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Jun.2020 09
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What are the precautions for the trend and shape of printed conductors on PCB pads?
介绍
The printed conductors of the circuit board in SMT should be very short. The direction of the printed conductor shall not have sharp bends and acute angles. Copper foil should be reserved for ordinary ground wire as much as possible. In order to increase
细节
The SMT reflow soldering process requires that the pads of the two chip components should be independent pads. When the pad is connected to a large-area ground wire, the cross-laying method and the 45°-laying method should be preferred; the wire drawn from the large-area ground wire or the power line should be longer than 0.5mm and wider than 0.4mm; The wire connected to the pad should be led out from the center of the long side of the pad to avoid a certain angle.
The trend and shape of the printed conductor
(1) The printed conductors of the circuit board in SMT should be very short. So if you can walk the shortest, don’t go complicated. Follow what can be easy not to be complicated, to be short but not long. It is very helpful for the quality control of the PCB circuit board in the later period.
(2) The direction of the printed conductor shall not have sharp bends and acute angles, and the angle of the printed conductor shall not be less than 90°. This is because it is difficult to corrode small inner corners when making the board. At the outer corner that is too sharp, the copper foil is easily peeled off or warped. The best form of turning is a gentle transition, that is, the inside and outside corners are the best radians.
(3) When the electric wire passes between the two gaskets without communicating with them, the maximum and equal distance should be kept with them; similarly, the distance between the wires should be uniform and equal and kept the maximum.
(4) When connecting wires between PCB pads, when the center distance between the pads is less than the outer diameter D of the pad, the width of the wire can be the same as the diameter of the pad; when the center distance between the pads is greater than D, the width of the wire should be reduced. When there are more than 3 pads on the pad, the distance between the wires should be greater than 2D.
(5) Copper foil should be reserved for ordinary ground wire as much as possible.
(6) In order to increase the peel strength of the liner, a production line with no conductive effect can be provided.