Should reusable regrind count as good output?

Count regrind as good output only if it is approved and returned to the process within your yield definition.

Can I use part count instead of weight?

Use weight when possible. Part count works only if part weight is stable and input is converted to the same basis.

Should startup purge be included in input?

Yes, include startup purge when measuring total run yield so the result reflects actual material efficiency.

How can I use the result?

Use it to tune processing windows, reduce scrap, update purchase quantities, and improve cost per good part or roll.

Bioplastics & Biomaterials Processing calculator

Biomaterial Yield Calculator

Biomaterial yield shows how much usable output is produced after drying loss, startup scrap, purge, trim, off-spec parts, degraded resin, and quality rejects. Production managers and process engineers use it to understand actual material efficiency for PLA, PHA, PBAT, starch blends, fiber-filled compounds, sheet, film, and molded parts.

What this calculator does

Calculate good biomaterial output as a percentage of total resin, compound, film, sheet, or molded part input, with a target yield for production review.
a processor needs to compare good biomaterial output with total material input for a run, line, shift, or formulation
Returns good output as a percentage of total material charged to the process.

Formula used

Biomaterial yield = good biomaterial output ÷ total biomaterial input × 100
Material yield gap to target = biomaterial yield - target material yield

Inputs explained

Good biomaterial output: Use accepted pellets, sheet, film, molded parts, rolls, or finished packaging weight after quality release.
Total biomaterial input: Use virgin resin, regrind, filler, fiber, additive, masterbatch, and compound weight charged to the process.
Target material yield: Use the expected yield for the resin family, process, gauge, part weight, and startup condition.

How to use the result

Use it for extrusion, compounding, injection molding, film, sheet, thermoforming, and packaging yield reviews.
It is a mass-yield calculation and does not identify whether losses came from moisture, degradation, trim, gauge variation, or rejects.

Common questions

Should reusable regrind count as good output? Count regrind as good output only if it is approved and returned to the process within your yield definition.
Can I use part count instead of weight? Use weight when possible. Part count works only if part weight is stable and input is converted to the same basis.
Should startup purge be included in input? Yes, include startup purge when measuring total run yield so the result reflects actual material efficiency.
How can I use the result? Use it to tune processing windows, reduce scrap, update purchase quantities, and improve cost per good part or roll.

Last reviewed 2026-05-12.