Electric Injection Molding Machines vs. Hydraulic Machines

When picturing injection molding machines in your head, you may have visions of enormous hydraulic machines lifting, stamping, injecting, and pressing molds through an assembly line. If so, there’s a good reason for it; hydraulic injection molding machines dominated the industry up until the 1980s. They were the only choice for injection molding for a very long time. Hydraulics were the perfect solution, having enough force to clamp two halves of a mold together while the plastic was injected, then cooled.

In the early 1980s, things changed. Electric injection molding machines came on the scene and, with time, have become hugely popular. For manufacturers, it is not so much a matter of electric injection molding machines vs. hydraulic ones as it is a matter of when to use each type of machine. Today, many manufacturers, including Baytech Plastics, run both types of machines, depending on the project’s needs.

The Benefits of Electric Injection Molding Machines vs. Hydraulic Machines

Electric machines cost more at the time of purchase than hydraulic machines but pay for themselves over time. Some of the reasons why the industry has moved to electric injection molding machines vs. hydraulic ones are:

  • Lower operating costs. Hydraulic machines are always drawing power to maintain hydraulic pressure, even when they are not in use. Electric machines operate under an on-demand system, only drawing power while in use.
  • Quicker start-ups and less wait time. Electric machines do not need time to warm up or cool down as hydraulics do. This is because electrics do not need oil to operate. The lack of oil and cool operating levels of electricity also eliminates the risks of fire and material contamination due to leakage.
  • Low maintenance. Since they don’t use oil, electric machines do not have the same consumable costs as hydraulic machines do. They don’t need filter replacement and there are no hoses, valves, or pumps to maintain and replace.
  • Digital controls yield greater precision. Computerized electric injection molding machines provide precise control over every step in the process. This yields a very high degree of accuracy and enormous improvements in repeatability compared to hydraulics. When comparing electric injection molding machines vs. hydraulic ones for high-precision parts, there is no comparison; electric wins.
  • Ideal for clean rooms. The lack of heat emitted by electrics makes them particularly well-suited to sensitive production processes such as those in clean rooms or on temperature-sensitive production runs.
  • Quicker runs. Without the need for oils and components that need to warm up, electric machines can get the job done faster. Electric machines operate on a series of independent motors which control each process. This means electrics can get up to speed faster and at independent stages which hydraulics cannot do.

There is Still a Place for Hydraulics

Just because electric injection molding presses are becoming more common, does not mean there is no longer a need for hydraulic systems. Hydraulics still provide enormous pressure to keep molds sealed during the injection molding process; 3 to 4 tons per square inch is the standard and some machines go even higher. These high-pressure levels are needed when making heavy parts, such as anything over 50 pounds.

Other benefits of hydraulic injection molding are:

  • Larger shot size to go alongside higher clamping forces
  • Highly resistant to wear and tear
  • Lower purchase price compared to electric machines
  • Exceptional ejection capabilities and injection rates

Benefit from Both Types of Processes at Baytech Plastics

Baytech Plastics uses both types of injection molding machines, allowing us to meet a wider range of customer needs. The diversity in our equipment means we can tailor the process to best meet the needs of each individual project.

To learn more about our capabilities or to discuss your upcoming project with us, contact Baytech Plastics at (705) 526-7801 or send us a message.