In environmental and reliability testing, there are some shaking tables used for comprehensive environmental testing, and the requirements for shaking tables are different according to the factors of comprehensive environment.
1, Temperature + Vibration – environmental stress screening equipment
When the test chamber is in a high-temperature environment, the heat obtained from the circulating air on the electrodynamic shaker table will be transferred to the frame of the moving coil along the channel connecting the table and the moving coil, accelerating the “thermal aggregation” of the working of the moving coil and affecting the working temperature of the moving coil. The heat obtained from the circulating air on the hydraulic table will be transferred to the working medium – hydraulic oil along the piston spindle, resulting in a decrease in the viscosity of the oil, which in turn affects the efficiency of the hydraulic table and the working condition of the hydrostatic bearing.
When the test chamber is in a low-temperature environment, the electrodynamic vibration table surface from the circulating air in the cold will be along the table surface and the moving coil connected to the frame of the moving coil, which is conducive to the heat dissipation of the moving coil, but when the vibration table surface in a low-temperature state, if the absolute moisture content of the atmosphere is high, it will lead to exposure to the atmospheric environment of the table surface condensation, and in the process of vibration of the table surface, the condensation of water droplets spilled to the surrounding, affecting the environment of the test site, but also may enter the dynamic coil magnetic circuit of the electrodynamic shaker, bringing harm. For hydraulic shakers, in addition to the above-mentioned impact of dew, the transfer of cold will also increase the viscosity of the fluid and increase the flow damping, which will also affect the efficiency of the hydraulic table.
According to the appeal analysis, the shaker used for such equipment must be configured on the table with good thermal barrier, and at the same time also need to prevent the condensation of water in the test chamber through the bolt connection aperture directly penetrate the table, triggering a series of subsequent problems.
2, Temperature + Humidity + Vibration – reliability test equipment
Shaking table for this type of equipment also has the above analysis of “temperature + vibration – environmental stress screening equipment” of various problems, but also because of the “humidity” environment to join the “condensation” and “infiltration” problem will be more serious in the low-temperature state, and therefore the “insulation” and “waterproof” performance requirements are higher.