Quality control in metal stamping means verifying parts against the drawing at every stage (incoming material, first article, in-process, final, and outgoing inspection) and keeping a traceable record for every lot. When you evaluate a stamping supplier, owning a CMM isn't enough. What matters is whether the inspection gates are complete, whether measurement methods match your critical dimensions, and whether the supplier can hand you verifiable documentation with each shipment.
Key Takeaways
- HIROKI's stamping quality system covers seven elements: IQC, FAI, IPQC, FQC, OQC, lot traceability, and QC reporting.
- First articles are fully measured with a CMM, optical projector, and optical image sorting machine, and the FAI report ships with samples.
- Outgoing inspection follows AQL or your sampling plan, with 100% inspection available and a QC report for each lot.
- Tapping and assembly keep lot traceability records covering material, tool usage, and assembly personnel.
HIROKI CO., LTD., a Taiwan metal stamping manufacturer founded in 1950, runs a quality system that covers incoming material inspection, process control, and final product inspection. This article brings HIROKI's inspection capabilities, which are described across several service pages, together in one place: the purpose of each gate, how it's performed, and the equipment behind it.
- STEP 01IQCIncoming
- STEP 02FAIFirst article
- STEP 03IPQCIn-process
- STEP 04FQCFinal
- STEP 05OQCOutgoing
- STEP 06TraceabilityLot records
- STEP 07QC ReportShips with lot
What Are the Inspection Gates in a Stamping Quality System?
HIROKI's stamping quality system covers seven elements: IQC, FAI, IPQC, FQC, OQC, lot traceability, and QC reporting, which together address risk in material, tooling, process, finished parts, and shipment. Each gate catches a different kind of defect. Skip one, and problems move downstream, sometimes all the way to your receiving dock.
| Gate | Full Name | When | What It Verifies |
|---|---|---|---|
| IQC | Incoming Quality Control | Raw material and purchased parts arrive | Material grade, gauge, surface, quantity |
| FAI | First Article Inspection | T1 die tryout or first production piece | Full-dimension layout; die and process setup |
| IPQC | In-Process Quality Control | Scheduled checks during production | Dimensions and appearance stay in control |
| FQC | Final Quality Control | After stamping and secondary operations | Dimensions, cosmetics, threads, fit and function |
| OQC | Outgoing Quality Control | Before packing and shipment | AQL or customer-specified sampling |
| Lot traceability | — | Entire workflow | Material, tooling, and assembly records |
| QC report | Quality Control Report | Ships with the lot | Documented inspection results |
What Does Each Inspection Gate Check?
2.1IQC: Stop Material Problems at the Door
IQC (Incoming Quality Control) verifies raw material and purchased components on arrival, confirming grade, gauge, and surface condition before anything reaches the press. Dimensional stability in stamping depends heavily on consistent strip. A gauge variation or wrong grade changes springback and shortens die life. HIROKI's common materials include SPCC cold-rolled steel (comparable to ASTM A1008 CS), SPHC hot-rolled steel, SUS304 and SUS430 stainless (AISI 304 and 430), high-strength steel, S45C medium-carbon steel (comparable to AISI 1045), 5052 and 6061 aluminum, galvanized steel, copper, and phosphor bronze.
2.2FAI: Validate the Die With a Full Layout
FAI (First Article Inspection) is a full-dimension measurement of the first parts from a new die or production run, confirming tooling and process settings before volume production begins. In HIROKI's custom stamping solution, FAI is part of Stage 4, Sampling and Verification:
- Run the first die tryout (T1 sample) on the selected press.
- QA measures every dimension using a CMM, optical projector, and optical image sorting machine.
- Submit samples with the FAI report so you can run your own validation and fit testing.
- Fine-tune the die based on your feedback and inspection results until samples fully conform.
2.3IPQC: Keep the Process in Control
IPQC (In-Process Quality Control) means QC staff check parts at scheduled intervals during production to keep dimensions and appearance within control limits. Before launch, HIROKI establishes a standard operating procedure (SOP) that locks in production parameters. Its presses are equipped with stroke monitoring and load sensors, and together with periodic measurement and preventive die maintenance, this helps catch dimensional drift from die wear or feed misalignment early.
2.4FQC: Verify the Part After Secondary Operations
FQC (Final Quality Control) confirms dimensions, cosmetics, threads, and assembly function after stamping and all secondary operations are complete. Because deburring, grinding, tapping, finishing, and assembly all change the part, HIROKI matches the inspection method to each operation:
- Deburring: Visual and tactile checks, plus CCD optical inspection, optical projector, and CMM.
- Surface grinding: Calipers, micrometers, CMM, and surface roughness measurement.
- Tapping: Go/no-go thread gauges and the three-wire method.
- Riveting: Pull-out and torque testing for joint strength.
- Surface finishing: Adhesion testing, gloss and color measurement, and comparison to approved samples.
- Assembly: Calipers, depth gauges, concentricity checks, and torque meters, with mistake-proofing fixtures.
2.5OQC: The Last Line of Defense
OQC (Outgoing Quality Control) is the final inspection before packing, confirming that dimensions, appearance, and function meet your specification. HIROKI samples to AQL or to your specified sampling plan, and 100% inspection can be arranged for parts with special requirements. After release, parts are packed with rust-preventive and impact-resistant packaging suited to the product.
2.6Lot Traceability: Find the Root Cause Fast
Lot traceability links each lot's material, tooling, processing, and assembly records so a quality issue can be traced back to its source. HIROKI maintains lot traceability records in tapping that track material and tool usage, and uses barcode lot verification in assembly, with records traceable from material source through to assembly personnel.
2.7QC Reports: Inspection You Can Verify
A QC report documents the inspection results for a lot and ships with the parts as part of your receiving record. HIROKI can include a lot-level QC report with each shipment and provides FAI reports during new part development. If you need a specific report format or characteristics, include those requirements in your RFQ.
What Inspection Equipment Does HIROKI Use?
HIROKI's inspection capability centers on a CMM, optical projector, and optical image sorting machine, supplemented by operation-specific gauges.
| Equipment / Gauge | Primary Use | Gate |
|---|---|---|
| CMM (coordinate measuring machine) | Full-dimension and geometric measurement | FAI, FQC |
| Optical projector | Profile and dimension comparison | FAI, FQC |
| Optical image sorting machine | Vision-based dimensional and cosmetic sorting | FAI, FQC |
| CCD optical inspection | Burr and edge condition | FQC |
| Calipers, micrometers, depth gauges | General dimensional checks | IQC, IPQC, FQC |
| Surface roughness measurement | Ground surface condition | FQC |
| Go/no-go gauges, three-wire method | Thread verification | FQC |
| Pull-out and torque testing | Rivet and fastener strength | FQC |
| Gloss meter, color measurement | Finish appearance | FQC |
| Stroke monitoring and load sensors | Press process monitoring | IPQC |
What Should Buyers Ask When Auditing a Stamping Supplier's Quality?
When qualifying a stamping supplier, confirm five things: complete inspection gates, measurement methods matched to critical dimensions, a defined sampling basis, FAI and lot-level QC reports, and lot traceability.
- Inspection gates: Are incoming, first article, in-process, final, and outgoing inspection all covered?
- Measurement capability: What equipment measures your critical dimensions, CMM or optical projector?
- Sampling basis: AQL or customer-specified? Can critical parts be 100% inspected?
- Documentation: Will you receive an FAI report and a QC report with each lot?
- Traceability: If something goes wrong, can material, tooling, and process records be traced?
Frequently Asked Questions
Select a question to expand the answer
Q1What's the difference between IQC, IPQC, FQC, and OQC?
The difference is timing. IQC inspects material on arrival, IPQC checks parts during production, FQC inspects finished parts after stamping and secondary operations, and OQC is the final check before shipment. Together they cover material, process, finished-part, and shipping risk in sequence.
Q2When is a first article inspection required?
FAI is performed for a new die tryout, after a die modification, and on the first piece of a production run. HIROKI measures every dimension with a CMM, optical projector, and optical image sorting machine, and submits the FAI report with samples for your approval before volume production.
Q3Can HIROKI ship a QC report with every order?
Yes. HIROKI can include a lot-level QC report with each shipment, and provides FAI reports for new parts. If you require a specific report format, characteristics, or sample size, specify it in your RFQ.
Q4Is outgoing inspection sampling or 100%?
Outgoing inspection follows AQL or your specified sampling plan, and 100% inspection can be arranged for parts with special requirements. Share your critical dimensions and acceptance criteria up front so the inspection plan can be built around them.
Q5If a quality issue occurs, can the cause be traced?
Yes. HIROKI keeps lot traceability records in processes such as tapping and assembly, covering material, tool usage, and assembly personnel. That makes it possible to identify where an issue originated and correct the die or process accordingly.
Get Quality Verified From the First Part
If you're qualifying a new stamping supplier or need a partner that delivers FAI reports and lot-level QC documentation, send us your drawing, critical dimensions, and acceptance criteria. HIROKI builds inspection gates and measurement methods into stamping process planning, and integrates metal stamping with secondary processing services so quality is documented from the very first part.
Include in your RFQ:
- 2D/3D CAD files with critical dimensions called out
- Acceptance criteria and sampling requirements
- Whether you need an FAI report
- QC report format and characteristics
- Estimated volume and shipment lots