08/16/2022
By Sokny Long

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a doctoral dissertation proposal defense by Karun Kalia on “In-situ foam 3D printing of thermoplastics using material extrusion additive manufacturing."

Ph.D. Candidate: Karun Kalia
Proposal Defense Date: Tuesday, August 30, 2022
Time: 8 to 10 a.m. EST
Location: ETIC-445 and virtual via zoom. Those interested in attending should contact karun_kalia@student.uml.edu and committee advisor amir_ameli@uml.edu at least 24 hours prior to the defense to request access to the meeting.

Committee Chair: Amir Ameli, Assistant Professor, Plastics Engineering, University of Massachusetts Lowell

Committee Members:

  • David O Kazmer, Professor, Plastics Engineering, University of Massachusetts Lowell
  • Jay Hoon Park, Assistant Professor, Plastics Engineering, University of Massachusetts Lowell

Brief Abstract:
Polymer foams have applications in thermal insulation, protection gear, vibration/damping/noise control, footwear, sports equipment, tissue engineering, etc. Cellular morphologies inside foams can be created using physical or chemical blowing agent as well as incorporation of thermally expandable microspheres (TEMs). Successful Integration of foaming and 3D-printing processes could offer several advantages: a) low material usage, b) microstructure control, c) shrinkage and inter-bead void mitigation in 3d-printed parts and, and d) more design freedom. However, there are limited reports on foam 3D printing processes. Here, a facile manufacturing method to enable the in-situ foam 3D printing of thermoplastic materials is being explored. The first phase of the study includes material formulation and process design exploring various PLA grades that can suppress the expansion during filament fabrication process. It also includes the characterization of mechanical, thermal and microstructure evolution of foamed 3D-printed parts w.r.t various TEM loadings. The second phase includes process-structure-property relationship of foam 3D-printed parts. The effect of print process parameters towards in-situ foam 3D printing process is investigated in detail as there are certain key factors which control the expansion of the extruded beads. The expansion and cooling kinetics of the extrudate will ultimately control the cellular morphologies (inside the extrudate) as well as bulk density thereby, affecting the mechanical properties of printed foams. The third and fourth phase which are ongoing studies includes 3D printing of graded foams with commercial printers and custom printers with in-situ static mixer. Functionally graded structures provide enhancement in properties such as energy absorption, efficient use of material usage and customized design for applications such as knee pads, helmets, tissues, drug delivery, etc.

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