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How many common standards do you know about printed circuit boards
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Several common standards for printed circuit boards

1) IPC-ESD-2020: Joint standard for the development of electrostatic discharge control procedures. Including the necessary design, establishment, implementation and maintenance of electrostatic discharge control procedures. According to the historical experience of certain military organizations and commercial organizations, it provides guidance for handling and protecting electrostatic discharge sensitive periods.

2) IPC-SA-61 A: Semi-aqueous cleaning manual after welding. Including all aspects of semi-aqueous cleaning, including chemical, production residues, equipment, technology, process control, and environmental and safety considerations.

3) IPC-AC-62A: Water cleaning manual after welding. Describe the cost of manufacturing residues, types and properties of aqueous cleaning agents, aqueous cleaning processes, equipment and techniques, quality control, environmental control, and employee safety, and cleanliness measurement and measurement.

4) IPC-DRM -4 0E: Desktop reference manual for through-hole solder joint evaluation. Detailed description of components, hole walls and welding surface coverage according to standard requirements, in addition to computer-generated 3D graphics. Covers tin filling, contact angle, tin dip, vertical filling, solder pad coverage, and numerous solder joint defects.

5) IPC-TA-722: Welding Technology Evaluation Manual. Includes 45 articles on all aspects of soldering technology, covering general soldering, soldering materials, manual soldering, batch soldering, wave soldering, reflow soldering, vapor phase soldering and infrared soldering

 一、Automatic X-ray inspection

Using the difference in the absorption rate of different substances to X-rays, fluoroscopy the parts that need to be tested and find defects. It is mainly used to detect defects in ultra-fine pitch and ultra-high-density circuit boards, as well as bridging, missing chips, poor alignment and other defects generated during the assembly process. It can also use its tomographic imaging technology to detect internal defects in IC chips. It is the only way to test the soldering quality of the ball grid array and the blocked solder balls. The main advantage is the ability to detect BGA welding quality and embedded components, without fixture cost; the main disadvantages are slow speed, high failure rate, difficulty in detecting reworked solder joints, high cost, and long program development time. This is a relatively new test. The method remains to be further studied.

二、 Laser detection system

It is the latest development of PCB testing technology. It scans the printed board with a laser beam, collects all measurement data, and compares the actual measurement value with the preset qualified limit value. This technology has been proven on the bare board and is being considered for assembly board testing. The speed is sufficient for mass production lines. Fast output, no fixtures and visual non-covered access are its main advantages; high initial cost, maintenance and use problems are its main disadvantages.

三. Size detection

Use the two-dimensional image measuring instrument to measure the hole position, length and width, position and other dimensions. Since PCB is a small, thin and soft type of product, contact measurement can easily deform and cause inaccurate measurement. The two-dimensional image measuring instrument has become the best high-precision size measuring instrument. After being programmed, the image measuring instrument of Sirui Measurement can realize fully automatic measurement, which not only has high measurement accuracy, but also greatly shortens measurement time and improves measurement efficiency.