Date on Master's Thesis/Doctoral Dissertation

12-2021

Document Type

Master's Thesis

Degree Name

M.S.

Department

Electrical and Computer Engineering

Degree Program

Electrical Engineering, MS

Committee Chair

Popa, Dan

Committee Co-Chair (if applicable)

Walsh, Kevin

Committee Member

Walsh, Kevin

Committee Member

Naber, John

Committee Member

Druffel, Thad

Author's Keywords

robotics; additive manufacturing; printing; 3d

Abstract

Additive manufacturing has created countless new opportunities for fabrication of devices in the past few years. Advances in additive manufacturing continue to change the way that many devices are fabricated by simplifying processes and often lowering cost. Fused deposition modeling (FDM) is the most common form of 3D printing. It is a well-developed process that can print various plastic materials into three-dimensional structures. This technology is used in a lot of industries for rapid prototyping and sometimes small batch manufacturing. It is very inexpensive, and a prototype can be created in a few hours, rather than days. This is useful for testing dimensions of designs without wasting time and money. Recently, a new form of additive manufacturing was developed known as aerosol jet printing (AJP). This process uses a specially developed ink with a low viscosity to print a wide range of metals and polymers. These printers work by atomizing the ink into a mist that is pushed out of a nozzle into a focused beam. This beam deposits material on the substrate at a standoff distance of 3-5 mm. Since this is a non-contact printing process, many non-planar surfaces can be printed on quite easily. AJP also offers very small feature sizes as low as 30 µm. It is useful for printing conductive traces and printing on unique surfaces. These printed traces often need some form of post processing to fully cure the ink and remove any solvent. For metals such as silver, this post processing removes solvent, increases conductivity, and increases adhesion. Methods for post processing include using an oven, intense pulse light (IPL), or a laser that follows the traces as they are printed. Of these methods, the IPL offers the greatest flexibility because it can cure a larger area than the laser and only takes a few seconds compared to hours in an oven. In this thesis, these two types of additive manufacturing processes, FDM and AJP, are explored, developed, and integrated with robotic manipulators in a custom system called the “Nexus”. By integrating these processes with robotic manipulators, these processes can be automated and combined to create unique processes and streamlined fabrication. The third chapter covers the development of the AJP printing and curing processes and integration with the Nexus system as well as some example devices such as a strain gauge. The fourth chapter goes over how a custom FDM module was integrated into the Nexus system and how material extrusion is synchronized with the motion component. Finally, in the second part of the fourth chapter, an FDM 3D printer is designed and fabricated as an end effector for a 6DOF robotic arm to be used in the Nexus system. To control these processes, G-Code is used to tell the machines the correct path to take. Methods for generating 5-axis G-Code are suggested to enable non-planar printing in the future.

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