All Electric Injection Molding Machines: How Much Energy Can You Save?

Abstract

There are three basic types of injection molding machines (IMMs) currently on the market: hydraulic, all-electric, and hybrid. They each have a different way of driving machine processes. Hydraulic IMMs use hydraulic pumps, all-electric machines use only high-speed servo motors, and hybrid IMMs use a combination of hydraulic pumps and servo motors. It is widely accepted that all-electric IMMs are the most energy efficient of the three technologies. Surprisingly, available quantitative analysis of energy savings from all-electric IMMs is limited and much of it relies on manufacturer claims and limited real life performance data. Manufacturers and utility estimates of energy savings due to the installation of an all-electric injection molding machine are typically based solely on the type of IMM technology or the IMM technology type and throughput, also called the mass flow rate of production. This paper suggests that there are other factors that influence energy usage in addition to the mass flow rate, such as product type, product cycle time, injection temperature, clamping pressure requirement, screw length and clamping distance. This paper details the injection molding process and investigates specific factors that affect IMM energy usage and energy savings. Some all-electric injection molding manufacturers claim that the market for injection molding machinery will completely take over the plastic molding industry in North America. Do these quiet, clean, precise, repeatable, and energy-efficient, all-electrics be the new norm in North American plastic molding industry? Will hydraulic molding machines become extinct? If all-electric IMMs are not fifth generation, will they be able to deliver higher clamping force believed to be equivalent to the hydraulic machines? To what extent are hydraulic machines replaceable with all electric machines based on different applications? In this paper, we attempt to answer all the above questions. We will discuss the current market share of the different injection molding technologies. We will investigate the percentage utilization of the rated capacity of all three types of injection molding technology. We will address how the percentage utilization of all electric machines is comparable with the same capacity of hybrid and hydraulic machines. We will also assess the market potential of all three injection-molding technologies depending on their application, cost, capabilities and energy consumption. We will discuss the current market shares among hydraulic, hybrid and all-electric machines. Finally, we will also discuss the attitudinal and economic market barriers of acceptance of all-electric technologies.