Heidelberg offset presses are world-renowned for their reliability and durability. The author has been engaged in equipment operation and management in the front line of printing companies since the early 1990s, and has formed an indissoluble bond with Heidelberg CD102. After a long-term production practice, the author found that the Heidelberg CD102 Feida can be improved by the following methods.
Improving Feida Rotary Distributor Valve
In actual production, many printing companies in Hubei have used the Heidelberg CD102 Feida rotary gas distributor valve to varying degrees of wear, and some of them have a cardan spring caused by the feeder rotary valve seizure. The pin breaks, and even the universal shaft twists.
1. The cause of the problem
After analysis, the author believes that the main reason why the Feida rotary distributor valve is easy to wear is the following.
(1) There are design flaws
The Heidelberg CD102 Feida rotary gas valve core is made of copper, and the valve housing is made of aluminum alloy. Among them, the inner wall of the valve hole in contact with the copper core has been hardened. The copper core and the valve hole have a clearance fit. The 16004 bearings at both ends of the copper core have an interference fit. The outer diameter of the copper core is only a few tens of microns smaller than the inner diameter of the valve hole (outer diameter of the bearing).
In the course of visiting the printing company, the author saw many Heidelberg CD102 Feida rotary distributor valves with varying degrees of sloshing overall. Because the copper core of the Feida rotary distributor valve of the Heidelberg CD102 is sleeved on a long shaft, this long shaft is integrated with the camshaft of the paper conveyor. Once the Feida rotary distributor valve is stuck, there is no design on the valve housing. Pull out the pin puller of the valve housing, and the three aluminum end cap screw holes will be broken when pulled with the pin puller, so you can only use a screwdriver and pry bar to pry out the valve housing a little. When the valve housing is forcibly pulled out, the long axis will inevitably be bent and deformed. After reinstalling the valve housing, under the influence of the bent long axis, the entire Feida rotary distributor valve will sway, which aggravates its copper core. abrasion. Due to the bending of the long axis, it is very difficult to calibrate. Even if a new set of Feida rotary distributor valve is replaced, the swaying problem cannot be solved. It will not be long before the Feida rotary distributor valve is still worn and scrapped.
(2) Improper maintenance
In actual production, due to the needs of the printing market competition, Heidelberg CD102 will be used to print a large number of uncoated papers (writing paper, offset paper and even newsprint). This kind of paper has serious powder and hair loss. The powder sprayed particles are sucked by Feida rotary distributor valve. The maintenance manual requires the printing company to extract the valve housing for cleaning at least once a month to remove the paper dust accumulated on the surface, but the printing company often does not clean according to the maintenance manual due to cost and other reasons, resulting in wear and tear of the Feida rotary distributor valve, or even Stuck phenomenon.
In addition, the climate in the southern region is humid and the air humidity is high. From the perspective of cost, some small and medium-sized printing companies cannot guarantee the constant temperature and constant humidity environment required for printing through air conditioning. The Feida rotary distributor and the bearings at both ends are Metal material, easy to rust in wet environment. When Feida is running, the rust powder will scratch the copper core and the inner wall of the valve hole, causing string and air leakage, which will affect the feed function of Feida.
2. Improvement methods
Based on the above analysis, the author believes that the following improvements can be made.
(1) Disconnect the long axis of the copper core from the feeder camshaft and connect it to the camshaft through the coupling
The original long axis is divided into two. After the long axis becomes shorter, the risk of bending deformation is greatly reduced. Even if the axis is deformed, the Feida rotary split valve is also self-contained, and there will be no shaking phenomenon. Once the air valve is stuck, just remove the whole valve and knock out the copper core. Disassembly becomes very easy.
(2) Improve and optimize the material of the valve housing
It is recommended that the valve housing be made of a metal material with better hardness, and the round hole of the valve housing be designed as an independent cylindrical hole, which is fitted on the Feida rotary distributor body. Therefore, once the Feida rotary distributor valve is worn, it will only damage the copper core. Even if the valve hole is damaged, it can be replaced separately without affecting the entire housing, thereby greatly reducing costs.
(3) Properly increase the gap between the valve hole and the copper core
After experiments, after the Feida rotary distributor valve was severely worn, the Heidelberg CD102 can still be printed at a speed of 12,000 sheets / hour. It can be seen that the gap between the valve hole and the copper core is increased by an appropriate amount (about 0.05mm increase), which will not affect the Feida output. Paper function, and the possibility of Feida rotary distributor valve stuck is greatly reduced.
(4) Printing enterprises should conduct standardized management
The printing company should ensure constant temperature and humidity in the workshop, and perform regular maintenance on the Feida rotary distributor valve to avoid it from being stuck.
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