Injection Molding worked example
Scrap Resin Cost at 3.45% non-recoverable scrap rate: a worked example
Push non-recoverable scrap rate up to 3.45% and the picture changes. This example computes every intermediate figure at that operating point. Use this to quantify material waste costs for lean manufacturing reports, justify quality improvements, or compare scrap costs across molding cells.
The inputs for this scenario
- Annual resin throughput across all presses: 50,000 kg/year (unchanged)
- Non-recoverable (purge, runner, reject) scrap rate: 3.45 % (raised for this scenario; the documented default is 3)
- Delivered resin price: 2.85 $/kg (unchanged)
Working through the calculation
- Applying the documented formula (Annual scrap cost = Resin consumption x (Scrap rate / 100) x Resin cost per kg) to the inputs above produces each figure below.
- At this operating point the engine returns 491,625 $ for result, the number this scenario is built around.
- At this operating point the engine returns 491,625 value for scrap volume x resin cost.
- At this operating point the engine returns 1 x for multiplier.
- At this operating point the engine returns 172,500 value for factor a x b.
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 15% above the baseline at 491,625 $.
- It computes the annual dollar cost of non-recoverable resin scrap from your throughput, scrap rate, and delivered resin price. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.
Results at a glance
- Result: 491,625 $ (headline result)
- Scrap volume x Resin cost: 491,625 value
- Multiplier: 1 x
- Factor A x B: 172,500 value
Run it with your numbers
- Every input above is editable in the live Scrap Resin Cost calculator, which recalculates instantly and can be shared with the inputs intact.
Last reviewed 2026-05-12.