Development of an automatic optical inspection system for defect detection of dental floss picks

This study aims to make improvements in manufacturing yields for dental floss picks, through deploying automated quality inspection processes. By using computerized visual inspection and automatic controls, this study explores standardization and automation of inspection work for the three major defects affecting dental floss picks and dental floss fibers. Among the industrial design solutions implemented by this study are environmentally efficacious layout of light sources, optimal configuration of optical imaging and automated equipment, and the design and development of a proprietary defect detection program; moreover, an automatic optical inspection (AOI) system, which can be installed in the production lines, is built for verification. As for verification of detected defects, trial operations can be conducted on production lines and adjusted to optimal parameters in order to measure floss fiber defects with an area larger than 0.09mm², impurity defects with gray-scale difference greater than 35, and shortage defects with lengths greater than 3mm. Statistical analysis of practical measurement results on ten dental floss picks indicated system detection rates of 93.1% for floss fiber defects, 56.2% for impurity defects and 84.4% for shortage defects.