Materials Properties and Manufacturing Processes of Nitinol Endovascular Devices

2020 ◽  
pp. 59-79
Author(s):  
Moataz Elsisy ◽  
Youngjae Chun
Keyword(s):  
Manufacturing Processes ◽  
Materials Properties ◽  
Endovascular Devices

An Innovative Method to Construct Silicone Cerebrovascular Replicas

2008 ◽  
Author(s):  
Juyu Chueh ◽  
Ajay K. Wakhloo ◽  
Matthew J. Gounis
Keyword(s):  
Three Dimensional ◽  
Manufacturing Processes ◽  
3D Printer ◽  
Rotational Angiography ◽  
Imaging Data ◽  
Resonance Imaging ◽  
Vascular Lumen ◽  
Innovative Method ◽  
Magnetic Resonance Imaging Mri ◽  
Endovascular Devices

Our objective is to create cerebrovascular replicas that offer detailed geometry from clinical imaging data and have versatile applications such as testing new endovascular devices. To facilitate optical observation, simulate physiological environment and obtain reliable data, the replica is designed to be transparent and elastic with uniform thickness and good compatibility with imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI) and three-dimensional rotational angiography (3DRA). Several different manufacturing processes have been demonstrated in previous studies [1,2]. The physical 3D vasculature models were first obtained either by injecting methylmethacrylate into the human specimens to get vascular lumen casts of the part of interest or sending data derived from images generated from the imaging facilities to 3D printer for rapid prototyping. Different methods including repeated painting, dip-spin processing, and lost-wax technique were then applied to the casts to form the elastomeric replicas.

scholarly journals Variations in the Surface Integrity of Ti-6Al-4V by Combinations of Additive and Subtractive Manufacturing Processes

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1825 ◽  
Author(s):  
Roland Bejjani ◽  
Erik Bamford ◽  
Stefan Cedergren ◽  
Andreas Archenti ◽  
Amir Rashid
Keyword(s):  
Surface Integrity ◽  
Research Work ◽  
Manufacturing Industries ◽  
Manufacturing Processes ◽  
Materials Properties ◽  
Aerospace Sector ◽  
Different Types ◽  
Subtractive Manufacturing ◽  
Manufacturing Methods ◽  
Am Processes

Additive manufacturing (AM) has recently been accorded considerable interest by manufacturers. Many manufacturing industries, amongst others in the aerospace sector, are already using AM parts or are investing in such manufacturing methods. Important material properties, such as microstructures, residual stress, and surface topography, can be affected by AM processes. In addition, a subtractive manufacturing (SM) process, such as machining, is required for finishing certain parts when accurate tolerances are required. This finish machining will subsequently affect the surface integrity and topography of the material. In this research work, we focused on the surface integrity of Ti-6Al-4V parts manufactured using three different types of AM and finished using an SM step. The aim of this study was to gain an understanding on how each process affects the resulting surface integrity of the material. It was found that each AM process affects the materials’ properties differently and that clear differences exist compared to a reference material manufactured using conventional methods. The newly generated surface was investigated after the SM step and each combination of AM/SM resulted in differences in surface integrity. It was found that different AM processes result in different microstructures which in turn affect surface integrity after the SM process.

Applications of Transmission Electron Microscopy in the Characterization of Metal Machinability

1968 ◽  
Vol 26 ◽  
pp. 442-443 ◽  
Author(s):  
L.E. Murr ◽  
A.B. Draper
Keyword(s):  
Electron Microscopy ◽  
State Physics ◽  
Test Material ◽  
Milling Machine ◽  
Rotary Table ◽  
Solid State Physics ◽  
Materials Properties ◽  
Transmission Electron ◽  
Selection Of

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.

Impact of fiber structure on edge-wicking of highly-sized paperboard

TAPPI Journal ◽  
2018 ◽  
Vol 17 (08) ◽  
pp. 437-443
Author(s):  
Lebo Xu ◽  
Jeremy Meyers ◽  
Peter Hart
Keyword(s):  
Fiber Surface ◽  
Manufacturing Processes ◽  
Paper Machine ◽  
Liquid Penetration ◽  
Fiber Structure ◽  
Cut Edge ◽  
Local Fiber

Coffee edge-wicking testing was conducted on two groups of highly-sized paperboard manufactured at two mills with similar manufacturing processes, but with vastly different local fiber sources. Although the Hercules size test (HST) indicated similar internal size levels between the two types of board, the edge-wicking behavior was noticeably different. Analysis of fiber structure revealed that the board with more edge-wicking had fibers with thicker fiber walls, which kept the fiber lumen more open after pressing and drying on a paper machine. It was demonstrated that liquid penetration through voids between fibers in highly-sized paperboard was limited, because the fiber surface was well protected by the presence of sufficient sizing agent. Nevertheless, freshly exposed fiber walls and lumens at the cut edge of the sheet were not protected by sizing material, which facilitated edge-wicking. The correlation between fiber structure and edge-wicking behavior was highlighted in this work to inspire development of novel sizing strategies that protect the freshly cut edge of the sheet from edge-wicking.

Re-Programming Hydrogel Properties using a Fuel-driven Reaction Cycle

2019 ◽  
Author(s):  
Nishant Singh ◽  
Bruno Lainer ◽  
Georges Formon ◽  
Serena De Piccoli ◽  
Thomas Hermans
Keyword(s):  
Methionine Oxidation ◽  
Guanosine Triphosphate ◽  
Control Reaction ◽  
Reaction Cycle ◽  
Materials Properties ◽  
Assembly Kinetics ◽  
Control Assembly ◽  
Indispensable Tool ◽  
Reaction Cycles ◽  
Non Equilibrium

Nature uses catalysis as an indispensable tool to control assembly and reaction cycles in vital non-equilibrium supramolecular processes. For instance, enzymatic methionine oxidation regulates actin (dis)assembly, and catalytic guanosine triphosphate hydrolysis is found in tubulin (dis)assembly. Here we present a completely artificial reaction cycle which is driven by a chemical fuel that is catalytically obtained from a ‘pre-fuel’. The reaction cycle controls the disassembly and re-assembly of a hydrogel, where the rate of pre-fuel turnover dictates the morphology as well as the mechanical properties. By adding additional fresh aliquots of fuel and removing waste, the hydrogels can be re-programmed time after time. Overall, we show how catalysis can control fuel generation to control reaction / assembly kinetics and materials properties in life-like non-equilibrium systems.

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