Image Number 2 for United States Patent #6138562.
Solder Paste, adhesives and other materials are screen printed onto Printed Circuit Boards (PCB's) during the assembly process for electronic circuit assemblies. Pressure forces may be applied to the material to aid in separating the material from the apertures within the stencil. The pressure forces are created from sound pressure waves generated from a vibrational energy source located some distance from the stencil. Examples of non-contacting vibrational energy sources include Ultrasonic transducers, horns, speakers, and tuning forks. Additional assistance to separate the material from the apertures may be applied by a vibrational source by contacting to the stencil. Examples of the contacting vibrational energy sources may be off-balanced motors, piezo-electric transducers, and mass-resonant vibrators.