Defect detection for stamped part of hard disk shell

• Main Authors: TU, HSUN-CHENG, 涂勛城
• Other Authors: WANG, JING-WEIN
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/4xe9np

碩士 === 國立高雄應用科技大學 === 光電與通訊工程研究所 === 105 === Free edge is an important issue in sheet metal stamping as the stamping process affects burr appearance and thus influences product quality. In USB drive frame manufacturing, samples of cut frames are taken immediately after stamping and examined by human inspectors traditionally. However, human operators have several disadvantages compared to smart machines including subjectivity, productivity, consistency, and repeatability. Early defect detection is critical for reducing waste of raw material and achieving a high quality product. A great amount of time is therefore spent during the product development process on the optimization of stamping defects, particularly defect lows during tryout. By implementing such technologies in this thesis, the localized energy analysis with cross-projection is first adopted to capture the stamping region of component. Burr along the stamping region with thickness larger than 10 micrometers is classified with the proposed up and down ramping criterion. Then, the bilateral filter is applied to enhance regions with scratch and contamination. Energy analysis and cross-projection are also combined to detect the scratch and contamination regions by following with localized histogram analysis. Using samples taken from the local company based on Kaohsiung city, the experiments of stamping defects have been proved that the proposed framework well performed with 96.39 % recognition rate for the burr defects and 100 % recognition rate for the surface defects, respectively. The proposed framework is possessed of the advantage of autonomous detection with high recognition rate. Leveraging the unique integration of stamping on sheet metal with defect inspection has led to the development of new technologies that transform the performance of stamping press.