PCSPCB for you to talk about PCB proofing parameters how to choose? PCB punching parameters selection method. PCB proofing refers to the trial production before mass production. The design engineer converts the circuit board design drawings into Gerber files, and then sends them to the PCB board factory to make actual sample boards according to Gerber files to verify the correctness, feasibility and reliability of the circuit design. PCB proofing is more important to clarify the basic parameters such as the type, quantity and size of the plate, and to clarify the conventional process parameters such as solder resistance color and surface treatment method.
PCB punching parameters selection method.
1. Plate type
The choice of PCB board is one of the factors affecting the quality, FR-4(epoxy resin-glass fiber board) is the most commonly used material for PCB production, high strength, heat/fire resistance, chemical resistance, moisture resistance, thermal conductivity, insulation and other advantages gather together, and the board brands mainly have Kingboard, Sheng Yi, South Asia and so on.
The size of the PCB board is normal, not too small, the need for a large PCB board size, can be divided into several pieces of production, and finally spliced combination.
PCS, which is often said in the industry, is the number of units of the board, and the unit of the Mosaic is SET.
2. Number of sub-layers
The number of sub-layers of the board is explained separately, because the number of layers needs to be determined when the PCB is designed, and then the corresponding number of layers is produced according to the design requirements.
According to the number of layers, PCB can be divided into single panel, double-sided layer and multi-layer board. The higher the number of layers, the more difficult the process and the higher the cost.
- Single-layer board is the most basic and simple, suitable for simple circuits;
- Double panel has a top layer, the middle insulation layer, suitable for general complex circuits;
- Multi-layer board is a general term, 4/6 layer board is more commonly used, and the number of layers of multi-layer board is generally even.
3. Conventional process
There are many conventional PCB processes, and the PCB proofing parameters provided below are for reference only.
- Welding color: there are green, blue, black, red, yellow and other colors, but the process production is mostly green, the reason is that the performance of green oil is the best;
PCB board thickness: If there is no special demand, 1.6mm is the most commonly used, and 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm...... To choose from;
The thickness of the copper foil is selected according to the power, which is commonly 1.0oz.
Character color is also known as screen printing color, white is the most common, because it forms a strong contrast with green solder resistance, more clearly seen; Of course, screen printing can also use other colors, but it is recommended to choose a color with high contrast and solder resistance color.
Welding resistance covering, that is, green oil covering, mainly includes through hole window opening, through hole cover oil, through hole plug oil, through hole plug resin.
- Open the window through the hole: open the window where there is a hole, exposing the copper foil at both ends of the hole.
- Through the hole cover oil: do not open the window, green oil covers the copper foil at both ends of the hole.
- Through the hole plug hole: plug the hole, can be green oil, resin, metal, etc.
4. Pad spraying
Pad plating is also known as the surface treatment of PCB board, because the copper solder joint on the circuit board is easily oxidized in the air, resulting in poor contact and other problems, so it is necessary to do surface treatment.
The surface treatment process includes tin spraying, gold sinking, electric gold plating and OSP, and customers can choose a reasonable process according to their needs.
- OSP, organic solderable protective film, the lowest cost PCB surface treatment process.
- Spray tin is divided into lead spray tin and lead-free spray tin, mature technology, low cost.
- Gold sinking, that is, gold plating on the PCB, the whole process of chemical reaction, so it is also called gold. The surface of the board after sinking gold is smooth and the color is stable.
Finally, add the minimum line width/line distance of PCB in the initial design, the answer is that the smaller the difficulty is higher, we can according to the process capacity available to domestic manufacturers.
In fact, there are other special processes in PCB manufacturing, although less used, but there is market demand, so it is classified as a special process, and some process names are special to understand what the process is at a glance, such as goldfinger, blind buried holes, multi-layer special laminated structure, nickel palladium, etc.
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