The Promise of All-Electric Injection Molding Machines: A Promise Kept?

Panel: Panel 1. Industrial Energy Efficiency Measures and Technologies

Author:
Michael Socks, Vermont Energy Investment Corporation

Abstract

All-electric plastic injection molding machines were developed to use electromechanical actuators to eliminate fluid power (hydraulic pumps, control valves, and actuators) from the machine. This new technology holds the promise to reduce energy consumption, improve control, and increase productivity over the conventional hydraulic technology. These benefits have been widely touted by all-electric machine manufacturers based on generic mold testing and client testimonials.

This paper further investigates the potential of the all-electric technology and reports on the experience of one Vermont manufacturer. It includes a case study of side-by-side performance of an existing hydraulic and a new all-electric machine producing similar parts. Energy consumption of each machine was monitored over a one week period. Cycle time and shot size information was used to calculate the specific energy consumption of each machine. The hydraulic machine was found to require 0.278 kWh per pound of plastic processed compared to 0.073 kWh per pound for the all-electric machine. Using the purchase of a new hydraulic machine as a baseline, a financial analysis revealed a 31% internal rate of return for the customer based on energy savings alone.