Exact straightness reconstruction for on-machine measuring precision workpiece

A new frequency-domain method, which can reconstruct straightness profile of workpiece exactly for on-machine measurement, has successfully been developed. The proposed method is based on difference measurement and can use two or three displacement probes. It possesses following characteristics: (i) adapting to long or short workpiece, (ii) assuming no prior knowledge, (iii) employing large shears and (iv) reconstructing any surface including smooth, non-smooth, periodic and non-periodic profile with no theoretical error. The theoretical analysis and simulation justify the effectiveness of this method. Finally, the measurement system consisting of two non-contact capacitive probes is built and evaluated experimentally on a diamond turning machine.