PCB circuit board with insulating board as base material, cut to size, at least accompanied by a conductive pattern and cloth with holes, such as hole components, fastener holes, metallized hole, used to replace the previous device electronic components of the chassis and achieve the mutual connection between the electronic components. The design process of PCB circuit board is generally divided into three main parts, which are pre treatment, middle processing and post processing. Pre work is mainly to enter the preparation work before the PCB circuit board, the processing is the key to the whole circuit board design, after processing is the final work of the output circuit board. Today, with the development of electronic industry, with the development of electronic products, the trend of light, thin and small.
The application scope of the circuit board is more and more wide, explain the choice of material of PCB circuit board today:
1, gold plate
Gold plate process cost is all PCB circuit board in the highest, but at present all existing PCB plate most stable, is most suitable for use in lead free process of the PCB board, especially in some of the high price or need high reliability of electronic products have suggested using the PCB board as base material.
This kind of PCB substrate is easy to pollution, scratch, plus process (FLUX) will change the color of the case, the domestic manufacturers do not use this process, the cost is relatively high.
3, OSP board
OSP process lowest cost, easy to operate, but the process must assemble factory modified equipment and process conditions and less heavy so popular degree is poor due to, use the PCB board, after high temperature heating and pre coated in the protective film on the pad is bound to be a failure in, which led to reduce solder, especially when PCB circuit board through the secondary reflow after more serious, so if process also need to again after a dip process, at this time dip side will face welding on the challenges.
4, gold plate
Such a PCB (printed circuit board) the biggest problem is the "black pad" (the blackpad could), so in lead-free process has many manufacturers agree not to use, but domestic manufacturers most of the use of the process.
Because of the low cost, solderability, good reliability, compatibility of the strongest, but this kind of welding characteristics of good HASL because it contains lead, so lead-free process cannot be used. The "tin silver copper HASL" because most of them are not using this process, the characteristics of data from difficulties.
Although "silver" itself has a strong mobility, resulting in leakage occurs, but today's "leaching silver" is not the past pure silver, but with organic co deposition of organic silver "therefore has been able to conform to the needs of future lead-free process, the welding of the life is higher than the OSP board more for a long time.