Analyze the future direction of precision testing technology

The development of advanced technology is changing rapidly, and precision testing technology should adapt to this development. The role of precision testing technology in mechanical science is to serve the advanced manufacturing industry and shoulder the heavy responsibility of quality technology assurance. This requires that the first step is to improve the quality of the product as a starting point, which is also to achieve the most important purpose.

Secondly, precision testing technology should improve the production efficiency of products. Therefore, the testing method should be able to adapt to the requirements of rapid development of production, can not be purely for testing and testing, not because of the testing requirements and affect the efficiency of production, from a more positive point of view, should be due to the good service of precision testing technology to promote the improvement of production capacity. According to the requirements of advanced manufacturing technology development and the development law of precision testing technology itself, new measurement principles and test methods, as well as test information processing technology, as far as mechanical disciplines are concerned, the following aspects are expected to need to be developed.

1, visual testing technology

There are many contactless testing techniques, especially visual testing techniques. The development of modern visual theory and technology lies not only in simulating the functions that the human eye can accomplish, but more importantly, it can accomplish the work that the human eye is not competent for, so visual technology, as the latest technology, has developed rapidly on the basis of the continuous maturity and perfection of electronics, optics and computer technology. Visual testing technology is a new test technology based on computer vision research. Unlike the visual pattern recognition and visual understanding of computer vision research, visual testing technology focuses on the geometry of objects and the position measurement of objects, such as the measurement of three-dimensional dimensions of the white body of a car, the rapid measurement of three-dimensional face shapes such as molds, the coaxial measurement of large work parts, and the measurement of common face. It can be widely used in online measurement, reverse engineering and other active, real - time measurement process. Visual testing technology is growing rapidly abroad, and as early as the 1980s, the U.S. National Bureau of Standards predicted that 90 percent of the testing tasks would be performed by visual testing systems. In the 1980s, more than 100 companies in the United States entered the market for visual testing systems, which showed that visual testing systems are indeed promising. At the Beijing International Machine Tool Expo in October 1999, we have seen foreign instruments developed using visual detection technology, such as mobile optical three-coordinate measuring machine, high-speed and high-precision digital scanning system, non-contact optical three-coordinate measuring machine and other advanced instruments.

2, zero waste production measurement control

In the manufacturing industry, the ideal goal of quality assurance is to carry out the production of zero waste manufacturing. In the process of achieving this goal, the role and significance of precision testing technology is self - evident. Parts processing quality, assembly quality of the machine are related to processing equipment, test equipment and test information analysis and processing, so the realization of zero waste production, from the point of view of precision testing, the following issues should be considered: (1) before processing work parts, the prior detection of machine tools. How to verify the processing equipment quickly and accurately and obtain the accuracy of the machine tool is very beneficial to reduce rework and even eliminate rework. Of course this includes research and development of testing equipment. (2) In-line measurement of work parts or 100% detection of work parts during the production process, which requires research suitable for dynamic or quasi-dynamic test equipment, and even special test equipment can be integrated into processing equipment, real-time testing, according to the test results constantly modify process parameters, processing equipment for supplementary adjustment or feedback control. From the aspect of precision theory, we should also study dynamic precision theory, including the evaluation of dynamic precision. (3) Study how to make full use of measurement information to achieve zero waste production. By making full use of 100% on-line measurement data, the dynamic characteristics of error distribution during processing and measurement are analyzed, and the basic theoretical model of zero waste manufacturing is given according to the dynamic characteristics of processing error and the accuracy loss characteristics of sensor accuracy, as well as product quality requirements and tolerance regulations. Make full use of artificial neural network, genetic algorithm and other modern mathematical methods to accurately predict the quality of processing, so as to achieve quality ahead of the control.

3, measuring size continues to develop to two extremes

The so - called two extremes refer to the large size and small size relative to the current measurement size. Usually 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 and urgent need of the national economy, so that many aspects of production and engineering testing requirements beyond the scope of our testing, such as aircraft shape measurement, large mechanical key components measurement, high-rise building elevator rail grammatical measurement, on-site calibration of oil tankers, etc. are required to be able to carry out large-size measurement;

(1) Large-size measurement methods such as engineering geodesy means transplanting and improving some principles and methods of geodesy into mechanical engineering measurements, resulting in new measurement methods, and other methods of measuring large-size measurements, such as laser tracking interference 3D dimensional measurement systems.

(2) Nano-testing technology from the trend of production and manufacturing, every ten years requires a reduction of 1/3 of the tolerance error, so the measurement is required to have increasing accuracy, and traceable to international standards (ISO). Of course, nano-measurement is also diverse, there are optical interferometers, quantities Sub-interferometers, capacitive micrometers, X-ray interferometers, frequency-tracked Faber standard gauges, scanning electron microscopes (SEMs), scanning tunnel microscopes (SMs), atomic force microscopes (AFMs), molecular measuring machines M3 ( molecularmeasuringmachine, etc.

4, measurement methods to diversify the development

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

Because multi-sensors are used to obtain information in different ways or from different angles, they can be combined with information between them to de-authenticity and improve measurement accuracy.

(2) the building blocks, combined measurement method white body 3D dimension measurement system belongs to this kind of method, it can also be said that it is very flexible special coordinate measuring machine, the key lies in the establishment of the system.

(3) Portable measuring instruments such as portable fiber optic interferometers, portable multi-range 3D measurement systems, etc. are often used to solve large-size measurement problems in the field.

(4) Virtual instrument virtual instrument is the application of virtual reality technology in the field of precision testing, which has been studied in depth in China. One is to virtualize a variety of digital test instruments into a digital intelligent test instrument supported by computer hardware, and the other is to study virtual measurements in virtual manufacturing, such as virtual measuring blocks, virtual coordinate measuring machines and so on.

(5) Intelligent structure it belongs to structural detection and fault diagnosis, is a fusion of intelligent technology, sensing technology, information technology, bionic technology, materials science and other interdisciplinary disciplines, so that the concept of monitoring transition to online, dynamic, active real-time monitoring and control.

5, to achieve a variety of traceability requirements

(1) Self-calibration, self-calibration of high-precision measurement requires high-precision traceability, in many cases it is difficult to find instruments to meet the requirements of precision, the important reason is that traceability restricts the development of measurement accuracy, in some cases, the calibration and virtual measurement methods of measuring instruments can be used to solve the traceability problem.

(2) On-site direct calibration more and more measuring instruments require on-site direct calibration, many or three-dimensional spatial calibration, the development of field calibration technology and instruments is the key to complete these calibration.

(3) The traceability of nano - traceable nano - testing is also an important issue. Foreign countries have the United States NIST, Germany PTB, Japan NRIM study silicon (220) crystal wafer spacing accurate size, elemental lattic size at constant temperature has a good stability, can be used to establish nano-traceability benchmark.