Key Technology Of Spatial Curved Surface Intelligent CNC System In WEDM-HS

Nowadays, so many moulds in machining Electronic device, Instrument, Motor, Airplane and Missile should have blanking taper or different shapes between up and down section view. The technique that processes spatial curved surface (SCS) in Wire Electronic Discharge Machining with High Speed (WEDM-HS) is one of the most important processing methods. The wire tool can incline at an angle by a special taper device to get SCS parts in WEDM-HS, but this processing method can generate error easily and the low automation degree of its CNC system also reduces the SCS processing quality. Therefore, the research on the key technique of intelligent CNC system in WEDM-HS is proposed in this paper. The main content is given as follows.The processing technique includes its CAD/CAM technique and its Numerical Control (NC) technique. From these two aspects, the actual condition of SCS processing technique in WEDM-HS is resumed, the background and significance of this research are proposed at the beginning. Then, on the base of the main research works, the main content and the technique route of SCS intelligent CNC system are proposed by the application of Multi-axis motion control technique.As for the SCS mathematical module, on the base of machining means of swaying motions of parts, respectively in the Polar coordinates and Descartes coordinates, the general mathematical model and the universal database are established by the application of mathematical method and database technique. On the base of the analysis on normal ISO G code program, the G code interpretive system is established, and a high efficiency SCS composition method is proposed. All these works expand the SCS parts processing range.For the integration process of SCS CAD/CAM system, the graphic simulation platform is established which can model SCS, and simulate machining process, also can follow machining track in real time with several computer techniques.For the software and hardware architecture designing of CNC system, on the base of open architecture of Programmable Multi-axis Controller (PMAC) and opened architecture idea of five axes linkage machining in WEDM-HS, the NC system hardware architecture is developed.In order to realize real time characteristic of NC software, on the base of machining track stack and motion track dissection, the kernel module and user space program of multi-axis SCS NC software are developed. The PMAC motion program and PLC program of feed rate adjustment are established and the gap adjustment and motion track auto back functions are realized.For the mechanism designing of five axes linkage WEDM-HS machine, the structure characteristic and kinematics are analyzed. The whole mechanism design plan of SCS machining in WEDM-HS is proposed. The parameterized three dimensional model of the NC Rotary Table with Two Sways (RTTS) in Pro/E is established and the virtual prototype of RTTS is also established in Adams. On the base of analysis on dynamic property in Adams, the RTTS design plan is well validated. The RTTS prototype and the five axes linkage WEDM-HS which composed of the RTTS and normal WEDM-HS are established, and this entire works pay the foundation for the study on the high precision SCS machining.For improving machining precision of SCS, on the base of the analysis on bad influence of precision by the changed wire tool tension and the servo control technique, the constant tension control module of wire tool is proposed with the PMAC. The test results show that the bad influence of precision is well eliminated and the machining precision of SCS is improved.At last, the SCS machining tests are done and the machining test results show that the samples have a sound precision and the intelligent CNC system has a good rationality and stability.