SMT preliminary simple tutorial（SMT double splice tape）
Introduction to SMT
1. What is SMT?
SMT is the English abbreviation of Surface Mount Technology, which means surface mount technology. SMT is a new generation of electronic groups
Installed technology, is currently the most popular electronic assembly industry, a technology and technology. It will be the traditional electronic components compressed into a volume only
There are a few tenths of the device.
History of
Surface mount is not a new concept, it comes from earlier processes such as paperback and hybrid installation.
Electronic circuit assembly, the initial use of point-to-point wiring method, and there is no substrate. The first semiconductor device is packaged
Use a radial pin to insert it into the through-hole of the monolithic circuit board that has been used for resistors and capacitor packages. 50 years, the surface of the paperback
Installed components used in highly reliable military, 60 years, hybrid technology is widely used, 70 years, by the Japanese consumer electronics products
Ring, passive components are widely used, nearly a decade of active components are widely used.
3.SMT features
Assembly density, electronic products, small size, light weight, the size and weight of the chip components only the traditional cartridge components around 1/10,
After the general use of SMT, electronic products to reduce the volume of 40% to 60%, weight reduction of 60% to 80%.
SMT products, high reliability, anti-vibration ability; solder defect rate is low, high-frequency characteristics of good; reduce the electromagnetic and RF interference.
And easy to achieve automation, improve production efficiency. Reduce the cost of 30% to 50%. Saving material, energy, equipment, manpower, time
And so on.
4.SMT advantage
The pursuit of miniaturization of electronic products, previously used perforation plug-in components can not be reduced;
Electronic products function more complete, the use of integrated circuits (IC) has no perforation components, especially large-scale, highly integrated IC, had
Using surface patch components;
Product batch, production automation, the factory to low-cost high-yield, quality products to meet customer demand and strengthen the market competition
The development of electronic components, the development of integrated circuits (ICs), the multi-application of semiconductor materials, etc.,
Are chasing the international trend of SMT technology show advantages.
5. Several important parameters affecting print quality
① Scraper pressure: Scraper pressure changes, the impact of the printing is significant. Too little pressure, resulting in insufficient amount of solder paste on the printing plate; too
Large pressure, which causes the solder paste to be too thin. The blade pressure is generally set to 0.5Kg / 25mm, in the ideal scraper speed and pressure,
Should just clean the solder paste from the surface of the template. In addition, the hardness of the scraper will also affect the thickness of the solder paste. Too soft scraper will make the solder paste depression,
It is recommended to use a hard scraper or metal knife;
② printing thickness: printing thickness is determined by the thickness of the template, the machine set and solder paste characteristics also have a certain relationship. The template is thick
The degree is closely related to the IC foot. Print thickness of the micro-adjustment, often by adjusting the blade speed and scraper pressure to achieve.