Enclosure failures are usually material failures: a housing that cracks at the screw bosses, turns yellow outdoors, warps near a hot component, or fails the flame test needed for certification. Choosing the resin early — before tooling — avoids expensive surprises.
Common enclosure plastics compared
| Material | Strengths | Weaknesses | Typical use |
|---|---|---|---|
| ABS | Easy to mold, good surface finish, paintable, economical | Limited UV resistance and heat resistance | Indoor consumer and electronic housings |
| PC (polycarbonate) | Very high impact strength, higher heat resistance, available transparent | Sensitive to some chemicals and stress cracking; can scratch | Rugged housings, lenses, light covers |
| PC-ABS | Balance of PC toughness and ABS processability | Costs more than ABS | Laptop-style housings, chargers, handheld devices |
| ASA | Like ABS but much better UV and weather resistance | Fewer grades and colors stocked | Outdoor housings, sensors, garden products |
| PA6 / PA66 (+glass fiber) | Strong, stiff, heat- and wear-resistant | Absorbs moisture (dimensions change), harder cosmetics | Structural brackets, clips, functional parts |
| PP | Chemical resistant, living hinges, low cost | Hard to bond or paint, lower stiffness | Containers, lids, pet and household products |
Questions that decide the material
- Where is it used? Outdoor and UV exposure → ASA, UV-stabilised PC, or a UV-stable coating.
- How hot does it get? Near power electronics or in sunlight behind glass → PC or PC-ABS rather than ABS; check the grade’s heat deflection data.
- Does it need a flame rating? Many mains-powered products require UL 94 V-0 or similar for enclosures — choose a flame-retardant grade listed for the wall thickness you use.
- Will it be dropped? PC and PC-ABS absorb impact best.
- What chemicals touch it? Cleaners, oils and sunscreen can stress-crack PC; test with real chemicals.
- What should it look like? ABS and PC-ABS give the most consistent textured or glossy finishes; glass-filled PA shows fibers on the surface.
- Food or skin contact? Use certified grades and keep the documentation.
Design for the material
- Keep wall thickness uniform; sudden changes cause sink marks and warping.
- Design screw bosses with the resin supplier’s guidance — cracked bosses are the most common ABS/PC failure.
- Add draft angles so textured surfaces release from the mold.
- For IP-rated enclosures, design gasket grooves or welding features with the material in mind (ultrasonic welding works well on ABS and PC).
- Specify the exact grade (manufacturer and grade name, or equivalent with documented properties), color reference and flame rating on the drawing.
Material choice also affects mold cost and cycle time — see injection mold cost explained. For connected devices, plastic choice affects antenna performance — see IoT hardware manufacturing. Or send your enclosure design for a material and DFM review.