What are the specific problems of bga heating? What should be done? Datafeng technology one for you to answer
According to the principles of physics, heat can be transmitted in three ways: conduction, convection and radiation. Since BGA repair devices are not in direct contact with specific repair objects, they do not include conduction mode, and mainly rely on the other two ways.
Consider the following preheating and upper heating respectively:
Preheating: By placing it below, two modes of heat conduction, convection and radiation, can be obtained, regardless of whether a blower is used. Convection can rely on the physical phenomenon of hot air rising, radiation should not be affected by gravity conditions, so preheating propagation conditions are good, and the reaction speed is fast. With infrared or ordinary electric furnace, as long as the heating area is enough, reasonable temperature control should be relatively easy to achieve.
1, infrared no wind: because the hot air rises instead of pressing down, can not obtain this conduction, only radiation can work, single conduction, causing lag and difficult to control;
2, hot air: there can be two kinds of infrared heating wind and separate hot air, hot air is forced to add (whether with air pump or fan), is forced to accelerate the convection, easy to control (through wind speed, wind volume) lag effect is small. If there is infrared radiation, it is only auxiliary. Forced convection is actually an indirect conduction, with air as the medium. The practice shows that the air flow control method is better than the infrared method.
If we design and manufacture ourselves we should seriously consider the physical principles, and the factors that we are doing repair on Earth.