Surface modification for SMC moulding tools by laser remelting

摘要

Due to their excellent material properties and their largely adjustable functionality, duromer components made of SMC (sheet moulding compound), which are mass-produced by compression moulding, are used in an increasing number of industries. Despite intensive development work in the field of stable production processes in compression moulding and a high-quality topcoat, the economic damage caused by paint failures is still very high at 20-30%. Both, the demoulding process of the SMC components and their paintability are significantly influenced by the surface structure/topography of the moulding tool. One method of targeted layer modification is laser remelting. The paper presents the possibilities of laser remelting with a 20 W fiber laser by IPG Laser GmbH in detail. In the course of this, the influence of the inert gas use will be explained and a process chamber developed for this task will be evaluated. The processing results for hardened and tempered as well as soft annealed cold work steel are compared. Moreover, the influence of the laser processing on the heat treatment is derived. The residual surface was characterized and investigated by SEM (scanning electron microscopy) and EDX (energy dispersive X-ray spectroscopy). Furthermore, measurements of microhardness and surface roughness were performed.