Residual stress exists in all metal workpieces, such as those being bent, cut or stamped. Practically, annealing is often applied to relief the stress, but the side effect of annealing is deformation which will not be expected by the manufacturer. Vibration stress relief (VSR) is another effective stress relief technology. The vibration wave induces a spontaneous alternating stress in the workpiece and triggers the movement of the lattice, reducing and homogenizing the residual stress of the workpiece. 
There are different theories about how to achieve the best stress relief effect through vibration treatment; some uses the vibration frequency as the judge while others use the amplitude. This technique based on the natural vibration of the workpiece as the relief vibration wave because the material absorbs the most vibration energy to relieve the stress under natural frequency. Up to now, this technology has served many different companies and departments.

There are different theories about how to achieve the best stress relief effect. Some used the vibration frequency as the criteria; The material will absorb the highest energy when it was vibrated at certain frequency. Others considered the vibration amplitude as the key parameter; the amplitude must reach a key value to move the lattice of the material and relieved the stress. Different from the above theories, this technique takes the waveform as the key parameter. The vibration motor provides a low frequency (lower than 100 Hz) and excites a high frequency vibration (natural frequency vibration, over 1kHz) wave from the workpiece. The natural frequency vibration can trigger the movement of the lattice to relieve the internal stress.

This technology can be applied on most of the metal industries, for example:
1. Manufacturing and processing. All kinds of metal processing must contain residual stress, which is unavoidable.
2. Machine tool manufacturing. Relieving the stress will stabilize the machine tool
3. Steel structure manufacturing. The large scaled structure cannot be annealed by heating furnace, while the vibration can still be applied.
4. Casting industry. Vibration during casting can homogenize the alloy composition and improve the microstructure.
5. Welding industry. Vibration during welding has the same effect as vibration during casting. 
6.Heat treatment industry. Treating with vibration before annealing will reduce the deformation.