Development of tribological optimized guide pads for deep hole drilling processes

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Within the actual transfer project the achieved results and the knowledge of the tribological optimization of guide pads for deep hole drills will be applied to alternative deep hole drilling processes. In the fundamental project a new process chain for the development of guide pads for the BTA deep hole drilling process has been realized. This process chain includes the application of a friction reducing ta-C-Coating as well as pre- and after-treatment of the uncoated and coated substrate. The conventional polishing process has been substituted by microfinishing. The latter effects a defined shape optimization of the axial lead-in-area when finishing the uncoated substrate. The finishing as an post-treatment is responsible for an effective removal of the droplets. The wear behavior of the modified guide pads is significantly better than the wear behavior of conventional pads. The optimization of the shape with respect to the finish process to adjust the guide pad geometry has been adequately studied, resulting in an optimized solution. In combination with the ta-C coating, a guide pad design has been invented which improves the tribological contact conditions between the guide pad and the bore wall. In the proposed project the findings will be extended to other drilling processes. Here, the shape optimization by microfinishing will be investigated with regard to the efficiency of the application of other coatings. Additionally, the use of a ta-C coating for the guide pads of gun drills will be analyzed. Based on the results of the fundamental project and the newly developed solutions, a final application of the modified drilling tools in industrial drilling processes will be carried out.