Custom Plastic Machining
DEK offers custom plastic machining in 15 engineering polymers, from PEEK and PTFE to Delrin and nylon, held to ±0.01 mm in the same shop that machines your metal parts.
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15Polymers
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±0.01mmTolerance
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No MOQAny Quantity
Why DEK for Custom Plastic Machining
DEK machines plastic parts in the same factory, with the same engineers and inspectors, as your metal parts, so an aluminum housing and a PEEK insulator are quoted, machined, inspected and shipped as one order. Metal stays the core of the shop; see CNC machining metals.
Shortlist a polymer on temperature, chemical exposure and load, or send those conditions and an engineer will recommend one. Parts run on our milling, turning and Swiss equipment.
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One Shop, One Order
Same engineers and inspectors as metal, since 2002
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±0.01 mm Standard
Verified on CMM with inspection temperature noted
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15 Polymers Stocked
PEEK to G10, material certificates on request
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Certified Quality
ISO 9001:2015, ISO 13485, AS9100D, by TÜV
CNC Machining Plastics We Stock
From PEEK and PTFE for heat and chemicals to Delrin and nylon for wear, every polymer is stocked and held to ±0.01 mm, with no MOQ.
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ABSNatural, black, flame-retardant (UL 94 V-0) and PC/ABS grades machined to ±0.01 mm for enclosures, bezels, fixtures and appearance prototypes.View Grades -
DelrinAcetal homopolymer (Delrin 150) and copolymer for gears, bushings, valve bodies and food-contact parts: clean chips, low moisture, ±0.01 mm typical.View Grades -
FR4UL 94 V-0 glass-epoxy laminate for test fixtures, probe plates, insulators and spacers. FR-4, High-Tg FR-4 and FR-5 / G-11, held to ±0.01 mm.View Grades -
Garolite G-10Garolite G-10 glass-epoxy laminate for insulators, cryogenic supports, fixtures and knife handles: 20 kV/mm dielectric strength, near-zero moisture uptake.View Grades -
NylonTough, quiet, self-lubricating PA6, PA66, 30% glass-filled and MoS2 nylon for gears, bushings, wear pads, rollers and insulators.View Grades -
PEIUnfilled Ultem 1000 and 30% glass-filled Ultem 2300 PEI for test sockets, sterilization trays and aircraft brackets: 170 °C continuous, UL 94 V-0.View Grades -
PMMA AcrylicCast and extruded PMMA machined into optically clear lenses, light guides, fluidic manifolds and display covers, polished back to 90%+ light transmission.View Grades -
PolycarbonateTransparent, impact-tough plastic: optical clear, glass-filled, FDA and UL 94 V-0 grades for machine guards, sight glasses, lenses and housings.View Grades -
PolyethyleneUHMW-PE and HDPE: the lowest-friction, most abrasion-resistant commodity plastic, FDA compliant in natural grades, for wear strips and chain guides.View Grades -
PTFEPTFE (Teflon) for low-friction, chemically resistant parts: virgin, glass-, carbon- and bronze-filled grades for seals, bushings and insulators.View Grades -
POM(Delrin)View Grades -
PEEKPEEK machined in unfilled, 30% glass-filled, 30% carbon-filled and bearing grades for medical, aerospace and semiconductor parts.View Grades
Need a metal instead? Browse our CNC machining metals.
Plastic Selection Table
Plastics creep, swell with moisture and soften with heat: shortlist on max temperature, chemical resistance, wear and cost first.
| Plastic | Max temp | Chemicals | Wear | Cost |
|---|---|---|---|---|
| PEEK | 250 °C | Excellent | Excellent | Very high |
| PTFE | 260 °C | Excellent | Excellent | High |
| Delrin / POM | 90 °C | Good | Excellent | Low–medium |
| Nylon | 100 °C | Good | Very good | Low |
| PMMA / acrylic | 80 °C | Fair | Fair | Low |
| Polycarbonate | 120 °C | Fair | Fair | Low–medium |
| PEI / Ultem | 170 °C | Very good | Good | High |
| UHMW / HDPE | 80 °C | Excellent | Excellent (UHMW) | Low |
| PP | 100 °C | Excellent | Fair | Low |
| PET | 110 °C | Good | Good | Low–medium |
| PPSU | 180 °C | Very good | Good | High |
| FR4 | 130 °C | Good | Fair | Medium |
Design Rules for Plastic Machined Parts
Plastics move with temperature, humidity and load; these rules keep machined features in tolerance after delivery.
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1
Tolerances
±0.01 mm is DEK’s standard on plastics; apply it only to fits and mating features and leave the rest at ISO 2768-m, since plastics move with temperature and humidity.
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Thermal Expansion
Most polymers expand 5–10 times more than steel: a 200 mm Delrin plate grows about 0.2 mm over a 10 °C rise. Specify the inspection temperature (20 °C) on the drawing.
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3
Moisture Absorption
Nylon absorbs 2–3% water and grows with it. Specify conditioned or dry state, or choose Delrin or PET for tight tolerances.
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4
Stress and Creep
Use internal radii of 0.5 mm or more and avoid thin walls under sustained load. PTFE and PE creep under clamping: design retaining features, not press fits.
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5
Wall Thickness and Flatness
Keep walls at 1.5 mm or more. Thin plates distort from residual stock stress, so DEK rough-machines, rests, then finishes flat parts.
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Threads in Soft Plastics
Use coarse threads or metal inserts in soft plastics. Fine threads cut in PTFE or PE strip easily, so reserve them for stiffer polymers.
Custom Plastic Fabrication, by Family
Machined in the production-grade polymer, our plastic prototyping services deliver functional parts in 3–5 days; each family page details its grades.
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PEEK machiningThe highest-performance polymer in the shop: semiconductor wafer handling, medical instruments and bushings that replace metal at high temperature. -
PTFE machiningChemically inert and self-lubricating but soft; machined with sharp tooling and light clamping to hold ±0.01 mm on seals and liners. -
PEI (Ultem) machiningUltem 1000 and glass-filled Ultem 2300 for flame-rated electrical parts, aerospace interiors and repeat-sterilization trays. -
Delrin (POM) machiningThe most precise-machining plastic, for gears, cams and bushings; Delrin AF adds PTFE for lower friction, glass-filled grades add stiffness. -
Nylon machiningNylon 6 and 6/6, plain and glass-filled, for rollers, wear pads and structural parts; allow for moisture absorption on tight tolerances. -
Polyethylene (PE) machiningUHMW-PE suits wear strips, chain guides and food-contact parts; HDPE suits tanks and low-cost fixtures. -
PMMA (acrylic) machiningOptical clarity for windows, covers and light guides; polishing or vapor polishing restores transparency after machining. -
Polycarbonate machiningHigher impact resistance than acrylic for guards and housings, at slightly lower clarity, when a transparent part must take impacts. -
FR4 and G10 machiningGlass-epoxy laminates for insulators and test fixtures, machined with carbide tooling and dust extraction.
Frequently Asked Questions
Common questions on tolerances and difficult polymers in custom plastic machining.
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