Here is the abstract you requested from the medical_2019 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Precision material deposition with aerosol jet technology for medical devices|
|Keywords: Medical device fabrication, Additive manufacturing, Aerosol Jet|
|Modern devices for medical applications are often designed with added materials on traditional apparatuses, such as catheters, balloons, stents, etc., to expand their functionalities. Those apparatuses usually have flexible and complicated nonplanar shapes, posing a serious challenge to common additive- manufacturing technologies. With dense mist of microdroplets carried by a high-speed impinging jet at large standoff, the Aerosol Jet® direct- write system offers the unique capability of precision material deposition for producing fine-feature electronic, structural, as well as biological patterns onto almost any substrate of arbitrary shape . It can be used to print helical conductive wires on a catheter tip to attach a microcoil for procedures like MRI-guided interventions, magneto- inductive imaging, and so on. Enabled by a 5-axis motion system (for control of relative position of substrate and Aerosol Jet® deposition nozzle), full three-dimensional patterns of arbitrary shapes can be produced on an inflatable balloon with Aerosol Jet® printing for in vivo ablation, cauterization, sensing, neuro- stimulation, to name a few. Besides printing microelectronics, therapeutic drugs can also be deposited onto stent struts, balloons in a site-specific fashion with superior resolutions to fabricate most effective drug-eluting stents  and drug-coated balloons for vascular disease treatments. For many applications, the deposited ink materials on designated locations per design intent must be solidified by removing solvents and, for printed microelectronics, must have conductive inks metallized by sintering while maintaining adequate adhesion, to yield final product with desired functionalities. Most conductive inks, consisting of metal nanoparticles or flakes, require sintering at a temperature above 150oC for yielding adequate conductivity; if placed in an oven for sintering, it may cause thermal damage to the polymer materials in catheters and balloons with Tg below the sintering temperature. In this presentation, we will discuss the principles and challenges in formulating processable inks for effective Aerosol Jet® printing as well as subsequent postprocessing, while showcasing the precision material deposition capabilities of Aerosol Jet® system for fabricating advanced medical devices. In principle, any atomizable ink material can be printed with the Aerosol Jet® system, but not all materials can be easily made atomizable. Moreover, the print quality such as line edge cleanliness can significantly influenced by ink rheology which involves solvent volatility, solids loading, and so on so forth. We will also discuss some recent development in advanced sintering techniques (such as using localized laser heating  or so) for metallizing conductive inks that consist of metal nanoparticles or flakes, among other material forms on temperature-sensitive substrates.|
|James Q. Feng, Principal Engineer
St. Paul, Minnesota