# Cell-size distribution in foamed WPC

Canonical: https://woodplasticcomposite.net/guides/cell-size-distribution-in-foamed-wpc/
Language: en
Updated: 2026-10-15
Version: 1
Review: AI-assisted English editorial draft. Human technical review has not been recorded.

## Summary

Foamed WPC should be characterised by a cell distribution rather than one attractive microscope image. Local cell structure can vary across a section and along a production run.

## Technical context

An average cell size hides the presence of unusually large voids and differences between skin and core. Image preparation and the selected measurement area can influence the reported distribution, especially in an anisotropic structure.

https://woodplasticcomposite.net/guides/cell-size-distribution-in-foamed-wpc/#technical-context

## What to measure and document

Define the sampling locations, image scale and counting rules before comparing trials. Retain images and report the distribution with density and relevant mechanical results. Distinguish intentionally formed cells from defects where the investigation requires it.

https://woodplasticcomposite.net/guides/cell-size-distribution-in-foamed-wpc/#verification-plan

## Implications for development and specification

Use microscopy to support a process explanation, not to certify the whole product alone. A visually uniform foam still needs application-specific testing. Manufacturing changes should be assessed against the same sampling method to avoid mistaking measurement variation for improvement.

https://woodplasticcomposite.net/guides/cell-size-distribution-in-foamed-wpc/#practical-decision

## Related reading and evidence limits

An experimental PP-composite foaming study using a particular processing arrangement. 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/cell-size-distribution-in-foamed-wpc/#reading-scope

## Key points

An average cell size hides the presence of unusually large voids and differences between skin and core.
Define the sampling locations, image scale and counting rules before comparing trials.
Use microscopy to support a process explanation, not to certify the whole product alone.

## 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 cell-size distribution in foamed WPC?

Define the sampling locations, image scale and counting rules before comparing trials. Retain images and report the distribution with density and relevant mechanical results. Distinguish intentionally formed cells from defects where the investigation requires it.

## Sources

1. Foaming PP-based WPC using a spherical cavity mixer — https://doi.org/10.3390/polym13183179