Utilizing a Design of Experiments Approach to Optimize the Processing Parameters for Extrusion-Based Rapid Prototyping of Bombyx Mori Silk.
prototyping is quickly making its way into every industry in the world. Its impact on
the speed and accuracy of manufacturing is undeniable. In recent years, many variations
of rapid prototyping have been utilized in the biomedical world as a means of
replicating geometries and mechanical properties to personalize prints for a person or
specific body part. As computer and soft... read moreware capabilities continue to develop and
accommodate for more printing parameters, rapid prototyping of biomaterials is becoming
increasingly more advanced and useful for in vitro and in vivo applications. The variety
of biomaterials that are being used is expanding and the use of live cells, in hydrogel
materials specifically, after or during the printing process is quickly emerging. The
combination of the mechanically attractive biomaterial, silk, and a sterile rapid
prototyping device can lead to significant advances in time and material usage for
biomedical applications. The aim of this thesis is to investigate the processing
parameters that impact manufacturing efficiency and quality during the rapid extrusion
of silk-based biopolymers. A Design of Experiments approach is used to assess which
parameters have a significant effect on the overall accuracy of a print. A unique,
sterile rapid prototyping machine was designed and constructed to complete all
experiments. A predictive empirical model is created through a series of regression
experimental design analyses to determine the accuracy of a print compared to the input
CAD dimensions. The inner diameter of the extrusion tip, extrusion flow rate, and
printing pattern proved to have the greatest effect on the accuracy of the printed part
when printing with an aqueous 10% silk, 2% glycerol, and 88% water solution. Use of
another solution could require further testing for parameter optimization. With the
values of each significant parameter, the accuracy model can determine the necessary CAD
dimensions to acquire a final part with desired dimensions. Rapid production of accurate
and biocompatible parts can play an influential role in the biomedical industry by
optimizing scaffold production and building implantable tissues with reduced labor
Thesis (M.S.)--Tufts University, 2015.
Submitted to the Dept. of Mechanical Engineering.
Advisors: Thomas James, and David Kaplan.
Committee: Jeffrey Guasto.
Keywords: Mechanical engineering, and Biomedical engineering.read less