针对微装配/密封工程对用胶量超微化(≤1 pL)的需求, 提出了一种既适用于接触式点胶, 也适用于非接触式点胶的超微量点胶方法。采用移液针穿过装有胶液的玻璃微管, 在移液针先端吸附微小胶滴, 当移液针先端靠近点胶面时, 其先端吸附的微小胶滴与点胶面接触, 移液针离开点胶面后, 微小胶滴的一部分将残留在点胶面上, 实现超微量点胶。通过匹配点胶的参数, 实现点胶量的控制。该方法可以适用于任何黏度(1~3.5×105 cP)的胶液、任意空间方向的超精密点胶。实验讨论了移液针直径和点胶距离(移液针先端与点胶面的距离)对点胶性能(胶斑直径)的影响; 在此基础上, 匹配移液针直径、点胶距离、玻璃微管内径和点胶速度等参数, 实现了胶液黏度为971 cP, 点胶量为40 fL、170 fL、180 fL在3种亲水性不同的点胶面上的微量点胶; 以及胶液黏度为3×104 cP, 胶斑直径为243.9 μm时的超微量点胶。实验结果验证了提出方法的可行性。

To satisfy the requirement of an ultra-micro dispensing volume no more than 1 pL in micro-assembly and sealing engineering, an ultra-micro dispensing method applicable to both contact dispensing and non-contact dispensing was presented. In this method, a needle was moved through the capillary equipped with dispensing fluid and the droplet was adhered to its tip. When the needle tip approached to the target surface, the dispensing could be achieved due to the interfacial tension between the adhered droplet and the target surface. The dispensing volume could be easily controlled by matching the parameters of dispensing process. This method is suitable for any viscosity dispensing fluid ranging from 1 cP to 3.5×105 cP, and can dispense for spatial arbitrary directions. Based on an ultra-micro dispensing experiment platform built in this paper, the influences of needle diameter and gap (the distance between needle tip and target surface) on the size of dispensing spot were investigated. According to the studies, proper needle diameters, gaps, inner diameters of capillary and dispensing velocity were chosen, the ultra-micro dispensing with the volume of 40 fL, 170 fL and 180 fL was achieved when the fluid viscosity was 971 cP and the dispensing spot diameter was 243.9 μm, as well when the viscosity was up to 3×104 cP. The experimental results verify that the proposed method is feasible.