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Generally, in the SMT chip processing process, the viscosity of the solder paste used is 180~200Pa/s. If the viscosity of the solder paste is low, the solder paste will be too thin. At this time, it may be that there will be process problems such as collapse, false soldering, tombstones, tin beads, insufficiency, and empty BGA in printing. So how to detect and control the viscosity of solder paste.
1. The viscosity of the solder paste will increase with the decrease of the workshop temperature. Generally, it is recommended that the workshop temperature is 25 plus or minus 2.5 degrees, and it is best not to exceed 28 degrees. Conversely decrease;
2. If the diameter area of the solder paste is larger when it is printed on the stencil, the viscosity will be higher, otherwise the viscosity will be lower. We usually choose the solder paste rolling diameter of 10-15;
3. The higher the solder paste printing speed, the lower the viscosity.
Since the viscosity of the solder paste is inversely proportional to the angular velocity of the movement, we can adjust the squeegee speed appropriately. At the same time, the viscosity of the solder paste will decrease with the mixing of the solder paste. Stop the mixing and let it stand for a while, and the viscosity of the solder paste will recover;
4. The angle of the squeegee will also affect the viscosity of the solder paste. The larger the angle, the greater the viscosity, and vice versa. Two types of squeegees, 45 degrees or 60 degrees, are usually used.
What is SMT placement skills? What are the advantages of using SMT patch skills? How to implement SMT placement skills? This article will explain one by one.
1. What is SMT placement skills?
SMT placement skills are also called SMT placement skills or SMT device skills. The full name of SMT is Surfaxd Mounting Technolegy. SMT skills are a new generation of high-tech electronic placement skills and a new type of industrial manufacturing skills and processes. Its main function is to quickly install electronic components on the PCB through placement technology to achieve high power., High density, high reliability, low cost and other production process automation.
2. What are the advantages of using SMT patch skills?
As the market with fierce competition becomes more and more fierce, it is necessary to make product costs in order to make a living., Labor cost, production rate, product quality advantages. SMT placement skills can effectively improve production power, reduce costs, and ensure quality.
(1) Improve productivity and reduce labor and product costs
The biggest feature of SMT patch technology is the completion of automation, which can effectively improve production power and save data., Energy, human beings, time, etc., effectively reducing costs by 30%-50%. The rise of SMT placement skills has made electronic assembly easier. As a result, many electronic products are being upgraded, integration levels are improving, and prices are getting lower and lower.
(2) Guarantee product quality and improve reliability
SMT placement skills can ensure that the solder joint defect rate of electronic products or components is low., High frequency characteristics. Therefore, electronic components or electronic products using SMT chip technology have a high degree of vibration resistance., High reliability, reduce electromagnetic and radio frequency interference.
(3) The basis for the change of electronic products to miniaturization
Nowadays, the device density of electronic products is getting higher and higher., The volume is getting smaller and smaller., The weight is getting lighter and lighter. The size and weight of the chip component is only about 1/10 of that of the traditional plug-in component, or even very small. After selecting SMT patch technology, the volume of electronic products can be reduced to 40%~60%, and the weight can be reduced to 60%~80%.
