Benny

I wouldn't know a standard test method but I am somewhat critical about
shear testing of solder joints because of the following points:

- The forces you measure depend very much on the speed of the deformation
you apply. Maybe the folks I heard so far working with this test methods
where not the best informed ones, but I never heard somebody mentioning
this test parameter.

- The same applies to the thickness of the solder layer you are testing,
since the stress necessary to induce a certain deformation speed depends on
the strain rate which is the speed of deformation divided by the layer
thickness. The thickness of this layer varies between 2 and 30um.

- The deformation speed also influences the evolution of damage in solder.
This means, in my opinion, that you never now how big the load bearing area
was at the moment of fracture.

- The point where the force is applied influences your result. You will for
sure induce not pure shear stress but also tensile stress to varying
extends, depending on where on the component the force is applied.

Because of these reasons, I believe, that shear testing of soldered joints
of components only gives an extremely rough impression of the quality of a
solder joint and is not a very suitable method to evaluate the quality of a
solder production.

Best regards

Guenter

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