1、 Character shuffling

1. The SMD solder pad of the character cover brings inconvenience to the on/off testing of printed boards and the welding of components.

2. The character design is too small, making it difficult for screen printing, and it can cause characters to overlap and be difficult to distinguish.

 

2、 Abuse of graphic layers

1. Some useless connections were made on some graphics layers, but the original four layer board was designed with circuits above five layers, which caused misunderstandings.

2. When designing, it is easy to draw. Using Protel software as an example, use the Board layer to draw lines that are common to each layer, and then use the Board layer to draw annotation lines. This way, when conducting photo data, if the Board layer is not selected, the lines may be missed and the circuit may be broken, or if the annotation lines of the Board layer are selected, the integrity and clarity of the graphics layer will be maintained during design.

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

 

3、 Overlap of pads

1. The overlap of solder pads (except for surface mounted solder pads) means the overlap of holes. During the drilling process, the drill bit may break due to multiple drilling at one location, resulting in damage to the holes.

2. In a multi-layer board, two holes overlap, such as one hole being an isolation plate and the other hole being a connecting plate (patterned solder plate). This results in the appearance of an isolation plate after drawing the film, resulting in scrapping.

 

4、 Setting of single sided pad aperture

1. Single sided pads generally do not require drilling, and if drilling is required, the hole diameter should be designed to be zero. If numerical values are designed, the coordinates of the holes will appear at this location when generating drilling data, leading to problems.

2. Single sided pads, such as drilling holes, should be specially marked.

 

5、 Draw solder pads with filler blocks

Drawing solder pads with filler blocks can pass DRC inspection during PCB circuit design, but it is not feasible for processing. Therefore, solder pads cannot directly generate solder mask data. When solder mask is applied, the filler block area will be covered by solder mask, causing difficulty in device soldering.

 

6、 The electrical layer is both a solder pad and a connecting wire

Because the power supply designed as a patterned pad method has the opposite image between the ground and the actual printed circuit board, all wiring is isolated, which should be very clear to the designer. By the way, when drawing several sets of power supplies or isolation lines for several types of land, care should be taken not to leave any gaps, causing a short circuit between the two sets of power supplies, or blocking the connection area (causing one set of power supplies to be separated).

 

7、 Unclear definition of processing level

1. The single panel design is on the TOP layer, and if it is not specified, the resulting board may not be easy to solder due to the installation of components.

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

 

8、 There are too many filling blocks in PCB design or the filling blocks are filled with extremely thin lines

1. There is a phenomenon of loss of photo data and incomplete photo data.

2. Due to the use of lines to draw fill blocks in photo data processing, the amount of photo data generated is quite large, increasing the difficulty of data processing.

 

9、 Surface mount device solder pad too short

This is for on/off testing. For surface mount devices that are too dense, the distance between their two legs is relatively small, and the solder pads are also quite thin. When installing test pins, they must be staggered up and down (left and right). If the solder pads are designed too short, although it does not affect device installation, it will cause the test pins to be misaligned.

 

10、 The spacing between large area grids is too small

The edges between the large area grid lines are too small (less than 0.3mm), and during the manufacturing process of printed boards, the image conversion process can easily produce many broken films that adhere to the board after the image is displayed, resulting in wire breakage.

 

11、 The distance between the large area copper foil and the outer frame is too close

A distance of at least 0.2mm should be ensured between the large area copper foil and the outer frame, as milling onto the copper foil during contour milling can easily cause the copper foil to warp and cause the solder resist to fall off.

 

12、 Abnormal hole too short

The length/width of the irregular hole should be ≥ 2:1, and the width should be>1.0mm. Otherwise, the drilling machine is prone to breakage when processing the irregular hole, causing difficulties in processing and increasing costs.

 

13、 Uneven graphic design

During graphic electroplating, uneven coating is caused, which affects the quality.

 

14、 Unclear design of exterior borders

Some customers have designed contour lines for Keep layer, Board layer, Top over layer, etc., and these contour lines do not overlap, making it difficult for PCB manufacturers to determine which contour line to use.