Diamond Tool Wear in the Ultra-Precision Cutting of Large Electroless Nickel Coated Molding Dies

In recent years, in a field of space science, large and high precision aspherical molding dies which are used to make aspherical thin foil mirrors for the hard Xray telescope are needed. Therefore to establish the ultra-precision cutting method for these dies is overly expected. In the actual manufacturing, the largemolding die is required to have both high accurate shape accuracy and very small surface roughness as the finished product. To machine the large molding die which has these high accuracies, we should know factors to cause various errors such as shape error and surface roughness and so on. Because it is necessary to machine the large molding die by using NC machining system that automatically corrects shape error finally. Especially, the tool wear of diamond tool is one of the big factors that influences shape error and surface roughness, so it needs to correct the amount of tool wear while ultra-precision cutting of large molding dies. From these points of view, in this research, a tool wear of diamond tool which is used in the ultra-precision cutting of large electroless nickel coated molding dies is considered with an on-machine measurement and observation system.