Design and characterization of a precision fluid dispensing valve

Abstract

Precision fluid dispensing is a complicated but yet relevant process where fluid is dispensed in a controlled manner. It is important and applicable in an array of applications ranging from dispensing of food products, biomedical applications to dispensing of adhesive and encapsulants in the semi-conductor industry. This paper discusses the design and characterization of a precision fluid dispensing hybrid valve based on the time-pressure, positive displacement pump, and adhesive jetting technologies. The main advantage of this dispensing method is that the amount of fluid dispensed is independent of the standoff height and does not rely on surface tension between the substrate and the fluid for clean dispensation. Specifically, the dispensed fluid is jetted from a fixed needle height, and hence, repeatability and accuracy is improved while eliminating vertical travel. A prototype valve was built and tested for precision and accuracy of milligrams over a range of pressures and time. The test results are promising, indicating high repeatability and accuracy for low to medium viscous materials and are comparable to existing commercially available precision dispensing systems.

Experimental study on high viscosity fluid micro-droplet jetting system

“…It has been widely used in various packaging processes in the electronics manufacturing industry [1]. Selective dispensing of fluid onto electronic packages without physical contact in a reliable and consistent manner seems to be a natural alternative to traditional mass transfer methods that are invasive and lack of consistency [2,3]. There is an evolution in the fluid dispensing technology from contact methods such as Stencil printing to noncontact micro-droplet jetting technology, which is data-driven, noncontact, and is capable of precise deposition of picoliter volumes at high rates, even onto non-planar surfaces.…”

Microdroplet generation in gaseous and liquid environments

“…This disposability allows dispensing of a wider variety of droplet liquids because cleaning or maintaining the syringe after use is not a concern. Operationally, time/pressure dispensing is flexible because a variety of planar patterns and droplet sizes can be created by modifying operational parameters instead of hard tooling (Nguon and Jouaneh 2004). Disadvantages of time/pressure dispensing include their extreme sensitivity to temperature change (depending on the droplet liquid) and syringe depletion.…”

“…As opposed to time/pressure displacement, the volume dispensed by a TPDP droplet generator is fixed by the geometry of the piston, making it relatively immune to changes in viscosity. The piston can be actuated by an electric motor or a solenoid valve and compressed air (Nguon and Jouaneh 2004).…”

“…This pneumatic droplet generator design is more common because the pressure source acts in a single direction through the device. Pneumatically actuated droplet generators have been designed where the pressurized air either directly controls the fluid (Amirzadeh Goghari and Chandra 2008;Koltay et al 2002) or moves an intermediate piston in the droplet generator (Nguon and Jouaneh 2004).…”

Identification of Operating Parameters Most Strongly Influencing the Jetting Performance in a Piezoelectric Actuator-Driven Dispenser

“…Thus, fluid dispensing is an important process in the electronic manufacturing industry for areas such as integrated circuit (IC) chip encapsulation, surface mount technology (SMT), and light-emitting diode (LED) packaging [1,2]. Currently, several types of dispensers have been developed and successfully applied in the field.…”