Injection Molding
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Sink marks at weld line positions of styrene-acrylonitrile copolymer injection molded products
Problem Phenomenon
Sink marks appear at weld line positions of the product, affecting product appearance and service performance.
This problem often occurs in styrene-acrylonitrile copolymer '2079851475616104452 and needs to be solved in time.
Cause Analysis
(1) Improper processing temperature setting (200-260°C range), causing unstable melt quality
(2) Styrene-acrylonitrile copolymer material characteristics (transparent, heat-resistant, chemical-resistant) are sensitive to this defect
(3) Poor mold design or condition, affecting molding quality
(4) Process parameters (injection speed, holding pressure, etc.) are set unreasonably
(5) Improper raw material pretreatment or regrind use problems
Solution
(1) First check and optimize barrel temperature to ensure it is reasonably set within the 200-260°C range
(2) Adjust injection speed and holding pressure; the recommended holding pressure for styrene-acrylonitrile copolymer is 80-120MPa
(3) Check mold temperature (50-90°C range) and venting condition
(4) Ensure the raw material is fully dried (70-80°C, 3-4h)
(5) Control the regrind proportion to no more than 15-20% and regularly check equipment condition
Key Takeaway
This problem needs to be systematically solved from three aspects: material characteristics, process parameters and mold conditions.
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