Research On The Multi-Axis Transformation Of The Three-Axis CNC Machine Tool Based On The Rotary Worktable

CNC machine tool is the mainstream equipment of the contemporary machinery manufacturing. The technology level of CNC machine tool determines the development level of the entire national economy. Today people in countries' machinery manufacturings widely use new CNC machine tools in order to increase manufacturing capacity and improve the adaptable ability and competition ability against the dynamic changes in the international market. China's manufacturing has also brought forward a request on updating timeworn CNC machine tools, but the development level of our country's overall CNC machine tools is not high. In the practical application, the middle-grade and low-grade CNC machine tools account for a large proportion, which is quite difficult to be changed. However, with the continuous development of numerical control technology and machinery manufacturing technology, it must be a broad prospect that the modern alteration is against the backward CNC machine tools.At present, the compound multi-axis processing is becoming the mainstream in the CNC machine tool development. Although the manufacturing demands for a large numble of the multi-axis CNC machine tools, but the general multi-axis CNC machine tools are more expensive and more senior CNC machine tools or CNC processing centers. This paper is to resolve contradiction between supply and demand for designing a rotary worktable. The ordinary 3-axis CNC machine tool with rotary worktable is able to realize multi-axis linkage. After the transformation of the 3-axis CNC machine tools, the new avoids repeated clamping workpieces. With the rotation of rotary worktable, the single-clamped workpiece may be processed in multi-process, multi-surface compound processing.In this paper, the type of CNC machine tool for the transformation is ZJK7523A-4 3-axis vertical CNC machine tool with frequency spindle. On the base of maintaining the original mechanical structure and numerial control system, the rotary worktable can be directly installed on original CNC machine tool worktable. In the processing, when the processing head of ZJK7523A-4 3-axis vertical CNC machine tool moves in the X, Y, Z-direction, the workpiece can follow the rotary worktable around X, Y and Z-axis. The perfect cooperation between processing head and rotary worktable results in the ultimate realization of a multi-dimensional compound processing.This study includes the design of mechanical structure, the design of movement system, the design of numerial control system and the design of software and programme. Firstly, the space movement principle and kinetic model of rotary worktable are established. In accordance with the processing of the actual machine tool, the main performance and technical index are confirmed. Eventually the mechanical structure with inside frame, middle frame and outside frame is established. Secondly, Mitsubishi AC servo motors are connected directly to the various rotary frameworks as the drives of the movement system. The capacitance of AC servo motor is in the light of the actual movement inertia of of the rotary framework.In the numerial control system, Mitsubishi MR-J2S series servo drives and AC servo motors constitute the whole servo system. Photoelectric encoders as position feedback devices make the speed control and location control become a closed-loop control. The MR-J2S P1D control parameters can be set up by the software which is provided by Mitsubishi. Mitsubishi FX2N-32MR PLC controller is not only used to accept, compile and implement the orders of the upper men-machine operation system, but also to gather, transformate and transmite the real-time data of the down servo system. Mitsubishi FX2N-10PG pulse output module is used as a position controller in a high-speed pulse control servo system. The function and parameters of FX2N-32MR can be designed with the PLC ladder programme.Man-machine interface (HMI) is designed with Visual Basic 6.0 software, which realizes the rotary worktable's state show and operation control. The rotary worktable's state includes real-time data display and real-time location drawing. The operation control mode includes automatic operation, manual operation, and point operation. Each operation mode has the special operation method. HMI and PLC use RS232 serial communication. The idiographic communication protocol is designed with communication controller MSComm of VB 6.0 and the special communication programme.