AGMA 13FTM05 PDF

To date, grinding, according to the German DIN Standard 8580, is "machining with geometrically undefined cutting edges" while other machining processes such as turning and milling are classified as processes with "geometrically defined cutting edges". New abrasive grains, called PSG and developed by 3M, stand this definition on its head. For the first time, grinding wheels made with PSG, called CubitronTM II, can claim to be made up of "geometrically defined cutting edges" as each and every grain is exactly the same engineered shape. Hence, it might be more appropriate to talk about "micro-milling" rather than grinding. This is borne out by looking at the resulting "flowing" chips which are akin to chips seen in milling operations, just finer.

These free-flowing chips no longer clog up the grinding wheel and, therefore, the grinding wheel remains free-cutting and dressing becomes only necessary due to loss of from rather than loss of cutting ability. In repeated tests, this has shown to drastically reduce the risk of burning and to give consistent and predictable results. Furthermore, tests and subsequent long term trials under production conditions have shown that grinding time can be cut in most cases by at least 50% in comparison to grinding wheels made of standard ceramic abrasives.

Based on more than 100 carefully monitored and documented gear grinding trials, this paper will demonstrate how CubitronTM II grinding wheels work both in continuous generating grinding of car and truck gears, and in form grinding of large diameter gears for wind generators, for example. Furthermore, the paper will discuss chip formation, filmed with high resolution slow motion; and the benefits of the freeflowing chips in terms of resulting consistent surface finish, superior form holding and extended dressing cycles.