Cutting tool material and coatings HSS cutting tool materials For Walter Prototyp milling cutters, four groups of high-speed steel are used HSS H

Cutting tool material and coatings HSS cutting tool materials For Walter Prototyp milling cutters, four groups of high-speed steel are used. HSS High-speed steel for general applications (side and face milling cutters) HSS-E High-speed steel with 5 % Co to withstand higher stress, especially thermal stress HSS-ECo8 High-speed steel with 8 % Co for highest possible heat resistance, corresponds to US standard designation M 42 (end mills for general use, available in standard dimensions and with Morse taper shank, shell end mills) HSS-E-PM High-speed steel manufactured using powder metallurgy with extremely high alloy content Advantages high purity and consistency of microstructure, outstanding wear resistance and thermal loading capability (end mills and shell end mills for more demanding applications) Carbide cutting tool materials Carbides mainly consist of tungsten carbide (WC) as the hard material and cobalt (Co) as the binding material. In the majority of cases, the cobalt content is between 6 and 12 %. The following rule generally applies The higher the cobalt content, the tougher the material, but the less wear resistance and vice-versa. Another determining factor in carbides is the grain size. The hardness increases as the grain size decreases. Coatings Surface coating has developed into a proven technological process for improving the performance of metal cutting tools. By contrast with surface treatment, the tool surface remains chemically unaltered and a thin layer is applied. For Walter Prototyp high-speed steel and carbide tools, the coating is produced by the PVD method, which works at process temperatures of below 600 °C and does not, therefore, result in any change to the base material. Hard material layers have a higher hardness and wear resistance than the cutting material itself. In addition, they help to improve the low-friction quality of the tool surface keep the cutting tool material and the material to be machined apart act as a thermal insulation layer Coated tools not only have a longer life, they can also be used with higher cutting speeds and feed rates. Surface treatment / Method / coating coating Property Color uncoated No treatment uncoated TAX TiAlN coating Universal coating for solid carbide milling cutters black-violet TAZ TiAlN / zirconium nitride coating High-performance layer specially developed for machining steel chemical resistance to emulsions and oils effective against built up edge champagne TAS Titanium aluminum silicon nitride coating Very hard and highly heat resistant coating for machining hardened materials copper CRN Chromium nitride coating Very thin layer with high degree of toughness minimised coating roughness for excellent chip flow, especially with aluminum workpieces rainbow-colored DIA Diamond coating For machining graphite and AISi alloys grey H9 ACN Aluminum chromium nitride coating High-performance coating with particularly low friction for titanium machining tools but also for HSS tools blue-violet oasai E 319 Technical information Milling WALTER PROTOTYP