Research And Implementation Of The Electron Beam Welding Machine Control System

With the development of industrial technology, electron beam welding technology has been widely used in various fields, especially in high-precision welding occasions. The domestic CNC systems which used in the electron beam welder are special and closed systems, and most of them are expensive and difficult to extend. In order to meet the special requirements of the welding seam, the key technical issues of the motion trajectory changing with the welding energy in real-time synchronization need to be solved, in the process of high quality requirements for welding. This thesis has developed a good scalability and low cost open CNC system of the electron beam welder by the design of the hardware and the development of the software. This system has achieved the unified programming and synchronization control between the moving trajectory and welding energy provided, so as to improve the welding efficiency and accuracy.First of all, this thesis introduces the current development of the electron beam welder, the research dynamic and application status of open CNC system both at home and abroad. The design scheme of the control system of the electronic beam welding machine is set up based on analyzing and comparing the current popular design scheme of the open CNC system, and the actual situation and the requirements of this thesis.In the hardware design, this thesis divides the hardware system of the electron beam welder into three control systems, according to the design scheme. The three control systems include: the power supply control system, the vacuum control system and the motion control system. And the function and type selection of each system is introduced in detail. The hardware of the whole control system takes industrial control computer as the core, makes PLC and the motion control card through serial port and PCI bus to complete tasks such as task allocation, data calculation and so on.In the software design, the software system is divided into the upper computer software and the lower computer software. The upper computer software includes the man-machine interface module, the NC instruction code compilation module, the trajectory interpolation module, the process control module, the fault diagnosis module and the status display module. The lower computer software includes the vacuum system control module, the power system control module, the servo control module and the motion board drive module. In addition, the catch statements have been added into the upper computer software to find the cause of the error and suggest modifications when the G code is read or the software is crashed; in the lower computer software, the watchdog program is enabled, software state can be monitored, and when the program run or fly into an infinite loop, the software will reset.Finally, this thesis introduces the three factors of the electromagnetic interference: the interference source, the coupling path and the sensitive equipment, and analyzes the interference source of electron beam welder to the control system. Therefore, the isolation transformer and the noise filter is added in the power of the servo controller, the molecular pump and other precision equipment. And their connecting cables are shielded, to make sure the whole control system working normally, under the influence of surge, harmonic and electromagnetic interference to the control system power supply when the electron beam welder start or stop.