Key takeaways
- Start with the cost of a failure at the line, not with the number of parts in the box.
- Dock check, document review, sampling and 100 per cent inspection are four different controls for four different risks.
- A sampling plan needs a standard, a sample size, an acceptance number and a reaction to a failure.
- The goods-in record has to name the lot, or the traceability chain breaks at the warehouse door.
Why goods-in inspection exists
Incoming inspection is the last planned check before a purchased part enters the line. Its job is to confirm that the shipment matches the purchase order and the drawing, and to catch a supplier escape before it becomes a production problem.
It is not a substitute for supplier control. If goods-in finds the same defect every month, the inspection is doing the supplier's job and the cost sits in your warehouse. The plan should catch exceptions, not compensate for a process that cannot hold the specification.
Classify the part before you write the plan
Classify each part on risk: what happens if it fails, how hard the feature is to inspect, the supplier's history, the volume and the cost of a bad batch. A part with a safety characteristic or a feature that is hidden after assembly deserves more than a count of boxes.
The classification should be written down and reviewed. A supplier that improves can move to a lighter control. A supplier with a new process, a new site or a change of ownership can move back up.
Four responses, not one default
Dock check covers identity, quantity, packaging and damage. Document review adds certificates and test reports. Sampling adds dimensional and functional checks on a defined sample. One hundred per cent inspection is for critical features or a supplier under containment.
Skip-lot is a fifth option for a stable part with a long clean history. It is a privilege, not a default, and it needs a written rule for returning to normal inspection after a failure.
| Band | Typical criteria | Goods-in response | Record |
|---|---|---|---|
| Critical | Safety or regulatory characteristic, or a failure that stops the line | Document review plus 100 per cent check of the critical feature | Full record with the gauge and the result for every piece |
| High | Tight tolerance, high value, new supplier or a recent escape | Document review plus sampling at a higher level | Lot record with the sample, the results and the certificate |
| Medium | Normal fit or function, stable supplier, moderate volume | Dock check plus periodic sampling | Lot record with the sample and the disposition |
| Low | Catalogue item, visual role, low failure cost | Dock check and certificate check | Receipt record with quantity and condition |
| Skip-lot | Long clean history, capable process, agreed in writing | Periodic check on a defined schedule | Schedule record and the trigger for return to normal |
The bands are a starting model. Set the criteria against the part, the supplier and the cost of a failure at your line.
What to check at the dock
The dock check is the cheapest control and the one most often done by rote. It should still confirm the things that make the rest of the inspection possible.
- Part number and revision match the purchase order and the drawing.
- Quantity, pack size and label match the delivery note.
- Packaging is intact, dry and free of damage that could affect the parts.
- Material certificate or certificate of conformity is present and names the lot.
- Plating or finish certificate matches the specified thickness and process.
- Traceability code and date code are readable and recorded.
- Shelf life, where relevant, is inside the agreed window.
Sampling needs a rule
Use a published sampling rule: ISO 2859-1 for AQL based plans, or a zero acceptance plan where any defect is unacceptable. Write the sample size, the acceptance number and the reaction to a failure. A plan that says to check a few parts is not a plan.
Do not switch between AQL and zero acceptance without saying so. The two answer different questions and carry different risks. The same lot can pass one and fail the other, and the argument afterwards is about the rule, not the part.
The goods-in record
The record should identify the lot, the supplier, the date, the inspector, the sample size, the characteristics checked, the gauge, the results and the disposition. It should reference the certificate and the purchase order so the evidence can be followed in both directions.
Keep the record with the lot, not in a separate file that cannot be matched later. A traceability chain breaks at goods-in if the inspection record does not name the lot that was checked. The same field also lets you answer a supplier query without searching three systems.
Quarantine, disposition and the feedback loop
Quarantine needs a marked area, a hold label, a system status and a named owner. The disposition options are accept, reject, rework, return to the supplier or use as is with written approval. Each one needs a reason and a signature.
Feed the result back into the supplier scorecard. A rejection that stays in the warehouse teaches nobody. Send the lot number, the defect, the measurement and the request for containment, then track the response against the next delivery.
Review the plan when the evidence changes
Review the plan when the supplier, the process, the drawing or the defect history changes. Also review it when inspection has found nothing for a long period. That can mean the supplier is good, or it can mean the plan is checking features that no longer matter.
A short annual review is enough for a stable part. A new part or a new supplier needs a review before the first shipment, not after the first rejection.
Inspection is a filter, not a fix
Every defect found at goods-in was made somewhere else. Record it, return it and use it to decide how much inspection the next lot needs.
Frequently asked questions
Do I need to inspect every incoming lot?
No. The response should follow the risk. Critical features may need every piece checked, while a stable low risk part may need a dock check and a periodic sample. The plan should state the rule and the trigger for a higher level.
Should incoming inspection use AQL or zero acceptance?
Use zero acceptance where any defect is unacceptable, such as a safety feature or a one-off assembly. Use an AQL plan where a defined defect rate is tolerable. Whichever you choose, write the standard, the sample size and the acceptance number into the plan.
What should the goods-in record contain?
The lot, supplier, date, inspector, sample size, characteristics, gauge, results, certificates and disposition. It should also reference the purchase order and the drawing revision so the record can be matched to the shipment and the specification.
Can a supplier be taken off incoming inspection?
Yes, through a documented skip-lot or dock check arrangement with a defined history and a return trigger. Removing inspection without a rule leaves no way to notice when the supplier's process changes.
Sources and further reading
- ISO 2859-1, Sampling procedures for inspection by attributes
- ANSI/ASQ Z1.4, Sampling procedures and tables for inspection by attributes
- ISO 9001:2015, Control of externally provided processes, products and services
Qumek Quality Desk
Quality team
The quality team responsible for first article inspection, PPAP packs, supplier audits and the records shipped with production parts.
Setting up goods-in inspection?
Send the part list, the drawing revisions and the current defect history. The quality desk will draft the risk bands and the sampling rules.
Send the part list