01
Melted edges and gummy chips
A cutter sized for aluminum turns POM or HDPE into a smear. The edge burrs, the chip welds back onto the wall, and the dimension reads oversize after cooling. You get parts that need hand rework or scrap.
Plastic Machining
Precision CNC Plastic Machining for Functional Plastic Parts
We machine ABS, PC, POM, PEEK, PA, PP and HDPE from one prototype to 10,000+ parts. Quote and DFM analysis inside 12 hours, ±0.005 mm tolerance, 100% inspection before shipment.
±0.005 mm toleranceNo MOQ12-hour quote16 five-axis centers3–5 day shippingISO 9001:2015
±0.005 mmAchievable tolerance on plastic parts
16Simultaneous 5-axis machining centers
127High-precision CNC machines on site
15 yearsMachining plastics since 2011
Where plastic parts go wrong
Four Failures We See Every Month
Most rejected plastic parts fail for mechanical reasons, not for the drawing.
02
Wall flex during clamping
Thin-wall PC or ABS housings deflect under vise pressure. The part measures correctly in the machine and springs back out of tolerance once unclamped. Assembly then needs shimming.
03
Heat growth after a long run
Plastic expands roughly ten times more than steel. A batch cut on a warm afternoon can drift 0.05 mm from the morning parts. Mixing the two in one assembly creates fit problems.
04
Threads that strip on first use
A cut thread in unfilled nylon holds less load than the drawing implies. Buyers find out at assembly, when the screw pulls out. A metal insert or a coarser pitch solves it, but only if someone flags it before the run starts.
How we machine plastics
Cutting Parameters Built Around the Material, Not the Machine
Same geometry, different feeds, tools, and hold-down for every resin.
Tooling and Feeds
Tool Geometry and Feeds Chosen per Resin
Soft and glass-filled plastics behave nothing alike at the cutting edge. We keep separate tool libraries for each family: two-flute polished carbide for acrylic and PC, straight-flute or O-flute for POM and HDPE so the chip clears instead of packing, diamond-coated tools for carbon fibre and glass-filled PA.
Spindle speed, feed per tooth, and depth of cut are set from the resin datasheet plus a test cut. On PEEK we run higher surface speed and lighter radial engagement to keep heat in the chip. On HDPE we slow down and take bigger passes, because rubbing is what melts the wall.
- 1Two-flute polished carbideAcrylic, PC, PMMA. Clean shear, no clouding.
- 2O-flute and straight flutePOM, HDPE, PP. Chip evacuation without welding.
- 3Diamond-coated toolingCarbon fibre and glass-filled PA. Holds edge life.
Fixturing
Workholding That Does Not Distort the Part
Plastic gives back the energy you put into it. Clamp a 1.5 mm PC wall in a standard vise and it will measure correctly under load, then spring open when the jaws release. We design soft jaws, vacuum chucks, and dedicated fixtures around the actual part stiffness.
For large flat panels we use vacuum beds so the load spreads over the whole face. For thin ribs and long slender parts we add support material or machine them in two operations, flipping once the first side is stable. On parts under 200 mm we often finish the critical faces in a single setup to avoid re-datum error.
- 1Soft jaws and vacuum bedsPressure spread over the face, not the edge.
- 2Two-operation flipLong parts stay supported while the second side cuts.
- 3Single-setup finishingCritical faces cut without re-datum error.
Material Selection
Which Plastic for Which Job
A quick guide to the resins we run most often.
| Resin | Best for | Watch out for |
|---|---|---|
| ABS | Housings, brackets, low-cost prototypes | Low stiffness, poor chemical resistance |
| PC | Impact covers, guards, clear lenses | Stress cracking near solvents, needs annealing |
| POM | Gears, bushings, sliding parts | Hard to bond, warps on thick sections |
| PEEK | High-temperature and wear parts | Expensive, needs sharp tooling and coolant |
| PA (nylon) | Wear strips, clips, structural parts | Absorbs moisture, dimensions move after cutting |
| HDPE | Chemical tanks, low-friction liners | Very soft, flexes under light clamping |
| PMMA | Optical windows, display covers | Brittle at edges, chips on heavy cuts |
| PTFE | Seals, chemical contact parts | Cold flow under load, hard to hold tolerance |
What we run
Services Around Plastic Parts
Machining is the core. These are the steps that come with it.
01
3-Axis Milling
Flat plates, covers, and prismatic housings up to 4,000 mm. The workhorse for most plastic parts.
02
4-Axis Milling
Multiple faces on one part without a second fixture. Good for long extrusions with features on four sides.
03
5-Axis Machining
Contoured surfaces, undercuts, and complex housings. 16 simultaneous centers available for plastic work.
04
CNC Turning
Bushings, rollers, spacers, and threaded inserts. Mill-turn centers handle parts that need both operations.
05
Rapid Prototyping
One-off and low-volume plastic parts for fit checks before tooling is committed.
06
Surface Finishing
Bead blasting, tumbling, polishing, and laser marking sized for plastic surfaces.
Capability
Plastic Machining Scope
Numbers you can plan around.
| Item | Specification | Notes |
|---|---|---|
| Tolerance | ±0.005 mm | Typical on rigid resins |
| Surface finish | Ra 0.2–0.8 μm | Polished tool and light finishing pass |
| Max part size | 4,000 mm | Long panels and extrusions |
| 5-axis travel | 4,000 × 400 × 150 mm | Large contoured parts |
| Minimum order | 1 part | No MOQ, up to 10,000+ runs |
| Quote turnaround | 12 hours | Includes free DFM analysis |
| Production start | 24 hours | After drawing release |
| Shipping | 3–5 days | Standard part runs |
Why GreatLight
What You Get With the Parts
Numbers instead of adjectives.
15Y
15 Years in Machining
Founded in 2011. Three wholly-owned plants and 150 technicians in Dongguan and Singapore.
127
127 CNC Machines
16 simultaneous 5-axis centers, 12 four-axis mills, 27 three-axis machines, 16 mill-turn centers.
±0.005
Tight Tolerance
±0.005 mm (0.0002 in) on rigid plastics, verified with in-process monitoring.
12h
Fast Quote
Quotation and free DFM analysis returned within 12 hours of receiving your files.
100%
Full Inspection
Every part checked before shipment. Raw material, in-process, and final inspection.
4
Certifications
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, ISO 27001:2022.
7,600 m²Manufacturing space across three plants
150Technicians on the shop floor
99.99%Qualification rate on shipped parts
<2%Historical late-delivery probability
Applications
Plastic Parts by Industry
Automotive and EV
Bumper trim, sensor housings, and under-hood brackets cut from ABS, PC-ABS, and PA.
- IATF 16949
- ±0.005 mm
- 100% inspection
Consumer and Tooling
Handles, jigs, and fixtures in POM and HDPE where sliding wear matters more than stiffness.
- No MOQ
- 3–5 day ship
- Ra 0.8–1.6 μm
Robotics and Automation
End-effector jaws, covers, and cable guides in PEEK and PA for light weight and low friction.
- 5-axis
- ±0.005 mm
- 150 technicians
Medical Devices
Housings, manifolds, and instrument covers in PC, PEEK, and PMMA. Clean cuts, no contamination.
- ISO 13485
- ±0.005 mm
- 100% inspection
FAQs
Questions Engineers Ask Before Ordering
Which plastics can you machine?
We run ABS, PC, PMMA, POM, PA, PEEK, PP, HDPE, and carbon fibre on a regular basis. Each resin gets its own tool set and cutting parameters, because a feed that works on POM will melt HDPE.
If your material is not on the list, send the datasheet. We will tell you whether it cuts cleanly or whether another resin does the same job for less.
What tolerance can you hold on plastic?
±0.005 mm (0.0002 in) is realistic on rigid, unfilled resins such as POM, PC, and PEEK. That figure applies to critical features, measured at 20 °C.
Soft materials like HDPE and PTFE move more after cutting. On those we quote a looser band and flag the features that will drift. Telling you early is cheaper than a rejected batch.
How much does a plastic part cost compared to aluminum?
The machining time is often similar. The material price is the variable. PEEK and carbon fibre cost far more per kilogram than 6061 aluminum, while ABS and HDPE are cheaper.
We quote both options when the design allows it. Many brackets that were drawn in PEEK work fine in PA at a fraction of the material cost.
Can you make a single prototype?
Yes. There is no minimum order quantity. We have run one-off parts and production runs above 10,000 pieces on the same floor.
For a first article, expect a quotation and DFM feedback within 12 hours and shipping in 3–5 days after drawing release.
How do you stop thin walls from flexing?
We design the fixture around the part, not the other way around. Soft jaws, vacuum chucks, and support material take the clamping load off thin ribs and walls.
Where a part is too flexible for one setup, we machine it in two operations and flip it once the first side gives it rigidity. Critical faces are finished in a single setup wherever the geometry allows.
Do you anneal plastic parts after machining?
We do when the resin needs it. PC and PEEK both relieve internal stress better after a controlled anneal, and that reduces the chance of cracking in service or during a solvent wipe.
Tell us the operating conditions. If the part sees heat, chemicals, or a press fit, an anneal cycle is usually worth the extra day.
What files do you need for a quote?
Send a STEP or IGES model plus a 2D drawing with tolerances, material, and finish called out. If you only have a model, we will mark the features that need a tolerance call before cutting.
Uploads stay confidential and an NDA is available on request.
How do you handle color and surface finish on plastic?
Most plastic parts are cut from colored stock, so the finish comes from the sheet, not from a coating. We can bead blast, tumble, or polish to change the surface texture.
Laser marking works on most resins with a minimum character height of 1.5 mm. On transparent PC and PMMA, laser marking can cloud the surface, so we usually mask and engrave instead.
Send Your Plastic Part for a Quote
Upload a STEP file and drawing. You get a quotation and free DFM analysis within 12 hours, no minimum order quantity, and 100% inspection before shipment.
12-hour quote100% inspectionNo MOQNDA on request
