In the printing process, the center distance and clearance of the drum are properly adjusted, and the lining value of each drum is calculated, which is beneficial to improving product quality and production efficiency. In the actual work, I summed up a method for calculating the center distance and clearance of the offset roller of the offset printing machine. It is not necessary to memorize various formulae. It is quick and simple for reference by peers. Domestic offset press J2108, J2203, J2205 and other models of the same drum parameters, now using J2108 offset press as an example as follows:
First, the cylinder center distance, clearance calculation method J2108 Offset drum design parameters shown in Figure 1 (slightly).
As can be seen from FIG. 1 , the radius of the printing plate roll is 149.9 mm, the radius of the plate cylinder is 149.5 mm, the radius of the rubber roller is 150 mm, the radius of the blanket cylinder is 146.75 mm, the radius of the embossing roll is 149.75 mm, the impression cylinder The radius of the body is 150mm, and the distance between the axes of two adjacent rollers is called the center distance. In practice, there are two ways to measure the center-to-center distance: one is to measure the clearance of the sleeper and the other is to measure the clearance of the shell of the drum. Both of these methods can correctly calculate the center distance of each roller. Formulate the equation according to the parameters in the figure:
Set the gap between the printing cylinder body and the rubber cylinder body after pressurization is X, and the gap between the impression cylinder body and the rubber cylinder body after pressing is Y, then:
149.9+150+0.20=149.5+146.75+X
150+149.75+0.20=146.75+150+Y
Solve the equation X=3.85mm, Y=3.20mm
That is, the gap between the plate cylinder body and the blanket cylinder body after the pressure is 3.85mm, and the gap between the impression cylinder body and the blanket cylinder body after the pressure is 3.20mm, and the center distance after the plate cylinder and the blanket cylinder are pressed For 300.10mm, the center distance between the impression cylinder and blanket cylinder is 299.95mm.
Second, the calculation method of roller lining value We all know that the printed paper thickness is different, then the plate cylinder and the rubber roller lining value is also different, take 0.10mm thick paper as an example, find the package lining value.
1. Calculate the gap between the blanket cylinder and the impression cylinder has been calculated as 3.20mm before the blanket cylinder liner value, then the blanket cylinder liner (rubber, cloth, liner) pad at least to 3.30mm.
2. For the plate cylinder liner value, the gap between the plate cylinder and the blanket cylinder is now known to be 3.85mm, and the blanket cylinder liner value has been cushioned to 3.30mm, and the plate cylinder liner value is 3.85-3.30+. 0.10=0.65mm...