scholarly journals Cavity vat photopolymerisation for additive manufacturing of polymer-composite 3D objects

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Joel Bachmann ◽  
Philip Obst ◽  
Lukas Knorr ◽  
Stefan Schmölzer ◽  
Gabriele Fruhmann ◽  
...  
Keyword(s):  
Composite Material ◽  
Additive Manufacturing ◽  
Manufacturing Processes ◽  
Solid Object ◽  
Thermal Curing ◽  
Covalent Bonds ◽  
Liquid Resin ◽  
3D Objects ◽  
Hard Shell ◽  
Dual Curing

AbstractVat photopolymerisation describes resin-based additive manufacturing processes in which ultraviolet light is used to layer-wise solidify liquid resin into a desired 3D shape. If the starting resin is a dual-curing formulation the object is also thermally cured to attain its final properties, obtaining either an elastomer or a thermoset. Here, we introduce cavity vat photopolymerisation, in which one photopolymer resin produces a composite material of an elastomer and thermoset. Cavities of any geometry are purposefully designed in the solid object and then filled with liquid resin during printing due to negative pressure. Thermal curing then solidifies the resin in the cavities into an elastomer, forming a distinct interface held together by strong covalent bonds. Hybrid specimens indicate improved damping, reduced fragmentation upon fracture and increased local elasticity, and we suggest several hard-shell/soft-core applications that might benefit.

scholarly journals A Review of Stereolithography: Processes and Systems

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1138 ◽  
Author(s):  
Jigang Huang ◽  
Qin Qin ◽  
Jie Wang
Keyword(s):  
Additive Manufacturing ◽  
Technological Innovation ◽  
High Accuracy ◽  
Materials Selection ◽  
Liquid Resin ◽  
3D Objects ◽  
The Past ◽  
Selection For ◽  
System Configurations ◽  
Magnetically Assisted

Being the earliest form of additive manufacturing, stereolithography (SLA) fabricates 3D objects by selectively solidifying the liquid resin through a photopolymerization reaction. The ability to fabricate objects with high accuracy as well as a wide variety of materials brings much attention to stereolithography. Since its invention in the 1980s, SLA underwent four generations of major technological innovation over the past 40 years. These innovations have thus resulted in a diversified range of stereolithography systems with dramatically improved resolution, throughput, and materials selection for creating complex 3D objects and devices. In this paper, we review the four generations of stereolithography processes, which are scanning, projection, continuous and volumetric stereolithography. For each generation, representative stereolithography system configurations are also discussed in detail. In addition, other derivative technologies, such as scanning–projection, multi-material, and magnetically assisted stereolithography processes, are also included in this review.

scholarly journals Additive Manufacturing Under Lunar Gravity and Microgravity

2021 ◽  
Vol 33 (2) ◽  
Author(s):  
B. Reitz ◽  
C. Lotz ◽  
N. Gerdes ◽  
S. Linke ◽  
E. Olsen ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Spare Parts ◽  
Manufacturing Processes ◽  
Complex Structures ◽  
Lunar Gravity ◽  
Limited Extent ◽  
Test Environment ◽  
Manufacturing Tests ◽  
Laser Experiments ◽  
Materials Used

AbstractMankind is setting to colonize space, for which the manufacturing of habitats, tools, spare parts and other infrastructure is required. Commercial manufacturing processes are already well engineered under standard conditions on Earth, which means under Earth’s gravity and atmosphere. Based on the literature review, additive manufacturing under lunar and other space gravitational conditions have only been researched to a very limited extent. Especially, additive manufacturing offers many advantages, as it can produce complex structures while saving resources. The materials used do not have to be taken along on the mission, they can even be mined and processed on-site. The Einstein-Elevator offers a unique test environment for experiments under different gravitational conditions. Laser experiments on selectively melting regolith simulant are successfully conducted under lunar gravity and microgravity. The created samples are characterized in terms of their geometry, mass and porosity. These experiments are the first additive manufacturing tests under lunar gravity worldwide.

scholarly journals Variable low-density polylactic acid and microsphere composite material for additive manufacturing

2021 ◽  
pp. 101925
Author(s):  
Henrik Andersson ◽  
Jonas Örtegren ◽  
Renyun Zhang ◽  
Markus Grauers ◽  
Håkan Olin
Keyword(s):  
Composite Material ◽  
Additive Manufacturing ◽  
Polylactic Acid ◽  
Low Density

scholarly journals An Additively Manufactured Titanium Alloy in the Focus of Metallography

2021 ◽  
Vol 58 (1) ◽  
pp. 4-31
Author(s):  
C. Fleißner-Rieger ◽  
T. Pogrielz ◽  
D. Obersteiner ◽  
T. Pfeifer ◽  
H. Clemens ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Microstructural Analysis ◽  
Microstructural Characterization ◽  
Melting Process ◽  
Manufacturing Processes ◽  
Ingot Metallurgy ◽  
Lightweight Structures ◽  
Metallographic Preparation ◽  
Fine Structures ◽  
Specific Material

Abstract Additive manufacturing processes allow the production of geometrically complex lightweight structures with specific material properties. However, by contrast with ingot metallurgy methods, the manufacture of components using this process also brings about some challenges. In the field of microstructural characterization, where mostly very fine structures are analyzed, it is thus indispensable to optimize the classic sample preparation process and to furthermore implement additional preparation steps. This work focuses on the metallography of additively manufactured Ti‑6Al‑4V components produced in a selective laser melting process. It offers a guideline for the metallographic preparation along the process chain of additive manufacturing from the metal powder characterization to the macro- and microstructural analysis of the laser melted sample. Apart from developing preparation parameters, selected etching methods were examined with regard to their practicality.

Enabler für die personalisierte Produktion*/Automated additive manufacturing processes as enabler for personalized production – A sample application for tailor-made products

2019 ◽  
Vol 109 (03) ◽  
pp. 179-183
Author(s):  
J. Fischer ◽  
P. Springer ◽  
S. Fulga-Beising ◽  
K. Abu El-Qomsan
Keyword(s):  
Data Analysis ◽  
Additive Manufacturing ◽  
Manufacturing System ◽  
Personal Data ◽  
Industrie 4.0 ◽  
Manufacturing Processes ◽  
Automated Production ◽  
Sample Application

Das Fraunhofer IPA forscht an Workflows und Methoden für die Herstellung personalisierter Produkte von der Erfassung persönlicher Daten über die Analyse und Modellierung bis hin zur flexiblen, automatisierten Fertigung der Produkte. Der Beitrag beschreibt einen beispielhaften Anwendungsfall: die Herstellung einer personalisierten Brille. Für die nötige Flexibilität in der Fertigung wurde ein vollständig automatisiertes additives Fertigungssystem entwickelt, das im Applikationszentrum Industrie 4.0 des Fraunhofer IPA und des Instituts für Industrielle Fertigung und Fabrikbetrieb IFF der Universität Stuttgart integriert ist.   Fraunhofer IPA examines workflows and methods for the production of personalized products from the acquisition of personal data, analysis and modelling to the flexible, automated production of the products. This paper exemplifies an application using the production of personalized glasses. For this purpose, a fully automated additive manufacturing system was developed to provide the necessary flexibility in manufacturing.

Einbringen von Gewinden in SLM-Bauteile*/Insertion of threads into SLM components – Reliable strategy for inserting threads into additively manufactured components

2019 ◽  
Vol 109 (01-02) ◽  
pp. 24-29
Author(s):  
E. Abele ◽  
T. Scherer ◽  
F. Geßner ◽  
M. Weigold
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Downstream Processing ◽  
Manufacturing Processes ◽  
Laser Melting ◽  
Manufacturing Costs ◽  
Process Reliability ◽  
High Degree ◽  
Design Freedom ◽  
Processing Steps

Additive Fertigungsverfahren zeichnen sich durch große Gestaltungsfreiheit aus, welche die Herstellung komplexer Bauteile ermöglicht. Angesichts hoher Fertigungskosten ist die Prozesssicherheit nachgeordneter Bearbeitungsschritte (wie zum Beispiel die Gewindefertigung) von großer Bedeutung. Der Artikel stellt die Ergebnisse einer Untersuchungsreihe vor, die unterschiedliche Ansätze der Gewindefertigung in Bauteilen aus Stahl behandelt, die mittels Selektivem Laserschmelzverfahren gefertigt wurden.   Additive manufacturing processes are characterized by a high degree of design freedom to enablet the production of complex components. To reduce manufacturing costs, the process reliability of downstream processing steps (e. g. thread production) is of great importance. This article presents the results of a series of investigations dealing with different approaches to thread production in steel components manufactured by selective laser melting

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