Molding is the most common molding method for processing PTFE films. Most of them use PTFE suspension resin, which consists of three steps: preforming, sintering and cooling. That is, the tetrafluoro powdered resin is first cold-formed in a metal grinding tool at a pressure of 10 MPa to 30 MPa at room temperature to form a dense preform, which is then sintered at 370 ° C to 380 ° C to change from a crystalline phase. In the amorphous phase, a dense, continuous, transparent elastomer is formed, which is then cooled into a crystalline phase by cooling down to obtain a tetrafluorofilm. Most of the products obtained by compression molding retain the shape of the preform, and this method can only produce articles having a relatively simple and regular geometry. As for the production of more complicated products, it is mechanically processed using a simple product or cold-pressed after sintering. After cooling and setting in a mold or in a free state, various parts are produced.
As with pure PTFE processing, the processing of filled PTFE is in most cases molded by compression molding.
The PTFE film extrusion method is characterized in that it can be continuously formed and is a continuous molding process. Generally divided into screw extrusion and plunger extrusion. The pulverized pre-sintered resin is added to the barrel, and the raw material is compacted and conveyed to the extruder through the rotation of the screw or the reciprocating push of the plunger, and is continuously extruded at a temperature of 360 ° C to 400 ° C. Sintering and cooling to form various PTFE films, tubes and rod materials.