Modified Engineering Plastics Explained: A Property Map and Selection Logic for Five Common Systems

Start with three tables: heat, cost, moulding difficulty

Heat: PP roughly 100-130 °C compounded, ABS 85-100 °C, PC/ABS 95-115 °C, PC 125-135 °C, PA6 190-210 °C glass reinforced, PPS around 260 °C. Heat resistance is almost always the first filter.

Cost: PP lowest, then ABS, PA and PC comparable and higher, PC/ABS between PC and ABS, PPS highest. Moulding difficulty broadly inverts flow: PP easiest, PA next but needs drying, PC needs high melt temperature and mould temperature, PPS requires moulds above 140 °C.

Work backwards from the application

Cosmetic plus low cost → ABS or PP-TD20. Drop-resistant plus moderate heat → PC/ABS. High-temperature structural → PA6-GF or PA66-GF. Transparent or high impact plus weathering → PC. Above 260 °C plus chemical resistance → PPS.

When requirements overlap there are usually two or three candidates; ranking by total piece cost — material plus cycle time plus yield plus post-processing — is more useful than comparing data sheets.

Why early involvement pays

Compound formulations are adjustable. Within a single PP-TD20 grade, filler loading and toughener ratio can be tuned within roughly ±15% to favour one property. Doing that during development costs almost nothing; doing it after the tool is cut means re-cutting and re-testing.

The most effective way to work is to hand over the complete duty cycle up front: temperature, load, media, service life, appearance class and certification.