一. Finger row electroplating
In PCB proofing, rare metals are plated on board edge connectors, board edge protruding contacts or gold fingers to provide lower contact resistance and higher wear resistance, which is called finger row plating or protruding partial plating. Its process is as follows:
1) stripping the coating to remove the tin or tin-lead coating on the protruding contacts;
2) Rinse with water;
3) Scrub with abrasives;
4) The activation is immersed in 10% sulfuric acid;
5) The thickness of nickel plating on the protruding contacts is 4-5um;
6) Wash and remove mineral water;
7) Gold impregnation solution treatment;
8) Gold plating;
9) cleaning;
10) drying.
二. Through-hole plating
There are many ways to build a layer of electroplating that meets the requirements on the wall of the substrate drilled hole. This is called hole wall activation in industrial applications. The commercial production process of printed circuits requires multiple intermediate storage tanks. A slot has its own control and maintenance requests. Through-hole plating is a necessary follow-up manufacturing process of the drilling process. When the drill bit drills through the copper foil and the substrate below it, the heat generated causes the insulating synthetic resin that constitutes the matrix of most substrates to condense. The condensed resin and other drilling debris Accumulated around the hole, coated on the newly exposed hole wall in the copper foil, the condensed resin will also leave a layer of thermal axis on the substrate hole wall; it shows poor adhesion to most activators , which requires the development of a class of technologies similar to stain removal and etch-back chemistries.
A method that is more suitable for PCB proofing is to use a specially designed low-viscosity ink, which has very strong adhesion and can be easily bonded to most thermally polished hole walls, thus eliminating backlash. eclipse this step.
三. Roller linkage selective plating
The pins and pins of electronic components, such as connectors, integrated circuits, transistors and flexible printed circuits, are selectively plated to achieve good contact resistance and corrosion resistance. This electroplating method can be manual or automatic. It is very expensive to selectively plate each pin individually, so batch welding must be used. In the selection of this electroplating method, first of all, a layer of resist film is coated on the part of the metal copper foil board that does not require electroplating, and only the selecte copper foil is electroplated.
四. Brush plating
Brush plating is an electro-deposition technique that only electroplates a limited area without any effect on other parts. Usually, rare metals are plated on selecte parts of the printed circuit board, such as areas such as board edge connectors. Brush plating is used more often when repairing scrap circuit boards in electronics assembly shops.
