OnForce™ Long Glass Fiber Reinforced Thermoplastics: developed for automotive foot pedals, providing high dimensional stability, rigidity and flexibility, cyclic fatigue strength, and long-term creep resistance as well as excellent chemical and UV resistance, shows good colorability (including silver) and ease of processing

SILVER MIST

Surface Defects Silver streaking or splay marks

Surface Defects Silver streaking or splay marks

DEFECTS Design Guide 37 SOURCES Mold Machine Material Process Hot spots Improper cooling Venting plugged Leaking check ring Barrel too hot Contamination Too hot No cushion Hold pressure too low Melt temperature too high Reduced transfer position Back pressure too low RECOMMENDED ADJUSTMENTS Check venting Add a flow leader Insure cushion position Insure proper screw recovery Add a foaming agent Increase hold pressure Increase hold time Reduce injection speed Reduce melt temperature Reduce mold temperature Increase mold temperature Sink Root cause: Material is shrinking away from mold surface. 38 Gravi-Tech SOURCES Mold Machine Material Process Venting impaired Condensation Heater band overriding Wrong screw configuration Wet material Contamination Injection speed too fast Residence time too long Excessive decompression RECOMMENDED ADJUSTMENTS Increase gate size Check mold surface for condensation Check for condensation in feed throat Check dry material dew point Dry material Increase mold temperature Reduce melt temperature Reduce back pressure Reduce screw speed Reduce decompression Splay • Silver streaks on part Root cause: Material degradation DEFECTS Design Guide 39 SOURCES Mold Machine Material Process Venting impaired Leaking check ring Heating band burned out New lot Contamination Melt temperature too low Hold pressure too low Back pressure too low Transfer position too high Injection speed too low RECOMMENDED ADJUSTMENTS Clean mold surface Check vents Increase gate size Increase melt temperature Increase mold temperature Increase hold pressure Increase hold time Increase injection speed Increase back pressure Decrease transfer Surface Finish Root cause: Material is not reproducing the mold surface finish. 40 Gravi-Tech SOURCES Mold Machine Material Process Tooling damage Heater band overriding Leaking check ring Contamination Wet material Melt temperature too high Back pressure too high No cushion Pack pressure too high Hold time too low RECOMMENDED ADJUSTMENTS Reduce gate size Increase cooling in gate area Check gate for blockage Check thermocouples for continuity Ensure cushion is maintained Dry material Reduce melt temperature Increase hold pressure Increase hold time Reduce back pressure Increase cooling time Reduce tip temperature Gate Vestige Root cause: Material doesn’t have a clean break at gate.

DEFECTS Design Guide 37 SOURCES Mold Machine Material Process Hot spots Improper cooling Venting plugged Leaking check ring Barrel too hot Contamination Too hot No cushion Hold pressure too low Melt temperature too high Reduced transfer position Back pressure too low RECOMMENDED ADJUSTMENTS Check venting Add a flow leader Insure cushion position Insure proper screw recov- ery Add a foaming agent Increase hold pressure Increase hold time Reduce injection speed Reduce melt temperature Reduce mold temperature Increase mold temperature Sink Root cause: Material is shrinking away from mold surface. 38 Gravi-Tech SOURCES Mold Machine Material Process Venting impaired Condensation Heater band overriding Wrong screw configuration Wet material Contamination Injection speed too fast Residence time too long Excessive decompression RECOMMENDED ADJUSTMENTS Increase gate size Check mold surface for condensation Check for condensation in feed throat Check dry material dew point Dry material Increase mold temperature Reduce melt temperature Reduce back pressure Reduce screw speed Reduce decompression Splay • Silver streaks on part Root cause: Material degradation DEFECTS Design Guide 39 SOURCES Mold Machine Material Process Venting impaired Leaking check ring Heating band burned out New lot Contamination Melt temperature too low Hold pressure too low Back pressure too low Transfer position too high Injection speed too low RECOMMENDED ADJUSTMENTS Clean mold surface Check vents Increase gate size Increase melt temperature Increase mold temperature Increase hold pressure Increase hold time Increase injection speed Increase back pressure Decrease transfer Surface Finish Root cause: Material is not reproducing the mold surface finish. 40 Gravi-Tech SOURCES Mold Machine Material Process Tooling damage Heater band overriding Leaking check ring Contamination Wet material Melt temperature too high Back pressure too high No cushion Pack pressure too high Hold time too low RECOMMENDED ADJUSTMENTS Reduce gate size Increase cooling in gate area Check gate for blockage Check thermocouples for continuity Ensure cushion is maintained Dry material Reduce melt temperature Increase hold pressure Increase hold time Reduce back pressure Increase cooling time Reduce tip temperature Gate Vestige Root cause: Material doesn’t have a clean break at gate.

Metallic fibers that create electrical conductivity include copper, silver and stainless steel. When molding an electrically conductive compound, create a silver or fibrous surface, not a resin-rich surface, and use a low extruder barrel temperature.1 For electrically nonconductive but thermally conductive compounds, raise the barrel temperature.2

Metallic fibers that create electrical conductivity include copper, silver and stainless steel. When molding an electrically conductive compound, create a silver or fibrous surface, not a resin-rich surface, and use a low extruder barrel temperature.1 For electrically nonconductive but thermally conductive compounds, raise the barrel temperature.2

Metallic fibers that create electrical conductivity include copper, silver and stainless steel. When molding an electrically conductive compound, create a silver or fibrous surface, not a resin-rich surface, and use a low extruder barrel temperature.1 For electrically nonconductive but thermally conductive compounds, raise the barrel temperature.2

Metallic fibers that create electrical conductivity include copper, silver and stainless steel. When molding an electrically conductive compound, create a silver or fibrous surface, not a resin-rich surface, and use a low extruder barrel temperature.1 For electrically nonconductive but thermally conductive compounds, raise the barrel temperature.2