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Common drilling holes for PCBs in circuit board factories: through holes, blind holes, and buried holes. The meaning and characteristics of these three holes as following in article.

Generally speaking, the multi-layer PCB board is formed by laminating and pressing a core board and a prepreg. The core board is a hard, specific thickness, two-coated copper plate, which is the basic material for the printed board . The prepreg constitutes the so-called wetting layer, which plays a role of bonding the core board. Although it also has a certain initial thickness, its thickness will change during the pressing process.

Today I'm going to popularize whether PCB board manufacturing should choose immersion gold or HAL(Lead free). If it is relatively simple and the component package is relatively large, we usually recommend customers to make HAL(Lead free) PCB. The advantages of HAL(Lead free) are good solderability, cheaper price, and less susceptible to oxidation than OSP.

Generally, a large area of copper foil is designed on the circuit board for grounding. Sometimes, a large area of copper foil is also designed on the Vcc layer. When these large area copper foils cannot be evenly distributed on the same piece When it is on the circuit board, it will cause the problem of uneven heat absorption and heat dissipation speed. Of course, the circuit board will also expand and contract with heat. If the upper limit of the Tg value has been reached, the circuit board will begin to soften, causing permanent deformation.

Manual soldering of PCB boards is very simple for engineers who often solder, but it may be difficult for people who have not soldered, especially if the soldering is wrong, If you want to remove it, it will be more troublesome. When you encounter some PCBs with poor quality, the chance of the pad falling off is very high.

Negative film of PCB circuit board: It is generally the tenting process we talk about.The chemical solution used is an acid etching negative film because after the negative film is produced, the desired circuit or copper surface is transparent, and the unnecessary part is black. After exposure through the circuit process, the transparent part is chemically hardened due to the exposure of the dry film resist to light.The subsequent development process will wash away the unhardened dry film, so only the dry film washout is bitten during the etching process Part of the copper foil (the black part of the negative), and the dry film is not washed out. It belongs to the line we want (the transparent part of the negative).

In the surface treatment of circuit boards, there is a very common process called immersion gold PCB. The immersion gold process is to make the nickel-gold plating with stable color, good brightness, smooth plating and good solderability on the surface of the printed circuit board of the PCB. After adding sunken gold, the PCB shows a golden yellow color. This color is more golden than the gold-plated color. Because the sunken gold is brighter and more beautiful. It also looks very comfortable, and customers will be more satisfied with our products. The characteristics are summarized as follows in article.

Everyone who is engaged in the PCB manufacturing industry knows that copper-clad boards are covered with a piece of copper foil on the insulating material, and then baked. If you look closely, you will see that there will be shrinkage during the drying process, and stress in all directions will be generated. This is the source of the stress. Secondly, the purpose of the baking board before the PCB drilling is actually dehumidification. In order to remove the moisture in the board and reduce the internal stress; there is also printing resistance welding after the pressing, including characters, etc., need to be baked. There is also a baking platen process before shipping and packaging, which is also to remove moisture. The baked plate has a relatively large improvement in warpage.

In double-sided and multi-layer PCB boards, in order to connect the printed wires between the layers, a common hole is opened at the intersection of the wires that need to be connected, but pay attention to the outer diameter of the hole and the size of the hole This is a via, also known as a metalized hole. There are three types of via processing methods: via solder mask opening, via ink cover, and via ink plugged. Let's talk about the definition of via plug ink.

We all know that the solder pad refers to the part of the board that needs to be coated with green oil, but in fact this solder mask layer uses a negative output, so after the shape of the solder mask layer is mapped onto the board, it is not the green oil solder mask Instead, the copper skin was exposed. Generally, in order to increase the thickness of the copper skin, the solder resist layer is scribed to remove green oil. The role of solder mask in controlling soldering defects during the reflow soldering process is important, and PCB designers should minimize the spacing or air gaps around the pad features.

The through-hole component wave soldering process requires the through-hole component package to withstand the high temperature and time of the reflow furnace. The following figure is a connector that can be used for through-hole reflow soldering. In addition, there are certain requirements for pin formation . Specific requirements are as follows in article.

In the actual production of the current SMT processing plant, although AOI has higher efficiency than manual visual inspection, after all, the results are obtained through image acquisition and analysis processing, and the related software technology of image analysis processing has not yet reached the level of the human brain. Therefore, in smt patch processing, some special circumstances, such as AOI misjudgment and missed judgment, are inevitable. At present, the main problems of AOI's inspection after smt patching are as instruction in the article.

Among the key applications of PCBs today, automotive PCBs occupy an important position. PCB copy board, but due to the special working environment, safety and high current requirements of the car, it has higher requirements on PCB reliability and environmental adaptability, and the types of PCB technology involved are also wide, which is for PCB companies. It is a challenge; for manufacturers who want to develop the automotive PCB market, more understanding and analysis of the new market is needed.

 First: We can distinguish the printed circuit board is good or bad from the appearance (in general, the appearance of the PCB circuit board can be analyzed and judged through three aspects; Second: high-quality PCB circuit boards need to meet the following requirements as listed in the article.

Proper layout of PCB components in chip processing is the basic premise for designing high quality PCB patterns. The requirements for component layout mainly include five aspects of installation, stress, heat, signal and appearance.