Application case of linear motor on CNC machine tools
The history of linear motors can be traced back to the unsuccessful prototype of linear motors produced by Wheatstone in 1840. For the more than 160 years, linear motors have experienced three periods of exploration, development, application and commercialization.
From 1971 to the present, linear motors have finally entered the period of independent application. The application of various linear motors has been rapidly promoted, and many practical devices and products have been made, such as linear motor driven steel pipe conveyors and coal conveyors. , various electric doors, power windows, etc. The maglev train driven by a linear motor has a speed of more than 500km/h, which is close to the speed of aviation flight.
The research and application of linear motors in China began in the early 1970s. At present, the main results are factory driving, electromagnetic hammer, punching machine and so on. Although China's linear motor research has also achieved some achievements, compared with foreign countries, there is still a big gap in its promotion and application. At present, many research units in China have noticed this.
Application examples of linear motors in CNC machine tools
Piston turning CNC system
The linear motion mechanism using linear motor has been successfully applied to CNC turning and grinding of profiled workpieces due to its fast response and high precision. For the non-circular cross-section parts with the largest output, the Non-Circular Cutting Research Center of the National University of Defense Technology has developed a high-frequency large-stroke CNC feed unit based on linear motors. When used in CNC piston machine tools, the table size is 600mm × 320mm, the stroke is 100mm, the maximum thrust is 160N, and the maximum acceleration is up to 13g. Since the linear motor mover and the table are fixed together, only closed-loop control can be used. Figure 2 shows a schematic diagram of the control system of the unit.
This is a double closed loop system, the inner ring is the speed loop and the outer ring is the position loop. A high-precision grating ruler is used as the position detecting element. The positioning accuracy depends on the resolution of the grating, and the mechanical error of the system can be eliminated by feedback to obtain higher precision [4].
