The next trend in 3D printing appears to be incorporating electronics into the part during the printing process, i.e., without stopping the printing operation. Optomec was one of the first to do so. Now three students from Stanford University, CA, have developed a unique take on printing electronics into a part.
Students Alex Jais, Manal Dia, and Rohan Maheshwari developed their print head plugin device, Rabbit Proto, as part of a design class project. The open source Rabbit Proto prints electronic ink on 3D printed surfaces, enabling you to print complex conductive traces. You can print both capacitive and conductive features. And it’s available now for pre-order, with shipments starting in July.
The print head add-on consists of a 10cc syringe-like extruder that deposits the special conductive ink. The add-on is compatible with all RepRap printers having a dual-extrusion board. However, the unit can be modified to adapt to other 3D printers. You can email the team directly or load a design up to GitHub, where the project source code, documentation, and example designs reside.
The three students have been working on developing conductive material and Bare Conductive ink for printing capacitive touch sensors. They have also done tests with silver filled silicon RTV, a more conductive but also more expensive material.
Rabbit Proto is available in three versions. The basic Rabbit Proto extruder costs $350 and comes with a Gauge 15 (1.371 mm) nozzle. The Super Rabbit model includes a 1.75mm filament extruder and a syringe extruder for $450. It is compatible with 1.75 mm ABS, PLA, and Nylon. The Rabbit 3D fully assembled printer, available for $2,499, is shipped ready to go
Optomec developed a high volume process. In one application, it 3D prints the antennas used in mobile devices. The 3D printer handles standard injection molded plastics, and through the Aerosol Jet technology digital process prints conformal antennas using conductive nanoparticle silver inks. The printing process accurately controls the location, geometry and thickness of the deposit and produces a smooth mirror like surface finish to insure optimum antenna performance. No plating or environmentally harmful materials are used in the process.
Mobile device antennas including LTE, NFC, GPS, Wifi, WLAN, and BT have been printed using the Aerosol Jet process and independently tested by a leading cell phone component supplier. Measured antenna performance is comparable to other production methods. The Aerosol Jet printing process is scalable – antennas can be printed on up to 4 cases simultaneously on a single machine. Machine throughput for a typical antenna pattern measuring ~300 mm2 averages 30,000 units per week.
Probably the most noted example is the aircraft wing with printed electronics. Common electronic materials including conductor, dielectric, resistor, and semiconductor inks can be processed to print conformal sensors, antennas, shielding and other active and passive components. Printing these electronic components directly on or inside the physical device eliminates the need for separate printed circuit boards, cabling and wiring thereby reducing weight and size while also simplifying the assembly process. Device performance can also be improved by eliminating protruding components such as antenna thereby reducing aerodynamic drag.
In this example, the Aerosol Jet system was used to print a conformal sensor, antenna, and power and signal circuitry directly onto the wing of a UAV model. The wing itself was 3D printed with the Stratasys. The electrical and sensor designs were provided by Aurora Flight Sciences, a supplier of UAVs.
Leslie Langnau
llangnau@wtwhmedia.com
