WPC manufacturing: extrusion, moulding and pultrusion

Match process to product #

Extrusion produces continuous profiles. Injection moulding fills a shaped cavity and suits discrete components. Compression moulding consolidates material within a mould. Pultrusion pulls reinforcement through a forming process and is especially associated with continuous reinforcement; it should not be treated as a synonym for wood-flour extrusion. [R34,R35]

Twin-screw and single-screw equipment can occupy different roles in a production line. The appropriate configuration depends on feeding, mixing, venting, throughput and the material's rheology. Compounding and final shaping can be separate stages or integrated in a selected process.

Treat 200°C as a guideline, not a switch #

The relatively limited thermal tolerance of wood is one reason low-processing-temperature polymers are common. However, a blanket statement that no WPC may ever exceed 200°C is too rigid. Actual degradation depends on exposure and conditions, including residence time.

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An editorial process-control checklist #

Record feedstock moisture, dosing accuracy, temperature profile, melt temperature where measured, output, pressure and rejected product. Distinguish machine settings from actual material conditions. Include start-up and shutdown material in the traceability record.

A shear-thinning melt may flow differently as the process conditions change; the practical task is to establish a stable operating window rather than copying a temperature from another factory. Dimensional checks, appearance and retained mechanical performance should confirm that the chosen settings produce the intended article consistently.

For buyers, process sophistication matters most when it results in repeatable, traceable product quality.

Evidence and source scope #

[1] Research chapter; wood flour and thermal-processing context.

[2] Research review; process context.

[3] University technical-reading index.

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