How to Write a Manufacturing Work Instruction
A useful work instruction does not merely describe a process. It gives the intended user enough information to perform the task safely, consistently, and with a clear understanding of what acceptable work looks like.
Start with the user and the task
Define who will use the document, what task it covers, and the conditions under which it applies. A setup technician, machine operator, inspector, and engineer may need different levels of detail. A strong document is specific enough to guide the work without forcing the user to interpret long policy language.
Control the document before writing the steps
Include a document number, revision, effective date, department, owner, approver, and review cycle. The work instruction may be excellent, but it is still risky when employees cannot tell whether it is current.
Define purpose, scope, and prerequisites
The purpose explains why the instruction exists. The scope establishes where it applies and where it does not. Prerequisites identify training, machine condition, permits, materials, drawings, or upstream work that must be complete before Step 1.
Separate safety from the procedure without hiding it
List general PPE and hazards near the front of the document. Then repeat task-specific warnings directly beside the step where the exposure occurs. A warning placed three pages earlier is easy to overlook.
Write each step as an observable action
Begin with a verb: verify, install, measure, tighten, position, record, remove, or inspect. Identify the component and location. Include the tool, quantity, sequence, setting, or method when it matters. Avoid combining unrelated actions into a single paragraph.
Weak: “Set up the machine correctly.”
Stronger: “Install Fixture A on the locating pins, tighten the four M10 clamps to the approved torque, and verify the fixture sits flush against the base plate.”
Show what acceptable looks like
Expected results and acceptance criteria reduce interpretation. Use measurable limits when available. When a numerical limit is not appropriate, define an observable condition such as “guard fully seated with both latches engaged” rather than “guard looks good.”
Use photographs deliberately
A photo should answer a question: where is the component, what orientation is correct, what defect is unacceptable, or what completed work should look like? Crop unnecessary background and avoid using an image as a substitute for a critical written requirement.
Finish with verification and reaction
State the final checks required before release. Explain what to do when the process cannot be completed or the result is out of specification. “Notify supervisor” may be correct, but the document should also clarify whether the equipment, material, or product must be held.
Review the instruction on the shop floor
Have a qualified person perform the task using only the draft. Observe where they hesitate, ask questions, or rely on memory. Those moments identify the gaps the document must close.
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