Discussion on the Deficiencies of PCB Design Explained by PCB Factory

Discussion on the Deficiencies of PCB Design Explained by PCB Factory

1、 Unclear definition of processing level

1. The single panel is designed on the TOP layer. If no instructions are given, it may be difficult to weld the fabricated boards with devices.

2. For example, when designing a four layer board, the TOP mid1 and mid2 bottom layers are used, but they are not placed in this order during processing, which requires explanation.

2、 Graphic layer abuse

1. Some useless connections have been made on some graphic layers, but the original four layer board has been designed with more than five layers of circuits, causing misunderstanding.

2. It is easy to design the diagram. Take Protel software as an example, use the Board layer to draw lines for each layer, and use the Board layer to draw marking lines. In this way, when photo drawing data, because the Board layer is not selected, the connection is missed and the circuit is broken, or because the Board layer marking line is selected, the circuit is short circuited. Therefore, the graphic layer is kept complete and clear during design.

3. It violates the conventional design, for example, the component surface is designed at the Bottom layer, and the welding surface is designed at the Top, causing inconvenience.

3、 Pads overlap

1. Overlapping of pads (except surface mount pads) means overlapping of holes. In the drilling process, the drill bit will be broken due to multiple drilling at one place, resulting in hole damage.

2. Two holes in the multilayer board are overlapped. For example, one hole is the isolation plate, and the other hole is the connection plate (rosette pad). In this way, the negative film is drawn as the isolation plate, resulting in scrapping.

4、 Draw pads with filler blocks

The pad drawn with filler block can pass DRC inspection when designing the circuit, but it cannot be processed. Therefore, such pads cannot directly generate solder resistance data. When solder resistance is applied, the filler block area will be covered by solder resistance, which leads to difficulty in device welding.

5、 Single side pad aperture setting

1. Single side pads generally do not drill holes. If the holes need to be marked, the hole diameter should be designed as zero. If the numerical value is designed, the hole coordinates will appear at this position when the drilling data is generated, which will cause problems.

2. Single side pads such as drilling holes shall be specially marked.

6、 The electrical layer is both a mosaic pad and a connection

Because the power supply is designed as a rosette pad, the image on the stratum is opposite to that on the actual PCB, and all connecting lines are isolation lines, which should be very clear to the designer. By the way, when drawing several groups of power supply or several types of ground isolation lines, be careful not to leave a gap to short circuit the two groups of power supply, or block the connection area (to separate a group of power supply).

7、 Character misplacement

1. The SMD pad of the character cover pad brings inconvenience to the on-off test of the printed circuit board and component welding.

2. The character design is too small, which makes screen printing difficult, and too large makes characters overlap and difficult to distinguish. Circuit board assembly, circuit board design, and circuit board processing manufacturers explain the deficiencies in PCB design explained by circuit board manufacturers.