scholarly journals An Automated Open-Source Approach for Debinding Simulation in Metal Extrusion Additive Manufacturing

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Tobias Rosnitschek ◽  
Johannes Glamsch ◽  
Christopher Lange ◽  
Bettina Alber-Laukant ◽  
Frank Rieg
Keyword(s):  
Additive Manufacturing ◽  
Open Source ◽  
Selection Process ◽  
Product Development Process ◽  
Element Analysis ◽  
Powder Bed ◽  
Optimal Orientation ◽  
Automated Simulation ◽  
Manufacturing Applications ◽  
Metal Extrusion

As an alternative to powder-bed based processes, metal parts can be additively manufactured by extrusion based additive manufacturing. In this process, a highly filled polymer filament is deposited and subsequently debindered and sintered. Choosing a proper orientation of the part that satisfies the requirements of the debinding and sintering processes is crucial for a successful manufacturing process. To determine the optimal orientation for debinding, first, the part must be scaled in order to compensate the sinter induced shrinkage. Then, a finite element analysis is performed to verify that the maximum stresses due to the dead load do not exceed the critical stress limits. To ease this selection process, an approach based on open source software is shown in this article to efficiently determine a part’s optimal orientation during debinding. This automates scaling, debinding simulation, and postprocessing for all six main directions. The presented automated simulation framework is examined on three application examples and provides plausible results in a technical context for all example parts, leading to more robust part designs and a reduction of experimental trial and error. Therefore, the presented framework is a useful tool in the product development process for metal extrusion additive manufacturing applications.

scholarly journals Investigating the Mechanics of Hybrid Metal Extrusion and Bonding Additive Manufacturing by FEA

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 811 ◽  
Author(s):  
Jørgen Blindheim ◽  
Torgeir Welo ◽  
Martin Steinert
Keyword(s):  
Additive Manufacturing ◽  
Material Flow ◽  
Deposition Process ◽  
Feed Speed ◽  
Element Analysis ◽  
Reduced Pressure ◽  
Metal Structures ◽  
Material Deposition ◽  
Flow Through ◽  
Metal Extrusion

Hybrid Metal Extrusion & Bonding Additive Manufacturing (HYB-AM) is a hybrid manufacturing technology for the deposition of layered metal structures. This new deposition process is a complex metal forming operation, yet there is significant lack of knowledge regarding the governing mechanisms. In this work, we have used finite element analysis (FEA) to study material flow in the extruder, as well as the conditions at the interfaces of the deposited extrudate and the substrate, aiming to identify and characterize the process parameters involved. Analysis of the material flow shows that the extrusion pressure is virtually independent of the deposition rate. Furthermore, from the simulations of the material deposition sequence, it is clearly visible how the contact pressure at the interface will drop below the bonding threshold if the feed speed is too high relative to the material flow through the die. The reduced pressure also leads to the formation of a ‘gas-pocket’ inside the die, thus further degrading the conditions for bonding. The analyses of the process have provided valuable insights for the further development and industrialization of the process.

scholarly journals Additive Manufacturing Applications on Flexible Actuators for Active Orthoses and Medical Devices

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Michele Gabrio Antonelli ◽  
Pierluigi Beomonte Zobel ◽  
Francesco Durante ◽  
Terenziano Raparelli
Keyword(s):  
Additive Manufacturing ◽  
Acrylonitrile Butadiene Styrene ◽  
Variable Stiffness ◽  
Fused Deposition Modelling ◽  
Research Projects ◽  
Element Analysis ◽  
Pneumatic Actuators ◽  
Fused Deposition ◽  
Manufacturing Applications ◽  
Manufacturing Technologies

This paper describes the results of research projects developed at the University of L’Aquila by the research group of the authors in the field of biomedical engineering, which have seen an important use of additive manufacturing technologies in the prototyping step and, in some cases, also for the realization of preindustrialization prototypes. For these projects, commercial 3D printers and technologies such as fused deposition modelling (FDM) were used; the most commonly used polymers in these technologies are acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). The research projects concern the development of innovative actuators, such as pneumatic muscles and soft pneumatic actuators (SPAs), the development of active orthoses, such as a lower limb orthosis and, finally, the development of a variable-stiffness grasper to be used in natural orifice transluminal endoscopic surgery (NOTES). The main aspects of these research projects are described in the paper, highlighting the technologies used such as the finite element analysis and additive manufacturing.

scholarly journals An Agent-Based Decision Support Platform for Additive Manufacturing Applications

2020 ◽  
Vol 10 (14) ◽  
pp. 4953
Author(s):  
Nikolaos Papakostas ◽  
Anthony Newell ◽  
Abraham George
Keyword(s):  
Decision Support ◽  
Additive Manufacturing ◽  
Information Exchange ◽  
Product Development Process ◽  
Agent Based ◽  
Engineering Teams ◽  
Manufacturing Operations ◽  
Design Engineers ◽  
Manufacturing Resources ◽  
Manufacturing Applications

The effective estimation and consideration of process cost, time, and quality for additive manufacturing operations, when a series of suitable technologies and resources are available, is very important for making informed product design and development decisions. The main objective of this paper is to propose the design, deployment, and use of an agent-based decision support platform, which is capable of proposing alternative additive manufacturing resources and process configurations to design engineers while reducing the number of communication steps among engineering teams and organizations. Different computer-aided systems are utilised and interfaced for automating the information exchange as well as for accelerating the overall product development process.

scholarly journals Fabrication of Single Crystals through a µ-Helix Grain Selection Process during Electron Beam Metal Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 313 ◽  
Author(s):  
Martin R. Gotterbarm ◽  
Alexander M. Rausch ◽  
Carolin Körner
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Single Crystals ◽  
Electron Beam Melting ◽  
Selection Process ◽  
Powder Bed ◽  
Grain Structures ◽  
Selective Electron Beam Melting ◽  
Columnar Grain ◽  
Metal Additive

Selective Electron Beam Melting (SEBM) is a powder bed-based additive manufacturing process for metals. As the electron beam can be moved inertia-free by electromagnetic lenses, the solidification conditions can be deliberately adjusted within the process. This enables control over the local solidification conditions. SEBM typically leads to columnar grain structures. Based on numerical simulation, we demonstrated how technical single crystals develop in IN718 by forcing the temperature gradient along a µ-Helix. The slope of the µ-Helix, i.e., the deviation of the thermal gradient from the build direction, determined the effectiveness of grain selection right up to single crystals.

scholarly journals DEVELOPMENT OF LOW-COST ADDITIVE MANUFACTURING SYSTEM THROUGH SELECTIVE INHIBITION SINTERING (SIS) PROCESS AND EVALUATION OF MECHANICAL CHARACTERISTICS OF FABRICATED PARTS

2020 ◽  
Vol 21 (2) ◽  
pp. 212-229
Author(s):  
Mesfin Sisay Mengesha ◽  
E. Balasubramanian ◽  
P. Arunkumar ◽  
M. Silambarasan ◽  
D. Rajamani
Keyword(s):  
Experimental Investigation ◽  
Additive Manufacturing ◽  
Open Source ◽  
Material Selection ◽  
Low Cost ◽  
Control Unit ◽  
Cost Effective ◽  
Selective Inhibition ◽  
Element Analysis ◽  
Selective Inhibition Sintering

Additive manufacturing (AM) is widely being used in today’s contemporary industry; however, products fabricated by the existing AM techniques are costly due to the high machine cost and low production rate. Therefore, the focus of this work is to design and fabricate a cost-effective and novel powder based selective inhibition sintering (SIS) system. Various subsystems of the machine such as the infrared heater assembly, inhibition deposition mechanism, build and feed tank assemblies, powder deposition, and the compaction system have been indigenously designed and fabricated. An electronic control system is also established through integrating sensors, linear and rotary actuators, belt and pulley mechanism, and temperature feedback control unit. The customized SIS system is developed by integrating the assembly of all the subsystems, and the electronic modules with an open-source platform to generate the necessary motion characteristics. Besides, an open source RepRap user interface firmware has been used to control the machine. Thermo-structural finite element analysis has been used to study the sintering behaviour of powder material. Inhibitor material selection and preparation have been carried out by performing an experimental investigation on the inhibition effects of various materials. The machine has been tested through fabricating parts from HDPE polymer powder. Finally, the performance of the produced parts has been evaluated by conducting an experimental investigation. The results of the investigation indicated that the fabricated parts have attained sufficient mechanical strength and, hence, the developed SIS system can be utilized to manufacture functional parts. ABSTRAK: Industri pembuatan bahan tambahan (AM) banyak digunakan dalam industri kontemporari semasa; walau bagaimanapun, produk yang terhasil daripada teknik sedia ada AM adalah mahal disebabkan harga mesin yang mahal dan kadar penghasilan yang rendah. Oleh itu, tujuan kajian ini adalah bagi mereka cipta serbuk baharu dengan harga berpatutan berdasarkan sistem pensinteran rencatan pilihan (SIS). Pelbagai mesin subsistem seperti pemasangan pemanas inframerah, mekanisme pemendapan rencatan, binaan dan pemasangan tangki suapan, deposisi serbuk, dan sistem pemadatan telah direka cipta secara alami dan dipasang siap. Sistem kawalan elektronik juga diadakan melalui integrasi sensor, lelurus dan penggerak putaran, jaluran dan mekanisme takal dan suhu unit kawalan suap balik. Sistem SIS yang dibuat mengikut pesanan ini dihasilkan dengan mengintegrasi pemasangan kesemua subsistem, dan modul elektronik melalui platfom sumber terbuka bagi menghasilkan ciri-ciri pergerakan bersesuaian. Selain itu, sumber terbuka RepRap perisian tegar antara muka telah digunakan bagi mengawal mesin. Analisis unsur terhingga struktur-terma digunakan bagi mempelajari perihal pensinteran bahan serbuk. Pilihan bahan perencat dan persediaan telah dijalankan dengan menjalankan siasatan eksperimen pada kesan perencat pelbagai bahan. Mesin diuji melalui pemasangan bahagian daripada HDPE serbuk polimer. Akhirnya, bahagian yang terhasil diuji melalui ujian eksperimen. Hasil kajian menunjukkan pemasangan bahagian telah mencapai kekuatan mekanikal mencukupi, dengan itu sistem SIS yang dibina boleh digunakan bagi mengilang bahagian berkaitan.

Model Guided Mixing of Ceramic Powders With Graded Particle Sizes in Binder Jetting Additive Manufacturing

2018 ◽  
Author(s):  
Wenchao Du ◽  
Xiaorui Ren ◽  
Yexiao Chen ◽  
Chao Ma ◽  
Miladin Radovic ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Packing Density ◽  
Ternary Mixture ◽  
Sintered Density ◽  
Selection Process ◽  
Ternary Mixtures ◽  
Particle Sizes ◽  
Mixed Powder ◽  
Powder Bed ◽  
Binder Jetting

Binder jetting additive manufacturing is a promising technology for fabricating ceramic parts with complex or customized geometries. However, this process is limited by the relatively low density of the fabricated parts even after sintering. This paper reports a study on effects of mixing powders with graded particle sizes on the powder bed packing density and consequently the sintered density. For the first time, a linear packing model, which can predict the packing density of mixed powders, has been used to guide the selection of particle sizes and fractions of constituent powders. A selection process was constructed to obtain the maximum mixed packing density. In the part of model validation, three types of alumina powders with average sizes of 2 μm, 10 μm, and 70 μm, respectively, were mixed in optimum volumetric fractions that could lead to the maximum packing density based on model predictions. Powder bed packing density was measured on binary mixtures, ternary mixture, and each constituent powders. Furthermore, disk-shaped samples were made, using binder jetting additive manufacturing, from each constituent and mixed powder. Results show that binary and ternary mixtures have higher powder bed packing densities and sintered densities than the corresponding constituent powders. The disks made from the ternary mixture achieved the highest sintered density of 65.5%.

scholarly journals Topology Optimization for Additive Manufacturing as an Enabler for Light Weight Flight Hardware

Designs ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 51 ◽  
Author(s):  
Melissa Orme ◽  
Ivan Madera ◽  
Michael Gschweitl ◽  
Michael Ferrari
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Case Studies ◽  
Space Mission ◽  
Element Analysis ◽  
Powder Bed ◽  
Satellite Technology ◽  
Process Testing ◽  
Qualification Testing ◽  
Flight Hardware

Three case studies utilizing topology optimization and Additive Manufacturing for the development of space flight hardware are described. The Additive Manufacturing (AM) modality that was used in this work is powder bed laser based fusion. The case studies correspond to the redesign and manufacture of two heritage parts for a Surrey Satellite Technology LTD (SSTL) Technology Demonstrator Space Mission that are currently functioning in orbit (case studies 1 and 2), and a system of five components for the SpaceIL’s lunar launch vehicle planned for launch in the near future (case study 3). In each case, the nominal or heritage part has undergone topology optimization, incorporating the AM manufacturing constraints that include: minimization of support structures, ability to remove unsintered powder, and minimization of heat transfer jumps that will cause artifact warpage. To this end the topology optimization exercise must be coupled to the Additive Manufacturing build direction, and steps are incorporated to integrate the AM constraints. After design verification by successfully passing a Finite Element Analysis routine, the components have been fabricated and the AM artifacts and in-process testing coupons have undergone verification and qualification testing in order to deliver structural components that are suitable for their respective missions.

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