HIGH-PERFORMANCE CUTTING TOOLS WITH A SOLID LUBRICANT PHYSICALLY VAPOR-DEPOSITED COATING

The closed-field unbalanced magnetron sputtering technique allows one to deposit solid lubricants onto cutting tools such as end mills, dril ls and cemented-carbide inserts. The adherence and coating uniformity obtained are excellent. The use of a multimagnetron system allows one to control the coating composition and coating build-up sequence caref ully. The performance of the tools with the ''soft'' solid lubricant c oatings is very astonishing (patents pending). The low coefficient of friction and a low affinity to allow materials such as aluminium, tita nium, copper and precious metals allows machining at very high product ion rates. Industrial tests have given machining results with soft-coa ted high speed steel tools which are better by a factor of more than 4 than those obtained with the uncoated cemented-carbide tools used at present. The main improvements are in the area of workpiece surface ro ughness, productivity and tool life. In particular the feed rate durin g milling can be increased without sacrifice in workpiece surface fini sh. The most spectacular results are obtained with the machining of pl atinum alloys.