Vision-based automated inspection system in computer integrated manufacturing

Abstract

The industrial application of an automated inspection system that aims to enhance the efficiency and flexibility of a computer integrated manufacturing system (CIMS) is proposed in this paper. A machine-vision-based approach is adopted to utilise its advantages of measurement flexibility, high resolution, and non-destruction. With a closed-loop feedback 1, IntroductionComputer integrated manufacturing (CIM) is widely accepted as a fundamental strategy employed for enterprises competing in the world market. The implementation of CIM systems, despite a considerable number of successful cases having been reported in many countries, remains a difficult task. A CIM system is typically a highly computerised system that consolidates all production and management functions in a company to form a more efficient unit, generally in an untended mode. The product quality and productivity can consequently be increased. In order to ensure a high quality product, it is essential to integrate an automated inspection system with manufacturing. Most current inspection systems achieve this quality control function by detecting deviations from specifications and relaying this information to a central computer. Fully automating the manufacturing system, however, requires that the inspection systems should possess the Correspondence and offprint requests to: Fei-Long Chert, Department of Industrial Engineering, National Tsing Hua University, Hsinchu, Taiwan, Republic of China. capability both to determine the possible causes of failures in manufacturing and to recommend solutions for these failures.The industrial application of an automated inspection system aimed to elevate the efficiency and flexibility of an automated manufacturing system is reported in this paper. A machinevision-based approach is adopted here which utilises its advantages of measurement flexibility, high resolution, and non-destruction. A closed-loop feedback control architecture is formed by fully integrating the inspection procedures with the production process. A defective part, once detected, is collected by a material handling device. An intelligent diagnostic algorithm based on statistics and heuristics is simultaneously applied to analyse the consecutive inspection results in order to deduce possible causes of defects. This system therefore not only eliminates defects but also recovers normal operations in a real-time mode.This proposed automated inspection system has been implemented on a physical shop floor for automatic inspection of wrench sockets of varied types and sizes. The machine vision system uses two cameras that perform multiple functions:1. The first camera recognises the shape of the socket, and measures its dimensions and concentricity. 2. The second camera determines the amount of die wear.This system, with other automated devices, assists in the formation of a truly automated manufacturing system. The experimental results show that the machine vision system has satisfactory performance and flexibility in the factory environment. Even thoug...

Defining Scanning Trajectory for on-Machine Inspection Using a Laser-Plane Scanner

“…Angles A and C are obtained from equation 2with the original vector V L and considering a constant value W cst . The adapted vector V C ' is thus simply computed thanks to equation (1). Finally, the adapted scan path respecting the control of overlap defined by (C E ; V L ; V C ' ) and the scanning simulation are shown in Figure 4.…”

“…In contrast, the adapted scan path with priority to scanning quality is carried out by keeping the director vector of the light-beam axis V C , and by calculating the adapted director vector of the digitizing line V L '. Angles A and C are calculated from the vector V C by equation (1). The adapted vector V L ' is then calculated by (2) with W = W cst .…”

“…Machining process monitoring is an essential challenge for the control of the quality of manufactured parts. To improve process productivity, part inspection procedures are increasingly integrated in the machining process as they allow high speed of inspection, measurement flexibility, and the possibility of 100% inspection [1]. Within this context, on-machine inspection becomes more and more popular as it allows a rapid decision-making with regards to part geometry conformity, and potential machining process corrections [2].…”

A novel approach for in-situ detection of machining defects

“…Inspection procedures are increasingly integrated in the machining process. Associated benefits include high speed of inspection, measurement flexibility, on-machine inspection, and the possibility of 100% inspection [3]. In the context of integrated inspection, three types of measurement can be differentiated: in-situ measurement, in-process measurement, and onmachine measurement [18].…”

“…Whatever the sensor used, in-situ measurement enables rapid decision making regarding the part's geometrical conformity, as the measurement stage is performed during the manufacturing phase. A direct link exists between Computed-Aided Inspection (CAI) and Computer-Aided Manufacturing (CAM), which can lead to a complete integrated manufacturing process [3]. However, a high level of integration requires the process planning to be changed in order to adapt to the specificity of in-situ measurements.…”