- Quality scales with volume via SPC and Cpk.
- Ppk ≥ 1.67 initial critical, ≥ 1.33 general, from production data.
- Hexagon CMM, KEYENCE, XRF, micro-Vickers, Fischer, salt-spray, tensile.
- Material XRF-checked against mill cert on every lot.
- ISO 9001 / IATF 16949 / ISO 14001, numbers verifiable.
Why does quality scale with volume?
A single good part proves the process can cut the shape. A thousand good parts prove the process is stable. At volume, quality is no longer about one measurement, it is about keeping the process inside the band across the run, which is why Cpk and SPC, not a one-off CMM report, are the tools that matter when the count climbs.
We are build-to-print, so your drawing sets the spec and our job is to hold it at part one and part ten thousand. The same measurement method applies at both ends; only the sampling plan changes.
Quality cost splits into three buckets, and only one is what buyers usually picture. Prevention cost is what you spend to stop defects before they happen — process planning, control plans, trained operators. Appraisal cost is what you spend to find defects — inspection, CMM measurement, material checks. Failure cost is what you pay when a defect escapes — scrap, rework, line stoppage, field returns. The three are not equal: prevention and appraisal are cheap and predictable; failure is expensive and compounds the further a defect travels. The supplier that invests in process control is pre-paying for quality so you do not have to pay for its absence.
Which certifications back the quality system?
The system is certified to ISO 9001:2015 (116024/A/0001/UK/En), IATF 16949:2016 (131941/A/0001/SM/En, manufacture of CNC metal machining parts, excluding product design under Clause 8.3), and ISO 14001:2015 (116024/B/0001/UK/En). All numbers are verifiable with the registrars. The IATF scope is stated honestly: we make to your print, we do not design it.
| Standard | Certificate number | Scope |
|---|---|---|
| ISO 9001:2015 | 116024/A/0001/UK/En | Machining of metal parts |
| IATF 16949:2016 | 131941/A/0001/SM/En | Manufacture of CNC metal machining parts (excludes product design, Clause 8.3) |
| ISO 14001:2015 | 116024/B/0001/UK/En | Environmental management related to machining of metal parts |
A certificate is a pre-audit you get for free: it tells you the shop already runs a documented system under third-party surveillance. The certificate number is the part you check — with the registrar, not against the supplier's own summary. And read the scope as carefully as the number, because a build-to-print scope is a different promise than a design-owning one.
How are dimensions verified before shipping?
Critical dimensions are measured on Hexagon CMMs; fine edges and small features under a KEYENCE laser microscope; hardness with a micro-Vickers; coating thickness with a Fischer gauge. At volume this runs against a control plan with defined sampling; critical features are measured per-part where the drawing demands it. Each result ties to the part and lot.
- Hexagon GLOBAL S CMMs for dimensional verification, plus vision measuring machines and a gear measuring center.
- KEYENCE VK-X3000 laser microscope and SURFCOM 1800D for surface finish and profile.
- XRF spectrometer for incoming material composition checks against the mill certificate.
- HVS-1000A micro-Vickers hardness tester, Fischer coating thickness gauge, salt spray and tensile testers.
The point of that bench is not to look impressive — it is to produce the reports that let you trust the parts without opening every box yourself. A CMM report with measured values against your drawing, an SPC chart with a computed Cpk, and a material certificate matched to an XRF check are the documents that turn a promise into a fact. A shop that measures to a micron but reports with a check mark cannot vouch for its own tolerance.
| Check | Instrument | What it catches |
|---|---|---|
| Critical dimensions | Hexagon CMM | Deviation from the drawing tolerance |
| Fine edges, small features | KEYENCE laser microscope | Burrs, edge quality, tiny geometry |
| Incoming alloy | XRF spectrometer | Substituted or mixed grade at the door |
| Hardness | Micro-Vickers | Heat-treatment and material hardness |
| Coating thickness | Fischer gauge | Plating and coating conformance |
How is process capability measured at volume?
We report Cpk: ≥ 1.67 on critical characteristics and ≥ 1.33 on general characteristics, calculated from production measurement data. At high volume Cpk is the cost lever, because stable capability keeps scrap low and low scrap is the largest driver of unit price once setup is amortized. Ask for the study from a job like yours and read the sample size.
Cpk is only as honest as the data behind it. A number copied from a handbook means nothing; a study from a job like yours, with a named characteristic and a stated sample size, means something. Ask for the characteristic, the sample size, and the control chart. If the supplier will not show them, treat the number as unverified.
What is the difference between Cp and Cpk?
Both numbers describe how a process fits inside its tolerance band, but only one tells you whether the process is centered. Cp measures the width of the process spread against the width of the tolerance — it assumes the process sits in the middle. Cpk corrects for position: it measures the distance from the process mean to the nearer limit, so a process that drifts off-center shows a falling Cpk even when its spread has not changed.
The difference is why Cpk is the number you should ask for. A process can show a healthy Cp while quietly drifting toward one limit, producing parts that are in spec today but one shift away from out of spec tomorrow. Cpk catches that drift, because it collapses the moment the mean moves. A supplier that reports Cpk rather than Cp is reporting a number that accounts for both spread and centering, which is the number that actually predicts scrap.
How is incoming material verified?
Every incoming lot is XRF-checked against the mill certificate before cutting, catching a substituted grade that compounds across a whole run. The mill certificate and XRF record ship with the part. At volume this step protects the entire batch, not just a sample.
The check matters because alloy is not always visible. Two stainless grades can look identical and perform very differently, and a supplier that trusts the label rather than the measurement is gambling with your part's function. Verifying material by composition against the certificate costs minutes and prevents the cost of an entire batch built from the wrong stock, which is why it runs on every lot, not just the regulated ones. The mill certificate and XRF record then ship with the part, so the verification you paid for is documented in your hand rather than promised over the phone.
How are parts traced back to the raw material?
Each lot carries its material certificate, XRF check, inspection result, and certificate of conformity, linked by a lot or work order number. For automotive-linked work under IATF 16949 the traceability is built in. Outsourced steps are named with partner and certificate, so the chain has no undocumented gap even as volume grows.
Traceability is what turns a spot check into a recall boundary. If one lot is suspect, you want to isolate exactly that lot, not quarantine everything you have shipped. The lot number is the handle that lets you do that in hours instead of weeks.
For regulated buyers that traceability is a requirement; for everyone else it is cheap insurance against the costliest kind of failure — the one where you cannot prove which parts are bad and have to treat them all as suspect. The chain begins with an XRF check of incoming material against its mill certificate, and it runs on every job, not just the ones that demand it.
What documentation ships with a quality part?
A shipment carries the material mill certificate, the XRF verification record, a CMM or inspection report on critical dimensions, an SPC summary where relevant, and a certificate of conformity. Tell us the package you need in the PO and we supply it as standard, at any volume.
- The first-article inspection report: measured values against every critical dimension, not a check mark.
- The material certificate matched to an XRF check: the alloy you specified, verified by composition.
- The SPC control chart: the chart behind the Cpk, showing measured values over the run.
- The CMM report: dimensional verification of the shipped lot, tied back to the drawing.
Those four documents cost the supplier minutes to produce and a buyer almost nothing to ask for, yet they are the difference between a supplier whose quality you can verify and one whose quality you must take on faith. Documentation is also the record that makes traceability work — when a problem surfaces later, the paper trail tells you which lot, which machine, and which operator produced it.
How do you challenge a quality claim?
Certificates and Cpk numbers can be real or copied. The way to separate them is to ask for the record behind the claim, not the logo on a website. A supplier that can hand you the record — the Cpk study, the CMM report, the control chart, the mill certificate — is one whose quality you can verify; a supplier that deflects to a summary page is one whose quality you would have to take on faith.
- Ask for the certificate number and check it with the registrar, not the supplier's summary.
- Ask for a Cpk study from a job like yours and read the sample size it is built on.
- Ask which instrument measured the critical dimension, and for the actual report.
- Ask whether the XRF check runs on every incoming lot or on a sample.
- Ask for the mill certificate and lot traceability for the parts you will receive.
Read the tolerance band before you read the index. Cpk is a ratio of the tolerance band to the process spread, not an absolute measure of accuracy. The figure above was recorded on a length characteristic with a 0.4 mm band (76.1–76.5 mm) — wide by design. Hold the same process spread against a ±0.005 mm feature and it fails outright. Ask for the band, the subgroup count and the sampling window on every capability number a supplier quotes.
What this shop actually runs
Ask for capability evidence and the answer should be specific. The facility behind this guide runs 100+ CNC machines on a 6,800 m2 floor in Dongguan, China, with 100+ staff. The machine list, by category:
- 5-axis machining centres (10+) - Mazak VARIAXIS I-600 (510/910/510 mm travel, 12,000 rpm, 22 kW, 71.6 N·m, 30-tool BT40) and Mazak INTEGREX I-250H S (B-axis 0.0001°, 24 kW, 124 N·m, 38-tool HSK-A63). Typical work: compound-angle parts, single-setup multi-face prismatic work, and aerospace fittings where datum transfer loss is unacceptable.
- 3-axis / 4-axis machining centres (50+) - Brother SPEEDIO S500Z2N / S700Z2N (10,000 rpm, 14/21-tool ATC, 0.7 s tool-to-tool, Z-axis 2.2 G) and Mazak VCE-430A L / VCE-570C L (10,000 rpm, 118 N·m, 24-tool ATC). Typical work: prismatic parts, plates, brackets, housings.
- Swiss-type turning centres (10+) - Citizen Cincom A20-3F7 (Φ20 mm, 10,000 rpm), TSUGAMI B0206-III / B0205-III (Φ20 mm, 0.1 µm), STAR SR-32JII / SR-32J Type N (Φ32 mm, 8,000 rpm). Typical work: long, slender rotational parts at ±0.002 mm.
- CNC turning centres (20+) - HEADMAN T70M/1250 (720 mm swing, 117 mm bore, 3,000 rpm, BMT75 12-station turret). Typical work: shafts, bushings, flanges up to ±0.002 mm.
- Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Typical work: hardened tool steel, internal splines, sharp internal corners that milling cannot reach.
- Inspection: Hexagon CMM + 20+ gauges - Hexagon CMM for coordinate measurement, plus vision system, profilometer, hardness tester, coating thickness gauge, XRF for material verification. The 10:1 rule (gauge 10x more accurate than the band) is applied to every feature.
- Machine highlights - VARIAXIS I-600: one-setup multi-face 5-axis + MAZA-CHECK auto-calibration; INTEGREX I-250H S: DONE-IN-ONE mill-turn, B-axis 0.0001° + Ai thermal shield; SPEEDIO S500Z2N / S700Z2N: Z-axis 2.2 G + 0.7 s ATC; Swiss-type: guide-bush switchable + 0.1 µm resolution.
Tolerances held: milling ±0.003 mm, turning ±0.002 mm, grinding and wire EDM ±0.002 mm. Capability: Ppk >= 1.67 initial and Cpk >= 1.33 in production on key characteristics.
Certifications: ISO 9001:2015 (116024/A/0001/UK/En), IATF 16949:2016 (131941/A/0001/SM/En, clause 8.3 design excluded, disclosed openly) and ISO 14001:2015 (116024/B/0001/UK/En), issued to Dongguan Zhuohang Ltd, USCC 91441900MA4UWT6X39, established 2005.
Service area: Austria, Belgium, the Czech Republic, Denmark, France, Germany, Greece, Hungary, Ireland, Italy, the Netherlands, Spain, Sweden and the United Kingdom in Europe; Brazil, Canada, Mexico and the United States in the Americas; China, Israel, Japan, Singapore and Sri Lanka in Asia; Australia and New Zealand in Oceania; and South Africa in Africa — built in China, shipped worldwide.
Contact: Felipe Iglesias, [email protected], +86 13126536955.
Send your drawing for a quote.
Email [email protected] or call +86 13126536955 for a review and quote.
Frequently Asked Questions
What certifications do you hold?
ISO 9001:2015 (No. 116024/A/0001/UK/En), IATF 16949:2016 (No. 131941/A/0001/SM/En), and ISO 14001:2015 (No. 116024/B/0001/UK/En). The IATF 16949 scope excludes product design under Clause 8.3, so we are a build-to-print manufacturer.
How do you verify dimensions?
Critical dimensions are checked on Hexagon GLOBAL S CMMs, supported by vision measuring machines and a gear measuring center. We hold process capability to Ppk ≥ 1.67 at the initial study on key characteristics.
How do you verify incoming material?
Every incoming lot is checked by XRF spectrometer against its mill certificate before it reaches a machine. This catches substituted or mixed alloys at the door.
Do you provide inspection reports?
Yes. CMM dimensional reports, SPC charts, and material certificates ship with your parts. For automotive and regulated work we can also run PPAP and FAI packages on request.
What is your process capability standard?
In short, We target Ppk ≥ 1.67 at the initial study on key characteristics and ≥ 1.33 on general characteristics. On a representative length characteristic our SPC shows Cpk = 1.851 (one characteristic on one part, not a blanket capability claim), measured over 25 subgroups.
What is the difference between Cp and Cpk?
In short, Cp measures the spread of the process against the tolerance width; Cpk also accounts for whether the process is centered. A process that drifts off-center keeps a healthy Cp but shows a falling Cpk, which is why Cpk is the number that predicts scrap.
Why is a defect cheapest to catch at the machine?
In short, A defect caught at the machine costs the scrap value of the stock; the same defect caught at your assembly line costs a stoppage, and at your customer it costs a return and a reputation. Keeping defects at the machine through SPC and inspection is effectively a discount on your downstream rework bill.
How do I request quality documents?
Email [email protected] and specify which documents you need. We provide documentation that matches the part, and we do not send documents we cannot back with a real job.
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Standards referenced on this page
- IATF 16949:2016 — Automotive quality management system standard
- ASTM A582/A582M-12 — Standard Specification for Free-Machining Stainless Steel Bars
- ISO 14001 — Environmental management systems — Requirements with guidance for use