Rapid prototyping of multi-scale biomedical microdevices by combining additive manufacturing technologies

AbstractAdditive Manufacturing technologies are based on a layer-by-layer build-up. This offers the possibility to design complex geometries or to integrate functionalities in the part. Nevertheless, limitations given by the manufacturing process apply to the geometric design freedom. These limitations are often unknown due to a lack of knowledge of the cause-effect relationships of the process. Currently, this leads to many iterations until the final part fulfils its functionality. Particularly for small batch sizes, producing the part at the first attempt is very important. In this study, a structured approach to reduce the design iterations is presented. Therefore, the cause-effect relationships are systematically established and analysed in detail. Based on this knowledge, design guidelines can be derived. These guidelines consider process limitations and help to reduce the iterations for the final part production. In order to illustrate the approach, the spare parts production via laser powder bed fusion is used as an example.

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Adhesion Studies during Generative Hybridization of Textile-Reinforced Thermoplastic Composites via Additive Manufacturing

Materials ◽

10.3390/ma14143888 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3888

Author(s):

Johanna Maier ◽

Christian Vogel ◽

Tobias Lebelt ◽

Vinzenz Geske ◽

Thomas Behnisch ◽

...

Keyword(s):

Additive Manufacturing ◽

Polyamide 6 ◽

Thermoplastic Composites ◽

Efficient Production ◽

Angle Measurements ◽

Small Series ◽

Contact Angle Measurements ◽

Static Tensile ◽

Pre Treatment ◽

Manufacturing Technologies

Generative hybridization enables the efficient production of lightweight structures by combining classic manufacturing processes with additive manufacturing technologies. This type of functionalization process allows components with high geometric complexity and high mechanical properties to be produced efficiently in small series without the need for additional molds. In this study, hybrid specimens were generated by additively depositing PA6 (polyamide 6) via fused layer modeling (FLM) onto continuous woven fiber GF/PA6 (glass fiber/polyamide 6) flat preforms. Specifically, the effects of surface pre-treatment and process-induced surface interactions were investigated using optical microscopy for contact angle measurements as well as laser profilometry and thermal analytics. The bonding characteristic at the interface was evaluated via quasi-static tensile pull-off tests. Results indicate that both the bond strength and corresponding failure type vary with pre-treatment settings and process parameters during generative hybridization. It is shown that both the base substrate temperature and the FLM nozzle distance have a significant influence on the adhesive tensile strength. In particular, it can be seen that surface activation by plasma can significantly improve the specific adhesion in generative hybridization.

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MODEL-BASED DESIGN OF AM COMPONENTS TO ENABLE DECENTRALIZED DIGITAL MANUFACTURING SYSTEMS

Proceedings of the Design Society ◽

10.1017/pds.2021.474 ◽

2021 ◽

Vol 1 ◽

pp. 2127-2136

Author(s):

Olivia Borgue ◽

John Stavridis ◽

Tomas Vannucci ◽

Panagiotis Stavropoulos ◽

Harry Bikas ◽

...

Keyword(s):

Additive Manufacturing ◽

Manufacturing Systems ◽

Production Systems ◽

Data Generation ◽

Production Networks ◽

Model Based ◽

Manufacturing Technologies ◽

Am Processes ◽

Final Consumer

AbstractAdditive manufacturing (AM) is a versatile technology that could add flexibility in manufacturing processes, whether implemented alone or along other technologies. This technology enables on-demand production and decentralized production networks, as production facilities can be located around the world to manufacture products closer to the final consumer (decentralized manufacturing). However, the wide adoption of additive manufacturing technologies is hindered by the lack of experience on its implementation, the lack of repeatability among different manufacturers and a lack of integrated production systems. The later, hinders the traceability and quality assurance of printed components and limits the understanding and data generation of the AM processes and parameters. In this article, a design strategy is proposed to integrate the different phases of the development process into a model-based design platform for decentralized manufacturing. This platform is aimed at facilitating data traceability and product repeatability among different AM machines. The strategy is illustrated with a case study where a car steering knuckle is manufactured in three different facilities in Sweden and Italy.

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Influence of Deposition Patterns on Distortion of H13 Steel by Wire-Arc Additive Manufacturing

Metals ◽

10.3390/met11030485 ◽

2021 ◽

Vol 11 (3) ◽

pp. 485

Author(s):

Xufeng Li ◽

Jian Lin ◽

Zhidong Xia ◽

Yongqiang Zhang ◽

Hanguang Fu

Keyword(s):

Additive Manufacturing ◽

Temperature History ◽

H13 Steel ◽

Deposition Patterns ◽

Field Distortion ◽

Set Up ◽

Manufacturing Technologies ◽

Inherent Strain ◽

Inherent Strain Method ◽

Wire Arc Additive Manufacturing

Wire-arc additive manufacturing (WAAM) has been considered as one of the potential additive-manufacturing technologies to fabricate large components. However, its industrial application is still limited by the existence of stress and distortion. During the process of WAAM, the scanning pattern has an important influence on the temperature field, distortion and final quality of the part. Four kinds of deposition patterns, including sequence, symmetry, in–out and out–in, were designed to deposit H13 steel in this study. An in situ measurement system was set up to record the temperature history and the progress of accumulated distortion of the parts during deposition. An S value was proposed to evaluate the distortion of the substrate. It was shown that the distortion of the part deposited by sequence was significantly larger than those of other parts. The distortion deposited by the out–in pattern decreased by 68.6% compared with sequence. The inherent strain method and strain parameter were introduced to expose the mechanism of distortion reduction caused by pattern variation.

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A review on current additive manufacturing technologies and materials used for fabrication of metal-ceramic fixed dental prosthesis

Journal of Adhesion Science and Technology ◽

10.1080/01694243.2021.1899699 ◽

2021 ◽

pp. 1-18

Author(s):

Henning Hesse ◽

Mutlu Özcan

Keyword(s):

Additive Manufacturing ◽

Dental Prosthesis ◽

Fixed Dental Prosthesis ◽

Metal Ceramic ◽

Materials Used ◽

Manufacturing Technologies

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3D Printed Masks for Powders and Viruses Safety Protection Using Food Grade Polymers: Empirical Tests

Polymers ◽

10.3390/polym13040617 ◽

2021 ◽

Vol 13 (4) ◽

pp. 617

Author(s):

Ruben Foresti ◽

Benedetta Ghezzi ◽

Matteo Vettori ◽

Lorenzo Bergonzi ◽

Silvia Attolino ◽

...

Keyword(s):

Surface Roughness ◽

Additive Manufacturing ◽

Material Selection ◽

Mechanical Resistance ◽

Biological Safety ◽

Fused Deposition ◽

Industrial Grade ◽

Safety Protection ◽

3D Printed ◽

Manufacturing Technologies

The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS-COV-2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet-based precision extrusion deposition (db-PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home-grade printing equipment have similar performances compared to the industrial-grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post-processing phases essential to assure human safety in the production of 3D printed custom medical devices.

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