Energy and Eco-Impact Evaluation of Fused Deposition Modeling and Injection Molding of Polylactic Acid

Sean O’Brien,John Rapinac,Emmanuel Ugo Enemuoh,Venkata Gireesh Menta,Abdulaziz Abutunis,Labiba Imtiaz Kaya

doi:10.3390/su13041875

Sean O’Brien, John Rapinac + Show 4 more

Open Access

https://doi.org/10.3390/su13041875

Copy DOI

Journal: Sustainability	Publication Date: Feb 9, 2021
Citations: 13	License type: CC BY 4.0

Affiliation: University of Minnesota, Duluth

Abstract

There is limited knowledge about energy and carbon emission performance comparison between additive fused deposition modeling (FDM) and consolidation plastic injection molding (PIM) forming techniques, despite their recent high industrial applications such as tools and fixtures. In this study, developed empirical models focus on the production phase of the polylactic acid (PLA) thermoplastic polyester life cycle while using FDM and PIM processes to produce American Society for Testing and Materials (ASTM) D638 Type IV dog bone samples to compare their energy consumption and eco-impact. It was established that energy consumption by the FDM layer creation phase dominated the filament extrusion and PLA pellet production phases, with, overwhelmingly, 99% of the total energy consumption in the three production phases combined. During FDM PLA production, about 95.5% of energy consumption was seen during actual FDM part building. This means that the FDM process parameters such as infill percentage, layer thickness, and printing speed can be optimized to significantly improve the energy consumption of the FDM process. Furthermore, plastic injection molding consumed about 38.2% less energy and produced less carbon emissions per one kilogram of PLA formed parts compared to the FDM process. The developed functional unit measurement models can be employed in setting sustainable manufacturing goals for PLA production.

Highlights

According to the United States Energy Information Administration (EIA), the manufacturing sector is a significant source of energy consumption, and driving accessories in the manufacturing sector alone consume around 1.35 × 1019 J each year, generating about a 521 MT CO2 equivalent amount of carbon emissions [1]
We used a simplified life cycle approach and empirical models to compare energy demand and carbon emissions associated with forming polylactic acid (PLA) using Ultimaker
The PLA plastic injection molding, in general, consumed about 38.2% less energy and produced less carbon emissions per one kilogram of PLA formed into the final product compared to the fused deposition modeling process

Summary

Introduction

According to the United States Energy Information Administration (EIA), the manufacturing sector is a significant source of energy consumption, and driving accessories in the manufacturing sector alone consume around 1.35 × 1019 J each year, generating about a 521 MT CO2 equivalent amount of carbon emissions [1]. Since 2010, the United States has been recording the largest increase in energy consumption every year in both absolute and percentage terms. Optimizing current processes, adopting new techniques, and developing new technologies are paramount to limiting the increase in energy consumption and reducing carbon emissions [2]. AM technologies are typically considered to be environmentally sustainable due to the significant reduction in tooling, material wastage, and chemicals. Inventory reduction due to AM’s ability to form parts on demand further supports the sustainable manufacturing goals

Objectives

Methods

Findings

Discussion

Conclusion