Top ten mistakes of PCB circuit board proof design

1. The definition of processing level is not clear

 

Single-panel design is in the TOP layer. If you do not specify the pros and cons, the board may be made with components and not easy to solder.

 

2. The large area copper foil is too close to the outer frame

 

Large-area copper foil should be at least 0.2mm away from the outer frame. When milling the copper foil, it is easy to cause the copper foil to warp and cause the solder resist to fall off.

 

3. Draw pads with padding

 

Drawing pads with pads can pass DRC inspection when designing the circuit, but it is not possible for processing. Therefore, soldering data cannot be generated directly for pads of the same type. When the solder resist is applied, the pad area will be covered by the solder resist, resulting in devices. Difficult to weld.

 

4. The electrical ground is also a flower pad and a connection

 

Because it is designed as a flower pad power supply, the ground layer is the opposite of the image on the actual printed board. All connections are isolated lines. Care should be taken when drawing several sets of power supplies or several types of ground isolation lines. A short circuit in the power supply should not cause the connection area to be blocked.

 

5. The characters are scattered

 

SMD solder pads for character cover pads, which bring inconvenience to printed board on-off test and component welding. Character design is too small, making screen printing difficult, and too large will make characters overlap each other and difficult to distinguish.

 

6. Surface mount device pad is too short

 

This is for the continuity test. For too dense surface-mount devices, the distance between the two feet is quite small, and the pads are quite thin. The test pins must be staggered up and down. For example, the pad design is too short. Affects the device installation, but can make the test pin staggered.

 

7.Single-sided pad aperture setting

 

Single-sided pads are generally not drilled. If drilling is required, the hole diameter should be designed to be zero. If a numerical value is designed, when the drilling data is generated, the hole coordinates appear at this position, and a problem occurs. Single-sided pads, such as drilled holes, should be specially marked.

 

8.Pad overlap

 

During the drilling process, the drill will be broken due to multiple drilling in one place, resulting in hole damage. The two holes in the multilayer board overlapped, and after drawing the negative, it appeared as an isolation disk, which caused scrap.

 

9.There are too many padding blocks in the design or the padding blocks are filled with very thin lines

 

The light drawing data is lost, and the light drawing data is incomplete. Because the filling blocks are drawn with lines one by one when processing light drawing data, the amount of light drawing data generated is quite large, which increases the difficulty of data processing.

 

10.Graphic layer abuse

 

I made some useless connections on some graphics layers, but originally it was a four-layer board but designed more than five layers of circuits, which caused misunderstanding. Violates conventional design. The graphics layer should be kept complete and clear when designing.

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