| Along with the socialist market economy developing, the survival of the fittestbetween products intensified. Quality has become a key weight of producers in thecompetition. Traditional product quality detection relies mainly on manual inspection. Inview of the problems this method has low work efficiency, low accuracy and bad stability,machine vision inspection technology has been widely applied. Paper treats the middle plateof mobile phone as the research object. According to the nuts welding problems of middleplate, the special welding jig is designed. To complete the quality inspection task of middleplate, we put forward the application of machine vision detection technology combined withimage processing theory.Firstly we do a thorough theoretical study of visual inspection and image processingtechnology. According to several detection tasks of middle plate, the detection process isplanned rationally, and we design the overall structures of the visual inspection equipmentwith Pro-E, including the transmission, image acquisition mechanism, actuator etc. Thefunction and construction features of middle plate are introduced in this paper, and thedesign and use of assembled clamp for laser welding nuts of middle plate are discussed.Considering processing cycle, a new kind of nuts feeding fixture imitating the cartridge isdesigned on the basis. By analyzing the clamping state of middle plate with ANSYS, weachieve the stress and deformation. Treat center distance detection of welding nuts as anexample, we conduct a series of processing to the image of middle plate with Matlab.Including the weighted average method for gray image, median filtering to smooth noise,Otsu to perform binarization operation and Canny edge detection. Then we extract thecenters of middle plate welding nuts with the improved Hough transform method. Finallywe transform the pixel size of nuts center distance into space size with the systemcalibration parameter, and the result is compared with the value of manual measurement.According to using, the results show that nuts feeding fixture and nuts welding fixturefor middle plate of mobile phone are feasible and suitable for mass production. They can notonly guarantee the precision and quality of the nuts welding, but also shorten the wholeproduction cycle. The result of nuts center distance detection indicates that detectionaccuracy and speed of the visual inspection system can completely meet the requirements,and it can reduce intensity of labors and improve the production efficiency. At the same time, this two products will have very important engineering practical value. |
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