Study Of Repairing Screw Thread Technology Based On Open NC System

CNC machine is an essential material means to improve the quality of product and the productivity. Reconstruction of machine by using CNC system, which has the characters of low cost and short period, is an efficient means to restitute the machine, meanwhile, it can reinforce the old technology index. This means promotes the progress of the manufactory industry, which is adapted to the circumstance of our country. Currently, according to the urgent need of the NC machining technology, which repairs the thread groove of the screwed workpieces in oil industry, it is very important to study the technology of repairing screw thread.Based on studying numerical control technology about development general situation of abroad and home in this thesis, the necessity of building Open NC system is put forward. Through analyzing the problem of position-setting for the thread workpiece on the standard NC lathe in the theory, the workpiece is determined to be fixed without precise position-setting in both axial direction and circumferential direction, the screwer is adjusted by one thread groove. The finding position algorithm for the screw workpiece and the thread trace is applied, then the position of the workpiece and the screw track are located exactly in the workpiece coordinate system. With the NC system which integrates the personal computer and the movement controller, the simple NC system of CAK6150 lathe is improved to NC system of integrating the Open NC system and closed-loop control method. To build Open NC system includes configuration design of software and hardware. High speed position capture function of the movement controller and the feedback signal of the photoelectric encoder which is synchronizing with main axle absolutely are applied, the offset between the actual starting point and the thread groove starting point is compensated. The theory of repairing screw thread technology is applied on the improved lathe. The continuously function of resumption thread cutting is achieved and the trace disorder problem is solved. Furthermore, the auto-program and dynamic emulation software is designed. The software includes main control softwaremodule, repairing parameters input module, numerical control code build module and repairing screw emulation module. In this software, as long as the key parameters are inputted, the NC program will be created out immediately, and the dynamic emulation will be accomplished to check up the validity of the NC program.It shows that the reconstructed system has high reliability, steady capability and friendly interface. The productive efficiency is improved, and the anticipant target is achieved.