Work Instructions for Metal Fabrication Shops

Quality systems and welding codes

Most fab shops certify to ISO 9001 and add requirements by customer. ISO 9001 asks for controlled conditions in production, including the documented information people need, suitable equipment, competent people and validation of processes whose output cannot be fully checked afterwards. Welding is the classic example: a finished weld cannot be fully inspected without destroying it, so the procedure and the welder’s qualification carry much of the proof.

Structural and pressure work brings welding codes. AWS D1.1 covers structural steel welding in North America and requires qualified welding procedure specifications (WPS) and qualified welders. ISO 3834 sets quality requirements for fusion welding and is commonly asked for in Europe. Aerospace or defence work brings AS9100 on top. The weld symbols reference helps everyone read the drawing the same way.

Safety rules that belong in the instruction

Press brakes, shears, punches, lasers and welding cells carry serious hazards. In the United States, OSHA’s lockout/tagout standard requires energy-control procedures for servicing and maintenance, and machine guarding rules apply to operation. A work instruction should not copy the full safety procedure, but it should state the hazards at each step and point to the lockout/tagout procedure and the job safety analysis for that machine.

• Put guarding and hand-position warnings in the step where the hazard occurs.
• Say which tooling changes need lockout and which can be done with the machine in a safe mode.
• Keep the WPS number on the weld instruction so the welder knows which procedure applies.

The templates and tools that matter most

Example: Press brake setup and first-bend check

Example An excerpt from a work instruction at Ironwood Fabrication, a fictional fab shop. Part, tooling and dimensions are example values; use your own drawing, tooling chart and machine manual.

Download this example (.docx)

Tools, materials and PPE

• Punch and die from the tooling list on the setup sheet
• Protractor and tape measure, IDs on the setup record
• First-piece tag
• Cut-resistant gloves, safety glasses, steel-toe shoes

Steps

1. Lock out and change tooling. Lock out PB-2 following its LOTO procedure, then install the punch and die listed on the setup sheet.
   Key point: Verify zero energy by trying the controls before you reach into the tooling area.
   Reason: Tooling changes put hands between the punch and die.Safety: Never change tooling with the ram powered.
2. Load the program. Remove the lockout, load the program for 2210-14 and check the program revision against the setup sheet.
   Key point: The program revision must match the drawing revision on the header.
   Reason: An old program bends to an old drawing.
3. Bend a test blank. Bend a blank from the same material lot through all three bends in the programmed sequence.
   Key point: Follow the sequence; bending out of order can make bend 3 impossible.
   Reason: The sequence is set so the part clears the tooling.Safety: Keep hands outside the light curtain; support long parts from the side.
4. Check the first piece. Measure flange A height, each bend angle and the overall width, and record them with the gauge IDs.
   Key point: Adjust the back gauge or angle correction only, then bend a new blank.
   Reason: Measuring an adjusted part hides the setup error.
5. Release. Tag the approved first piece, sign the setup record and start the run.
   Key point: Keep the first piece at the brake until the job is complete.
   Reason: Gives operators a physical standard to compare against.

Acceptance criteria

• Flange A height and overall width within drawing tolerance
• All bend angles within drawing tolerance
• Setup record signed with program revision and gauge IDs

Common audit findings

These are the kinds of findings auditors and customers commonly write in this industry, with a way to prevent each one in the instruction itself.

• Welders are working to a procedure that is not identified, or that they are not qualified for. Put the WPS number on the weld instruction and check welder qualifications against it.
• Programs for brakes, lasers or punches are not under revision control. Name programs with the drawing revision and check them at setup, as in the Example above.
• First-piece checks are done but not recorded. Use a first piece inspection checklist with gauge IDs.
• Material certificates do not trace to the parts made. Record heat or lot numbers on the traveler at cutting and carry them through.
• Safety procedures exist but are not referenced where the hazard occurs. Add hazard notes and LOTO references to the step itself.
• Measuring tools on the floor are uncalibrated or unidentified. Log every tool in a calibration log and label it with its ID and due date.

Frequently asked questions

Sources

1. ISO 9001:2015 Quality management systems — Requirements, ISO
2. AWS D1.1 Structural Welding Code — Steel, American Welding Society
3. ISO 3834 Quality requirements for fusion welding of metallic materials, ISO
4. 29 CFR 1910.147 The control of hazardous energy (lockout/tagout), OSHA

Work instructions in other industries

• Aerospace job shopsAS9100, first article inspection, traceability and FOD control for build-to-print machine shops.
• Automotive tier 2/3 suppliersIATF 16949, control plans, PPAP and layered process audits for suppliers further down the chain.
• Medical device contract manufacturersISO 13485, the FDA QMSR, process validation and device history records for contract manufacturers.
• Plastics injection moldingProcess sheets, mold changes, material handling and first-shot approval for custom and captive molders.
• Electronics assemblyIPC workmanship classes, soldering requirements, ESD control and traceability for PCB and box-build assemblers.
• All industriesWhat changes in documentation and audits from one industry to the next.