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Five Steps To Reduce The Dimensional Shrinkage of PC GF10

Views: 0 Author: XINYITE PLASTIC Publish Time: 2025-08-20 Origin: Site

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Five-step process recipe to further reduce the dimensional shrinkage of PC-GF10 (10 % glass-fiber reinforced polycarbonate) to < 0.3 % while minimizing warpage.

1. Verify the "reducible window"

PC GF10 1

PC GF10 2

2. Immediate process tweaks (no material change)

• Mold temperature: 100–120 °C (up from 80 °C) → shrinkage ↓ 0.03–0.05 %
• Packing pressure: 100–130 MPa (up from 80 MPa) → shrinkage ↓ ~0.03 %
• Packing time: +20–30 % to avoid gate seal-off

• Cooling time: ≥12 s (tripling baseline) → shrinkage ↓ 40 % in trials

3. Gate & orientation optimization

• Multi-point valve gates reduce MD/TD shrinkage difference to < 0.02 %

• Gate thickness = 0.7 × wall thickness to prevent shear overheating

4. Annealing (post-mold)

• 110 °C × 2h releases frozen-in stresses → secondary shrinkage < 0.02 %

• Improves flatness by ~30 %, ideal for precision housings

5. Micro-modification if still out of spec

• 2 % organo-montmorillonite (OMMT) → additional shrinkage ↓ 0.02–0.03 %, impact loss < 5 %
• 5 % PC/ABS blend → shrinkage ↓ 0.02 % with retained impact strength

Quick validation loop

1. Mold at 110 °C, pack 120 MPa, cool 12 s → measure 5 parts

2. If > 0.35 %, anneal 110 °C × 2 h → re-measure

3. If still high, re-compound with 2 % OMMT and re-run

Following these five steps stabilizes PC-GF10 shrinkage at 0.25–0.30 %, meeting the tight dimensional tolerances required for precision electronic housings, optical brackets, and automotive structural parts.