New Measurement Method for Motion Accuracy of NC Machine Tools by Link Mechanism. 3rd Report. Measurement of Accuracy for Circular Motion with a Samll Radius and Linear Motion Containing a Square Corner.

Abstract

This paper describes the application of the LM measurement method for measuring two types of motion accuracy, trajectory accuracy of the circular motion with a small radius and the linear motion containing a square corner, on a machining center. The measured results for both the motion paths have high precision and good repeatability and confirm the validity of the LM method for the measuring purpose. It is verified for the tested machining center that the radius decrease of an actual path with respect to its specified radius R is in proportion to the value of F2 /R in the circular motions, and the error around the square corner is proportional to the feed rate F in the linear motion paths. Two potential profile errors in contour machining with a high feed rate are demonstrated by the actual examples, i.e. the error caused by different radius decrease relative to neighboring interpolation circular arcs in tool path and the error caused by the combined influence of the feed rate change near the connection point of two motion blocks and the radius decrease of circular path.