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Long Fiber Compounds Molding Guidelines
- Full round runners with a diameter of 0.25 in (5.56 mm) are preferred
- Runners should have no sharp corners
- Minimum gate thickness of 0.080 in (2 mm)
- Sprues as short as possible, with initial diameter of 0.25 in (5.56 mm), tapered to 11/32 in (8.73 mm)
- Open channel type hot runner systems are acceptable
- Use same materials for molds as for other reinforced materials
- Feed throat from hopper to machine must have sufficient opening to prevent bridging of long pellet composition
- Reverse barrel profile to 'pre-soak' or 'soften fibers'
- Minimum back pressure should be used, typically 25-50 psi (0.17-0.34 MPa)
Refer to the Processing Conditions section of this website for recommended starting temperatures. Normally, reinforced materials require higher mold temperatures than non-reinforced materials. This helps achieve a smoother, more blemish free surface by providing a resin rich skin on the molded part.