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Creep test glue, visco elastic materials, SMD

Time dependent deformation is an important failure mechanism. Our experience with solder has led us to develop methods for applying loads to small samples as the solder joint is the weakest connection in a printed circuit board.

The dimensional changes that occur with time when materials are statically loaded, is referred to as creep. Creep measurements are important for solders, polymers and adhesives where large strains can develop over time and strain rates are very temperature sensitive.

  • Creep measurements are important for solders, polymers and adhesives where large strains can develop over time and strain rates are very temperature sensitive
  • The applied stress can be substantially below the yield point and in all cases the time dependent deformation is due to a thermally activated process
  • Creep measurements are highly sensitivity to temperatures so that they can often need to be made at the component's operating temperature
  • In addition, creep mechanisms can only be fully characterized if measurements are made over a range of temperature and stress levels

 

Creep testCreep test

Load control is useful when you want to apply a know load or stress.

The load is always maintained, even if the sample creeps. As the load approaches the target load, the axis slows down to avoid overshoot. During the hold period load is maintained by constantly adjusting the axis position.

 

 

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