Evaluation of the cardboard sheet behavior in pulling the pressure cylinder

Abstract

The article presents the advantages of flat­cylinder presses. The work of such pres­ ses is based on the principle of minimizing of contacting surfaces, which make them uni versal in terms of changing of the thickness and format of the cardboard sheets, prompt readjustment to another type of packaging. For the stable flat­cylinder presses func -tioning, technical problems need to be solved: to ensure even movement of the pressure means during the die­cutting process, to minimize the negative impact of inertial loads due to the deceleration and acceleration of the pressure means in the extreme positions, to provide shortening, fixing and the output of the die­cut sheet. The article shows the analysis of forces effects on a freely placed cardboard sheet on the fixed die­cutting forme during the movement of pressure cylinder. With the aim to de termine the need of additional gripping or clamping mechanisms during the cardboard packaging manufacture on flat­cylindrical die­cutting presses with fixed form, analytical researches of forces have been made in zone of contact between cardboard sheet and cylinder. The analytical dependencies of component forces that arise during the pro cess of die­cutting of the cardboard packaging on flat­cylinder presses with a movable pressure cylinder are presented. It is established that the value of the total clamping force depends on the specific operating conditions of the equipment. The article shows an analytical dependency of the effort that provide sufficient fixation of cardboard sheet on a flat die­cutting forme in flat­cylinder presses. It is found that the value of the total vertical force is most significantly influenced by the angle of onset of contact of the pressure cylinder with a sheet of cardboard. The increase of cardboard sheet thickness and decrease of the pressure cylinder radius cause the increase of needed vertical force.