This is a further development work on grouping of printed circuit boards(PCBs)for Surface Mount Assembly in the electronic industry.The arrangement of PCBs among several surface mount machine lines is a typical kind o...This is a further development work on grouping of printed circuit boards(PCBs)for Surface Mount Assembly in the electronic industry.The arrangement of PCBs among several surface mount machine lines is a typical kind of group technology(GT)problem.From literatures,there are various clustering techniques developed to solve the clustering problems.In this paper,fuzzy c-means clustering(FCM)is used to solve the PCBs grouping problem.Applying them in a real problem compares the results of the two methods.The result shows that there should be a systematic method to arrange the scheduling of PCB assemblies in electronic industry to improve the operations planning process.展开更多
With the increasing miniaturisation and integration of electronic products and the increase of heat, it is necessary to design and introduce heat sinks and install fans. The volume of electronic components, especially...With the increasing miniaturisation and integration of electronic products and the increase of heat, it is necessary to design and introduce heat sinks and install fans. The volume of electronic components, especially the height, is very important for the structural and thermal design of electronic devices. This paper presents a design scheme of an online height measurement device based on laser triangulation and commercial charge coupled device(CCD). It analyzes the principles of electronic component height measurement, and expounds the composition and working principle of the laser measurement system. In addition, the commonly used methods to determine the center position are compared and analysed. These methods include circle fitting, gray centroid and extension method or Gaussian fitting. These methods usually lead to different results. The experimental results show that the fitting speed of the gray centroid is faster. The 3 D model of components is given through measurement, and the error factors affecting measurement are analysed.展开更多
文摘This is a further development work on grouping of printed circuit boards(PCBs)for Surface Mount Assembly in the electronic industry.The arrangement of PCBs among several surface mount machine lines is a typical kind of group technology(GT)problem.From literatures,there are various clustering techniques developed to solve the clustering problems.In this paper,fuzzy c-means clustering(FCM)is used to solve the PCBs grouping problem.Applying them in a real problem compares the results of the two methods.The result shows that there should be a systematic method to arrange the scheduling of PCB assemblies in electronic industry to improve the operations planning process.
文摘With the increasing miniaturisation and integration of electronic products and the increase of heat, it is necessary to design and introduce heat sinks and install fans. The volume of electronic components, especially the height, is very important for the structural and thermal design of electronic devices. This paper presents a design scheme of an online height measurement device based on laser triangulation and commercial charge coupled device(CCD). It analyzes the principles of electronic component height measurement, and expounds the composition and working principle of the laser measurement system. In addition, the commonly used methods to determine the center position are compared and analysed. These methods include circle fitting, gray centroid and extension method or Gaussian fitting. These methods usually lead to different results. The experimental results show that the fitting speed of the gray centroid is faster. The 3 D model of components is given through measurement, and the error factors affecting measurement are analysed.
