Digital Depth Inspection and Monitoring Based on CAT for Communication Technology

Transcription

1 2018 3rd International Conference on Automation, Mechanical and Electrical Engineering (AMEE 2018) ISBN: Digital Depth Inspection and Monitoring Based on CAT for Communication Technology Meng-qing TANLI *, Yan JIANG, Yu-lin WANG, Xiang WANG and Ru-shu PENG School of Mech. & Eng. University of South China, Hunan, Hengyang, China, *Corresponding author Keywords: Digital inspection, Quality monitoring, Measuring system. Abstract. This paper has deeply investigate the digital inspection and computer monitoring based on digital and CAT technology. Three main research aspects are discussed in detail for digital depth-inspection based on CAT, including: Digital inspection instrument, Communication interface of depth-inspection and Quality monitoring of depth-inspection result. In this approach, we fabricate a special apparatus with digital indicator depth meter, and monitoring software is developed by ourselves with visual c. Then, this paper has also put forwards a factual case with CAT measuring system, and results indicate that this depth digital inspection and monitoring approach is effective and convenient. Introduction As the main trend of quality inspection for manufacturing factory, digitalization has got great achievement, including display, interface output and computation processing, etc. because of the easy-to-use of inspection with instrument and the easiness of cooperation with computer processing, which eliminates manual error and decreases tiredness of manual labor. [1] Computer aided testing - CAT has got great progress with the developing of computer technology. Main points refer to three aspects in product quality testing: (a) computer application including data acquisition, digital display of inspection result and data processing of quality testing, farther more, digitalization of whole procedure of quality inspection with computer, (b) integration of quality inspection and result monitoring, (c) the visualization and intelligence of inspection results upon computer. [2-4] Computer monitoring of inspection results in product quality testing has also got great progress with the development of CAT technology. Based on CAT technology for measuring system, product quality monitoring with Shewhart chart can improve greatly efficiency and effectiveness. [2] With the development of advanced communication technology, interface communication, computer communication and data communication has become new research and developing point especially in measuring system, and more and more application are taken effect in quality inspection and monitoring.[5,6] Composite of Digital Depth Measuring System Generally, depth inspection is a usual inspection item in quality testing. It is magnificent and meaningful to adopt digital inspection technology in depth measuring system which efficiency and accuracy can be improved. Digital depth-inspection has been applied in measuring system of factual inspection of product quality for machining parts. Figure 1 is the composite of this measuring system based on CAT technology. In figure 1, Part of inspection implies the part of length-plus lift-bar, and Inspection apparatus is fabricated by ourselves. In this measuring system, digital indicator and data communication interface are all purchased from Shanghai measuring and cutting tool works. Computer is applied to data 584

2 processing and quality monitoring of inspection result, and printer is used to print inspection result and monitoring report. Part of inspection Inspection apparatus & Digital Indicator Data communication Computer Printer Figure 1. Composite diagram of digital depth measuring system. Main Research Aspects of Digital Depth-Inspection Based on CAT Digital Inspection Instrument Depth Meter [9-12] Digital inspection instrument, depth-meter, is a main aspect in this measuring system based on CAT technology. Regarding requirements of factual manufacturing factory, depth meter mainly includes: (a) Mechanical part of inspection, (b) Header of inspection-it can be dismountable from the apparatus. Mechanical Part of Depth-inspection testing Apparatus. Mechanical part of depth-meter mainly includes six sections: (a) Instrument base, (b) Back bar, (c) Installation beam, (d) Division pillar, (e) Supporting bench, (f) Operating setting. Detail is shown in figure 2. In this testing apparatus, supporting bench is used to place the part, i.e. length-plus lift-bar, and Installation beam is used to setup the digital indicator. Installation beam Operating setting Supporting bench Division pillar Back bar Instrument base Figure 2. Mechanical part of depth-inspection testing apparatus. Header of Depth-inspection Based on CAT. Header of depth-inspection in depth meter is an electronic digital indicator, which is manufactured in Shanghai measuring and cutting tool works. The measuring range of this digital indicator is 0-10 and the display accuracy is 0.01, but it must be taken attention that the actual indicating accuracy is 0.02 especially when the error analysis is computed. This digital indicator can be zero reset at any position which it is very convenient to apply in measuring of error. The factual object is shown in figure 3. Figure 3. Header of depth-inspection. Figure 4. Communication interface of depth-inspection. 585

3 Communication Interface of Depth-inspection [9, 10] Communication interface of depth-inspection is RS232C, which is usually applied in data communication between instruments and computers, the pins and profile of RS232C is shown in figure 4. RS232C has become the interface standard between data terminal equipment- DTE and data communication equipment- DCE, the connector of RS232C has two profile DB25 and DB9, and DB9 is usually applied in PC. The functions of individual line in DB9 are: 1-DCD implying DCE has received the transmitting signal and linked the communication route, 2-RXD receiving the serial data from DCE, 3-TXD submitting serial data to DCE, 4-DTR implying that DTE has prepared to submit when this signal is effective, 5-GND regarding as referring base of electric signal, 6-DSR implying that DCE has linked when this signal is effective, 7-RTS implying that DTE request to submit signal to DCE, 8-CTS as the responsible signal of DCE against RTS, 9-RI Notifying DTE that it has been called. Quality Monitoring of Depth-inspection Result [9-12] Quality monitoring is the main tool for assuring product quality, and to implement priority of monitoring for product manufacturing process, avoid to simple certification-test after finished machining. At present, quality monitoring is focused on statistical quality monitoring based on statistics and the main tool is the control chart. Shewhart chart is the main and very important tool of monitoring process quality in manufacturing factory. The principle of Shewhart chart is that probability of happening is 99.97% under normal distribution. In the mass and large batch production, median chart is a main monitoring tool. Control Limits of Median Chart Monitoring. According to principle of Shewhart chart, control limits of median chart monitoring are given by equation (1): UCL x A m R, CL x, 2 3 LCL x A2m 3R, where, UCL is the Up Control Limit, CL is the Center control Limit, and LCL is the Low Control Limit, and x is the average of sampling, and R is the maximum variance of sampling, and A 2, m 3 are coefficients of median control chart. Computer Implementation of Median Chart Monitoring Visual c is used to program this monitoring software. And the unified modeling language and tools are adapted to develop this software. The program flow diagram of median chart monitoring is shown in figure 5. (1) 586

4 start Setting coefficients Draw coordination Open text file Save the byte Save data transferred in array t Computing limits Drawing UCL, CL, LCL Drawing value line and texting out number Close file Transferring the byte to individual data All data is got No Yes End Figure 5. Programming flow diagram of monitoring. In the procedure of software implementation, we have taken care of following disposal: (a) distinguished districts in terms of information type; (b) to use familiar design controls for user; (c) median chart is placed on the above as general requirement. An actual running example is shown in figure 6, which inspection data is gathered from digital measuring system of length-plus lift-bar for drilling process. Figure 6. Analysis view of median chart monitoring. Figure 7. Running view of median chart monitoring. The inspection data of length-plus lift-bar is acquired using communication program of Shanghai measuring and cutting tool works. Inspection data is saved in data type of.txt. Then, inspection data are saved in array and continuously is generated and expressed as the type of median chart. There are 28 groups of inspection data, and sample volume of every group is four. In this example, there are four points of chart is beyond the control line. It illustrate that this data batch of sampling is out-of-control and the main cause is alternation of operator by process investigation, and we can set up a usual chart under normal control limits by deleting those unusual data to monitor the drilling process of parts. In case study, we will continuously analyze and discuss. Case Research depth-inspection of Length-plus Lift-bar Objected part of case research is length-plus lift-bar, and objected process is drilling process which parameter is Φ8-2(-0.25, +0.55). Although the part is manufactured under medium and small batch production, but drilling process can taken as a large batch production. Because there are 11 holes in every length-plus lift-bar, the batch quantity is magnified by 11 times. With this consideration, we use median control chart to monitor drilling process of length-plus lift-bar. 587

5 Measuring System of Depth-inspection and Monitoring Based on Computer Communication In order to inspection and monitor the machining quality of drilling process of length-plus lift-bar, a measuring system of digital depth-inspection and monitoring is set up which is shown in figure 7. This measuring system mainly includes two sections: inspection section and monitoring section. In inspection section, length-plus lift-bar is positioned at the seat of length-plus lift-bar, and the drilling depth of length-plus lift-bar is inspected at digital depth meter. And the inspection result is transmitted into computer below by RS232C interface, data has been shared for the upper computer and the lower computer across router, the monitoring software at the upper computer get inspection data from the lower computer and finfish monitoring of machining quality of drilling process of length-plus lift-bar. [13] Computation and Analysis of Inspection Data for Digital Depth-inspection As description above, by eliminate unusual data, 21 groups of inspection data are got with the measuring system, shown in figure 7, and the data results are shown in table 1. The volume of sampling is set with four, it is mainly considered for producing batch and the random of sampling. It easy to know, Variant value of drilling depth ranged from to 0.47 with average variety R =0.219, and mean of group x is equal to By computer processing with these inspection data as shown in table 1, limits of median chart are given in following equation (2). UCL 0.32, CL 0.14, LCL 0.02, (2) Router Printer Office of test director Digital depth inspection based on CAT technology Communication interface Results of Inspection and Monitoring Figure 8. Measuring system of digital depth-inspection. Figure 8 has shown the monitoring chart of drilling process of length-plus lift-bar. In this median chart, monitoring limits are given that UCL is 0.32, CL is 0.14, and LCL is -0.02, and supervising limits are given by 0.55 and The below indicating imply the monitoring state of every data group of median chart. With computer processing, it is easy to understand and avoid the difficulty of distinguish every point if it is beyond the UCL or LCL in the chart. In the above Figure 6, because UCL is equal to 0.32 and LCL is equal to-0.04, monitoring district of median chart is But monitoring district in figure 8 is 0.34, we can know that monitoring limits of Figure 8 is more rigid than that of Figure 6, it indicates that eliminating the unusual data will be tightened to quality control. As above, the caused of out-of-control for drilling process is alternation of operator, we suggest that applying NC machine tool to improve machining quality. 588

6 Table 1. Inspection data of digital depth-inspection x =0.149 R =0.219 Conclusions There are some good properties for digital depth inspection and monitoring based on CAT including advancement, easy-to-use and effectiveness. And the composite of depth measuring system based on CAT is reasonable. The application of digital measuring system indicates that this depth digital inspection and monitoring approach is effective and convenient. This measuring system is easy to be applied in depth-inspection and quality monitoring of cutting parts including length-plus lift-bar. With the analysis of factual case of length-plus lift-bar, setting-up new monitoring line by eliminating the unusual data is benefited and rigid to quality control. Moreover, because alternation of operator has increased machining error and decreased product quality, NC machine tool should been adopted to improve machining quality. Summarily, application of advanced technology such as digital meter, integrated measuring system, visualizing chart and computer processing technology can lift the grade of error inspection and quality control and improve working condition of product inspection. References [1] Shanghai measuring & cutting tool works, Product Specification, Shanghai, China, [2] Zhang Gongxu, New quality management, High education press, May, [3] Wu Liaoyuan, Research on intelligent quality & diagnosis technologies and the application in CIMS, 4, [4] Pu Zhaoban, Design of Measuring and Control Instrument, Beijing: 2014(In Chinese). [5] TanLi Mengqing, Jiang Yan, Wang Xiang,et al., Research on Quality Tests for Shop Floor Application Based on Local Network,International Conference on Automatic Control and Information Engineering ICACIE 2016, Oct ,2016, Hongkong, China. [6] TanLi Mengqing, Jiang Yan, Wang Yulin,et al., Research on integration of quality testing based on communication technology, 2016 International Conference on Computer Networks and Communication Technology CNCT 2016, December , 2016, China. [7] TanLi Mengqing, Development and simulated test of WEBSPC, IDDME &ACCSPI 2008, Beijing, Sept., [8] Zhao Haibin, Nabil Anwer, Pierre Bourdet, Wang Junying, Multi-sensor Integration for Coordinate Metrology, IDDME & ACCSPI 2008, Beijing, Sept., [9] TanLi Mengqing, Jiang Yan, Wang Xiang,et al., Research on global structure for digital quality testing based on manufacturing factory, nd International Conference on Electrical, Automation and Mechanical Engineering EAME 2017, April , 2017, Shanghai, China. 589

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