Root Cause of End Mill Cutting Tool Failure

摘要

The manufacturing industry prioritizes on fast production processes with low costs and high-quality products. One of the machines used in the production process is a milling machine. In the production process, failure often occurs, especially in a cutting tool which is components that are susceptible to failure. The HSS end mill tools were broken when used for the process of cutting on AISI A36 material. The milling machine works with 1.5 kW engine power, 640 rpm rotation, 5.1 ipm cutting speed, and 10 mm cutting depth. This research was conducted to examine the root cause of failure in end mill cutting tools. Failure analysis was carried out sequentially by investigating macro-microstructure, chemical composition testing and mechanical testing of microhardness. Scanning Electron Microscopy (SEM) observations showed that there were two parts of the fracture surface, which were fine and coarse surfaces. The coarse surface showed an intra-granular fracture. The chemical composition testing with energy dispersive spectrometry (EDS) found that rough surfaces lost the main elements of tungsten (W) and cobalt (Co). Both of these elements function to form double carbide which increases hardness and heat resistance. Vickers micro-hardness testing showed that fractures occur at high stress and low hardness concentrations. The surface with non-uniform grain size is the beginning of failure. Failure occurs due to defects in manufacturing processes that are not in the standard operating procedures.