～300 8～13 8～9 13～16 8～15

STEALTH DIGI-TIG 320 AC/DC PULSE

23

MAINTENANCE AND TROUBLESHOOTING

Gas nozzle and the shield gas flow rate

Welding current

range/A

DC positive connection

AC

Gas nozzle

diameter/mm

Gas flow

rate/L·min

-1

Gas nozzle

diameter/mm

Gas flow

rate/L·min

-1

10～100

4～9.5

4～5

8～9.5

6～8

101～150

4～9.5

4～7

9.5～11

7～10

151～200

6～13

6～8

11～13

7～10

201～300

8～13

8～9

13～16

8～15

Notice: the above parameters originate from《Welding Dictionary》P149, Volume 1 of Edition 2.

tungsten electrode

diameter /mm

sharpened of the

electrode diameter/mm

angle of cone（°） background current/A

1.0 0.125 12 2～15

1.0 0.25 20 5～30

1.6 0.5 25 8～50

1.6 0.8 30 10～70

2.4 0.8 35 12～90

2.4 1.1 45 15～150

3.2 1.1 60 20～200

TIG of stainless steel (single run welding)

Workpiece

thickness

/mm

Joint form

tungsten

electrode

diameter/mm

welding wire

diameter/mm

Argon gas

flow rate/
L·min

-1

welding

current

(DCEP)

Welding

speed/

cm·min

-1

0.8 Butt joint 1.0 1.6 5 20～50 66

1.0 Butt joint 1.6 1.6 5 50～80 56

1.5 Butt joint 1.6 1.6 7 65～105 30

1.5

Corner

joint

1.6 1.6 7 75～125 25

2.4

Butt joint

1.6

2.4

7

85～125

30

2.4

Corner

joint

1.6 2.4 7 95～135 25

3.2 Butt joint 1.6 2.4 7 100～135 30

3.2

Corner

joint

1.6 2.4 7 115～145 25

4.8

Butt joint

2.4

3.2

8

150～225

25

4.8

Corner

joint

3.2 3.2 9 175～250 20

Stainless Steel TIG (single run welding)

24

Parameters of piping back sealing welding for mild steel (DCEP)

Parameters of piping back sealing welding for mild steel (DCEP)

MAINTENANCE AND TROUBLESHOOTING

Parameters of piping back sealing welding for mild steel（DCEP）

Piping

diameter

Φ/mm

Tungsten

electrode

diameter/mm

Gas nozzle

diameter/mm

Welding

wire

diameter/mm

Welding

current/A

Arc

voltage/V

Argon

flow rate

/

L·min

-1

Welding

rate

/

cm·min

-1

38 2.0 8 2 75～90 11～13 6～8 4～5

42 2.0 8 2 75～95 11～13 6～8 4～5

60 2.0 8 2 75～100 11～13 7～9 4～5

76 2.5 8～10 2.5 80～105 14～16 8～10 4～5

108 2.5 8～10 2.5 90～110 14～16 9～11 5～6

133 2.5 8～10 2.5 90～115 14～16 10～12 5～6

159 2.5 8～10 2.5 95～120 14～16 11～13 5～6

219 2.5 8～10 2.5

100～

120

14～16 12～14 5～6

273 2.5 8～10 2.5

110～

125

14～16 12～14 5～6

325 2.5 8～10 2.5

120～

140

14～16 12～14 5～6

MAINTENANCE AND TROUBLESHOOTING

Parameters of AC TIG (MMA) for Aluminum and its alloy

Sheet

thickness

/mm

Welding

wire

diameter

/mm

Tungste

n

electrode

diameter

/mm

Pre-heat

Temper

-ature

/℃

Weldin

g

current

/A

Argon

flow

rate

/

L·min-1

Gas

nozzle

diameter

/mm

Remark

1 1.6 2 － 45～60 7～9 8 Flange welding

1.5 1.6～2.0 2 － 50～80 7～9 8

Flange or butt

welding by one

side

2 2～2.5 2～3 － 90～120 8～12 8～12 Butt welding

3 2～3 3 －

150～

180

8～12 8～12

V-groove butt

welding

4 3 4 －

180～

200

10～15 8～12

5 3～4 4 －

180～

240

10～15 10～12

6 4 5 －

240～

280

16～20 14～16

Parameters of piping back sealing welding for mild steel（DCEP）

Piping

diameter

Φ/mm

Tungsten

electrode

diameter/mm

Gas nozzle

diameter/mm

Welding

wire

diameter/mm

Welding

current/A

Arc

voltage/V

Argon

flow rate

/

L·min

-1

Welding

rate

/

cm·min

-1

38

2.0 8 2

75～90

11～13

6～8

4～5

42

2.0 8 2

75～95

11～13

6～8

4～5

60

2.0 8 2

75～100

11～13

7～9

4～5

76

2.5

8～10

2.5

80～105

14～16

8～10

4～5

108

2.5

8～10

2.5

90～110

14～16

9～11

5～6

133

2.5

8～10

2.5

90～115

14～16

10～12

5～6

159

2.5

8～10

2.5

95～120

14～16

11～13

5～6

219

2.5

8～10

2.5

100～

120

14～16

12～14

5～6

273

2.5

8～10

2.5

110～

125

14～16

12～14

5～6

325

2.5

8～10

2.5

120～

140

14～16

12～14

5～6

Notice: the above parameters originate from《Welding Dictionary》P167, Volume 1 of Edition 2.

25

MAINTENANCE AND TROUBLESHOOTING

8 4～5 5 100

260～

320

16～20 14～16

10 4～5 5

100～

150

280～

340

16～20 14～16

12 4～5 5～6

150～

200

300～

360

18～22 16～20

14 5～6 5～6

180～

200

340～

380

20～24 16～20

16 5～6 6

200～

220

340～

380

20～24 16～20

18 5～6 6

200～

240

360～

400

25～30 16～20

20 5～6 6

200～

260

360～

400

25～30 20～22

16～20 5～6 6

200～

260

300～

380

25～30 16～20

X-groove butt

welding

22～25 5～6 6～7

200～

260

360～

400

30～35 20～22

4.7 Operation Environment

• Height above sea level below 1000m

• Operation temperature range: –10ºC~+40ºC

• Relative humidity below 90% (20ºC)

• Preferably site the machine above floor level with the maximum angle not exceeding

15º.

• Protect the machine against heavy rain, hot environments and direct sunshine

• The content of dust, acid, corrosive gas in the surrounding air or substance should

not exceed normal standards

• Take care that there is sufficient ventilation during welding and there is at least
30cm free distance between the machine and wall

4.8 Operation Notices

• Read all notes carefully before attempting to use this equipment

• Connect the ground wire with the machine directly, and refer to 3.5

• If the power switch is accidentally closed, no-load voltage may be exported. Do not

touch the output electrode with any part of your body

• Before operation ensure no other presonnnel is present without proper eye
protection

• Ensure good ventilation of the machine to improve duty ratio.

• Turn off the machine when the operation is concluded for energy source economy.

• If the power switch shuts off accidentally, do not restart until the problem is

resolved

26

5 MAINTENANCE AND TROUBLESHOOTING

5.1 Maintenance

In order to guarantee that an arc welding machine works efficiently and safely, it must

be maintained regularly. Read and understand the maintenance methods and regularly
carry out safety checks. Make any repairs as required in order to extend the service life
of the welding machine. Maintenance items are detailed in the following tables.

• Warning: Safely maintain the machine by shutting off the power supply and waiting
for 5 minutes until the capacity voltage drops to a safe voltage of 36V.

DATE MAINTENANCE CHECKS

Daily Check whether panel knob and switch in the front and at the back of arc
examination welding machine are flexible and placed correctly. If the knob has not been
correctly installed, please correct. If this is not possible, replace immediately,

If the switch is not flexible or it cannot be correctly installed, please replace
immediately. Contact your distributor if there are no parts to hand.

After switching on power, watch and listen to check the arc welding machine is
not shaking, whistling or giving out an unusual odour. If so, investigate and
eliminate. If any problem persists please contact your distributor.

Check the LED is working correctly. If the number is not displayed, replace the
LED. If it still does not work, maintain or replace the display PCB.

Check whether the min/max value on LED accords with the set value. If there
is any difference and it has affected the normal welding process, adjust
accordingly.

Check fan for damage and correct rotation. If damaged, change immediately.
If the fan does not rotate after the arc welding machine is overheated, check
the blade is not obstructed. If the fan still does not rotate after eliminating the
above, push the blade in the direction the fan rotates. If the fan rotates
normally, the start capacity should be replaced. If not, change the fan.

Check whether the fast connector is loose or overheated. If so, it should be
fastened or changed.

Check the current output cable is not damaged. If so, it should be securely
insulated or replaced.

27

STEALTH DIGI-TIG 320 AC/DC PULSE

28

DATE MAINTENANCE CHECKS

Monthly Use dry compressed air to clear the inside of arc welding machine. Pay
examination particular attention to clear any dust on radiator, main voltage transformer,
inductance, IGBT module, the fast recover diode and PCB, etc.

Check the arc welding machine bolt. If loose, tighten. Replace if worn. Scrape
off any rust to ensure it works efficiently.

Quarterly Check the actual current accords with the displaying value. If not, they should
examination be reconfigured. The actual current value can be measured by the adjusted
plier-type ampere meter.

Annual Measure the insulating impedance among the main circuit, PCB and case.
examination If it is below 1MΩ, insulation may be damaged and should be repaired or
replaced.

5.2 Troubleshooting

• Before arc welding machines are despatched from the factory, they have already been
carefully checked. Do not allow anyone unauthorised to make any alterations to the
equipment.

• Maintenance work must be carefully undertaken. If any wire becomes loose or
misplaced, it may be a potential danger to the user.

• Only authorised professional maintenance personnel should overhaul the machine.

• Ensure the power switch is shut off before you switch on the mains supply to the
machine.

• If a problem persists and no authorised professional maintenance personnel is
available, contact your supplier.

If there are minor problems with the DIGI-TIG 200 AC/DC PFC MV welding machine,
consult the following chart:

S/N PROBLEM REASON SOLUTION

Power light is damaged or

Turn on the power source,

poor connection

Check and repair Pr7

1 fan works but power pilot

lamp is not on

Power transformer damaged Repair or change transformer

Control PCB fails Repair or replace control Pr4

Fan is blocked Clear blockage
Turn on the power source,
2 power lamp is on but fan Fan start capacitor damaged Change capacitor
does not work
Fan motor damaged Change fan

STEALTH DIGI-TIG 320 AC/DC PULSE

29

S/N PROBLEM REASON SOLUTION

3 Turn on the power source, lamp No power input Check if there is power supply

is not on and fan doesn’t work Inside machine fuse damaged Change fuse (3A)

4 Display number not clear LED is broken Change LED

Max value is not accordant Adjust potentiometer lmin on
(refer to 3.1) power board
5

Max and min value displayed
does not accord with set value

Min value is not accordant Adjust potentiometer lmax in

(refer to 3.1) current meter

6 No no-load voltage output

Machine is damaged Check main circuit and Pr4

(MMA)

Welding cable is not connected Connect welding cable to
with two output of welder welder’s output

Welding cable damaged Repair or change

Earth cable connection unstable Check earth cable connection

Welding cable is too long Use appropriate welding cable

Oil or dust on the workpiece Check and remove
7
Distance between tungsten

Reduce distance to approx

electrode and workpiece too
long

3mm

HF ignition board does not work Repair or change Pr8

Distance between charger too Adjust distance to approx
short 0.7mm

Welding gun switch Check welding gun switch,
malfunction control and aero socket

Gas cyliner is close or pressure
too low

Open or change gas cylinder

8 No gas flow (TIG)

Blockage in valve Remove blockage

Electromagnetic valve damaged Change valve

Spark on HF
igniting board

Arc cannot be
ignited (TIG)

No spark on
HF igniting
board

STEALTH DIGI-TIG 320 AC/DC PULSE

30

S/N PROBLEM REASON SOLUTION

Gas cylinder is closed or

Open or change gas cylinder

pressure is low

8 No gas flow (TIG)

Valve is blocked Remove blockage

Electromagnetic valve damaged Change valve

Gas test on front panel is on Turn off gas test

Valve is blocked Remove blockage

9 Gas flows continually

Electromagnetic valve damaged Change valve

Pre gas time adjustment knob
on front panel is damaged

Repair or change

Welding current cannot be

Front panel welding current

10

adjusted

potentiometer is not working repair or change potentiometer

efficiently or damaged

Power PCB is not working

Repair or change

efficiently
11 No AC output when ‘AC’ is
selected AC drive PCB is damaged Change PCB

AC IGBT module damaged Change module

Min value displayed not

Adjust potentiometer lmin on

accordant with actual value

power board

(refer to 3.1)
Welding current displayed is
12 not accordant with actual value Max value displayed not

Adjust potentiometer lmin on

accordant with actual value

power board

(refer to 3.1)

Welding current adjusted too low Increase welding current
Penetration of molten pool is
13 insufficient Arc is too long in welding
process

Use 2T operation

STEALTH DIGI-TIG 320 AC/DC PULSE

31

S/N PROBLEM REASON SOLUTION

Too much welding current Reduce welding current output

Overheat
protection

Working time too long Reduce duty cycle and process

Over-voltage

Power supply fluctuates

Use stable power supply

protection
14
Power supply fluctuates use stable power supply
Low voltage
protection Too many machines using Reduce number of machines
power at the same time in use

Over-current Incorrect current in main Check and repair main circuit

protection circuit and drive Pr6

Front panel
alarm lamp
is on

6 PARTS LIST

9012H-02 COVER
9012H-07 RECTIFIER
9012H-12 SWITCH
9012H-13 REAR PANEL
9012H-15 FAN
9012H-16 CAP PCB
9012H-17 POWER PCB
9012H-24 HALL CURRENT SENSOR
9012H-25 FRONT PANEL
9012H-26 DINSE SOCKET
9012H-27 FRONT PCB
9012H-28 12 PIN SOCKET
9012H-31 KNOB
9012H-34 HF PCB
9012H-39 POWER PCB
9012H-40 CONTROL PCB
9012H-41 FILTER PCB
9000H-42 SOLENOID VALVE

9012H-42 IGBT
9012H-47 MAIN PCB ASSEMBLY

7 MAIN ELECTRICAL DIAGRAM

STEALTH DIGI-TIG 320 AC/DC PULSE

MAINTENANCE AND TROUBLESHOOTING

§5.3 Electrical principle drawing

Specialised Welding Products Ltd

Unit 1, Farringdon Industrial Centre, Farringdon, Nr Alton, Hampshire GU34 3DD, UK
tel: [phone] • fax: [phone] • email: [e-mail]