Insufficient surface plasticization in polyphenylene sulfide (PPS) sintering

Unmelted powder remains on the surface of PPS sintered parts. Surface defects directly affect the appearance quality and service performance of the product, and are particularly obvious in transparent products. This defect affects the appearance quality of the product and reduces the market competitiveness of the product.

(1) Temperature parameter aspect: The sintering temperature does not reach the complete melting temperature of PPS (~285℃); temperature deviations directly affect the physical and chemical state of the material and the reaction process. (2) Process time aspect: The heating rate is too fast, and the time for the surface and the core to arrive simultaneously is insufficient; improper time control causes the reaction or cooling process to fail to meet process requirements, affecting the final performance of the product. (3) Mold aspect: The mold surface finish is insufficient or maintenance is poor. (4) Process aspect: Improper temperature or pressure parameters affect the surface molding quality. (5) Material aspect: The shrinkage or rheological characteristics of the resin formulation affect the surface replication accuracy.

(1) Parameter adjustment: Increase the sintering temperature to 300-320℃; it is recommended that each adjustment be 5-10℃, while monitoring product quality changes to avoid new defects caused by excessively high temperature. (2) Process optimization: Appropriately extend the holding time, determine a reasonable time according to the product wall thickness and material characteristics, and balance production efficiency and quality. (3) Implementation measure: Ensure that the product surface is fully heated., formulate specific operation plans in combination with actual production conditions, and verify the implementation effect. (4) Preventive measure: Establish a sound process control standard and quality inspection system, and regularly review process data for continuous optimization.

Surface defects are the result of the combined effects of mold state, process parameters, and material formulation, and each factor needs to be systematically investigated and optimized in a targeted manner.