Advanced CNC Processing Company: Precision Parts

A precision part usually fails for one of three reasons: too many setups, a fixture that lets the part move, or a tool that cannot reach a feature without a second operation. An advanced CNC processing company manages those three risks before the first chip is cut. At GreatLight we run 127 high-precision CNC machines across three wholly-owned plants, in 7,600 m² of floor space, with 150 technicians. The mix matters more than the total: 16 simultaneous 5-axis machining centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers.

Five-axis work is not automatically better. If a part has features on four faces and a positional tolerance between them, one 5-axis setup removes the stack-up error you get from re-clamping. If the part is a simple plate with holes on one face, a three-axis machine is faster and cheaper, and we will say so. The rotary table on our 5-axis centers is Ø400 mm, which sets a practical limit on part size for that machine class.

Size drives the choice too. Our largest travel is 4,000 × 400 × 150 mm. Medium platforms run 750 × 1,150 × 550 mm and 600 × 600 × 600 mm. Compact platforms cover 500 × 500 × 450 mm and 500 × 310 × 200 mm. Maximum processing size is 4,000 mm, so parts beyond that need to be split or made another way.

Mill-turn centers handle parts that would otherwise need two machines and two fixtures. Shafts, bushings and housings with turned diameters plus milled flats or cross-holes are the usual fit. When a part needs both, keeping it in one spindle avoids re-datuming the turned bore against the milled features.

• 1
  Fewer setupsOne 5-axis setup removes re-clamping error between faces.
• 2
  Right machine classSimple prismatic parts belong on 3-axis, not a 5-axis center.
• 3
  Size check firstConfirm the part fits the travel before quoting cycle time.
• 4
  Mill-turn for hybridsTurned bores plus milled features stay in one spindle.

Our standard tolerance on critical dimensions is ±0.005 mm (±0.0002 in). That is a capability statement, not a default. Applying it to every dimension on a drawing raises cost and inspection time without improving function. Good drawings mark the two or three dimensions that carry the fit, and let the rest sit at general tolerances.

Surface finish and tolerance are linked. A tight bore with a rough wall will not hold a press fit reliably, and a very fine finish on a non-functional face is wasted money. We work to Ra 0.2–0.8 μm for fine finishes, Ra 0.8–1.6 μm for high-finish surfaces, and Ra 1.6–3.2 μm as-machined. Tell us which surfaces seal, slide or mate, and the rest can stay as-machined.

Thin walls and long overhangs are the usual offenders. A 0.5 mm wall in aluminium will deflect under normal cutting force, so we reduce depth of cut and accept a longer cycle. Titanium and Inconel behave differently again: heat stays in the cut, tools wear faster, and the same feature that takes minutes in 6061 can take much longer in Ti-6Al-4V.

We check raw material on arrival, monitor in-process, and inspect 100% before shipment, with reports on request. Historical qualification rate is 99.99%. If a feature cannot be measured the way the drawing calls it out, we raise that during DFM review rather than after machining.

We machine aluminium 6061, 6061-T6, 2024, 5052, 5083, 6063, 6082, 7075 and ADC12; stainless 303, 304, 316, 316L, 420, 430, 431, 440C and 17-4PH (SUS630); steels 1018, 1045, 4130, 4140, 4340, A36 and tool steel; copper and brass including C101, C103, C110, beryllium copper, C27400, C28000 and C36000; titanium TA1, TA2, TC4 (Ti-6Al-4V), Inconel and magnesium AZ31B / AZ91D; plus plastics ABS, PC, PMMA, POM, PA, PEEK, PP, HDPE and carbon fibre.

The choice is rarely about strength alone. 7075 machines well and holds tolerance, but it is less corrosion resistant than 6061 unless it is anodized. 303 stainless is free-machining and good for high-volume small parts; 316L is the one to pick when the part sees salt or sterilisation. 17-4PH gives you strength after heat treatment, but the heat treat move has to be planned into the sequence, because the part will shift.

Plastics bring their own rules. PEEK and POM move with temperature, so rough machining followed by a stress-relief pause and a finish pass holds size better than one heavy cut. Carbon fibre eats tool edges, so we plan tool changes rather than pushing a worn cutter.

Finishing is part of the material decision. We offer anodizing (clear, colour, hardcoat, conductive), electroless nickel, zinc, silver and gold plating, powder coating and black oxide, plus bead blasting, tumbling, brushing and polishing. Laser marking and engraving go down to a minimum character height of 1.5 mm, which is worth knowing before you put a 0.8 mm part number on a face.

Quotation and a free DFM analysis come back within 12 hours. The DFM note is where we flag a wall that is too thin, a corner radius smaller than the cutter can reach, or a tolerance that cannot be inspected as drawn. Production can start within 24 hours of approval, and parts ship in 3–5 days. Historical late-delivery probability is below 2%.

There is no minimum order quantity. One prototype and a 10,000+ part run use the same first step: read the drawing, pick the machine, plan the setup. For prototypes the goal is to learn whether the design works. For production the goal is repeatability, so fixtures and inspection plans get locked before the run starts.

Certifications cover the industries we serve: ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. Material certification (MTRs) and RoHS/REACH compliance are standard. Uploads are secure and confidential, and an NDA is available on request.

We are based in Dongguan, China, with a factory in Singapore at No.3 Joo Koon Circle, Singapore 629032. That second site shortens the supply line for customers who need parts closer to Southeast Asia.