PCBA Tech - SMT assembly quality measurement and control technology

1. Automation development trend

SMT products are often micro-small products. The assembly and manufacturing process of SMT products is a micro-manufacturing, precision manufacturing, and high-speed manufacturing process, and has a fairly high degree of automation and production efficiency. Correspondingly, there are very high requirements for the measurement and control technology and methods of the assembly manufacturing process. Quality measurement and control techniques and methods such as manual visual inspection used in the production process of traditional circuit products or manual auxiliary inspection and analysis with the help of conventional inspection equipment can no longer adapt to this production method in terms of accuracy and speed. It is the current development status and an inevitable trend to fully adopt automatic detection methods such as optical automatic detection, as well as the use of computer-aided assembly quality statistics, analysis and control techniques and methods to automatically detect and control SMT assembly quality.

2. Intelligent development trend

The miniaturization, high density, variety of SMT products, as well as the high automation and rapidity of the assembly and manufacturing process, make the quality inspection and control information large and complex, relying on the manual or manual auxiliary quality of the traditional circuit product production process The methods of information collection, statistics, analysis, and diagnosis for quality control are already impossible in terms of speed and accuracy. To this end, based on automated testing technology, with the aid of computer-assisted and intelligent control technology, instead of manual quality information automatic collection, statistics, analysis, diagnosis and feedback of intelligent quality measurement and control technology, it has become the development of SMT assembly quality testing and control technology. The inevitable. The methods and means of intelligent control are becoming more and more abundant

3. Real-time development trend

The high cost of SMT products and their assembly manufacturing, difficulty in repairing and other characteristics, force people to do everything possible to solve quality problems in the assembly production process, so as to avoid product repair and scrap, which puts forward real-time SMT product quality inspection and control. Sexual requirements. The diversity of SMT products and the high-speed assembly and manufacturing process have brought considerable difficulties to this real-time realization. At present, there are many methods for real-time inspection. For example, the inspection system of key assembly equipment configuration can detect and deal with some quality problems in this process in real time. The development trend in this regard is the continuous progress of real-time inspection and control technology at the equipment process level, and the formation and gradual maturity of the real-time inspection and control system for assembly quality at the SMT production system level.

4. Forward development trend

The so-called forward development trend means that the focus of quality inspection and control has shifted from traditional product terminals to various processes in the assembly process. The main starting point is to solve quality problems as much as possible in this process, so as to reduce the processing cost and accumulated risk of quality problems, and then pursue a high pass rate of one-time assembly (zero failure, zero defect or zero repair). Schematic diagram of permanent process inspection points and quality inspection feedback control in the assembly process of SMT products. The self-inspection feedback of the equipment shown in the figure can generally be completed in real time by the built-in inspection function of the assembly equipment. For example, the placement machine can automatically identify the correctness of the components and their pins. Manual participation, shutdown adjustment. As mentioned earlier, with the advancement of detection means and control technology, as well as the application of computer integration technology in SMT production systems, SMT assembly production systems that can perform assembly quality inspection and local or global feedback processing in real time and automatically have also begun. Appear.

5. Diversity development trend

The diversity here refers to the diversity of SMT product assembly process and assembly quality inspection principles and methods. Due to the wide variety of SMT components, different structures and pin types, small and dense solder joints, and complex influencing factors on the quality of the assembly process, it is necessary to use one or two detection principles and methods to accurately inspect and reveal so many types of complex The quality problem is obviously difficult. For this reason, in view of different inspection objects, assembly processes and specific types of quality problems, the current detection principles and methods used have the characteristics of diversity. For example, from the detection principle, there are different types of detection equipment using optics, infrared, ultrasound, X-ray, etc., and from the detection method, there are different forms of testing methods such as contact and non-contact, static and dynamic, semi-automatic and fully automatic, etc. In terms of detection nature, there are online performance testing and functional testing.

Its technological development trend is to use advanced equipment such as automatic optical inspection equipment and X-ray inspection equipment for testing, use high-resolution circuit board optical images and true three-dimensional X-ray image generation technology, innovative image processing algorithms and image enhancement and pattern recognition Combining technology with expert systems and other technologies for quality information processing, and combining functional testing technology based on boundary scan technology, standard instrument modules and virtual instrument software technology with other testing technologies to replace online testing technology or make up for its shortcomings. Its technical development goal is to cope with the test difficulties caused by the miniaturization of surface mount devices, high-density SMA assembly, and BGA-type invisible solder joints.

Because SMT and its component technology are still under continuous development and progress, the corresponding SMT product assembly process and the diverse development trend of assembly quality inspection principles and methods will continue, and new inspection methods and methods will continue. Will keep appearing.

6. Integrated development trend

The SMT product assembly system is an integrated manufacturing system. The SMT product assembly manufacturing process is a comprehensive system engineering. The inspection and control of assembly quality are closely related to the design, supply and marketing, management and other links in the system, and cannot be done in isolation. At present, people have paid more and more attention to this close relationship, and improved product quality inspection and control to the height of the product quality assurance system to be highly integrated with the SMT product assembly system, and planned and coordinated from the height of system engineering. Coordinating and coordinating the quality of raw materials, the performance of assembly equipment, the reliability design for product quality, and the establishment of a quality assurance system and system have greatly improved the controllability of SMT product quality. At the same time, this scientific concept of quality control also solves many quality problems in the bud or eliminates them in prevention. For this reason, this integrated development trend is also the inevitable development of SMT and its measurement and control technology.