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%.

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.

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.

Development of an Indirect Solid Freeform Fabrication Process Based on Stereolithography and Gelcasting for Ceramic Casting Molds

2011 ◽  
Vol 189-193 ◽  
pp. 2581-2585
Author(s):  
Hai Hua Wu ◽  
Zi Fan Fang
Keyword(s):  
Freeze Drying ◽  
Solid Freeform Fabrication ◽  
Fabrication Process ◽  
Green Body ◽  
Casting Mold ◽  
Freeform Fabrication ◽  
Ceramic Slurry ◽  
Ceramic Casting

In this paper, an indirect solid freeform fabrication (ISFF) process was developed to rapidly fabricate ceramic casting molds by combining stereolithography with gelcasting technology. To realize this method, the stereolithography apparatus was used to fabricate a resin mold, and then aqueous ceramic slurry was cast into the resin mold and in situ polymerized to form a wet green body of ceramic casting mold. Freeze drying, pyrolyzing and sintering completed the manufacturing route. Finally, the ceramic casting mold with complex ceramic cores was obtained, and a car radiator with deep grooves was produced to verify the validity and feasibility of the method.

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