In this guide 6 sections
Number every emailed change on arrival. Log it, assess its effect on stock, open work orders and the next build, get internal and customer approval, then set an effectivity date. Nothing reaches the line until the revised BOM, program and work instruction are all released together, with the superseded copies pulled from the shared drive.
Log the notice the hour it lands
A customer writes that resistor R47 moves from one value to another, or that a new Gerber revision follows, and the email sits in a project engineer’s inbox. Two days later the line builds to the old revision and the boards need rework, which costs reflow and inspection time.
Give each notice a number on arrival. Record the customer, their own ECN reference, the assembly and revision affected, and who sent it, then attach the email and every file it brought along.
Reply with the number. Keep the reply short, because the customer now knows you have the change and you have a handle for every later question about it.
- Your change number and the customer’s ECN number
- Assembly number, old revision, new revision
- Received date and sender
- Attached BOM, Gerber, drawing or centroid files
- Named owner for the assessment
Assess what the change touches
Open the BOM comparison first. Mark every line that is added, removed or altered, because a swapped capacitor is simple while a new connector footprint may need a new stencil and bare board.
Then look at what you already hold. Stores may hold reels of the old part, kitted work orders may wait on the floor, and some boards may already be reflowed. Each pile needs its own call. Use up, rework, return or scrap.
Check lead times on new parts before promising a date, since a small change on paper can stall a build for weeks when the new part is on allocation.
- Stock on hand of removed parts, by reel and lot
- Open work orders and kits at each stage
- Purchase orders to amend or cancel
- Programs, stencils and test fixtures needing revision
Decide the effectivity before anyone signs
Effectivity says from which unit the change applies, and it can be a date, a work order number or a serial range. Pick the one your floor can actually follow.
Work order cut-in is usually cleanest. Orders released before it finish on the old revision, orders released after it use the new one, and mixed builds inside one order cause the worst confusion.
Write the rule on the change record itself. Never leave it verbal. If the customer wants the change on units already in progress, note the rework cost and get that agreed in writing before the first board is touched.
Approvals and release
Two sign-offs matter here. Internally, production, purchasing and quality each confirm their part is covered, and externally the customer confirms the effectivity, the cost and any first-article requirement.
Release only when the revised files replace the old ones everywhere, meaning the BOM in the system, the pick-and-place program, the work instruction and the inspection plan. Pull superseded copies off the shared drive.
Tell the line leads in person. A printed note at the kitting table beats an email they may not open, so walk the revision letter and the effectivity rule to each lead.
Close the loop on the first build
Flag the first work order built under the new revision for a first-article check, comparing the finished board against the change record line by line.
Send the customer the result. Close the record with the change number and the original email attached, so that next month, when someone asks why R47 changed, the answer takes ten seconds.
Change request tracking sheet
Each change gets a row whose columns hold change number, customer ECN reference, assembly, old and new revision, received date and owner. More columns record stock affected, open orders affected, the effectivity rule, sign-offs and release date, so a reviewer sees the whole change at once. Below the table sits a checklist of files to replace at release, namely the BOM, program, work instruction and inspection plan, each ticked off against the change number.
Open a blank worksheet to printQuestions owners ask
Should we accept changes sent only by email?
You can receive them that way, but log them under your own number, and ask for a formal ECN document for anything that alters form, fit or function.
What do we do with stock of the old part?
Decide per reel: use it up on orders before the cut-in, return it to the supplier if allowed, or hold it for the customer’s older revision. Record the decision on the change.
Who pays for rework on boards already built?
That depends on your contract, so put the question on the change record and get the customer’s answer in writing before any rework starts.
How do we stop the line using old files?
Replace files at release, remove superseded copies from shared folders, brief line leads directly, and print the revision on every traveller where operators cannot miss it.