Automatic Optical Defect Inspection and Dimension Measurement of Drill Bit

Abstract

A real time Automatic Optical Inspection (AOI) system for Printed Circuit Board (PCB) drill bit and the inspection methods are presented. After a brief comparison between traditional inspection methods and the AOI method, the outline of the AOI system configuration and inspection methods are described. Subsequently, the illumination method is discussed due to the special characteristics of drill bit blade for obtaining a clear and less distortion image. Based on the shape features of drill bit blade, inspection algorithms including edge extraction, edge subpixel location, line and curve fitting, corner detection and defect detection are investigated to enable inspection of 100% such drill bits including dimensional properties and surface defects for the drill bit blade. The test result demonstrates that the effectiveness of the developed inspection algorithms and the AOI method can meet the inspection requirements of PCB drill bits. Furthermore, AOI method makes the inspection for each drill bit available and increases the quality and the reliability of PCB drill bits.