PTFE is mainly molded, hydraulic, push, extrusion, spraying, bonding, welding and winding the most common molding technology. The first five are directly processed into products with PTFE resin, and the latter three are processed into various products with PTFE plastic plates or thin strips. In addition to rolling method, thermoforming method and other molding methods. Now briefly introduce a variety of molding methods.

01 Molding Method

Molding mostly uses suspension resin, when the thickness of less than 1.5mm thin plate, it is necessary to use dispersion resin. The process is as follows: resin-sieving (suspended resin is mashed, loosened and sieved through a 20-mesh sieve)-press (PTFE powder loaded into the mold is under a pressure of 20-235Mpa, compaction and molding by press)-sintering (sintering in a sintering furnace at a temperature of 370 ℃-380 ℃)-molding finished products (after cooling and setting in the mold or free state, they become the required plates, rods, tubes, gaskets and packing products, etc.).

02 Hydraulic method

Hydraulic method, also known as isobaric method or rubber bag method, is the 1 special method for making PTFE products. Hydraulic pressure is applied to the rubber bag to expand PTFE resin to the mold, so that it is compacted and sintered into products. The basic operation process is: place the rubber bag in the outer mold-connect the water pump, filling tap water to make the rubber bag expand into a cylindrical shape-resin is evenly added between the bag and the outer mold-the mold is closed-water is continuously filled to gradually increase the water pressure, when the pressure reaches 12-13Mpa, the water is kept for 30min, and then the water is discharged-decompression, mold removal, sintering and cooling are the preproducts with smooth appearance.

03 Push method

Pushing is also called paste extrusion molding. Dispersion resin sieved with 20-30 mesh and organic liquid (toluene, petroleum ether, solvent oil, etc.) are prepared into a 1:5 paste mixture, pre-pressed into a thick-walled cylindrical blank, put into the barrel of the pushing press, heated, pressed and formed with a plunger, sintered at 360-380 ℃ after drying, and cooled to obtain strong pressing tubes, rods and other products.

04 Extrusion Method

Extrusion molding can be divided into screw extrusion and plunger extrusion. The pre-sintered resin after crushing and sieving is added to the cylinder. Through the rotation of the screw or the reciprocating push of the plunger, the raw materials are compacted and transported to the extruder. At 360-400 ℃, various pipe and rod products are formed by continuous extrusion, sintering and cooling.

05 Spraying method

The spraying method has two processes: PTFE emulsion spraying and sintering film forming and PTFE resin powder plasma direct spraying film forming.