The automatic paper feeding section can be divided into three types based on the mode of paper operation: intermittent, continuous, and variable speed paper feeding. At present, continuous paper feeding is widely used both domestically and internationally, where there is always a portion of the front and back sheets of paper overlapping together. This method of paper feeding is smooth and fast. At the same die-cutting speed, assuming that the paper has the same stability time at the front gauge, the intermittent paper feeding speed is much faster than the continuous paper feeding speed. As the paper feeding speed increases, there will be a significant impact when the paper moves towards the front gauge, which can easily cause the paper to bounce or curl, resulting in inaccurate positioning and reduced accuracy. When the paper feeding speed is equal, the positioning time of intermittent paper feeding is much shorter than that of continuous paper feeding, which can cause unstable positioning of the paper at the front and side gauges, and also lead to a decrease in accuracy. If you want the intermittent paper feeding to have sufficient paper stability, you need to reduce the speed of the machine, thereby reducing the die-cutting capacity. Therefore, intermittent paper feeding is generally only used for small size and low-speed machines, while continuous paper feeding is mostly used for large size and high-speed machines.
In recent years, variable speed paper feeding has been adopted on high-speed die-cutting machines. The working principle of variable speed paper feeding is basically the same as that of continuous paper feeding, with the addition of a paper feeding variable speed mechanism. If the average speed of paper feeding is equal, the positioning time for variable speed paper feeding and continuous paper feeding is the same, but there will be periodic changes in the speed of each paper feeding step for variable speed paper feeding. When the paper reaches the front gauge, the feeding speed reaches the lowest, the paper has little impact, and the positioning is accurate, which is conducive to improving the die cutting speed and accuracy.
The influence of gauge body components on speed and accuracy
The accuracy issue of the product mainly lies in the die-cutting part of the automatic die-cutting machine, where the gauge components play a crucial role. Before the paper enters the paper gripper, the gauge body accurately positions it to ensure that the cutting marks and indentation lines are at the same position on each sheet of paper during the die-cutting process, meeting the requirements of high die-cutting accuracy. The positioning of the paper on the regular components requires accurate positioning in both the front and rear directions, as well as the left and right directions, which are guaranteed by the front and side gauges respectively.
The positioned paper must also have a high-precision paper transfer mechanism, which accurately transfers the paper into the die-cutting indentation plate through the paper teeth arrangement. In order to ensure the accuracy of die cutting, it is necessary to ensure accurate transmission and ensure that each row of teeth stays in the correct position. The accuracy and stability of the tooth array stop play a crucial role in the accuracy of die cutting, and its movement, rest time, and stability are all determined by the intermittent mechanism of the die cutting machine.
The Influence of Intermittent Mechanisms on Speed and Accuracy
The intermittent mechanism of the flat press die-cutting machine generally adopts parallel indexing cam mechanism, which is a conjugate cam mechanism. Compared with intermittent motion mechanisms such as groove wheels and incomplete gears, this mechanism has good motion characteristics, stable start and stop, low vibration noise, and compact structure. It is widely adopted due to its advantages such as convenient processing. When the machine speed is high, the cam profile is affected by the speed, acceleration, inertia, and direction of the follower, causing the mechanism to vibrate and making the paper feeding teeth unstable. Therefore, on the basis of adopting the principle of Kinematics for design, it is also necessary to adopt mechanical dynamics for dynamic design of the cam profile to ensure the smooth movement of the intermittent mechanism itself.