Regrind and recovered material: the only line that subtracts

Nearly every line on a cost sheet adds. Recovered material is the exception: it is the one number that comes off the total, which is precisely why it needs care. Lines that reduce a cost get less scrutiny than lines that increase it.

What is genuinely recoverable

Thermoplastic runners, sprues and rejected parts can be granulated and molded again. That makes this trade different from most: in sheet metal the offcut is sold, here it goes back into the hopper.

But recovery is not free and not unlimited:

• Granulating costs power and labor, and the granulator is capital that has to be paid for.
• Material degrades on reprocessing, so most specifications cap the proportion of regrind allowed.
• Colored or contaminated material may not go back into the same part, only into something less demanding.

The double subtraction

The error, and it always makes the part look cheaper:

• Costing material as **part weight only**, quietly assuming the runner was free — and then
• also entering a recovery credit for the runner.

The runner has now been subtracted twice. Charge the full shot weight, then credit the recovery. One or the other, never both halves of the same saving.

This is the same shape of error as the skeleton in sheet metal, and it appears in every industry where a byproduct has value. Worth recognizing as a pattern rather than as a plastics quirk.

When the answer is zero, say zero

Thermoset materials cannot be reprocessed. Medical and food-contact parts often forbid regrind. Some customers forbid it contractually.

In all those cases the recovery value is zero — and **enter zero rather than leaving the field blank**. Zero says you considered it and the answer is none; blank says nobody knows. A reader comparing your sheet with another cannot tell those apart unless you make it explicit.

Where this line actually improves

1. Reduce runner weight — hot runner systems and better gating remove the material rather than recovering it, which is always worth more than recovering it well.
2. Keep regrind streams separated by color and grade, so more of it substitutes for virgin material instead of dropping to low-grade use.
3. Reduce startup scrap, which is regrind you paid to make and paid again to reprocess.