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analysis of material temperature.
The convection rework station which can save many temperature curves is directed by the
approximate situation of PCB heating. The more precise method is to connect a K sensor to the
PCB to detect the temperature. What's more, the final form of process control is to detect the
welding points in the process, or to detect the reflow points. Look at the following picture:
Infrared reflow oven and repair sets are not new to the world. However,
because the physical effect is limited, infrared ray has lost some market. When the
heat radiation distribute evenly, objects in different colors absorb and reflect heat
radiation unevenly.
The purchase decision of Array Package Rework Station should start from the
reliable technology. It is important to control the process. ZM-R580B is easy to
operate and very useful in the soldering of SMD, TH and plastic. It can make the
most profit out of the least investment.
a. Compatibility of components.
Lead-free soldering is more and more popular. Eutectic solder ball in still the
standard choice in USA. Components manufacturers consider the using of lead-free
balls as the standard.
b. Setting of temperature difference.
The temperature difference on the surface of components is a must factor to be
considered in quality rework and assembly. Increment of 10
Temperature difference of component from top to bottom is another important factor.
c. Control of temperature curve
To avoid brittle rupture in welding points, the temperature should be better controlled, especially
the heating of PCB bottom. Heating board can't change the temperature in a short time, so it can't
be used in lead-free solder process.
2. Setting and adjustment of temperature curve
Setting of temperature curve is the first and most important step of BGA
rework. Compared with reflow temperature curve, the control of temperature in
rework process is more strict, because in normal reflow oven, the temperature loss
id nearly zero. But in the rework process, the PCB is usually exposed in the air, we
heat the components respectively. In this way, there is much loss of temperature.
But we loss can't be made up only by heating. The reasons are as follows: one is
that over heating will damage the components. The other is that the uneven heating
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can be accepted.
℃
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