PCB News - What are the common problems in PCB design?

What are the common problems in PCB design?

What are the common problems in PCB design? Let's take a look at the following:

1. Pad overlap

1. The overlap of the pad means the overlap of the hole. The reason is that the drill is broken and the hole is damaged by drilling multiple times in one position during the drilling process.

2. The two holes on the multilayer board overlap.

Second, the abuse of the graphics layer

1. Some useless connections are made on some graphics layers.

2. The design requires fewer lines.

3. Violation of traditional design, such as component surface design on the bottom layer and welding surface design on the top layer, causing inconvenience.

3. Random placement of characters

1. The patch pad of the character cover brings inconvenience to the on-off test of the circuit board and the welding of components.

2. The character design is too small, making screen printing difficult. If it is too large, the characters will overlap and be difficult to distinguish.

Fourth, the setting of the single pad aperture

1. Single-sided pads are usually not drilled. If the drilling needs to be marked, the hole diameter should be designed to be zero.

2. Single-sided pads should be specially marked if they are drilled.

Fifth, a drawing board with filling blocks.

When the solder resist is applied, the area of the filler block will be covered by the solder resist, which makes it difficult to solder the device.

6. The formation of electricity is the flower cushion and connection

Because the power supply is designed with a flower cushion pattern, the ground layer is opposite to the image on the actual printed board, and all connection lines are isolated lines. When drawing isolation lines for several groups of power supplies or types of grounding, no gap should be left to short-circuit the two groups of power supplies or block the connection area.

Seven, the definition of processing level is not clear

1. The single board is designed on the top layer. If there is no description on the front and back, the manufactured panel may be equipped with devices instead of soldering.

2. When designing a four-layer board, use the top, middle 1 layer, middle 2 layers, and bottom 4 layers, but they are not arranged in this order during processing.

8. There are too many filling blocks in the design or the filling blocks are filled with very thin lines.

1. There is a phenomenon of data loss in the lighting drawing, and the data is incomplete.

2. Since the filling block is drawn line by line in the light rendering data processing process, the amount of data generated is quite large, which increases the difficulty of data processing.

9. The pad of the surface mount device is too short.

For too dense surface mount devices, in order to install the test pins, you must use up and down (left and right) staggered positions.

Ten, large area grid spacing is too small

The edges between the same lines that make up the large-area grid lines are too small (less than 0.3 mm), and many damaged films are easily attached to the circuit board after the image is displayed, causing wire breakage.

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

The distance between the large area copper foil and the outer frame should be at least 0.2 mm.

12. The outline frame design is not clear

Some customers have designed contour lines on reserved layers, board layers, top layers, etc. This makes it difficult for circuit board manufacturers to determine which contour line should be dominant.

13. Graphic design is not uniform

When pattern plating, uneven plating will affect the quality.

14. The abnormal hole is too short

The length/width of the special-shaped hole should be ≥ 2: 1, and the width should be greater than 1.0 mm. Otherwise, the drilling machine is easy to break during processing, which will be difficult to process and increase the cost.

The above are the common problems in PCB design, I hope it will help you.