# Regrind particle-size control before recompounding

Canonical: https://woodplasticcomposite.net/guides/regrind-particle-size-control-before-recompounding/
Language: en
Updated: 2026-10-15
Version: 1
Review: AI-assisted English editorial draft. Human technical review has not been recorded.

## Summary

Regrind is a manufactured feedstock with its own size distribution and handling behaviour. It should not be described only by the percentage added to a WPC recipe.

## Technical context

Grinding conditions and the source components influence what enters the next process. Fine material and larger fragments may feed differently. A blend containing the same nominal regrind fraction can therefore behave differently between batches.

https://woodplasticcomposite.net/guides/regrind-particle-size-control-before-recompounding/#technical-context

## What to measure and document

Record source identity, grinding method and a suitable particle-size check. Keep contaminants and incompatible product variants out of the approved stream. Compare feeding stability and finished-product results when changing the regrind preparation process.

https://woodplasticcomposite.net/guides/regrind-particle-size-control-before-recompounding/#verification-plan

## Implications for development and specification

Set reuse boundaries through qualification rather than an arbitrary universal percentage. Internal production scrap and recovered outdoor products are different feedstock situations. Traceability should distinguish them so a recycled-content claim does not conceal uncontrolled material history.

https://woodplasticcomposite.net/guides/regrind-particle-size-control-before-recompounding/#practical-decision

## Related reading and evidence limits

A reprocessing study of a specific PVC-based WPC; other matrices require their own evidence. Use the linked work as related reading. The practical checks above are editorial recommendations, not reported test results or a substitute for product qualification.

https://woodplasticcomposite.net/guides/regrind-particle-size-control-before-recompounding/#reading-scope

## Key points

Grinding conditions and the source components influence what enters the next process.
Record source identity, grinding method and a suitable particle-size check.
Set reuse boundaries through qualification rather than an arbitrary universal percentage.

## Comparison

Review step | Evidence to retain
Material and geometry | Exact specimen or product identity
Verification | Method, conditions and individual observations
Decision | Approved scope and documented limitations

## What evidence is needed for regrind particle-size control before recompounding?

Record source identity, grinding method and a suitable particle-size check. Keep contaminants and incompatible product variants out of the approved stream. Compare feeding stability and finished-product results when changing the regrind preparation process.

## Sources

1. Reprocessing PVC-based wood-plastic composites — https://doi.org/10.3390/polym18121509