New π spring for piezostack-driven jetting dispenser

Abstract

With the rapid development of the microelectronics industry, industrial applications have put forward higher requirements on the efficiency and reliability of the dispenser, and the traditional piezoelectric dispenser uses ordinary spring preloading way, in this way, the dispenser is difficult to obtain a higher dispensing frequency, because of to the wear and tear between the connecting components and the subsequent response. In this paper, a new type of wire cutting π type spring is designed and manufactured, which solves the problem that traditional piezostack dispensers can not get the high operating frequency. In the structural design of π type spring, the stiffness of the reset spring is studied, and the output displacement characteristics of the reset spring are verified. Finally, we established the glue test system, and the point spray test is carried out on the fuse breaker and glycerol alcohol mixture at its operating frequency of 666 Hz. The mass of the fuse is measured by an electronic scale and its mass distribution is 3.08 mg (±2.5%). The diameter of the glycerol alcohol mixture sprayed by dispensing can reach 217.3 µm. By analyzing the mass and size of the glue point, it is verified that the piezoelectric dispenser with π-type reset spring can achieve high-frequency dispensing accuracy and small drop size.