High precision self-alignment using liquid surface tension for additively manufactured micro components
journal contributionposted on 27.05.2016 by J.K. Overton, Peter Kinnell, Simon Lawes, S. Ratchev
Any type of content formally published in an academic journal, usually following a peer-review process.
Self-assembly of components using liquid surface tension is an attractive alternative to traditional robotic pick-and-place as it offers high assembly accuracy for coarse initial part placement. One of the key requirements of this method is the containment of the liquid within a designated binding site. This paper looks to expand the applications of self-assembly and investigates the use of topographical structures applied to 3D printed micro components for self-assembly using liquid surface tension. An analysis of the effect of edge geometry on liquid contact angle was conducted. A range of binding sites were produced with varying edge geometries, 45-135°, and for a variety of site shapes and sizes, 0.4 - 1 mm in diameter, and 0.5 x 0.5 – 1 x 1 mm square. Liquid water droplets were applied to the structures and contact angles measured. Significant increases in contact angle were observed, up to 158°, compared to 70° for droplets on planar surfaces, demonstrating the ability of these binding sites to successfully pin the triple contact line at the boundary. Three challenging self-assembly cases were examined, 1) linear initial component misplacement >0.5 mm, 2) angular misplacement of components, 3) 2 misplacement of droplet. Across all three assembly cases the lowest misalignments in final component position, as well as highest repeatability, were observed for structures with actual edge geometries <90° (excluding 45° nominal), where the mean magnitude of misalignment was found to be 31 μm with 14 μm standard deviation.
The authors would like to acknowledge the generous funding provided by the Engineering and Physical Sciences Research Council EPSRC that has made this research possible.
- Mechanical, Electrical and Manufacturing Engineering