In the circuit board plating four special plating method

1. Through-hole plating
There are many ways to build a suitable electroplating layer on the hole wall of the drilling of substrate, which is called hole wall activation in industrial application. The commercial production process of the printed circuit 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 the next layer of heat axis on the hole wall of the substrate, which shows bad adhesion to most activators, which requires the development of a kind of technology similar to the stain removal and corrosion chemistry.
A more suitable way to prototype a printed circuit board is to use a specially designed low viscosity ink to form a high adhesion, high conductivity film on the inner wall of each through hole.In this way, there is no need to use multiple chemical processes. Only one application step, followed by thermal curing, can form a continuous coating on the inside of all hole walls. It can be electroplated directly without further treatment.This ink is a resin-based substance that has a strong adhesive that can be easily attached to most of the heat-polished hole walls without any effort, thus eliminating the step of retracting.

2. Finger plating In PCB production, rare metals are often plated on edge connectors, edge protruding contacts or gold fingers to provide low contact resistance and high abrasion resistance.
The inner plating layer is usually plated with nickel plate edge connector protruding contact head, the gold finger or plate edge protruding part adopts manual or automatic electroplating technology, at present the gold plating on the contact plug or gold finger has been replaced by basking, lead plating and plating button.The process is described as follows:
1) Scrub with abrasives 2) Rinse with washing water
3) Remove the tin or tin-lead coating from the protruding contact
4) The activation is not concentrated in 10% sulfuric acid
5) Clean and remove mineral water 
6) Gold-plated 
7) Gold permeation solution treatment
8) The thickness of nickel plating on the protruding contact is 4-5
9) Cleaning
10) Drying
3.Brush plating
Another method to select plating is called brush plating.It is an electrodeposition technique in which not all parts are immersed in electrolyte during electroplating.In this electroplating technique, only limited areas are electroplated without any effect on the rest.
PCB plating rare metals on selected parts of printed circuit boards, such as edge connectors.Brush plating is used more frequently in the maintenance of abandoned circuit boards in electronic assembly workshops.Wrap a special anode (chemically inactive anode, such as graphite) in a absorbent material (cotton rod) and use it to bring the plating solution to where it is needed.
4.Roller linkage selection plating
The pins and pins of electronic components, such as connectors, integrated circuits, transistors, and flexible printed circuits, are plated to obtain good contact resistance and corrosion resistance.This plating method can be either manual or automatic. It is very expensive to select plating for each pin individually, so batch welding is necessary.Usually, the two ends of the metal foil with the required thickness are punched and cut, cleaned by chemical or mechanical means, and then electroplated continuously with alternative materials such as nickel, gold, silver, rhodium, knobs or tin-nickel alloys, copper-nickel alloys, nickel-lead alloys, etc.
In the selection of plating method, firstly, a layer of inhibitor film is applied to the part of metal foil plate that does not need to be plated, and only the selected part of copper foil is plated.