Repair of JJ20 Offset Roller

A JJ201 offset press of our factory was purchased in 1987. After many years of use, the cylinder surface of the upper and lower blanket cylinders of the second unit was severely corroded, the amount of corrosion was uneven, and printing and word dropout often occurred during printing. In order to solve this problem, the operator uses the trapezoidal pad method when padding paper, which has a certain effect. However, after running for a period of time, it was found that such a paper pad is not the fundamental method to solve the problem, because this pad paper is time-consuming and laborious, and after several test pads, it can be aligned, and sometimes the potential paper can be displaced. Finally, the factory leaders decided to solve this problem.
After we removed the two rubber cylinders and measured them, we found that the amount of corrosion was different at several points on the straight line with the same parallel axis on the cylinder; the same circumferential line, the amount of corrosion at several points was also different. The corrosion of the surface of the cylinder near the rubber groove is up to 0.41mm, and the corrosion surface is in fine spots.
Corrosion amount of such a large roller, if sent to the outside repair, each repair contract signed about one million; if you replace a new piece, each root should be more than 20,000 yuan. How can we not only reduce costs, but also completely solve the problem? Inspired by the hard lining of the plate printing cylinder of the Hudderberg 102V four-color machine, we decided to use the lining method to recover the size of the cylinder after finishing the blanket cylinder. The basic approach is this:
Remove the two rubber rollers with an accuracy of 0.45 mm (without grinding shoulders), clean the surface of the roller with gasoline, and clean the surface with an alcohol swab. After drying, clean the surface with a clean cloth. According to the effective format of the blanket cylinder, the plate of the 102V four-color machine is lining (thickness 0.35mm, one side with glue, protective paper on the rubber), cutting and growing 510mm, width 940mm, and roll the liner into a tube The inner diameter is less than 15 gamma m. After the banding is allowed to stand for 20 minutes, the covered protective paper is peeled off and the inner liner is placed on the rubber roller body. During the entire operation, the blanket cylinder can be placed on the machine for processing. When sticking, slowly turn the roller while firmly pressing the pad onto the roller with your hand, and timely squeezing the lining (especially the edge part) of the adhesive on the roller. After bonding, the four corners of the pack were cut into circular arcs with a radius of 10 mm with a utility knife to reduce stress concentration. Finally, wrap the drums with several pieces of kraft paper, tie them with a rope at a distance of 5cm, and place the drums tightly. After 2 hours of parking, put them on the printing press.
When used, additional 0.1 mm thick backing paper is required on the blanket cylinder for proper printing.
After one year of use, the printing quality of the second unit fully meets the requirements. No signs of detachment have been found when checking the bonding condition of the lining. Even if it is detached, the lining can be replaced without disassembling the lining.
We figured it out: The total cost of this repair method is no more than 2,000 yuan. We feel that this repair method is simple, saves money, saves time, and has good results.