1.The bonding pad overlap:
The overlap of the pads (except for the surface mount pads) means the overlap of the holes. In the drilling process, the drill bit is broken due to multiple holes in one hole, resulting in damage to the holes.
The two holes in the multilayer PCB board overlap, for example, one hole is the isolation plate, and the other hole is the connection plate (thermal pad), so that the negative film is formed as a spacer disk, resulting in scrapping.
2.The graphics layer abuse:
Some useless connections were made on some graphics layers. Originally, the four-layer pcb board was designed with five or more layers, which caused misunderstanding.
To save trouble, when designing , take Protel software as an example, the layers of each layer are drawn with the board layer, and the board layer is used to draw the line, so when the light drawing data is selected, because the board layer is not selected, it is missed. Wired and disconnected, or short-circuited by selecting the marking line of the Board layer, so the design layer is kept intact and clear.
Violation of the conventional design, such as the design of the component surface in the Bottom layer, the welding surface design in the Top, causing inconvenience.
3.The characters are placed:
The character cover pad SMD soldering piece brings inconvenience to the on-off test of the printed board and the soldering of components.
The character design is too small, causing the difficulty of screen printing, too large will make the characters overlap each other, difficult to distinguish.
4. Draw pads with padding
Draw a pad with a pad to pass the DRC check when designing the line, but it is not suitable for processing. Therefore, the pad cannot directly generate solder resist data. When the solder resist is applied, the pad area will be covered by the solder resist, resulting in the device is difficult to solder.
5. The electric ground layer is a thermal pad and a connection
Designed as a thermal -padded power supply, the ground plane is the opposite of the actual printed board image, and all connections are isolated lines, which should be very clear to the designer. By the way, when drawing several sets of power supply or isolation lines of several grounds, be careful not to leave a gap, so that the two sets of power supplies are short-circuited, and the area of the connection cannot be blocked (so that a group of power supplies are separated).
The difference between PCB and PCBA
What is a PCB? How did PCBA evolve? What is the difference between PCB and PCBA? Let's take a closer look below.
PCB is the abbreviation of Printed Circuit Board. Because it is made by electronic printing, it is called "printing" circuit board. PCB is an impor...