Development of an Automatic Optical Inspection System for Wire Torsion Springs

• Main Authors: Jia-hua Jhang, 張嘉華
• Other Authors: Geo-Ry Tang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/40413339044323872473

碩士 === 國立臺灣科技大學 === 機械工程系 === 102 === This study aims at the development of an automatic optical inspection system for wire torsion springs. Including motion module, image module, classification module, electrical control module and human-machine interface together, the inspection system can measure dimensions of springs and identify defective products. A toolmaker’s microscope has been selected to provide the true dimensions of sample springs, after the gage repeatability and reproducibility proved its reliability. From a preliminary study, it was found that the orientation of a spring could affect the dimensions measured from its image. This research establishes a good criterion to distinguish upward spring from downward springs. Statistics such as means and variances obtained from testing data are used to search for a threshold, which will be used to determine the existence of a cutting mark on the spring images. After proper calibration procedures, the inspection machine can get the images and measure the dimensions of the springs on the conveyor. Based on the design specifications, the system can separate good products from defective products automatically. The machine also shows an accuracy of 99% while inspecting 240 pieces of springs per minute.