Compression Molding Defects and Troubleshooting
Common issues: scorching, porosity, flash, short fill.
Defect Categories
Scorch: material starts curing before mold closes. Pre-heat temp or material flow too slow. Porosity: entrapped air or moisture. Vacuum assistance helps. Flash variation: uneven clamping force or material charge. Sticking: mold release insufficient. Warpage: cure gradient across thickness. Sink marks: thick sections cure last without packing pressure.
| Defect | Cause | Fix |
|---|---|---|
| Scorch | Preheat too hot | Reduce preheat 10-15C, increase closing speed |
| Porosity | Air trapped | Add vacuum vents, degas mold at 50% close |
| Sink marks | Thick section | Pre-form charge shape to match, increase pressure |
| Blister | Moisture | Pre-dry material 2h at 70-90C |