# Gravimetric feeder checks for WPC production

Canonical: https://woodplasticcomposite.net/guides/gravimetric-feeder-checks-for-wpc-production/
Language: en
Updated: 2026-10-15
Version: 1
Review: AI-assisted English editorial draft. Human technical review has not been recorded.

## Summary

Feeder accuracy affects whether the intended WPC recipe reaches the machine consistently. Calibration should address the material and operating conditions, not only an empty equipment display.

## Technical context

A loss-in-weight feeder estimates delivery from changing measured mass. Refill cycles, vibration and material flow can complicate interpretation. A stable total output does not prove that each individual ingredient is being delivered at the intended rate.

https://woodplasticcomposite.net/guides/gravimetric-feeder-checks-for-wpc-production/#technical-context

## What to measure and document

Use the equipment maker's approved verification procedure and suitable independent mass checks. Record feeder setpoint, actual delivery, refill behaviour and the relevant material lot. Compare short disturbances with the time window used for collecting test specimens.

https://woodplasticcomposite.net/guides/gravimetric-feeder-checks-for-wpc-production/#verification-plan

## Implications for development and specification

Keep feeder maintenance and calibration evidence with batch records. If the formula is correct on paper but properties drift, examine delivery consistency before reformulating. No adjustment should bypass guards or interlocks on operating production equipment.

https://woodplasticcomposite.net/guides/gravimetric-feeder-checks-for-wpc-production/#practical-decision

## Related reading and evidence limits

Official guidance on controlling measurement processes and supporting uncertainty statements. 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/gravimetric-feeder-checks-for-wpc-production/#reading-scope

## Key points

A loss-in-weight feeder estimates delivery from changing measured mass.
Use the equipment maker's approved verification procedure and suitable independent mass checks.
Keep feeder maintenance and calibration evidence with batch records.

## 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 gravimetric feeder checks for WPC production?

Use the equipment maker's approved verification procedure and suitable independent mass checks. Record feeder setpoint, actual delivery, refill behaviour and the relevant material lot. Compare short disturbances with the time window used for collecting test specimens.

## Sources

1. NIST: statistical control of measurement processes — https://www.itl.nist.gov/div898/handbook/mpc/section2/mpc2.htm