PC Injection Molding: Properties, Grades, Applications and DFM Notes

Mon, 19 Oct 2026 00:00:00 +0000

What PC Is — and What It Is Not

Polycarbonate is an amorphous engineering thermoplastic. Amorphous matters more than the chemistry here: PC has no crystalline melting point, so it shrinks little and predictably (0.5–0.7 %), holds tight tolerances well, and stays optically clear. Those three properties are why PC ends up in lenses, medical housings and transparent covers rather than in structural brackets.

What PC buys you over the cheaper styrenics is impact strength. At 600–900 J/m notched, room-temperature PC is roughly three to four times tougher than ABS (150–250 J/m), and it stays ductile far lower: about −30 °C unnotched and −10 °C notched, with no sharp ductile-to-brittle transition of the kind that makes ABS fail suddenly in cold service.

ABS Injection Molding: Properties, Grades, Applications and DFM Notes

Wed, 14 Oct 2026 00:00:00 +0000

What ABS Is — and What It Is Not

ABS is a terpolymer of acrylonitrile, butadiene and styrene. The acrylonitrile contributes chemical resistance and rigidity, the butadiene contributes impact strength, and the styrene contributes surface finish and processability. Tuning those three ratios is what produces the different grade families below — which is why “ABS” on a drawing is not a specification.

Two things ABS is not:

It is not a high-temperature material. Heat deflection sits at 85–100 °C. Above that, dimensional stability and load-bearing capacity fall away quickly.
It is not a low-temperature material. The butadiene phase that gives ABS its impact strength at room temperature undergoes a ductile-to-brittle transition as it cools. At −40 °C pure ABS is effectively brittle. If your part sees cold service, this decides the material before any other consideration.

If you are choosing between ABS, PC and PC+ABS rather than specifying ABS itself, that decision has its own guide: PC vs ABS vs PC+ABS →. This page is about specifying and molding ABS once ABS is the answer.

Materials Library — Plastics & Mold Steels on JBRplas

PC Injection Molding: Properties, Grades, Applications and DFM Notes

What PC Is — and What It Is Not

ABS Injection Molding: Properties, Grades, Applications and DFM Notes

What ABS Is — and What It Is Not