Quality control and inspection, documented
A ±0.005 mm claim is worth nothing without measured values behind it. This page sets out the checkpoints every order passes, the instruments used to pass them, and the paperwork that arrives with the parts.
Four checkpoints, every order
Inspection is not a final gate that rejects work. It is four points where a problem can still be fixed cheaply.
Incoming material
Bar and plate arrive with the supplier’s mill certificate. Grade, heat number and condition are checked against it before the material is released to a job. Wrong alloy is the most expensive mistake a machine shop can make and the cheapest to prevent.
First article inspection
The first part off the fixture is measured against a ballooned drawing — every dimension numbered, every GD&T callout evaluated on the CMM. Production does not continue until the FAI is signed, and a copy goes to you.
In-process patrol
Operators check the features their set-up influences, and a patrol inspector samples critical dimensions between operations. Where a dimension drifts, the offset is corrected at the machine instead of being sorted out at the end.
Final inspection and release
Finished lots are sampled to AQL on the dimensions that matter, checked visually for burrs, tool marks and finish defects, then packed and released with the document pack.
What ships with your parts
Anything on this list can be supplied as a PDF in the same email as the packing list, so your quality team does not have to ask twice.
| Document | When it is issued | What it proves |
|---|---|---|
| Mill certificate | With every lot | Alloy, heat number and condition traceable to the material supplier |
| First article inspection report | On request, or before batch approval | Every dimension on a ballooned drawing measured and recorded |
| CMM dimensional report | On request; sampling on production lots | Actual measured values with GD&T evaluation |
| Plating, anodizing or heat-treatment certificate | When those processes are used | Process specification and thickness and condition from the finishing partner |
| Certificate of conformity | With every shipment | The lot meets the drawing revision stated on your order |
| Packing list and commercial invoice | With every shipment | Quantities, weights and HS codes for customs clearance |
Tolerance capability in production
Standard figures apply to ordinary work; precision figures are the ones we hold on critical features and verify with CMM data.
| Parameter | Standard | Precision |
|---|---|---|
| Linear tolerance | ±0.02 mm | ±0.005 mm |
| Angular tolerance | ±0.5° | ±0.1° |
| Surface roughness | Ra 1.6 µm | Ra 0.4 µm |
| Concentricity | 0.02 mm | 0.01 mm |
| Perpendicularity | 0.02 mm | 0.005 mm |
When a part is out of specification
It happens in every machine shop; what differs is who finds it. Nonconforming parts are quarantined and identified before they can be mixed back into a lot, you are told the same day, and we come back with a root cause and a corrective action rather than an apology. Depending on the deviation we rework, replace or credit — the decision is documented on a nonconformance report so both sides know what was agreed.
The bias is deliberately to over-inspect at first article and report a marginal dimension before shipment, even when that costs a day. A dimensional problem found on our bench is a day; the same problem found on your assembly line is a week.
Third-party inspection and 100% checks
On precision and key parts the default is 100% inspection rather than sampling; on standard parts we sample to AQL, and a full check is available on request. If you want an independent set of eyes, we accept inspection by SGS, BV, TÜV or any third party you nominate, and we will hold the shipment until the report is issued. Inspection reports can be issued on your own template if your quality system requires a fixed format.
Where a defect reaches you despite all of that, the response is a free rework or replacement, an 8D report covering containment, root cause and corrective action, and we carry the freight and duty on the return. That commitment is in writing on the order acknowledgement, not just in a sales conversation.
Packing that survives the trip
Parts are degreased, dried and packed to the protection level you specify: anti-corrosion wrap for steel, individual bags for cosmetic surfaces, foam or cavity trays for tight-tolerance components, and moisture-barrier bags with desiccant for sea freight. Cartons carry part number, revision, quantity, lot and PO reference. Pallets are heat-treated to ISPM 15 and shrink-wrapped, and we photograph the packed pallet before it leaves.
Audits, questionnaires and factory visits
If your quality or purchasing team needs a supplier questionnaire completed, a video walkthrough of the shop, or a live visit during a China trip, ask. We sign an NDA before a visit, restrict photography to your own parts, and will walk you through the inspection records for jobs comparable to yours. Supplier audits against your own checklist are welcome with a week’s notice.