scholarly journals Integration of Topology Optimisation and Design Variants Selection for Additive Manufacturing-Based Systematic Product Redesign

2020 ◽  
Vol 10 (21) ◽  
pp. 7841
Author(s):  
Enrico Dalpadulo ◽  
Francesco Gherardini ◽  
Fabio Pini ◽  
Francesco Leali
Keyword(s):  
Additive Manufacturing ◽  
Assistive Device ◽  
Topology Optimisation ◽  
Fused Filament Fabrication ◽  
Parameters Selection ◽  
Critical Issues ◽  
Product And Process ◽  
Definition Of ◽  
Manufacturing Technologies ◽  
Selection Of

The development of additive manufacturing allows the transformation of technological processes and the redesign of products. Among the most used methods to support additive manufacturing, the design can be optimised through the integration of topology optimisation techniques, allowing for creating complex shapes. However, there are critical issues (i.e., definition of product and process parameters, selection of redesign variants, optimised designs interpretation, file exchange and data management, etc.) in identifying the most appropriate process and set-ups, as well as in selecting the best variant on a functional and morphological level. Therefore, to fully exploit the technological potentials and overcome the drawbacks, this paper proposes a systematic redesign approach based on additive manufacturing technologies that integrate topology optimisation and a tool for selecting design variants based on the optimisation of both product and process features. The method leads to the objective selection of the best redesigned configuration in accordance with the key performance indicators (KPIs) (i.e., functional and production requirements). As a case study, the redesign of a medical assistive device is proposed, previously developed in fused filament fabrication and now optimised for being 3D printed with selective laser melting.

scholarly journals Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1036
Author(s):  
Daniel Moreno Nieto ◽  
María Alonso-García ◽  
Miguel-Angel Pardo-Vicente ◽  
Lucía Rodríguez-Parada
Keyword(s):  
Additive Manufacturing ◽  
Product Design ◽  
Control Sample ◽  
Polymeric Materials ◽  
Degradation Process ◽  
Fused Filament Fabrication ◽  
End Use ◽  
Definition Of ◽  
Manufacturing Technologies ◽  
Saturated Solutions

Additive manufacturing technologies are shifting from rapid prototyping technologies to end use or final parts production. Polymeric material extrusion processes have been broadly addressed with a specific definition of all parameters and variables for all different of technologies approaches and materials. Recycled polymeric materials have been studied due to the growing importance of the environmental awareness of the contemporary society. Beside this, little specific research has been found in product development applications for AM where the printed parts are in highly moisture environments or surrounded by water, but polymers have been for long used in such industries with conventional manufacturing approaches. This work focuses on the analysis and comparison of two different additively manufactured polymers printed by fused filament fabrication (FFF) processes using desktop-size printers to be applied for product design. The polymers used have been a recycled material: polyethylene terephthalate glycol (PETG) and polylactic acid (PLA). Degradation and water absorption behaviors of both materials are presented, analyzed and discussed in this paper, where different samples have been immersed in saturated solutions of water with maritime salt and sugar together with a control sample immersed in distilled water. The samples have been dimensionally and weight-controlled weekly as well as microscopically analyzed to understand degradation and absorption processes that appear in the fully saturated solutions. The results revealed how the absorption process is stabilized after a reduced number of weeks for both materials and how the degradation process is more remarked in the PLA material due to its organic nature.

Additive manufacturing of zirconia parts by fused filament fabrication and solvent debinding: Selection of binder formulation

2019 ◽  
Vol 26 ◽  
pp. 117-128 ◽  
Author(s):  
Santiago Cano ◽  
Joamin Gonzalez-Gutierrez ◽  
Janak Sapkota ◽  
Martin Spoerk ◽  
Florian Arbeiter ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Fused Filament Fabrication ◽  
Selection Of

Innovative approaches to designing and manufacturing a prosthetic thumb

2020 ◽  
pp. 030936462094971 ◽  
Author(s):  
Branko Štefanovič ◽  
Monika Michalíková ◽  
Lucia Bednarčíková ◽  
Marianna Trebuňová ◽  
Jozef Živčák
Keyword(s):  
Additive Manufacturing ◽  
3D Scanning ◽  
Metacarpal Bone ◽  
Point Of View ◽  
Dominant Hand ◽  
Fused Filament Fabrication ◽  
Conventional Methods ◽  
Manufacturing Technologies ◽  
The Right ◽  
Manufacturing Time

Case description: Conventional methods for producing custom prosthetic fingers are time-consuming, can be uncomfortable for the patient, and require a skilled prosthetist. The subject was a 40-year-old male with congenital absence of the thumb and related metacarpal bone on the right non-dominant hand, anomaly of the lengths of individual upper limb segments, and contracture of the elbow joint. This hand presentation made it impossible for him to perform thumb opposition, which is a very important function for common daily activities. Objective: The goal was to design an individual passive thumb prosthesis using free open-source software, 3D scanning technology, and additive manufacturing methods (i.e., fused filament fabrication). Study design: Case report. Treatment: Artificial thumb prostheses with two types of bases and fastening interfaces were designed and manufactured. One combination was chosen as the best alternative. Outcomes: The shape, positioning, firmness, and fastening of the prosthesis were compliant enough for the patient to be able to hold objects with his healthy fingers and artificial thumb. This innovative approach to fabrication of a custom thumb prosthesis provided considerable advantages in terms of custom sizing, manufacturing time, rapid production, iteration, comfort, and costs when compared to conventional methods of manufacturing a hand prosthesis. Conclusion: The methodology of designing and manufacturing a prosthetic thumb using 3D scanning and additive manufacturing technologies have been demonstrated to be adequate from a practical point of view. These technologies show potential for use in the practice of prosthetics.

scholarly journals A 3D weaving infill pattern for fused filament fabrication

2021 ◽  
Author(s):  
Yuan Yao ◽  
Cheng Ding ◽  
Mohamed Aburaia ◽  
Maximilian Lackner ◽  
Lanlan He
Keyword(s):  
Additive Manufacturing ◽  
Three Dimensional ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Repetitive Structure ◽  
Mechanical Linkage ◽  
Manufacturing Technologies ◽  
Dimensional Object ◽  
Anisotropy Of Mechanical Properties ◽  
3D Weaving

Abstract The Fused Filament Fabrication process is the most used additive manufacturing process due to its simplicity and low operating costs. In this process, a thermoplastic filament is led through an extruder, melted, and applied to a building platform by the axial movements of an automated Cartesian system in such a way that a three-dimensional object is created layer by layer. Compared to other additive manufacturing technologies, the components produced have mechanical limitations and are often not suitable for functional applications. To reduce the anisotropy of mechanical strength in fused filament fabrication (FFF), this paper proposes a 3D weaving deposit path planning method that utilizes a 5-layer repetitive structure to achieve interlocking and embedding between neighbor slicing planes to improve the mechanical linkage within the layers. The developed algorithm extends the weaving path as an infill pattern to fill different structures and makes this process feasible on a standard three-axis 3D printer. Compared with 3D weaving printed parts by layer-to-layer deposit, the anisotropy of mechanical properties inside layers is significantly reduced to 10.21% and 0.98%.

scholarly journals Processing of Sr2+ Containing Poly L-Lactic Acid-Based Hybrid Composites for Additive Manufacturing of Bone Scaffolds

2020 ◽  
Vol 7 ◽  
Author(s):  
Priscila Melo ◽  
Raasti Naseem ◽  
Ilaria Corvaglia ◽  
Giorgia Montalbano ◽  
Carlotta Pontremoli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Additive Manufacturing ◽  
Hybrid Composites ◽  
Homogeneous Distribution ◽  
Fused Filament Fabrication ◽  
Rheological Characterization ◽  
Biodegradable Composite ◽  
Manufacturing Technologies

Biodegradable composite materials represent one of the major areas of investigation for bone tissue engineering due to their tuneable compositional and mechanical properties, which can potentially mimic those of bone and potentially avoid the removal of implants, mitigating the risks for the patient and reducing the overall clinical costs. In addition, the introduction of additive manufacturing technologies enables a strict control over the final morphological features of the scaffolds. In this scenario, the optimisation of 3D printable resorbable composites, made of biocompatible polymers and osteoinductive inorganic phases, offers the potential to produce a chemically and structurally biomimetic implant, which will resorb over time. The present work focuses on the development and process optimisation of two hybrid composite filaments, to be used as feedstock for the fused filament fabrication 3D printing process. A Poly L-lactic acid matrix was blended with either rod-like nano-hydroxyapatite (nano-HA) or nanoparticles of mesoporous bioactive glasses, both partially substituted with strontium (Sr2+), due to the well-known pro-osteogenic effect of this ion. Both inorganic phases were incorporated into Poly L-lactic acid using an innovative combination of processes, obtaining a homogeneous distribution throughout the polymer whilst preserving their ability to release Sr2+. The filament mechanical properties were not hindered after the incorporation of the inorganic phases, resulting in tensile strengths and moduli within the range of cancellous bone, 50 ± 10 MPa and 3 ± 1 GPa. Finally, the rheological characterization of the hybrid composites indicated a shear thinning behaviour, ideal for the processing with fused filament fabrication, proving the potential of these materials to be processed into 3D structures aiming bone regeneration.

On the Capabilities of a Multi-Modality 3D Bioprinter for Customized Biomedical Devices

2015 ◽  
Author(s):  
Prashanth Ravi ◽  
Panos S. Shiakolas ◽  
Tre Welch ◽  
Tushar Saini ◽  
Kristine Guleserian ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Device Fabrication ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Stl File ◽  
Diverse Application ◽  
Multiple Materials ◽  
Manufacturing Platform ◽  
Single Construct ◽  
Manufacturing Technologies

Currently, there is a major shift in medical device fabrication research towards layer-by-layer additive manufacturing technologies; mainly owing to the relatively quick transition from a solid model (.STL file) to an actual prototype. The current manuscript introduces a Custom Multi-Modality 3D Bioprinter (CMMB) developed in-house, combining the Fused Filament Fabrication (FFF), Photo Polymerization (PP), Viscous Extrusion (VE), and Inkjet (IJ) printing technologies onto a single additive manufacturing platform. Methodologies to address limitation in the ability to customize construct properties layer-by-layer and to incorporate multiple materials in a single construct have been evaluated using open source 3D printing softwares Slic3r and Repetier-Host. Such customization empowers the user to fabricate constructs with tailorable anisotropic properties by combining different print technologies and materials. To this end, procedures which allow the integration of more than one distinct modality of the CMMB during a single print session were developed and evaluated, and are discussed. The current setup of the CMMB provides the capability to fabricate personalized medical devices using patient data from an MRI or a CT scan. Initial experiments and fabricated constructs demonstrate the potential of the CMMB for research in diverse application areas within biomedical engineering.

scholarly journals Analytical and Numerical Models of Thermoplastics: A Review Aimed to Pellet Extrusion-Based Additive Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3160
Author(s):  
Alessio Pricci ◽  
Marco D. de Tullio ◽  
Gianluca Percoco
Keyword(s):  
Fluid Dynamics ◽  
Additive Manufacturing ◽  
Numerical Models ◽  
Fused Filament Fabrication ◽  
First Case ◽  
Recent Developments ◽  
Physical And Chemical ◽  
Pellet Extrusion ◽  
Selection Of ◽  
Reduction Of Costs

Recent developments in additive manufacturing have moved towards a new trend in material extrusion processes (ISO/ASTM 52910:2018), dealing with the direct extrusion of thermoplastic and composite material from pellets. This growing interest is driven by the reduction of costs, environmental impact, energy consumption, and the possibility to increase the range of printable materials. Pellet additive manufacturing (PAM) can cover the same applications as fused filament fabrication (FFF), and in addition, can lead to scale towards larger workspaces that cannot be covered by FFF, due to the limited diameters of standard filaments. In the first case, the process is known as micro- or mini-extrusion (MiE) in the literature, in the second case the expression big area additive manufacturing (BAAM) is very common. Several models are available in literature regarding filament extrusion, while there is a lack of modeling of the extrusion dynamics in PAM. Physical and chemical phenomena involved in PAM have high overlap with those characterizing injection molding (IM). Therefore, a systematic study of IM literature can lead to a selection of the most promising models for PAM, both for lower (MiE) and larger (BAAM) extruder dimensions. The models concerning the IM process have been reviewed with this aim: the extraction of information useful for the development of codes able to predict thermo-fluid dynamics performances of PAM extruders.

scholarly journals Review of the Hard-Facing Technology Application for Reparation of the Given Parts in Various Branches of Industry

2018 ◽  
Vol 1 (1) ◽  
pp. 279-285
Author(s):  
Vukić Lazić ◽  
Dušan Arsić ◽  
Milan Mutavdžić ◽  
Ružica Nikolić ◽  
Jozef Meško ◽  
...  
Keyword(s):  
Filler Metal ◽  
Technology Application ◽  
Post Process ◽  
Parameters Selection ◽  
Complex Shapes ◽  
Machine Parts ◽  
Definition Of ◽  
The Right ◽  
The Given ◽  
Selection Of

Abstract This paper deals with the problem of defining the optimal procedure for reparation of the machine parts of large dimensions and complex shapes. The procedure consists of establishing the causes of the part's damages, definition of the reparation technology, with selection of its parameters and ways of execution. The reparation is done by hard-facing, with heat treatment that consists of preheating, additional heating and the post hard-facing tempering. The process parameters' selection includes choosing the right filler metal(s), ways and order of depositing the hard-faced layers, ways of reaching and maintaining the preheating temperatures, checking of the base metal's chemical composition and mechanical properties and deciding on the post-process heat and mechanical processing of the executed hard-facing. The executed reparation of the forging hammer's mallet, presented in details, serves as an example how the reparation can successfully serve as a substitute for procuring the new part and thus producing the savings both directly in lower costs and indirectly in shortening the down-time of the damaged part operation.

scholarly journals Selection of additive manufacturing technologies in productive systems: a decision support model

2020 ◽  
Vol 27 (3) ◽  
Author(s):  
Douglas Rhoden Calderaro ◽  
Daniel Pacheco Lacerda ◽  
Douglas Rafael Veit
Keyword(s):  
Decision Support ◽  
Additive Manufacturing ◽  
Production System ◽  
Global Economy ◽  
Additive Technologies ◽  
Technology Selection ◽  
Decision Support Model ◽  
Manufacturing Technologies ◽  
Selection Of ◽  
Support Model

Abstract: Additive Manufacturing (AM) has seen continued growth in adoption by organizations in recent years, changing production processes, supply chain, maintenance, product development and the global economy. There are several Additive Manufacturing technologies and equipment on the market, however, there are no guidelines, benchmarking or decision support tools for proper selection. After a systematic review of the literature, the lack of propositions that act during the development of the product and process was evidenced. This research focuses on the selection of Additive Manufacturing technologies for a production system. The general objective being to propose a decision support model based on the characteristics of additive technologies and competitive criteria, resulting in a choice aligned with the guidelines of organizations and their production systems. For the operationalization of the model, the AHP techniques and conjoint analysis were used together, where the characteristics of the Additive Manufacturing technologies were related to the competitive criteria for the model to indicate the recommended technology to the production system or organization in question. Finally, the artifact recommended the right technology in three distinct situations, from a vendor, user, and expert point of view. Thus, this research contributes to both academia and business by developing a functional artifact of additive manufacturing technology selection. Also, by contributing to the increased availability of information on the nine most commonly used additive technologies in industry.

scholarly journals Effects of Two Melt Extrusion Based Additive Manufacturing Technologies and Common Sterilization Methods on the Properties of a Medical Grade PLGA Copolymer

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 572
Author(s):  
Marion Gradwohl ◽  
Feng Chai ◽  
Julien Payen ◽  
Pierre Guerreschi ◽  
Philippe Marchetti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Additive Manufacturing ◽  
Ethylene Oxide ◽  
Medical Devices ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Manufacturing Technologies ◽  
Medical Grade

Although bioabsorbable polymers have garnered increasing attention because of their potential in tissue engineering applications, to our knowledge there are only a few bioabsorbable 3D printed medical devices on the market thus far. In this study, we assessed the processability of medical grade Poly(lactic-co-glycolic) Acid (PLGA)85:15 via two additive manufacturing technologies: Fused Filament Fabrication (FFF) and Direct Pellet Printing (DPP) to highlight the least destructive technology towards PLGA. To quantify PLGA degradation, its molecular weight (gel permeation chromatography (GPC)) as well as its thermal properties (differential scanning calorimetry (DSC)) were evaluated at each processing step, including sterilization with conventional methods (ethylene oxide, gamma, and beta irradiation). Results show that 3D printing of PLGA on a DPP printer significantly decreased the number-average molecular weight (Mn) to the greatest extent (26% Mn loss, p < 0.0001) as it applies a longer residence time and higher shear stress compared to classic FFF (19% Mn loss, p < 0.0001). Among all sterilization methods tested, ethylene oxide seems to be the most appropriate, as it leads to no significant changes in PLGA properties. After sterilization, all samples were considered to be non-toxic, as cell viability was above 70% compared to the control, indicating that this manufacturing route could be used for the development of bioabsorbable medical devices. Based on our observations, we recommend using FFF printing and ethylene oxide sterilization to produce PLGA medical devices.

Sign in / Sign up

Export Citation Format

Share Document