Nanoparticle Additive Manufacturing of Ni-H13 Steel Injection Molds

2004 ◽  
Vol 126 (3) ◽  
pp. 637-639 ◽  
Author(s):  
Rajeev Nair, ◽  
Wenping Jiang, and ◽  
Pal Molian
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Solid Freeform Fabrication ◽  
Fabrication Process ◽  
Ni Nanoparticles ◽  
H13 Steel ◽  
Freeform Fabrication

This paper reports a novel solid freeform fabrication process, Nanoparticle Additive Manufacturing (NAM), for dispersing nanoparticles into molten matrix for improved mechanical properties. In addition, it also presents the characterization of microstructure and hardness of the fabricated Ni-nanoparticles dispersed H13 steel gear-shaped molds.

Cells (MC3T3-E1)-Laden Alginate Scaffolds Fabricated by a Modified Solid-Freeform Fabrication Process Supplemented with an Aerosol Spraying

2012 ◽  
Vol 13 (9) ◽  
pp. 2997-3003 ◽  
Author(s):  
SeungHyun Ahn ◽  
HyeongJin Lee ◽  
Lawrence J. Bonassar ◽  
GeunHyung Kim
Keyword(s):  
Solid Freeform Fabrication ◽  
Fabrication Process ◽  
Freeform Fabrication

Influence of Liquid Phase Migration on Intermittent Extrusion of Aqueous Al2O3 Paste

2011 ◽  
Vol 189-193 ◽  
pp. 177-180
Author(s):  
Hong Jun Liu
Keyword(s):  
Liquid Phase ◽  
Solid Freeform Fabrication ◽  
Extrusion Process ◽  
Fabrication Process ◽  
Extrusion Pressure ◽  
Strong Impact ◽  
Fabrication Method ◽  
Liquid Content ◽  
Freeform Fabrication ◽  
Paste Extrusion

Extrusion Freeform Fabrication Process (EFF) is an environmentally friendly solid freeform fabrication method that uses aqueous pastes to fabricate ceramic-based components. The Liquid Phase Migration (LPM) causes variation in liquid content and consequently problems in the paste extrusion. To get uniform ceramics parts with desired composition, the LPM should be avoided in extrusion process. This paper investigated the influence of LPM on extrusion process for aqueous alumina paste in EFF process. It shows that the liquid phase migration occurs in Freeform Extrusion Fabrication process and has a strong impact on extrusion pressure. The LPM can be characterized by the extrusion pressure-ram displacement profiles. The liquid phase migration becomes more serious in intermittent extrusion at low ram velocity.

Characterization of Permeability for Solid Freeform Fabricated Porous Structures

1999 ◽  
Author(s):  
Merve Erdal ◽  
Levent Ertoz ◽  
Selçuk Güçeri
Keyword(s):  
Solid Freeform Fabrication ◽  
Pore Geometry ◽  
Fluid Viscosity ◽  
Porous Structures ◽  
Permeability Measurement ◽  
Porous Flow ◽  
Freeform Fabrication ◽  
Fused Deposition ◽  
Order Of Magnitude

Abstract Fused deposition based solid freeform fabrication technique allows manufacturing of potential functional preforms for subsequent Resin Transfer Molding. In this study, the transport property (permeability) of solid freeform fabricated porous preform geometries are investigated. Specifically the effect of pore geometry and network on the permeability is sought. Wet (saturated) permeability experiments were performed for various pore geometries with different viscosity liquids. For all fluids and preform structures investigated in this study, the porous flow exhibited Darcian behavior. The permeability is affected by changes in order of magnitude of fluid viscosity, the effect considerably significant in low porosity preforms. Current work concentrates on dry permeability measurement and development of numerical permeability models for ordered pore geometries (as produced through SFF) that will be compared with experimental results.

Design and characterization of PDO biodegradable intravascular stents

2016 ◽  
Vol 87 (16) ◽  
pp. 1968-1976 ◽  
Author(s):  
Cong-er Wang ◽  
Pei-hua Zhang
Keyword(s):  
Mechanical Properties ◽  
Recovery Rate ◽  
Degradation Process ◽  
Radial Force ◽  
Fabrication Process ◽  
International Standards ◽  
Intravascular Stents ◽  
Shortening Rate ◽  
Degradation Properties

Two novel biodegradable intravascular stents (BIS) with different structures are introduced. Braiding-structural BIS and Z-structural BIS were fabricated from polydioxanone (PDO) monofilament by a hand-braiding method with a perforated mold, imitating commercial stents that have been used clinically. The fabrication process of these two BIS is described and stent parameters, mechanical properties, and degradation properties are reported. The findings reveal that Z-structural BIS have higher porosity, smaller longitudinal shortening rate, and higher radial force and recovery rate compared with the braiding-structural stent. During the degradation process, braiding-structural BIS maintained their mechanical properties higher than international standards for 12 weeks, while Z-structural stents maintained them for 16 weeks.

Effect of Preheating on the Delamination and Crack Formation in Laser Solid Freeform Fabrication Process

2008 ◽  
Author(s):  
Masoud Alimardani ◽  
Ehsan Toyserkani ◽  
Jan Paul Huissoon
Keyword(s):  
Thermal Stresses ◽  
Crack Formation ◽  
Solid Freeform Fabrication ◽  
Fabrication Process ◽  
Experimental Results ◽  
Stress Fields ◽  
Thin Wall ◽  
Freeform Fabrication ◽  
Micro Cracks ◽  
Laser Solid Freeform Fabrication

This paper presents a numerical-experimental investigation on the effects of preheating the substrate on the potential delamination and crack formation across the parts fabricated using the Laser Solid Freeform Fabrication (LSFF) process. For this purpose, the temperature distributions and stress fields induced during the multilayer LSFF process, and their correlation with the delamination and crack formation are studied throughout the numerical analysis and the experimental fabrication of a four-layer thin wall of SS304L. A 3D time-dependent numerical approach is used to simulate the LSFF process, and also interpret the experimental results in terms of the temperature distribution and the thermal stress fields. The numerical results show that by preheating the substrate prior to the fabrication process, the thermal stresses throughout the process domain substantially reduce. Accordingly, this can result in the reduction of potential micro-cracks formation across the fabricated part. Preheating also decreases the transient time for the development of a proper melt pool which is an important factor to prevent poor bonding between deposited layers. The experimental results are used to verify the numerical findings as well as the feasibility of preheating on the reduction of the micro-cracks formed throughout the fabrication process.

Preparation and characterization of hydroxyapatite suspensions for solid freeform fabrication

2002 ◽  
Vol 28 (3) ◽  
pp. 299-302 ◽  
Author(s):  
Jiemo Tian ◽  
Yong Zhang ◽  
Xinmin Guo ◽  
Limin Dong
Keyword(s):  
Solid Freeform Fabrication ◽  
Freeform Fabrication

Novel Highly Potential Initiators for the Two-Photon-Induced Photopolymerization Process

2009 ◽  
Vol 1179 ◽  
Author(s):  
Niklas Pucher ◽  
Valentin Satzinger ◽  
Arnulf Rosspeintner ◽  
Georg Gescheidt ◽  
Volker Schmidt ◽  
...  
Keyword(s):  
Solid Freeform Fabrication ◽  
Photophysical Properties ◽  
Fabrication Process ◽  
Freeform Fabrication ◽  
Structure Activity Relationships ◽  
Two Photon ◽  
Triple Bonds ◽  
Processing Window ◽  
Structure Activity ◽  
Donor And Acceptor

AbstractThe development of new optimized photoinitiators for the two-photon induced photopolymerization (TPIP) is essential in order to obtain high resolutions in this solid freeform fabrication process. Herein, we present the syntheses and characterizations of a series of efficient photoinitiators, comprising of a cross conjugated D-π-A-π-D system. The different donor- and acceptor functionalities of the investigated photoinitiators as well as the synthesis of targeted derivatives containing double and triple bonds in the conjugated backbone allowed the evaluation of structure-activity relationships. The basic photophysical properties as well as the activity and ideal processing window under TPIP conditions were investigated for each initiator and compared with typical commercially available one-photon initiator and with two highly potential initiators well known from literature. These tests figured out that the new chromophores are highly potential even at concentrations down to 0.05 wt%.

Bio-Inspired Fabrication of Polymer Composite Scaffolds with Chitosan Network inside the Pore Channels

2011 ◽  
Vol 140 ◽  
pp. 38-42 ◽  
Author(s):  
Bo Li ◽  
Li Hua Li ◽  
Chang Ren Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Solid Freeform Fabrication ◽  
Environmental Scanning Electron Microscopy ◽  
Osteoblastic Cells ◽  
Environmental Scanning ◽  
Composite Scaffolds ◽  
Freeform Fabrication ◽  
Fibre Network ◽  
Scanning Electron

Solid freeform fabrication, known as rapid prototyping (RP) technology allows in designing the scaffold with pre-defined and controlled external and internal architecture.In this study we produce scaffolds with network of chitosan fibrils that mimic the extracellular matrix produced by the cells. These network scaffolds also consisting of nanoparticles of hydroxyapatite (HA) for stabilisation of scaffolds are characterised by environmental scanning electron microscopy and mechanical properties. ESEM showed that the scaffolds possess macropore (300µm), micropore and fibre network structure. The compressive strength and elastic modulus (E) for the scaffolds are 0.54± 0.02 MPa and 6.13± 0.60 MPa, respectively, which are increasing obviously. The biocompatibility of the woodpile-network scaffolds was investigated with osteoblastic cells. The result showed the distribution and proliferation of osteoblast orients along the chtosan fibre network, preferentially. After 4 weeks of culture, macropore channels are covered by cells in large part,while the areas without chitosan fibre network are covered rarely. The properties of these scaffolds indicate that they can be used for bone tissue engineering applications.

scholarly journals Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Gianpaolo Savio ◽  
Stefano Rosso ◽  
Roberto Meneghello ◽  
Gianmaria Concheri
Keyword(s):  
Tissue Engineering ◽  
Additive Manufacturing ◽  
Geometric Modeling ◽  
Solid Freeform Fabrication ◽  
Cellular Materials ◽  
Point Of View ◽  
Porous Scaffolds ◽  
Freeform Fabrication ◽  
Geometric Point ◽  
Manufacturing Technologies

Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed.

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