Discipline: Technology and Engineering
Subcategory: Computer Engineering
Room: Exhibit Hall A
Essence McClinton - North Carolina A&T State University
Co-Author(s): Dr. Carl A. Moore Jr., Florida A&M-Florida State University College of Engineering, FL; Brianna Wylie, Florida A&M-Florida State University College of Engineering, FL
3D printing is an additive manufacturing process that has an untold number of applications in fields as diverse as medical prostheses to military vehicle manufacturing not to mention its long term use in component prototyping. High resolution 3D printers are becoming indispensable in the creation of complex parts with smooth surfaces and intricate details. With the creation of robotic arm based printers, the 3D printing process can be improved in terms of flexibility and time‐efficiency, but with the potential trade‐off being lower resolution in some areas of the printer workspace. This study seeks to determine if it is possible to eliminate the resolution reduction of articulated arm based printers by coupling spherical continuously variable transmissions (SCVTs) to the robot’s arm joints. We have successfully applied SCVTs in the design of haptic interfaces and believe that they may be the key to improving the capability of articulated arm based printers. To investigate the effect of SCVTs on articulated arm based 3D print resolution we used MATLAB to print simulated 3D parts from printers with various joint configurations and stepper motor resolutions. Our simulated articulated arm printer was based on our 3‐axis Dexter robot. Dexter is a multipurpose dexterous machine with a 3 axis SCARA (Selective Compliance Assembly Robot Arm) configuration. In our tests we developed the kinematic equations that control the motion of Dexter’s end effector which is equipped with a standard 3D printer nozzle. We used these equations to compare the simulated prints of a standardized 3D model from Dexter with those from a traditional gantry style 3D printer like the MakerBot Replicator 2. We demonstrate that even with high stepper motor microstepping, the resolution of a stepper motor equipped SCARA configuration printer will lag far behind that of a gantry style printer. We next developed kinematic equations for a SCARA printer with two SCVTs coupled in parallel to one robot joint each. The resolution improvement of the simulated prints was dramatic, many times better than the previous SCARA simulations and as good as the gantry style printer. Moreover, unlike the original SCARA, the SCVT equipped model has a homogeneous resolution map meaning that the nozzle resolution is not a function its x‐y position on the build plate. These results indicate that the resolution improvement can be maintained wherever the nozzle moves. Through simulation we have shown that SCVTs should make it possible to create an articulated arm based 3D printer using stepper motors without negatively impacting nozzle resolution. These 3D printers will have the dexterity needed to improve both 3D printing flexibility and time‐efficiency. For future work, we anticipate building a SCARA based 3D printer with SCVT equipped joints. We are also interested in determining if the controller of SCVT equipped 3D printer will excel at printing curved line segments. References: Moore C, Peshkin M, Colgate E 1999 A Three Revolute Cobot Using CVTs in Parallel Proc. ASME Int. Mechanical Engineering Congress and Exposition. Nashville, TN. Frketic J, Psulkowski S, Sharp A, Dickens T 2017. Procedia Manufacturing 10. pp 1087‐96. Luo R and Tseng P Carving 2D image onto 3D curved surface using hybrid additive and subtractive 3D printing process 2017. Int. Conf. on Advanced Robotics and Intelligent Systems (ARIS). (Taipei) pp 40‐45. McQueen K, Darensbourg S, Moore C, Dickens T, Allen C Efficient path planning of secondary additive manufacturing operations 2018. Proc. 5th Int. Conf. Mechanical, Materials and Manufacturing (Orlando). MakerBot Replicator2 brochure, makerbot.com, 2019. Brokowski, M, et al. Toward improved CVTs: theoretical and experimental results (2002) ASME Int. Mechanical Engineering Congress Exposition. (New Orleans)
Funder Acknowledgement(s): I would like to acknowledge the RISE and MASS REU programs for funding this research project, as well as the National Science Foundation. I would also like to thank the administrators of the FSU AME Building for the use of the lab. A special thank you to Dr. Carl A. Moore Jr. and Brianna Wylie for their assistance on this research project.
Faculty Advisor: Dr. Carl A. Moore Jr., email@example.com
Role: In this research project, I was responsible for creating a code in MATLAB that would run through each line of our gcode, and plot the line segments of the object, layer by layer, as it would be physically 3D printed. I then used points from a single layer of my plot to run through a code, modified by myself, to plot the resolution of the SCARA robot at each individual point. I did this for our robot simulated with the standard transmission, as well as when it was simulated with CVTs. I then compared the graphs and presented my findings.