CNC Milling Services Parts

True position and profile are relationships measured against datums on a CMM. Our Hexagon GLOBAL S CMMs measure the actual feature, so a hole that is on size but off position is caught before it ships. The CMM builds the datum reference frame from the drawing, then measures each controlled feature against it, which is the only way to verify a relationship, as opposed to a list of sizes.

How are parts verified before they ship?

The inspection bench is the same class of equipment a buyer would use to audit the factory, and the results are documented rather than assumed. Each instrument verifies a different part of the drawing.

• Hexagon GLOBAL S CMMs (2) 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 (iCHEQ) 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.
• SPC: control charts on key characteristics, with Ppk ≥ 1.67 at the initial study on critical characteristics and Cpk ≥ 1.33 in production on general characteristics.

Which secondary operations affect tolerances?

Surface finishing and heat treatment can shift dimensions, which is why they are planned in the same review as the machining. Anodizing builds thickness; heat treatment can warp. We account for both before cutting, so the finished part — not the machined blank — meets the callout. The dimensional effect of every finish is owned by the process plan, not discovered at final inspection.

What should you check before ordering parts?

How does first-article inspection close the loop?

A first-article inspection measures the first completed part against every callout on the print before the batch runs. It catches fixture error, tool deflection, and setup drift while there is still one part to fix, not a full lot to scrap. For a build-to-print job, the FAI is where the datum scheme is proven on a real part instead of argued on paper.

Pair the FAI with lot traceability. A measured dimension is only useful when it can be tied back to the material lot, the machine, and the operator. Months later, the report and the lot record together answer the question.

Document	What it proves	What it does not prove
FAI report	The setup holds the print on the first part	Every part in the lot
Final inspection report	The lot meets the checked dimensions	Dimensions not on the report
Material certificate + XRF	The grade you specified is the grade received	Anything about geometry

• Ask for the FAI report, not just the final inspection report. The FAI proves the setup; the final report proves the lot.
• Ask how dimensions map to datums on the report. A list of sizes without datum references is not GD&T verification.
• Ask whether material lot and machine are recorded per dimension. That is the difference between traceability and a printout.
• Ask what happens when a dimension drifts mid-lot. The answer should be a corrective action, not a re-run.

What do the common material grades give you in a machined part?

The grade is not just a name; it is a set of properties that decide how the part behaves in service and how it machines. Choosing the right grade is a design decision that the machining process has to live with, and the table below states the trade-offs that matter to a buyer.

Grade	What it gives you	Machining note
6061-T6	Good strength-to-weight, corrosion resistance, weldable	Free-cutting; the precision default
7075-T6	High strength, aircraft-grade	Harder; watch for stress relief after heavy cuts
304 stainless	General corrosion resistance, food-safe	Work-hardens; slower feeds
316 stainless	Marine-grade corrosion resistance	Work-hardens more than 304; slower still
4140 alloy steel	High strength after heat treatment	Machines well annealed; plan heat treatment

Which DFM rules keep a part machinable?

Design for manufacturability is the geometry discipline that keeps a part cheap and reliable to machine, and it matters most when tolerances are tight. A tight tolerance on an easy geometry is routine; the same tolerance on a hostile geometry is a scrap generator.

• Respect minimum wall thickness. A thin wall flexes under the tool, so a tight callout on a thin section is a fight against deflection.
• Keep hole depth reasonable. A deep, small hole wanders as the drill deflects; a tight position on a deep hole is optimistic.
• Leave internal corner radii. A sharp internal corner cannot be cut with a rotating tool; add the radius the tool needs.
• Give the datum a real surface. A datum that is a tiny edge or a curved face is hard to fixture and hard to measure.

How does the MOQ of 1 piece change what you can validate?

An MOQ of 1 piece means you can buy a single prototype to prove the design before committing volume. You validate the geometry, the tolerance, and the finish on one part, read the first-article report, and only then release the batch. That is the cheapest way to buy confidence — the cost of one part against the cost of a full lot that does not fit.

The 1-piece MOQ also lets you iterate. A design change after a single part is a line on a drawing; the same change after a thousand parts is a scrap bin. Prototype first, measure, correct, and then scale — the MOQ makes that sequence affordable instead of theoretical.

How is a part traced back to the raw material?

Traceability is the link that makes a measured dimension useful later. The MES/ERP system records raw material source and usage, process parameters, machine data, production batch, machining time, operator, and inspection results for every lot. If a non-conformance surfaces, the record points to the exact lot, machine, and operator, and the affected parts can be contained instead of the whole order replaced.

Incoming material is checked by XRF against the mill certificate, so the chain begins with a verified alloy. That discipline runs on every job, not just automotive ones, because a mislabeled alloy is the same cost to you regardless of the industry.

How do you keep a repeat order at the same tolerance as the first?

The first order pays for the learning: the setup, the tooling, the program that turns your drawing into chips. A repeat order should reproduce the first part exactly, because that learning is already banked. The difference is whether the shop keeps your fixture, your program, and your inspection plan on file, or whether every reorder is a fresh start.

A shop that keeps the fixture and the program reproduces the part without re-learning it, which holds the tolerance stable and the lead time short. A shop that loses that continuity charges you for the learning again, either in the price or in a slower ramp-up and the scrap that comes with it. When you compare suppliers, ask what happens on the second order: the answer is a forward price on your future batches, and it sits on the same ledger as the cost of switching.

That continuity is why a single accountable floor matters to repeat orders. If the same drawing has to be re-interpreted by a new shop, a new programmer, and a new operator, the variation shows up as first-article scrap and rework on your bill. A stable process on one floor turns a repeat order into a known quantity, which is the cheapest kind of order there is.

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). Built for 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). Built for 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). Built for 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). Built for shafts, bushings, flanges up to ±0.002 mm.
• Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Built for 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.

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