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What problems are prone to occur in the circuit board pcb proofing design?

2022-11-16

Everyone knows that pcb board manufacturers will have some design hidden dangers when designing circuit board pcb proofing. question:


1. The pads on the pcb circuit board overlap


The overlap of the pads of the pcb circuit board refers to the overlap of the board holes. During the drilling process, the hole will be damaged due to multiple drilling in one place, resulting in the problem of scrapping;


2. Graphic layer abuse


The specific manifestations are as follows: Some useless connections are made on some graphics layers. It was originally a four-layer board, but more than five layers of circuits were designed, which led to misunderstanding; it violated the conventional design, such as the design of the component surface on the Bottom layer, and the design of the soldering surface on the bottom layer. Top, causing inconvenience, thus maintaining the integrity and clarity of the graphic layer while designing;


3. Characters are randomly placed


This situation is specifically manifested as: the characters cover the SMD pads of the pcb circuit board, which brings inconvenience to the on-off test of the pcb circuit board and the welding of components; and the character design is too small, which will cause difficulties in silk printing the pcb board; The large assembly causes the characters to overlap each other, making it difficult to distinguish clearly;


4. Single-sided pcb circuit board pad aperture setting problem


The pads of single-sided PCB circuit boards are generally not drilled. If the drilling needs to be marked, the hole diameter should be designed as zero. If the value is designed, when the drilling data is generated, the coordinates of the hole appear at this position, and the problem arises;


5. Draw the pcb circuit board pads with filler blocks


It can pass DRC detection when designing pcb circuits, but it is not suitable for PCBA processing. When applying solder resist on the pcb board, the area of the filler block will be completely covered by the solder resist, making it difficult to solder the device;


6. The pcb circuit board design has too many filling blocks or the filling blocks are filled with very thin lines.


Too many filling blocks can easily lead to: loss of light-drawing data, incomplete light-drawing data, or a considerable amount of light-drawing data, which increases the difficulty of data processing;


7. The pad design of pcb circuit board is too short


This situation applies to switch tests. For surface mount devices with too dense pads on the pcb circuit board, the distance between the two pins is relatively small, and the pads on the pcb circuit board are also relatively thin. When installing the test pins, they must be staggered up and down (left and right). If the design of the pcb pad is too short, although it does not affect the device installation, it will make the position of the test pin wrong;


8. Large area grid spacing is too small


The large-area grid spacing is too small (less than 0.3mm). During the manufacturing process of the pcb circuit board, a large number of broken films are likely to be generated during the image transfer process and attached to the pcb board. After the development is completed, it will lead to disconnection;


9. The large-area copper foil of the pcb circuit board is too close to the outer frame


The large-area copper foil of the pcb board should be at least 0.2mm away from the outer frame, otherwise it is easy to cause the copper foil to warp and the resulting solder mask to fall off;


10. The special-shaped hole of the pcb circuit board is too short


The length/width of the special-shaped hole on the PCB board should be ≥ 2:1, and the width should be <1.0mm; otherwise, the drilling machine will easily break the drill when processing the special-shaped hole on the PCB board, which will make PCBA processing difficult and the cost will increase accordingly.


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