On-line wear detection of milling tools using a displacement fiber optic sensor

One of the major problems in precision machining processing can be related to the failure condition of the cutting tool. Hence online tool condition-monitoring is of much interest in metal-mechanics industry. The spontaneous problem of failure in a cutting tool, such as chipping and breakage, is becoming more and more important in the manufacturing technology and is usually associated with the stresses put on the tool during the cutting process. Other abnormal tool conditions in metal-machining includes: tool wear, tool-work piece, etc. In this work a method is presented for determining the wear and fracture of a cutting tool, by means of a fiber optic sensor with high resolution and large bandwidth, used during the manufacturing process. The sensor has been configured with two groups of fibers, distributed in a random fashion. One of the groups works as a light emitter that illuminates the tool, while the other captures the light reflected by the tool surface itself. The light is generated by a photodiode, which does not represent any risk to the health. This technique will allow observing the wear and breakage of the tool in real time while the tool is rotating, with a high degree of accuracy.