2012 Volume 56 Issue 4 Pages 238-243
Measurement of the cutting force (thrust force and torque) by micro drilling is important to determine the cutting conditions. However, measurement of the torque is difficult and is associated with many technical problems. Therefore, the micro drilling machine was developed with the force sensor built-in spindle that measures cutting force simultaneously. The structure of the spindle used the air static pressure bearing to detect slight signal. The semiconductor strain gauge was used for detection of thrust power, and the optical sensor was used for detection of torque. The thrust force was less than 0.1 N and the torque was less than the detection sensitivity of 0.05 N･mm. The developed micro drilling machine monitors the maximum and minimum of cutting forces that were set up, and prevents breakage of a drill. In this way, machinability evaluation is possible using this micro drilling machine.
