Ultraprecision Cutting of Nickel Plated Mold for X-Ray Mirror

To improve the machining preciseness of X-ray telescope mirrors for astronomical use, the molds of electroless nickel and electro nickel are diamond-turned, and the tool wear and machining accuracy are then quantitatively evaluated. The machined surface roughness is measured and discussed in terms of the effects of cutting conditions on the resulting quality. Finally, the actual nickel-plated molds of X-ray mirrors are test cut, and their form accuracy and surface roughness are measured and evaluated. These experiments reveal that a surface roughness of 0.5 nm Ra and a form accuracy of 0.1 μm P-V can be obtained under the optimized cutting conditions.