Multiphysics Challenges for Controlling Layered Manufacturing Processes Targeting Thermomechanical Performance

2014 ◽  
Author(s):  
John G. Michopoulos ◽  
Samuel Lambrakos ◽  
Athanasios Iliopoulos
Keyword(s):  
Additive Manufacturing ◽  
Process Control ◽  
Modeling And Simulation ◽  
Functional Performance ◽  
Modeling Processes ◽  
Layered Manufacturing ◽  
Simple Problem ◽  
Manufacturing Processes ◽  
On Demand ◽  
Mass And Heat Transfer

In an effort to enable on-demand process control of additive manufacturing processes for achieving component performance by design from a modeling and simulation perspective and context, we introduce a method for identifying relevant modeling and simulation challenges for the purpose of motivating research that addresses this problem. We first present the abstraction of the multiscale modeling processes connecting process control with functional performance both from the forward and inverse perspectives. We subsequently introduce a brief ontology describing the ordering of dependency and membership of all components of a model in order to isolate the potential areas where challenges can be exposed. We subsequently select some features that are usually ignored by the community during modeling. In particular, we demonstrate using a simple problem of mass and heat transfer, which is relevant to layered additive manufacturing, the implications and dangers related to ignoring process dependence on deposition path history.

Towards a Unified In-Process Geometrical Model for Multiple Machining and Layered Manufacturing

2005 ◽  
Author(s):  
Peiling Liu ◽  
Cheng-Feng Zhu ◽  
Bin Song ◽  
Wen Feng Lu ◽  
YiQiang Lu ◽  
...  
Keyword(s):  
Modeling And Simulation ◽  
Data Exchange ◽  
Geometrical Model ◽  
Layered Manufacturing ◽  
Manufacturing Processes ◽  
Simulation Tools ◽  
Geometry Model ◽  
Critical Issues ◽  
Modern Manufacturing ◽  
Traditional Manufacturing

There are many fabrication processes in modern manufacturing, but current modeling and simulation tools only simulate a few unit processes based on different geometry models. To overcome the data exchange problem between different models, this paper studies various in-process geometry models together with their working systems / prototypes for traditional manufacturing processes. Novel hybrid multiple-machining and layered manufacturing processes are presented to identify critical issues. Working towards a vision of pervasive modeling and simulation, a unified Voxel-based in-process geometry model for multiple-machining and layered manufacturing simulations is proposed and discussed.

A Model Predictive Repetitive Process Control Formulation for Additive Manufacturing Processes

2015 ◽  
Author(s):  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers
Keyword(s):  
Additive Manufacturing ◽  
Process Control ◽  
Predictive Control ◽  
Reference Signal ◽  
Deposition Process ◽  
Open Loop ◽  
Two Dimensions ◽  
Manufacturing Processes ◽  
Layer By Layer ◽  
Repetitive Process

Additive Manufacturing (AM) processes are a class of manufacturing processes in which parts are fabricated in a layer-by-layer fashion. The layer-by-layer fabrication method creates layer-to-layer dynamics. Implementing process control that neglects the layer-to-layer dynamics can lead to process instability. While repetitive process controllers which utilize only layer-to-layer feedback are a viable method, their usefulness is limited in that they are not well-suited for tracking non-periodic layer-domain references. However, since the entire reference signal is typically known a priori in AM process fabrications, a predictive control methodology can be useful for controlling fabrications in which the reference signal is non-periodic. In this paper a model predictive control formulation is extended to two-dimensions and utilized for repetitive process control Simulation results comparing open-loop and controlled fabrications for a Laser Metal Deposition process are given.

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 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.

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