Analyze the future development direction of precision testing technology

   The development of advanced technology is changing with each passing day, and precision testing technology should adapt to this development. The role of precision testing technology in the mechanical discipline is to serve the advanced manufacturing industry and assume the responsibility of quality technology assurance. This requires that the quality of products must first be improved. The starting point, this is also the most important goal to be achieved.

    Secondly, precision testing technology should improve the production efficiency of products. Therefore, the detection method must be able to adapt to the requirements of rapid development of production, not only for testing, and not to affect the efficiency of production because of the requirements of testing. From a more positive perspective , It should be due to the good service of precision testing technology to promote the improvement of production capacity. According to the requirements of the development of advanced manufacturing technology and the development law of precision testing technology itself, we are constantly expanding new measurement principles and testing methods, and testing information processing technology. As far as the mechanical discipline is concerned, it is expected that the following aspects need to be developed.

    1. Visual testing technology

    There are many non-contact testing technologies, especially the visual testing technology. The development of modern visual theory and technology is not only to simulate the functions that the human eye can complete, but more importantly, it can complete the work that the human eye cannot do. So As the latest technology today, vision technology has been rapidly developed on the basis of the continuous maturity and improvement of electronics, optics, and computers. Vision testing technology is an emerging testing technology based on computer vision research. Vision with computer vision research The content of pattern recognition and visual understanding is different. The visual testing technology focuses on the geometric size of objects and the measurement of the position of objects, such as the measurement of the three-dimensional size of the car body in white, the rapid measurement of the three-dimensional surface shape of molds, and the coaxiality measurement of large workpieces. It can be widely used in active and real-time measurement processes such as online measurement and reverse engineering. Visual testing technology has developed rapidly abroad. As early as the 1980s, the American National Bureau of Standards estimated that 90% of inspection tasks It will be completed by the visual test system. In the 1980s, more than 100 companies in the United States entered the market for visual test systems. It can be seen that the visual test system is indeed very promising. It has been seen abroad at the Beijing International Machine Tool Expo in October 1999. Instruments developed using visual inspection technology, such as mobile optical coordinate measuring machines, high-speed and high-precision digital scanning systems, non-contact optical coordinate measuring machines and other advanced instruments.

    2. Measurement control in zero waste production

    In the manufacturing industry, the ideal goal of quality assurance is to implement zero-waste manufacturing. In the process of achieving this goal, the role and importance of precision testing technology are self-evident. The processing quality of parts and the whole machine Assembly quality is related to processing equipment, testing equipment, and the analysis and processing of test information. Therefore, to achieve zero-waste production, from the perspective of precision testing, the following issues should be considered: (1) Before processing the workpiece, check the machine tool in advance. Quickly and accurately verify the processing equipment to obtain the accuracy of the machine tool, which is very beneficial to greatly reduce and even eliminate rework. Of course, this includes the research and development of testing equipment. (2) Workpieces in the production process For online measurement or 100% inspection of workpieces, it is necessary to study test equipment suitable for dynamic or quasi-dynamic, and even special test equipment that can be integrated into processing equipment, to achieve real-time testing, and continuously modify process parameters based on test results. Supplementary adjustment or feedback control of processing equipment. From the aspect of accuracy theory, it is necessary to study the dynamic accuracy theory, including the evaluation of dynamic accuracy, etc. (3) Study how to make full use of measurement information to achieve zero waste production. Through 100% online measurement data Make full use of the analysis of the dynamic characteristics of the error distribution in the processing and measurement process.At the same time, according to the dynamic characteristics of the processing error and the accuracy loss characteristics of the sensor accuracy, as well as the product quality requirements and tolerance regulations, the basic theoretical model of zero waste manufacturing is given. Make full use of modern mathematical methods such as artificial neural networks and genetic algorithms to accurately predict processing quality and achieve quality control in advance.

    3. Measuring size continues to develop towards two extremes

    The so-called two extremes refer to the large size and small size relative to the current measurement size. Generally, the measurement of size has been widely noticed, and a variety of test methods have been developed. In recent years, due to the rapid development of the national economy and urgent needs , Which makes many aspects of production and engineering test requirements beyond our test range, such as the measurement of aircraft shape, the measurement of key components of large machinery, the alignment measurement of elevator guide rails in high-rise buildings, the on-site calibration of tank trucks, etc. It is required to be able to perform large-scale measurements; the rapid development of microelectronics and biotechnology, the need to explore the microcosm of matter, the continuous improvement of measurement accuracy, and the need for micron and nanometer tests.

    (1) Large-scale measurement methods such as engineering geodetic survey methods refer to the transplantation and improvement of certain principles and methods of geodetic surveying into mechanical engineering surveying, resulting in new measurement methods, and other methods of measuring large dimensions, such as Laser tracking interferometric three-dimensional size measurement system.

    (2) From the perspective of manufacturing trends, nano-testing technology requires that the allowable error be reduced by 1/3 every ten years, so the measurement is required to have higher and higher accuracy and can be traced to international standards (ISO). Of course, nano-measurement is also There are many kinds, including optical interferometer, quantum interferometer, capacitance micrometer, X-ray interferometer, frequency tracking Fabry-Perot etalon, scanning electron microscope (SEM), scanning tunneling microscope (STM), atomic force microscope (AFM) ), molecular measuring machine M3 (molecular measuring machine), etc.

    4. Diversification of measurement methods

    (1) The application of multi-sensor fusion technology in the manufacturing siteMulti-sensor fusion is a method to solve the measurement information acquisition in the measurement process, which can improve the accuracy of the measurement information.

    Since multiple sensors obtain information in different ways or from different angles, the information fusion between them can be used to remove the false and preserve the truth and improve the measurement accuracy.

    (2) Building block and combined measurement methods The three-dimensional size measurement system of the body in white belongs to this type of method.It can also be said that it is a special coordinate measuring machine with good flexibility. The key is to establish the system.

    (3) Portable measuring instruments such as portable optical fiber interferometers, portable large-range three-dimensional measurement systems, etc., are often used to solve large-scale measurement problems on site.

    (4) Virtual instrument Virtual instrument is the application of virtual reality technology in the field of precision testing, and there has been in-depth research in China. One is to virtualize a variety of digital test instruments into a digital intelligent test supported by computer hardware Instruments; the other is to study virtual measurement in virtual manufacturing, such as virtual gauge blocks, virtual coordinate measuring machines, etc.

    (5) Intelligent structure, which belongs to structure detection and fault diagnosis, is an interdisciplinary subject integrating intelligent technology, sensing technology, information technology, bionic technology, material science, etc., which makes the concept of monitoring transition to online, dynamic, and active real-time Monitoring and control.

    5. Realize various traceability requirements

    (1) Self-calibration and self-calibration high-precision measurements require high-precision traceability. In many cases, it is difficult to find an instrument that meets the accuracy requirements. The important reason is that traceability restricts the development of measurement accuracy. In some cases, measuring instruments can be used. Calibration and virtual measurement methods to solve the traceability problem.

    (2) On-site direct calibration More and more measuring instruments require on-site direct calibration, many of which are three-dimensional spatial calibration. Development of on-site calibration technology and instruments is the key to completing these calibrations.

    (3) Nano traceability The traceability of nanometer testing is also an important issue. Foreign countries have studied the precise size of the interplanar spacing of silicon (220) crystals in the United States, PTB, and NRIM in Germany. The element lattice size has a good effect at a constant temperature. Stability can be used to establish nano traceability benchmarks.