Engineering Plastics for CNC, Injection Moulding and 3D Printing
When your part must be light, electrically insulating, low-friction or impact resistant, engineering plastics are the right answer. At SkillsProto we work with ABS, polycarbonate (PC), POM (Delrin), nylon (PA), PEEK and filled grades — across CNC machining, injection moulding and 3D printing.
Engineering plastics cover most of the property combinations you need without the weight or corrosion risk of metals.
Common engineering plastics at a glance
| Material | Key Properties | Best For |
|---|---|---|
| ABS | Tough, easy to finish, paintable | Enclosures, consumer products, prototypes |
| PC (Polycarbonate) | Impact resistant, transparent | Lenses, covers, safety equipment |
| POM (Delrin / Acetal) | Low friction, high stiffness, dimensional stability | Gears, bearings, precision parts |
| PA (Nylon 6 / 6.6) | Wear resistant, strong, slight moisture absorption | Bushings, structural clips, gears |
| PA + GF (glass-filled) | Stiffer, lower thermal expansion | Automotive under-bonnet, structural |
| PEEK | High temperature (up to 260°C), chemical resistant | Aerospace, medical, oil & gas |
| PE (HDPE / LDPE) | Chemical resistant, low friction | Tanks, liners, food-grade parts |
| PMMA (Acrylic) | Glass-clear, scratchable | Display, light guides, cosmetic covers |
When to choose each material
- ABS — general-purpose enclosures; paintable; not for high-stress or outdoor UV.
- PC — impact-critical or transparent parts; needs UV protection for outdoor use.
- POM (Delrin) — precision moving parts, gears, bearings; absorbs moisture less than nylon.
- Nylon (PA) — wear-resistant structural parts; consider glass-filled for stiffness.
- PEEK — high-temperature or sterilisation applications (medical, aerospace).
- PMMA — cosmetic transparent parts; scratch-resistant coatings available.
Process options
- CNC machining — for prototypes and small batches (1–200). Tight tolerances, no tooling cost.
- Injection moulding — for 1,000+ volume production. Tooling amortised over the volume.
- 3D printing (SLA / SLS / MJF) — for complex geometry, internal channels, very low volumes (1–10).
CNC machining notes
- Engineering plastics machine easily with sharp tools and moderate speeds.
- Tolerances to ±0.05 mm achievable on critical features.
- POM and PA can absorb moisture — parts may need conditioning before tight-tolerance measurement.
- Lead time 3–7 working days for CNC prototypes.
Frequently Asked Questions
Q1: Which engineering plastic is best for food-contact parts? A: HDPE, POM and certain grades of PA and PC meet FDA / EU food contact. We will specify the resin grade on your quote.
Q2: Can engineering plastics be used outdoors? A: Yes with UV-stabilised grades. ABS and standard PC yellow under UV; UV-stabilised grades are available.
Q3: What's the strongest engineering plastic you machine? A: PEEK is the strongest commonly machined engineering plastic, with continuous service temperature up to 260°C.