In PCB design, electronic engineers need to pay attention to many aspects. Novice engineers often ignore Mark points, but senior engineers love and hate Mark points, and even have to spend time on Mark points. Why is Mark point so important? How to design Mark points?
1. What is the Mark point?
Mark points, also known as positioning points or positioning marks, are special marking points added to the circuit board after the PCB design is completed. They are usually located in the corners or important positions of the circuit board, and have clear coordinate positions. The main function of the Mark point is to provide a positioning reference for calibrating and aligning the position and orientation of the PCB in the subsequent manufacturing and assembly process.
Mark points on the PCB are generally as follows:
2. What are the classifications and functions of Mark points?
Mark points can be divided into global Mark points and local Mark points according to IPC-SM-782A classification. Global Mark points can be divided into single-board Mark points and panel Mark points. Single-board Mark points are used to locate all circuits on a single board The position of the feature; the jigsaw Mark point is used to assist in positioning the position of all circuit features on the jigsaw board; the local Mark point is the reference point mark for locating a single component, so as to improve the mounting accuracy (mainly for QFP, BGA and other pins Many and dense important devices).
The global Mark points, local Mark points and jigsaw Mark points are as follows:
3. Why should mark points be placed after PCB design?
①The accuracy of the manufacturing process
Placing Mark points can help manufacturers accurately position circuit boards in PCB manufacturing. Manufacturing equipment can use Mark points as a reference to ensure that components and circuit boards are aligned during cutting, drilling, patching, and soldering, thereby improving manufacturing efficiency. accuracy.
② Circuit board assembly accuracy
In PCB assembly, Mark points can help automation equipment to accurately locate the case. Equipment such as placement machines, welding machines, and testing equipment can use Mark points as a reference to ensure accurate placement and connection of components, thereby improving assembly accuracy and reliability. sex.
③Troubleshooting and maintenance
When the circuit board fails or needs to be repaired, the Mark point can be used as a positioning reference point. The technician can use the Mark point to determine the fault location and follow the signal path for repair operations, thereby improving troubleshooting and repair efficiency.
In general, placing mark points is an important step after the PCB design is completed, and it plays a key role in the manufacturing preparation and assembly process. By providing a positioning reference, the mark point can improve the accuracy of manufacturing and assembly, and also facilitate troubleshooting and maintenance work. Designers should distribute mark points reasonably to ensure that they are clearly visible, coordinate accurately, and communicate effectively with manufacturers. Placing mark points is an important measure to ensure the quality and accuracy of PCB.
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