Baling essentials

As the heartbeat of a MRF, operators should pay close attention when selecting balers for these facilities.

Photo courtesy of Sierra International

staple in any material recovery facility (MRF), balers essentially dictate the revenue capacity of the entire operation. It’s a machine that all MRF operators know they need, but selecting the right baler—and running it properly—often can be overlooked.

During the 2021 MRF Operations Forum Webinar Series, which originally aired Oct. 18-19, a panel of suppliers and operators discussed just how much a baler affects MRF operations and what operators should prioritize to select the right machine and maximize its use.

“[Several years ago at the MRF Operations Forum] a panel of MRF operators was asked what piece of equipment in a MRF is the most important, and the answer was unanimously the baler,” said Nick Davis, product designer for San Diego-based CP Group. “Yet, when a MRF is being designed, budgeted and purchased, the baler is oftentimes an afterthought when it comes to making the budget.”

This notion is even more important considering how baling has become a more difficult task in recent years. With the increase in plastic scrap and old corrugated containers (OCC) in inbound material streams, along with the decrease in mixed paper, some MRF operators’ balers are struggling to keep up.

“Plastic has a low input density and requires frequent changeovers,” Davis said. “And OCC has lower input density than paper. Compacting to the same output density takes longer. So, as a result, there’s a lot of MRF’s struggling to keep up.”

Affordability versus operational needs

One theme was repeated among the panelists: With the need for higher spending on other aspects of a MRF, such as optical sorters, balers sometimes can be overlooked.

“You box yourself in when you’re looking at some of these operations when it comes to budget,” said Rob Taylor, area manager for plant operations at Phoenix-based Republic Services. “You look at how much you want to spend on a system, and then whatever is left on the backside is what you spend on the baler. I think we fail ourselves when we do this.”

He said the baler is the heartbeat of the facility, so it’s important to consider how it will need to be used rather than purchasing the lowest cost option. Considerations include what shifts the MRF will be running, the desired return on investment for the machine and the system’s overall speed.

Apart from the purchase price of the baler, it’s going to cost an operator a large sum to integrate the machine into the system. Taylor said operators need to consider the type of operation they are running before deciding which baler will work best. It could make sense to have a redundancy in the system (two balers), for example, if a MRF is running a two-shift operation and needs a baler to run six days a week.

“You may need those two balers to keep those operations running when you think about potential downtime events,” he said. “[Operators should consider] if it makes sense to spend a little extra money on the front side rather than trying to skimp on the front side, and then finding out that you don’t have the throughput capacity that you need and bottleneck yourself on the backside of your MRF.”

Weighing external factors

Beyond finding the right machine at the right price, integrating any piece of equipment into a MRF requires considering many other elements. Conveyors, the distance from materials and other pieces of equipment a MRF is using all can have an impact on the size and selection of a baler.

“Sometimes, you’re handicapped by the height of the conveyor,” said John Sacco, president of Bakersfield, California-based Sierra International Machinery. “And when a brand new MRF has been designed, you have to take in consideration the proper height to feed a baler for the input density. If it’s too low, you’re just going to choke the baler and its capability of producing what it can.”

In addition to height, the angle of the conveyors can pose serious problems if they aren’t measured correctly for the baler. “It can be the difference to where your baler isn’t the issue, it’s the design of what’s getting the material to [the baler] that’s an issue,” Sacco said.

The materials being processed also contribute to the type of baler a MRF operator will select. If multiple commodities are being baled with a single-ram baler, for example, it will require additional changes that will add time to the baling process. “You have to know whether you can afford the time [to make those] change,” Taylor said.

For some MRF operations, it could be completely doable. For others, a two-ram baler that is preprogrammed to handle multiple commodities could be the better choice.

Location also is critical. The time it takes to run materials from point A to point B will have an effect on a MRF's overall efficiency.

“Real estate is a valuable commodity in a MRF,” Sacco said. "Operators should know how much space they have to use and how to utilize it.”

Something that seems obvious but can vary greatly based on location is a facility’s ability to provide the baler the power it needs to function.

“One of the first things we look at when we’re sizing balers is available electricity,” Taylor said.

He said a MRF’s design also is a key factor in determining a baler’s output.

© Pavel /

Managing productivity

Once a baler is installed and running, effectively operating it in the context of the overall system will let operators get the most out of the machine.

Sacco said operators should consider the percentage of their baler’s operational capabilities they want to use. If the machine is designed to run 10 tons an hour, that might not mean the operator should always run it at full capacity.

“You have to be realistic [about the capacity],” Sacco said. He noted that it can be worthwhile to drop a baler’s capacity down to match the true capacity the MRF is processing, which factors in a facility’s downtime.

Recognizing the types of materials to be processed also is key to ensuring proper baling operations. Taylor said MRFs tend to be processing more OCC now than in the past.

“The fact that we’re trying to get that brown out of the mixed paper, get it over with the OCC, it’s taken up a little bit of our capacity,” he said. “If you got a single-ram baler that you’re running on your commodity, you’re losing some of that time to do your containers. So, the stream is highly important when you’re designing and trying to figure out exactly what kind of baler you’re going to put in.”

The goal is to avoid a bottleneck in the entire system, Taylor said.

Age also factors into baler operation, but Sacco said balers technically don’t lose speed unless components are wearing out. “If you’re doing your tune-ups and doing your maintenance, you’ll be able to identify when something isn’t right,” he added.

The mechanics

Spec sheets can be full of pages and pages of details. Focusing on some of the key mechanics of a baler can lead to successful integration and use.

Sacco advised paying attention to ram face pressure and ram force. “The higher the density there, you’re going to be able to make a heavier bale,” he said.

Also, when looking at additional mechanical details, such as pounds per square inch (psi), Sacco said higher pressure (4,500 psi, for example) is going to use a smaller cylinder compared with a baler that offers lower pressure.

Taylor and Sacco noted that when it comes to performance, horsepower and pressure can have a counterintuitive relationship. “A high-pressure baler actually needs to offer less horsepower. Horsepower doesn’t necessarily mean speed. It’s all in how that horsepower is applied getting that cylinder to move,” Sacco said.

And if a nearly 30-page spec sheet isn’t enough to digest, other considerations should be a focus, too. “Buying a baler is like having a doctor … you want to get a second opinion. Go out there and understand your options,” Taylor said.

He said comparing one feature on balers isn’t enough, because one machine may have a higher horsepower but the other may have more pressure. Taylor encouraged MRF operators to talk to other operators. “Find out what their utility bill looks like,” he said. “That says a lot when it comes to running these balers.”

The author is the conference producer for the Recycling Today Media Group and can be reached at

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