Quick algorithm of maximum inscribed circle method for roundness evaluation

The evaluation of roundness based on the maximum inscribed circle method is an important method suitable for the circle with the maximum material condition like an internal bore. The maximum inscribed circle is determined by three data points according to the criteria of the maximum inscribed circle. The mathematical formulae has been developed for the establishment of the center of the maximum inscribed circle. A quick algorithm has been proposed for solving maximum inscribed circle. There is no principle error or method error in the results calculated by the formulae. Three examples are given in the paper. The validated results show that the method gives an efficient approach to solve the roundness problems on the maximum inscribed circle, especially when the number of data points is large.