High and low temperature test chamber: suitable for high and low temperature reliability test of industrial products. Test the performance indexes of parts and materials of electronic and electrical engineering, automobile and motorcycle, aerospace, ship weapons, colleges and universities, scientific research institutions and other related products under the condition of cyclic change of high temperature and low temperature (alternating).
The product has a wide temperature control range, and its performance indexes meet the technical conditions of national standard gb10592-89 high and low temperature test chamber, which is applicable to GB2423 1、GB2423. 2 environmental test for electrical and electronic products test a: low temperature test method, test B: high temperature test method conduct low temperature, high temperature test and constant temperature heat test for products. The product complies with GB2423 1、GB2423. 2、GJB150. 3、GJB150. 4. IEC and mil standards.
Basic information of high and low temperature test chamber:
The high and low temperature test chamber product can simulate the temperature change law in the atmospheric environment. It is mainly aimed at the adaptability test of electrical and electronic products, as well as their components and other materials during transportation and use under the comprehensive environment of high temperature and low temperature. Used in product design, improvement, identification and inspection.
This index is also called temperature stability, which controls the difference between the maximum and minimum temperature at any point in the workspace within a given time interval after the temperature of the high and low temperature test chamber is stable. There is a small difference here. The "workspace" is not a "studio", which is about 1 / 10 of the length of the studio from the respective sides of the box wall. This indicator assesses the control technology of the product.
It refers to the limit temperature that the product high and low temperature test chamber can withstand and / or reach. It usually contains the concept of constant control, which should be the extreme value that can operate stably for a relatively long time. The general temperature range includes extreme high temperature and extreme low temperature.
The index required by the general standard is ≤ 1 ℃ or ± 0.5 ℃.
The old standard is called uniformity, and the new standard is called gradient. After the temperature is stable, the maximum value of the difference between the average temperature values of any two points in the workspace in any time interval. This index can assess the core technology of the product better than the following temperature deviation index. Therefore, many company samples and schemes deliberately hide this item. Guangdong Liyi Technology Co., Ltd. resolutely protects the interests of customers.
The index required by the general standard is ≤ 2 ℃.
After the temperature is stable, the difference between the average temperature of the center of the working space of the high and low temperature test chamber of Guangdong Liyi Technology Co., Ltd. and the average temperature of other points in the working space at any time interval. Although the definition and title of this indicator are the same in the old and new standards, the detection has changed. The new standard is more practical and harsh, but the assessment time is shorter.
The index required by the general standard is ± 2 ℃, and the actual operating temperature (℃) ± 2% can be used for pure high temperature test chamber above 200 ℃.
The selection of environmental and reliability test equipment shall follow the following five basic principles:
1. Reproducibility of environmental conditions:
It is out of reach to completely and accurately reproduce the environmental conditions existing in nature in the high and low temperature test chamber of Liyi. However, within a certain tolerance range, people can correctly and approximately simulate the external environmental conditions experienced by engineering products in the process of use, storage and transportation. This paragraph is summarized in engineering language, That is, "the environmental conditions around the tested product (including platform environment) created by the test equipment shall meet the requirements of environmental conditions and tolerance specified in the product test specification" 。 For example, the temperature box used for military product test shall not only meet the national military standard GJB150 3-86、GJB150. The test quantity and test time of high temperature and low temperature specified in 4-86 according to different types of products shall also meet the requirements for the uniformity of temperature field and temperature control accuracy in the test specification. Only in this way can the reproducibility of environmental conditions in environmental test be ensured.
2. Repeatability of environmental conditions:
A high and low temperature test chamber environmental test equipment may be used for multiple tests of the same type of products, and a tested engineering product may also be tested in different environmental test equipment. In order to ensure the comparability of test results of the same product under the environmental test conditions specified in the same test specification, The environmental conditions provided by the environmental test equipment must be repeatable. In other words, the stress level (such as thermal stress, vibration stress, electrical stress, etc.) applied by the environmental test equipment to the tested product is consistent with the requirements of the same test specification.
The repeatability of the environmental conditions provided by the environmental test equipment is guaranteed by the national metrological verification department after passing the verification according to the verification regulations formulated by the national technical supervision organization. Therefore, the environmental test equipment must meet the requirements of various technical indexes and accuracy indexes in the verification regulation, and the service time shall not exceed the time limit specified in the verification cycle. For example, the widely used electric vibration table must not only meet the technical indicators such as excitation force, frequency range and load capacity, but also meet the requirements of accuracy indicators such as transverse vibration ratio, table acceleration uniformity and harmonic distortion specified in the verification regulations. Moreover, the service cycle after each verification is two years. It can be put into use only after it has been verified to be qualified for more than two years.
3. Measurability of environmental condition parameters:
The environmental conditions provided by the environmental test equipment of any high and low temperature test chamber must be observable and controllable, not only to limit the environmental parameters within a certain tolerance range and ensure the reproducibility and repeatability requirements of the test conditions, but also for the safety of product test, so as to prevent the damage of the tested product due to out of control environmental conditions, Bring unnecessary losses. It is generally required in various test specifications that the accuracy of parameter test shall not be less than one third of the allowable error of test conditions.
4. Exclusivity of environmental test conditions:
In each environmental or reliability test, there are strict regulations on the category, quantity and tolerance of environmental factors, and the penetration of environmental factors not required for the test is excluded, so as to provide an accurate basis for judging and analyzing product failure and failure modes during or after the test. Therefore, in addition to providing the specified environmental conditions, the environmental test equipment is required, It is not allowed to add other environmental stress interference to the tested product. For example, the table magnetic leakage, acceleration signal-to-noise ratio and total root mean square value ratio of in band and out of band acceleration defined in the verification regulation of electric vibration table. The accuracy indexes such as random signal inspection and harmonic distortion are verification items formulated to ensure the uniqueness of environmental test conditions.
5. Safety and reliability of test equipment:
The environmental test, especially the reliability test, has a long test cycle, and the test objects are sometimes military products with high value. During the test, the testers often have to operate or test around the site. Therefore, the environmental test equipment must have the characteristics of safe operation, convenient operation, reliable use and long service life, To ensure the normal operation of the test itself. Various protection, alarm measures and safety interlocking devices of test equipment shall be perfect and reliable to ensure the safety and reliability of test personnel, tested products and test equipment.
Contact Person: Ms. Victoria Li
Tel: +86 13929216856