Research Of Calibration And System Testing Of Micro-nano CMM

The three coordinate measuring machine(CMM) is the main measuring instrument inthree-dimensional directions. With the development of the modern industry, nano-CMMand micro/nano contact probe with its measuring accuracy reaching nanometer level inthree-dimensional directions is becoming the research hot spot in many domestic andforeign universities and research institutes.The paper briefly introduces the development status of Nano-CMM at homeand abroad as well as three-dimensional probe. The three-dimensionalmeasuring probe with wide measuring range and high precision has beenproposed detailedly. The probe is mainly composed by a threedegree-of-freedom optical sensor, a suspension mechanism and probe. And thesystem composition, structural characteristics and control flow of themicro-nano CMM were introduced comprehensively and detailedly.Several different experimental systems is built to test the stability, range,repeatability, and force of the probe. Experimental results show that: the probemeasured range is±20μm×±20μm×10μm, the standard deviation of therepeatability is less than30nm and stiffness is less than0.5mN/μm. Then theintegration of the probe and the machine is completed. And the calibration ofprobe are carried out later. Then the probe errors are also analyzedsystematically.The measuring precision and the measuring function of the micro-nano CMM weretested from the point repeatability, flatness error, length, step height, the threedimensional profile of the convex lens, roundness and some other aspects with the useof some special standard components (such as master ball and ring gauge) or first gaugeblocks. And the compensation of equivalent diameter of probe is accomplished. Themeasuring results show: in the functional testing, the xyz axes point repeatability isaround20nm normally, the deviations of flatness errors in the xyz axes are about20nmwith the standard deviation within15nm, and the deviations of lengths in the xyz axesare approximately25nm with the standard deviation less than50nm. By the test resultsof the planeness of standard component, which verify that the measuring accuracy ofmicro/nano CMM and probe can reach nano-precision.