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 non-circular cross-section parts with large output, the Non-Circular Cutting Research Center of 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 large thrust is 160N, and the large acceleration can reach 13g. Since the linear motor mover and the table are fixed together, only closed loop control can be used.
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 accuracy depends on the resolution of the grating, and the mechanical error of the system can be eliminated by feedback, resulting in higher accuracy.
Open CNC system with linear motor
The PC and the open programmable power controller are used to form the numerical control system. This system uses the universal microcomputer and Windows as the platform, and the motion controller in the form of standard plug-in on the PC is used as the control core to realize the opening of the numerical control system. The overall design of an open CNC system based on linear motors.
The system consists of a scheme of inserting a motion control card into the expansion slot of the PC. The system consists of a PC, a motion control card, a servo drive, a linear motor, and a CNC workbench. The CNC table is driven by a linear motor. The servo control and machine logic control are all completed by the motion controller. The motion controller is programmable, and the NC program is interpreted in the form of a motion subroutine (G code, etc., to support user expansion). The motion control card model is PCI-8132.
In today's industrial control technology, the PCI bus gradually replaces the ISA bus and becomes the mainstream bus form. It has many advantages, such as Plug and Play (PlugandPlay) and interrupt sharing. The PCI bus has strict standards and specifications, which guarantees good compatibility and high reliability; high transmission data rate (132Mbps) or (264Mbps); PCI bus is independent of CPU, independent of clock frequency, suitable for each A platform that supports multiple processors and parallel operation; the PCI bus also has good scalability, and can be multi-stage extended through the PCI_PCI bridge. The PCI bus provides great convenience for users, and is an advanced and universal bus on the PC. The PCI-8132 is a 2-axis motion control card with a PCI interface. It can generate high-frequency pulse to drive stepper motor and servo motor, control motor movement of two axes, realize linear and circular interpolation. In CNC machining, position feedback is provided.
System software is developed on the WINDOWS platform. The software adopts modular programming and consists of user input and output interface and pre-processing module. The user input and output interface realizes the user's input and the output of the system. The main function of the user input is to let the user input the numerical control code, issue control commands, configure the parameters of the system, and generate the CNC machine tool part processing program (G code command). After the pre-processing module reads the G code command, it compiles and generates a program that can run the PCI-8132 motion control card, thereby driving the linear motor and completing linear or circular interpolation. The process of reading the G code is to first set the parameters and then read the G code.
If you want to buy a medical device motor, please pay attention to our new product -linear actuator for medical equipment.
