Vision-based thermal drift monitoring method for machine tools

A method is presented to measure machine tool thermal drift for error compensation. A wireless microscope within a tool holder in the spindle is used to capture videos of image targets attached to the worktable. For each target, one video is captured during spindle rotation orthogonal to the worktable and another video is captured during axis translation orthogonal to the worktable. Data are collected periodically so that the three-dimensional thermal error at each target location is determined via image analysis. Experiments verify that the method measures micrometer-level tool-to-workpiece thermal drift for error model development and thermal drift compensation.