Process Guide: to the manufacture of European Flax and Hemp composites

Drafted by the Alliance’s extended European Scientific Council, this document provides hands-on support for manufacturers and researchers seeking to incorporate European flax and hemp into composite applications. The guide is designed as a technical entry point for professionals looking to initiate, secure or structure projects involving flax and hemp based composites.

It is primarily intended for composite material manufacturers and laboratories that are not yet fully familiar with the properties of these natural fibres. It may also be of interest to more experienced manufacturers, helping them avoid common pitfalls and challenge certain misconceptions regarding the technical viability of flax and hemp.

The use of these fibres requires careful control of several interdependent parameters: temperature, pressure, processing time and moisture content. Excessive heat may degrade the fibres, while high moisture levels can lead to defects in the finished material. Pressure, along with resin flow behaviour, is also critical. In addition, straightforward precautions can significantly improve the quality of manufactured parts: appropriate storage, properly protected surfaces and well-executed finishing operations.

This first section (“Processing Windows”) establishes practical reference points. It is neither an exhaustive scientific review nor a comprehensive engineering manual, but rather a pragmatic document intended to support initial implementation - helping users understand key steps, technical sensitivities and operational limits in order to inform decision-making.