FUNDAMENTALS OF ULTRASONIC WELDING
AEROPROJECTS INC WEST CHESTER PA
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Photoelastic investigations show that ultrasonic welds are initiated as a result of vibration-induced interfacial shear stresses combining with the interfacial shear stresses resulting from the normal clamping force to produce ALTERNATELY, ON THE SIDE TOWARD WHICH THE VIBRATORY FORCE ACTS, ISLANDS OF LOCAL SLP WITHIN AN AREA OF ELASTIC STRAIN. A proper clamping force is productive of a best impedance match to effect energy delivery into the weld locale. Sheet thickness and the Vickers microhardness indentation number are combined to permit a first approximation of the energy required to produce welds between metallic sheets. Bonds are not uncommonly characterized by internal deformations without significant external deformation. The temperature achieved during vibratory welding is measured to be in the range of about 35 to 50 of the absolute melting temperature. No evidence of melting was observed in any monometallic weld.