Option A
ABS
- Often considered for molded indoor housings
- Texture and secondary finish options depend on grade
- Impact properties vary by grade and temperature
- Check heat and UV exposure before selection
Technical Resource
Plastic Materials Technical Guide
Engineering properties, mechanical strengths and design considerations for commonly specified thermoplastic resins.
Choosing a resin starts with the application
The right plastic depends on load, temperature, chemical exposure, appearance and cost. This guide covers resins buyers commonly compare before a mold is built.
Values here are typical published figures for unfilled general-purpose grades. Fillers, additives and moisture change them a lot, so the final grade is agreed against the resin datasheet and your drawing.
- Written for engineers and sourcing teams
- Typical values, not guaranteed minimums
- Final grade confirmed at quotation
Plastic parts and process details
Illustrative photos show shapes and tooling questions to discuss, not completed client work.
-
Gate and surfaceGate position affects appearance, filling and trimming. -
Clips and cutoutsCheck wall thickness, snap fit and tooling access early. -
Part in contextMaterial selection also depends on neighboring parts and assembly loads.
ABS vs PC vs PA66 vs POM vs PP
| Resin | Density | Tensile | Max service | Shrinkage |
|---|---|---|---|---|
| ABS | 1.05 g/cm3 | 40-50 MPa | 70-85 °C | 0.4-0.7% |
| PC | 1.20 g/cm3 | 60-70 MPa | 115-125 °C | 0.5-0.7% |
| PA66 | 1.14 g/cm3 | 75-85 MPa | 80-120 °C | 1.0-2.0% |
| POM | 1.41 g/cm3 | 60-70 MPa | 85-105 °C | 1.8-2.2% |
| PP | 0.90 g/cm3 | 25-35 MPa | 80-100 °C | 1.0-2.5% |
Resin selection methodology
Compare service conditions first, then review candidate grades against current supplier data and the part drawing.
Impact and toughness
Compare impact data for candidate ABS and PC grades under the expected temperature, thickness and loading.
Heat
Review the continuous-use temperature and heat-deflection data for the selected grade under the actual load.
Wear and sliding
POM for gears, cams and latches; PA66 for bushings and clips that see higher loads.
Chemicals and moisture
Check chemical compatibility for the exact concentration and temperature. Account for moisture-related dimensional change in PA66.
Appearance
ABS takes texture, paint and plating well. PC and PMMA cover clear parts.
Regulated use
State food contact, flame rating such as UL 94 V-0, or medical use at quotation.
- ABS
- PC/ABS
- Polycarbonate
- PA66 GF30
- POM
- PBT GF30
- PP copolymer
- HDPE
- PMMA
- TPE
- TPU
Resin-specific benefits and cautions
| Resin | Strengths | Watch for | Typical parts |
|---|---|---|---|
| ABS | Tough, easy to mold, plates | Poor UV and heat | Housings, trim |
| PC | Impact, clarity, heat | Stress cracking, scratches | Lenses, guards |
| PC/ABS | Tough, more heat than ABS | Costs more than ABS | Electronic housings |
| PA66 | Strong, wear resistant | Absorbs moisture | Clips, bushings, gears |
| POM | Low friction, stable | Acids; hard to bond | Gears, latches, rollers |
| PP | Chemical resistant, light | Warps; hard to paint | Caps, hinges, tanks |
| PBT | Electrical, chemical | Brittle unfilled | Connectors, sensors |
| PMMA | Clarity, weathering | Brittle | Light guides, covers |
| TPE / TPU | Soft touch, flexible | Bond must be tested | Seals, grips, overmolds |
ABS or polycarbonate
Common candidates for housings and covers.
Option B
Polycarbonate
- Often considered where impact or heat matters
- Clear grades are available for lenses and windows
- Snap-fit design requires grade-specific strain review
- Some chemicals can cause stress cracking
Compare candidate ABS, PC and PC/ABS grades against impact, heat, appearance, chemical exposure and current pricing.
Resin families and common grades
Typical starting points. Availability and grade are confirmed per project.
Housing and general purpose
Enclosures, covers and containers.
- ABS
- PC/ABS
- PP homopolymer
- PP copolymer
- HDPE
- LDPE
Engineering resins
Wear, strength and moving parts.
- PA6
- PA66
- PA66 GF30
- POM copolymer
- POM homopolymer
- PBT GF30
Transparent resins
Lenses, light guides and covers.
- PC
- PMMA
- Clear PS
Flexible and soft-touch
Seals, grips and overmolds.
- TPE
- TPU
- TPV
Design notes
Rules of thumb for early design. Typical values, confirmed per resin and part.
- Wall thickness
- About 1 to 3.5 mm for these resins; keep it as uniform as possible
- Draft angle
- At least 1 degree on faces in the direction of pull; more on textured faces
- Ribs
- About 50 to 60% of the wall they support, to avoid sink marks
- Tolerance
- Confirm against resin grade, part geometry and tooling plan
- Shrinkage
- Built into the mold steel per resin; changing resin later can mean recutting
- Drying
- PA66, PC and PBT are dried before molding to avoid splay and brittle parts
- Mold class
- Confirm against resin grade, part geometry and tooling plan
- Outdoor use
- Specify UV-stabilized grades at quotation
Plastic material questions
Why do nylon parts change size?
PA66 absorbs moisture from the air after molding. It gets tougher but swells slightly and loses some stiffness. Design fits for the conditioned state, or choose POM where tight dimensions matter in humid service.
What does glass fill do?
Glass fiber, often 30% (GF30), raises stiffness, strength and heat resistance. It also makes shrinkage uneven, so parts can warp, and it wears the mold faster. Gate position and tool steel are chosen with this in mind.
Can an existing part help identify a resin?
A sample and its application can inform material selection, but visual inspection alone cannot establish an exact resin grade. Supplier data or material testing may be needed before tooling decisions.
Does the resin affect tooling cost?
It can. Abrasive, filled or corrosive resins need harder or treated tool steel, and shrinkage differs between resins. We discuss this in the design review.
Can parts be colored to a specific match?
Color matching may be possible with masterbatch or pre-colored resin. Feasibility, tolerance and approval samples are agreed per project.
Is recycled or bio-based resin an option?
It can be, depending on the grade and the performance needed. Ask at quotation and we advise on availability and trade-offs.
Not sure which resin fits?
Send your drawing and intended service conditions for a material and molding-risk review during quotation.
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