Fraunhofer Institute for Laser Technology ILT Machine tool for laser-polishing tools and moulds automates stubbornly manual task
The state of the art for polishing in tool and mould making is still manual technology. But economic and time-related considerations are driving a demand for automated polishing techniques that can be applied to complex 3D surfaces. Accordingly, Maschinenfabrik Arnold, S&F Systemtechnik and the Fraunhofer Institute for Laser Technology ILT got together to develop a machine tool for laser-polishing metallic parts.
Polishing via laser radiation involves remelting a thin surface layer of the workpiece and subsequently smoothing the surface roughness due to surface tension. This approach is innovative because the active principle (remelting) is fundamentally different from that of conventional grinding and polishing (abrasion).
The jointly developed machine tool is based on a 5-axis portal machine concept for positioning workpieces and performing slow feed motions. This system is combined with a highly dynamic 3-axis laser scanner to achieve the requisite process speeds approaching 1 m/sec. Owing to the machine kinematics with 5+3 axes, special demands are made upon the CAM-NC data chain. Fraunhofer ILT is developing a solution that lets the operator continue working with the CAM system being used for milling; the same system is available for laser-polishing tool-path generation.
The laser-polishing system offers x-y-z travel of 500 x 800 x 400 mm, travel of ±95° in the swivelling a-axis, and full 360° rotation in the c-axis. Its 450-mm-diameter worktable holds workpieces up to 350 mm high and weighing 100 kg. The machine uses a 500-W Rofin fibre laser and is equipped with a Siemens Sinumerik 840D control.
Fraunhofer Institute for Laser Technology ILT