Electrical principle The electrical system applied to this type of printing machine, first of all, due to the use of non-shaft printing, there is no mechanical connection between the various printing axes, so it is necessary to ensure the high precision synchronous operation between a number of printing axes, so as to ensure the color between multiple colors Accurate. Secondly, due to the intermittent printing action, the two dragging shafts not only need to run synchronously, but also have to advance and retreat according to the position of the printing spindle. This requires the host controller to have high-speed and complex computing capabilities. It is difficult for ordinary PLCs to meet such requirements. In addition, it is necessary to ensure that the printing press can work at high speed and with high efficiency, and a highly responsive motor is also indispensable.
Figure 3 System Structure Figure 3 shows the system structure. The Yaskawa MP2300 motion controller as a host computer in this system is a high-speed, high-performance controller with multiple functions. It can control up to 48 axes and can use different control modules to achieve various functions according to specific requirements. . Positioning, constant speed feeding, interpolation, torque control, and phase control can be performed. It also has a full range of communication functions and is equipped with communication protocols such as RS232, RS485, RS422, Ethernet, DeviceNet, and Profibus. In addition, it also has a pulse and analog signal function. In addition, the MP2300 can also receive external encoder signals for counting. For two-pull spindles that require complex motion, Yaskawa's high-response servo motors are fully satisfactory. This motor has a high response frequency. Can reach 5000r/min.
In the communication of various electrical devices, the Yaskawa MP2300 motion controller uses MECHATROLINK-II high-speed field bus (communication rate is 10Mbps) to communicate with each axis servo motor. As a result, communication lines are greatly reduced, standardized connections are realized, and the possibility of interference is also reduced. The touch screen connected via RS232/RS485 is used as a man-machine interface to communicate with the host computer through RS232/Ethernet. The entire system's motion processing and logic operations are completed by the MP2300 motion controller. The programming of the program is accomplished by the MP2300 programming software MPE720 in the host computer. The programming language is a ladder language similar to the PLC. In addition, MP2300 also has a text language program editor - motion programs and function calls and other functions, multiple forms of programming language can greatly facilitate the implementation of complex functions.
Solution First of all, in order to keep the synchronous operation between the printing axes of various colors, in the Yaskawa MP2300 controller, the electronic axis function was used to realize the synchronous operation without a mechanical shaft. The electronic axis function is a speed control function with position compensation in the Yaskawa MP2000 series controllers. The pencil core test is well-known in Yaskawa (two servo motors operate with high-speed acceleration and deceleration, and the middle is connected with a 0.5-mm pencil lead. Keep the pencil lead free during operation. The electronic axis function is used. However, in the printing process, due to the large flexibility of the paper, the absolute synchronization of the printing axis often causes misalignment of the printed pattern. The traditional solution is to perform mechanical fine-tuning and registration. Now the position compensation of the MP2300 motion controller is used. Function, only need to input the compensation value on the upper computer, can carry on the register job among each printing axis, have simplified the operation greatly, have realized intellectualization.
Secondly, because the printing press adopts intermittent printing, the two dragging shafts perform the forward, backward and re-advance movements. In this process, the dragging shaft must not only run synchronously with the printing stencil during uniform printing, but also according to the printing spindles. Position for cam operation, in the MP2300 controller uses the electronic cam function, that is, according to the position of the printing spindle for any specified track operation.
As shown in Fig.4, setting one revolution of the printing axis to one cycle, that is, 360°, in the MP2300 program editing, it can be assumed that the drag axis accelerates from 0 r/min to the printing spindle in the case of artificially setting 0-x degrees. The running speed, xy degree (the specific length is set according to the length of the printing plate), the drag axis drags the paper and the printing axis synchronously prints, the yz degree decelerates and stops, and the z-360 degree drags the material axis to retreat a certain distance. Then proceed to the next printing cycle.