Injection Molding worked example

Plastic Regrind Savings with annual regrind used in production of 7,500 kg/year: a worked example

Suppose annual regrind used in production falls to 7,500 kg/year. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate annual material cost savings from using regrind instead of 100% virgin resin in injection molding production.

The inputs for this scenario

  • Annual regrind used in production: 7,500 kg/year (the input this scenario stresses; the baseline uses 15,000)
  • Savings per kg (virgin price minus regrind cost): 1.2 $/kg (held at the documented default)
  • Quality/yield derating factor: 0.95 x (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Annual savings = Regrind consumption x Cost savings per kg x Quality factor.
  • Result works out to 8,550 $ at these inputs, and this is the headline figure for the scenario.
  • Gross savings (volume x cost difference) works out to 8,550 value at these inputs.
  • Multiplier works out to 1 x at these inputs.
  • Factor A x B works out to 9,000 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where annual regrind used in production sits at 15,000 kg/year and the headline result is 17,100 $, this scenario comes in 50% below the baseline at 8,550 $.
  • It computes annual savings as regrind volume multiplied by the per-kg cost difference, then derated by a quality/yield factor. 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: 8,550 $ (headline result)
  • Gross savings (volume x cost difference): 8,550 value
  • Multiplier: 1 x
  • Factor A x B: 9,000 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Plastic Regrind Savings calculator, set annual regrind used in production to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.