Electroplating equipment What are the unique methods of electroplating

There are four unique electroplating methods in the production of circuit boards, which are row type electroplating equipment, through hole electroplating, roller linked selective plating and brush plating. This article introduces these four unique methods in detail.

1. Finger plating equipment

In the electroplating process, it is often necessary to plate rare metals on the edge of the plate joint. The golden finger provides low contact resistance and high wear resistance.

In electroplating, gold is also often plated on the protruding contact of the board edge connector whose inner layer is nickel. The protruding part of the gold finger or the board edge is manually or automatically plated. At present, the gold plating on the contact plug or gold finger has been replaced by lead plating and button plating.

2. Through hole plating

In through-hole electroplating, there are many methods to establish a satisfactory plating layer on the hole wall drilled on the substrate, which is called hole wall activation in industrial applications. The commercial production process of its printed circuit requires multiple intermediate storage tanks, and each storage tank has its own control and maintenance requirements.

When the drill bit passes through the copper foil and its underlying substrate, the hot melting insulating synthetic resin is generated, the insulating synthetic resin that forms the matrix, and the molten resin and other drill bits are stacked around the hole.

In fact, this is harmful to the subsequent electroplating surface. The melted resin will also leave a layer of hot box on the hole wall of the substrate, which shows poor adhesion to most activators. This requires the development of another technology similar to the chemical action of stain removal and corrosion back: oil ink!

Ink is used to form a high adhesion and high conductivity coating on the inner wall of each through hole. In this way, it does not need to use multiple chemical treatment processes. Only one application step is needed, followed by thermal curing. It can form a continuous coating on the inner side of all hole walls. It can be directly plated without further treatment. This kind of ink is a resin based material, which has a strong adhesion and can be easily bonded to most of the thermally polished hole walls, thus eliminating the step of back etching.

3. Reel linked selective plating

In order to obtain good contact resistance and corrosion resistance, pins and pins of electronic components are selected, such as connectors, integrated circuits, transistors and flexible printed circuits.

This electroplating method can use either manual electroplating production line or automatic electroplating equipment. It is very expensive to select and plate each contact pin separately, so it must be welded in batches. In electroplating production, the two ends of the rolled metal foil with the required thickness are usually punched, cleaned by chemical or mechanical methods, and then selectively used such as nickel, gold, silver, rhodium Button or tin nickel alloy, copper nickel alloy, nickel lead alloy, etc.

4. Brush plating

The last method is called "brush plating": it is an electrodeposition technology, and not all parts are immersed in the electrolyte during the electroplating process. In this electroplating technology, only a limited area is electroplated, and there is no impact on the rest.