Outdoor garden decking
Hollow or solid decking profiles for patios, pools and landscaping.
WPC EXTRUSION
How WPC Decking & Board Is Made
From wood flour and recycled PE to outdoor composite decking.
WPC combines wood flour or rice husk with PE or PP so the finished board looks like timber but resists rot, splintering and repeated painting. The hardest part is not the profile shape — it is moisture control and material bonding.
What WPC products are used for
Typical WPC formulation contains 50-70% wood flour or rice husk, PE/PP matrix, coupling agent, UV stabiliser, lubricant and pigment. The product is popular because recycled PE can be used while giving a wood-like outdoor surface.
Balcony flooring
Weather-resistant boards for terrace and residential flooring.
Exterior wall cladding
Long profiles with colour stability and textured surface.
Garden furniture panels
Composite boards for benches, doors and outdoor furniture.
Raw material: wood flour, PE/PP and coupling agent
Moisture is the main enemy of WPC extrusion. Wood flour must be dried below about 2% moisture; otherwise steam bubbles form inside the profile and cause severe surface defects. The plastic matrix is usually PE or PP, often with recycled content. A coupling agent such as MAPE, maleic anhydride grafted PE, chemically bonds wood flour to the PE matrix. Without it, wood and plastic separate under load and the board loses strength.
- Typical MAPE loading is 2-4 phr depending on wood flour content and target strength.
- Two-step production compounds pellets first, then extrudes profile; one-step feeds raw materials directly but needs tighter formulation control.
- Lubricant and UV stabiliser are required for surface quality and outdoor durability.
Production process
WPC production uses lower processing temperatures than PE pipe because wood flour can burn and discolor. Conical twin-screw extrusion is common because the material is abrasive and needs strong mixing at controlled screw speed.
Wood flour drying
Wood flour or rice husk is dried in a silo or flash dryer to below 2% moisture. Wet filler creates steam, voids and rough surface.
Mixing
Wood flour, PE/PP, coupling agent, lubricant, pigment and stabiliser are mixed. Correct dosing decides board strength and surface finish.
Conical twin-screw extrusion
A conical counter-rotating twin screw gives strong mixing with lower discharge speed, reducing screw wear from abrasive wood flour.
WPC profile die
The die forms hollow or solid decking sections, often 140x25mm or 150x25mm. Hollow cores reduce weight, material cost and warping.
Vacuum calibration
Calibration blocks hold the profile size while cooling begins. WPC cools slowly because wood flour adds thermal mass.
Cooling and haul-off
Cooling length is often 6-10m. Haul-off must avoid surface marks while keeping the board straight.
Saw cutting and surface treatment
Boards are cut to length, then brushed or embossed. Wire brushing raises a wood-grain texture; embossing improves slip resistance and appearance.
Finished WPC board requirements
Finished WPC decking is checked for board width, thickness, density, straightness, surface texture, colour consistency, water absorption and flexural strength. Outdoor products also require UV stability and slip resistance. Because customers see and walk on the surface, brushing depth, embossing pattern and colour matching are commercial as well as technical requirements.
Machines required
These are the core machines for a WPC decking or board line. The configuration changes depending on one-step or two-step processing and whether co-extrusion cap layer is required.
Conical Twin Screw Extruder
Mixes wood flour and PE/PP at controlled shear and temperature.
WPC Profile Die
Forms hollow decking or board profiles.
Vacuum Calibration Table
Controls board size and straightness during cooling.
Cooling & Haul-off System
Removes heat slowly and pulls the profile without marking.
Brushing & Embossing Unit
Creates wood-grain texture and anti-slip surface.
Technical reference
Planning reference only. Final configuration depends on your target spec — share it with the engineering team for a matched proposal.
| Output rate | 100-600 kg/h |
|---|---|
| Wood flour content | 50-70% |
| Board width | 90-200mm |
| Thickness | 18-40mm |
| Processing temperature | 160-180°C |
| Material | Wood flour / rice husk + PE or PP |
Ready to produce WPC decking and board?
Send your board section, wood flour ratio, surface finish, output target and one-step or two-step preference. We will configure drying, extrusion, calibration and finishing equipment.
Get my technical proposal