Additive Manufacturing Methodology Research Articles

A novel path planning methodology for extrusion-based additive manufacturing of thin-walled parts

Extrusion-based layered deposition is one of the widely used additive manufacturing (AM) technologies due to its flexibility and capability in producing prototypes without geometrical complexity limitations. One of the most important steps in determining the part quality and build time is the path planning, where the trajectory for guiding the extruder is defined by various aspects prior to actual deposition. In this paper, a novel methodology is presented to generate the deposition path for the extrusion-based AM of thin-walled parts, which is difficult to obtain desirable deposition quality using general filling paths. A wavy path pattern is adopted to fill the long and narrow cross-sections that are obtained from the slicing procedure of the thin-walled parts. This novel filling pattern can bring in better deposition results and has more excellence in enhancing the efficiency. The algorithms are proposed for the generation of wavy paths at first. Then, several implementations and optimisation methods are proposed to address some issues and extend its application. Finally, two cases are used to verify the developed methodology, and the comparison analysis demonstrates its evident advantages over traditional filling path in the fabrication efficiency for the extrusion-based additive fabrication of thin-walled objects.

Methodology for Image-driven High-resolution Additive Manufacturing Using Discretized Data Set

Additive manufacturing of patient-specific biomedical devices from 3D medical scans involves several steps of conversion which can introduce error into the final part. This is particularly critical to the fabrication of minute anatomical features, such as microvasculature. We show a direct conversion of the raw optical coherence tomography (OCT) volumetric data into photomasks in bitmap format, which streamlines the typical process steps used in 3D printing medical scans. OCT scans of rodent retinal microvasculature and projection microstereolithography are used to fabricate a solid vascular replica and a solid volume with hollow embedded microvessels.

An Additive Manufacturing Solution to Produce Big Green Parts from Tires and Recycled Plastics

Recycling is crucial for the conservation and improvement of the environment. The reduction of natural resource exploration and recovery of waste are examples of actions to contribute to a sustainable development. Waste from end-of-life tires and undifferentiated plastics represents an environmental problem due to the very high number of tons of used tires and plastics produced, but with a high economic potential because their incorporation into high value-added products is an issue of utmost importance. The manufacturing technologies oriented to the increase in quality levels, functional advantages, structural and financial gains of the produced products are currently a hot topic in industry. Similarly, the use of additive manufacturing technologies, instead of conventional techniques, e.g. moulding to process materials obtained from waste recovery, is a great industrial challenge.In order to promote greater environmental responsibility and to present innovative solutions for the management and sustainable destination of used waste recovery from tires and undifferentiated plastics, a composite made from the blend of 60% of tire waste granulate and 40% of polypropylene (PP) recycled was tested with the final purpose of generating components with added value. Both waste recovery materials were used in the micronized state. The thermal and mechanical behaviours of the synthesized composite were studied through DSC/TGA analysis and tensile testing. The implementation of additive manufacturing methodologies to process the blends between used tires granulated with a high incorporation of wastes from undifferentiated plastics was also explored in this work in order to produce big green parts without mould needed, such as urban furniture.

Application of a Hybrid Additive Manufacturing Methodology to Produce a Metal/Polymer Customized Dental Implant

In this paper an integrated methodology for implants personalized manufacturing is presented. This methodology materializes the hybrid material implants manufacturing through the integration of two or more advanced Additive Manufacturing (AM) technologies. Furthermore, high strength biomechanical implants with optimized geometry and mass can be manufactured by biomimetic concepts application. The combination of polymers and ceramics or polymers and metal materials (or metal alloys) allows a significant leap in the development and production of a great diversity of components and applications. The combination of advanced additive manufacturing processes, e.g. the Selective Laser Melting (SLM) or Selective Laser Sintering (SLS) and the StereoLithography (SL), make possible the production of parts with almost unlimited geometric freedom and custom multimaterial. The manufacturing flexibility and the processing capacity of the different combinations of materials - metal/polymer - obtained from hybrid additive manufacturing systems - SLM/SL - are demonstrated here by the manufacture of a dental bridge implant.

A novel high-efficiency methodology for metal additive manufacturing

Metal additive manufacturing (AM) offers unrivalled design freedom with the ability to manufacture complex parts. However, the high capital costs and slow throughput printing have severely restricted its application. In this paper, a new metal AM process, referred to as the “metal fused-coating additive manufacturing (MFCAM)”, was developed for highly efficient metal parts production. This new process is the combination of metal fused-coating process and laser surface melting process. A two-dimensional numerical model was established to provide an insight into the primary thermo-physical phenomena occurring in the MFCAM process. Experiments of single-track formation were conducted using MFCAM to validate the feasibility of the proposed process. The good agreement between experimental and simulated results demonstrated the reasonableness of the established models.

Multiphasic constructs and cell sheet technology in the context of periodontal regeneration

Event Abstract Back to Event Multiphasic constructs and cell sheet technology in the context of periodontal regeneration Cedryck Vaquette1, Saso Ivanovski2 and Dietmar Werner Hutmacher1 1 Queensland University of Technology, Institute of Health and Biomedical Innovation, Australia 2 Griffith University, School of Dentistry and Oral Health, Menzies Health Institute Queensland, Australia Introduction: Periodontitis is a common chronic inflammatory disease that results in degradation of the supporting structures around teeth and in severe cases can lead to tooth loss. Current surgical treatments such as Guided Tissue Regeneration (GTR) are efficient at limiting the progression of the disease by controlling the inflammatory aspect of periodontitis but regeneration is not commonly achieved. Our groups have developed a tissue engineering strategy involving the utilisation of cell sheets combined with biphasic biomaterial scaffolds in order to enhance the regenerative capacity of GTR. The biphasic structures, composed of a bone and periodontal compartments, are specifically designed to recapitulate the highly organised and hierarchical architecture of the native periodontium composed of cementum, periodontal ligament, alveolar bone and gingival tissue. This paper provides an overview of the research we have performed in this area along with our latest advancements. Materials and Methods: Several generations of polycaprolactone (PCL) biphasic constructs were developed combining additive manufacturing methodologies such as Fused Deposition Modelling (FDM), solution electrospinning and Melt Electrospinning Writing (MEW). Our most recent research has resulted in the development of a fibre guiding scaffold manufactured by MEW for the bone compartment and by nanofabrication technologies for the creation aligned silk fibroin micro-channels for the periodontal compartment. Our constructs have been tested in vitro and in vivo into rodent and ovine models while testing several architectures and cell sources (gingival fibroblasts, periodontal ligament fibroblasts, and bone marrow mesenchymal stem cells). Results and Discussion: We have demonstrated that our biphasic scaffolds fulfilled the requirements for GTR; wound stabilisation, space maintenance and selective cell repopulation, and were capable of regenerating fraction or entire portion of the periodontium complex in a rodent ectopic model and in a surgically created periodontal one model. The presence of the cell sheets was also essential for the improved regeneration of the targeted organ. The incorporation of aligned channels into the biphasic scaffold design resulted in guiding the orientation of the newly formed periodontal ligament fibres. Conclusion: The development of multicompartment scaffolds for periodontal regeneration has been proven as an effective strategy when combined with cell delivery. Further to the delivery of cells, tissue guidance provided by topographical clues, is also essential and resulted in a physiologically relevant attachment of the newly formed periodontal fibres. Keywords: Regenerative Medicine, 3D scaffold, complex tissue orgnization, cell sheeting Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Combinatorial approaches to biomaterial design Citation: Vaquette C, Ivanovski S and Hutmacher D (2016). Multiphasic constructs and cell sheet technology in the context of periodontal regeneration. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00904 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Cedryck Vaquette Saso Ivanovski Dietmar Werner Hutmacher Google Cedryck Vaquette Saso Ivanovski Dietmar Werner Hutmacher Google Scholar Cedryck Vaquette Saso Ivanovski Dietmar Werner Hutmacher PubMed Cedryck Vaquette Saso Ivanovski Dietmar Werner Hutmacher Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A practical path planning methodology for wire and arc additive manufacturing of thin-walled structures

This paper presents a novel methodology to generate deposition paths for wire and arc additive manufacturing (WAAM). The medial axis transformation (MAT), which represents the skeleton of a given geometry, is firstly extracted to understand the geometry. Then a deposition path that is based on the MAT is efficiently generated. The resulting MAT-based path is able to entirely fill any given cross-sectional geometry without gaps. With the variation of step-over distance, material efficiency alters accordingly for both solid and thin-walled structures. It is found that thin-walled structures are more sensitive to step-over distance in terms of material efficiency. The optimal step-over distance corresponding to the maximum material efficiency can be achieved for various geometries, allowing the optimization of the deposition parameters. Five case studies of complex models including solid and thin-walled structures are used to test the developed methodology. Experimental comparison between the proposed MAT-based path patterns and the traditional contour path patterns demonstrate significant improved performance in terms of gap-free cross-sections. The proposed path planning strategy is shown to be particularly beneficial for WAAM of thin-walled structures. A novel path planning methodology based on the Medial Axis Transformation (MAT) of the geometry is proposed.Gap-free paths can be obtained for any arbitrarily shaped geometry.Relationships between step-over distance and material efficiency are analysed.Optimal step-over distances for different Additive Manufacturing (AM) systems are discussed.The proposed path planning strategy is particularly useful for wire and arc additive manufacturing of thin-walled structures.

A novel methodology of design for Additive Manufacturing applied to Additive Laser Manufacturing process

Nowadays, due to rapid prototyping processes improvements, a functional metal part can be built directly by Additive Manufacturing. It is now accepted that these new processes can increase productivity while enabling a mass and cost reduction and an increase of the parts functionality. However, the physical phenomena that occur during these processes have a strong impact on the quality of the produced parts. Especially, because the manufacturing paths used to produce the parts lead these physical phenomena, it is essential to considerate them right from the parts design stage. In this context, a new numerical chain based on a new design for Additive Manufacturing (DFAM) methodology is proposed in this paper, the new DFAM methodology being detailed; both design requirements and manufacturing specificities are taken into account. The corresponding numerical tools are detailed in the particular case of thin-walled metal parts manufactured by an Additive Laser Manufacturing (ALM) process.

New advances on tracheal stent manufacturing

Abstract Several complications, including tumors, can cause the obstruction of the trachea. To prevent from suffocation, tubular implants named stents are used. Commercially available stents are expensive and not anatomically adapted, and therefore big challenges need to be faced in order to improve them. This work presents several additive manufacturing methodologies to fabricate customized tracheal stents. Rapid tooling seems to be the best option. Two different molds were manufactured using open-source low-cost machines in order to reduce costs. In addition, a high speed machine was also used to fabricate another mold. The molds produced were poured either with a non-implantable medical grade platinum silicone or with an implantable medical grade liquid silicone rubber in order to obtain the final tailored tracheal stents. Finally, a mechanical behavioral test was performed with implantable medical grade liquid silicone rubber stents. The results showed an adequate Young Modulus suitable to favor the insertion and extraction of the stent from the human trachea. Future work is needed to fully study the tracheal stents manufacturing process and be able to introduce several important steps, such as the sterilization of the product and the certification of the entire process.