Analysis of interactions and effects of new preparation methods and resulting drill hole qualities in single lip deep hole drilling

• Applicant: Professor Dr.-Ing. Dirk Biermann
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2010 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 177322575

Single lip deep hole drilling is particularly characterized by the ability to produce a high bore hole quality, consequently by doing without subsequent machining procedures for quality improvement. Resulting bore hole quality is crucially based on the condition of the cutting part and its guidance elements within the bore hole. When applying single lip deep hole drills with insufficient surface qualities of the guiding pads as well as a progressive tool wear, failures and valleys in the external zone of the bore surface occur.The follow-up project will help to understand the tribological interactions between the cutting part and the bore hole surface during single lip deep hole drilling. The project objectives include the analysis of interdependencies of specific pre- and post-coating treatments with the performance of prepared drilling tools. Therefore targeted preparation applications are used for optimizing the surfaces of the guiding pads of single lip deep hole drills. The results of the research project benefits the development of tool preparation processes which leads to improved surface qualities. Beside an enhanced coating adhesion, a surface smoothing on prepared tools shall be achieved. In addition to the abrasive water jet blasting two further different high-precision surface treatments of another scope of application are going to be transferred. These will be polish-grinding and belt-finishing. Each of these kinematical different procedures guarantees high surface qualities and leads to an altered surface structure. The impact of respective pre- and post-coating treatments on surface texturization will be analyzed as well as the resulting shape and surface changings of the single lip deep hole drills. Drilling tests in tempered steel 42CrMo4+QT (AISI 4140) with lower sulphur content help to understand the interactions when applying prepared single lip deep hole drills and function for evaluation of the tool performance.

• DFG Programme: Research Grants