When it comes to lubricity and mold release characteristics of finish is taken into account, as well as the opportunity to use the coating. Some finishes mold can increase the need for coating the mold.
There are four standard SPI finishes: diamond, stone, paper and Blast. Each casting surface gives a different look, from a shiny mirror-like surface (A-1 diamond) in a fairly rough, grainy texture (sand blasting with glass beads or aluminum oxide) . All four finished three grades as well.
The A-1 Diamond finish is the most perfect finish available, which means it has the lowest average roughness or the value of PR. There are no high or low peaks. For example, a scrap paper to steel gives an RA 2-4, while a diamond A-1 is the objective of fine quality, usually a PR or less. Roughness is almost incalculable.
But such a perfect finesse can be harmful in many molding applications because a number of plastics tend to stick like glue to the flawless mirror finish. Molded polystyrene on a polished wall on the right baseline with 1 or less resistance is one example. Streak lines or drawing can be displayed on the individual parts. This can be solved by the kernel flash plating, creating a surface with micro-cracks. Sealing cracks with PTFE and then re A-1 diamond finish solves the problem in more than 95% of cases.
Molding thin-walled container adds another dimension to the use of a diamond finish. Erosion of sour cream, cheese and yogurt container cottage find their products more attractive to the customer if they have a slight sheen. For this purpose, these parts require a high-gloss polished diamond with a little out of control so that the show will be brilliant. This adjustment also allows much more complete liberation of parts.
In applications molding thin-wall like this, a glossy ball explosion applied-just enough to very few interruptions perfect A-2 surface of diamond. The surface is polished again, so only a few bumps almost invisible. This finish with a coating of nickel-PTFE Nicklon will greatly improve free up some and improve mold filling.
Phenolic compounds and other thermoset almost need a perfect polish and work exceptionally well with a diamond finish. Combine that with a hard coating, protection such as chromium or chromium-diamond, and you will strengthen the mold surface and to optimize the release. Again, using a PTFE current minimal beneficial because it will not last long. Usually it's just not worth it, in our opinion. The successful use of straight PTFE depends on the presence of a grain in the mold quite ready to continue to be covered. Since the thermosetting molding requires a perfect finish of the tool, the PTFE itself has limited adhesion to the surface, and thus will fail relatively quickly.
Source: www.impreglon.com/
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