With the continuous development of electronic products, circuit boards have become an indispensable part of electronic products. Circuit boards are also an important electronic component, a support for electronic components, and a carrier for electrical connection of electronic components. So what is the PCB circuit board processing flow? The following editor will talk about it in detail.
Circuit board processing flow
1. Data optimization
The optimization of data directly relates to the simplicity of all production; the utilization of materials; the scrap rate; the workload of the production line; so data optimization is the most important core process in the board factory! In addition, the data optimization and The friends of the project design project are very different.
Need to understand the simple principles of design materials; communicate with design engineering; prevent the inconsistency between the products produced and the will of the design requirements! Also consider the layout design; this is closely related to the work of the SMT factory; a good layout design can help SMT save It is not good to go to the situation; at the same time, it can also increase the material utilization rate of the board factory!
The rules for cutting materials are optimized from the engineering data; the work board size and material model of the process issued by the project are different. The large material size of each material model is different. Generally, there are two specifications: 41*49, therefore and 43 *49 inches two kinds There are many types of material models; there are cardboard; fiberglass board; high-frequency board; high TG, etc.; the manufacturers are also not the same as Taiwan Nanya Jiantao Shengyi and PTFE and Rogers board; so be sure to see the design project. Requirements.
The main purpose of drilling is to first connect the holes on the circuit board that need the plug-in to the vias of the circuit; the holes that need to be fixed have been made; the hole diameter is generally between 0.15-6.0 and can be used for CNC drilling; the small hole of 0.1 can only be used Laser drilling (Note: The cost of this process is very high and it is not recommended to use 0.1 Via holes in engineering design); the machines required for drilling are currently commonly used Huaqiang machines and 48,84 system drilling machines; a drilling speed is 16 Between -20 million revolutions; there are also 220,000 revolutions.
4. Shen copper
Copper sinking means to plate the drilled holes with copper. There are currently two processes for sinking copper in China. We will first come to the first one (1: pure copper sinking process: this is the current old process, which can meet the production of all circuit boards. It is required that the copper thickness of the hole can be more than 18um, and the thickness can be 30um to meet the requirements of the excessive current of the circuit board; The second type is the blackening (conductive glue) process. This process is used on circuit boards due to the current low price; but this process has a fatal flaw that the copper thickness of the hole wall is very thin, only 12-16um. Pass UL certification; and can not pass high current and long time work).
The role of etching is to make the wiring of the circuit board; the limit of etching is 2min and usually 3min is suitable; the general board factory likes it above 5min; of course, the more precise the higher the value.
6. Solder mask
Here is to do the solder mask; the role of the solder mask is to make the corresponding color and leak out the position where the window needs to be opened; the difficulty lies in the need to do the IC solder mask and BGA on some high-precision boards; IC solder mask bridges generally require a 6min gap between the bridges to be retained; the difficulty of BGA is that the BGA window is usually a little larger than the line point, and the single side is only about 1min. It is not good for solder mask printing and poor alignment; if If the window is too large, the made BGA points will not be round and the window will be too large, resulting in solder slippage and defective products!
7. Character printing
There are three things to pay attention to when printing characters (the first is the color and ink type; the second is that the printing cannot conflict with the pad and be printed on the pad!
8. Surface treatment
There are many kinds of surface treatment processes (commonly done are lead spray tin, lead-free tin spray, immersion gold, electric gold, OSP, immersion tin, etc.).
9. Exterior processing
There are two ways to process the shape, one is CNC; the other is die punching (CNC has a smooth appearance; mold punching is rough).
The test rack test and flying probe test are usually used for testing; the test rack test efficiency is much higher.
11. The last is visual inspection and packaging and shipment.