Gate-seal setup
Step hold time while keeping pack pressure, transfer, temperatures and total cycle treatment controlled. Weigh parts after the same interval. A sustained weight plateau is a cue to inspect dimensions, sink and cavity-pressure evidence—not a standalone pass.
Pressure-drop setup
Record cumulative plastic pressure for a nozzle air shot, through sprue/runner, through gate and a fill-only part. Subtract adjacent cumulative readings to localize measured increments. Follow machine, mold and site safety procedures; do not perform an air shot if local procedures prohibit it.
Comparison discipline
Repeat at the same material, melt temperature and injection-rate basis. A larger increment supports inspection of that section but does not by itself justify enlarging a runner, gate or nozzle.
Related tools
Process Validation & Stability hub · Relative Viscosity Curve Calculator · Cavity Weight Balance Calculator · Gate Seal Study Analyzer · Pressure Drop Study Calculator · Shot Weight Repeatability Calculator
Sources
PlasticsToday: Scientific Molding, Part 1 · M. Holland: Monitoring Pressure Loss · BASF: Injection-Molding Problems · NIST: Measures of Scale · NIST: Coefficient of Variation · PMC: Filling Imbalance in Multi-cavity Molds · Hingtung: Cavity Balance Study
