Double-Nozzle Capillary Force Gripper for Cubical, Triangular Prismatic, and Helical 1-mm-Sized-Objects

Abstract

In this paper, we describe a novel capillary force gripper with two nozzles for the manipulation of complex-shaped micro-objects. These nozzles rapidly form constant-volume droplets and have two primary functions: fast water refilling by capillary action and fast droplet formation by the on-off control of a diaphragm pump. Capillary force is a dominant microscopic force acting on objects of all shapes owing to the fluidity of water. Therefore, it is suitable for the capture and release of heterogeneous and complex-shaped micro-objects. In the experiments, we picked and placed 1-mm cubes, triangular prisms, and helical micro springs. The positioning errors ±SD for each shape were 54 ± 36 μm, 85 ± 32 μm, and 162 ± 74 μm, respectively. These prisms and springs are difficult to control using conventional air nozzles, which have a typical positioning accuracy of approximately ± 40 μm for rectangular prismatic objects. In addition, by setting the distance between the nozzles to an appropriate value, we reduced the deviation of the attitude angle around the vertical axis to ±2.6° using self-alignment phenomena for the 1-mm cubes. The proposed method is feasible for manipulating complex-shaped and fragile micro-objects in the micro-electro-mechanical systems field.

Precise Position Control of Holonomic Inchworm Robot Using Four Optical Encoders

“…Micromanipulation requires tools to accurately manipulate objects and multi-axis positioners to move the tool to an appropriate position and orientation with a sub-micrometer resolution. Various tools have been developed, such as vacuum nozzles [ 8 ], microtweezers with force sensors [ 4 , 9 ], and grippers that use capillary force [ 10 , 11 ]. Regarding the multi-axis positioner, the combination of a single-axis stage driven by linear synchronous motors with linear guides and stepping motors with ball-screw mechanisms are widely used in the industry [ 12 , 13 ].…”

Experimental investigations of liquid bridge rupture between a sphere and a spherical concave

“…The trend of miniaturization in biomedicine [5] and micro-electro-mechanical system [6] is inevitable, requiring the manipulation of microcomponents. The manipulation method based on the capillary force has many advantages, such as good cushioning due to the damping effect of the liquid bridge [7], compatibility with complex shaped objects [8], and self-centering [9]. When the separation distance between two solid surfaces reaches a critical value, the liquid bridge breaks.…”

A Predictive Model of Capillary Forces and Contact Diameters between Two Plates Based on Artificial Neural Network

“…In a further study [14], the orientation of the rectangular micropart was related to the gripper tip shape quantitatively. A double-nozzle gripper was developed to pick up the microparts with different shapes, such as cubes, triangular prisms and helical springs [15].…”