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, drills 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 carefully. The performance of the tools with the ''soft'' solid lubricant coatings is very astonishing (patents pending). The low coefficient of friction and a low affinity to allow materials such as aluminium, titanium, copper and precious metals allows machining at very high production rates. Industrial tests have given machining results with soft-coated 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 roughness, productivity and tool life. In particular the feed rate during milling can be increased without sacrifice in workpiece surface finish. The most spectacular results are obtained with the machining of platinum alloys.