The first is finger row electroplating
It is often necessary to coat a rare metal on a plate edge connector, a plate edge protruding contact or a goldfinger to provide lower contact resistance and higher wear resistance. This technique is called finger row electroplating or projection electroplating. Gold plating is often the inner layer of nickel plate edge connector protruding contact head, gold finger or plate edge protruding part using manual or automatic electroplating technology, the current contact plug or gold finger on the gold plating has been replaced by plating basking, lead, plating button. The process is described as follows:
1) remove the coating to remove the tin or tin-lead coating on the protruding contact
2) rinse with water
3) scrub with abrasive
4) the activation is not diffuse in 10% sulfuric acid
5) the thickness of nickel plating on the protruding contacts is 4-5 microns
6) clean and remove mineral water
7) gold osmotic solution treatment
Second, through hole electroplating
There are a variety of methods can be used to establish a layer of desirable electroplating layer on the hole wall of the substrate drilling, which is called hole wall activation in industrial applications. The printed circuit commercial production process requires multiple intermediate storage tanks, each of which has its own control and maintenance requirements. Hole drilling process of follow-up is necessary electroplating production process, when the drill through the copper foil and the substrate, the heat generated by the most to make plate substrate the insulation of the synthetic resin melt, the molten resin drilling and other debris piled up around the holes, coated in copper foil newly exposed the hole wall, in fact it is harmful to the subsequent plating surface. The melted resin will also leave a layer of hot axis on the substrate hole wall, which shows poor adhesion to most activators, which requires the development of a kind of similar technology to remove stains and corrosion back.
A more suitable method for PCB prototyping is to use a specially designed low-viscosity ink to form a high-adhesion, high-conductivity film covering on the inner wall of each through-hole. This eliminates the need for multiple chemical processes, and requires only one application step, followed by thermal curing, to form a continuous film coating on the inside of all pore walls, which can be electroplated directly without further treatment. 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, so as to eliminate the back erosion of this step.
The third, roller – driven selective plating
Pins and pins of electronic components, such as connectors, integrated circuits, transistors and flexible printed circuits, are selectively plated for good contact resistance and corrosion resistance. This plating method can be done manually or automatically. It is very expensive to choose plating for each pin individually, so batch welding must be adopted. Generally, the two ends of the foil rolled into the desired thickness are punched and cut, cleaned by chemical or mechanical methods, and then selectively electroplated with such metals as nickel, gold, silver, rhodium, button or tin-nickel alloy, copper-nickel alloy, nickel-lead alloy, etc. In the choice of plating this electroplating method, first of all, in the part of the metal copper foil does not need to plating coated with a layer of resistance film, only in the selected part of the copper foil electroplating.
Fourth, brush plating
An alternative method of plating is called brush plating. It is an electrodeposition technique in which not all parts are immersed in the electrolyte during electroplating. In this electroplating technique, only a limited number of areas are electroplated with no effect on the rest. Typically, a rare metal is plated on a selected part of a printed circuit board, such as an area such as a board-edge connector. Brush plating is used more often in electronic assembly plants to repair discarded circuit boards. A special anode (a chemically inactive anode, such as graphite) is wrapped in an absorbent material (a cotton swab) and used to carry the plating solution to the place where it is needed for electroplating.