3 Ways to Increase Energy Efficiency in Injection Molding

In injection molding (a versatile process used to produce a wide variety of end products), 90 percent of the energy costs go toward electricity. This makes electricity costs—and the ability to reduce those costs—of prime importance. There are three processes that represent good areas of focus for increasing energy efficiency in injection molding: melting the polymer, forcing it into the mold, and then cooling down the polymer. Electricity for the hydraulic system is the No. 1 energy hog—and an emerging trend in plastics is replacing hydraulic with all-electric molding machines. But there are plenty of opportunities for efficiency and reducing energy consumption besides buying expensive machinery. Here are three different areas to focus on for improving the energy efficiency of your plastic processing.

All-Electric Machines

The trend in energy efficiency in injection molding is moving away from hydraulic machines and replacing them with all-electric machines, which can reduce energy usage anywhere between 30 and 60 percent. Because their power is provided by direct electrical drive, the need for the cooling of hydraulic oils is eliminated. The other major benefit of going all-electric is that it has a lower power consumption at startup, followed by lower maximum demand requirements.

Barrel Insulation

Barrel insulation jackets can reduce energy consumption by 50 percent. By reflecting the heat radiated from the barrel they reduce operating costs, decrease startup times and help ensure more consistent operating temperatures.

Variable Speed Drives

Electric servo drives are more energy efficient than hydraulics for injection molding presses. But all-electric machines cost more—and some experts still prefer the way hydraulic machines operate. Outfitting a hydraulic pump with an electric servo motor is a cost-effective energy saver for new machines, but too costly a retrofit for older ones. A less expensive energy efficiency in injection molding alternative, which can provide energy usage very close to electric servo drives, is a variable-speed drive (VSD). VSDs improve process control, lower power loss and reduce wear and tear on the motor.

In general, implementing best practices with your injection equipment can have a significant reduction in your plant’s energy consumption. Here are some tips to reduce your injection molding consumption.

  • Calculate life cycle costs for new machines (i.e., cost to purchase + cost to operate, including energy costs), which can reduce product costs by 3 percent.
  • Optimize parameters and cycle times, making sure you are not using more force or time than you actually need.
  • Make sure the machine matches the product. Appropriately sized machines, equipped with the specific screw, do the most efficient job.
  • Reduce scrap levels, which cause unnecessary energy consumption.
  • Be vigilant about maintenance, especially on heat exchangers and cooling channels.
  • Plan and control the startup and shutdown sequence to reduce “idling” time.

As you can see by these tips, at the heart of an energy-efficient injection process is smart management, best practices and the commitment to invest in a sustainable future. Even implementing just a few of these ideas can make a big difference to increase the energy efficiency in injection molding processes.

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