4 DFM Problems in PCB Design
The design of the printed circuit board is based on the circuit schematic diagram to realize the functions required by the circuit designer.
The design of the printed circuit board mainly refers to the layout design, and the layout of external connections needs to be considered. Excellent layout design can save production costs and achieve good circuit performance and heat dissipation performance.
Acute Angle
Sharp angles are sharp or odd angles on copper components in a printed circuit board that can cause acid build-up during the PCB creation process. This problem occurs before the washing process, and the sharp angles cause residual acid to get trapped in these areas and not be able to be removed. Eventually, the copper components needed for the Gerber files contained on the board begin to corrode, causing the copper wires to “break” or disappear.
Copper Bar
The solder mask is very important for PCB design because the scribe lines of the etch traces are very fine and the pins are very closely spaced. The absence of a solder mask can result in large slugs of solder (especially between the pins) during assembly, which can lead to short circuits. In addition, it reduces the corrosion protection of other copper on the outer layer. To prevent these problems, it is important to check the alignment between the pad to the etch line and the outline, and the spacing between solder masks (sidebands). Also, make sure that the solder mask does not cover the pins – our board factory can advise the minimum sideband space and alignment allowed.
Radiator
A heat sink absorbs and dissipates heat from an electronic device through contact with a metal substrate or thermal interface material. If the flux opening in the heat sink is too large, it may cause the device to float off the pad once the solder paste melts. To prevent this, reduce the amount of solder paste you put on the heat sink – don’t use one large flux opening, instead, try dividing it into several smaller flux openings. This will help ensure that the device does not float and bump into other components during the baking process, avoiding short circuits.
Cold Solder Joint or No Solder Wire
It is critical to inspect vias within the pads – if the vias are not placed properly, it can cause solder paste to flow into the vias. This will result in cold solder joints or no real solder connection. We need to determine: the percentage of vias that are allowed in the pad before the vias are required to be plugged. Note: It is the holes in the vias that are causing the problem, not the pads in the vias.
Most software should be able to check for these issues, but if the software we’re using can’t, we have to manually check the design to make sure it meets assembly house standards.
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