A MIG welding setup work instruction tells the welder how to get from an idle machine to a production weld that meets the drawing: confirm the welding procedure and their own qualification, make the area and PPE safe, set up wire, gas and machine to the procedure, prepare the joint, prove the settings on a test piece, then weld and inspect. Below is a complete example for a fictional fabrication shop, with numbered steps, key points, reasons, safety callouts and acceptance criteria, plus a free .docx. Every setting in it is an example value, not a recommendation.
By Coplain Team
Last updated
What MIG welding setup involves
MIG welding, or gas metal arc welding (GMAW), feeds a solid wire electrode through a gun while a shielding gas protects the weld pool. The quality of the weld depends on a handful of settings working together: wire type and diameter, drive roll and liner condition, gas type and flow, voltage, wire feed speed, polarity, stickout and travel. Most of them can drift between shifts, and a weld can look acceptable on the surface while lacking fusion underneath. A setup instruction puts those settings in a fixed order and makes the welder prove them before the first production weld.
On code or customer work, the settings come from a welding procedure specification (WPS) qualified for the joint, and the welder must hold a qualification that covers it. The work instruction does not replace the WPS. It tells the welder where the WPS is, how to set the machine to it, and what to check. Read the symbols on the drawing first; the welding symbols chart helps if a callout is unclear.
Why safety callouts matter here
Welding brings arc radiation, fumes, heat, fire and electrical hazards into the same task. Safety rules in a block at the top are easy to skip, so this example puts each callout on the step where the hazard appears. Pair the instruction with a job safety analysis for the cell, and follow your site’s hot work and ventilation rules.
Example This work instruction is for Example Manufacturing Co., a fictional fabricator of steel frames. The wire, gas, flow, voltage and wire feed settings are example values from a fictional WPS, not recommendations. Use the values on your own qualified WPS.
Fillet welds on carbon steel brackets, 6 mm plate, flat and horizontal positions
WPS
WPS-112 rev 2 (fictional)
Owner
Welding engineering
Training
Welders qualified to WPS-112, listed on the skills matrix
Tools, materials and PPE
MIG power source and gun, set up for the wire on the WPS
Solid wire ER70S-6, 0.9 mm (example value from the WPS)
Shielding gas 75% argon / 25% CO2 with flowmeter (example value from the WPS)
Wire brush, grinder with flap disc, anti-spatter, fillet weld gauge
Welding helmet with the shade on the WPS or PPE matrix, flame-resistant jacket, leather gloves, safety glasses, safety boots
Steps
Confirm the WPS and your qualification. Find the WPS named on the traveler and check your name is on the qualified-welder list for it. Key point: If you are not qualified to that WPS, or the WPS is not at the station, stop and call the lead. Reason: Welding outside a qualified procedure or qualification can make the weld unacceptable whether or not it looks good.
Make the area safe. Clear combustibles from the cell, check the fume extraction is running, close the weld curtains and check the fire extinguisher is in place. Key point: Keep combustibles well clear of the work, at the distance set by your hot work rules. Reason: Sparks and spatter travel further than they seem to, and fumes need to be captured at the source.Safety: Wear all PPE on the list before striking an arc. Do not weld in wet conditions or while standing in water.
Inspect the machine and leads. Check the gun, liner, contact tip, nozzle, work lead and clamp. Replace a worn contact tip and clean spatter out of the nozzle. Key point: Work clamp on clean bare metal as close to the joint as practical. No cracked insulation on any lead. Reason: A poor ground or worn tip causes an unstable arc; damaged insulation is a shock hazard.Safety: Switch the power source off before changing the contact tip or liner.
Load and check the wire. Check the wire type and diameter against the WPS. Fit drive rolls and contact tip for that diameter, feed the wire through and set the drive roll tension. Key point: Set tension just high enough that the wire feeds without slipping when lightly held back at the tip. Reason: Wrong rolls or too much tension deforms the wire and causes erratic feeding and burnback.Safety: Keep fingers away from the drive rolls and never point the gun at anyone while feeding wire.
Set up the shielding gas. Check the cylinder label against the WPS. Open the valve, set the flowmeter to 14–16 L/min (example value from the WPS) with the trigger pressed, and listen for leaks. Key point: Set flow with gas flowing, not static. Shield the cell from drafts and fans. Reason: Too little gas, or gas blown away by a draft, causes porosity.Safety: Chain or strap cylinders upright. Open the valve slowly and stand to the side of the regulator.
Set the machine to the WPS. Set polarity, voltage and wire feed speed to the WPS: DCEP, 20 V and 7.5 m/min (example values). Key point: Set every parameter to the WPS value, inside its stated range. Note the actual settings on the traveler. Reason: These settings control penetration and bead shape; adjusting by sound alone drifts from the qualified procedure.
Prepare and fit up the joint. Remove mill scale, rust, oil and paint from the weld area. Clamp the parts in the fixture and check fit-up against the drawing. Key point: Clean metal at the weld and on both sides of it. Gap and alignment within the drawing or WPS limits. Reason: Contamination causes porosity, and a poor fit-up changes the weld size and fusion.Safety: Wear a face shield over safety glasses when grinding, and check the disc is rated for the grinder speed.
Weld a test piece. Weld a fillet on a scrap coupon of the same material and thickness. Check the bead, then break or cut it if your procedure asks for it. Key point: Bead smooth and even, no porosity, wetting into both members, size measured with the fillet gauge. Reason: Proving the settings on scrap costs one coupon; finding a bad setting on the part costs the part.
Weld and inspect the production part. Weld the joints in the order on the drawing or traveler. Clean spatter, then inspect each weld visually and with the fillet gauge. Key point: Inspect every weld before the part leaves the cell. Mark and hold any weld you are not sure about. Reason: Defects are easiest to repair before the part is painted or assembled.Safety: Treat all metal in the cell as hot. Use pliers or gloves to handle parts.
Acceptance criteria
Welder qualified to the WPS on the traveler; settings recorded and inside the WPS ranges.
Weld size measured with a fillet gauge and at least the size on the drawing (example: 5 mm fillet).
No cracks, no visible porosity and no incomplete fusion at the weld toes.
Undercut, spatter and profile within the limits of the code or specification on the drawing.
Area left safe: gas cylinder valve closed, power off, combustibles still clear.
How to adapt this example
Copy the steps into the blank work instruction template, or edit the .docx above. Start from your WPS and your cell. Copy the parameters from the WPS into the instruction by reference, not by retyping ranges that can go out of date; the safest wording is “set to WPS-xxx”. Then follow the method in how to write a work instruction.
Change the material, thickness, positions and transfer mode to match your WPS. Aluminum and stainless need different wire, gas and drive setup.
Take the acceptance limits from the code or customer specification on your drawing. Do not copy limits from another code.
Check the plate thickness against your drawing with the sheet metal gauge chart when the drawing calls it out by gauge.
Keep welder qualifications current on a skills matrix so step 1 is quick to check.
Common mistakes
Copying WPS ranges into the instruction. Reference the WPS number and revision so the instruction never disagrees with the qualified procedure.
No test weld. Prove the settings on a scrap coupon every setup and after any change of wire, gas or machine.
Ground clamp on painted or rusty metal. Clamp to clean bare metal close to the joint.
Setting gas flow with no gas flowing. Set flow with the trigger pressed and gas moving through the gun.
Safety rules only in a header block. Put each callout on the step where the hazard occurs.
Inspection by eye only. Measure weld size with a fillet gauge and record it.
Frequently asked questions
What is the difference between a WPS and a welding work instruction?
A WPS is the qualified procedure that sets the welding variables for a joint. A work instruction tells the welder how to set up and work to that WPS at a specific station.
Are the settings in this example safe to use?
They are example values for a fictional WPS, not recommendations. Use the settings on your own qualified WPS and the equipment maker’s manual.
Why does a MIG weld get porosity?
Common causes include too little or too much gas flow, drafts, contaminated base metal or wire, and a blocked or spatter-filled nozzle.
Who inspects the welds?
Your quality plan decides. Often the welder does a visual and gauge check, and a qualified inspector checks welds that the code or customer requires.
Do I need a separate safety document?
Usually yes. A job safety analysis and your hot work permit rules cover hazards in more depth; the work instruction puts the key ones at the right step.
Sources
AWS D1.1, Structural Welding Code — Steel, American Welding Society
ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, American Welding Society
29 CFR 1910 Subpart Q, Welding, Cutting and Brazing, U.S. Occupational Safety and Health Administration
AWS A5.18, Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding, American Welding Society
Generate yours automatically from your existing docs
Turn your real work instruction into an audit-ready job aid in Coplain. Upload your welding procedure and Coplain drafts a station job aid that points to your WPS instead of retyping it.