Energy Saving Strategies for Plastics Injection Molding Operators – Part I

Over the past few years, we’ve frequently highlighted the importance of energy efficiency and how lubrication can help you achieve your energy savings ambitions. But, we’ve covered it regularly for good reason – it’s a critical topic that has broader impact across business and society, particularly in today’s energy challenged world.

Certain industries in particular are highly focused on reducing their energy consumption, including the plastics industry. Plastics injection molding machines consume enormous amounts of energy, and improving their efficiency can have an impact on an operation’s overall energy consumption.

That’s why, last month, Adam McMurtrey, one of our U.S.-based field engineers, presented a technical seminar on energy savings strategies at ANTEC, the largest plastics technical conference in the U.S.

The session was well received by an audience of 40 or so engineers and we thought it would be valuable to share his insights with the Mobil SHC Club community.

If you’re in the plastics industry, or if you operate hydraulic equipment of any kind, this three-part tip series is for you. We hope you enjoy these tips, and please let us know if you have any questions via the comments section below!

ENERGY SAVING STRATEGIES FOR PLASTICS INJECTION MOLDING: LUBRICATION

Plastics injection molding machines require an extensive amount of energy, and energy costs typically represent one of the major line items in a company’s operating budget. A typical injection molding operation spends almost as much on energy expenditures as it does on direct labor. As operators look to reduce costs and enhance sustainability, they typically turn to the more obvious levers – such as new equipment, lighting retrofits, and more. But, one of the easiest and most frequently overlooked opportunities to improve energy efficiency is lubrication. This paper outlines how lubrication influences energy efficiency, key lubrication-related energy saving opportunities, and how operators can implement the right lubrication strategy to reduce energy costs, improve their bottom line, and enhance sustainability.

Injection molding machines: optimizing for energy efficiency

Today’s plastic injection molding machine technology is far more energy efficient than 20 years ago. At a conservative estimate, modern hydraulic plastic injection molding machines are 25% more energy efficient than those manufactured in 1997. Meanwhile, today’s best all-electric machines may be up to 80% more energy efficient than their 20-year old hydraulic predecessors.

But, in almost every case, the cost of energy required to run a plastic injection molding machine over a 10- year period will be greater than its initial purchase cost. This cost gap will only widen as energy prices increase.

For this reason, energy assessment must become part of the purchasing process for every new plastic injection molding machine. Considering the whole life cost of a machine is difficult but it is the only way to control future energy expenditure. It will help ensure that an attractive low cost machine does not become an energy hog that raises production costs through its entire lifetime. This includes looking at every aspect of the machine’s operation – down to the lubricant used.

Check your hydraulic oil

Hydraulic oil expenditure represents a fraction of the cost of running plastic injection molding machinery. But, a small change in hydraulic oil can result in big performance breakthroughs, such as prolonged component life, improvements in overall equipment efficiency and reduced cycle times.

Operating challenges

Throughout the injection molding process, hydraulic oil is exposed to compression, shear stresses and a wide range of temperatures. Exposure to these conditions can trigger molecular breakdown in the oil, reducing its ability to lubricate and protect machine components. A conventional or lower quality hydraulic oil offers less lubricity and protection, forcing equipment to work harder – ultimately exerting more energy.

High temperature operating conditions will also cause oxidation within the hydraulic oil, which subsequently creates an increase in viscosity and a build of destructive lacquer. Along with oxidation and corrosion, hydraulic oils can also become contaminated by water, dust, wear debris and other materials throughout the injection molding process. Contamination triggers pump failures and ultimately increases filtration costs.

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