Let's first use the following picture to understand the classification of components:
Definition of components storage period:
Save TS: The components are accomplished from the production of production and check the passage before the installed environment is deposited under certain environmental conditions.
Effective storage period TVS: The component of a certain quality level is stored under the predetermined storage environment, and its batch quality can meet the requirements of the requirements.
Basic effective storage period TBVS: Effective storage period without the quality level of the component.
Storage quality coefficient CSQ: The adjustment factor of the basic effective storage period is based on the different quality levels of components.
Oversessure: More than a component of the effective storage period, a series of inspections that should be performed before the installation.
Continue the validity period: Overseas re-test components are stored under the predetermined storage environment, and their batches can meet the requirements of the requirements.
Component storage period:
The start date of the storage period of the component is usually obtained in accordance with the following principles.
1. After two (supplement) screening, its screening items and conditions are not less than the relevant predetermined overtime check, and the second (supplement) screening completion date or production date is no more than 12 months. Components can be calculated on the completion of the filtering (batch) screening (batch) screening report (batch) screening report.
2, the production date (or week) code (number) of the components (numbers), such as import device code "9908" indicates production of 1999 production; all day months without date, according to the 15th of the month ( If the week code is calculated as date on Thursday).
3. Calculated according to the test date on the product certificate.
4. Calculate in advance by pressing the package on the packaging container.
5. By the component acceptance date, two months in advance, if the date of manufacture of components can be determined when acceptors, should be calculated according to the date of production.
When the start date of the component of the component is obtained, the storage period of the component is the time from the start date of the components to the predetermined installed date.
Component effective storage period:
The effective storage of components is related to the material, structure, and storage of components. Different categories of components are different due to differences in structures, and their effective storage period will also vary. The storage period of the metad device is specified in the product specifications of some components (general specifications or detailed specifications), which are "effective storage period" to a certain extent.
The earlier US military army standard MIL-S-19500E "Semiconductor Device Total Specification" specified in stock more than 12 months, and the procedure for re-inspected when delivering the goods, which can be considered that the semiconductor discrete device is specified. "Effective Storage" is 12 months; the MIL-S-19500J released in the 1990s specified semiconductor discrete devices inventory over 36 months, and the procedures for re-testing when delivering, indicating that the semiconductor device is manufactured. The advancement of technology, the "effective storage period" of semiconductor discrete devices is also extended.
US military standard MIL-M38510 "Total Specification" of Microelectronics stipulates the "effective storage period" of microcircuits: 24 months in the 1980s, has been extended to 36 months in the 1990s. In addition, the European Space Authority (ESA) Standard ESAPSS01-60 "ESA Space System Selection, Purchase and Control" and European Space Standardization Cooperation Organization (ECSS) Standard ECSS-Q-60A "Space Products guarantees electronics, electrical and machinery The device "has specified inventory components from being made to the expected installed date of 60 months, and the retrofit program should be checked before the installation.
At present, my country's military "seven special" components, and some of the technical conditions of some yuan devices specify "effective storage period". Such as QZJ 840620 specifies that the radiofrequency plug holds in ambient temperature of 5 ° C to 35 ° C, and the relative humidity is not more than 80% of the warehouse should have usage; QZJ 840621 specifies that the quartz resonator is shipped after normal storage. Under the conditions, the frequency change within 96 months should be within the scope of the supplementary technical conditions.
Effective storage period As the quality indicators of components, it should be given by components manufacturers, and most domestic manufacturers have to do this. There is still a certain difficulty. In the case where the components manufacturer cannot be provided, it is usually based on the experience of the summary experience, and the effective storage period of the components shall be specified in the domestic and foreign experience. The effective storage of components is related to the environmental conditions stored, but the same standards in the US standard and the European space agency have not indicated 36 months or 60 months in how the effective storage period in the storage environment. This can only be understood as the warehouse environmental conditions of Europe and the United States, or have reached the storage environmental conditions equivalent to the I class. Different components have certain differences in structures and materials, so their effective storage period is not the same, and similar standardized documents similar to European spatial institutions are set to 60 months in the effective storage of components. This approach is not necessarily Very scientific. The effective storage of components is related to the quality level of components, but the quality level of the metader is not indicated in the similar standards of the US standard and the European spatial institution.
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