Experimental Research on Linear Feed Unit of High Speed CNC Machine Tools . The rapid development of modern aviation, aerospace, and automotive manufacturing places higher demands on manufacturing precision and processing efficiency. In order to realize high-precision, high-efficiency processing, in recent years, developed industrial countries such as the United States, Japan, and Germany have made great progress in the research and development of high-speed numerical control machine tools, and have made great progress in the research and development of high-speed numerical control machine tools. The rapid development of high-speed
CNC Machining technology has been achieved. Among them, the research of high-speed linear feed units is one of the key technologies for high-speed machining.
The traditional CNC machine tool adopts the feed method of rotating servo motor + ball screw, and has a long transmission chain, which makes it difficult to increase the acceleration and deceleration of the feed system. For decades, its maximum acceleration and deceleration have stayed at 0.1-0.2G (G=9.8m/s2). Because the feed distance of the machine tool is short and the acceleration has not reached the maximum feed rate, it must be decelerated, which limits the increase of the maximum feed speed of the machine tool and makes it difficult for high-speed machine tool development.
The development of high-power linear motors and the development of advanced frequency conversion control technologies provide favorable conditions for the development and development of high-speed feed systems. The workbench directly driven by the linear motor not only eliminates the intermediate transmission link and enhances the transmission efficiency, but also greatly improves the speed and acceleration of the feed system, and can be well developed for high speed machining.
GD-4 high-speed linear feed unit, GD-3 high-speed linear feed unit directly driven by a linear motor, the system structure shown in Figure 1. The system adopts a dynamic primary, fixed secondary, short primary, and long secondary structure, in which the primary is connected to the mounting surface of the workbench through the cooling plate, and the secondary is laid in series on the bed through the cooling plate. When the primary enters a three-phase alternating current, a traveling wave magnetic field is generated, and the secondary is cut so that the secondary generates a potential, thereby forming an induced current in the secondary closed loop. The secondary inductive current interacts with the primary alternating magnetic field to generate an electromagnetic thrust that causes relative motion between the primary and secondary. The speed of the motion is proportional to the speed of the travelling wave magnetic field. Using variable frequency speed control technology, by adjusting the frequency of the power supply to change the speed of the motor, the high-speed linear feed motion of the table can be achieved.
In the GD-3 linear feed unit, the maximum feed speed of the linear motor is 100m/min, the maximum starting thrust is 4550N, the rated thrust is 2000N, and the rated power is 8kW. The system adopts a grating measurement feedback device and the feed unit Closed-loop control, raster resolution of 3μm, control system structure.
