A work instruction tells the person at the machine how to do one task, in the order they do it. A good one fits on a page, shows each step with a photo, marks the steps that protect quality, and says what to do when something is not right. It is written with the operator, kept at the point of use, and tested by having someone new follow it. If it lives in a binder in the office, it is for the auditor, not the operator.
Why this is where corrective actions die
You can run a perfect 8D, fix the PFMEA and update the control plan, and the problem still comes back, because the operator never saw any of it. The operator will not read the 8D. They will read a one-page instruction at their station if it is short and it helps them. The work instruction is where a corrective action reaches the floor.
What makes one work
- One task, one page. If it runs to three pages, split it, or the real steps are buried.
- Steps in the order they happen. Number them. Five to nine steps is plenty for one task.
- A photo or sketch for every step. People look at pictures before words. A photo of the correct way, and one of the wrong way where mistakes are common, beats a paragraph.
- Plain words the operator uses. The words on the floor, not the words in the procedure.
- Key points marked. Flag the steps that protect quality or safety and say why in a few words. “Dividers in the tote, or parts scratch.”
- What to do when it is not right. Who to call and what to do with the parts. This is the reaction from the control plan, in words the operator can act on.
- A revision and a date. So nobody works from an old copy.
How to write one
Watch the job being done
Stand at the station and watch the best operator do it. Note what they actually do, not what the old procedure says.
Write it with the operator
Draft it with them at the station. They will catch steps you missed and words they would never say.
Take the photos at the station
Use a phone. Show hands and parts in position. Crop to the part that matters and add an arrow or a circle.
Add the quality points from the control plan and the PFMEA
Every control that applies to this task should show up as a key point or a check step. If the corrective action added one, it goes here.
Add the reaction step
What to do and who to call when a check fails or the part looks wrong.
Run the stranger test
Give it to someone who has never done the job and watch them follow it without help. Wherever they stop or guess, the instruction is unclear. Fix it and test again.
Put it at the point of use and retire the old copy
On the station, in a sleeve, at eye level. Pull the old one the same day.
A made-up before and after
| Pack out instruction | |
|---|---|
| Before | Pack parts per customer packaging requirements and ensure no damage occurs during packing. Verify quantity prior to sealing. |
| After | 1. Place tote on the scale. 2. Insert the divider tray (photo). 3. Lay one housing in each pocket, sealing face up (photo, and a second photo of a housing laid face down with a red X). 4. Count: 24 per tote. 5. Close the lid, scan the tag. KEY POINT: dividers in every tote, or parts scratch. IF A TOTE HAS NO DIVIDERS: stop, tag the parts, call your supervisor. |
The second version is longer in words but shorter in thinking time, because the operator never has to decide what “no damage” means.
Mistakes that make an instruction useless
- Copying the procedure. A procedure describes the system. An instruction describes a task.
- Written by an engineer alone. The result describes the process on paper, not at the machine.
- Stored somewhere else. If the operator has to go and find it, they will not.
- No pictures. Wall-of-text instructions are skipped, then signed.
- No link to complaints. When a complaint changes a step, the instruction changes the same week, with the date.
- Never tested. An instruction nobody has tried to follow is a draft.
Field Book 1, chapter 6 walks through turning a corrective action into the one-page instruction. Pair it with the layered process audit, which checks that the instruction is at the station and being followed.
Questions people ask
How long should a work instruction be?
One page for one task. If it is longer, split the task.
What is the difference between a work instruction and a procedure?
A procedure describes how a process or system works across the organization. A work instruction tells one person how to do one task at one station.
Who should approve a work instruction?
The person who owns the process, with quality review where it carries quality or safety points. The operator who helped write it should see the final copy.
How do I keep instructions current?
Tie them to change control. Any process, tooling or corrective action change that affects the task triggers an update, with a revision and a date, and the old copy comes down.
Do I need photos?
You do not need them everywhere, but use them wherever a mistake is likely. A photo of the right way and the wrong way prevents more errors than an extra paragraph.