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PCB design of DFM some matters needing attention
1100 0 Dec 03.2013, 17:45:00

1. Board some welding plate easy to fall off; For example: brush weld bonding pad

Brush as shown, the welding pad when debugging or the backend maintenance most on the left side of the pad is very easy to fall off, is the whole board is discarded, the reasons for this problem is: the welding plate and the connection area is too big, so heat quickly, quickly cooling in the welding process, in the process of pulling naturally easy to fall off.

Solution: 1) on the similar pad blind hole, make its connection with the adjacent layer, increase the board on the pulling force. 2) similar brush welding welding plate with tears go line, with 1). 3) library, the window of the bonding pad made among "narrow", make the green oil pads produces certain pulling force.

Battery holder, or relative larger pad (welding)

As shown above, the design for the first time, the battery holder of the cathode is in the middle of the welded plate adopt cross thin neck line connection, the actual welding, welding plate is easy to fall off, improvement measures to connect with.

There are many similar situation, readers need to extrapolate, the other is not here.

2. The grounding pad cross connection, or even the welding

As shown in the figure highlighted in two to solder, actual go easily with signal beside the foot when welding welding, it is associated with resistance welding open the window to expand its welding plate, readers analysis on its own.

3. The middle of the grounding pin open stencil QFN do best when handling or patch to virtual welding.

4. Key holing best stagger center if in the center of the button, because the center contact friction is bigger, after a long time may cause button.

5. The back metallization positioning hole is best not to dew dew copper or less, metallization have to general positioning hole to open the tin, if on the back of the dew copper, tin, may to the other side, cause assembly problems.

6. The whole plate printing label is clear.

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