Wideband Ku-band antennas using multi-layer direct digital manufacturing

Author(s):  
Merve Kacar ◽  
Casey Perkowski ◽  
Paul Deffenbaugh ◽  
Janice Booth ◽  
Gokhan Mumcu ◽  
...  
2018 ◽  
pp. 181-194
Author(s):  
PHF Cavasso ◽  
NW Paschoalinoto ◽  
C Lazareti ◽  
D Gregório ◽  
DOT Bruno

O estudo se desenvolveu por meio da fabricação e posterior ensaio de corpos de prova confeccionados por meio de Direct Digital Manufacturing (DDM), usinagem de placas extrudadas e injeção de polímeros. Um comparativo das propriedades mecânicas obtidas pelos ensaios de tração foi realizada. A avaliação das aplicações de peças DDM, especialmente por se tratar de uma tecnologia relativamente jovem e que ainda não tem todo seu potencial explorado, foi o que motivou a realização desse trabalho. Cada um dos três processos avaliados apresentou particularidades. Os ensaios de peças usinadas e injetadas apresentaram resultados bem característicos, sendo o material usinado mais resistivo à forças trativas do que o material injetado. As peças fabricadas por DDM se mostraram tão eficientes quanto à injeção no ensaio de tração.


Author(s):  
Aamer Nazir ◽  
Jeng-Ywan Jeng

The primary concern of the Industry 4.0 is the direct digital manufacturing of customized products on demand at high production speed, high accuracy with functional material property. Although the unique capabilities of existing additive manufacturing technologies make it suitable for direct digital manufacturing, there are numerous limitations which include low printing speed, less accuracy and repeatability, and a limited selection of materials for a particular application. Therefore, a high-speed additive manufacturing approach is proposed in this paper, that is capable of achieving high speed of production, high accuracy, and surface finish, and functional material property. For better understanding, authors describe those additive manufacturing technologies that are capable of achieving the aforementioned characteristics. For validation, samples of various dimensions were 3D printed on a selective laser sintering and a high-speed multijet fusion 3D printer. The results were compared in the context of printing speed, surface roughness (Ra), and hardness of printed parts. Results revealed that the multijet fusion process is significantly faster than its counterpart while sacrificing Ra to some extent but the hardness of printed parts is not changed significantly. The selective laser sintering-printed samples had a 15% lower Ra compared with multijet fusion samples. The results also revealed that the multijet fusion process might be able to print composite/multi-materials; however, more research needs to be done.


2015 ◽  
Vol 107 ◽  
pp. 615-625 ◽  
Author(s):  
Danfang Chen ◽  
Steffen Heyer ◽  
Suphunnika Ibbotson ◽  
Konstantinos Salonitis ◽  
Jón Garðar Steingrímsson ◽  
...  

2016 ◽  
Vol 82 ◽  
pp. 82-94 ◽  
Author(s):  
Jouni Lyly-Yrjänäinen ◽  
Jan Holmström ◽  
Mats I. Johansson ◽  
Petri Suomala

Author(s):  
David N. Kordonowy ◽  
Sydney A. Giblin

This paper describes how direct digital manufacturing mechanical properties can be analytically estimated for structural use and the associated analytical and test methods used in the design and fabrication of airframes manufactured using additive manufacturing. Complex shape structures, which are now possible using additive manufacturing, and their associated mechanical properties can be predicted in order to allow operationally safe and highly predictive structures to be fabricated. Direct digital manufacturing allows for much greater flexibility and control over the design of airframes, leading to more structurally efficient and capable airframes. These advantages are revealed by application of direct digital manufacturing methods on a series of fixed wing subsonic transport concept wind tunnel scale models that are carried out as a part of the NASA N+3 program, which is paving the way for next generation aircraft that are highly fuel efficient, low-noise, and low-emission. Verification of these methods through test shows excellent correlation that provides reliability in complex sparse filled additive manufacturing design. The outcome of this is a knowledge base, which can then be applied to a system in operation. The combined potential of a flexible manufacturing system and proven predictive analysis tools shorten development time and expand the opportunities for mass customization. These combined benefits enable industry to fabricate affordable highly optimized custom products while concurrently reducing the cycle times required to field new products.


Author(s):  
Ming C. Leu ◽  
Parthiban Delli

Traditional methods of producing dental bars for overdentures involve tedious and time-consuming operations that demand substantial human labor and demanding skills. Though there exist several CAD/CAM systems that have been developed for various dental restorations like bridges, crowns, etc., there exists no commercial CAD/CAM system at present for design and fabrication of dental restorations for missing multiple teeth. In the research described in the present paper, CAD models of dental bars for implant-retained dental restorations were used as input for three types of fabrication processes: rapid prototyping followed by investment casting, CNC milling, and direct digital manufacturing. Details of material and process combinations and results of comparing these three types of processes, including an analysis on dimensional accuracy, are discussed.


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