PCB Horizontal Electroplating Process for High-Precision Circuit Boards (3)

According to the characteristics of horizontal electroplating, it is an electroplating method in which the way of placing the printed circuit board is changed from vertical to parallel plating liquid level. At this time, the printed circuit board is the cathode, and some horizontal electroplating systems use conductive clips and conductive rollers for the supply of current. From the point of view of the convenience of the operating system, it is more common to use the supply method of roller conduction. In addition to being the cathode, the conductive rollers in the horizontal electroplating system also have the function of conveying the printed circuit board. Each conductive roller is equipped with a spring device, the purpose of which can be adapted to the needs of electroplating of printed circuit boards (0.10-5.00mm) of different thicknesses. However, during electroplating, the parts in contact with the plating solution may be plated with a copper layer, and the system cannot operate for a long time. Therefore, most of the current horizontal electroplating systems are designed to switch the cathode to an anode, and then use a set of auxiliary cathodes to electrolytically dissolve the copper on the plated rollers.

For maintenance or replacement purposes, the new plating design also allows for easy removal or replacement of wear-prone areas. The anode is made of an array of insoluble titanium baskets that can be adjusted in size, which are placed on the upper and lower positions of the printed circuit board, and are filled with 25mm diameter spherical, 0.004-0.006% soluble copper, cathode and anode. The distance between them is 40mm.

The flow of the plating solution is a system composed of a pump and a nozzle, which makes the plating solution flow rapidly in the closed plating tank, alternately back and forth, and up and down, and can ensure the uniformity of the plating solution flow. The plating solution is sprayed vertically to the printed circuit board, forming a wall jet eddy current on the surface of the printed circuit board. Its ultimate purpose is to achieve rapid flow of the plating solution on both sides of the printed circuit board and through holes to form eddy currents. In addition, a filter system is installed in the tank, and the filter mesh used is 1.2 microns to filter out the granular impurities generated in the electroplating process to ensure that the plating solution is clean and pollution-free.

In the manufacture of horizontal electroplating systems, the ease of operation and automatic control of process parameters should also be considered. Because in the actual electroplating, with the size of the printed circuit board, the size of the through hole diameter and the required copper thickness, the transmission speed, the distance between the printed circuit boards, the size of the pump horsepower, the nozzle The setting of process parameters such as the direction of the copper and the current density, etc., all need to be tested, adjusted and controlled in order to obtain the thickness of the copper layer that meets the technical requirements. It must be controlled by a computer. In order to improve the production efficiency and the consistency and reliability of high-grade product quality, the pre- and post-processing (including plated-through holes) of the through holes of the printed circuit board are based on the process procedures to form a complete horizontal electroplating system, which can meet the requirements of new product development and launch. needs.