This paper describes the way of ultrapreciso turning aspherical optical reflectors with diamond tools and analyzes the factors whih influence surface finish of mirrors

circulity and figure accurancy. This paper also introduces the influence of machine spindle asynchronous error on surface finish and analyzes the reason for producing asynchronous error motion and the method of reducing asynchronous error value systematically. In order to get rid of the influence of workpiece chucking distortion on machining accuracy of mirror

we used an approaching method from poiat to point to get rid of workpiece chucking distortion step by step4

so that the clrculity of mirror achieved were 0.3μm in machining.