Advantages of PCBA SMT patch processing technology
With the development of electronic industry, the surface assembly technology of SMT is more mature, and the function of the equipment is also improving. The SMT patch processing technology has gradually replaced the traditional intercalation technology. It has become one of the most popular technology in electronic assembly industry. "Smaller, lighter, denser, better" is the biggest advantage of SMT chip processing technology. It is also the requirement of high integration and miniaturization of electronic products.
SMT patch process: first of all, it should coat solder paste on the pad of printed circuit board, then sticking the metallized terminal or pin of the component onto the solder paste accurately. Then the printed circuit board and the components are put together in the reflux soldering furnace to heat the solder paste until the solder paste melts. After cooling the solder paste solidifies, the connection between the components and the printed circuit is realized.
SMT patch processing is made of flaky components with high reliability, small and light components. So it has strong anti-vibration ability, and adopts automatic production with high reliability. Generally poor solder joint rate less than 10/1000000.It can ensure low defect rate of solder joint in electronic products or components. At present, almost 90% of electronic products adopt SMT process.
The volume of SMT patch components is only about 1/10 of the traditional components, and the weight is only 1/10 of the traditional ones. Usually, using SMT technology can reduce the volume of electronic products by 40% and reduce the quality by 60%. The area and weight are greatly reduced. The SMT patch processing assembly element grid developed from 1.27MM to the current 0.63MM grid, and it reached the 0.5MM grid. The assembly density can be higher by using the through hole installation technology to install the components.
Because chip components are firmly attached, devices are usually no lead or short lead. The influence of parasitic inductance and parasitic capacitance is reduced, and the high frequency characteristic of the circuit is improved. The maximum frequency of the circuit designed by SMC and SMD is 3 GHz, while the chip element is only 500 MHz, which can shorten the transmission delay time. It can be used for circuits with clock frequency above 16MHz. With MCM technology, the high-end clock frequency of the computer workstation can reach 100 MHz, and the additional power consumption caused by parasitic reactance can be reduced 2-3 times.
In order to achieve automation of the perforated mounting PCB, it is necessary to expand the area of the original PCB by 40%.So that the plug head of the automatic plug-in can insert the components. Otherwise, there is not enough space gaps, it will damage the parts. Automatic mounting machine adopts vacuum nozzle suction device, vacuum suction nozzle is smaller than element shape, but it increases installation density. In fact, small components and fine-spaced QFP units are produced by automatic placement machine to realize the whole line automatic production.
Fifth, reduce costs, reduce expenses
(1) the area of PCB is 1 / 12 of that through hole technology. If the PCB is installed with CSP, its area will be decreased by a large margin;
(2) The number of boreholes on the PCB is reduced, and the cost of reworking is saved.
(3) Because the frequency characteristic is improved, the circuit debugging cost is reduced.
(4) Because of the small size and light weight of the chip components, the cost of packaging, transportation and storage is reduced.
Using SMT patch processing technology can save material, energy, equipment, manpower, time, etc.
