Energy Consumption Variability in Life Cycle Assessments of Injection Molding Processes: A Critical Review and Future Outlooks

Progress has been made in applying life cycle assessment (LCA) towards the injection molding of polymers. After reviewing the methodology utilized in existing literature, however, it was found that the use of life cycle inventory (LCI) data did not accurately account for the many factors within the injection molding process that effect overall energy consumption. More specifically, the LCI databases referenced contained averaged energy consumption measurements from different injection molding systems. The use of such measurements - derived from factors such as machine type, processing temperature, and cooling requirements - is inherently flawed as the many variations in the injection molding process cause different applications of the injection molding process to have highly varied energy requirements. As such, to accurately account for this variability, future life cycle analyses of the injection molding process will require the use of a system capable of integrating this variability into the environmental impact assessment of those processes. This is demonstrated by a focused analysis highlighting the inaccuracies in current LCA methodology with respect to energy consumption.