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14 major problems in PCB design
- May 16, 2017 -

1. Overlap of solder Plates
1, the solder disc (except the surface of the solder plate) overlap, means that the hole overlap, in the drilling process will be because of a number of holes in a drill caused by a broken drill bit, resulting in holes damage.
2, multi-layer board two holes overlap, such as a hole position for the isolation disc, the other hole for the connection disc (flower pad), so painted the film after the performance of the isolation disc, resulting in scrap.

2. Misuse of the graphics layer
1, in some graphics layer to do some useless wiring, originally is four-storey board has designed more than five layers of lines, causing misunderstandings.
2, design time diagram saves, to Protel Software as an example to each layer of the line with the Board layer to draw, the Board layer is also used to delimit the marking line, so that when the data is painted, because the Board layer is not selected, the line is missed out, or because the selection of Board layer of marking lines and short-circuit, so design to maintain the integrity and clarity of the graphics layer.
3, violates the conventional design, such as component surface design at the Bottom layer, the weld surface design in the top, causes the inconvenience.

3. the character of disorderly place
1, character cap solder disc SMD, to the PCB's breaking test and welding components inconvenience.
2, the character design is too small, resulting in the difficulty of screen printing, too General Assembly to make characters overlap, difficult to distinguish between.

4. Setting of the aperture of single-sided solder disc
1, single-sided solder plate is generally not drilled, if the drilling needs to be marked, its aperture should be designed to zero. If a numeric value is designed so that the borehole data is generated, the location of the hole is marked with a problem.
2, single-sided pad such as drilling should be special marking.

5. Drawing Pad with filler
With the filler block to draw the design of the circuit can pass through the DRC check, but for processing is not possible, so the type solder disc can not directly generate solder data, on the solder block, the filler area will be blocked flux overlay, causing device welding difficult.

6. the electric stratum is also the flower solder disc is the connection
Because the design of the mode of the flower solder disc power, strata and the actual printed board on the contrary image, all the wiring is the isolation line, the designers should be very clear. By the way, it should be careful to draw a few sets of power or a few areas of the isolation line, not leaving the gaps in the two sets of power short-circuit, nor can it cause the connection of the regional blockade (to make a group of power separated).

7. The definition of processing level is unclear.
1, single-sided plate design in the top layer, if not the pros and cons to do, perhaps the board is made up of devices and not welding.
2, for example, a four-storey board design using top mid1, Mid2 bottom four layers, but the processing is not in such order, this requires a description.

8. Too many fill blocks in the design or fill blocks with a very thin line
1, produces the light painted data has the phenomenon of loss, the light painted data is incomplete.
2, because the filler block in the light painted data processing is using line A to draw, resulting in the amount of light painted data is quite large, increase the difficulty of data processing.

9. surface mount device solder disc too short
This is for the breaking test, for too dense surface mount devices, the spacing between the two legs is fairly small, the solder plate is also quite thin, the installation of testing needle, must be up and down (left and right) staggered position, such as the design of the disc too short, although not affect the device installation, but will make the test needle not open.

10, large area grid spacing is too small
Forming large area mesh line between the edge of the same line is too small (less than 0.3mm), in the manufacturing process of printed board, the graph transfer process after the obvious after the shadow prone to many pieces of the membrane adhesion on the board, resulting in disconnection.

11, large area copper foil distance from the outer frame too close
Large area of copper foil to the outside box should be at least 0.2mm to ensure that the spacing, because in the milling profile, such as milling to copper foil easy to cause the rise of the copper foil and caused by the resistance flux shedding problems.

12, outline border design unclear
Some customers in Keep layer, Board layer, top over layer and so on all design contour lines and these contour lines do not coincide, resulting in PCB manufacturers are difficult to determine which line of shape to prevail.

13. Uneven Graphic Design
In the graphics plating, the coating caused uneven, affecting quality.

14, special hole too short
Special-shaped hole length/width should ≥ 2:1, width should be >1.0mm, otherwise, drilling machine in the processing of special holes in the very easy to break drilling, resulting in processing difficulties, increase costs. 2