Laser-based and CAx-assisted system solution for the automated mold repair - ToolRep

Plastic injection molding is one of the most cost-effective manufacturing technologies for large-scale production. Surface structuring of molds is used to realize design or technical features on plastic parts by replication and its importance has increased significantly in the last years. Finely structured surfaces are applied to the molds in order to give a special product design or functionality to the final plastic part. Grained plastic parts are used in the automobile industry, for instance, where they can be found in dashboards or impact absorbers. In this context, laser surface structuring has become more and more suitable and available for industrial applications. [1] During the plastic injection process, wear can occur by using fiber-reinforced plastic material or damages ar e caused due to wrong handling. In this case, repair is hardly possible these days or it requires a high amount of manual effort. This is a disadvantage for the manufacturing company as it leads to new time-consuming and costly purchases, long repair times or even production stop. In the project ToolRep (contract no. 02P14A032), which is funded by the German Federal Ministry of Education and Research (BMBF), Fraunhofer IPT and the Institute for Optical Systems Konstanz as well as four industrial partners jointly develop a holistic repair solution. The objective of the research project ToolRep is the realization of a hybrid laser machining center for the automated repair of textured injection molds. For this purpose, a complete and consistent process chain for mold repair has been developed as an automated laser-based process sequence. The combination of wirebased laser metal deposition (LMD-W) and laser structuring within one single machine tool, which is controlled by an integrated optical metrology solution based on low coherence interferometry [2], offers the end user significant competitive advantages due to shorter set-up times and a lower space requirement. In addition to the optical metrology, a control technology as well as process monitoring and controlling routines ensure stable laser processes. New algorithms for the software-based path planning for both laser processes as well as for the digital structural repair known as texture synthesis are currently implemented into an existing CAM software CALM developed by Fraunhofer IPT. All th e results will be merged into a final machine tool demonstrator, which is based on already existing multi-axis machining concept. Ultimately, the project results put the project partners in the position where they can offer manufacturers and users a quick and complete repair from a single source.