China CNC Processing Services for Custom Metal and Plastic Parts

GreatLight was founded in 2011 and now runs three wholly-owned plants covering 7,600 m², with 150 technicians. The machine list is 127 high-precision CNC machines. That includes 16 simultaneous 5-axis machining centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers. The mix matters more than the total. A five-axis center removes a part from three or four separate setups, which is usually where position errors come from on angled holes and contoured faces.

Maximum processing size is 4,000 mm. Large travels are 4,000 × 400 × 150 mm, medium travels are 750 × 1,150 × 550 mm and 600 × 600 × 600 mm, and compact travels are 500 × 500 × 450 mm and 500 × 310 × 200 mm. Mill-turn work can use a Ø400 mm rotary table. If your part sits inside one of those envelopes and needs four or more faces machined, it is a candidate for a single-setup quote.

Not every part belongs on a five-axis machine. Simple prismatic plates with two drilled faces cut faster and cheaper on a three-axis mill, and we will quote them that way. Long, thin parts that need support along their length often run better on a mill-turn center, because the bar stays clamped while turning and milling happen in the same program. If your drawing calls for a 0.4 mm wall on a 300 mm aluminium plate, we will say so during DFM review rather than after the first cut.

• 1
  5-axis16 simultaneous centers, best for contoured or multi-face parts
• 2
  Mill-turn16 centers with a Ø400 mm rotary table for shaft-type work
• 3
  Size limit4,000 mm maximum processing size on the largest travel

Standard tolerance is ±0.005 mm, which is ±0.0002 in. That figure is achievable, not automatic. It depends on the feature. A bored bore in 6061-T6 held in a fixture can hold that band all day. A 3 mm deep slot in a 40 mm long aluminium arm, machined before stress relief, will move after clamping is released. We flag those features during DFM and suggest either a looser band or an added stress-relief step.

Surface finish is quoted three ways: Ra 0.2–0.8 μm for fine finishes, Ra 0.8–1.6 μm for high cosmetic surfaces, and Ra 1.6–3.2 μm as-machined. A fine finish is a separate operation with extra time, so specify it only where a seal, bearing or optical surface needs it. The rest of the part can stay as-machined.

The cost drivers are usually setup count, feature count and finish callout, in that order. A part that fits one five-axis setup with 30 features is often cheaper than a simpler part that needs three fixtures and two hand operations. Send STEP plus a 2D drawing with datums and critical dimensions, and the free DFM analysis in the quote will list anything we would change.

Every shipment gets 100% inspection before it leaves the plant. That means a raw material check on arrival, in-process monitoring while parts are running, and a final inspection on finished geometry. Inspection reports are available on request, including first-article reports and dimensional layouts for critical features. We do not ship a production lot on sampling alone.

The quality system holds ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. Those four cover different readers. IATF matters to automotive and EV programs because it brings the PPAP-style documentation and change control that tier-one suppliers expect. ISO 13485 applies to medical work and covers process validation and device history records. ISO 27001 is about your data, which is often the part procurement worries about most when a supplier is overseas.

The qualification rate across production runs is 99.99%. That number comes from inspection data, not from a marketing survey. Historical late-delivery probability is below 2%. Neither figure is a promise about your specific order. They describe what the shop has done, and they are the reason we can quote a 3–5 day ship date on many repeat jobs.

Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours of a released order, and parts ship in 3–5 days on jobs that fit our standard routing. There is no minimum order quantity. We run from one prototype to 10,000+ part runs, so a single bracket for a test rig and a production batch go through the same quoting path.

Uploads are secure and confidential. An NDA is available on request if your program requires one before drawings are shared. Sending STEP, PDF and a tolerance drawing together shortens the loop, because the DFM notes and the price come back in one pass instead of three.

The useful question is not whether a supplier is in China. It is which machines your part will run on, who inspects it, and what happens when a dimension is out. Ask for the machine list, the inspection plan and the material certificates. We answer all three in writing before the first chip is cut.