dynoSpan - Investigation of the dynamic behavior of CFRP single-lip drills with internal chip channel

• Applicants: Professor Dr.-Ing. Dirk Biermann; Dr.-Ing. Carsten Schmidt
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 581072147

From the production of molds for various primary forming processes to applications in medical technology and the food industry - deep hole drilling is used in a variety of industrial sectors, especially where holes with a high length-to-diameter ratio are required. With the increasing complexity of both the systems and the individual components in various branches of industry, the demands on the corresponding manufacturing processes are also increasing. Deep hole drilling therefore represents a particular challenge in the field of modern machining technology. Depending on the bore hole diameter, different deep hole drilling processes are used. While BTA deep hole drilling (Boring and Trepanning Association - BTA) is used for larger diameters in the range of 6 mm to 1500 mm on special machines, the single-lip drilling process, preferably for particularly small diameters of around 0.8 mm to 40 mm, can also be used on conventional machining centers. Due to their considerable length-to-diameter ratio, these deep hole drilling tools are particularly susceptible to vibrations. These vibrations, caused by the low dynamic torsional and bending stiffness, manifest themselves in chatter marks at the bottom of the bore hole and on the bore hole wall. The resulting high thermal and mechanical loads in the contact zone between the tool and workpiece can have a negative impact on the subsurface properties of the bore hole and promote premature wear of cutting edges and guide pads. The aim of the research project is to develop and investigate a new type of tool concept for the single-lip drilling process (ELB). This concept is designed to work without additional mechanical and hydraulic vibration dampers. Instead, the use of carbon fiber composite materials for the tool shank in conjunction with 3D-printed drill heads is intended to significantly reduce undesirable torsional and bending vibrations along the entire drill. In addition, it is planned to gain important insights into the application and fatigue behaviour of this material combination and its interaction with hybridization process parameters in order to improve the efficiency and reliability of the single-lip deep hole drilling process and thus contribute to its further development.

• DFG Programme: Research Grants