RAPID 2013

Direct Write Printed Materials & Electronics

Wednesday, June 12, 2013
10:00 a.m. – Noon

Printed Optics: Interactive Objects and Devices using Optically Clear Materials and Embedded Components
Eric Brockmeyer, Lab Associate, Disney Research Pittsburgh
Karl D.D. Willis, PhD, Principal Research Engineer, Autodesk

Additive manufacturing technology allows us to create unique, personalized products for consumers and experiences for guests of Disney parks, hotels, and resorts. We believe that the next generation of these products will enable us to integrate interactive display, sensing, and illumination elements. Our research using jetted additive manufacturing explores novel techniques for creating optical components and a variety of applications.

Our library of optical components includes: optical fiber-like 'light pipes', internal light reflectors using enclosed air pockets, micro lens arrays, and embedded opto-electronic components. We used an Objet Connex 260 and have developed techniques for routing light pipes, building overhanging geometry without support, and smoothing/finishing optical components while still in the machine. These techniques are used in a range of applications to guide light from displays onto arbitrarily shaped objects, to reflect light in 3D displays and lighting elements, and to embed opto-electronic components for touch sensing. We believe additive manufacturing of optical components will enable unique, personalized interactive objects for consumer products and experiences of the future.

 

Complete Electrical Assemblies Made with Additive Manufacturing: Medical Applications
Mario Urdaneta, PhD, Staff Scientist/Engineer, Weinberg Medical Physics

Additive manufacturing typically uses a single material type, whether it is plastic, metal, or ceramic, to make an entire part. Rapid prototyping parts that combine different materials (e.g., conductors and insulators as in an electrical motor) in a single process is not yet an option. We have developed methods to rapid prototype parts that combine electrical conductors and insulators for making MRI gradient and RF coils. The parts include wires, insulation, cooling lines, and supporting structures. Our primary motivation is rapid prototyping MRI wires (i.e., Litz-like wires), which must be woven in sophisticated patterns to reduce proximity and skin-effects that produce losses at high frequencies and currents (patent pending). Our additive manufacturing approach will bypass the months-long and nearly-artisanal process of winding a Litz wire. Using additive manufacturing we can make wires with very tight turns, leading to coils that take less space and enable the design of MRIs with non-traditional shapes (e.g., dental MRI).We anticipate that eventually additive manufacturing of conductors and insulating structures will revolutionize the manufacturing of many electromagnetic components, especially in high frequency applications (e.g., hybrid cars).

 

Fabrication and Characterization of 3D Printed Compliant Tactile Sensors
Morteza Vatani, PhD Candidate, The University of Akron
Erik Engeberg, Assistant Professor, The University of Akron

Additive manufacturing technology with a direct-write conductive material is one promising approach to produce compliant tactile sensors. In this work, a multi-layer compliant tactile sensor was developed using a hybrid manufacturing process with an existing projection micro-stereolithography and micro-dispensing process. The sensor was designed to detect changes in resistance as it is deformed. A compliant skin structure was built layer-by-layer using a stretchable photopolymer in the micro-stereolithography system to cover the conductive elements. These sensing elements were created within the skin material by the micro-dispensing of a compliant conductive material during the microstereolithography process. The fabricated tactile sensor consists of two layers of sensing elements within the skin structure; there are eight stretchable straight wires in each layer. The wires in the second layer were orthogonally placed atop the first layer so that the sensor can detect various external forces/motions in two dimensions. To introduce conductivity, carbon nanotubes were dispersed in the stretchable photopolymer. The fabricated sensor was characterized by several experiments such as position, 2D pattern, direction, and slip/roll motion detection. Finally, it is concluded that the tactile sensor using the hybrid manufacturing method and materials is promising for various applications such as robotics, prosthetics, and wearable electronics.

 

Capability Assessment of Combining 3D Printing (FDM) and Printed Electronics (Aerosol Jet) Processes to Create Fully Printed Functionalized Devices
Amos Breyfogle, DDM-Application Engineer, Stratasys
Ken Vartanian, Director of Marketing, Optomec

The need to reduce the size, weight, costs and cycle times while also increasing functionality of highly integrated systems is a design requirement for many consumer and military product development programs. To date, additive manufacturing has demonstrated new ways to produce complex physical structures that reduce dependencies on tooling and traditional manufacturing methods. However, industry has identified that further benefits can be obtained through the integration of printed electronic circuitry and components into additive manufactured structures. This technology integration furthers additive manufacturing, with the resulting fully functionalized devices demonstrating the same benefits witnessed to date with additive manufactured structures, but to a new level.

Stratasys, Optomec, and Aurora Flight Sciences collaborated on a project to demonstrate how FDM and Aerosol Jet could be combined to produce typical electrical components (antenna, strain gauge, power circuit, and signal circuit) directly on the surface of 3D Printed wing structures. The exercise was a path finder to understand the capabilities of the combined technologies and the integration challenges. The results were very positive and demonstrated that the two technologies are compatible and can support immediate applications. Additional work is required to assess issues such as design rules, interface requirements, performance/lifecycle expectations, and supportability methods.


1:00 p.m. – 3:30 p.m.

Direct-Write and Printed Electronics in Aerospace
Joseph A. Marshall IV, Structural Designer, Boeing Research & Technology

Airplanes, satellites, and military systems all have a need for direct-write and printed electronics. The application space is very large and includes replacing current systems, improving current systems, or enabling entirely new capabilities. The needs range from wires, sensors, antennas, lighting, and more. But the challenging lifetime demands and requirements mean that the industry must develop very robust products. Boeing currently uses direct-write technology on the 747-8 and is investigation various other applications. There are currently holes in the development path of direct-write electronics which need to be addressed, including connectors, part size limitations, substrate materials, corrosion, and more.

 

Direct Write Printing of Sensors, Antennas & Circuitry
Jeff Brogan, PhD, CEO, MesoScribe Technologies, Inc.

MesoScribe Technologies specializes in materials processing based on its proprietary Direct Write Thermal Spray (DWTS) technology. This additive manufacturing process deposits materials in fine feature patterns producing sensors, antennas, and trace patterns using robotic 7-axis automation. A wide range of materials can be deposited including high quality copper conductors, ceramic dielectrics and capacitors, sensor alloys, precious metals, and semiconductors. The process is compatible with most substrate/component materials including polymer laminates, fiber-filled composites, and metallic structures. DWTS is currently used in the construction of aerospace components providing embedded circuitry as well as in high temperature propulsion systems providing diagnostic sensors (temperature, heat flux, strain) for structural health monitoring. In addition, MesoScribe has demonstrated the integration of UHF/VHF/L-Band antennas into air vehicle components and other military assets for advanced communication and signals intelligence. This presentation will summarize the latest advances in Direct Write Thermal Spray technology including material printing capabilities and high temperature sensor performance. DWTS has a significant role in the future of manufacturing, influencing product design to reduce costs while enhancing component functionality.

 

Pulsed Photonic Curing of Printed Functional Materials
Denis Cormier, Earl W. Brinkman Professor, Industrial and Systems Testing, Rochester Institute of Technology
Stan Farnsworth, Vice President of Marketing, NovaCentrix

The growing interest in hybrid processes that integrate electronics within additively manufactured parts can present significant challenges when the materials involved have significantly different melting/curing temperatures. Photonic curing has been used to rapidly heat printed inks and functional films to temperatures in excess of 1000°C on low-temperature substrates such as polymers and paper. It is therefore very well suited for use within hybrid multi-material AM processes. This talk will begin with an overview the process as well as a discussion of its strengths and limitations. The talk will then provide examples of high temperature functional materials that have been printed on polymer AM part surfaces and then photonically cured. The talk will conclude with a discussion of practical lessons learned.

 

3D Structural Electronics Fabrication Using Fused Deposition Modeling and Direct-Write Microdispensing
David Espalin, Graduate Research Associate, University of Texas at El Paso (W.M. Keck Center for 3D Innovation)

AM-fabricated unmanned aerial vehicles (UAVs) with integrated or printed electronics offer 3D design and electronic packaging flexibility that may facilitate UAV multi-role performance (i.e., reconnaissance, combat, and logistics) and as such have received much attention in the AM community as of late. Fundamentally, the advancement of 3D structural electronics using AM partly hinges on effectively interconnecting electronic components. In this particular case, the dispensing of conductive inks on FDM-produced surfaces presented several challenges including those related to wetting, electrical shorting between interconnections, and unintentional ink spreading throughout the part. As a solution to some of these issues, interconnection channels were used to confine or retain inks at the desired locations and prevent electrical shorting or ink spreading. Additionally, interconnection channels produced using micromachining achieved micro-scale features. Through this work, it was determined that FDM processing parameters and machining depths influenced successful electrical interconnection, which in the end, could be used to produce functional electronic systems using FDM.

 

RF Printed Circuit Structures using a Commercially Available Direct Print Tool
Ken Church, PhD, President, nScrypt Inc.

The mechanical segment of 3D printing has penetrated the manufacturing barrier, but the electrical segment has not. It is clear that mechanical structures are more mature than their electrical counter parts, but for the electrical segment to mature it must accomplish what the mechanical structures have accomplished; perform at a level that meets or exceeds state of the art. 3D electronic structures that have unique shape but inferior performance will be novel but not pervasive. To address the electrical performance issue it is imperative to involve electrical experts in 3D printing. A number of companies and universities are working on 3D electronic devices and this will provide a foundation for future products, but more is needed to make this a viable solution for true printed circuits. nScrypt sells commercial tools for the electronic industry and has recently added an nScrypt Fused Deposition (nFD) Pump on their micro-dispensing platform. 3D printing of next generation printed circuit structures has the potential to penetrate an existing printed circuit boards market; a commercially available 3D Printing tool can make this viable. nScrypt and the University of South Florida have teamed up to utilize this tool and work in the more challenging RF regime of printed electronics. Multi bit RF phase shifters are challenging for any fabrication process and 3D Printing these can show improvement in ruggedness and durability without degrading the performance. This has implications that reach into many industries, including the Department of Defense. In addition to the DoD, the printed circuit boards market for consumer products is in excess of $50B annually. For these industries to embrace the 3D printing approach the tools must be commercially available and supported and the end products must achieve or surpass state of the art. We will demonstrate the first commercially available tool with combined heterogeneous capability of plastics and metals for electronic applications and specifically RF electronics.