The engineering model patch is a kind of electronic assembly technology, which originated in the 1960s. It was originally developed by IBM in the United States and gradually matured in the late 1980s. This technology is to mount electronic components, such as resistors, capacitors, transistors, integrated circuits, etc., on a printed circuit board, and form electrical connections by soldering.Engineering model patchThe components used are also referred to as surface mount components. The biggest difference from through-hole insertion technology is that surface mounting technology does not need to reserve corresponding through holes for component pins, and the component size of surface mounting technology is much smaller than that of through-hole insertion technology. By applying surface mount technology, the overall processing speed can be increased, but due to the miniaturization of parts and the increase in density, the risk of circuit board defects increases. Therefore, in the circuit board manufacturing process of any surface mount technology, error detection has become A necessary part.
What are the advantages of engineering model patch processing technology:
1. High reliability and strong anti-vibration ability
The engineering model patch processing uses chip components, which have high reliability. The components are small and light, so they have strong anti-vibration ability. It adopts automated production and has high mounting reliability. The general defective solder joint rate is less than 10 parts per million. Wave soldering technology is one order of magnitude lower than that of through-hole plug-in components, which can guarantee low defect rate of solder joints of electronic products or components. At present, almost 90% of electronic products adopt SMT process.
Second, electronic products are small in size and high in assembly density
The volume of the SMT components of the engineering model is only about 1/10 of the traditional plug-in components, and the weight is only 10% of the traditional plug-in components. Usually, the use of SMT technology can reduce the volume of electronic products by 40%~60% and the quality by 60%~ 80%, the occupied area and weight are greatly reduced. However, the grid of components for the assembly of the engineering model patch processing has developed from 1.27MM to the current 0.63MM grid, and some even reached 0.5MM grids. Using through-hole mounting technology to install components can make the assembly density higher.
3. Good high frequency characteristics and reliable performance
Because the chip components are firmly mounted, the devices are usually leadless or short leads, which reduces the influence of parasitic inductance and parasitic capacitance, improves the high-frequency characteristics of the circuit, and reduces electromagnetic and radio frequency interference. The maximum frequency of the circuit designed with SMC and SMD is up to 3GHz, while the chip component is only 500MHz, which can shorten the transmission delay time. It can be used in circuits with a clock frequency above 16MHz. If the MCM technology is used, the high-end clock frequency of the computer workstation can reach 100MHz, and the additional power consumption caused by parasitic reactance can be reduced by 2-3 times.
Fourth, improve productivity and realize automated production
Engineering model patchAt present, the perforated mounting printed board needs to be fully automated, and it is necessary to expand the area of the original printed board by 40%, so that the insertion head of the automatic plug-in can insert the component, otherwise there is not enough space gap, and the part will be damaged. . The automatic placement machine (SM421/SM411) uses vacuum nozzles to suck and release the components. The vacuum nozzle is smaller than the component shape, which increases the installation density. In fact, small components and fine-pitch QFP devices are produced using automatic placement machines to achieve full-line automated production.
Five, reduce costs, reduce expenses
(1) The use area of the printed board is reduced, and the area is 1/12 of the through-hole technology. If the CSP is used for installation, its area will be greatly reduced;
(2) The number of drilling holes on the printed board is reduced, saving repair costs;
(3) Due to the improvement of frequency characteristics, the cost of circuit debugging is reduced;
(4) Due to the small size and light weight of chip components, packaging, transportation and storage costs are reduced;
The use of engineering model patch processing technology can save materials, energy, equipment, manpower, time, etc., and can reduce costs by 30% to 50%.
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