Surface finish Teflon

The molds have to be preserved at the end of production. For parts, which get a surface finish after the manufacturing process, it has to be ensured that Silicone-and Teflon-free preservatives are used. 

Another problem which received considerable attention, particularly in the testing stage, was that of the check valves. These valves are required to operate at a minimum pressure differential, must have excellent sealing characteristics, and must be small in size so as to reduce the clearance volume in the compression chamber. The surfaces used for sealing purposes consist of a hardened and lapped steel insert working against a finely finished Teflon disc in the poppet. 

Figure 2.33 Boiling curves for acetone boiling on Teflon-coated, mirror-finished, and rough surfaces. (From Ramilison and Lienhard, 1987. Copyright 1987 by American Society of Mechanical Engineers, New York. Reprinted with permission.)...

These are fluoropolymers (such as Teflon) or high temperature paint coatings that are bonded to the mold surface before molding takes place. The surface must be shot blasted, the coating material sprayed on, and then the mold baked to cure the finish in place. These coatings provide a uniform release surface that can have a high gloss or matt finish. 

---