1, plastic packaging printing when using gravure printing, the shortcomings of the traditional platemaking method?
(1) The plate-making process is complex, and most of it is manual operation, so it is difficult to realize data-based control;
(2) Using carbon paper plate, printing plate accuracy is not high, can not be printed high-grade color printing;
(3) No jointless platemaking can be realized;
(4) It is not technically stable and requires high operation skills;
(5) Relatively high cost of plate making.
As a result, this method can only be applied to the printing of low-quality prints, and with the increasing demand for print quality, this method of platemaking has been gradually phased out.
2. What is the purpose of chrome plating?
After the establishment of a printing plate graphics and text, but also a layer of chromium plating, chromium plating is to improve the surface hardness, protect the printing plate roller, thereby improving the printing plate resistance. Because the chromium plating layer has a strong hardness and wear resistance and chemical stability, can make the plate roller surface has a good mechanical strength, and can make the plate for a long time to keep the gloss.
The electrolytes used for chrome plating are mainly chromic anhydride and sulfuric acid. The key to electroplating process is to control the current and electrolyte temperature well. The temperature is generally controlled at 50 ~ 55℃. It is better to change the temperature at ±1℃ in the electroplating process, and ensure the electrolyte temperature is uniform. If the condition allows, the current can be increased. The higher the current, the higher the hardness.
3, in the plate chromium plating process, there is a poor coverage, how to solve?
In the chrome-plating process of a plate, poor coverage, if the sulfuric acid content is too high, an appropriate amount of BaCO3 can be used to reduce the sulfuric acid content. If it is caused by the high content of metal impurities such as chromium trivalent or iron, the content of chromium trivalent can be reduced or the impurities can be removed by ion exchange.
4, in the printing plate chrome plating process, there is no chromium plating on the local surface should be how to deal with?
In the printing plate chrome plating process, there is no chromium plating on the local surface, if the temperature is too high, it is necessary to reduce the temperature, if the plating surface oxidation film or oil, it is necessary to strengthen the chromium plating pretreatment. If the current density is too low, increase the current density. If it is caused by bad contact or other reasons, the contact point should be inspected and cleaned.
5, in the plate chrome plating process, chrome plating layer hardness is low, gray color, how to deal with?
Chromium plating process in the plate often appear chrome plating layer hardness is low, gray phenomenon, if it is due to temperature and current density mismatch, should be adjusted to the normal range. If the sulfuric acid content is too small, it needs to be analyzed to adjust the sulfuric acid content.
6, in the chrome-plating process in a plate plating coating edge black or gray color, how to deal with?
In the process of chrome-plating plate often appear black or gray coating edge phenomenon, if it is due to the current density is too large, the need to reduce the current density. If the temperature of the electrolyte is too low, you need to raise the temperature of the electrolyte. If the current is too high when the roller is slotted, it is necessary to control the current density when the roller is slotted.
7, in the plate chrome plating process often appear the deposit deposit rate is slow, how to deal with?
In the chromium-plated plate process, the deposit deposit rate is slow, may be due to poor conductive performance, the way to eliminate is to check the anode and cathode conductive performance.
8. Which aspects should be tested for the copper plating quality of roller?
(1) Visually inspect whether the surface is smooth after copper plating. Require coating surface is very bright and clean, no burr and bubbling, peeling and other phenomena.
(2) check with a hardness tester to see if the hardness of the copper layer is within the specified range. If the hardness is too high will dilute the concentration of additives in the electroplating solution, otherwise it will be reduced.
Measure the thickness of the coating. Here refers to the thickness of the plate copper layer, it needs a certain thickness, otherwise it will bring difficulties after processing. Of course, the thickness depends on the way of finishing and the allowance of finishing.
9, roller plate quality should be tested in which aspects?
Roller plate making quality shall be tested in the following aspects:
(1) Check whether the fitting signal mark and gauge line on the roller are correct.
(2) After the roller plate making, it is best to use the dot detector to check -- under the dot depth, middle adjustment, dark and high profile.
(3) Check whether the roller size is correct.
(4) Check whether the pattern arrangement is correct.
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