Date of Award

6-18-2021

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Additive Manufacturing, Injection Molding, Rapid Tooling, Simulation

Supervisor

Jill J. Urbanic

Supervisor

Ofelia O. Jianu

Rights

info:eu-repo/semantics/openAccess

Abstract

Injection molding and additive manufacturing (3D-printing) are two manufacturing solutions that are suitable to produce plastic components. The material extrusion-based additive manufacturing (AM) process deposits beads side by side through an extrusion to build prototypes. This process is capable of manufacturing complex geometries, but it is very expensive and slow. As a result, it is not the best solution for manufacturing low to medium (10-5000) production volumes. Additionally, there are limited materials for AM as compared to injection molding. Injection molding process is very fast, reliable, and low-cost to produce thousands of a single product in a short time. However, the initial investment for building the mold is very high and it may take up to several weeks to manufacture a good quality mold. To cover the gap between these two processes, a low-cost tooling solution with a reduced build time has been developed that is suitable for low to medium production. Internal features are integrated within the tooling to investigate the possibility of building internal channels that can later be optimized to improve the cooling efficiency of the tool. The developed tooling solution was designed for a hands-free door handle. Design for manufacturing (DfM) strategies were applied to the initial CAD design to make it suitable for an injection molding process. Finite element analysis (FEA) and injection molding simulations were used to conduct virtual studies on this low-cost tooling solution. To create the internal features, soluble material (SR-30 developed by Stratasys) was used and Aremco 805 epoxy was cast to create the mold cavities. After curing the epoxy, the soluble patterns were dissolved to create the final mold. The developed tooling was able to manufacture the J-hook with a dimensional precision of approximately 1% - 3% of the desired geometries. Additionally, no sink mark or shrinkage was observed on the surfaces of the final product. Most importantly, the cost of the solution was kept under 500 CAD dollars and complex internal features were built without any additional support structure on the inside. Build time of the J-hook was reduced from 3 hours to less than 2 minutes and most importantly, the piece price of each J-hook was lowered by more than 44 CAD dollars per piece.

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