Lighter parts mean lower freight, lower material cost per part and, in vehicles, better efficiency. Resin choice is one of the biggest levers.
Density matters more than people expect
Resin is bought by the pound but parts are made by volume, so a lower-density resin gives you more parts per pound.
| Resin | Typical density (g/cm³) |
|---|---|
| Polypropylene | ~0.90 |
| Polyethylene | ~0.92–0.96 |
| ABS | ~1.04 |
| Nylon 66 | ~1.14 |
| Polycarbonate | ~1.20 |
| PBT | ~1.31 |
| Glass-filled nylon 66 (30%) | ~1.36 |
| Acetal | ~1.41 |
Typical values; check the data sheet for your grade.
Ways to cut weight
- Talc-filled PP instead of ABS in some housings and interior parts: lower density and lower cost per part.
- Carbon fiber instead of glass: the same stiffness with less filler, so a lighter part. Carbon-filled nylon & PP
- A stiffer grade with thinner walls: often saves more weight than a change of resin.
- Plastic instead of metal altogether. Replacing metal with plastic