I.A. Lozovoy, A.V. Turetsky

To testing of reliability of solder connections in components of radio-electronic modules often apply natural tests in which to acceleration of process apply a thermocycles - endurance at big temperature drops. In the IEC/PAS 62137-3 standard process of formation of impacts on a component is in detail described and thermocycles parameters are recommended. Test is conducted before loss of electric contact, in any solder connection. After carrying out testing results are subject to processing. The IPC-SM-785 standard regulates a technique of the accelerated fail-safe tests of solder connections. Some data on statistical processing of results of tests from this standard are provided. In the given equations the parameters reflecting physical causes of failure and defining average cyclic durability are considered, and also reflect statistical distribution of refusals which is presented in the form of Veybull\'s distribution. The ratios defining number of processes of a thermocycles depending on service conditions and service life of equipment are given also. In the table information in a combination to hypothetical examples of service conditions and to use of the given equations and attraction of statistical distributions of Veybull for determination of equivalent average values of cyclic durability for modes of the accelerated tests, as for SMD solder connections of superficial installation, and for connections with conclusions is presented. These equivalent cycles of tests represent average of cycles to the full for test conditions. The obtained data allow to define limiting the characteristic of solder connections of components at the accelerated fail-safe tests and by that to predict a component exit out of operation at the set modes of operation.