Monitoring of Long drill wear status through Vibration analysis using Time and Frequency domain

Hard carbon steel is used for drilling deep holes, such as C19, which has dimensions of 630 mm in length, 50 mm in breadth, and 125 mm in depth. Long twist drills with a diameter of 8 mm are used. Such drills are manufactured with larger helix than the traditional drills for increasing penetration efficiency. But, Prediction of long drill & tool replacement strategies during metal cutting are mostly depend on conservative estimation given by manufacturer's catalog. Hence, long drill while drilling cam shaft in automobile applications may be underutilized or over utilized. Now a day, Diagnostics software in advanced CNC machines are indicating hours of utilization of tools in bar chart. On the other hand, Utilization of long drill wear beyond the recommended range affects the quality of workpiece. As a result, several researchers have proposed the reliable approach of vibration-based online monitoring of drill flank wear over the past 20 years. In these works, the vibration sensor is mounted on the workpiece, allowing for good signal strength acquisition with little variation in distance from the drill holes and drill wear monitoring. The sensor cannot be placed in a fixed location that is equally spaced from all of the holes that need to be drilled for practically all workpiece profiles. In this project endeavor, the peck drilling technique utilizing vibration monitoring is proposed. The monitoring metrics of amplitude (N/m2) and frequency (Hz) are introduced through the examination of vibration in both the time and frequency domains. Experimental results show that percentage variation in long drill wear during severe wear and corresponding vibration signals of amplitude variation of long drill frequency is increasing five times than compared the vibration signals with other stages in the peak search method. This provides greater flexibility in replacement strategy of long drill through vibration analysis and higher percentage variation indicates that substantial to use for drilling.