Using water-soluble additive manufacturing for cheap and soft silicon organ models

Author(s):  
Daniel Reichard ◽  
Markus Gern ◽  
Hannes Kenngott ◽  
Beat Müller-Stich ◽  
Christian Pylatiuk ◽  
...  
2020 ◽  
Vol 117 (44) ◽  
pp. 27204-27210 ◽  
Author(s):  
Yong Hu ◽  
Zipeng Guo ◽  
Andrew Ragonese ◽  
Taishan Zhu ◽  
Saurabh Khuje ◽  
...  

Molecular ferroelectrics combine electromechanical coupling and electric polarizabilities, offering immense promise in stimuli-dependent metamaterials. Despite such promise, current physical realizations of mechanical metamaterials remain hindered by the lack of rapid-prototyping ferroelectric metamaterial structures. Here, we present a continuous rapid printing strategy for the volumetric deposition of water-soluble molecular ferroelectric metamaterials with precise spatial control in virtually any three-dimensional (3D) geometry by means of an electric-field–assisted additive manufacturing. We demonstrate a scaffold-supported ferroelectric crystalline lattice that enables self-healing and a reprogrammable stiffness for dynamic tuning of mechanical metamaterials with a long lifetime and sustainability. A molecular ferroelectric architecture with resonant inclusions then exhibits adaptive mitigation of incident vibroacoustic dynamic loads via an electrically tunable subwavelength-frequency band gap. The findings shown here pave the way for the versatile additive manufacturing of molecular ferroelectric metamaterials.


2017 ◽  
Vol 9 (14) ◽  
pp. 12324-12331 ◽  
Author(s):  
Allison M. Pekkanen ◽  
Callie Zawaski ◽  
André T. Stevenson ◽  
Ross Dickerman ◽  
Abby R. Whittington ◽  
...  

Author(s):  
C. J. Kimmer ◽  
C. K. Harnett

High tensile strength cables, low-resistance motor windings, and shape memory actuators are common examples of technical fibers used in robots and other electromechanical assemblies. Because properties like tensile strength, crystal structure, and polymer alignment depend strongly on processing history, these materials cannot be 3D printed with the same properties they have on the spool. Strings and fibers are inserted in mechanical parts at the end of the manufacturing process for these assemblies. When the fibers take complex paths, the installation is often done by hand. This activity can dominate the process time, increase its human labor and reduce its social sustainability [1]. This paper applies the non-traditional approach of machine embroidery to insert sheets of patterned fibers in layered additive manufacturing processes such as 3D printing and lamination. Fibers are aligned with features in laser-cut or printed parts without the manual labor of hand threading. We demonstrate that water-soluble stabilizer materials originally designed for textiles can hold hard mechanical parts in a machine embroidery hoop with enough strength and rigidity to withstand sewing through pre-existing holes in the part. Alignment to within 250 microns has been demonstrated with a sub-$300 consumer embroidery machine. Case studies in this paper include a cable-driven mechanism, a soft-to-hard electronic connection, and an electromechanical sensor. Process-compatible and commercially available materials that can be embroidered include conductive threads, shrinking threads, water-soluble threads and high tensile strength fibers. The biggest hurdle for a user interested in this automated fiber installation process is linking the existing design file with an embroidery machine file. There is a much larger user base for 2D and 3D computer-assisted design (CAD) software than for expensive and proprietary embroidery digitizing software. We take the route chosen by the laser cutter industry, where the user produces a CAD file in their preferred editor, and makes annotations that communicate where and how densely to stitch. Translation software scans the file for a particular line style and generates stitch coordinates along it. Development is done in Jupyter/iPython notebooks that allow end-users to inspect, understand, and modify the conversion code. The intent is for users of existing planar fabrication technology (whether laser, printed circuit board, or micro/nano) to apply this method to their own CAD files for a versatile and straightforward way to put advanced materials in their devices without adding manual labor. This general approach can solve a class of assembly problems relevant to underactuated tendon-driven robotics and other electromechanical systems, expanding the range of devices that can be put together using automation.


Polymer ◽  
2019 ◽  
Vol 176 ◽  
pp. 283-292 ◽  
Author(s):  
Callie E. Zawaski ◽  
Emily M. Wilts ◽  
Camden A. Chatham ◽  
Andre T. Stevenson ◽  
Allison M. Pekkanen ◽  
...  

Author(s):  
Gurminder Singh ◽  
Jean-Michel Missiaen ◽  
Didier Bouvard ◽  
Jean-Marc Chaix

AbstractIn the present study, an additive manufacturing process of copper using extrusion 3D printing, solvent and thermal debinding, and sintering was explored. Extrusion 3D printing of metal injection moulding (MIM) feedstock was used to fabricate green body samples. The printing process was performed with optimized parameters to achieve high green density and low surface roughness. To remove water-soluble polymer, the green body was immersed in water for solvent debinding. The interconnected voids formed during solvent debinding were favorable for removing the backbone polymer from the brown body during thermal debinding. Thermal debinding was performed up to 500 °C, and ~ 6.5% total weight loss of the green sample was estimated. Finally, sintering of the thermally debinded samples was performed at 950, 1000, 1030, and 1050°C. The highest sintering temperature provided the highest relative density (94.5%) and isotropic shrinkage. Micro-computed tomography (μCT) examination was performed on green samples and sintered samples, and qualitative and quantitative analysis of the porosity confirmed the benefits of optimized printing conditions for the final microstructure. This work opens up the opportunity for 3D printing and sintering to produce pure copper components with complicated shapes and high density, utilizing raw MIM feedstock as the starting material.


Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 474 ◽  
Author(s):  
Brice Le Borgne ◽  
Emmanuel Jacques ◽  
Maxime Harnois

The integration of electronics into the process flow of the additive manufacturing of 3D objects is demonstrated using water soluble films as a temporary flexible substrate. Three process variants are detailed to evaluate their capabilities to meet the additive manufacturing requirements. One of them, called water transfer printing, shows the best ability to fabricate electronics onto 3D additively manufactured objects. Moreover, a curved capacitive touchpad hidden by color films is successfully transferred onto the 3D objects, showing a potential application of this technology to fabricate fully additively manufactured discrete or even hidden electronic devices.


2014 ◽  
Vol 15 (3-4) ◽  
Author(s):  
Xiao-Hua Qin ◽  
Aleksandr Ovsianikov ◽  
Jürgen Stampfl ◽  
Robert Liska

AbstractHydrogels are extensively explored as scaffolding materials for 2D/3D cell culture and tissue engineering. Owing to the substantial complexity of tissues, it is increasingly important to develop 3D biomimetic hydrogels with user-defined architectures and controllable biological functions. To this end, one promising approach is to utilize photolithography-based additive manufacturing technologies (AMTs) in combination with photosensitive hydrogels. We here review recent advances in photolithography-based additive manufacturing of 3D hydrogels for tissue engineering applications. Given the importance of materials selection, we firstly give an overview of water-soluble photoinitiators for single- and two-photon polymerization, photopolymerizable hydrogel precursors and light-triggered chemistries for hydrogel formation. Through the text we discuss the design considerations of hydrogel precursors and synthetic approaches to polymerizable hydrogel precursors of synthetic and natural origins. Next, we shift to how photopolymerizable hydrogels could integrate with photolithography-based AMTs for creating well-defined hydrogel structures. We illustrate the working-principles of both single- and two-photon lithography and case studies of their applications in tissue engineering. In particular, two-photon lithography is highlighted as a powerful tool for 3D functionalization/construction of hydrogel constructs with μm-scale resolution. Within the text we also explain the chemical reactions involved in two-photon-induced biofunctionalization and polymerization. In the end, we summarize the limitations of available hydrogel systems and photolithography-based AMTs as well as a future outlook on potential optimizations.


Author(s):  
J. G. Robertson ◽  
D. F. Parsons

The extraction of lipids from tissues during fixation and embedding for electron microscopy is widely recognized as a source of possible artifact, especially at the membrane level of cell organization. Lipid extraction is also a major disadvantage in electron microscope autoradiography of radioactive lipids, as in studies of the uptake of radioactive fatty acids by intestinal slices. Retention of lipids by fixation with osmium tetroxide is generally limited to glycolipids, phospholipids and highly unsaturated neutral lipids. Saturated neutral lipids and sterols tend to be easily extracted by organic dehydrating reagents prior to embedding. Retention of the more saturated lipids in embedded tissue might be achieved by developing new cross-linking reagents, by the use of highly water soluble embedding materials or by working at very low temperatures.


Author(s):  
J. D. McLean ◽  
S. J. Singer

The successful application of ferritin labeled antibodies (F-A) to ultrathin sections of biological material has been hampered by two main difficulties. Firstly the normally used procedures for the preparation of material for thin sectioning often result in a loss of antigenicity. Secondly the polymers employed for embedding may non-specifically absorb the F-A. Our earlier use of cross-linked polyampholytes as embedding media partially overcame these problems. However the water-soluble monomers used for this method still extract many lipids from the material.


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