Development of a tool-side telemetric dynamometer for measuring mechanical loads during single-lip deep hole drilling

Abstract Single-lip deep hole drilling is used to produce deep holes in a diameter range of D = 0.5…80 mm with a length-to-diameter ratio of l / D ≥ 10. The deep hole drilling process is used in industry, for example, in the production of internal cooling bores in aerospace engines and in the production of implants or surgical instruments for medical engineering. The analysis of the deep hole drilling process is crucial to optimize the performance and durability of drilling tools and the quality of the machined components. In this context, precise and reliable measurements of the torque and the axial load are decisive. These characteristics provide information on the mechanical load on the cutting tool, its state of wear, and the efficiency of the deep hole drilling process. Off-center holes in a workpiece pose a particular challenge for force measurement on the workpiece side during the process and require a more complex tool-side application of sensor technology. Conventional commercial measurement technology is unsuitable for large cutting tool diameters due to the comparatively high axial forces and bore moments, so a dynamometer had to be developed that could withstand the mechanical loads and fulfill the measurement requirements. Further requirements for the development of a dynamometer are, in addition to the wireless transmission of the process characteristics, the preservation of the machine functionalities. In particular, the coolant supply is necessary for safe processing and the removal of chips from the cutting zone. The design of the measurement system is described, and the results are compared with conventional systems in the sigle-lip deep hole drilling process. The developed system enables tool-side measurement of the process parameters feed force and torque. The advantages of tool-side measurement of process parameters are explained and clearly demonstrated in the results when compared to conventional measurement technology at the workpiece-side.