PCB News - Some techniques of pcb proofing

Multicolored coats for PCB proofing PCB
Our first impression of a computer board is probably its color. In addition to the most common green and brown, there are blue, red, black, purple, etc., so what is the meaning of these colors? To answer this question, Let's first think about why other copper wires on the PCB are not tinned. Except for the soldering pads and other parts on the PCB, the surface of the remaining parts has a layer of solder mask that is resistant to wave soldering, which is used to prevent wave soldering. It has the advantages of bridging, improving welding quality and saving solder. It is also a permanent protective layer for printed boards, which can prevent moisture, corrosion, mildew and mechanical abrasion. Most of the solder mask is green, so In the PCB industry, solder mask oil is often called green oil. The color of PCB is actually the color of solder mask oil. If solder mask oil is added to other chemical raw materials, its color can be changed, but the color is only used for decoration and performance. It has no effect.

Seemingly ordinary details
PCB proofing mounting hole
The mounting holes are the screw holes for fixing the board. If it is not used for grounding, copper foil cannot be used within 5mm. These holes are used for grounding, so there is a circle of copper foil around. In this way, the ground wire of the PCB board passes through the metal screw. Connected to the metal shell of the chassis, it can play a shielding role.
Reference point
PCB proofing boards that use a large number of SMD components are usually very dense, and the pin arrangement of some large-scale integrated circuits is more dense, and the use of automated equipment to place components on the PCB requires very high precision. In order to meet this requirement, The PCB is usually designed with reference points to help automation equipment align the PCB. There are usually global reference points and local reference points on the PCB. The two reference points seen on the diagonal of the entire PCB are the global reference points. Local reference points can be seen on the diagonal of the components of the fine-pitch QFP, TSOP, and BGA packages. With these reference points, all the components can accurately coincide with the design position on the PCB.
How PCB Proofing PCB Is Made
Just take a motherboard and look at it, you may find it incredible, how is such a complicated circuit made into a PCB? To make a PCB, you must first use a special software (such as Protel) to design the circuit schematic diagram, and then import the schematic diagram into the PCB Design software for layout, that is, determine the position of each component on the PCB. After the position is determined, the line drawing tool in the software must be used to connect these components together. These lines are the actual copper foil on the PCB. Connections cannot be crossed at will. Crossing means electrical connections. Only the connections allowed in the circuit schematic can be crossed. Therefore, the copper foil connections on our PCB are all twists and turns, winding around.
After the PCB drawing is designed, it can be processed by the factory.
It can be seen that the manufacture of PCB is not so simple. If it is to manufacture multilayer boards, the processing technology is more complicated and the cost is higher. In fact, PCB accounts for a larger proportion of the cost of computer boards. This is why some boards use a four-layer board design in order to reduce costs.
In general, the design and manufacture of PCB is a complicated science. Even the computer boards produced by those humble small factories on the market are all designed by professional PCB engineers. When you buy a computer board, you may wish to appreciate it first. Let's take a look at the beauty of PCB.