Blister height

Thus, even though the blow-off pressure does not stay constant as the blister grows, Eq. (29), measured values can be employed with corresponding values of the blister height to calculate the strength of adhesion continuously no other parameters are needed. 

Hydrostatic pressure is applied in the hole either with a fluid (oil, mercury, etc.) or with pressurized air. The pressure is the primary measure of the debonding process. The height and diameter of the blister are measured in order to obtain the maximum stress or bonding energy (work of adhesion). From these geometrical data, together with the tensile modulus of the film and its thickness, a critical... 

Blister ring A raised portion of the root between flights of sufficient height and thickness to effect a shearing action of the melt as it flows between the blister ring and the inside wall of the barrel. 

A third case, particularly important for thin films, is where the blister radius a is larger than the layer thickness t. Fig. 24. The principal mode of deformation of the layer is then biaxial stretching, and the relationship between inflating pressure II and height y of the blister before any further detachment occurs is given by ... 

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