Dispensing process with additional ultrasonic energy

This paper deals with the dispensing of viscous materials, focused especially on thick film pastes and thixotropic materials. The main aim of our solution is to reduce the viscosity of paste and thus ensure better conditions for the deposition during deposition process. The basic classification of dispense systems into groups depends from the discharge of material. There are two main principles; the first is based on pressure actuation and the other on the screw principle. For our new developed head we have used the pressure system which allows better application of additional ultrasonic energy. New principle of ultrasonic energy application at the capillary outlet is based on piezoceramics resonator. During generation of the appropriate harmonic signal the resonator will vibrate and transferees the kinetic energy to capillary walls and thus causes the additional movement of paste. The field of printed media in the capillary section is more homogenized. If we keep constant pressure we can control the speed of material in capillary very sensitively. For dispensing systems this new principle gives good possibility for the achievement of increasing resolution for the standard materials. Our experimental work has verified decreasing of minimal required pressure by the application of additional ultrasonic energy. This paper describes the new principle and the construction of the ultrasonic dispensing head for precise dispensing of thixotropic materials including thick film pastes. Printing method can be optimize by analyze of printed profile, which is necessary part of precise option of the ultrasonic power unit.