For coating removal use
PCD scrapers, Tearitoff or coarse diamond segments
In general coarse diamond segments are used for coating removal, however there are two other special products that can increase the productivity of your floor grinder for coating removal known as PCD scrapers and Tearitoff diamond wheels.
PCD scraper cupwheels pictured above contain small “teeth” that shave off the coatings and are most efficient when used for very thick or self leveling coatings.
Polycrystalline Diamond (PCD) scraper wheels rapidly remove thick coatings by penetrating them and scraping them off. After using the PCD scrapers the floor usually needs diamond grinding because the scrapers are not meant to grind the concrete, they are only used for coating removal and may score the concrete surface.
The unique shape of the rods molded into the segments of the Tearitoff wheel allow it to cut deeper into hard concrete and heavy coatings including soft coatings and glue as if it were one step coarser in diamond grit size. That can mean reducing a grinding step by removing coatings without leaving a coarse scratch pattern.
Coarse diamonds will also cut through coatings if there is enough bite in the size of the diamond to penetrate the coating and score it so a 16/20 grit is normally recommended or for thicker coatings coarse grits sizes down to 10 grit can be used, but they leave deep score marks on the surface. These type of wheels also depend on the concrete being soft enough to keep the diamonds exposed. See Grinding Hard Concrete for more information about keeping diamonds exposed.
Acrylics, “DIY paving paints” and some glues become sticky with the heat that is generated by the floor grinder, especially when multiple coats have been applied over the years or when the concrete underneath the coating is hard. These coatings soften and stick to the segments instead of grinding away cleanly. Swapping to a Tearitoff wheel will eliminate this problem and using a PCD will be inefficient because these coatings are not very thick.
Scraping instead of grinding
Sometimes a long handled scraper can be useful to scrape away most of the coating before diamond grinding. If the coating is a problem to remove with a diamond cupwheel try coarser diamonds, or try a PCD scraper disc or take smaller bites into the coating each time. PCD scraper discs will be most successful on hard concrete as will soft bond, very-coarse diamonds down to 10 grit. Coarse diamond 30/40 grit with the right bond will be better on soft to medium hardness concrete.