With the improvement of product performance, PCB has been constantly updated and developed. The lines are denser and denser, and more components need to be placed. However, the size of PCB not only does not increase but also becomes smaller and smaller.
There are many kinds of PCB drilling technology. Traditional methods are used to make inner blind holes. When pressing multilayer board one by one, two double panels with through-holes are used as the outer layer and then pressed with the inner layer plate without holes, then the glue-filled blind hole will appear. However, when making machine-drilled blind holes, the setting of drill depth is not easy, and the tapered hole bottom affects the effect of copper plating. In addition, the process of making inner blind hole is too long and wastes too much cost, so the traditional method is more and more unsuitable.
Now commonly used PCB microhole technology, in addition to carbon dioxide drilling and laser drilling we introduced before, there are mechanical drilling, photosensitive drilling, laser drilling, plasma etching and chemical etching holes, etc.
Mechanical drilling is made by high-speed machining, the most important of which is the drill bit. The drill bit is generally made of tungsten-Cobalt alloy, which is sintered at high temperature and high pressure with tungsten carbide powder as the matrix and cobalt as the binder. With high hardness and high wear resistance, the hole needed can be drilled smoothly.
Laser hole is the use of carbon dioxide, ultraviolet laser cutting made. Gas, or light, forms a beam with a powerful thermal energy that can burn through the copper foil to create the holes needed.
The principle, like cutting, is to control the beam of light. Plasmas are made up of particles spaced apart at random and constantly colliding, and their thermal motion is similar to that of ordinary gases. Plasma etching hole is mainly used for PCB of resin copper layer, using oxygen-containing gas as the plasma, after contact with copper, will produce oxidation reaction, and then remove the resin material to form the hole.
As mentioned before, if the object remains on THE PCB cannot be cleaned by general methods, chemical cleaning method can be used to make the chemical agent react with the residue and then it can be removed. The same is true for drilling holes. If chemical agents are dropped on the place where drilling is needed, the copper foil and resin can be corroded to form holes.
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