The PTFE tube forming process is the most commonly used method in PTFE and includes PTFE tube forming processing plates, welding rods, sleeves, tapes, seals, diaphragms, and parts with metal inserts.
The PTFE molding method is basically composed of four stages: mixing, preforming, sintering and cooling. Preform is a preform (i.e., blank) in which PTFE powder is evenly placed into a mold and pressurized at room temperature. Sintering is the process of heating the preform above the melting point, and cooling is the process of lowering the sintering temperature to room temperature.
Part of PTFE is made by pressure above the melting point temperature, this molding mold is called a hot pressing mold, and the corresponding PTFE mold is called a cold mold.
When molding PTFE, pay attention to the influence of compression ratio (4-6 when 1 is PTFE) and molding shrinkage (2.6-4.5% when PTFE is general) on the product. The raw material collects the resin by the suspension method, and the particle size is 20-500 microns of soft powder. The compression process must be "shrunk", the preform pressure is 17-35 MPa, and the compression time depends on the thickness of the blank (e.g. 100 mm thick blank). It takes 15 minutes of compression.
When sintering, it should be noted: the heating speed is 20-120/hour, the larger the product, the slower the heating speed, the PTFE suspension resin sintering temperature is 370-380, the dispersion resin sintering temperature is low, 360-370, the sintering temperature is high.
