For PCB board, I believe that you are no stranger to electronics workers. It is an important part of modern electronics. It is also indispensable. How much do you know about its production process? Let's take a look at it.
The substrate of the PCB itself is made of a material that is insulated and hard to bend. The thin circuit material that can be seen on the surface is copper foil. The original copper foil covers the entire PCB. During the manufacturing process, part of the wiring is etched away, and the remaining part becomes a mesh-like small line. It is.
These lines are called wires or wires and are used to provide electrical connections to the parts on the PCB. Usually the color of the PCB board is green or brown, which is the color of the solder resist paint. It is an insulating protective layer that protects the copper wire and prevents the parts from being soldered to the wrong place.
The PCB manufacturing process begins with a PCB "substrate" made of glass epoxy (Glass Epoxy) or similar material. The first step in the fabrication is to light-draw the wiring between the parts by "subtractive transfer" to "print" the printed circuit board of the printed circuit board onto the metal conductor.
The trick is to lay a thin layer of copper on the entire surface and remove the excess. If a double panel is made, the substrate of the PCB will be covered with copper foil on both sides. The multi-layer board can be used to "press" the two double-sided panels with special adhesives.
Next, you can drill and plate the required components on the PCB. After drilling the machine equipment according to the drilling requirements, the hole must be plated (Plated-Through-Hole technology, PTH). After metal treatment inside the hole, the internal layers can be connected to each other.
Before starting the plating, the debris in the hole must be removed. This is because the resin epoxy will have some chemical changes after heating, and it will cover the inner PCB layer, so it must be removed first. Both the removal and plating operations are done in the chemical process. Next, it is necessary to cover the solder resist (solder resist ink) on the outermost wiring so that the wiring does not touch the plating portion.
Then, the various component markings are printed on the circuit board to indicate the position of each part. It cannot cover any wiring or gold fingers, otherwise it may reduce the solderability or the stability of the current connection. In addition, if there is a metal connection, the “golden finger” part is usually plated with gold, so that a high-quality current connection can be ensured when inserted into the expansion slot.
Finally, it is tested. Test the PCB for shorts or open circuits and test it optically or electronically. Optical scanning is used to find defects in each layer, and electronic testing is usually done with a Flying-Probe to check all connections. Electronic tests are more accurate in finding short circuits or open circuits, but optical tests can more easily detect problems with incorrect gaps between conductors.
These are the PCB board production processes. You must understand the things you want to do in this job. Be careful in your usual work, so that you will not bring losses to you and the company.
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