Analysis of non-metallic material detection technology in automobile
The properties and processing techniques of non-metallic materials are evolving every day, which leads them to be used in automobiles at a unprecedented speed. The average consumption of non-metallic materials per car has increased from 68.4 kg in 1981 to 150-180 kg today. At the same time, the market has put forward higher requirements for testing the corresponding properties of these materials, such as the impact of condensation of volatile substances from automobile interior materials on the windshield on driving safety. from the driver, the breathability of plastic fuel tanks. , inner tubes, safety The barrier property of the airbag and so on. In response to these problems, corresponding test methods, test standards and test instruments have also been introduced and continuously updated.improved.
1. Atomization detection of interior parts
Automotive interior decoration materials, such as engineering plastics, textiles, leather, non-wovens, etc., and installation. The different adhesives used in these materials, under the action of high temperature, their volatile components evaporate and form condensation on car windows or windshields. , leading to poor vision of drivers and seriously affecting driving safety. At present, foreign countries have already tested this aspect, and the relevant testing standards followed are IN75201, ISO6452, SAEJ1756, etc. Some domestic automobile and interior parts manufacturers have also paid enough attention to relevant testing, either to improve product quality or expand their businesses. Overseas markets.
There are two test methods for detecting fogging on parts interiors: the gloss test method and the weight test method. The first measures the atomization characteristics of the test sample through the change of gloss of the glass plate before and after atomization; the latter measures the quality of the atomized condensate thanks to the change in mass of the aluminum foil before and after atomization. In addition, the “nebulization value” or “atomization-condensation mass” obtained through the test can also quantitatively obtain the volatilization of toxic and harmful substances in the sample; thanks to testing the fogging value of the xenon lamp in front of the car, possibility of testing to what extent the fogging of the headlights affects the lighting.
Atomization testing equipment currently sold in the Chinese market includes brands such as German Huck and Chinese Jinan Languang.
2. Tests of air and humidity permeability of the materials of theseats
During long journeys, drivers and passengers often have to sit in the car for several or even dozens of hours, which makes it possible to evaluate the air permeability performance and to moisture in car seat materials. are higher than elsewhere. Good seat cushions and chairs should be soft and elastic, and have good air and moisture permeability, so that the sweat of drivers and passengers can be discharged smoothly, allowing people to to feel comfortable.
The air permeability testing method is: take a sample of specified size and place it in the testing chamber, vent to one side of the sample, so that a certain pressure difference forms on both sides of the sample. , and measure under this pressure difference Calculate the air permeability by the gas flow passing through a given area of the sample hangsant a certain period of time; or hold the flow through the sample and measure the pressure difference on both sides of the sample, calculate the airflow resistance. This test method follows GB/T10655-2003.
The method of detecting moisture permeability is as follows: sandwich the sample between the dry and wet chambers at a constant temperature. The sensor located in the test chamber analyzes the humidity changes in the chamber and tracks the change from the preset lower limit value to the upper limit value. The time required, through continuous multiple measurements and system analysis, to obtain the moisture permeability and moisture permeability coefficient of the sample. This test method follows the ASTME398 standard.
Third, measuring the breathability of plastic fuel tanks
Currently, the utilization rate of plastic fuel tanksplastic fuel in Chinese cars reached 86%. Compared with steel fuel tanks, plastic automobile fuel tanks are safer, corrosion resistant and have a longer service life. They also have random shapes and low production costs. However, the barrier properties of automobile plastic fuel tanks are poor, which will lead to penetrating fuel volatilization. Its barrier properties must be tested to select the ideal material.
The traditional testing method is: after injecting a certain amount of gasoline into the fuel tank, sealing it, weighing the fuel tank to obtain its mass M1, and after left for a sufficient period of time (usually more than 100 days), weigh it again to obtain it\'s mass M1. Mass M2, calculate △M=M1-M2, △M is the volatilization offuel. This method requires a long testing time and requires high-precision weighing tools, which is difficult to implement.
ASTMD3985 gives another test method. Cut plastic sheets in the fuel tank, measure the oxygen permeability of the sheets, and compare the oxygen permeability of various plastic sheets to scientifically and quickly determine which plastic has the best barrier properties and is the most suitable for making fuel cans. ASTMF1307 gives the test method of the whole container, thus realizing the leak detection test of the whole fuel tank.
4. Testing the gas barrier properties of inner tubes and airbags
Both materials used in the manufacture of automobile inner tubes and airbags require good barrier properties, and the former ensures that the car drive for a long timeps without inflating, and the second ensures that it can quickly inflate at the time of an accident or collision. of course a certain pressure.
The traditional test method is to inflate the finished inner tube or airbag to a certain pressure, record the pressure gauge reading at that time, and after leaving it for a certain time, observing the pressure drop of the pressure gauge value to obtain its barrier performance. This type of detection method usually takes a long time to get the result (sometimes more than a year) and is difficult to implement. Now you can use the gas permeability VAC-V1 produced by Jinan Languang Mechanical and Electrical Technology Co., Ltd. to take a sample of the material to be tested and fix it on the instrument in order to maintain a constant pressure difference on both sides of the sample to measure the penetration of gas through the test. The change in pressureon with time after sampling can be used to obtain the barrier performance of the material. Generally, the test in this area can be completed within 12 hours on the instrument, which greatly improves the work efficiency.
V. Detection of other non-metallic materials
There are many non-metallic materials used in automobiles, and the same material is used in different parts have different performance requirements and various test items are required. Such as tensile strength, tear strength, hardness, bending strength, color, coefficient of friction, etc.
In addition, a large number of various adhesives are used in cars. The performance of adhesives has a vital impact on the quality of the vehicle, which is why this type of non-metallic materials must be cut. Cutting, stretching, tearing and other performance tests. </p
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