Multi Cavity Scale Up

Tooling Design

Runner balance and thermal control become highly complex when expanding the number of cavities in a mold. In a successful multi cavity scale up, each flow path must deliver molten plastic to each cavity at the identical temperature and pressure. Balanced hot runner systems are designed to prevent the polymer from cooling unevenly across the mold plate.

If the melt reaches one cavity later than another, the resulting parts will have different weights and dimensions.

Process Calibration

Operating a high volume mold requires a complete recalculation of the injection pressure, hold time, and clamping force used for the prototype. During the multi cavity scale up, the molder must adjust the machine parameters to handle the increased volume of plastic injected per cycle. A press that worked well for a single cavity mold might lack the injection rate or clamping force needed for a sixty-four cavity tool.

Accurate pressure sensors within the mold help ensure each cavity receives the same packing pressure.

Production Yield

Small variations in cavity dimensions or runner flow that were invisible in a single cavity tool can cause high scrap rates in high volume production. When executing a multi cavity scale up, a single malformed gate can cause a persistent defect in one specific cavity, while the others produce perfect parts. Identifying and rectifying these cavity-to-cavity variations requires structured short-shot testing and individual cavity measurements.

Without this systematic analysis, the overall yield will suffer, increasing the cost per part through waste and press downtime.