Injection Molding worked example

Scrap Resin Cost at 2.16% non-recoverable scrap rate: a worked example

Suppose non-recoverable scrap rate falls to 2.16%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Calculate the annual cost of scrapped resin from rejects, purging, startup waste, and non-recoverable material.

The inputs for this scenario

  • Annual resin throughput across all presses: 50,000 kg/year (held at the documented default)
  • Non-recoverable (purge, runner, reject) scrap rate: 2.16 % (the input this scenario stresses; the baseline uses 3)
  • Delivered resin price: 2.85 $/kg (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Annual scrap cost = Resin consumption x (Scrap rate / 100) x Resin cost per kg.
  • Result works out to 307,800 $ at these inputs, and this is the headline figure for the scenario.
  • Scrap volume x Resin cost works out to 307,800 value at these inputs.
  • Multiplier works out to 1 x at these inputs.
  • Factor A x B works out to 108,000 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where non-recoverable scrap rate sits at 3% and the headline result is 427,500 $, this scenario comes in 28% below the baseline at 307,800 $.
  • It computes the annual dollar cost of non-recoverable resin scrap from your throughput, scrap rate, and delivered resin price. 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

  • Result: 307,800 $ (headline result)
  • Scrap volume x Resin cost: 307,800 value
  • Multiplier: 1 x
  • Factor A x B: 108,000 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Scrap Resin Cost calculator, set non-recoverable scrap rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.