In the circuit board production, there are four kinds of special plating method, which is a series of electroplating equipment, through hole plating, roll wheel linkage plating, brush plating, this paper gives a detailed introduction of these four special methods.
1, refers to the row electroplating equipment
In electroplating often needs to be plated on the wear resistance of rare metal plate edge connector, plate edge contact or prominent gold finger to provide low contact resistance and high technology, this is called refers to row type electroplating or electroplating part.Also used in electroplating gold plating on inner coating for nickel plate edge connector protruding contact, finger or edge projections using manual or automatic electroplating technology, the contact plug or finger on the gilded lead plating, plating has been replaced by the button.
2, through hole plating
There are many ways to establish a layer of the electroplating layer on the hole wall of the hole, which is called the hole wall activation in the industrial application. The production process of the printed circuit requires a plurality of intermediate storage tanks, each of which has its own control and maintenance requirements.
Through hole plating is necessary to process the subsequent drilling process, when the substrate over copper foil and the drill, the heat generated a synthetic resin insulating substrate melting most of the matrix, the molten resin and other drilling debris piled up in the hole, the hole wall is coated on the copper foil exposed on the new.
In fact, the subsequent electroplating surface is harmful, but also the residual molten resin layer on the substrate thermal shaft hole on the wall, it is for the majority of activators have shown poor adhesion, which requires the development of a similar to stain and etch back Chemical Technology: ink! The ink used to form high adhesion, high conductive film on the inner wall of each through hole, so that you do not have to use a chemical process, only one application steps, followed by heat curing, can form a continuous film on the hole wall inside all, it does not require further treatment can direct plating. This ink is a resin based material, it has a very strong adhesion, can be easily bonded to most of the hot polished hole wall, thus eliminating the erosion of this step.
3, roll wheel linkage selection plating
The pins and pins of electronic components, such as connectors, integrated circuits, transistors, and flexible printed circuits, are selected to obtain good contact resistance and corrosion resistance.
This method can be used for manual electroplating electroplating production line, can also be used in automatic electroplating equipment, single choice plating very expensive for each pin, it must be used in electroplating production batch welding, usually at both ends of the metal foil rolling into the desired thickness of cutting, cleaning method by chemical or mechanical then, the choice for continuous plating like nickel, gold and silver, rhodium, button Huoxi nickel alloy, copper nickel alloy, nickel and lead alloy.
4, brush plating
The last method is called "brush plating": it is a kind of electrodeposition technology, not all parts of the plating process are immersed in the electrolyte. In this plating process, only a limited number of areas are electroplated, but no effect on the rest.
Usually, the rare metal is plated on the printed circuit board, such as the area around the board connector. The use of brush plating in the electronic assembly shop for the maintenance of waste printed circuit boards. A special anode (chemically reactive anode, such as graphite) is wrapped in an absorbent material (cotton swab), which is used to bring the plating solution to where it is needed to be plated.