33 results about "Environmental stress screening" patented technology

The invention discloses an environmental stress screening method of an electronic device by using stepping stress. A screening system comprises a temperature box, a vibrating table and a test device. According to the method, electronic devices which are invalid early are removed by using stepping stress, and a mode of only exerting constant temperature circulation or constant vibration stress in a previous screen method is changed; meanwhile, a combined stress screening method is firstly adopted. By exerting environment screening stress of stepping stress and combined stress to the electronic device, the screening validity and the screening effect of environmental stress are effectively increased. The environmental stress screening method is successfully implemented in a product of a certain type, the delivered electronic device passes the check of actual application, which proves the validity and the applicability of the control method; thus, the environmental stress screening method has strong generalization performance during the production process of electronic devices.

A virtual oven efficiently conducts stress testing of large numbers of modules. The virtual oven includes a logical grouping of modules, a controller, test instruments and a database which are all connected via a network. The logical groupings of modules of several virtual ovens may be physically accommodated within a single environmental stress screening room. Switching between modules in a logical group permits a single test piece of test equipment to be time-shared among the modules in the logical group. The method of bum-in testing a logical group of modules rotates a test sequence, including passive and active test cycles, between the modules. A test signal is split and supplied to multiple modules. Passive testing may be performed by monitoring parameters of the module while the test signal is supplied to the module. Active testing may be a functional test of the module in which the test signal is supplied to, processed by, and output from the module. Such test signals output from the modules are switched to the test equipment on a time-share basis. In this way, the number or expensive test equipment set-ups may reduced. The controller for each virtual oven also generates displays so that a user can track the test progress of all modules within the virtual oven. The controller also builds a database of the active and passive tests for each module. A graphical user interface may be used to interact with the virtual oven, control the testing, and view the database.

The invention discloses a rapid temperature change test box, and belongs to the field of environmental stress screening test equipment. The rapid temperature change test box comprises a box which comprises a box body and separating layers which separate the internal part of the box body into three intervals. The three intervals are a work room, a refrigerating room and a power distribution room in turn. The work room is internally provided with an axial flow blower. The power distribution room is internally provided with a motor driving the axial flow blower. Magnetic transmission is adopted between the motor and the axial flow blower. Magnetic transmission is adopted between the motor and the axial flow blower, and a through hole does not need to be arranged on the box between the motor and the axial flow blower for arrangement of a transmission shaft so that a box sealing performance problem caused by existence of the through hole can be avoided, and box sealing performance can be enhanced. With increasing of sealing performance, moist air exchange inside and outside the test box is reduced, and humidity in the box is relatively low in the test process so that influence on the test result caused by condensation on the product can be avoided and accuracy of the test result can be enhanced.

The invention relates to a BGA (ball grid array) welding point acceleration service life prediction method, which comprises the following steps that (a) n BGA welding point samples are randomly selected, wherein the n is greater than or equal to 5, and the BGA welding point samples are subjected to environment stress screening processing; (b) the samples processed in the step (a) are subjected to integral stress processing, and the integral stress processing comprises second temperature circulation processing, random vibration processing and electric stress processing on the samples processed in the step (a), and in addition, the sample failure time is recorded; (c) the samples processed in the step (b) are subjected to third temperature circulation processing; (d) a model shown in a formula (III) is used for calculating an acceleration factor, and finally, a formula (IV) is used for calculating the use average failure before time MTTR<use> for predicting the service life of the BGA welding point. The invention also provides application of the method to the preparation of electronic products and mechanical equipment.

The invention discloses an environmental stress screening test and forecasting repair comprehensive optimizing method, which comprises a planning stage and an executing stage; the planning stage includes three steps which are environmental stress screening test modeling for many times, repair element confirming module and environment stress screening test, and preventive repair planning comprehensive optimization; the executing stage includes the implementation of environmental stress screening test and the predicting repair planning and execution. The method comprehensively considers the environment stress screening effect and the screening cost before the product is put into use, and the influence of the selection of the repair time on the repair cost after the product is put into use; before the product is put into use, the environmental stress condition and the test frequency are comprehensively optimized and selected on the basis of the environmental stress screening test model and the forecasting repair planning model; after putting the product into use, the preventive repair time of is optimized according to the state monitoring data of every product in use after the productis put into use; the method can effectively reduce the total cost of screening and repair.

The invention discloses an environmental stress screening test method and device, and aims at improving timeliness and effectiveness of environmental stress screening test. The method comprises that temperature stresses are applied according to a preset cycle index, and each time the temperature stress is applied, a first heating operation, a first high temperature maintaining operation, a second high temperature maintaining operation, a cooling operation, a first low temperature maintaining operation, a second low temperature maintaining operation and a second heating operation are executed successively; when the temperature stress is applied for the first time, a vibration stress is applied while the second high temperature maintaining operation and the second low temperature maintaining operation are executed; and each time the temperature stress is applied, an electric stress is applied. Thus, the environmental stress screening test can be completed in one test with once establishment of a test environment, three types of stresses are applied at the same time, defects in an integrated stress state can be screened, and the test timeliness and effectiveness are improved.

The invention discloses an environmental stress screening time optimizing method and environmental stress screening time optimizing equipment for an electronic product, and belongs to the field of reliability tests of electronic products. Environmental stress screening is an important means for eliminating early failures of a product, and is achieved by applying an appropriate environmental stressto the product before leaving a factory and eliminating potential defects so as to guarantee using reliability of the product. Implementation of the environmental stress screening can reduce the maintenance cost after the product is put into use while the production cost is increased. During the environmental stress screening, component-level and assembly-level screening cost is fully considered,and especially calculation of time and expense cost is introduced, so that the screening time cost is fully considered during the environmental stress screening, and while the design reliability is improved, the screening time is shortened and the production cost is reduced so as to improve the economic efficiency and the production efficiency of an enterprise.

This invention provides a realization of environmental stress screening dynamic electronic equipment and methods, in particular: When activated, electronic equipment, have read prior instructions and the preservation of the screening information, in accordance with instructions Screening Information Executive Environmental Stress Screening procedures, in order to achieve electronic equipment own environmental stress screening. Application of this invention program, as in the electronic equipment prior to the commencement of electricity can be generated automatically screen instructions and identification information, electronic equipment, electric start, the screening can be directly under the instructions of information automatically implementation of environmental stress screening procedures, without manual intervention, so as to achieve electronic equipment dynamic environmental stress screening purposes.

The invention relates to an anti-sliding brake control box high-acceleration stress sieving method. Three comprehensive test devices are adopted, working currents are added into an anti-sliding brake control box in a test scheme, stoppage is stimulated under the common action of environment stress and the working currents and a more comprehensive improvement measure is obtained. The green effects of saving resources and time are achieved in developing the anti-sliding brake control box. By means of a high-acceleration stress sieving test profile of the anti-sliding control box, data formulating is achieved according to a high-acceleration service life test. A formulation principle is that stoppage of the anti-sliding brake control box is sieved without damaging the anti-sliding brake control box. Under the conditions, the high-acceleration stress sieving profile is composed of high temperature, low temperature, temperature vibration, vibration and the working currents. Effectiveness and safety of the test profile are verified and then the test profile can be applied to high-acceleration environment stress sieving in production to replace normal sieving in GJB1032 electronic product environment stress sieving.