Tool–workpiece contact detection in micro-milling using wireless-aided accelerometer sensor

Abstract

Detection of tool–workpiece contact before the start of precision machining application is essential as it prevents tool breakage and aids in maintaining the accuracy of the machined workpiece. In this research, a wireless-aided three-axis accelerometer attached to a rotating micro-milling tool is used to detect tool–workpiece contact before the start of micro-milling operations. A three-axis accelerometer (ADXL345), an X-Bee pro wireless module and ATMEL328PP-U microcontroller along with other ancillaries were housed on a printed circuit board rigidly attached to a micro-milling tool using couplings. Subsequently, the micro-milling operation was conducted on three different materials, namely, aluminum, copper and brass, for three different revolutions per minute, depth of cut and feed velocity combinations. The accelerometer signals were received wirelessly in a personal computer. Impulsive change in accelerometer signal along Z-axis during machining indicated tool–workpiece contact. The depth of cut of the machined samples was measured using a profilometer. It was found that the setup was accurate in determining tool–workpiece contact at the start of micro-milling operations.