Intaglio printing plate electroplating process - chrome plating: Strengthen conductivity management!
Release Time:
Sep 30,2017
Strengthen conductivity management
Currently, manyChrome platingQuality issues stem from poor current control, uneven current distribution, with high values at both ends of the drum and low in the middle, resulting in poor local adhesion, low and unstable hardness of the chrome layer. Therefore, it is essential to control the current difference well. The magnitude of the current difference at both ends of the drum reflects the overall conductivity during the electroplating process. Whether the conductive parts are clean and whether the contact is good are all reflected in the size of the current difference. The current difference has a significant impact on the overall quality of the chrome layer, such as left-right uniformity, local adhesion, wear resistance, and corrosion resistance, so it should be regarded as one of the main parameters for controlling chrome plating quality. Although some operators have a certain understanding of conductivity, they still lack understanding of the relationship between the current difference at both ends of the drum and conductivity, so it is necessary to strengthen management in this area.
(1) The conductive shaft should have good contact with the carbon brush and the drum, and surface contact should be maximized where possible. Otherwise, instability may occur during production when the rectifier converts AC to DC, or local passivation of the anode may happen.
(2) Keep the conductive parts clean and tidy, and regular cleaning should be performed.
(3) The installation must be firm, and the conductivity must be good.
(4) Power supply method: Use the impulse current power supply method. After the drum is placed in the tank, rotate for 1-2 minutes for preheating without current, then quickly supply a large current before reducing it to the normal current.
Note:It is crucial to pay attention to preheating before chrome plating. If preheating is insufficient, the cold drum may easily peel during hot plating, leading to chrome loss during printing.
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