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Common Problems in the Production of UPVC Injection Fittings
Release Time：2025-07-18
Common Problems in the Production of UPVC Injection Fittings
1. Excessive Moisture Content in Raw Materials, Resulting in Bubbles/Voids in Products
Cause:
UPVC raw materials absorb moisture or are not thoroughly dried, and the moisture vaporizes during injection molding.
Solutions:
Dry the raw materials at 60-80℃ for 4-6 hours before use to ensure the moisture content is less than 0.1%.
Install a hopper dryer to keep the raw materials dry during the production process.
2. Impurities in Raw Materials, Causing Black Spots/Particles on the Surface of Products
Cause:
The raw materials are mixed with metal chips, dust, or the recycled materials are not thoroughly screened.
Solutions:
Strictly screen raw materials and avoid using contaminated or low-quality recycled materials.
Regularly clean the hopper and screw, and install a raw material filter.
3. Improper Raw Material Formulation, Leading to Insufficient Strength or Easy Breakage of Products
Cause:
Excessive addition of calcium powder, and unbalanced proportion of stabilizers/plasticizers.
Solutions:
Optimize the formula, control the amount of calcium powder added to be ≤10%, and ensure that the proportion of stabilizers (such as lead salt/calcium-zinc composite stabilizer) meets the standards.
Test the melt index (MI) of raw materials to ensure that the fluidity meets the injection molding requirements.
