Acoustic Monitoring of Machine Tool Health Using Transmitted Sound

Tool condition monitoring systems (TCMS) have approached detection of tool wear over time from several perspectives: visual inspection, vibrational analysis, acoustic emission, power consumption and sound analysis. Current research focuses on monitoring methods involving expensive and complex sensor systems placed in close proximity to the machining operation itself. Understandably, industry has been slow to adopt these methods due to the initial high cost of sensors and the risk of damage to those sensors in the industrial environment. Methods that can monitor industrial machining processes from more remote locations would allow protection of valuable sensor systems and involve simpler installations. Researchers have established a significant relationship between tool wear and the sound signature of machine tools, yet there has been little work in developing this into a workable application. Issues encountered by researchers focus mainly on separating background noise from the noise of the tool itself, and methods to automate the recognition of tool wear conditions in sound signatures. This paper reviews the current state of research in the sound monitoring of tool condition in machine shops.