Top 10 Common Problems In PCB Design

1. Character cover welding plate SMD welding plate, which brings inconvenience to the on-off test of printed board and welding of components.

2, the character design is too small, resulting in screen printing difficulties, too large character overlap, difficult to distinguish.

Second, the graphic layer of abuse

1. Made some useless connections on some graphic layers. Designed circuits with more than five layers instead of four layers, which caused misunderstanding.

2. It is easy to design diagrams. Take Protel software as an example to draw lines at each layer and mark lines at each layer.

3. Violation of routine design, such as component surface design at Bottom layer and welding surface design at Top, causing inconvenience.

Iii. Overlap of welding plates

1. The overlap of welding disk (except surface bonding disk) means the overlap of holes. In the drilling process, the drill bit will be broken due to repeated drilling in one place, leading to the damage of holes.

2. The two holes in the multilayer plate overlap, such as one hole is the isolation plate and the other hole is the connection plate (flaps), which is shown as the isolation plate after the negative is drawn, resulting in the scrap.

Iv. Setting the aperture of the single-side welding plate

1. Single welded plate generally does not bore holes. If drilling is to be marked, its aperture should be designed to be zero.If the numerical value is designed, then the coordinates of the hole will appear at this position when the borehole data is generated, and the problem will arise.

2. Single-side welding plate should be specially marked if drilling hole.

Five, the electric formation is flower welding plate and connection

Because of the power source designed as a splash-pad, the formation is the opposite of the image on the actual printed board, and all connections are isolation lines, which the designer should be very clear about.Here, by the way, care should be taken to draw the lines of several sets of power sources or of several kinds of ground so as not to leave gaps, short-circuit the two sets of power sources, or create an area blockade of the connection (so that one set of power sources is separated).

Draw a pad with a filler block

The filling block drawing pad can pass DRC inspection when designing the circuit, but it is not suitable for processing. Therefore, the type of pad cannot directly generate welding resistance data. When the welding flux is applied, the filling block area will be covered by the welding flux, resulting in the welding difficulty of the device.

Seven, the definition of processing level is not clear

1. The single panel is designed on the TOP layer. If the positive and negative parts are not explained, the panel may be equipped with devices and not easy to be welded.

2. For example, TOP MID1 and MID2 Bottom four layers are used in the design of a four-layer plate, but the processing is not placed in such order, which requires explanation.

Too many filling blocks in the design or filling blocks with very thin lines

1. There is a phenomenon of loss of light-painted data, and the light-painted data is incomplete.

2. As the filling blocks are drawn line by line in light drawing data processing, the amount of light drawing data generated is quite large, which increases the difficulty of data processing.

9. Surface mount device bonding pad is too short

This is for on-off testing. For surface mount devices that are too dense, the space between the two legs is relatively small, and the solder plate is also relatively thin. The installation of test needles must be in a cross position (left and right).

The spacing of large area grids is too small

The edge between the grid lines in a large area is too small (less than 0.3mm). In the manufacturing process of printed board, many film fragments are likely to be attached to the board after the rendering process, resulting in broken lines.