Abstract
This paper deals with monitoring of spindle displacement of machine tool by utilizing position sensitive detector(:PSD). PSD and miniature LD module are arranged far from each other at opposite side of rotating spindle with slit in radial direction. PSD detects the position of part of laser light cut by the slit. The position change corresponds with the slit displacement. And elongation between the slit and the end surface of spindle is estimated as a homogeneous thermal expansion from temperature increase of the portion measured by non-contact surface thermometer. According to sum of the slit displacement and the expansion, tool position is controlled by piezoelectric actuator. It is clarified that the controlled tool position coincides well with the position of end surface of spindle under continuous and discontinuous operations.
