Blow Molding & Hollow Plastic Products worked example

Flash Scrap Rate at 5.04% target maximum flash scrap rate: a worked example

Suppose target maximum flash scrap rate falls to 5.04%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Calculate flash, tail, dome, and trim scrap as a percentage of total blow molding resin input, with a target scrap rate for the process.

The inputs for this scenario

  • Flash and trim scrap weight: 420 units (held at the documented default)
  • Total resin input weight: 5,200 units (held at the documented default)
  • Target maximum flash scrap rate: 5.04 % (the input this scenario stresses; the baseline uses 7)

Working through the calculation

  • The calculation starts from the formula this tool documents: Flash scrap rate = flash and trim scrap weight ÷ total resin input weight × 100.
  • Flash scrap rate works out to 8.08 % flash scrap at these inputs, and this is the headline figure for the scenario.
  • Flash scrap gap to target works out to -3.04 points at these inputs.
  • Flash and trim scrap weight works out to 420 lb or kg at these inputs.
  • Total resin input weight works out to 5,200 lb or kg at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target maximum flash scrap rate sits at 7% and the headline result is 8.08 % flash scrap, this scenario lands almost exactly on the baseline at 8.08 % flash scrap.
  • It divides flash and trim scrap weight by total resin input weight to express scrap as a percentage, then subtracts that rate from your target maximum to show the gap in percentage points. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Flash scrap rate: 8.08 % flash scrap (headline result)
  • Flash scrap gap to target: -3.04 points
  • Flash and trim scrap weight: 420 lb or kg
  • Total resin input weight: 5,200 lb or kg

Run it with your numbers

  • To rerun this with your own numbers, open the live Flash Scrap Rate calculator, set target maximum flash scrap rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.