This paper describes a high performance finishing system for metallic molds of PET bottles. A mounted abrasive tool is attached to the tip of an industrial robot through a force sensor. Its motion in tangent direction and contact force in normal direction are delicately controlled so that a resultant force among a motion friction force, viscous friction force, coulomb friction force and so on can track a desired value. In other words, the surface of the mold is polished by the resultant force. In order to avoid undesirable over polishing, the rotation of the mounted abrasive tool is locked or is controlled with considerably low speed, e.g., from 1 [deg/s] to 10 [deg/s]. This technique is applied to an open architectural industrial robot FS-20, so that a useful finishing system can be easily realized. Polishing experiments demonstrate the effectiveness and promise of the proposed finishing system.
