Blow Molding & Hollow Plastic Products worked example

Flash Scrap Rate at 8.05% target maximum flash scrap rate: a worked example

This scenario runs the flash scrap rate calculation on the strong side: 8.05% target maximum flash scrap rate, with every other input held at its documented default. a blow molding line needs to track flash and trim scrap against total resin consumed for a run or shift

The inputs for this scenario

  • Flash and trim scrap weight: 420 units (unchanged)
  • Total resin input weight: 5,200 units (unchanged)
  • Target maximum flash scrap rate: 8.05 % (raised for this scenario; the documented default is 7)

Working through the calculation

  • Applying the documented formula (Flash scrap rate = flash and trim scrap weight ÷ total resin input weight × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 8.08 % flash scrap for flash scrap rate, the number this scenario is built around.
  • At this operating point the engine returns -0.03 points for flash scrap gap to target.
  • At this operating point the engine returns 420 lb or kg for flash and trim scrap weight.
  • At this operating point the engine returns 5,200 lb or kg for total resin input weight.

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.
  • Use it at the end of a run or shift to grade scrap performance, or during troubleshooting when you suspect pinch-off wear or parison programming is driving excess moil. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • Flash scrap rate: 8.08 % flash scrap (headline result)
  • Flash scrap gap to target: -0.03 points
  • Flash and trim scrap weight: 420 lb or kg
  • Total resin input weight: 5,200 lb or kg

Run it with your numbers

  • Every input above is editable in the live Flash Scrap Rate calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.