Research On Key Technology Of Large Welding Parts Producing System For Construction Machinery

Loader is widely used for construction machinery, and plays an important role in the national economic development. Currently, the loader's marketing competition is very serious, and its production competition tends to be more international. Loader is widely used in our country, but compared with the other countries, there lays a great backlog in respects of quality, reliability and so on. The barriers which restrict our loader development mainly include welding equipment organization, the welding parts producing efficiency and quality control. In view of the long-term planning and developing requirements of the enterprise, we carried out important research focusing on key issues, i.e., direct influence of welding machining quality and efficiency in the production of large welding parts for Construction Machinery: the technology analysis of large welding parts, the workshop equipment layout and logistics analysis, the residual distortion forecast and control of large welding parts, the welding fixture system structure design of large welding parts and its relevant technology research. The main study content is as follows:An optimized computing model of the welding equipment layout and a producing model of welding production line have been set up. (1) To begin with the workshop producing objects technology, the machining time of every process, the equipment layout and its logistics moving, one computing model based on workshop equipment has been built up. And according to the technology, we re-distinguished the technology, ascertained the amount of equipment, planned the workshop preliminary, determined the format of producing cells. (2) We ascertained the producing scale of the welding production line, designed the equipment layout according to the beat balance principle and the least logistic moving principle, simulated the welding production line with EM Plant, validated its rationality by contrasting the logistic moving deference between the traditional one and the optimized one.The welding hot stress and distortion model of great welding part has been setup, and the distortion and hot stress of the part have also been analyzed. (1) The welding capability of great welding part material has been analyzed; the distortion and stress of the welding part has been analyzed and simulated by finite element method. (2) The whole welding part distortion model has been setup, and the law of distortion has been found out so as to forecast by ABAQUS software, the data accords with real distortion, the measures reducing distortion has been put forward, It has also been raised to take measures improving the structure with studying great welding part loading force and invalidation type.Building framework type clamping and locating system for wielding fixture has been set. (1) The model of process function of the fixture design has been analyzed. (2) By discussing large numbers of advanced fixture design methods, the concept of building framework has been set up based on Group Technology fixture adjusting and exchanging and the concept of flexible fixture. (3) The clamping and locating system of welding fixture layout is made reasonable according to analysing welding distortion and hot stress so as to reduce the distortion of the welding parts and improve precision.