Why is material choice part of the design and not a separate step?

The material determines shrinkage, strength, wall thickness, and cycle time, and thus the entire mold around it. A material switch after the design is finalized can affect wall thickness, draft, and even mold construction. That's why we select the material as part of the DfM review, not separately.

Which plastics does QDP use most?

The most used engineering plastics are ABS, PP, PA (nylon, also glass fiber reinforced), PC, POM, and TPE, supplemented with biobased grades such as PHA and PLA and recycled variants. Which is best depends on strength, temperature, chemical resistance, and aesthetics.

Can QDP also process biobased or recycled material?

Yes. For biobased and biodegradable materials, we work with PHA and PLA, among others, and for recycled content with PC/ABS blends. Material cost is often the deciding factor for biobased, so we discuss this early in the process.

Design for Manufacturing / Material Selection

DfM deep dive

Material selection: part of the design, not separate from it

The material determines shrinkage, strength, wall thickness and cycle time, and thus the entire mold around it. Unlike a geometric form rule, material selection is a matter of trade-off: mechanical requirements, temperature, chemical resistance, aesthetics and cost all play a role. That’s why we choose the material as part of the design process, not as a separate step afterwards.

A material change leaves its mark on the mold build-up: every material shrinks and flows differently, so wall thickness and draft that are right for one material may be just wrong for another.

Properties listed

Reference values for standard, unfilled grades. For a final choice, we always consult the supplier's datasheet of the specific grade.

Material	Density (g/cm³)	Tensile strength (MPa)	E-modulus (MPa)	HDT @1.8 MPa (°C)	Shrinkage (%)
ABS	1,04-1,06	40-45	2000-2500	75-90	0,4-0,7
ASA	1,06-1,08	40-50	2300-2600	85-95	0,4-0,7
PLA (biobased)	1,24	50-60	3000-3500	50-60	0,3-0,5
HDPE	0,94-0,96	22-30	1000-1400	45-50	1,5-3,0
PA6 (dry)	1,12-1,14	70-85	2700-3000	55-70	0,8-1,5
PA6 GF30	1,35-1,37	170-185	8500-9500	200-215	0,3-0,6
PC	1,20	60-70	2300-2400	125-135	0,5-0,7
PC/ABS	1,10-1,15	50-60	2300-2600	110-125	0,5-0,8
PHA (biobased)	1,20-1,25	20-40	1000-3500	60-120	1,0-2,0
POM	1,41	60-70	2800-3100	100-110	1,8-2,5
PP	0,90-0,91	30-38	1300-1800	50-60	1,2-2,5
TPE	0,90-1,20	5-25	elastomer	n/a	1,0-3,0
TPU	1,10-1,22	25-55	elastomer	n/a	0,8-1,5

Click on a material for properties, applications and mechanical values in detail.

Biobased and recycled as full-fledged routes

Two routes lead to a more sustainable end product: biobased plus biodegradable, or recycled content. For biobased we work with, among others, PHA (100 percent biobased, marine and compost biodegradable, TÜV- and EFSA-certified) and PLA. For recycled content, we use PC/ABS blends with a good balance between impact resistance and chemical resistance.

For biobased materials, the material price is usually the determining factor, not the technique. We map this out early in the process, so that material selection remains a conscious consideration and not a surprise afterwards.

Material selection directly steers wall thickness: see the full DfM pillar or go to wall thickness.

What does this mean for your design?

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