The self-assembly of microscale polyhedra driven by surface-tension constraints has been previously described in the literature. Lithographic techniques were used to fabricate two-dimensional structures that, when freed from the underlying substrate, folded into polyhedral shapes. In this article, a modified technique is described in which one face of each polyhedron remains attached to the silicon substrate. The advantage of this new approach is that precise arrays of polyhedra can be formed. Five different polyhedral shapes were fabricated and their corresponding yields are given. The yield values show that the success of the autofolding process depends on the shape of the three-dimensional structures. Truncated shapes appear to be the most readily assembled.

Recently, soldering has been used to assemble three-dimensional microscale structures. Solder is deposited on adjacent metallic faces of planar polyhedral patterns, bridging the small gaps between individual faces. When all but one face of a polyhedral pattern are freed from the substrate and solder is reheated to a liquid state (reflow), the free faces of the pattern fold upward, out of the plane, to form the desired polyhedron. The wetting of solder with regards to coverage of metallic faces has been described previously, but the lateral bridging between the metal faces remains relatively unexplored. The goal of this work is to characterize the parameters influencing the bridging and folding process for two different ways of dip soldering: face and edge soldering. Face soldering refers to the complete wetting of metal faces, whereas edge soldering refers to selectively applying solder on the edges of a face that come in contact with other faces when folded. Our work explores bridging yield for various gap spacings and face thicknesses for eight different polyhedral patterns. Experiments show that the thickness and gap spacing strongly influence successful bridging. Experiments also show that improved control over the bridging process increases the yield of folded structures. In particular, gap spacing is positively correlated to face thickness for successful folding. Moreover, face soldering results in higher yields than edge soldering for all patterns.

Dip-soldering is a crucial step in forming certain self-assembled metal structures. However, this particular use of dip-soldering is not well described in the literature. The goal of this work is to characterize the thickness and roughness of solder layers deposited by dipping metallic films into solder melt over a range of temperatures. Control of the solder thickness and roughness will improve the yield of structures whose self-assembly is driven by surface area minimization during solder reflow. Film thickness and overall film roughness for four solder alloys, each with different melting points, were measured on unpatterned and patterned copper films. Additionally, two variations in flux treatment were investigated: flux maintained at room temperature and flux heated to 98 °C. Findings include the determination of critical temperatures, particular to each alloy, above which the roughness and thickness of the deposited solder dramatically decreases. Preheating the flux improves the nature of the deposition below these critical points. Above the critical points, thickness and roughness of the solder vary little and heating the flux does not provide significant improvements. This study provides insight into designing a process flow that optimizes the folding characteristics of self-assembled metal polyhedra by controlling the volume and quality of the solder layer.

A graphical programming tool is developed in a view to help beginners realize the importance of coding in the form of physical robotic movement. Introducing a programming language to students with no background is often felt to be challenging in terms of syntax and control flow of a language. The paper discusses an open source graphical programming tool built on Minibloq platform that allows students to focus more on creative part of programming. The paper proposes a graphical approach to programming where a student need not remember any constructs of a programming language, but relies on the approach to solve a problem. The programming utility is developed for an open source Arduino platform. Currently the tool is developed to control a real robot built around Arduino platform. Thus a platform to learn fundamentals of programming as well as robotics is made available to students. The graphical programming tool with the robotic hardware was found to be easy to learn by high school students during an outreach program conducted by the authors. The framework is also extendable beyond programming and can be further developed to understand robotics.

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Stereotactic techniques are used in a wide range of neurosurgical procedures. The procedures demand a high degree of spatial accuracy and minimal error. There are diverse functional surgeries that require stereotactic procedures, including deep brain stimulation, brain biopsies, and epilepsy procedures. Though the disease processes are diverse, all these procedures require accurate targeting of deep structures without visual guidance. The use of robots for stereotactic procedures is a natural progression in the surgeon's quest for higher accuracy and lower complications. This paper reviews the role of robots in stereotactic procedures and outlines current status of robots in stereotactic procedures. The shortcomings of current systems and an outline of an ideal stereotactic device are presented.

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