Microsurgical Devices by Pop-Up Book MEMS

2013 ◽  
Author(s):  
Joshua B. Gafford ◽  
Samuel B. Kesner ◽  
Robert J. Wood ◽  
Conor J. Walsh
Keyword(s):  
Lap Joints ◽  
Small Scale ◽  
Flexible Hinge ◽  
Final Weight ◽  
Out Of Plane ◽  
Return Spring ◽  
Torsional Loads ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing ◽  
Electrical Components

The small scale of microsurgery poses significant challenges for developing robust and dexterous tools to grip, cut, and join sub-millimeter structures such as vessels and nerves. The main limitation is that traditional manufacturing techniques are not optimized to create smart, articulating structures in the 0.1–10 mm scale. Pop-up book MEMS is a new fabrication technology that promises to overcome this challenge and enable the monolithic fabrication of complex, articulated structures with an extensive catalog of materials, embedded electrical components, and automated assembly with feature sizes down to 20 microns. In this paper, we demonstrate a proof-of-concept microsurgical gripper and evaluate its performance at the component and device level to characterize its strength and robustness. 1-DOF Flexible hinge joints that constrain motion and allow for out-of-plane actuation were found to resist torsional loads of 22.8±2.15 N·mm per mm of hinge width. Adhesive lap joints that join individual layers in the laminate structure demonstrated a shear strength of 26.8±0.53 N/mm2. The laminate structures were also shown to resist peel loads of 0.72±0.10 N/mm2. Various flexible hinge and adhesive lap components were then designed into an 11-layered structure which ‘pops up’ to realize an articulating microsurgical gripper that includes a cable-driven mechanism for gripping actuation and a flexural return spring to passively open the gripper. The gripper prototype, with final weight of 200 mg, overall footprint of 18 mm by 7.5 mm, and features as small as 200 microns, is able to deftly manipulate objects 100 times is own weight at the required scale, thus demonstrating its potential for use in microsurgery.

Build Direction Effects on Additively Manufactured Channels

2015 ◽  
Author(s):  
Jacob C. Snyder ◽  
Curtis K. Stimpson ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Small Scale ◽  
Turbine Cooling ◽  
Gas Turbine Cooling ◽  
Gas Turbine Heat Transfer ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing

With the advances of Direct Metal Laser Sintering (DMLS), also generically referred to as additive manufacturing, novel geometric features of internal channels for gas turbine cooling can be achieved beyond those features using traditional manufacturing techniques. There are many variables, however, in the DMLS process that affect the final quality of the part. Of most interest to gas turbine heat transfer designers are the roughness levels and tolerance levels that can be held for the internal channels. This study investigates the effect of DMLS build direction and channel shape on the pressure loss and heat transfer measurements of small scale channels. Results indicate that differences in pressure loss occur between the test cases with differing channel shapes and build directions, while little change is measured in heat transfer performance.

Build Direction Effects on Additively Manufactured Channels

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Jacob C. Snyder ◽  
Curtis K. Stimpson ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Small Scale ◽  
Turbine Cooling ◽  
Gas Turbine Cooling ◽  
Gas Turbine Heat Transfer ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing

With the advance of direct metal laser sintering (DMLS), also generically referred to as additive manufacturing (AM), novel geometric features of internal channels for gas turbine cooling can be achieved beyond those features using traditional manufacturing techniques. There are many variables, however, in the DMLS process that affect the final quality of the part. Of most interest to gas turbine heat transfer designers are the roughness levels and tolerance levels that can be held for the internal channels. This study investigates the effect of DMLS build direction and channel shape on the pressure loss and heat transfer measurements of small-scale channels. Results indicate that differences in pressure loss occur between the test cases with differing channel shapes and build directions, while little change is measured in heat transfer performance.

scholarly journals 3D Printing of Mini Tablets for Pediatric Use

2021 ◽  
Vol 14 (2) ◽  
pp. 143
Author(s):  
Julius Krause ◽  
Laura Müller ◽  
Dorota Sarwinska ◽  
Anne Seidlitz ◽  
Malgorzata Sznitowska ◽  
...  
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Dosage Forms ◽  
Small Scale ◽  
Fused Deposition ◽  
On Demand ◽  
Pediatric Diseases ◽  
Deposition Modeling ◽  
Manufacturing Techniques ◽  
Pediatric Use

In the treatment of pediatric diseases, suitable dosages and dosage forms are often not available for an adequate therapy. The use of innovative additive manufacturing techniques offers the possibility of producing pediatric dosage forms. In this study, the production of mini tablets using fused deposition modeling (FDM)-based 3D printing was investigated. Two pediatric drugs, caffeine and propranolol hydrochloride, were successfully processed into filaments using hyprolose and hypromellose as polymers. Subsequently, mini tablets with diameters between 1.5 and 4.0 mm were printed and characterized using optical and thermal analysis methods. By varying the number of mini tablets applied and by varying the diameter, we were able to achieve different release behaviors. This work highlights the potential value of FDM 3D printing for the on-demand production of patient individualized, small-scale batches of pediatric dosage forms.

Influence of Interference and Clamping on Fretting Fatigue in Single Rivet-Row Lap Joints

2000 ◽  
Vol 123 (4) ◽  
pp. 686-698 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Crack Initiation ◽  
Three Dimensional ◽  
Fretting Fatigue ◽  
Cyclic Stress ◽  
Lap Joints ◽  
Element Analysis ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Fretting Damage

Primary fretting fatigue variables such as contact pressure, slip amplitude and bulk cyclic stresses, at and near the contact interface between the rivet shank and panel hole in a single rivet-row, 7075-T6 aluminum alloy lap joint are presented. Three-dimensional finite element analysis is applied to evaluate these and the effects of interference and clamping stresses on the values of the primary variables and other overall measures of fretting damage. Two rivet geometries, non-countersunk and countersunk, are considered. Comparison with previous evaluations of the fretting conditions in similar but two-dimensional connections indicates that out-of-plane movements and attending effects can have a significant impact on the fatigue life of riveted connections. Variations of the cyclic stress range and other proponents of crack initiation are found to peak at distinct locations along the hole-shank interface, making it possible to predict crack initiation locations and design for extended life.

Directly bonded single lap joints of SiCp/AA2124 composite with glass fiber-reinforced polypropylene: Hole drilling effects on lap shear strength and out-of-plane impact response

2021 ◽  
pp. 002199832110316
Author(s):  
Nahit Öztoprak
Keyword(s):  
Glass Fiber ◽  
Matrix Composite ◽  
Lap Joints ◽  
Hole Drilling ◽  
Fiber Reinforced ◽  
Single Lap Joints ◽  
Lap Shear ◽  
Glass Fiber Reinforced ◽  
Out Of Plane ◽  
The Impact

Joining dissimilar materials to achieve lightweight design and energy efficiency has been increasingly popular. A joint formed by components of particle-reinforced metal and polymer matrix composite combines the merits of both materials. This paper is mainly focused on the research of the tensile lap shear and impact behavior of the dissimilar single-lap joints (SLJs) between SiCp/AA2124 composite and glass fiber-reinforced polypropylene (PP). The effects of out-of-plane loading applied from different surfaces of SLJs on impact responses are evaluated. Hot pressing technique is introduced to manufacture metal/polymer assembly without using any adhesive. The hole drilling effect is investigated with the idea that it may provide weight reduction and also increase the strength of the dissimilar SLJs. The results indicate that the dissimilar SLJs show more Charpy impact strength when the impact is performed on the metal-matrix composite (MMC). Mechanical properties of SLJs are adversely affected by a drilled hole in the MMC adherend.

scholarly journals 3D printing technologies for creating models and nozzles in an aerodynamic shock tunnel experiment

2021 ◽  
Vol 2103 (1) ◽  
pp. 012033
Author(s):  
M A Kotov ◽  
N A Monakhov ◽  
S A Poniaev ◽  
P A Popov ◽  
K V Tverdokhlebov
Keyword(s):  
3D Printing ◽  
High Speed ◽  
Additive Technologies ◽  
Structure And Properties ◽  
Dynamic Experiment ◽  
Advantages And Disadvantages ◽  
Nozzle Block ◽  
Rapid Prototyping And Manufacturing ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing

Abstract The features of 3D printing method for rapid prototyping and manufacturing of models for a pulsed high-speed gas-dynamic experiment are considered. Modern additive technologies allow the production of models. The basic properties of the materials and the advantages of 3D printing methods are described. The structure and properties of the obtained models can be unattainable using traditional manufacturing techniques. The design of the wind tunnel nozzle block is considered, which provides for the production of profiled contours using 3D printing. The advantages and disadvantages of use of such units on the shock tube are considered.

Comparing Environmental Impacts of Additive Manufacturing vs. Investment Casting for the Production of a Shroud for Gas Turbine

2021 ◽  
Author(s):  
Angela Serra ◽  
Martina Malarco ◽  
Alessandro Musacchio ◽  
Giulio Buia ◽  
Pietro Bartocci ◽  
...  
Keyword(s):  
Life Cycle ◽  
Additive Manufacturing ◽  
Environmental Impact ◽  
Investment Casting ◽  
Gas Turbines ◽  
Raw Materials ◽  
Base Material ◽  
Small Scale ◽  
Atomization Process ◽  
Traditional Manufacturing

Abstract Additive manufacturing (AM hereinafter) is revolutionizing prototyping production and even small-scale manufacturing. Usually it is assumed that AM has lower environmental impact, compared to traditional manufacturing processes, but there have been no comprehensive environmental life-cycle assessment studies confirming this, especially for the gas turbines (GT hereinafter) and turbomachinery sector. In this study the core processes performed at Baker Hughes site in Florence are considered, together with the powder production via atomization process to describe the overall environmental impact of a GT shroud produced through additive manufacturing and comparing it with traditional investment casting production process. Particular attention is given to materials production and logistics. The full component life cycle starts from the extraction of raw materials during mining, their fusion and, as said, the atomization process, the powders are transported to the gas turbines production site where they are used as base material in additive manufacturing, also machining and finishing processes are analyzed as they differ for a component produced by AM respect to one produced by traditional investment casting. From the analysis of the data obtained, it emerges that the AM process has better performances in terms of sustainability than the Investment casting (IC hereinafter), highlighted above all by a decrease in greenhouse gas emissions (GHG hereinafter) of over 40%.

Computational Study of Reinforcement Mechanisms of Cuttlefish Bone Inspired Structure for 3D Printing

2021 ◽  
Author(s):  
Brandon Bethers ◽  
Yang Yang
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Computational Study ◽  
High Energy ◽  
Simulation Software ◽  
Support Structures ◽  
Common Support ◽  
Potential Applications ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing

Abstract Cuttlebone, the internal shell structure of a cuttlefish, presents a unique labyrinthian wall-septa design that promotes high energy absorption, porosity, and damage tolerance. This structure offers us an inspiration for the design of lightweight and strong structures for potential applications in mechanical, aerospace and biomedical engineering. However, the complexity of the cuttlebones structural design makes its fabrication by traditional manufacturing techniques not feasible. The advances in additive manufacturing (3D printing) make highly complex structures like cuttlebone possible to manufacture. In this work, the authors sought to establish comparative data between cuttlebone structures and some common support structures used in additive manufacturing. The structures compared to cuttlebone in this work include the cubic, honeycomb and triangular support structures. This was accomplished by using CAD modeling and simulation software. This study found that the cuttlefish structures had higher average stress values than the others but similar average strain values. This leads to a higher modulus of elasticity for the cuttlebone structures. The data suggests that further research into cuttlebone structures could produce future designs that improve upon the current well-established additive manufacturing support structures. Further study will be performed for the 3D printing of cuttlebone inspired structures by using various types of materials, such as soft and rigid polymers, functional ceramics, composites, and metals.

scholarly journals Hybrid additive manufacturing of steels and alloys

2020 ◽  
Vol 7 ◽  
pp. 6
Author(s):  
Vladimir V. Popov ◽  
Alexander Fleisher
Keyword(s):  
Additive Manufacturing ◽  
Energy Deposition ◽  
Modern Trend ◽  
Production Chain ◽  
Direct Energy Deposition ◽  
Powder Bed ◽  
Direct Energy ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing

Hybrid additive manufacturing is a relatively modern trend in the integration of different additive manufacturing techniques in the traditional manufacturing production chain. Here the AM-technique is used for producing a part on another substrate part, that is manufactured by traditional manufacturing like casting or milling. Such beneficial combination of additive and traditional manufacturing helps to overcome well-known issues, like limited maximum build size, low production rate, insufficient accuracy, and surface roughness. The current paper is devoted to the classification of different approaches in the hybrid additive manufacturing of steel components. Additional discussion is related to the benefits of Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) approaches for hybrid additive manufacturing of steel components.

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