Development and testing of a wireless multi-axis toolholder dynamometer for milling and drilling process

The cutting force provides important information such as tool condition, chips information, and machining parameters selection. Thus, many researchers have proposed some methods for cutting force monitoring. However, most of them are only applied in the laboratory due to lower flexibility and complex installation. In this paper, a split multi-axis toolholder dynamometer is proposed and developed, which can equip different types of machining spindle and fit for multi-size tool. It consists of six capacitive sensors that can sense four deformations in vertical direction and two deformations in circumferential direction. Meanwhile, the distance between two plates in the vertical and circumferential capacitive sensors was adjusted separately. An acquisition and wireless transmission unit was designed to detect the capacitive variation and then transfer data to upper computer. Finally, a standard tool holder and a force sensing unit, a bottom socket, an acquisition and wireless transmission unit, a lithium battery, a cover were installed and debugged as a whole system. To validate its static and dynamic characteristics, various tests are conducted. The result demonstrates that the toolholder dynamometer can accurately and reliably monitor four-axis cutting force in the milling and drilling operations.