Second Source Tooling Priced before the First Tool Wears Out
Pricing secondary tooling during initial contract negotiation locks steel costs and machining rates before primary tool wear destroys commercial leverage.
Screw Recovery
Meaning
Plasticising stages of the moulding cycle involve the rotation of the screw to melt resin and accumulate the next shot of molten polymer. The screw recovery phase occurs during the cooling time of the part when the clamp is closed. This timing ensures that the material is fully prepared for the next injection phase without extending the cycle time.
Process Mechanics
Rotation of the screw draws resin granules from the feed throat and moves them forward through the heating zones. Proper screw recovery relies on balanced backpressure to ensure uniform melting and to prevent the entrapment of air bubbles in the melt. Poor settings lead to inconsistent shot volumes.
Thermal Homogeneity
Friction and heat from the heaters melt the resin as the screw rotates. Fast screw recovery speeds can raise the melt temperature through shear, causing polymer degradation. Slow rotation speeds ensure gentle mixing but can extend cycle time.
Cycle Optimization
Optimization of the screw speed and backpressure keeps the recovery time slightly shorter than the part cooling time. If screw recovery takes longer than the cooling phase, the moulding cycle is delayed, which raises the hourly operating cost of the press. Proper alignment of these phases maximizes the production throughput of the factory and prevents the melt from sitting too long in the hot barrel.