Corrugated printing machine control system
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
The shaftless rotary corrugated printing control system adopts PLC as the main control system. The printing plate roller, ink roller, paper feed roller and electronic cam are all servo drive. The stepping motor adjusts the gap, the man-machine interface is monitored centrally, and the field bus collects and transmits signals. Combined with high-precision reducer, coupling, encoder, slide screw, timing belt and other mechanisms, the speed synchronization and phase synchronization of each roller under high-speed operation are realized, and the vacuum adsorption electronic cam feeding mechanism ensures fast and accurate paper feeding. The phase adjustment function of the system makes adjustments easy. All of this greatly increases production speed, overprinting accuracy and ease of operation.
System Components
The system consists of a paper feeding section and a four-color printing section, and the paper feeding section mainly includes an electronic cam vacuum suction paper feeding mechanism and a paper feeding roller. The electronic cam vacuum adsorption paper feeding mechanism uses the negative pressure generated by the fan to make the paperboard adhere closely to the paper feeding platform. The two electronic cam servo motors drive the paper feeding platform to synchronously reciprocate between the paper feeding upper and lower positions, cooperate with the paper feeding roller and paper feeding. The roller finishes the cardboard transfer in sequence. On the basis of the roller friction coefficient and the stability of the paperboard pressure, the paper feeding timing is related to the position and production speed of the one-color printing plate. At a certain speed, when one color printing plate is turned to a certain position, the paper feeding starts, and the paper is transferred to another position. The paper feed is stopped to ensure that the plate can be accurately printed on the cardboard at each position. For different specifications of cardboard, the timing of sending/stopping paper is also changed accordingly. The operator only needs to adjust the material number on the man-machine interface, and the system will automatically adjust immediately to ensure the printing position is accurate. The action, speed and rotation angle of the two electronic cam motors must be identical to ensure continuous and stable operation of the motor and mechanism, and the cardboard is sent straight. Here, we use two-axis simultaneous linear compensation to achieve real-time synchronization of two axes. In addition, the cam motor also needs to meet the needs of long-term frequent reciprocating forward and reverse operation. It is required to select a high-response servo system and adjust the servo parameters in combination with the load to fully utilize the high-speed and high-response characteristics of the servo system to minimize the transmission links and each. Delay in the link, at the same time, we must fully consider the system heating and recovery protection issues, so that the motor work in a light load state (equipment and system structure diagram is as follows).
After the cardboard is sent out, it enters the four-color printing department. Each color control is completed by the printing plate roller, the ink roller, the paper roller, the paper-feeding roller and the cylinder. Each roller is directly or indirectly driven by a servo, and there is a stepping motor. Adjust the roller gap and position with the encoder.
The diameter of the printing plate roller is usually large, the running speed is fast, and the printing overprinting precision is required to be high. Therefore, the slight speed difference between the printing plate rollers causes the overprinting to be inferior in a short time. It is assumed that the speed difference between any two printing plate rollers at any time is ΔV, and the system speed loop adjusts the speed difference within Δt time. Because the transmission mechanism has a small delay, set to 0, the speed difference will be Δt time. The deviation of ΔV is set to ε, and the formula can be summarized as follows:
ε=∫0△t△Vdt
It can be seen that the smaller the speed difference ΔV between the loads, the faster the system response (ie, the shorter the Δt), the smaller the overprint deviation ε is. This requires improving the mechanical precision on the one hand, such as better installation concentricity, uniform load inertia, etc. In addition, the system should be fully matched with the load when matching the system, and provide sufficient responsiveness while providing sufficient load torque. At the same time, debugging is also very important, combined with the load to make the system perform optimally. In this regard, the servo system's automatic detection function can be used to detect the load condition first, and then match the parameters according to actual needs (such as increasing the response or reducing the overshoot amount, etc.), and further fine-tuning until the conditions are met. At the same time, because each load and its transmission mechanism are not the same, the parameters of each servo will be slightly different, and the difference of the mechanical transmission coefficient of the load should be compensated by electric.
The system uses the PLC's motion control function to control the servo system in real time. It uses a separate high-speed processor, and the operation is independent of the CPU. The servo system meets the requirements of high precision and fast response. The load shaft end encoder signal is also collected to detect and correct the load operating condition to eliminate the influence of the transmission error and to facilitate the analysis of the search problem.
The line speed between the rollers should be the same to avoid the slippage of the cardboard, and the ink on the ink roller will be uniform and colorless. In addition, the action of the ink roller cylinder is also very important. When the paper feed starts, the cylinder rollers move the ink roller to drop in order to inject the ink into the printing plate; when the paper feeding is stopped, the ink roller is lifted in order to prevent the printing plate from being too dark. The timing of the drop and lift is determined by the position of the plate to ensure the ink position and the amount of ink on the plate, thus ensuring the print quality.
Due to the large number of specifications of cardboard, the process and control of different specifications of cardboard printing should be adjusted accordingly. At the same time, equipment cleaning, maintenance, hanging and other work are often carried out, which will inevitably cause human error, and often need to be applied to the printing plate roller. Phase adjustment, these are implemented in the program, the operator only needs to adjust the item number and correction value on the man-machine interface, no need to make any changes to the device, easy to operate, greatly improving work efficiency and flexibility.
In addition, in the course of practice, we have summarized a set of simulation registration test methods and debugging work. The servo feedback and the encoder signal are detected by the PLC, and statistical analysis is performed thereon, and the phase difference (pulse value) of each printing plate roller at any time can be calculated, and then converted into a length (mm), and the mechanical registration accuracy can be measured. No need for ink and cardboard, saving a lot of material and reducing the time required for commissioning.
Performance and characteristics
1. Thanks to the servo drive, its high speed, high precision and high response make the production speed greatly improved. The traditional equipment usually has a maximum production speed of 80 sheets/min. This system can double the production speed of the machine to 160 sheets/min. .
2. The closed-loop design and fast response capability of the system enable the device to maintain extremely high control accuracy at high speeds, with overprint deviations ≤ ± 0.25-0.4 mm (depending on mechanical conditions).
3. The electronic cam vacuum adsorption paper feeding mechanism changes the traditional push-push feeding mode, which does not cause the cardboard to bend or even feed, and can avoid the inaccurate positioning of the cardboard, thereby ensuring the overprinting precision, and on the basis of this, the paper feeding is greatly improved. speed. In addition, the application of electronic cams makes it easy to transform production without the need to adjust any equipment.
4. The system adaptive synchronization control only needs to change the speed of the paper feed roller or any printing plate roller, and the other rollers automatically follow up, keeping the line speed and phase synchronized at the same time, and the feeding frequency and the feeding/stopping timing also change. Guarantee overprint accuracy and position.
5. The electronic cam and recipe function make the transformation of production very simple, no need to adjust the mechanical mechanism, as long as the production part number is changed on the man-machine interface, it can be easily realized.
6. The printing plate roller must find its initial phase before each operation. The traditional equipment is usually positioned with a high-precision encoder. This system can save this input and simplify the work through the program. The operator only needs to follow the instructions. The prompt on the man-machine interface can be operated. In addition, due to the initial phase shift caused by hanging plate or installation and maintenance, it can also be adjusted freely on the man-machine interface without stopping or powering down.
7. The application of the fieldbus system saves the equipment a lot of cumbersome installation and wiring work and space, ensures the stability, speed and accuracy of signal transmission, and enhances the maintainability of the system.
Conclusion
Because the system has the above characteristics, especially its advantages of high efficiency, high precision, and high flexibility, it has attracted the attention of many packaging and printing companies after being applied to the equipment. However, there are only a few such technologies in use in China, and most of them are imported or joint-venture cooperation technologies. There is no independent intellectual property rights, and their high price has also discouraged many enterprises, especially small and medium-sized enterprises. Therefore, we hope to promote the promotion of this technology in China and create better benefits for more enterprises.