What are the methods for PCB board dissection?

PCB board dissection is crucial aspect of PCB design.However,because it involves sanding(a hazardous task）and tracing (a simple,repetitive task),many designers are reluctant to undertake this task.Many even believe that PCB board dissection is not a technical task,something that junior designers can handle with minimal training.This perception is somewhat common,but as with many tasks,there are certain techniques for dissecting PCBs.Mastering these techniques can save designers significant time and labor.Let’s discuss this in detail.

1.The Concept of PCB Dissection

PCB dissection refers to the process of obtaining schematics and board layouts(PCB drawings)from a physical PCB.This process is used for subsequent development.including component installation,in-depth testing,and circuit modification.Since this process falls outside the scope of pcb dissection but is related to it,it will only be briefly introduced and not discussed in detail.

2.The PCB dissection Process

• Remove components from the original board.
• Scan the original board to obtain a graphic file.
• Grind away the surface layer to obtain the intermediate layer
• Scan the intermediate layer to obtain a graphic file.
• Repeat steps 2-4 until all layers are processed.
• Use specialized software to convert the graphic file into an electrical file-the PCB diagram.If suitable software is available,the designer only needs to trace the diagram once.
• Check and verify to complete the design.

3.PCB Profiling Techniques

PCB profiling,especially multi-layer PCBs,is a time-consuming and laborious task involving a significant amount of repetitive work.Designers must be patient and meticulous,otherwise errors are easily made.The key to successful PCB profiling lies in using appropriate software to replace manual repetitive tasks,saving time and ensuring accuracy.

(1)Always use a scanner during profiling.

Many designers are accustomed to drawing lines directly on PCB design software such as proTel,padsor,or CAD.This is a very bad habit.The scanned graphic file serves as both the basis for converting to the PCB file and as a reference for subsequent verification.Using a scanner can significantly reduce the difficulty and intensity of labor.It’s no exaggeration to say that if a scanner is fully utilized,even someone without design experience can complete PCB profiling.

(2)Single-Direction Grinding.

Some designers, driven by speed, opt for bidirectional grinding (i.e., grinding away layers from the front and back surfaces toward the middle). This is a serious mistake. Bidirectional grinding can easily wear through, damaging other layers, with predictable consequences. Due to the manufacturing process and the presence of copper foil and pads, the outer layers of a PCB are the hardest, while the middle layers are the softest. Therefore, problems are most severe in the middle layers, often making them impossible to grind. Furthermore, PCB materials, hardness, and elasticity vary from manufacturer to manufacturer, making accurate grinding difficult.

(3)Choose excellent conversion software.

Converting scanned graphics files to PCB files is crucial. With a good conversion file, designers can simply trace the graphics and complete the work. EDA2000 is highly recommended; it’s very convenient.

The above are my personal thoughts, which I put forward for discussion, hoping to stimulate further discussion.