Meaning
Internal pressure spikes occur during the final moments of the cavity filling stage when the melt reaches the furthest point from the gate. While the average pressure during injection is lower, the injection pressure peak indicates the maximum resistance the machine must overcome to pack the mold completely. This value helps a processor determine if the machine has enough capacity for a specific part.
Filling Sequence
The hydraulic or electric drive pushes the screw forward at a set velocity until the cavity is nearly full. As the mold reaches capacity, the injection pressure peak is recorded just before the machine switches to the holding stage. This transition is essential for preventing part defects.
Tooling Protection
High pressure settings can damage the mold if they exceed the design limits of the steel. Monitoring the injection pressure peak allows a moulder to detect when a gate is freezing off or if the melt temperature has dropped. Such data protects the investment in expensive multi-cavity tools.
Part Uniformity
Shot-to-shot consistency is measured by the stability of these maximum values over hundreds of cycles. A drifting injection pressure peak suggests changes in material viscosity or a failing check ring. Stable values indicate a controlled and repeatable process.
