Measurement method of Wolter-I type mandrel based on a contact-type profilometer

Contraposing the surface quality testing of a Wolter-I type mandrel after ultraprecise turning, we propose a measuring method based on a contact-type profilometer and fabricate an adjusting device to assist in measurements. By coordinating probe translational motion in the Z and Y directions, this device provides 6 degrees of freedom. Extracting the feature point on the curve of a meridian section contour, the measurement data of the two aspherical surfaces that constitute a Wolter-I type mandrel can be segregated. This feature point is used as a reference point to make the measurement coordinate and machine coordinate systems coincide with each other in order to calculate the dimensional errors of the mandrel. By choosing samples of different lengths, some property indexes of the mandrel surface, such as roughness, waviness, and form error, can be extracted from the contour error signals via the wavelet transform method. This proposed method can solve the problem that the aspheric surface dimension error...