The Lab

Molding tools that actually run

Free calculators for the studies that set up a molding process, in the order they are run — each one fixes a setpoint the next one holds constant. Enter your own numbers: nothing you enter is sent to us unless you choose to contribute a study or attach it to a quote request, and recent studies are kept only in your own browser so you can pick them up again.

  1. Step 01Viscosity curveFixes the injection velocity every later study runs at.
  2. Step 02Cavity balanceFixes whether the cavities fill alike, and whether the tool or the process is to blame.
  3. Step 03Pressure dropFixes where pressure is consumed, and how much headroom is left for pack.
  4. Step 04Cosmetic windowFixes the pack pressure and melt temperature setpoints, at the centre of what passes.
  5. Step 05Gate sealFixes the hold time, and the target part weight for production monitoring.
  6. Step 06Cooling timeFixes the cooling time, and with it most of the cycle.
  7. QualityGage R&R StudyRepeatability, reproducibility and %GRR from a parts × operators study.
  8. QualityCpk CalculatorCp, Cpk, and a capability verdict from your measurements.
  9. DesignShrinkage CalculatorCavity dimension from part dimension, and back again.
  10. ProcessClamp Force CalculatorPress tonnage from projected area and cavity pressure.
Three calculations changed in September 2026

Lab studies recompute from your data every time a link is opened, rather than storing an answer — so a study you shared earlier now shows the corrected result. Three methods changed:

  • Gate seal is now the first of three consecutive weights within 0.1% of each other, which is the criterion the study procedure on that page always described. It was previously the first single step under 0.5%, which tended to report seal earlier than it happens.
  • Viscosity curve takes the optimal velocity from the middle of the shear-thinning plateau rather than the flattest single step, which could land on the edge of the range tested.
  • Process capability reports Cpk from within-subgroup sigma and Ppk from overall sigma, labelled separately. The single figure shown before was the overall one, which is Ppk — the number a customer’s SPC package computes. It now also puts a 95% confidence interval on every index, accepts rational subgroups, and withholds its verdict when the measurements are badly non-normal (Anderson–Darling p below 0.01), since every index assumes a normal distribution.

Background reading

  • Materials

    PEEK, Ultem, LCP and COC molded; titanium and stainless machined — and what each does at micro scale.

  • The Comparator

    Asks whether the tolerance you need is one anybody can hold.