Incoming inspection checklist: what to check before material hits your line
A truck arrives at your gate with 4,000 machined bushes from a new supplier. Production wants them on the line by second shift. Your stores team has already started unloading. If your incoming inspection is a quick glance and a signature, you will find the undersize bores three weeks later — inside finished assemblies, at a customer's dock, or on a rejection debit note.
An incoming inspection checklist (also called an IQC checklist or receiving inspection checklist) is the cheapest quality gate in your plant. In my 14 years running plants, every major supplier escape I dealt with traced back to a lot that was waved through goods inward. Here is the checklist I wish every stores and quality team pinned above the receiving bench — and how to run it without drowning in paperwork.
What incoming inspection covers
Incoming inspection (IQC — incoming quality control) is the verification of purchased material, parts, or subcontracted work before it is accepted into stock. ISO 9001:2015 clause 8.4.3 requires you to define the verification activities you perform on externally provided products, and clause 8.6 requires evidence of conformity before release. The checklist below is how you turn those clauses into a 20-minute routine at the receiving bench.
It is not 100% inspection. A good incoming inspection samples intelligently, checks the characteristics that actually fail, and creates a traceable record so a problem lot can be quarantined by GRN number in minutes.
The incoming inspection checklist
| # | Check | What to verify |
|---|---|---|
| 1 | Documents | Invoice, delivery challan, PO number match; test certificates (TC/MTC) attached; COC where required |
| 2 | Identity | Part number and revision on label matches PO and drawing revision; no mixed lots in one bin |
| 3 | Quantity | Physical count or weigh-count against challan; note shortages before signing |
| 4 | Packaging & handling damage | Rust, dents, thread damage, broken corners, wet cartons; photograph anything abnormal |
| 5 | Visual & workmanship | Burrs, tool marks, plating coverage, weld spatter, casting defects against the approved sample or drawing notes |
| 6 | Dimensional | Sample per AQL plan; measure the critical and major characteristics from the ballooned drawing |
| 7 | Material certificate | TC grade matches drawing callout (e.g., EN31, AISI 1045, Al 6061-T6); heat number traceable to the lot |
| 8 | Special processes | Plating thickness, hardness (HRC), heat-treatment reports where the drawing specifies them |
| 9 | Disposition & record | Accept / reject / deviation; tag the lot, log the inspection report against the GRN, move to correct location |
How much to inspect: AQL sampling in practice
Full inspection of every dimension on every piece is neither possible nor useful. Most plants sample using ISO 2859-1 (equivalent to the old MIL-STD-105E / IS 2500 Part 1) single sampling plans, general inspection level II:
| Lot size | Sample size (Level II) | AQL 1.0 — Accept / Reject |
|---|---|---|
| 281–500 | 50 | 1 / 2 |
| 501–1,200 | 80 | 2 / 3 |
| 1,201–3,200 | 125 | 3 / 4 |
| 3,201–10,000 | 200 | 5 / 6 |
A common working scheme: AQL 0.65 or 1.0 for critical characteristics, 1.5 for major, 4.0 for minor and visual defects. Tighten to Level III or 100% inspection for new suppliers and for any supplier coming off a rejection; relax to Level I after five consecutive clean lots. The exact numbers matter less than writing them down and applying them consistently — auditors look for the rule, not the value.
Dimensional checks need a ballooned drawing
This is where most incoming inspection quietly falls apart. The inspector gets a drawing with 60 dimensions and a verbal instruction to "check the important ones." Which ones got measured last time? Nobody knows, because the report says "dimensions OK."
The fix is the same one used for a first article inspection: balloon the drawing once, mark which balloon numbers are critical (C), major (M), and minor (m), and inspect against balloon numbers. Your incoming report then reads "balloons 3, 7, 12, 18 measured on 50 pcs — all within tolerance," which is traceable, repeatable, and audit-proof. If you have never set this up, the guide on converting a drawing into an inspection sheet walks through the whole process.
What records ISO 9001 actually expects
For each inspected lot, retain: the GRN or inward reference, part number and revision, supplier and lot/heat number, sample size and plan used, characteristics checked with actual readings (not just tick marks), instrument IDs used, the result and disposition, and the inspector's name and date. If you reject, the record should also show the NC report number and where the quarantined material physically went. The ISO 9001 inspection documentation guide covers retention periods and formats in detail.
Common incoming inspection mistakes
- Signing the challan before checking quantity and damage. Once signed, your commercial claim against the transporter or supplier is nearly dead.
- Checking against an old drawing revision. Always pull the revision from the PO, not from the inspector's folder of printouts.
- Recording "OK" instead of actual readings. Actuals let you spot a drifting supplier before parts go out of tolerance; ticks tell you nothing.
- No skip-lot logic. Inspecting a 10-year proven supplier at the same intensity as a new one wastes inspector hours that critical parts need.
- Accepted-with-deviation lots entering normal stock. Deviation lots need their own tag and traceability, or the concession silently becomes the new standard.
- Material certs filed unread. Match the grade and heat number to the drawing every time — a TC for the wrong grade is a recall waiting to happen.
How CadNexa speeds this up
The slow part of a proper IQC setup is building the ballooned drawing and characteristic list for every purchased part. CadNexa's PDF balloon tool does this in minutes: open the supplier drawing PDF, run Smart Detect or Box+Balloon OCR to pick up dimensions and tolerances automatically, mark criticality, and export the characteristic list as CSV for your incoming inspection register. The same ballooned drawing then serves FAI, PPAP, and incoming inspection — one source of truth per part, made once.
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Turn a PDF drawing into a numbered incoming inspection sheet in under 10 minutes.
Try the Balloon Tool — Free →FAQ: incoming inspection
What is the difference between incoming inspection and first article inspection?
First article inspection (FAI) is a one-time, full verification of every characteristic on the first parts from a new or changed process. Incoming inspection is the routine, sampled check applied to every subsequent lot. FAI proves the process can make the part; IQC confirms each delivery still does.
Which AQL should I use for incoming inspection?
A common baseline is AQL 1.0 for critical characteristics, 1.5 for major and 4.0 for minor/visual, at ISO 2859-1 general level II. Contracts or customer standards override this — automotive and medical customers often specify tighter plans or 100% checks for safety characteristics.
Can incoming inspection be skipped for trusted suppliers?
Yes — through a documented skip-lot or dock-to-stock program. Qualify the supplier with consecutive clean lots and audit evidence, define the reduced scheme (for example, one lot in five), and state the re-entry trigger: any rejection returns the supplier to normal inspection immediately.
What should an incoming inspection report format contain?
Part number and revision, supplier, GRN and lot/heat number, sample plan and size, ballooned characteristics checked with actual readings, instruments used, result, disposition, inspector and date. A CSV or spreadsheet register works; the key is actual values against numbered characteristics.
For more practical quality guides, visit the CadNexa learning center.