What should I do if the extruded wall thickness of WPC door is uneven?

As a professional manufacturer specializing in WPC door extrusion lines, Yongte Company is dedicated to providing customers with one-stop solutions, from equipment supply to comprehensive technical support. We offer not only high-performance production line systems but also professional on-site installation and meticulous commissioning services. Many wood-plastic door manufacturers encounter issues such as uneven extruded wall thickness. Our expert engineers can promptly diagnose these problems by analyzing equipment operating parameters and material properties to identify the root cause. Subsequently, targeted adjustments are implemented through a systematic commissioning process. This ensures uniform wall thickness and stable product dimensions, significantly improving both product quality yield and production efficiency. The following commissioning methods are provided for customer reference.

I. Scope of Application

PVC base wood-plastic door panel/special-shaped profile extrusion production line, designed to address issues such as uneven thickness on one side, vertical thickness variation, localized thickness differences, or overall thickness imbalance, with adjustments made in priority order.

II. Tiered Debugging Process (Priority Order: Die → Temperature → Setting → Traction → Raw Material)

Step 1: Adjust die clearance (highest priority; preferred for local unevenities)

The equipment operates at low speed; shut down and lock it for safe operation.

At each point along the entire circumference of the mouth mold, measure the actual clearance every 5–10 cm using a feeler gauge.

Adjustment rules: If the wall thickness is excessive, tighten the bolts (by 15°–30°) to reduce the clearance; if the wall thickness is insufficient, loosen the bolts (by 15°–30°) to increase the clearance.

Make a single fine adjustment; after adjustment, start the device and let it stabilize for 3–5 minutes before retesting. Do not make large adjustments in one go.

Quality standard: Total weekly gap deviation ≤ 0.05 mm

Step 2: Fine-tune the zone temperatures (if temperature distribution remains uneven after gap correction)

Excessive local wall thickness: Corresponding regions exhibit a slight temperature increase (2–3°C) and reduced melt flow rate.

Reduced local wall thickness: Corresponding area exhibits mild cooling (2–3°C), increasing melt resistance

Top/bottom/Left/right overall thickness variation: Adjust the temperature of the corresponding zone on the die head simultaneously, keeping the temperature difference within 5°C

Step 3: Finalize System Diagnosis and Correction

Vacuum deficiency: Clean the vacuum circuit and filter, and restore it to standard vacuum level; for localized collapse or thinning, apply additional vacuum pressure only to those areas

Cooling anomaly: Clear blocked water pipes and increase cooling water flow in thin sections

Position Offset: Realign the centers of the die and setting mold to prevent unilateral stress

Step 4: Match traction and extrusion speeds (prioritize overall thickness consistency)

The overall thickness of the product is substantial: slightly increase the traction speed / reduce the main screw rotation speed / adjust the feeding rate

The overall thickness of the product is reduced: slightly lower traction speed / increased main screw rotation speed / higher feed rate

The wall thickness varies intermittently: reduce the main unit speed, maintain constant traction tension, and ensure stable linear velocity.

Step 5: Raw Material and Blending Adjustment (to be performed if the above adjustments prove ineffective)

Moisture absorption in flour powder / uneven particle size: Re-dry and sieve; replace with qualified batch of raw materials.

Poor liquidity: Supplement with appropriate amounts of both internal and external lubricants.

Uneven mixing: Extend the hot-mixing/cold-mixing time to ensure material homogeneity.

III. Comparison Table of Common Fault Symptoms, Causes, and Quick Solutions

IV. Contraindications & Precautions for the Procedure

It is strictly prohibited to make excessive turns of the die bolt in a single operation, as this may cause deformation of the profile, wave edges, or tearing.

The temperature adjustment should not exceed 3°C per operation; make repeated minor adjustments only. Significant temperature changes across different ranges are prohibited.

Before debugging, ensure the die and setting die are aligned; otherwise, debugging will be ineffective.

Before each shift, clean the vacuum air passages, water passages, and the surface area of die molds to prevent abnormal wall thickness in later stages.

After changing the raw material batch, prioritize retesting temperature and clearance before resuming normal production.

V. Standards for Successful Acceptance

Full plate wall thickness deviation ≤ ±0.2 mm

The profile surface is smooth, free from depressions, bulges, or wave patterns.

Production was maintained continuously for 30 minutes with no significant fluctuations in wall thickness.