Baler Supplement -- Interrupting the Work Flow

They are certainly never planned, and they are always unwelcome. Most baler owners, though, have experienced baler jams—operational malfunctions that bring with them temporary productivity barriers and the potential for serious injury.

From baler service managers to recycling operations personnel, no one claims to have come up with a way to completely eliminate the problem of baler jams. But there are ways to improve the odds and reduce one’s chances of repeatedly falling victim to the headaches caused by baler jams.

AVOID MISMATCHES

Different model balers are designed primarily to handle certain materials. Even though many balers are designed to compress several different commodities, even these multi-material models have their limits.

“You have to use the baler for what it’s designed for,” says David McGee, service manager with Marathon Equipment Co., Vernon Ala. “If you throw magazines into a baler designed to handle cardboard, or ferrous metals into a nonferrous baler, those materials may be too difficult to shear,” he adds.

This situation can bring on one type of baler jam commonly known as a shear blade jam. In these cases, the attempt to bale material for which the shear blade is not suited will prevent the blades from cutting all the way through, thus stopping the baler from completing a cycle.

“Most jams occur at the breaker bar or shear blade as the material is being cut,” says McGee. “These are the worst jams, in my opinion, because you have the wearing effect between the two shear blades. Your structure will start experiencing some wear prematurely if you don’t make some adjustments.”

Among the adjustments that can be made are examining the type of shear blade being used, determining whether too much material is being fed into the baler charge box, and ensuring there are properly tight tolerance levels on the shear blades.

In many cases, the “design of the shear blade is critical,” says McGee, who notes that serrated, angled and straight-cut blades all have proper uses for varying material types.

While many recent model balers have control panels with push-button settings specifically marked for given types of material, that advantage can be negated by simple oversight. “The wrong settings can certainly cause jams,” says one baler company engineer. “Plastic is different from corrugated which is different from newsprint, and those settings are programmed to handle very different tasks.”

WATCH THE WEAR PARTS AND THE CONVEYOR

Having the right shear blade in place will not prove helpful if that blade has been worn down beyond its effective life span. “Improper maintenance of shear blades can cause jams,” says one baler company engineer. “Not changing the blades often enough or not keeping the clearances proper are common causes of jams.”

Craig Adams, an engineer with C & M Baling Systems, Winston-Salem, N.C., recommends that baler owners keep a spare shear bar on hand. He also notes that most balers are now equipped with blades that can be re-sharpened for further use.

When it comes to overall wear and tear on blades and other baler parts, multi-material recycling locations can be among the harshest environments. “If somebody is primarily baling cardboard, but they’re putting in a lot of dirt and sand, you can cause a lot more wear compared to what it experienced at a trim line at a paper mill,” says Adams. “At places with commingled streams with glass and small bits of metal, that’s tough on the machine.”

While dull blades are a common cause of shear blade jams, another type of jam is most often caused by having too much material in the charge box or introducing unwelcome material into the charge.

Such jams can occur in two-ram balers when too much dense material (or a large foreign object) prevents the main ram from reaching the point of penetration that activates the ejection ram. The variables that can cause such baler stoppages are many.

One culprit is a conveying system that is feeding too much material too fast into the charge box, or is feeding material inconsistently. “It could be paper not going into the baler smoothly,” says Joel Litman, co-owner of Texas Recycling Surplus, Dallas. “Theoretically, you may have clumps of dense paper or gaps where there is no paper at all.

McGee says of such jams, “too much material is usually the culprit,” though he also singles out “material with an extreme amount of memory, such as plastic containers.”

While recyclers use both mechanical and manual means to ensure that foreign objects don’t get into a baler charge box, it does indeed happen. “You might get a butt roll or even an 18-inch metal printer’s roller that might slip through,” notes Litman.

At MRFs, it can be fairly common for an array of unwelcome items to accidentally enter the charge box. “At recycling locations, wood or steel items—even things like shoes—can get introduced. Keeping a clean infeed stream is important,” says Adams.

One baler engineer says the worst case jam scenario would involve “some inadvertently introduced metal that gets in there and you have to torch it out.”

Recyclers may also knowingly include material in their bales that just doesn’t lend itself to being baled. Adams cites phone books and magazines as objects in that category. “Any major non-compactable material you don’t want in there,” offers McGee.

Much of the burden of baler jam prevention lies with the personnel in charge of sorting and even procuring infeed material. “It’s important to train people to put the paper in uniformly,” says Litman. “One thing that has been helpful here is having the conveyor at the proper pitch. A conveyor going up that is too steep can cause paper to slide back down and give you an uneven infeed stream.”

Philadelphia Tramrail makes vertical balers, which are not subject to jamming according to general manager Mike Savage. But the company does offer a training video with its baler models that does address material ejection problems. “We offer a safety/operations video tape that demonstrates the ejection side of the process,” says Savage. “All of our balers also come with plates attached that show operational procedures, and obviously you want to follow those. If you skip some of those, you may well run into problems when it comes time for the ejection.”

Despite mechanical sorting advances, manual sorting is still helpful, Litman says. “If something looks out of the ordinary, we tell our employees to stop the conveying line if they have to and get the object out of there.”

TECHNICAL HELP

Baler manufacturers have introduced innovations that can help operators avoid jams.

Some models tie the infeed conveyor into the baler’s electronic control box so that if the charge box reaches the limit of material it can accept, the conveyor automatically stops. “We call it an infeed management system, and it limits the material going under the shear blade,” says McGee. “Our computerized balers also limit the amount of material that can go into the charge box after you reach a certain bale size,” McGee adds. “You can add more material, but it doesn’t really go into the bale chamber.”

Another helpful feature McGee touts are “full-penetration cylinders, which go virtually all the way to the wall, so you have, say, uniformly crushed cans instead of bales where the cans are flat on one end but almost in tact at the other end.”

Failing new technology, there are more time-tested ways to clear some jams. With most single-ram balers, a jam can be cleared simply by activating the manual mode and reversing the ram, which can push the material into a waiting bin.

Also, baler operators who believe their jam can be cleared with just a little more “oomph” can increase the PSI (pounds per square inch) setting on their baler and ram it through with a little more power. “But if it’s a major jam,” cautions McGee, “you may have to manually eject that particular bale without tying it off. Just get it out of there and start over.”

Paper recycler Litman says he does turn to the baler companies for advice. “I think it’s important to communicate with the baler manufacturer and your repair service. Sometimes they have suggestions that can help you minimize jams in the future.”

While advancements in technology and improvements in procedures offer baler operators reasons to hope that baler jams can become increasingly rare, neither processors nor engineers believe they are headed for extinction.

“They don’t happen too frequently here,” says Litman, “but it’s inevitable that they’re going to happen—it’s a piece of machinery. You just want to make sure you have people in your plant who know how to unjam it and that you have a good relationship with a baler repair service in your city.”

The author is editor of Recycling Today.