| As a kind of resistance welding and the result of the fast developing welding technology, flash butt welding is an effective way applied in many fields. With the development of computer and testing technology, the technics and the equipment of flash butt welding achieve a great deal of improvement in the following aspects, such as the control of the workpiece input, the way of the voltage control, the form of the electric wave, the collection of the data and the process control. For the parameter of flash butt welding is limited by many factors, the process parameter and control is difficult to standardize, especially for the manufacture and autocontrol of Hight-tensile steel chain (round link) flash butt welding machine which is a difficulty all the while. Therefore in the past years our country mainly depended on the foreign welding equipment.Model UNT400 of Hight-tebsile steel chain (round link) flash butt welding machine manufactured by Changchun coal science research institute is mainly used for mine Hight-tebsile steel chain (round link) jointing. The process of preheating flash butt welding is made up of three procedures—preheating, flash and withstanding . Therein preheating is processed before twisting instead of welding work funtion. According to the preconcerted procedures, the flash butt welding computer control system controls welding process both automatically and momentarily, while it also functions as information and consumers management.The corollary equipments of the system include of industrial computer, A/D, I/O, D/A, record display. The whole control process of welding is controlled by industrial computer and PLC.Main function of the computer control system:1. The process control of preheating flash butt welding computer sends out the signal to control flash melt, withstanding and other processes automatically through PCL. By this way it can complete the while welding control process.2. The real time monitoring and the record of flash current, displacement, withstanding pressure, water temperature, overheating of the motor; the data storage.3. The monitoring, diagnosis, and treatment of the possible failures information, which can ensure the security and the success of the whole welding process.A/D data collection that includes current, displacement, oil box pressure and so on, not only control, monitor the whole process, but also record the data. During the welding process I/O control system controls the hydraulic press valve of the hydraulic press system at different time according to the technics demand in order to achieve workpiece orientation and technology curve. The computer control system adopts the button opened of I/O relay to control the action of electromagnetic valve used to change direction like flash and withstanding, with the purpose of controlling the workpiece action. The most important process, process of flash and melt, introduces timing valve which can control the flux of the hydraulic pressure valve in order to control uniform motion of fixture and achieve flash curve required. All above measures help to control the input speed of workpiece in the flash process. By controlling changing-direction valve, it can change the diriection of the hydraulic press oil and consequently change movement direction of the workpiece. Once the problems appear, failure information testing I/O including water temperature, oil pressure would adopt the measures like turning off machine, giving an alarm and so on.Under Windows system environment, a special software for mining high strength circle-chain flash butt welding machine is programmed by using C++ and Access language. In the histroy of flash butt welding machine control, most of the controling system were progrmmed by PLC, which is considered as a ideal choice of this techincal control, for its simple operation, high efficiency and low system resources occupation. Furthermore, the solidified programme is faultless unless equipment loss occurs. However, these features restrict the expansion of PLC function as well. For example, the traditional PLC seems helpless in checking the parameter-timing graphs of displacement, pressure and electric cunrent dynamically; or recur the welding-process data of a certain time.Nowadays the computer technics has already stepped into an episode of the graphical interfaces, and it would be an easy describtion of the temporary graphs of various kinds of parameter under the graphical interfaces of Microsoft Windows Series. In addition, the popularization of advanced programming language like C++ and Java, the emergence of developing platform of VC and VB, as well as the development of database of SQLSever2000 and Access, all of these provide a conveniency for welding techs apply on PC. Under the environment of Windows XP system, by using Visual C++6.0 Developing Platform and Access Database, a sepicalized sol, ware system that integrates the control and management of large section workpiece flash butt welding machine is empoldered. This system implements a real-time obtain and a real-time inspect of every parameter in the welding process, meanwhile, it provides a dynamic description of the parameter-timing graph to convenient for controling. The system implements a data management and a seperation of operation purviews of its users to guarantee a reasonable utilize of the software as well as the security of data. The users can select the welding projects, establish the technical parameters, have a direct control of process, check the data informations, and analys the parameter graphs. That means, a workpiece -welding of different technics by using a singal welding system is possible. |
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