Abstract: A new method for roundness measurement of small cylinders is presented instead of the conventional rotary-scan method. By the new method,which is referred to as the stitching linear-scan method,roundness measurement of a small/micro cylinder by stitching a series of arc profiles is realized,adopting stitching in both the radial and the circumference directions at different angular positions linearly scanned by a surface form profiler,without alignment of the cylinder and a rotational datum. Description of the principle is proposed in the new method,by which a roundness measuring machine is constructed. Experiments and uncertainty analysis are presented to demonstrate the effectiveness of the method,and the results between traditional roundness measuring machine and new machine are compared as well.

Key words: Roundness measurement, Small/micro cylinder；Stitching linear-scan；Arc profile；Reference circle