Pulse effect periodic density variation appears in PTFE sintered parts

Periodic density bands appear in the axial direction of products during assisted ultrasonic/pulse sintering. Density differences are evident between different parts of the product, affecting the overall performance consistency of the product.

(1) Pressure parameter aspect: During sintering, the pressure pulse frequency resonates with the material relaxation time, producing density fluctuations, Improper pressure control directly affects the compactness and molding quality of the product. (2) Process aspect: Uneven pressure transmission or insufficient holding pressure causes densification differences among parts. (3) Material aspect: Filler sedimentation or composition segregation causes local density abnormalities. (4) Operation aspect: Uneven feeding or improper filling sequence.

(1) Implementation measure: Adjust the pulse frequency to avoid the material relaxation time range, Develop a specific operation plan based on actual production conditions, and verify the implementation effect. (2) Material selection: Use continuous constant pressure sintering instead of pulsed pressure., Establish material selection evaluation criteria, and determine the optimal solution through comparative tests. (3) Process optimization: Increase the preforming pressure and maintain sufficient holding time to ensure uniform compaction of all parts. (4) Operation improvement: Optimize the feeding method to ensure uniform filling, and use vibration-assisted feeding if necessary. (5) Preventive measure: Establish a raw material batch inspection system, regularly sample product density and mechanical properties, and establish quality trend analysis.

The essence of uneven density is inconsistent distribution or densification of the material during the '2079851475616104453; it is necessary to optimize the feeding method and pressure transmission.