Metal Parts Manufacturer Services

How does the service keep every lot traceable?

MES/ERP records material source and usage, process parameters, machine data, batch, machining time, operator, and inspection results on every lot. The chain runs through the whole service, from incoming material to shipped part, so a non-conformance is isolated, not investigated blind.

Which machining services run in-house?

Keeping the core processes under one roof keeps the chain unbroken. Milling, turning, mill-turn, and grinding all run in-house.

Process	Capacity	Max workpiece
3-axis milling	50+ centers	1300 × 700 × 600 mm (milling)
4-axis milling	20+ centers
5-axis milling	20+ centers
CNC turning	25+ lathes	Ø720 × 1280 mm
Mill-turn	Multi-task centers	Single-setup complex geometry
Grinding	7+ machines	±0.002 mm finishes

The right process follows the stock and the features, not the marketing. Pick by geometry:

Part geometry	Process	Why
Revolved (shafts, bushings)	CNC turning	Fastest metal removal on round stock
Prismatic (housings, plates)	3-axis milling	Flat faces and pockets in one setup
Multi-side, fewer setups	4-/5-axis milling	One clamping, fewer datum errors
Complex round-plus-mill	Mill-turn	Finished in one setup, no re-clamping
Tight surface or diameter	Grinding	±0.002 mm and controlled finish

The process choice is a traceability decision as much as a cost one. Every time a part moves between machines, the chain gains a hand-off, and every hand-off is a place where a record can go missing. A mill-turn center that finishes a part in one setup shortens the chain and removes a clamping error in the same stroke.

How is material verified before it enters the chain?

Incoming bar is XRF-checked against its mill certificate so a mixed or mislabeled lot is caught at the door, and a material certificate with a heat number follows the batch through production. The chain starts with the material, because a wrong alloy defeats every step downstream.

The gate is cheap insurance. A mixed lot caught at incoming is a supplier conversation; the same lot caught after machining is scrap plus lost machine time. The cost of the XRF check is a rounding error against the cost of machining the wrong alloy.

How does the inspection bench close the chain?

Two Hexagon GLOBAL S CMMs verify critical dimensions, supported by a KEYENCE VK-X3000 laser microscope, a SURFCOM 1800D for surface finish, and an XRF spectrometer for material. CMM reports and SPC charts ship with the parts, so the chain ends in proof, not a pass/fail sticker.

Which secondary operations stay in the chain?

Surface finishing and heat treatment leave the building for qualified partners, but they do not leave the chain — each hand-off is recorded, extending traceability through the finish to the shipped part.

• Surface finishing: standard and hard anodizing, plating, powder coating, painting, brushing, polishing.
• Heat treatment: vacuum, bright, carburizing, nitriding, stress-relief aging. In-house ovens reach 500 °C; titanium stress relief above that goes to a qualified partner.

What tolerance does the chain prove?

Milling and turning hold ±0.003 mm (milling) / ±0.002 mm (turning) and grinding holds ±0.002 mm. On a representative length characteristic (76.1–76.5 mm), our SPC shows Cpk 1.851 (one characteristic on one part, not a blanket capability claim) against an initial-study target of Ppk ≥ 1.67 — a measured result that closes the chain.

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 red flags signal a traceability gap?

What should you ask a machining service before you quote?

• Which processes run in-house and which go out? The answer tells you where the record can break.
• How is material verified? "XRF-checked against the mill certificate" is a specific, testable answer; "we trust our supplier" is not.
• Does the service ship the inspection record with the parts? If not, the traceability stops at the loading dock.
• What is the minimum order quantity? One piece means you can prototype and validate before committing to volume.

How do you pick between milling, turning, and mill-turn?

The process follows the geometry, not the marketing. A revolved part — a shaft, a pin, a bushing — goes on a lathe, because turning removes round stock faster than any mill. A prismatic part — a housing, a plate, a bracket — goes on a mill, because flat faces and pockets are a mill's native geometry. The decision is made in the first five minutes of the DFM review, and it is a traceability decision as much as a cost one.

Every time a part moves between machines, the chain gains a hand-off, and every hand-off is a place where a record can go missing. A part that stays on one machine has one record; a part that visits three machines has three, plus the datum errors that come with re-clamping. That is why mill-turn exists: a round part that also needs milling is finished in one setup, so the chain has one link instead of four. The service picks the process that minimizes hand-offs, because the shortest chain is the cheapest to record and the easiest to trust.

For multi-sided prismatic parts, 4- and 5-axis milling play the same role. Instead of flipping a part through three setups, the machine indexes it in one clamping, so the datum stays fixed and the record stays single. The process choice is a cost decision, a quality decision, and a traceability decision all at once, and they usually point in the same direction.

How does machinability set the machining cost before you negotiate?

Machinability is a published property of a material, and it prices a part more reliably than the raw stock does. The easier a grade cuts, the faster the spindle turns, the longer the tool lasts, and the fewer setups a batch needs. That saving shows up in the machining cost, not the billet price, and it compounds across a production run.

Material family	Machining behavior	Effect on the machining cost
Free-machining brass (C360)	Chips break cleanly; tight threads run fast	Lowest machining cost of the common metals
Aluminum (6061 / 7075)	Fast feeds, good heat dissipation	Low cost; the default for prototypes and housings
Low-carbon / leaded steel	Predictable chip, moderate tool wear	Mid-range; workhorse for shafts and structure
Stainless (303 / 304 / 316)	Work-hardens as it cuts; slower feeds	Higher cost; free-machining 303 helps
Titanium (Grade 2 / 5)	Retains heat at the edge; frequent tool changes	Slowest to cut; priced for its function

The lesson is the same as everywhere else in the chain: pick the grade that earns its keep. A drawing that demands 316 where 304 would function is paying for corrosion resistance the part never uses, in machine time as well as in stock. The DFM review should name machinability as a stated factor, so the cost you are quoted is the cost the material actually drives.

What DFM rules shorten the service's chain?

Design-for-manufacturing is where the service shortens the chain before it starts. The same features that make a part hard to machine — deep pockets, sharp internal corners, thin walls — also make it hard to record, because they add setups, add hand-offs, and add dimensions that are difficult to verify. A DFM review that tightens the feature list tightens the chain.

• Internal corners need a radius. A cutter is round, so a sharp corner forces a second operation.
• Hole depth stays under about 4 diameters. Deeper holes drift and break tools.
• Wall thickness stays above roughly 0.8 mm. Thinner walls deflect under the cutter.
• Tolerances go only where they earn their keep. Every tight callout adds an inspection step.

How do surface finishes stay inside the service's chain?

An anodized part or a heat-treated part leaves the building for a qualified partner, but it does not leave the record. The lot number travels with the parts, the partner's certificate is filed against it, and the finish is checked when the parts return. The chain extends through the finish to the shipped part, because the finish is a step in the process, not an afterthought.

The honest disclosure matters more than the process itself. A service that says "we handle finishing" without naming the partner is hiding a hand-off; a service that names the partner and keeps the hand-off in writing is extending the chain across a company boundary. When you quote, ask where anodizing and heat treatment happen — the answer tells you where the chain could break, and an honest shop tells you plainly.

How does the service hold tight tolerances without over-charging?

The service ties tolerance to the process that produces it, so you do not pay for a grinding step your part does not need. Milling and turning hold ±0.003 mm (milling) / ±0.002 mm (turning); grinding holds ±0.002 mm. The DFM review is where the drawing's tolerances are matched to the processes, so a relaxed band stays on the cheaper process and a tight band is quoted with the inspection it actually requires.

The tolerance ladder is a cost ladder, and calling a tolerance you do not need is the fastest way to raise the price. A tight band on a bracket that could hold a relaxed one buys inspection time, not function. The service's job is to tell you which band the part needs, and the chain's job is to prove the band you chose was held.

The proof is the SPC chart, not the claim. On a representative length characteristic (76.1–76.5 mm), the SPC shows Cpk 1.851 (one characteristic on one part, not a blanket capability claim) against an initial-study target of Ppk ≥ 1.67, with general characteristics held to Cpk ≥ 1.33. That is a measured result that closes the chain, and it is the number you should ask to see before trusting a tolerance claim.

The same discipline runs through every process in the service. Milling and turning record their parameters at the point of machining, grinding records its passes and its profile checks, and the inspection bench records the measured value against the limit. No process gets a pass/fail shortcut, because a shortcut anywhere is a gap in the chain.

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

Frequently Asked Questions

Standards referenced on this page

• ASTM A276/A276M-17 — Standard Specification for Stainless Steel Bars and Shapes
• ASTM A582/A582M-12 — Standard Specification for Free-Machining Stainless Steel Bars
• ISO 9001 — Quality management systems — Requirements