01/18/2021
By Sokny Long

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a doctoral proposal defense by Austin Colon on “Modeling and Control of Process Dynamics in Fused Filament Fabrication.”

PhD Candidate: Austin Colon
Defense Date: Friday, Jan. 29, 2021
Time: 1 to 2:30 p.m. EST
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Austin_Colon@student.uml.edu, and committee advisor, David_Kazmer@uml.edu, at least 24 hours prior to the defense to request access to the meeting.


Committee Chair (Advisor): Professor David Kazmer, Plastics Engineering, University of Massachusetts Lowell

Committee Members:

  • Professor Amy Peterson, Plastics Engineering, University of Massachusetts Lowell
  • Professor Stephen Johnston, Plastics Engineering, University of Massachusetts Lowell
  • Professor Jay Park, Plastics Engineering, University of Massachusetts Lowell

Abstract:
In recent years, fused filament fabrication (FFF) has taken the largest market share in the additive manufacturing space, providing users with the ability to manufacture complex geometries from a wide range of materials, relative to other additive processes, using low-cost equipment. The research proposed aims to improve the part-to-part, and file-to-part, consistency of this process by focusing on three areas. First, isothermal conditions are commonly assumed, though they are not typically achieved at higher flow rates due to constraints rooted in hot end design. Nonisothermal modeling and experiments varying hot end design aspects are proposed to study and optimize melting. To enhance process observability, the second area focuses on instrumenting a FFF printer to monitor extruder motor torque, and the current provided to the motor. The direct motor torque measurements will allow for an enhanced understanding of the FFF process and will be leveraged as validation for indirect melt pressure prediction via motor current. Lastly, transient compressibility effects have been observed in FFF, leading to part defects such as under-extrusion, so a control scheme will be incorporated into the FFF printer’s controller to allow for ‘Gcode’ corrections that compensate for these effects. The proposed research explores the potential of novel hot end and nozzle designs for improved melting, stepper motor monitoring to correlate input current to nozzle pressure, and compressibility compensation via re-processing the Gcode commands within the FFF printer’s controller.

All interested students and faculty members are invited to attend the online defense via remote access.