High-performance tools are geometrically complex, highly stressed components made of carbide. The time- and resource-saving production of such complex components is an important economic factor for tool manufacturers. The production of asymmetrical cutting edges is one of the greatest challenges in tool manufacturing: The cutting tools used are subjected to high stresses and therefore have only a short service life. In addition, current methods are only suitable to a limited extent for the preparation of asymmetrical cutting edge geometries, such as those found in toolmaking.
Efficient preparation of cutting edges has many advantages: due to process specific cutting edge geometries, the life of cutting tools can be extended by up to 300 percent; manufacturing costs and the duration of manufacturing processes can be significantly reduced. Another advantage is that valuable resources such as carbide, coolant and energy are conserved.
If the brushing process is carried out directly in the grinding machine, even complex cutting edges can be produced faster, more flexibly and more cost-effectively than before. However, industrial implementation has not yet taken place due to the lack of process strategies and the complex, manual programming of the brushing process. The Fraunhofer IPT and its partners have closed this gap with the "BrushtoCut" project.
The project team developed a comprehensive technology package that allows 5-axis brushing to be integrated directly into a machine tool for machining tools with complexly shaped cutting edges. In doing so, the Fraunhofer IPT performed pioneering work, because until then no development project had considered 5-axis brushing for the preparation of asymmetrical cutting edges.
The "BrushtoCut" project comprised three modules in which brushing tools were designed, process knowledge was built up and a CAM module for path planning was developed.
In the project, innovative brushing tools for rounding the cutting edges of carbide cutting tools were developed and tested in use. The partner A+B Bürstentechnik produced brushing tools specific to the requirements and these were then used in trials at the Fraunhofer IPT for the rounding of cutting edges. Depending on the results, the tool concepts were iteratively optimized so that symmetrical as well as asymmetrical cutting edges could be specifically produced.
At the Fraunhofer IPT, the necessary process knowledge for the brushing process was researched in extensive investigations on a 5-axis tool grinding machine. Depending on the brushing tool and the set process parameters, the resulting material removal and the resulting geometry at the cutting edge were evaluated. In addition, experiments on brushing tool wear were carried out. Finally, a model was developed to predict the process outcome for the 5-axis brushing. The symmetrical and asymmetrical target geometries defined at the beginning of the project could be achieved.
In the project, a CAM module was developed that enables path planning for 5-axis brushing. The Fraunhofer IPT developed the definitions of the process parameters for this and provided further input for the implementation of the process strategy in the CAM system.
In a final benchmark, the brushing process was compared with laser machining, a manufacturing process that can also be used to specifically produce asymmetrical cutting edge geometries. Compared to laser machining, the machining time was reduced by more than 50%, thus more than doubling productivity.
The research project is funded by the German Federal Ministry of Education and Research (BMBF).
Publication on the project: Bergs, T., Schneider, S. A. M., Amara, M., & Ganser, P. (2020). Preparation of symmetrical and asymmetrical cutting edges on solid cutting tools using brushing tools with filament-integrated diamond grits. Procedia CIRP, 93, 873-878.