CNC Plastic Machining
Machined plastic prototypes and production parts in seven engineering plastics, from one piece.
- 7 plastics
- POM, PA, PEEK, PC, ABS, PTFE, UHMW
- 0.8–0.9×
- Delrin cost vs 6061 aluminum
- No mold
- Machined from plate and rod
- From 1 pc
- No minimum order
Machining makes real engineering-plastic parts with no tooling, so it fits prototypes and runs too small for a mold. Delrin is the usual first choice: stable, slippery and quick to cut. PEEK covers heat and chemicals; UHMW and PTFE cover wear and low friction.
Commonly used for:
- Gears, bushings and wear parts
- Insulators and spacers
- Fixtures and nests
- Clear covers and windows
- Pre-mold prototypes
What we make in plastic
Functional plastic parts that must slide, insulate or resist chemicals.
Gears and bushings
Delrin and nylon parts that run without lubrication.
Wear strips and guides
UHMW-PE liners, rails and slides for conveyors.
Insulators and spacers
Electrical and thermal breaks in PEEK, PTFE or POM.
Fixtures and nests
Soft-touch locators that do not mark the parts they hold.
Clear parts
Polycarbonate covers, windows and light pipes.
Seals and valve seats
PTFE and PEEK parts for fluids and chemicals.
Plastic machining capabilities
What the standard order holds. Tighter values are quoted per feature from your drawing.
Tolerances
Plastics grow with heat and, for nylon, with moisture. Soft plastics such as UHMW and PTFE need wider tolerances; keep tight ones to fits.
Part size
Plastic plate and rod sizes set the practical limit; large parts are reviewed by an engineer.
Walls
A published starting value for plastic walls, not a limit. Thin plastic walls flex under the cutter and warp as stress releases.
Cost
Delrin is cheaper than aluminum. PEEK is the exception: the stock itself costs like a specialty alloy.
| Plastic | Cost vs 6061-T6 |
|---|---|
| Delrin (POM) | 0.8–0.9× |
| PEEK | 2–3× |
Threads
Plastic threads wear quickly. Call out heat-set or helical inserts where screws go in and out.
Finish
Polycarbonate can be polished for clarity on request. Tool marks stay visible on other plastics.
Inspection
Dimensional reports and material certificates are available on request.
Plastics
Each links to its datasheet with properties and typical uses.
Low friction and wear
High performance
Compare grades side by side
| Material | Machinability | Cost | Use it for |
|---|---|---|---|
| POM-C | Excellent | $$ | Chemical-resistant gears; Bearings and bushings; Slide plates and wear guides |
| PA6 | Very good | $ | Automotive gears; Pulleys; Caster wheels |
| ABS | Excellent | $ | Electronic enclosures and housings; Power tool housings; Computer keyboards |
| PC | Very good | $ | Machine guards and safety shields; Clear windows and glazing panels; Lighting lenses and light pipes |
| PEEK | Very good | $$$$$ | Spinal fusion implants; Aerospace seals and back-up rings; Downhole oil and gas seals |
| PTFE | Good | $$$ | Seals; Gaskets; Liners |
| UHMW-PE | Fair | $$ | Chute and hopper liners; Conveyor wear strips; Conveyor guide rails and curves |
Machinability and weldability are the library’s 0–100 scores (Excellent ≥ 85 … Poor < 35); cost is the relative tier, not a price. Every grade links to its datasheet with tempers, heat treatments and the finishes it takes.
Which plastic?
Start with Delrin and move only when heat, chemicals or wear demand it.
| Plastic | Known for | Watch out for |
|---|---|---|
| Delrin (POM)default | Stiff, stable and slippery; the easiest plastic to hold tight. | Hard to glue or bond. |
| Nylon 6tough | Tough and wear resistant; good for gears. | Absorbs water and grows; tolerances drift. |
| PEEKheat, chemicals | Strength and chemical resistance well above 200 °C. | Stock price; quote it only where it is needed. |
| Polycarbonateclear, impact | Clear and very impact resistant. | Scratches; stress cracks with some solvents. |
| UHMW-PE / PTFElow friction | Very low friction and chemical resistance. | Soft; hard to hold tight tolerances. |
How to order
- 1Upload a STEP file.Pick the plastic, finish and quantity. Add a PDF drawing for tolerances and threads.
- 2Review price and DFM.Standard and expedited ship dates side by side for your exact part.
- 3Order online.Every order is first-article inspected before it ships.
Questions about CNC plastics
Which plastic is best for CNC machining?
Delrin (POM). It is stiff, dimensionally stable and cuts cleanly, so it holds tolerances better than most plastics. It is also cheaper than aluminum for the same part.
Is machined plastic cheaper than aluminum?
Delrin usually costs about 0.8–0.9× the same part in 6061 aluminum. PEEK costs about 2–3×, because the stock is expensive.
Machining or 3D printing for plastic parts?
Machine when you need a specific engineering plastic, tight tolerances or a smooth finish. Print when the shape has internal features or you need many design iterations quickly.
When should I switch to injection molding?
Usually past a few hundred identical parts, once the design is frozen. Machining has no tooling cost, so it wins for prototypes and small runs.
Can you machine clear parts?
Yes, in polycarbonate. Machined faces come out translucent; ask for polishing on the faces that must be clear.
Price your plastic part now
Upload a STEP file and get a price, ship date and DFM notes in minutes.