Surface location error in robotic milling: Effect of combined low frequency and high frequency vibration modes

This paper describes surface location error (SLE) for serial kinematic robot milling. It includes frequency-domain models for milling stability and SLE, which both use a mechanistic force model and tool tip frequency response functions as inputs. Based on the predictions, experimental conditions are selected and SLE experiments are completed for a selected geometry and 6061-T6 aluminum workpieces. Measurements and predictions are compared and the predictions are used to compensate the workpiece geometry and reduce SLE. It is observed that, due to the presence of both low stiffness, low frequency robot modes and high frequency tool-holder-spindle modes, the SLE is large, but nearly independent of spindle speed for the available range of spindle speeds.