Analysis of factors affecting accuracy of aluminum overprint

I often see some paper and plastic printing technology exchanges in the Journal of Printing World. I rarely see technical exchanges related to metal printing. I'll publish this article in your magazine today and I hope to work with my colleagues in metal printing. Technical exchanges to increase our level of metal printing.

Metal printing is divided into tinplate (tinplate) and aluminum plate printing. Although both tinplate and aluminum plate belong to the same metal, due to the great difference in structure between the two types of plates, the operator should reasonably adjust the characteristics of the aluminum plate when adjusting the equipment.

Our company has been engaged in aluminum plate printing for nearly 10 years. Here, I briefly introduce the problems that should be paid attention to to ensure the accuracy of overprinting.

1 Side pressure regulation

We know that the lateral gauge is a lateral positioning device that guarantees the substrate, so we must ensure that its components can meet normal production requirements.

1) Always inspect the wear of all parts, especially side bearings. Sometimes when we print, there will be horizontal misregistration, usually about 0.2mm. After careful inspection, it was finally found that the surface of the aluminum alloy plate was scratched by aluminum plates with a depth of about 0.2 to 0.3 mm due to the non-stop rotation of the side-face bearings, resulting in inaccurate horizontal overprint of the aluminum plate. After replacing the bearing, this problem is solved.

2) The lateral pressure of the equipment we use is controlled by the air pressure, and sometimes the air pressure is unstable. When we adjust, we generally control the air pressure to about 0.8MPa and the compression amount to about 2mm. Aluminum is a lighter metal. Pressure is too high and pressure is too high, which can directly affect the lateral overprinting.
2 Pressure adjustment of tray and spring pusher

The tray and the spring pusher are devices that ensure the longitudinal orientation of the substrate.

1) Try to ensure that the trays are on the same line. If there is too much difference between the two sides, overprinting is not allowed.

2) Check the tightness of the pusher chain frequently. If it is too tight, it may cause jitter. If it is too loose, feeding will be abnormal. Should try to ensure the same degree of tightness of the two chains.

3) Regularly inspect the wear of all parts of the chain and the spring pusher. If it is found to be worn out, replace it in time to ensure the smooth transmission of the chain. To extend the service life of the chain, lubrication is very important!

4) The spring type in the spring push handle should be reasonably adjusted according to the thickness of the aluminum plate. The compression amount of the spring pusher is generally 3~4mm.

3 Problems with the aluminum plate itself

1) The quality of the plates in metal printing directly affects the accuracy of overprinting, so preparation before printing is very important. Be sure to check the flatness of the aluminum plate, cutting size, etc. Flat and even plates are an important factor in ensuring overprint accuracy.

2) The unevenness of the sheet not only affects the precision of overprinting, but also the partial overprinting is inaccurate. Under the pressure of the printing platen and the impression roller, the aluminum plate may wrinkle, and the printing blanket may also be easily damaged.

3) Before printing, verify the stability of the rules, that is, use 10 to 20 aluminum plates for two consecutive overprints to confirm that the rules are correct and correct before mass production can be started.

4) Thermal expansion and contraction are also an important factor influencing overprinting. Our accumulated experience is as follows:

Preparation of aluminum plate and printing interval time should not be too long, it is best to arrange printing as soon as possible after the coating;
If the aluminum coating is stored for too long after some reason, it is best to bake it before printing. For products with very high overlay accuracy, the baking temperature is approximately 160°C.

(Author: Zhao Feng) "print world"

ceramic knife set

ceramic knife set,ceramic knives,ceramic knife

Ceramic Kitchen Knives Co., Ltd. , http://www.ns-ceramics.com