K20 inserts designed and manufactured by Carmex, are uncoated inserts made of micro-grades layers designed for stock removal machining on CNC and sliding headstock machine tools. The use of this insert finds its place in machining at low chip flow temperature, but which also needs excellent sharpening to facilitate chip penetration and removal. They find the excellent application for machining aluminum alloys, aluminum castings, copper and copper alloys, CW600 brass, lead-free brass (example CW510L), ecobrass, nonferrous materials such as electrolytic copper, hard rubber, plastics, fibers and plastics.

For small-batch production and finishing operations, the K20 insert can also be used for machining easy-to-remove stainless steels, such as AISI 303, AISI 320, and malleable cast iron For these materials, use in turning without interrupted cutting is also preferred. The lack of coating being very sharp, it helps and facilitates the penetration of the tool into the workpiece during chip removal, It is also further facilitated by the lapping of the tool sharpening surface which helps the sliding of the tool.

Parts made with these types of inserts allow the production of turned valve parts in the faucet industry, parts for automotive, Special seal and special valves made of plastic fiber material, turned electrical and electronic components made of copper. They are also good for making parts for watches of the highest quality, turned parts for high fashion. The cutting speed parameters for the insert made of K20, turn out to be lower than the coated inserts. The feed rate of the tool depends heavily on the material to be machined, the coolant used, the surface finish and roughness of the workpiece as well as the depth of cut of the insert.