Ten defects of PCB board design process
First, the definition of processing level is not clear
Single-panel design in the TOP layer, if not stated positively and negatively, it may be made out of the board to install the device without good welding.
Second, the large area copper foil is too close to the frame
The large area copper foil should be at least 0.2mm above the distance from the outer frame. This may cause the copper foil to warp and cause the solder resist to fall off when it is milled onto the copper foil.
Third, draw pad with pad
Drawing pad pads with fillers can be checked by DRC when designing the circuit, but it is not possible to process, so the pad can not directly generate the solder mask data. In the case of solder resist, the pad area will be covered by the solder mask, resulting in devices. Welded equipment is difficult.
Fourth, the electrical ground is a flower pad and is connected
Because it is designed as a flower pad power source, the ground layer is the opposite of the actual printed board image. All the connection lines are isolated lines. Care should be taken when drawing several groups of power supplies or several isolation lines, and no gaps can be left. Short circuit of the power supply also does not block the connection area.
Five, the characters indiscriminately
The character covers the pad SMD soldering pads, causing inconvenience to the printed circuit board continuity test and component soldering. The character design is too small, causing difficulties in screen printing. Too large characters cause characters to overlap and are difficult to distinguish.
Sixth, surface mount device pads are too short
This is for the continuity test, for too dense surface mount devices, the spacing between the two feet is quite small, the pads are also very thin, the mounting test pin must be staggered position up and down, such as the pad design is too short, although not Affects device installation but leaves the test pin out of place.
Seven, single-sided pad aperture settings
Single-sided pads are generally not drilled. If the drill hole needs to be marked, its aperture should be designed to be zero. If a numerical value is designed, a hole coordinate appears at this position when drilling data is generated, and a problem arises. Single-sided pads such as drill holes should be marked.
Eight pad overlap
In the drilling process, the drill bit breaks due to multiple drillings at one site, resulting in hole damage. The two holes in the multi-layer board overlap, and the isolation film is represented after the film is drawn, resulting in scrap.
Nine, too many filling blocks in the design or filling blocks filled with very thin lines
There is a loss of light drawing data, and the light drawing data is incomplete. Because the filling blocks are drawn with lines one by one during the processing of the light drawing data, the amount of light drawing data is quite large, which increases the difficulty of data processing.
X. Graphic Layer Misuse
Some useless lines have been made on some graphic layers. Originally four-layer boards were designed with more than five layers of lines, causing misunderstandings. Violation of conventional design. The design should maintain the integrity and clarity of the graphics layer.
Single-panel design in the TOP layer, if not stated positively and negatively, it may be made out of the board to install the device without good welding.
Second, the large area copper foil is too close to the frame
The large area copper foil should be at least 0.2mm above the distance from the outer frame. This may cause the copper foil to warp and cause the solder resist to fall off when it is milled onto the copper foil.
Third, draw pad with pad
Drawing pad pads with fillers can be checked by DRC when designing the circuit, but it is not possible to process, so the pad can not directly generate the solder mask data. In the case of solder resist, the pad area will be covered by the solder mask, resulting in devices. Welded equipment is difficult.
Fourth, the electrical ground is a flower pad and is connected
Because it is designed as a flower pad power source, the ground layer is the opposite of the actual printed board image. All the connection lines are isolated lines. Care should be taken when drawing several groups of power supplies or several isolation lines, and no gaps can be left. Short circuit of the power supply also does not block the connection area.
Five, the characters indiscriminately
The character covers the pad SMD soldering pads, causing inconvenience to the printed circuit board continuity test and component soldering. The character design is too small, causing difficulties in screen printing. Too large characters cause characters to overlap and are difficult to distinguish.
Sixth, surface mount device pads are too short
This is for the continuity test, for too dense surface mount devices, the spacing between the two feet is quite small, the pads are also very thin, the mounting test pin must be staggered position up and down, such as the pad design is too short, although not Affects device installation but leaves the test pin out of place.
Seven, single-sided pad aperture settings
Single-sided pads are generally not drilled. If the drill hole needs to be marked, its aperture should be designed to be zero. If a numerical value is designed, a hole coordinate appears at this position when drilling data is generated, and a problem arises. Single-sided pads such as drill holes should be marked.
Eight pad overlap
In the drilling process, the drill bit breaks due to multiple drillings at one site, resulting in hole damage. The two holes in the multi-layer board overlap, and the isolation film is represented after the film is drawn, resulting in scrap.
Nine, too many filling blocks in the design or filling blocks filled with very thin lines
There is a loss of light drawing data, and the light drawing data is incomplete. Because the filling blocks are drawn with lines one by one during the processing of the light drawing data, the amount of light drawing data is quite large, which increases the difficulty of data processing.
X. Graphic Layer Misuse
Some useless lines have been made on some graphic layers. Originally four-layer boards were designed with more than five layers of lines, causing misunderstandings. Violation of conventional design. The design should maintain the integrity and clarity of the graphics layer.