Tool holder sensor design for measuring the cutting force in CNC turning machines

Cutting force is of great importance in turning processes because several characteristics of cutting force are useful for predicting and detecting tool conditions such as tool wear and tool breakage. Many commercial devices have been developed to precisely measure cutting forces; however, they are expensive and some installation limitations could limit their applicability in real applications. The cutting force should be measured using a simple, compact, and low cost technique. The present work covers the design and construction of a tool holder sensor to measure the cutting force generated by a CNC turning machine during a turning process. Strain gauges are attached directly inside the tool holder sensor, one on each side of the rectangular shank, to measure strain and estimate the cutting force. Several machining tests performed on a CNC turning machine showed that the proposed tool holder sensor design successfully and precisely measures cutting forces with different turning conditions.