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1.INTRODUCTIONCompared with the steel casing made of traditional materials, the aluminum-magnesium casing has the characteristics of small proportion, high strength, high corrosion resistance, complex structure and integrated design, and is generally used in the front deceleration, air intake, accessory transmission and other components of aero-engine1. The aluminum-magnesium casing has the characteristics of processing technology such as large machining allowance, difficult material processing, complex part shape, complex processing technology2, and its processing quality is affected by many aspects such as tool performance and material, processing equipment, process parameters, and process route arrangement. Due to the various types of Al-Mg casing parts, small processing batches, long production cycle of a single product3, and limited by casing processing technology, processing equipment and other factors, the production process of the traditional casing manufacturing workshop is relatively complex. At present, there are many problems in the traditional casing manufacturing workshop of Enterprise N, such as slow line changing speed, insufficient personnel, low utilization rate of processing equipment and high failure rate, and low fault tolerance of abnormal events. Therefore, the processing of aluminum magnesium casing parts urgently needs an efficient processing flow and information integration management processing mode to solve the above problems. 2.OVERALL DESIGN OF FMC FOR ALUMINUM MAGNESIUM CASING2.1Design of flexible manufacturing cell body of aluminum-magnesium casingThe flexible manufacturing unit of aluminum magnesium casing mainly includes processing system and logistics system4. The machining system mainly includes a machining unit and a central tool magazine composed of a CNC lathe and a five-axis machining center. CNC lathe and machining center are mainly responsible for the processing of aluminum magnesium casing parts. The selection of machining center is the basis of flexible manufacturing of aluminum magnesium casing. The central tool magazine is one of the key technologies for efficient machining of aluminum-magnesium casing. Before and during the whole machining process of aluminum-magnesium casing parts, the central tool magazine configures the tools needed for aluminum-magnesium casing machining according to the instructions issued by the production management system. The tool transport robot transports the tool from the central tool magazine to the machining equipment in advance, reducing the tool change time and improving the machining efficiency. The logistics system mainly includes loading and unloading station, tool transport robot, pallet warehouse, material transport robot and guide rail. The exchange of pallets between processing equipment, loading and unloading stations and pallet warehouses is completed by the material transportation robot; the transportation of the tool between the machining equipment and the central tool magazine depends on the tool transport robot. The logistics system is equipped with a console, which can be controlled by the operator to complete the operation of pallet transfer, loading and unloading of pallet warehouse. The body design of the aluminum-magnesium casing flexible manufacturing unit is shown in Figure 1. 2.2Process flow design of flexible manufacturing cell for aluminum-magnesium casingBased on the above design of the flexible manufacturing unit of aluminum-magnesium casing, the processing flow design of aluminum-magnesium casing unit manufacturing is completed according to the processing technology of aluminum-magnesium casing parts. The processing flow is as follows :
2.3Determine FMC stationBefore selecting equipment, it is necessary to calculate the cell production rhythm to determine the number of production equipment in the cell5. The calculation formula of production rate is: According to the requirements of the production task provided by Enterprise N, the annual output of the flexible manufacturing cell of aluminum magnesium casing after being put into production should not be less than 900 pieces, and the qualification rate is 85%. The cell works six days a week, and the cell is produced in two shifts, that is, 16 hours a day. Assumed equipment efficiency: ηmi = 100%, flexible cell utilization: ηu = 100%. Bring the data into Formula 1 to calculate the production beat time: In the flexible manufacturing cell of aluminum magnesium casing studied in this paper, due to the technological characteristics of aluminum magnesium casing, a machining center can complete multiple processes, that is, a machining center is a station, and the station design is completed, that is, the number of machining centers responsible for workpiece processing in the cell is determined. In order to ensure the continuous movement of the workpiece between the machining centers, the number of machining centers should be equal to the ratio of the total operation time to the cell production beat time. The calculation formula for the number of cell equipment is shown in Formula 2: According to the calculation of the process duration of the Al-Mg casing parts to be processed by the cell, we select the total process duration of the starter casing with the longest processing duration among the four Al-Mg casing parts to be processed, and calculate: Rounded up, the number of cell equipment is m=4, so a total of 4 machining centers are required in the manufacturing cell to complete the processing of aluminum magnesium casing parts. Generally, the equipment load factor K is used to evaluate the rationality of the cell equipment quantity. The equipment load factor is an evaluation index of the equipment usage. It is generally believed that if K is greater than 0.75, the cell can carry out continuous production and the quantity setting is reasonable; If K is lower than 0.75, it is considered that the equipment quantity setting is unreasonable, and intermittent production should be adopted. The calculation result of equipment load factor of this cell is: According to the calculation results, the manufacturing cell rhythm and the number of processing equipment designed in this paper are reasonable. In the manufacturing unit of aluminum-magnesium casing, the processing equipment determined by the processing technology of aluminum-magnesium casing itself shall be removed, and the operation platform, cleaning machine and loading and unloading station shall also be included. In order to reduce the floor area, the central tool magazine and tool transport manipulator in this unit adopt truss structure and are arranged above the machine tool, so they do not occupy the station. To sum up, 7 stations are required in this unit, consisting of 4 processing equipment, 1 loading and unloading station, 1 cleaning station and 1 operation platform. 2.4Equipment selection of FMC
3.LAYOUT DESIGN OF FMC FOR ALUMINUM MAGNESIUM CASING3.1Establishment of mathematical model
3.2TS algorithm design for linear layout of cell
3.3Model solvingAccording to the logistics volume of the parts provided by the enterprise between the equipment, the handling cost between the equipment, the size of the equipment in the cell and the minimum safe distance matrix between the equipment9, as well as the mathematical model established above, the tabu search algorithm is used to solve the problem. First, use the insertion method to find the initial solution through the equipment number, and use MATLAB 2020a as the tool to program, set the tabu length:T=7, and the maximum number of iterations:I=200。After calculation, the algorithm calculates the best objective function value at the 54th iteration as E=22693, that is, the minimum maximum logistics cost is 22693. The optimal layout of the equipment is P=[7, 5, 2, 3, 4, 1, 6]. 4.RESULTAccording to the solution results, the position of each processing equipment can be determined preliminarily. According to the results of the field survey, combined with the minimum safety distance between the equipment and other information, the actual layout of the flexible manufacturing cell of the aluminum magnesium casing is determined, and the cell layout is shown in Figure 2. The flexible manufacturing cell of aluminum magnesium casing completed in this paper is composed of two turn-milling composite machining centers, two horizontal five-axis machining centers, one automatic loading and unloading logistics system (including material transportation robot, material warehouse, loading and unloading station), one set of tool magazine system (including tool loading and unloading station, central tool magazine and tool transportation manipulator) and production management system, which can realize the mass processing and manufacturing of aluminum magnesium casing parts, and the cell covers an area of 32m × 10m, (6m high) about 320 square meters. 5.CONCLUSIONThe construction of the flexible manufacturing cell for aluminum magnesium casing has realized the mixed production of multiple types and multiple processes of the casing parts, which can effectively improve the production efficiency and the controllability of the production process10; At the same time, the machining quality of aluminum magnesium casing parts is improved. The flexible manufacturing cell of aluminum magnesium case is an important research direction for traditional case manufacturing workshop to move towards automation, digitalization and intelligence, and has great significance for promoting the transformation of traditional case manufacturing workshop to digital workshop. ACKNOWLEDGMENTSThis work was supported by the Ministry of Education in China Project of Humanities and Social Sciences under Grant (17YJC630139), Natural Science Research Project of Higher Education Institutions of Jiangsu Province, (No.21KJD460003) and Taizhou Science and Technology Support Plan (Social Development) Project (No.SSF20210002). REFERENCESLi, L. J.,
“Technical features of precision machining of aluminum-magnesium casing [J],”
Commodity and Quality, 229
(23),
(2018). https://doi.org/10.3969/j.issn.1006-656X.2018.23.219 Google Scholar
Deng, Y. S., Hu, Z. X., Leng, H. B., Zhu, C. X.,
“Application of efficient composite processing technology for aluminum magnesium casing of aeroengine [J],”
Metal Processing (Cold Working), 10 13
–17
(2022). Google Scholar
“Research on improvement of machining process of front bearing casing of an aeroengine [D],”
Dalian University of Technology,
(2020). https://doi.org/10.26991/d.cnki.gdlu.2020.000198 Google Scholar
Shu, N.,
“Research and Application of Flexible Manufacturing Cell for Turbine Manufacturing Enterprises [D],”
Nanchang University,
(2021). https://doi.org/10.27232/d.cnki.gnchu.2021.003132 Google Scholar
“Efficiency evaluation and predictive maintenance of key equipment of engine casing production line [D],”
Nanjing University of Technology,
(2021). https://doi.org/10.27241/d.cnki.gnjgu.2021.001093 Google Scholar
Fang, J. J.,
“Research on facility layout optimization of manufacturing cell [D],”
Hangzhou University of Electronic Science and Technology,
(2017). Google Scholar
Long, G. J., Lin, B. H., Cai, H. X., Nong, G. Z.,
“Developing an Artificial Intelligence (AI) Management System to Improve Product Quality and Production Efficiency in Furniture Manufacture[J],”
Procedia Computer Science, 166
(C), 486
–490
(2020). https://doi.org/10.1016/j.procs.2020.02.060 Google Scholar
Fu, Y. X.,
“SMT production management system based on RFID research [D],”
Guilin university of electronic science and technology,
(2021). https://doi.org/10.27049/,dcnki.GGLDC.2021.001008 Google Scholar
Zhong, W.,
“For small discrete manufacturing enterprise production process management system research and development [D],”
Nanchang university,
(2021). https://doi.org/10.27232/,dcnki.Gnchu.2021.003128 Google Scholar
Liu, H. Y.,
“Some air products manufacturing workshop production scheduling intelligent management system research [D],”
Harbin industrial university,
(2021). https://doi.org/10.27061/,dcnki.Ghgdu.2021.002558 Google Scholar
|