Weldclass Weldforce 155M User manual

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 1
Weldforce 155M
Weldforce 175MST
Edition 2.6
OPERATING INSTRUCTIONS
 IMPORTANT!
To qualify for extended warranty, you must register within 30 days of purchase. See inside for details.
Read these Operating Instructions Completely before attempting to use this machine. Save this manual and
keep it handy for quick reference. Pay particular attention to the safety instructions we have provided for
your protection. Contact your distributor if you do not fully understand anything in this manual.

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2© Weldclass 2020 | E.&O.E.
Congratulations & thank you for choosing Weldclass!
The Weldforce range from Weldclass provides market leading value, features and durability.
Register Your Warranty Now
To qualify for an extended warranty, you must register within 30 days of purchase.
Full details on warranty period and terms can be found at www.weldclass.com.au/WarrantyInfo
Please register your warranty now by going to:
www.weldclass.com.au/weldforcewarranty
You will need;
a) A copy of your purchase invoice / receipt.
b) Your machine serial number which can be found on the technical data plate on the back of the
machine, or on the outside of the box that your machine came in.
Satisfaction Guarantee
For full details on our satisfaction guarantee, refer to www.weldclass.com.au/mbg

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 3
1CONTENTS
1CONTENTS...............................................................................................................................................3
2BASIC SPECIFICATIONS ............................................................................................................................7
3KNOW YOUR MACHINE...........................................................................................................................8
3.1 Machine Front................................................................................................................................8
3.2 Machine Rear .................................................................................................................................8
3.3 Control Panel..................................................................................................................................9
3.4 Symbols chart...............................................................................................................................10
4CONTROLS EXPLAINED..........................................................................................................................11
4.1 Weld Process Selection (Weldforce 175MST only).......................................................................11
4.1.1 MIG/MAG Process:...................................................................................................................11
4.1.2 MMA (Stick) Process: ...............................................................................................................11
4.1.3 TIG Process:..............................................................................................................................11
4.2 Welding Power Output Control....................................................................................................11
4.3 Inductance Control (MIG/MAG only)...........................................................................................12
4.4 Arc Force Adjustment (MMA/Stick only) (Weldforce 175MST only) ...........................................12
4.5 Error/Over Temperature Indicator Light ......................................................................................13
5POWER SUPPLY .....................................................................................................................................13
5.1 Electrical Connection....................................................................................................................13
5.2 Extension Leads............................................................................................................................13
5.3 Generator Use..............................................................................................................................13
5.3.1 Generator Size..........................................................................................................................13
5.3.2 Generator Quality & Warranty Limitations..............................................................................14
5.3.3 3 Golden Rules of Generator use.............................................................................................14
6OPERATING ENVIRONMENT..................................................................................................................14
6.1 Location........................................................................................................................................14
6.2 Ventilation....................................................................................................................................14
7BASIC OPERATION.................................................................................................................................15
7.1 MIG Welding.................................................................................................................................15
7.1.1 Fitting Wire Spool.....................................................................................................................15
7.1.2 Loading Wire Feeder................................................................................................................16
7.1.3 Gasless Welding Setup.............................................................................................................18
7.1.4 Gas MIG Welding Setup ...........................................................................................................19
7.1.5 Additional Setup for MIG welding with Aluminium (Weldforce 175MST only)........................20
7.1.6 Settings for MIG Welding .........................................................................................................20
7.1.1 Drive Rollers & Torch Liners for different Wires.......................................................................21
7.2 Stick (MMA) Welding Operation (Weldforce 175MST only).........................................................22

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4© Weldclass 2020 | E.&O.E.
7.3 Lift TIG Operation (Weldforce 175MST only)................................................................................23
8ACCESSORIES, SPARE PARTS & CIRCUIT DIAGRAMS..............................................................................24
8.1 MIG Torch and Spares for Weldforce 155M:................................................................................24
8.2 MIG Torch and Spares for Weldforce 175M:................................................................................25
8.3 TIG Torch and Spares (Optional Extra for Weldforce 175MST only):............................................26
8.4 Optional Accessories....................................................................................................................27
8.5 Drive Rollers .................................................................................................................................27
8.6 Machine Spare Parts: ...................................................................................................................28
8.7 Primary Schematic Circuit Diagram..............................................................................................31
9CARE & MAINTENANCE.........................................................................................................................32
9.1 Keep your Welding Machine in Top Condition.............................................................................32
9.2 Storing the Welder .......................................................................................................................32
10 GENERAL GUIDE TO WELDING .........................................................................................................33
10.1 Duty Cycle Rating .........................................................................................................................33
10.2 Choosing a Welding Process – MIG, Stick or TIG?........................................................................33
10.2.1 The Stick (MMA) Process .....................................................................................................33
10.2.2 The TIG Process....................................................................................................................34
10.2.3 The MIG Process ..................................................................................................................34
10.3 Joint Preparations ........................................................................................................................35
11 MIG BASIC WELDING GUIDE.............................................................................................................37
11.1 MIG Basic Welding Techniques ....................................................................................................37
11.2 Gas Metal Arc Welding (GMAW)..................................................................................................37
11.3 Flux Cored Arc Welding (FCAW) ...................................................................................................37
11.4 Position of MIG Torch...................................................................................................................38
11.5 Distance from the MIG Torch Nozzle to the Work Piece..............................................................38
11.6 Travel Speed .................................................................................................................................38
11.7 MIG Welding (GMAW) Variables..................................................................................................39
11.7.1 Preselected Variables...........................................................................................................39
11.7.2 Primary Adjustable Variables...............................................................................................39
11.7.3 Secondary Adjustable Variables...........................................................................................39
11.8 Establishing the Arc and Making Weld Beads ..............................................................................41
11.9 MIG Output Settings ....................................................................................................................41
11.9.1 Changing to a different welding wire...................................................................................41
11.10 Welding wire Size Selection .....................................................................................................41
11.11 MIG Welding Troubleshooting .................................................................................................42
11.11.1 Porosity Problems................................................................................................................42
11.11.2 Wire Feed Problems.............................................................................................................43
11.11.3 Weld Quality Problems ........................................................................................................44
12 STICK (MMA) BASIC WELDING GUIDE ..............................................................................................46

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 5
12.1 Size of Electrodes .........................................................................................................................46
12.2 Storage of Electrodes ...................................................................................................................46
12.3 Electrode Polarity.........................................................................................................................46
12.4 Effects of Stick (MMA) Welding on Various Materials..................................................................46
12.4.1 High Tensile and Alloy Steels................................................................................................46
12.4.2 Manganese Steels ................................................................................................................46
12.4.3 Cast Iron...............................................................................................................................46
12.5 Types of Electrodes ......................................................................................................................47
12.5.1 MILD STEEL: .........................................................................................................................47
12.5.2 CAST IRON:...........................................................................................................................47
12.5.3 STAINLESS STEEL: .................................................................................................................47
12.6 Suggested Settings for Typical Stick (MMA) Applications ............................................................47
12.7 MMA Welding Techniques ...........................................................................................................48
12.7.1 A Word for Beginners...........................................................................................................48
12.7.2 The Welder...........................................................................................................................48
12.7.3 Striking the Arc.....................................................................................................................48
12.7.4 Arc Length............................................................................................................................49
12.7.5 Rate of Travel .......................................................................................................................49
12.8 Making Welded Joints ..................................................................................................................50
12.8.1 Butt Welds............................................................................................................................50
12.8.2 Fillet Welds...........................................................................................................................51
12.8.3 Vertical Welds ......................................................................................................................52
12.8.4 Overhead Welds...................................................................................................................53
12.9 MMA (Stick) Troubleshooting ......................................................................................................54
13 TIG BASIC WELDING GUIDE..............................................................................................................56
13.1 TIG Electrode Selection and Preparation .....................................................................................56
13.1.1 Electrode Polarity.................................................................................................................56
13.1.2 Preparing Tungsten for DC Electrode Negative (DCEN) Welding .........................................57
13.1.3 Shielding Gas for TIG Welding..............................................................................................58
13.1.4 Typical TIG Welding Settings................................................................................................58
13.2 TIG Welding Troubleshooting.......................................................................................................59
14 KNOWLEDGE & RESOURCES.............................................................................................................60
15 SAFETY..............................................................................................................................................60
15.1 Store and Retain this Manual.......................................................................................................60
15.2 Important Safety Information ......................................................................................................60
15.3 Welding Operation.......................................................................................................................60
15.4 Welding Safety Instructions & Warnings......................................................................................62
15.4.1 Personal Safety.....................................................................................................................63
15.4.2 Arc Rays can Burn Eyes and Skin..........................................................................................63

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6© Weldclass 2020 | E.&O.E.
15.4.3 Noise Can Damage Hearing .................................................................................................63
15.4.4 Work Environment Safety....................................................................................................64
15.4.5 Electricity Can Kill.................................................................................................................64
15.4.6 Fumes And Gases.................................................................................................................65
15.4.7 Fire & Explosive Risks...........................................................................................................66
15.4.8 Sparks & Hot Metal..............................................................................................................66
15.4.9 Gas Cylinders........................................................................................................................67
16 WARRANTY.......................................................................................................................................67
16.1 Warranty Information ..................................................................................................................67

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 7
2BASIC SPECIFICATIONS
Description
Weldforce 155M
Weldforce 175MST
Part Number
WC-155M
WC-175MST
Dimensions of Power Source (L x
W x H)
450 x 235 x 370mm
450 x 235 x 370mm
Weight of Power Source
9.3kg
11kg
Standard
AS 60974.1
AS 60974.1
Power Supply
230V +/- 15% 50hz Single Phase
Factory Fitting Supply Plug Rating
10A
10A
Effective Input Current (I1eff)
9A
10A
Maximum Input Current (I1max)
18A
22A
Protection Class
IP23
IP23
MIG Welding
Welding Current Output
20 – 115A (max 150A)
20 – 140A (max 170A)
Welding Voltage Output
15 – 19.8V
15 – 21V
Duty Cycle
115A / 19.8V @ 20%
65A / 17.3V @ 60%
50A / 16.5V @ 100%
140A / 21V @ 20%
80A / 18V @ 60%
60A / 17V @ 100%
Nominal Open Circuit Voltage
44V
44V
Spool Size
100mm (1kg) & 200mm (4.5kg or 5kg)
MIG Wire Sizes
0.6, 0.8, 0.9mm
0.6, 0.8, 0.9, 1.0mm
Stick (MMA) Welding
Welding Current Output
N/A
20 – 120A (max 150A)
Duty Cycle
120A / 24.8V @ 30%
80A / 23.2V @ 60%
60A / 22.4V @ 100%
Nominal Open Circuit Voltage
44V
MMA Electrode Size
1.6 – 3.2mm
TIG Welding
Welding Current Output
N/A
20 – 120A (max 150A)
Duty Cycle
120A / 14.8V @ 30%
80A / 13.2V @ 60%
60A / 12.4V @ 100%
Nominal Open Circuit Voltage
44V
TIG Tungsten Size
1.6 – 2.4mm
Table 1
For full machine specifications, refer to technical data plate on back of machine – or go to:
http://www.weldclass.com.au/155M / www.Weldclass.com.au/170MST

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8© Weldclass 2020 | E.&O.E.
Figure 2
3KNOW YOUR MACHINE
3.1 Machine Front
1. Control panel
2. MIG Torch
3. Earth Lead
4. Euro MIG Torch Connection
5. Positive Dinse Socket
6. Negative Dinse Socket
7. Torch Polarity Change Tail
3.2 Machine Rear
8. Mains Power Switch
9. Gas Inlet Connection
10. 240V AC Mains Power Input Lead
Weldforce 155M Figure 1 Weldforce 175MST

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 9
3.3 Control Panel
1. Power Indicator LED
2. Thermal Overload / Error Indicator LED
3. Output Knob
4. Inductance (/Arc Force) Knob
5. Process Selector Knob
Figure 3
Weldforce 155M
Weldforce 170M

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10 © Weldclass 2020 | E.&O.E.
3.4 Symbols chart
I
Power On
O
Power Off
Power On
Indication
ꝇ
Fault Indication
Caution / Hazard
Read Instruction
Manual
Material
Thickness
Wire Feed
MIG Inductance
Single phase
Inverter power
source DC
MIG (GMAW)
Function
Stick/MMA
(SMAW) Function
TIG (GTAW)
Function
Power Supply
Connection
Single Phase
Direct Current
(DC)
–
Negative
+
Positive
Hertz (cycles/sec)
Duty Cycle
Amperage
(Current)
Voltage
Electrical Hazard
Toxic Gas/Fume
Hazard
Explosive Hazard
Eye Injury Hazard
Pacemaker
Interference
Warning
Do not suspend
from handle
Radiation Hazard
Table 2

4CONTROLS EXPLAINED
4.1 Weld Process Selection (Weldforce 175MST only)
1. Rotate ‘Process Selector Knob’ (5) to desired position.
4.1.1 MIG/MAG Process:
In this mode the Inductance Knob adjusts inductance (arc focus) and the Output Knob adjusts target
output (power).
4.1.2 MMA (Stick) Process:
In this mode the Inductance Knob adjusts arc force and the Output Knob adjusts target amperage
output.
4.1.3 TIG Process:
In this mode the Inductance Knob is disabled and the Output Knob adjusts target amperage output.
4.2 Welding Power Output Control
This output power of the weld is controlled by the Output Knob.
In MIG/MAG process mode the wirespeed and voltage of the arc are both adjusted together as this is a
Synergic technology machine.
In MMA (Stick) & TIG process modes (Weldforce 175MST only) this Output Knob adjusts the amperage
output.
Figure 4

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12 © Weldclass 2020 | E.&O.E.
4.3 Inductance Control (MIG/MAG only)
This setting changes the MIG waveform to simulate changing the inductance of the welding circuit.
Inductance controls the rate of the current rise and fall as the welding wire contacts the workpiece (known
as a short circuit).
More inductance increases the short circuit time and decreases the short circuit frequency rate. This causes
a wider and more penetrating arc, often with better edge wetting, useful for thicker weld joints.
Less inductance will create a narrow more focused arc. This effect can also be used to fine tune the arc to
produce less spatter. This is often effective on thin materials.
Wire speed, wire size and type, shielding gas will all change the effect that the inductance setting has on
the welding arc.
To adjust inductance, rotate the Inductance Knob.
Figure 5
4.4 Arc Force Adjustment (MMA/Stick only) (Weldforce 175MST only)
Arc Force setting is adjustable from 0 – 100%. Sometimes called ‘Dig’ or ‘Arc Control’. A Stick welder is
designed to produce constant output current (CC). This means with different types of electrode and arc
length; the welding voltage varies to keep the current constant. This can cause instability in some welding
conditions as Stick welding electrodes will have a minimum voltage they can operate with and still have a
stable arc.
Arc Force control boosts the welding power if its senses the welding voltage is getting too low. The higher
the arc force adjustment, the higher the minimum voltage that the power source will allow. This effect will
also cause the welding current to increase. 0 is Arc Force off, 100% is maximum Arc Force. This is practically
useful for electrode types that have a higher operating voltage requirement or joint types that require a
short arc length such as out of position welds.

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 13
4.5 Error/Over Temperature Indicator Light
Error/Over Temperature Indicator Light illuminates yellow to indicate that welding current has stopped
for one of the following reasons:
•Thermal Protection: when duty cycle is exceeded and thermal protection is activated. When
thermal protection is activated, welding output will be disabled until machines cools
sufficiently and overload indicator lamp goes out.
•Power Supply Voltage Protection: the machine will stop functioning if the input power
supply voltage exceeds unsafe limits (over 15%).
•Short Circuit Protection: automatically shuts down the welding machine if there is short
circuit in the welding circuit (e.g. torch touch the job or stick electrode sticks to the job).
This may also activate if there are electronic circuit failure issues.
5POWER SUPPLY
5.1 Electrical Connection
The Weldforce 155M & 175MST machines are designed to operate on a 10A 240V AC power supply.
5.2 Extension Leads
If an extension cord must be used, it should be minimum cable core size 2.0mm2 for length of up to
10m, or minimum 2.5mm2 for lengths over 10m.
Using extension leads of over 50m is not recommended.
5.3 Generator Use
This machine is designed with generator use in mind and incorporates wide voltage tolerance and
intelligent voltage sensing technology to provide maximum protection from power fluctuations that
can occur with motor generators.
5.3.1 Generator Size
Generator size should be not less than 7kva. A 7kVa generator may not provide enough power to
enable full output and duty of this welder. However, it should provide sufficient power to enable
the majority of applications for which this machine was designed.
To enable full output and duty cycle of this welder a minimum recommended generator size is
minimum 10kVa.
Figure 6

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14 © Weldclass 2020 | E.&O.E.
5.3.2 Generator Quality & Warranty Limitations
Avoid using poor, low quality generators as these have the greatest risk of power spikes etc. A
suitable quality generator should have a THD (total harmonic distortion) rating of no more than 6%.
Most reputable generator suppliers will be able to specify the THD ratings on their product.
Any damage caused by poor quality generator power supply or incorrect use is not covered under
warranty.
5.3.3 3 Golden Rules of Generator use
When running an inverter welder off a generator there are 3 VERY IMPORTANT Golden Rules that
MUST be followed:
1. Do NOT plug welder into generator until AFTER generator has been started up and is running
smoothly
2. UNPLUG welder from generator BEFORE shutting generator down/turning generator off
3. NEVER let your generator run out of fuel whilst the welder is plugged in.
Following these Golden Rules will significantly reduce the risk of any damage resulting from
generator power supply.
6OPERATING ENVIRONMENT
6.1 Location
The machine has electrical components and control circuit boards which may be damaged by excessive
moisture, dust and dirt, so a clean and dry operating environment is important for reliable product life.
The enclosure design of this power source meets the requirements of IP23S as outlined in AS60529.
This provides adequate protection against solid objects (greater than 12mm), and direct protection
from vertical drops. Under no circumstances should the unit be operated or connected in a micro
environment that will exceed the stated conditions. For further information please refer to AS 60529.
6.2 Ventilation
Adequate ventilation is required to provide proper cooling for the machine. Ensure that the machine
is placed on a stable level surface where clean cool air can easily flow through the unit.

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 15
7BASIC OPERATION
7.1 MIG Welding
WARNING! Before changing the feed roller or wire spool, ensure that the mains
power is switched off.
7.1.1 Fitting Wire Spool
1. Open the wire feeder compartment door.
2. Remove the Tension Nut & Spring
3. Remove Flange/Spacer
4. Fit the wire spool to the Spool Post Bolt, ensuring that the wire spool is position so that the wire
will exit from bottom of spool.
5. Replace the Flange/Spacer – as per orientation shown below (orientation is different for
100mm/1kg vs 200mm/5kg spools)
6. Replace spring & Tension Nut.
Note: Adjust tension so that the spool can rotate freely, but does not continue to rotate (free-
wheel) once the wire feed stops.
Figure 7

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16 © Weldclass 2020 | E.&O.E.
7.1.2 Loading Wire Feeder
1. Set welding process to ‘MIG/MAG’ (Weldforce 175MST only)
2. Release the Wire Feed Tension Arm by pivoting the Tension Lever towards you from the vertical
‘locked’ position.
3. Remove Drive Roller Retaining Cap & Drive Roller
4. Check the wire Drive Roller groove matches the selected MIG wire type and size. The drive roller
will have two different sized grooves; the size of the groove in use is stamped on the side of the
drive roller.
Weldforce 155M: The serrated (knurled) groove side of the drive roller can be used for both
Gasless MIG welding and Solid steel MIG wire in either 0.8 or 0.9mm. The smooth ‘V’ groove side
is for 0.6mm solid steel wire.
Weldforce 175MST: For flux cored ‘soft’ wire, such as that used in gasless MIG welding, the drive
roller groove has a serrated profile (known as knurled). For solid ‘hard’ MIG wire, the drive roller
groove used has a ‘V’ shaped profile. For Aluminum MIG wire, the drive roller required has a ‘U’
shaped groove.
5. Fit correct drive roller & replace retaining cap
6. Manually feed the wire through the Wire Inlet Guide, through the Drive Roller groove and into
the Wire Outlet Tube.
7. Ensuring that the wire is correctly seated in the drive roller groove, replace the Wire Feed Tension
Arm and lock it into place by pivoting the Wire Feed Tension Lever back to the vertical position.
8. Adjusting wire feed tension by winding the Tension Lever Knob. Clockwise will increase tension,
anticlockwise will decrease drive tension.
TIP! Ideal tension is as little as possible, while maintaining a consistent wire feed with
no drive roller slippage.
Check all other causes of excess wire feeding friction causing slippage first, such as;
incorrect contact tip size, damaged contact tip, blocked/damaged torch wire guide
liner, incorrect/worn drive roller, before increasing wire feed tension.
WARNING! The use of excessive feed tension will cause rapid and premature wear of
the drive roller, the support bearing and the drive motor/gearbox.
9. Connect the MIG Torch to the MIG torch Euro Connector on the front of the machine (Weldforce
175MST only). Secure by firmly hand tightening the threaded collar on the MIG Torch connector.
10. Check that the correct matching MIG wire, drive roller and MIG torch tip are fitted.
11. Connect the machine to suitable mains power using the mains input power lead. Switch the
mains power switch to ‘I’ (On) to power up the machine.
12. You are now ready to feed the wire through the torch. With the wire feeder cover open, pull the
trigger on the MIG torch to check that the wire is feeding smoothly through the feeder and into
the torch.
13. Remove the contact tip from the torch and lay the torch out as straight as possible.
14. Pull the trigger on the torch until the wire feeds out through the end of the MIG torch.
15. Replace the tip on the MIG torch and trim off any excess wire.
WARNING! DO NOT touch the wire while it is feeding as it is electrically live and you
risk electrocution or injury.

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 17
Figure 8
Tension Arm
Tension Lever & Knob
Drive Roller
Wire Inlet Guide Tube
Drive Roller Retainer Cap
Wire Outlet Tube

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18 © Weldclass 2020 | E.&O.E.
7.1.3 Gasless Welding Setup
Weldforce 155M
1. Open the wire feeder compartment door.
2. Connect the Torch Polarity Cable (coming from bottom of machine) to the Negative Dinse Socket.
Ensure the connection is tight and firm.
3. Connect the Earth Polarity Cable (coming from top of machine) to the Positive Dinse Socket.
Ensure the connection is tight and firm.
4. Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
Note: if this connection is not made, there will be no electrical connection to the welding torch!
Figure 9
Weldforce 175MST
1. Connect the earth cable quick connector to the Positive Dinse Socket.
2. Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
3. Connect the Torch Polarity Change Tail to the Negative Dinse Socket.
Note: if this connection is not made, there will be no electrical connection to the welding torch!
Figure 10

Weldforce 155M & 175MST
© Weldclass 2020 | E.&O.E. 19
7.1.4 Gas MIG Welding Setup
NOTE: Gas MIG welding will require a gas cylinder. (Argon mix or CO2)
1. Connect the gas regulator to a gas cylinder (not included with machine) and connect the gas hose
from the regulator to the gas inlet connection on the rear of the machine. Ensure all hose
connections are tight and clamped with the hose clamps provided.
2. Open gas cylinder valve and adjust regulator. Pull the trigger on the MIG torch to initiate flow of
gas through the welding torch. Flow should be between 10-25L/min depending on application.
Weldforce 155M
3. Open the wire feeder compartment door.
4. Connect the Torch Polarity Cable (coming from bottom of machine) to the Positive Terminal.
Ensure the connection is tight and firm.
5. Connect the Earth Polarity Cable (coming from top of machine) to the Negative Dinse Socket.
Ensure the connection is tight and firm.
6. Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
Note: if this connection is not made, there will be no electrical connection to the welding torch!
Figure 11
Weldforce 175MST
3. Connect the earth cable quick connector to the Negative Dinse Socket.
4. Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
5. Connect the Torch Polarity Change Tail to the Positive Dinse Socket.
Note: if this connection is not made, there will be no electrical connection to the welding torch!
Figure 12

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20 © Weldclass 2020 | E.&O.E.
7.1.5 Additional Setup for MIG welding with Aluminium (Weldforce 175MST only)
Welding with aluminium provides a unique challenge, due to the low column strength and surface
friction of the wire. This causes the wire to deform more as it is pushed through the feed mechanism
and the torch wire delivery liner, greatly increasing friction. Because good MIG welding results are
dependent on a smooth wire feed, certain changes must be made to the wire feed system to minimise
friction caused issues.
1. A shorter MIG Torch will minimize friction and issues. If possible limit length to no longer than 3m
2. Replace the liner in the MIG Torch with a special Graphite/Teflon/PVC liner (rather than the
conventional steel liner). The Weldclass Universal Graphite liner kit is recommended (P3-CTUL09)
3. Choose the largest dimeter wire possible that can be used by your machine for your application.
(Ideally 1.0mm or above)
4. Ensure the wire drive system is fitted with the correct size U-groove drive roller to suit the wire
being used.
5. Ensure specific Aluminium contact tip to suit chosen wire (or a standard tip in one size oversize,
e.g. 1.0mm aluminium wire, use standard 1.2mm contact tip).
TIP! For above reasons, it is quite common for operators to have an extra MIG torch
specifically set up for aluminium use, if the machine is used for welding steel as well.
7.1.6 Settings for MIG Welding
1. Follow above steps for either ‘Gasless Welding Setup’ or ‘Gas MIG Welding Setup’ (whichever is
relevant)
2. Set welding process selector to ‘MIG’ (Weldforce 175MST only)
3. Rotate Output Knob to choose output power. (Refer to Charts below)
4. Rotate Output Knob
5. Inductance (/Arc Force) Knob to fine tune the desired setting. This can be modified to fine tune
the arc characteristics to suit your exact welding application. (Refer to Charts below)
Weldforce 155M
Table 3
*Use chart as guide only, as optimal settings will vary with weld joint type and operator technique.