A Complete Guide to Maintenance of WPC Wood Plastic Door Extrusion Equipment

Extrusion Equipment

Maintenance of WPC door extrusion equipment requires careful consideration of both material properties and equipment maintenance. Wood-plastic materials (composite materials of wood flour/plant fiber and plastic) are highly abrasive, easily absorb moisture, and are electrostatically sensitive. This places special demands on extrusion equipment components such as the screw and die. Routine maintenance emphasizes screw anti-wear treatment (such as tungsten carbide overlay), moisture-proofing of wood flour (equipped with a dehumidification and drying system), and electrostatic protection measures (grounding resistance ≤ 2Ω). Furthermore, WPC materials are prone to mold sticking, necessitating regular polishing of the die flow channel (surface roughness Ra ≤ 0.4μm). These characteristics necessitate more frequent and meticulous maintenance, such as daily inspection of the melt pressure sensor (error ≤ 1%FS) and cleaning of the magnetic separator to prevent metal impurities from damaging the screw. Furthermore, maintenance of the two-stage exhaust system (vacuum ≥ -0.08MPa) and traction synchronization calibration (speed ratio deviation ≤ 0.5%) are crucial during continuous production. For daily maintenance of WPC wood-plastic door extrusion equipment, the following key operations must be strictly followed to ensure stable operation:

1. Daily Inspection:

1. Melt Pressure Sensor Calibration: Ensure an error of ≤1% FS to avoid pressure fluctuations that affect product quality.

2. Wood Powder Feed System Cleaning: Clean the magnetic separator every 4 hours to prevent metal impurities from entering the screw and causing wear.

3. Exhaust System Maintenance: Check the vacuum pump filter to ensure a vacuum level ≥ -0.08 MPa to prevent wood powder clogging and poor exhaust.

2. Die and Screw Maintenance:

1. Die Flow Channel Polishing: Use diamond abrasive paste to maintain a surface roughness Ra ≤ 0.4 μm to reduce sticking of the wood-plastic material.

2. Screw Carbon Deposits Cleaning: Use a dedicated wood-plastic cleaning compound (including glass fiber reinforcement) for cyclic cleaning to prevent chemical corrosion.
   

3. Traction System Calibration:

1. Check the traction speed ratio every 8 hours. The deviation must be controlled to ≤ 0.5% to ensure door panel dimensional accuracy.

2. Check the surface cleanliness of the rubber rollers and use a non-silicone cleaner to prevent traction slippage.

4. Moisture and Static Electricity Management:

1. Maintain a stable hopper heating temperature of 80–100°C and a dew point ≤ -40°C to prevent moisture absorption by the wood powder, which can affect extrusion stability.

2. The grounding resistance of all metal components must be ≤ 2Ω to avoid the risk of static electricity accumulation and dust explosions.

5. Lubrication and Cooling System:

1. Regularly add grease to bearings and universal joints, and replace the gear oil in the reduction gearbox every 2,000 hours (4,000 hours for standard equipment).

2. The cooling water temperature must be maintained below 8°C, and scale must be regularly cleaned to prevent pipe blockage.

These measures can effectively reduce equipment failure rates, extend the life of key components, and ensure the dimensional stability and surface quality of WPC door products. For periodic deep maintenance of WPC door extrusion equipment, a specific maintenance plan should be developed based on the characteristics of the wood-plastic material, focusing on addressing issues such as high wear, carbon deposits, and extended downtime. The following are the key steps for quarterly overhauls and annual maintenance:

Core Contents of Quarterly Overhauls

1. Deep Cleaning of the Screw and Barrel:

1. Disassemble the screw and clean it with a dedicated wood-plastic cleaning compound (including glass fiber reinforcement) in a circulating cycle to thoroughly remove carbon deposits and prevent chemical corrosion.

2. Inspect the screw's outer diameter for wear (radial wear ≤ 0.05mm). If it exceeds tolerance, repair it with a tungsten carbide overlay.

2. Die Flow Channel Polishing and Inspection:

1. Use diamond abrasive paste to polish the flow channel, ensuring a surface roughness Ra ≤ 0.4μm to reduce the risk of wood-plastic sticking to the mold.

2. Inspect the gap between the die and the core rod and adjust it to within the door panel thickness tolerance (usually ±0.1mm).

3. Gearbox and Transmission System Maintenance:

1. Clean the reduction gearbox and replace the lubricant (every 2000 hours). Inspect the gear meshing surfaces for wear, repair burrs, or replace the gears.

2. Calibrate the coupling for coaxiality and replace worn plum-shaped gaskets to ensure smooth transmission.

Annual Maintenance Highlights

1. Overall Equipment Performance Inspection:

1. Inspect heating elements and sensors, and replace aging components (such as thermocouples and heating coils). The temperature control error must be ≤ ±3°C.

2. Test the accuracy of instruments such as the melt pressure gauge and ammeter, and calibrate the displayed parameters.

2. Comprehensive Cooling System Cleaning:

1. Drain the water lines and clean the condenser to remove scale (using acid cleaning or a dedicated descaling agent is recommended) to prevent a decrease in cooling efficiency.

2. Inspect the water pump and vacuum pump impellers, replace rusted parts, and ensure winter antifreeze measures are in place.

3. Protection During Long-Term Downtime:

1. Store the screw in a suspended position and apply anti-rust grease (including wood flour compatibility). Apply anti-rust oil to the inner wall of the barrel and seal it with stretch film.

2. Place a desiccant in the electrical control cabinet (humidity ≤ 30% RH) to protect the circuits from moisture.

Spare Parts Management Recommendations

1. Stock high-wear parts (such as screws, barrels, and heating coils) in advance and use pre-coated anti-rust grease for packaging.

2. Establish a key lifespan record sheet, such as the gear oil change interval for the feed reducer and the bearing grease refilling time.

This in-depth maintenance can significantly extend equipment life, reduce the risk of sudden failures, and maintain the dimensional accuracy and surface quality of WPC door products.