scholarly journals The 3D Printing of Freestanding PLLA Thin Layers and Improving First Layer Consistency through the Introduction of Sacrificial PVA

2021 ◽  
Vol 11 (14) ◽  
pp. 6320
Author(s):  
David M. Roper ◽  
Kyung-Ah Kwon ◽  
Serena M. Best ◽  
Ruth E. Cameron
Keyword(s):  
Thin Layers ◽  
Patient Specific ◽  
Thickness Variation ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Thin Structures ◽  
Complex Patient ◽  
Layer Deposition ◽  
Layer Structures ◽  
3D Printed

Fused filament fabrication (FFF) is an inexpensive way of producing objects through a programmed layer-by-layer deposition. For multi-layer, macro-scaled prints, acceptable printing is achieved provided, amongst other factors, first layer adhesion is sufficient to fix a part to the surface during printing. However, in the deposition of structures with a single or few layers, first layer consistency is significantly more important and is an issue that has been previously overlooked. As layer-to-bed adhesion is prioritised in first layer printing, thin layer structures are difficult to remove without damage. The deposition of controllable thin structures has potential in tissue engineering through the use of bioactive filaments and incorporation of microfeatures into complex, patient-specific scaffolds. This paper presents techniques to progress the deposition of thin, reproducible structures. The linear thickness variation of 3D-printed single PVA and PLLA layers is presented as a function of extrusion factor and the programmed vertical distance moved by the nozzle between layers (the layer separation). A sacrificial PVA layer is shown to significantly improve first layer consistency, reducing the onus on fine printer calibration in the deposition of single layers. In this way, the linear variation in printed single PLLA layers with bed deviation is drastically reduced. Further, this technique is used to demonstrate the printing of freestanding thin layers of ~25 µm in thickness.

scholarly journals Metallization of Thermoplastic Polymers and Composites 3D Printed by Fused Filament Fabrication

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Paolo Tralli ◽  
Stefano Turri ◽  
Marinella Levi ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Test Sample ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Post Processing ◽  
Thermoplastic Polymers ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Manufacturing Technologies

Fused filament fabrication allows the direct manufacturing of customized and complex products although the layer-by-layer appearance of this process strongly affects the surface quality of the final parts. In recent years, an increasing number of post-processing treatments has been developed for the most used materials. Contrarily to other additive manufacturing technologies, metallization is not a common surface treatment for this process despite the increasing range of high-performing 3D printable materials. The objective of this work is to explore the use of physical vapor deposition sputtering for the chromium metallization of thermoplastic polymers and composites obtained by fused filament fabrication. The thermal and mechanical properties of five materials were firstly evaluated by means of differential scanning calorimetry and tensile tests. Meanwhile, a specific finishing torture test sample was designed and 3D printed to perform the metallization process and evaluate the finishing on different geometrical features. Furthermore, the roughness of the samples was measured before and after the metallization, and a cost analysis was performed to assess the cost-efficiency. To sum up, the metallization of five samples made with different materials was successfully achieved. Although some 3D printing defects worsened after the post-processing treatment, good homogeneity on the finest details was reached. These promising results may encourage further experimentations as well as the development of new applications, i.e., for the automotive and furniture fields.

scholarly journals Fabricating Lattice Structures via 3D Printing: The Case of Porous Bio-Engineered Scaffolds

2021 ◽  
Vol 2 (2) ◽  
pp. 289-302
Author(s):  
Antreas Kantaros ◽  
Dimitrios Piromalis
Keyword(s):  
3D Printing ◽  
Great Accuracy ◽  
Patient Specific ◽  
Layer By Layer ◽  
Printing Technology ◽  
3D Printing Technology ◽  
Geometry Design ◽  
Layer Deposition ◽  
Controlled Porosity ◽  
Porosity Percentage

Over time, the fabrication of lattice, porous structures has always been a controversial field for researchers and practitioners. Such structures could be fabricated in a stochastic way, thus, with limited control over the actual porosity percentage. The emerging technology of 3D printing, offered an automated process that did not require the presence of molds and operated on a layer-by-layer deposition basis, provided the ability to fabricate almost any shape through a variety of materials and methods under the umbrella of the ASTM terminology “additive manufacturing”. In the field of biomedical engineering, the technology was embraced and adopted for relevant applications, offering an elevated degree of design freedom. Applications range in the cases where custom-shaped, patient-specific items have to be produced. Scaffold structures were already a field under research when 3D printing was introduced. These structures had to act as biocompatible, bioresorbable and biodegradable substrates, where the human cells could attach and proliferate. In this way, tissue could be regenerated inside the human body. One of the most important criteria for such a structure to fulfil is the case-specific internal geometry design with a controlled porosity percentage. 3D printing technology offered the ability to tune the internal porosity percentage with great accuracy, along with the ability to fabricate any internal design pattern. In this article, lattice scaffold structures for tissue regeneration are overviewed, and their evolution upon the introduction of 3D printing technology and its employment in their fabrication is described.

scholarly journals Layer-By-Layer: The Case for 3D Bioprinting Neurons to Create Patient-Specific Epilepsy Models

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3218 ◽  
Author(s):  
Natasha Antill-O’Brien ◽  
Justin Bourke ◽  
Cathal D. O’Connell
Keyword(s):  
Three Dimensional ◽  
3D Models ◽  
Patient Specific ◽  
Layer By Layer ◽  
3D Bioprinting ◽  
3D Structures ◽  
Neuronal Populations ◽  
Layer Deposition ◽  
Epilepsy Models ◽  
Ink Formulation

The ability to create three-dimensional (3D) models of brain tissue from patient-derived cells, would open new possibilities in studying the neuropathology of disorders such as epilepsy and schizophrenia. While organoid culture has provided impressive examples of patient-specific models, the generation of organised 3D structures remains a challenge. 3D bioprinting is a rapidly developing technology where living cells, encapsulated in suitable bioink matrices, are printed to form 3D structures. 3D bioprinting may provide the capability to organise neuronal populations in 3D, through layer-by-layer deposition, and thereby recapitulate the complexity of neural tissue. However, printing neuron cells raises particular challenges since the biomaterial environment must be of appropriate softness to allow for the neurite extension, properties which are anathema to building self-supporting 3D structures. Here, we review the topic of 3D bioprinting of neurons, including critical discussions of hardware and bio-ink formulation requirements.

scholarly journals 3D printed patient-specific bone models for anatomy education from medical imaging

2021 ◽  
Author(s):  
Arivazhagan Pugalendhi ◽  
◽  
SenthilMurugan Arumugam ◽  
Rajesh Ranganathan ◽  
Sivakumar Ganesan ◽  
...  
Keyword(s):  
3D Printing ◽  
Surgical Planning ◽  
Thin Layers ◽  
Physical Models ◽  
Patient Specific ◽  
Anatomy Education ◽  
Healthcare Applications ◽  
Surgical Guides ◽  
Solid Objects ◽  
3D Printed

Evolution of 3D printing from medical image datasets are escalating and has widespread in healthcare applications such as anatomical models, surgical guides, and customized implants. In 3D printing, solid objects are fabricated by the frequently added the thin layers of material as per the digital model. This paper demonstrates the fabrication of 3D printed patient-specific bone models of leg and ankle foot from Digital Imaging and Communications in Medicine (DICOM) files. Processing of DICOM file is prepared by D2P (DICOM to PRINT) software and physical models are produced by Stratasys uPrint 3D printer. This 3D printed anatomical model eliminates the requirement of actual human bones, significance of preservation and mistakes in assembly of bones. The results of the study not only encourage education, surgical planning and validating medical devices but stimulate exciting innovations.

scholarly journals A Multi-Criteria Assessment Strategy for 3d Printed Porous Polyetheretherketone (Peek) Patient-Specific Implants for Orbital Wall Reconstruction

2021 ◽  
Author(s):  
Neha Sharma ◽  
Dennis Welker ◽  
Soheila Aghlmandi ◽  
Michaela Maintz ◽  
Hans-Florian Zeilhofer ◽  
...  
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Fused Filament Fabrication ◽  
Decision Matrix ◽  
Maximum Deformation ◽  
Patient Specific Implants ◽  
High Durability ◽  
Orbital Wall ◽  
3D Printed

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient's unique anatomy. Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

scholarly journals Printing 3D Hydrogel Structures Employing Low-Cost Stereolithography Technology

2020 ◽  
Vol 11 (1) ◽  
pp. 12 ◽  
Author(s):  
Leila Samara S. M. Magalhães ◽  
Francisco Eroni Paz Santos ◽  
Conceição de Maria Vaz Elias ◽  
Samson Afewerki ◽  
Gustavo F. Sousa ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Low Cost ◽  
Three Dimensional ◽  
Laser Source ◽  
Layer By Layer ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Layer Structures ◽  
Complex Models ◽  
3D Printed

Stereolithography technology associated with the employment of photocrosslinkable, biocompatible, and bioactive hydrogels have been widely used. This method enables 3D microfabrication from images created by computer programs and allows researchers to design various complex models for tissue engineering applications. This study presents a simple and fast home-made stereolithography system developed to print layer-by-layer structures. Polyethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA) hydrogels were employed as the photocrosslinkable polymers in various concentrations. Three-dimensional (3D) constructions were obtained by using the stereolithography technique assembled from a commercial projector, which emphasizes the low cost and efficiency of the technique. Lithium phenyl-2,4,6-trimethylbenzoyl phosphonate (LAP) was used as a photoinitiator, and a 404 nm laser source was used to promote the crosslinking. Three-dimensional and vascularized structures with more than 5 layers and resolutions between 42 and 83 µm were printed. The 3D printed complex structures highlight the potential of this low-cost stereolithography technique as a great tool in tissue engineering studies, as an alternative to bioprint miniaturized models, simulate vital and pathological functions, and even for analyzing the actions of drugs in the human body.

scholarly journals Effect of Fibre Orientation on Novel Continuous 3D-Printed Fibre-Reinforced Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2524
Author(s):  
Ilaria Papa ◽  
Alessia Teresa Silvestri ◽  
Maria Rosaria Ricciardi ◽  
Valentina Lopresto ◽  
Antonino Squillace
Keyword(s):  
Low Cost ◽  
High Strength ◽  
Raw Material ◽  
Layer By Layer ◽  
Compression Tests ◽  
Fused Filament Fabrication ◽  
Calorimetric Analysis ◽  
Surface Finishes ◽  
3D Printed ◽  
Manufacturing Techniques

Among the several additive manufacturing techniques, fused filament fabrication (FFF) is a 3D printing technique that is fast, handy, and low cost, used to produce complex-shaped parts easily and quickly. FFF adds material layer by layer, saving energy, costs, raw material costs, and waste. Nevertheless, the mechanical properties of the thermoplastic materials involved are low compared to traditional engineering materials. This paper deals with the manufacturing of composite material laminates obtained by the Markforged continuous filament fabrication (CFF) technique, using an innovative matrix infilled by carbon nanofibre (Onyx), a high-strength thermoplastic material with an excellent surface finish and high resistance to chemical agents. Three macro-categories of samples were manufactured using Onyx and continuous carbon fibre to evaluate the effect of the fibre on mechanical features of the novel composites and their influence on surface finishes. SEM (Scanning Electron Microscopy) analysis and acquisition of roughness profile by a confocal lens were conducted. Tensile and compression tests, thermogravimetric analysis and calorimetric analysis using a DSC (differential scanning calorimeter) were carried out on all specimen types to evaluate the influence of the process parameters and layup configurations on the quality and mechanical behaviour of the 3D-printed samples.

scholarly journals A Multi-Criteria Assessment Strategy for 3D Printed Porous Polyetheretherketone (PEEK) Patient-Specific Implants for Orbital Wall Reconstruction

2021 ◽  
Vol 10 (16) ◽  
pp. 3563
Author(s):  
Neha Sharma ◽  
Dennis Welker ◽  
Soheila Aghlmandi ◽  
Michaela Maintz ◽  
Hans-Florian Zeilhofer ◽  
...  
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Fused Filament Fabrication ◽  
Decision Matrix ◽  
Maximum Deformation ◽  
Patient Specific Implants ◽  
High Durability ◽  
Orbital Wall ◽  
3D Printed

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient’s unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

scholarly journals Deterioration of the Mechanical Properties of FFF 3D-Printed PLA Structures

Inventions ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Asahi Yonezawa ◽  
Akira Yamada
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Test Piece ◽  
Tensile Tests ◽  
Poly Lactic Acid ◽  
Uniaxial Tensile ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Test Pieces ◽  
3D Printed

Poly(lactic acid) (PLA) is a biodegradable polymer material used for the fabrication of objects by fused filament fabrication (FFF) 3D printing. FFF 3D printing technology has been quickly spreading over the past few years. An FFF-3D-printed object is formed from melted polymer extruded from a nozzle layer-by-layer. The mechanical properties of the object, and the changes in those properties as the object degrades, differ from the properties and changes observed in bulk objects. In this study we evaluated FFF-3D-printed objects by uniaxial tensile tests and four-point flexural tests to characterize the changes of three mechanical properties, namely, the maximum stress, elastic modulus, and breaking energy. Eight types of test pieces printed directly by an FFF 3D printer using two scan patterns and two interior fill percentages (IFPs) were tested by the aforesaid methods. The test pieces were immersed in saline and kept in an incubator at 37 °C for 30, 60, or 90 days before the mechanical testing. The changes in the mechanical properties differed largely between the test piece types. In some of the test pieces, transient increases in strength were observed before the immersion degraded the strength. Several of the test piece types were found to have superior specific strength in the tests. The results obtained in this research will be helpful for the design of PLA structures fabricated by FFF 3D printing.

Atomic layer deposition of photoelectrocatalytic material on 3D-printed nanocarbon structures

2021 ◽  
Author(s):  
Siowwoon Ng ◽  
Raul Zazpe ◽  
Jhonatan Rodriguez-Pereira ◽  
Jan Michalička ◽  
Jan M. Macak ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Layer By Layer ◽  
Layer Deposition ◽  
System P ◽  
Layer Manufacturing ◽  
Conversion System ◽  
3D Printed ◽  
Energy Conversion System ◽  
Manufacturing Techniques

Combining two advanced layer-by-layer manufacturing techniques, low-temperature atomic layer deposition of MoS2 on a customizable 3D-printed nanocarbon surface, for photoelectrochemical energy conversion system.

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