Design and characterization of a precision fluid dispensing valve

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.