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.

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.

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.

Design Process Deconstructed: The Industry Case of an Elevator Button Assembly Redesigned for Additive Manufacturing

2019 ◽  
Author(s):  
Tuomas Puttonen
Keyword(s):  
Functional Analysis ◽  
Additive Manufacturing ◽  
Design Process ◽  
Efficient Design ◽  
3D Design ◽  
Design Methodologies ◽  
Current Design ◽  
Volume Product ◽  
End Use ◽  
Manufacturing Technologies

Abstract Additive manufacturing (AM) has during the 21st century gradually shifted from prototyping towards the manufacture of end-use quality parts. The drivers to utilize AM instead of conventional manufacturing methods are often linked to geometrical design freedom, increased performance, customization, part consolidation, and weight reduction. However, designers have struggled to take full advantage of these new capabilities. In part, this is due to a pervasive engineering mindset locked into the constraints of conventional manufacturing technologies. Another reason is the lack of efficient design methodologies that would take into account the new capabilities of AM. In this paper, to address the latter deficiency, an assembly redesign process for AM is deconstructed and analyzed. The studied assembly is an elevator accessibility button, which is a high-mix low-volume product. From the industry perspective, AM could reduce costs and increase the agility of production. Through systematic requirements mapping, part- and product-level functional analysis, a holistic functional analysis of the product is composed. The results of the product functional analysis are illustrated in a visual 3D design space. The 3D illustration is suggested as a conceptualization tool for the designers and as a way to reinforce creativity in the design process. The usability and expandability of the tool are discussed and contrasted with the current design methodologies for AM.

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.

scholarly journals Shape and volume optimization of industrial parts

2022 ◽  
Vol 10 (1) ◽  
pp. 058-064
Author(s):  
Juraj Beniak ◽  
Miloš Matúš ◽  
Ľubomír Šooš ◽  
Peter Križan
Keyword(s):  
Additive Manufacturing ◽  
Strength Properties ◽  
Production Costs ◽  
Topological Optimization ◽  
Material Consumption ◽  
Great Pressure ◽  
End Use ◽  
Manufacturing Technologies ◽  
Original Part

In the present time, there are many challenges in the production of industrial parts. Due to the constantly rising prices of materials and energy, it is necessary to constantly look for ways to optimize production costs and optimize material consumption. There is great pressure on economical production, i. to produce products with the lowest costs given the expected and necessary properties. With the introduction of additive manufacturing technologies into practice and the production of parts for end use comes the introduction of methods for optimizing the shape of the part and the required amount of material for its production. We call this method Topological Optimization. The presented article describes the preparation of topologically optimized parts and a comparison of their strength properties with respect to the original and the original part.

scholarly journals An Overview on Personal Protective Equipment (PPE) Fabricated with Additive Manufacturing Technologies in the Era of COVID-19 Pandemic

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2703 ◽  
Author(s):  
Szilard Rendeki ◽  
Balint Nagy ◽  
Matyas Bene ◽  
Attila Pentek ◽  
Luca Toth ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Open Source ◽  
Personal Protective Equipment ◽  
Face Mask ◽  
Protective Equipment ◽  
Fused Filament Fabrication ◽  
Small Series ◽  
Source Models ◽  
3D Printed ◽  
Manufacturing Technologies

Different additive manufacturing technologies have proven effective and useful in remote medicine and emergency or disaster situations. The coronavirus disease 2019 (COVID-19) disease, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus, has had a huge impact on our society, including in relation to the continuous supply of personal protective equipment (PPE). The aim of the study is to give a detailed overview of 3D-printed PPE devices and provide practical information regarding the manufacturing and further design process, as well as describing the potential risks of using them. Open-source models of a half-face mask, safety goggles, and a face-protecting shield are evaluated, considering production time, material usage, and cost. Estimations have been performed with fused filament fabrication (FFF) and selective laser sintering (SLS) technology, highlighting the material characteristics of polylactic acid (PLA), polyamide, and a two-compound silicone. Spectrophotometry measurements of transparent PMMA samples were performed to determine their functionality as goggles or face mask parts. All the tests were carried out before and after the tetra-acetyl-ethylene-diamine (TAED)-based disinfection process. The results show that the disinfection has no significant effect on the mechanical and structural stability of the used polymers; therefore, 3D-printed PPE is reusable. For each device, recommendations and possible means of development are explained. The files of the modified models are provided. SLS and FFF additive manufacturing technology can be useful tools in PPE development and small-series production, but open-source models must be used with special care.

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