IMPROVING QUALITY OF MULTI-FUNCTIONAL STRUCTURES CREATED VIA MATERIAL EXTRUSION ADDITIVE MANUFACTURING

Open Access
Author:
Sinha, Swapnil
Graduate Program:
Engineering Design
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 20, 2017
Committee Members:
  • Nicholas A. Meisel, Thesis Advisor
  • Sven G. Bilen, Committee Member
Keywords:
  • Design for 'X'
  • Embedding
  • Multi-functionality
  • CubeSat
  • Manufacturing
  • Resistive Heating
  • Material Extrusion
  • Internet of Things
  • Polymer
  • Anisotropy
  • Print Process Interruption
  • Design for Additive Manufacturing
Abstract:
This work is motivated by Additive Manufacturing’s (AM) ability to create multi-functional components via in-situ embedding. The layer-by-layer material addition approach gives designers access to the entire volume of a part, enabling embedding of foreign, multi-functional components in printed parts. The typical embedding process for AM involves i) designing the cavity for the embedded component, ii) interrupting the build process when the top layer of the cavity is reached, iii) manually inserting the foreign component, and iv) resuming the build process. While build process interruption during printing is a requirement for embedding, interruptions can also be caused by power outages, system errors, or material shortages. However, the influence of this interruption on AM manufactured parts is not well understood. This thesis discusses the effects of the embedding process on the material properties of material extrusion parts by addressing two different factors: i) the time duration of process interruption in a print and ii) the material transition between the embedded component and the build material when resuming the print after embedding. The information on how these two factors influence material properties can provide crucial information for designers to make design and process decisions for embedding in AM. For this purpose, the tensile strength of 3D-printed specimens with embedded elements were tested in this study, subjected to different pause time intervals, and with or without shape converters. In order to counteract any weakness due to pausing, specimens in additional testing were reheated at the paused layer immediately prior to resuming, and tensile strengths were analyzed to observe any improvements. The findings from these investigations are used as design guidelines for redesign and manufacturing of a multifunctional cross brace structure of a three unit CubeSat.