Automatic optical flank wear measurement of microdrills using level set for cutting plane segmentation

We address the problem of automatic optical flank wear measurement for microdrill bits’ inspection. Cutting plane segmentation of microdrill bits is a fundamental step in the measurement. However, in the case of smeared microdrill bits, cutting planes cannot be segmented correctly by conventional methods. To exactly extract the cutting plane, a level set technique is proposed to segment it from a drill bit image; then we adopt a projection profile-based method for measuring the features of flank wear of microdrills. A new feature of flank wear, called “end wear length”, is also introduced for flank wear evaluation with three other existing features. Experimental results indicate that it is a robust and effective approach for automatic flank wear measurement of microdrills in printed circuit board (PCB) manufacturing.