ABS is the resin most rigid consumer housings are made of, and it holds that position because it is unusually easy to get right. It moulds at moderate temperatures and pressures, has low and predictable shrinkage, takes texture and paint well, glues and welds readily, and produces a rigid, tough part without needing a filler.
What it is and why it behaves so well
ABS is a terpolymer, and the three components contribute rigidity, chemical resistance and impact toughness respectively. Grades vary the balance, so a high impact grade and a high heat grade are genuinely different materials wearing the same name. Shrinkage is low and largely uniform, which is why ABS parts hold dimensions better than semi crystalline resins of similar cost.
Processing notes
It must be dried before moulding: moisture in the pellets produces splay and silver streaking that no process adjustment fixes. It moulds over a wide window, which is what makes it forgiving. It textures beautifully, and it takes paint and plating better than almost any other commodity resin, which is why chrome plated ABS exists at all.
Blends and where they help
ABS is frequently blended with polycarbonate to raise impact strength and heat resistance while retaining much of ABS's mouldability and finish. Automotive interiors and electronics housings use these blends heavily. Flame retardant grades exist where a regulatory requirement demands them, and they mould and finish differently enough to need their own trial.
The two limits
Ultraviolet light degrades and yellows unmodified ABS, so outdoor parts need a stabilised grade, a coating or a different resin. And its heat resistance is modest, so anything near a heat source or subject to a hot car interior needs a heat resistant grade or a polycarbonate blend. Both catch people out because ABS is otherwise so accommodating.
Questions people ask about abs injection molding
Why is ABS used for housings?
Because it is rigid, tough, dimensionally stable, easy to mould, and takes texture, paint and plating better than most commodity resins.
Does ABS need drying before moulding?
Yes. Moisture produces splay and silver streaks that cannot be tuned out at the machine, so drying is part of the process rather than a precaution.
Is ABS suitable outdoors?
Not unmodified. Ultraviolet light yellows and embrittles it, so outdoor parts need a stabilised grade, a protective coating or a different resin.
What does blending with polycarbonate do?
Raises impact strength and heat resistance while keeping much of the mouldability and finish quality, which is why the blends dominate automotive interiors.