Know what electronic assembly in processing design layout
Electronic assembly processing on the layout, circuit board size is too large, although the welding is easy to control, but the printing lines long, impedance increases, anti-noise ability, cost increase;
After hours, the heat dissipation is reduced, the welding is not easy to control, susceptible to interference between adjacent lines, such as PCB electromagnetic interference, and so on and so forth.
Therefore, must optimize PCB design: shorten the connection between the high frequency components, reducing EMI interference.
Weight big (
Such as more than 20 g)
Components, should with bracket, then welding.
Heating elements shall be taken into account the cooling problem, prevent components surface has larger Δ T defects and rework, thermal element should be far away from heat source.
Parallel arrangement of components as possible so that not only beautiful and easy to welding, suitable for mass production.
Circuit board design for 4:3 rectangles.
Wire width don't mutation to avoid wiring discontinuity.
Electronic assembly processing plastic parts is not in accordance with the planned shape forming, warping, poor welding formation, if parts have uniform reduced rate, deformation of plastic parts on the scale, will only and won't present the scene of a warp, however, should you want to get to the low to shorten or even shorten is actually an extreme messy and hard to work, therefore, circuit boards and yuan equipment in welding will attack the scene of a warp that will cause because of the deformation and stress present virtual welding in the welding process or short circuit of attack.
Usually, warping because imbalance between the upper and lower part temperature of the circuit board formed, but about the big print circuit board, attack warp factor and perhaps because of the circuit board itself weight drop and cause.
To check the insulation materials in advance before welding, should not present burnt, burning, deformation, cracks, such as welding is not allowed to spoil or damage to the components.
Soldering temperature should be control in at 260 ℃, usually not too high or too low, otherwise it will affect the welding quality.
Circuit board for a long time when heated, copper foil easy to fall off inflation and, therefore, should avoid to use large area of copper foil.
Welding time usually operate within 3 s.
For the large heat capacity such as multilayer welding, all welding process can be controlled within 5 s;
For integrated circuit and heat sensitive components of weldment, whole process should not be more than 2 s.
If the rules in the moment of welding is good, should be the solder joint rewelding after cooling, such as from the beginning of welding welding at the time of the solder joint quality specifications should be with a specification.
Obviously, because the soldering iron power, solder heat capacity difference, such as elements, practice to grasp the welding temperature, no chapter to follow, it is necessary to detailed conditions treated in detail.