In addition to knowing the layout and routing rules during the PCB design process, you also need to pay attention to some batch processing issues after the PCB design is completed, such as the design of process edges, Make points and positioning holes. They play a vital role in the actual production and assembly process and can significantly improve production efficiency, product quality and reliability.

Ⅰ. The role of process edges

    The process edge is also called the transfer edge. It is the position reserved for mounting the guide rail when the PCB board is mounted on SMT. Because this edge needs to be stuck in the guide rail groove, there are some requirements for the width, and the above No components can be placed, usually just add them on both sides! Coupled with the process edge, production efficiency and quality control can be greatly improved. PCB manufacturing usually uses highly automated production lines, including drilling, copper plating, patching and other processes. The process edge also provides additional space for automated equipment, allowing it to smoothly grab, move and fix PCB boards, and also reduces the probability of edge wear or damage during subsequent transportation and reprocessing. The existence of process edges can protect the core area of ​​the PCB from damage and reduce the scrap rate caused by physical damage.

Ⅱ. The role of Mark points

  1. Make is also called optical positioning point. When SMT is mounted, the mounter can find the Make point for position calibration through operation. Make points are generally divided into 3 categories: single board Make, process edge Make and local special positioning Make. The area near the Make point should be empty and there should be no silk screen or other elements to avoid unrecognizable. The general size design requires a minimum diameter of 1mm and a maximum of 3mm.
  2. Support AOI inspection: The automatic optical inspection (AOI) system also relies on Mark points for efficient and accurate quality control. AOI will scan the entire circuit board and compare the actual installation status against the predefined standard mode;
  3. As the design of electronic products becomes more and more complex, more and more products are beginning to adopt double-sided or even multi-layer board structures. In this case, it is particularly important to correctly layout the relative relationship between the upper and lower surfaces and even the internal layers. Ensure consistency and coordination between all levels.

Ⅲ. The role of positioning holes

     Also called physical fixing holes, they are mainly used to physically position the PCB during assembly and testing. Generally, these holes are located at the four corners or edges of the PCB and are used in conjunction with fixtures or positioning pins on production equipment. The fixing holes can ensure the precise positioning of the PCB during processing, thereby improving the accuracy of assembly and testing. During multiple processing or testing processes, positioning holes can ensure the consistency and repeatability of each operation.

  1. Comprehensive considerations and best practices
  2. When designing a PCB, the layout of process edges, mark points, and locating holes should be comprehensively considered to ensure that they can work together to improve processing accuracy and efficiency. For different types of PCBs, the number and location of these elements can be flexibly selected according to their specific applications and production requirements. In the actual production process, we place the make points and locating holes on the process edges.
  3. Balance costs and benefits: Although adding process edges, mark points and positioning holes will slightly increase the cost of PCB, in the long run, the economic benefits brought by increased production efficiency, improved quality and reduced scrap rate far outweigh the initial investment.