CNC Turning Service Parts

You are not limited to one alloy family, and every incoming lot is verified by XRF against its mill certificate before it reaches a machine, so the material you specify is the material you receive.

Material family	Grades	Notes for buyers
Aluminum	6061, 6063, 6082, 7075, 2014	Most common prototype and production choice; anodizes well
Stainless steel	303, 304, 316, 316L, 17-4PH	303 for free-machining, 316L for corrosion, 17-4PH for strength
Carbon / alloy steel	1018, 1045, 4140, 4340, 12L14	Carburizing or nitriding available for wear parts
Brass / copper	C360, H62, C110	For electrical and thermal conductivity
Titanium	TA2, TC4 (Grade 2 / 5)	Stress-relief above 500 °C is outsourced to a qualified partner
Plastics	ABS, POM (Delrin), nylon, PTFE, PEEK	For non-metal prototypes and insulators

What tolerances can the shop actually hold?

A tolerance on paper means nothing without the measurement to back it. Tolerances are tied to the process, and every critical dimension is checked on a CMM rather than taken on faith.

Process	Held tolerance	Typical use
CNC turning	±0.002 mm	Shafts, pins, bushings, round parts
CNC milling	±0.003 mm	Housings, brackets, prismatic parts
Precision grinding	±0.002 mm	Bearing seats, roundness-critical surfaces

We hold these to process capability, not a best-case 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. If a print calls out a dimension we cannot reliably hit, you hear about it during the DFM review — before cutting, not after.

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.

Which machining processes run in-house?

Having the process in-house means one accountable supplier and a shorter lead time, because most parts do not leave the building between operations.

Process	Capacity	Max workpiece
CNC turning	25+ lathes (incl. Swiss-type and mill-turn)	Ø720 × 1280 mm
3-axis milling	50+ centers	1300 × 700 × 600 mm
4-axis milling	20+ centers
5-axis milling	20+ centers
Grinding	7+ (surface / centerless / cylindrical)	±0.002 mm finishes

How does in-house inspection reduce the quality cost bucket?

The quality bucket is where most hidden cost lives, and in-house inspection is what keeps it small. The inspection bench is the same class of equipment a buyer would use to audit the shop — Hexagon GLOBAL S CMMs, a KEYENCE VK-X3000 laser microscope, a SURFCOM 1800D for surface finish, XRF for incoming material composition, and micro-Vickers hardness plus salt spray and tensile testers. The results are documented, not just pass/fail, so what ships is what was measured.

This matters to TCO because a defect caught at first article costs one part; the same defect caught at your incoming dock costs the batch and the schedule. In-house measurement moves detection to the cheapest point in the chain.

The documented result is the other half of the value. A pass/fail tag tells you nothing about where the part sits inside its tolerance band; a measured value, on an SPC chart over the run, tells you whether the process is centered and stable or skating along one edge. That is the difference between a batch you accept on faith and a batch you accept on evidence.

Which certifications back the quality system?

Certifications are the cheapest pre-audit you can run — they tell you a shop already operates a documented, third-party-surveilled system.

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

Honest scope note: IATF 16949 excludes product design under Clause 8.3. This is a build-to-print manufacturer — if a program needs design responsibility owned, say so up front and it will be scoped accordingly rather than over-promised.

What should you check before placing an order?

Whether you buy here or elsewhere, these are the checks that separate a real manufacturer from a markup — run them on any shop, including this one.

How does material grade affect the price and risk of a machined part?

The grade you specify, not just the material family, sets the cost and the risk. 6061-T6 and 7075-T6 are both aluminum, but 7075 is harder to cut and costs more; 303 and 316 are both stainless, but 303 is free-machining while 316 fights the tool. The grade you write on the drawing is the difference between a part that runs fast and one that runs slow.

Grade also decides how the part behaves in service. 316 resists corrosion that would pit 303; 7075 holds strength where 6061 would yield. The right grade is the one that meets the function at the lowest machining cost, and a shop that knows the grades can tell you which one that is before you quote.

How do tolerances and surface finish interact on a machined part?

Tolerance and surface finish are usually specified together, but they are bought separately. A part can be dimensionally tight yet rough — held to ±0.002 mm (turning) / ±0.003 mm (milling) but left at Ra 3.2 µm — or smooth but loose. Each costs its own money, and the combination is what drives the process: a tight tolerance plus a fine finish usually means a grinding pass, which is the most expensive step on the page.

your rule is to specify each only where function demands it. A bearing seat needs both; a clearance hole needs neither. Splitting the two — asking for the tolerance and the finish the part actually needs, separately — is the single cheapest change most drawings will accept.

Which parts are best suited to turning versus milling?

The shape decides the process, and the process decides the cost. Rotationally symmetric parts — shafts, pins, bushings, spacers — belong on a lathe, where a continuous cut makes them cheap in cycle time. Prismatic parts — housings, brackets, plates — belong on a mill, where the geometry is cut feature by feature. A part with both, such as a shaft with a wrench flat or a cross-hole, runs on a mill-turn center so it is done in one setup.

Choosing the right process is a cost decision made at the drawing stage. A part designed to be turned costs less than the same function designed to be milled, and a part designed for mill-turn costs less than the same part run through two machines. The DFM review flags this before you quote, so the process matches the shape instead of the shop's habits.

How does design-for-manufacturing lower the cost of your part?

Every design rule that removes an operation lowers the part's cost without lowering its function. Avoid deep blind holes; keep wall thicknesses uniform so the part does not deflect; let internal radii default to standard tooling; and tolerance only the features that control function. Each of these is a removal — of a pass, a check, or a secondary operation.

The savings compound because they hit every line item at once: less cycle time, fewer tools, less scrap, and fewer inspection holds. A shop that returns a DFM review with the quote is doing this work for you; a shop that quotes the drawing as-is is pricing every avoidable operation into your part.

What this shop actually runs

If you ask for capability evidence, you deserve a specific answer. This facility operates 100+ CNC machines across 6,800 m2 in Dongguan, China, staffed by 100+ people. The machines, listed 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). Set up 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). Set up 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). Set up 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). Set up for shafts, bushings, flanges up to ±0.002 mm.
• Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Set up 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.

Tolerance bands: ±0.003 mm milled, ±0.002 mm turned, ±0.002 mm ground or wire-cut. Capability indices: Ppk >= 1.67 at the initial study; Cpk >= 1.33 ongoing in production.

Certifications: ISO 9001:2015 (116024/A/0001/UK/En) · IATF 16949:2016 (131941/A/0001/SM/En, design clause 8.3 excluded) · ISO 14001:2015 (116024/B/0001/UK/En), held by Dongguan Zhuohang Ltd (USCC 91441900MA4UWT6X39, since 2005).

Service area: we supply 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, with worldwide delivery from China.

Contact: Felipe Iglesias, [email protected], +86 13126536955.

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