scholarly journals Laser curing of silver-based conductive inks for in situ 3D structural electronics fabrication in stereolithography

2014 ◽  
Vol 214 (9) ◽  
pp. 1935-1945 ◽  
Author(s):  
Amit J. Lopes ◽  
In Hwan Lee ◽  
Eric MacDonald ◽  
Rolando Quintana ◽  
Ryan Wicker
Keyword(s):  
Conductive Inks ◽  
Structural Electronics ◽  
3D Structural Electronics ◽  
Laser Curing

Ohmic Curing of Three-Dimensional Printed Silver Interconnects for Structural Electronics

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
David A. Roberson ◽  
Ryan B. Wicker ◽  
Eric MacDonald
Keyword(s):  
Selection Process ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Substrate Material ◽  
Direct Write ◽  
Conductive Inks ◽  
Structural Electronics ◽  
3D Structural Electronics ◽  
Substrate Resistance ◽  
Polymeric Substrates

Ohmic curing was utilized as a method to improve the conductivity of three-dimensional (3D) interconnects printed from silver-loaded conductive inks and pastes. The goal was to increase conductivity of the conductive path without inducing damage to the substrate. The 3D via/interconnect structure was routed within 3D polymeric substrates and had external and internal sections. The 3D structures were created by the additive manufacturing (AM) process of stereolithography (SL) and were designed to replicate manufacturing situations which are common in the fabrication of 3D structural electronics that involve a combination of AM and direct write (DW) processing steps. The photocurable resins the 3D substrates were made of possessed glass transition temperatures of 75 °C and 42 °C meaning that a nonthermal method to increase the conductivity of the printed traces was needed as the conductive inks tested in this study required oven cure temperatures greater than 100 °C to perform properly. Ohmic curing was shown to decrease the measured resistance of the via/interconnect structure without harming the substrate. Substrate damage was observed on thermally cured samples and was characterized by discoloration and scaling of the substrate. Resistance measurements of the via/interconnect structures revealed samples cured by the ohmic curing process performed equal or better than samples subjected to thermal curing. The work presented here demonstrates a method to overcome the thermal cure temperature limitations of polymeric substrates imposed on the processing parameters of conductive inks during the fabrication of 3D structural electronics and presents an example of overcoming a manufacturing process problem associated with this emerging technology. An ink selection process involving characterization of the compatibility of inks with the substrate material and the use of different inks for the via and interconnect sections was also discussed.

Development of Direct Printing/Curing Process for 3D Structural Electronics

2013 ◽  
Author(s):  
Yanfeng Lu ◽  
Morteza Vatani ◽  
Ho-Chan Kim ◽  
Rae-Chan Lee ◽  
Jae-Won Choi
Keyword(s):  
Tool Path ◽  
Electronic Circuit ◽  
3D Structure ◽  
Radiation Energy ◽  
New Paradigm ◽  
Direct Printing ◽  
Pick And Place ◽  
Structural Electronics ◽  
3D Structural Electronics ◽  
Electrical Components

3D structural electronics is a new paradigm in fabricating electronics with high design complexity. Basically, manufacturing of 3D structural electronics consists of several processes: structure building, wire creation, and pick-and-place of electrical components. In this work, a 3D structure was built in a commercial AM machine, and conductive wires were created on the 3D structure with a predetermined design of an electronic circuit. Generally, 2D wire paths are projected to a 3D surface, and a tool path for the wire is generated in advance. And a direct printing device follows the tool path to draw the conductive wires on the surface, while a direct curing device simultaneously hardens the created wires using thermal/radiation energy. This direct printing/curing device was developed by combining a micro-dispensing device and a light focusing module installed in a motorized xyz stage. Several experiments were accomplished using photocrosslinkable materials filled with carbon nanotubes (CNTs). Finally, a 3D electronics prototype was fabricated to show the compelling evidence that the suggested manufacturing methods and materials would be promising in manufacturing 3D structural electronics.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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