Memory effect appears in cold-pressed sintered PTFE products

Sintered products return to their pre-sintering shape when reheated above Tg. This problem is relatively common in sintering molding production and requires comprehensive analysis and solution from multiple aspects of material, process, and equipment.

(1) Stress distribution aspect: Molecular chain orientation and internal stress generated during preforming are not completely eliminated by the sintering process, Internal stress concentration causes the product to crack or deform during subsequent use. (2) Material aspect: Fluctuations in raw material performance indicators or insufficient pretreatment affect molding quality. (3) Process aspect: Control deviation of key process parameters causes the '2079851475616104453 to deviate from optimal conditions. (4) Equipment aspect: Equipment precision and maintenance status affect the stable execution of process parameters.

(1) Process optimization: Extend the sintering holding time to eliminate molecular memory, Determine a reasonable time according to product wall thickness and material characteristics, balancing production efficiency and quality. (2) Material selection: Use free sintering (without constraining shrinkage) to reduce the introduction of internal stress., Establish material selection evaluation criteria, and determine the optimal solution through comparative tests. (3) Process optimization: Determine the optimal process parameter window through systematic tests and establish standardized operating procedures. (4) Quality control: Strengthen process monitoring and product inspection, Establish a defect early-warning and traceability mechanism. (5) Preventive measure: Establish sound process control standards and a quality inspection system, and regularly review process data for continuous optimization.

This problem requires comprehensive analysis from multiple dimensions of material, process, equipment, and operation, and should be solved by systematically optimizing process parameters and the quality control system.