Complex analysis of the pressure plate drive mechanisms functioning in die-cutting presses

In the process of manufacturing cardboard packaging, the main technological ope­ration is stamping, which forms the configuration of the cardboard sweep. The most common is the equipment in which flat punching is implemented, in such presses the main mechanism is the drive mechanism of the movable plate, which moves parallel to the statically fixed stationary plate. This work has done research on publications and inventions for improving the die-cutting press mechanism. Here the works of world scientists are researched, who have proposed mechanisms that eliminate certain short- comings of existing die-cutting press mechanisms but also have their own short­co­mings. The authors of the article have made a kinematic analysis of already existing mecha­nisms (BOBST, Heidelberg) and proposed a comparative characteristic.

According to the derived equations, the relative parameters of the pressure plate (dis­placement, speed, and acceleration) are calculated. The curves’ of the pressure plates’ relative movement nature for the eccentric-sliding and eccentric mechanisms is similar. It shows that the pressure plate moves faster than the stationary one and stays longer in the technological operation of punching sweeps in these mechanisms. In the wedging mechanism, the movements of the right and left sides of the pressure plate are not synchronized, which causes its oscillating motion. In the two-slider mechanism, as in the wedge mechanism, the pressure plate moves more smoothly to the extreme position.

Based on the results of the pressure plate relative speed analysis, its most prominent peaks are characteristic of the two-slider and wedging mechanisms. Slow plate accele­ration is detected in the two-slider mechanism and faster in the eccentric-slider mecha­nism. In addition, the graphs of changes in the relative speed of the pressure plate in the eccentric-slider and eccentric mechanisms are similar.

The wedging mechanism provides the maximum value of the relative acceleration of the pressure plate at the moment of contact with the stamping die. In this case, the pressure plate mass inertia force is maximally used in the process of punching the sweeps to overcome the technological resistance. In eccentric and eccentric-slider mechanisms, the start of the cycle is accompanied by peak values of the relative acceleration of the pressure plate, which requires energy costs to overcome the inertial load at this stage. The two-slider mechanism provides an almost constant relative acceleration of the pressure plate during the rotation angle of the main shaft in the range of 165° - 195° during the phase of punching the sweeps.

Because of the work performed, it can be stated that there is an urgent task of im­proving the drive mechanism of the flat die-cutting machine in terms of energy efficiency, productivity, quality of punching and ease of manufacture.

Keywords: pressure plate, punching press, cardboard sweeper, cardboard packaging, technological effort, wedging mechanism.

doi: 10.32403/0554-4866-2022-2-84-88-98