A study on dynamic characteristic of manipulator for lapping

Abstract

his study introduces a method for designing a manipulator and analyzing the static and dynamic characteristics of a system for the automation of large area lapping. Most surface lapping processes in the current mold industry are performed by hand, which requires a lot of cost and a long processing time. However, due to the lack of manpower supply and difficulties in nurturing high-quality manpower, the lack of manpower has emerged, and the automation of the surface finishing process is drawing attention from home and abroad. Lapping process is divided into the step of removing the remaining milling tool mark on the workpiece surface after machining and the step of correcting the shape error of the mold. High stiffness is required for the manipulator to perform the following processes. Therefore, the parallelogram structure type manipulator was considered in the design, and the design of the joint was conducted to have the proper stiffness for the lapping process. Evaluation and analysis were performed through multibody dynamics simulations. In the analysis process, the frequency response of each axis was obtained by experimental modal analysis of the system through impact test. In addition, the simulation results were compared and evaluated by comparing the experimental results of the dynamic compliance, which is the dynamic characteristics of the system at the end of the robot, confirmed by the sweep test. And static compliance according to the configuration of the manipulator was investigated through the evaluated simulation model, and the results were verified through experiments. In the lapping experiments, the influence of the manipulator dynamics on the lapping surface was investigated, and the 100 μm offset error was removed clearly and the tool mark removal process was performed. The surface within surface roughness level of 0.3 μm was achieved in tool mark removal process. And, the lapping surface data was analyzed in the spatial frequency domain to confirm the effect of the dynamic characteristics of the system on the machined surface.