The Development Of Automatic Welding Machine For Pin Tube

As a heat-exchange equipment of tube-type heating-furnace in petrochemical industry, pin tube mainly is used for thermal energy convert, and its efficiency is higher than finned tube exchanger, besides tending to clear, however, production of pin tube is very complex. Recently, there are a lot of processing methods. The traditional manufacturing method of pin tube, which pin is loaded by manual and welded by ordinary welding gun, with heavy labor intensity, low productivity, high energy consumption and unstable welding quality, can not adapt to the requirement of modern manufacturing. Therefore it is clear that research on the technology of pin tube automatic welding is of great significance.Advantages and disadvantages of current machine methods of pin tube are analyzed sufficiently; submerged-arc stud welding is chose as welding method of pin tube. According to automatic machining procedure and needs of pin tube, and with the consideration of realistic manufacturing technology of factory, an automatic welding machine for pin tube is designed. The over-all structure design of automatic welding machine including mechanically-driven device, clamp system, automatic feeding and alignment system, welding head with double cylinder coordinated type and flux conveying mechanism. Meeting all kinds of working conditions and forms of pneumatic actuators in the machine, a simple and reliable pneumatic circuit is put forward. Parameters and specifications of pneumatic components are calculated based on different load and needed velocity. On control, using PLC as the main controlling equipment, hardware of system including composition, operating principle and main circuit diagram are designed. On software, whole structure and compose of procedure are designed, and main function of every program is put forward. In addition, a high-accuracy control system including angle and displacement which are consisted of PLC, AC servo motor and photoelectric encoder is provided.The problem of half machinery, half manual operation way, low efficiency, unstable quality and few specification of the tradition auto pin tube machine are solved in this thesis. The experimental results show that this equipment can improve welding efficiency and quality greatly and overcome welding flaw including flash, inclusion and void etc compared with manual welding.