1. The overlap of PCB pads

1. The overlap of the pads (except for the surface mount pads) refers to the overlap of the holes. During the drilling process, a drill bit may break from excessive drilling in one area, leading to damage to the holes.

2. When two holes in a multilayer board overlap—such as one being an isolation pad and the other a connection pad (flower pad)—the film may incorrectly represent the isolation pad after drawing, resulting in scrap.

2. The misuse of the graphics layer

1. Some unnecessary connections are made on various graphics layers. Originally intended as a four-layer board, the design may end up with over five layers of circuits, leading to misunderstandings.

2. To simplify the design process, some designers, using Protel software as an example, draw connections on each layer while utilizing the Board layer for marking. This can lead to issues during light drawing data, where the Board layer is not selected and thus omitted. Consequently, connections may be broken, or short circuits may occur due to the selection of the marking line on the Board layer. It is essential to maintain the integrity and clarity of the graphics layer during design.