Scrap Articles

10 Nov.,2022


baler machine recycling

July/August 1991

Scrap processors and equipment manufacturers share their thoughts on what to look for and what to avoid in baling equipment.

By Jeff Borsecnik

Jeff Borsecnik is assistant editor of Scrap Processing and Recycling.

Understand your materials and your markets in detail before making equipment-purchase decisions, paper and plastic processors and processing equipment companies warn would-be recyclers of these materials.

You must know exactly what types and volumes of materials you will be processing to get appropriate advice on the purchase of baling equipment, says Robert C. Turner, president of C and M Co. (Winston-Salem, N.C.), which produces balers suitable for processing nonmetallics. Only the largest, most expensive balers can handle a wide variety of materials well, he says, adding that he has seen "hundreds of competitors' balers destroyed" by processing materials they weren't designed to handle.

It's also important to consider details about your scrap consumers before making an equipment investment, says Victor Storelli, region recycling manager for Recycle America (Miami), a Waste Management Inc. company, which processes paper and plastics, as well as glass and ferrous and nonferrous metals. Keep in mind not only consumers' scrap specifications, he advises, but also what transportation methods and costs are involved in moving materials to the market.

Looking for Density

Many scrap processors name density--as determined by the volume of materials to be baled and shipping requirements--as the key consideration in choosing a baler for paper and/or plastics.

In the paper arena, density is most critical for exporters, since often only very dense bales make export shipping worthwhile. Thus, says Jonathan Gold, vice president and general manager of Newark Group's North Shore Recycled Fibers (Salem, Mass.), and chairman of the Institute of Scrap Recycling Industries's (ISRI) (Washington, D.C.) nonmetallics division, if you plan to sell your paper overseas or to a broker with many export markets, "look for high-density balers-maximum weights in export containers with a minimum-size bale."

For domestic sales, paper processors and baler manufacturers seem to agree that most balers can deliver adequate density. What needs to be examined, the experts emphasize, is a machine's ability to move volume. In addition, says Scott MacDonald, director of sales and marketing for Global Equipment Inc., a Spokane, Wash. based baler manufacturer, feeding is the key to bating paper well. He says packing some grades in some kinds of balers requires preconditioning-stirring up or "fluffing" the scrap-before baling to create high-quality bales.

Plastics can be more challenging. The scrap's "memory"--its stubborn refusal to remain compressed when flattened--makes baling plastics slower and more difficult than other materials. Evan Koplin, vice president of marketing and finance for Macon Iron & Paper Stock Co. Inc. (Macon, Ga.), which bales a wide variety of metals, paper, and plastics, puts it this way: "If you bale a load of low-copper clips, the bale stays put. But if you bale plastic milk jugs, some of them will leap right out of the bale." The memory force can be so strong, in fact, Koplin says he's heard plastic bales burst apart, sounding "like an explosion."

Polyethylene terephthalate (PET) soft drink bottles are even tougher to flatten than high-density polyethylene (HDPE) milk jugs and they bounce back more, reports MacDonald. He says part of the answer to this problem is perforating the plastics before they are baled-if you can invest in this additional piece of equipment. Another possible solution to keeping plastic bales from bursting, MacDonald suggests, is to increase the number of ties placed on bales and/or the quality of the wire used. If you decide to try a higher quality wire, he adds, make sure you are getting the wire you ordered. C and M's Turner, however, recommends getting the right baler to do the job in the first place, noting that it is possible to put more wire on a bale to contain it than the bale is worth.

Using an appropriate baler can have even greater implications. Turner says he has seen accidents caused by doors on other firms' balers blowing open when compressing plastics they weren't built to handle.

One explanation for this, notes Michael Okerstrom, marketing manager for Harris Group (Minneapolis), a manufacturer of balers and other processing equipment, is that it takes "significant" pressure to flatten PET bottles with lids intact, pressure only a large baler may be able to supply.

Density of plastic bales has not yet become a critical market consideration Koplin says, but it soon will be. The key items to look for in a baler to produce maximum density, according to Global's MacDonald, are the extent to which the ram penetrates into the chamber and the pressure it delivers. He says that a ram that travels completely through the chamber win produce tighter bales than one that doesn't because the latter ends up compacting some material only secondarily, by pressing it with more material that is being crushed rather than being compacted by the ram itself.

Bale size, on the other hand, can play a role in getting top dollar from consumers and may also be a consideration for facilities with tight storage constraints, because the bigger the bale produced by the machine, the more storage space required for material waiting to be baled. The Council for Solid Waste Solutions (Washington, D.C.) estimates that storing the uncrushed scrap plastic needed to make a single 750-pound bale of PET would require 16 to 25 cubic yards of storage space. For an HDPE bale of the same weight, the group says 25 to 30 cubic yards would be needed.

Bulky paper grades also require large amounts of storage space. This issue is most pressing for facilities handling a variety of bulky materials with a single machine.

Volume and Engineering Evaluations

Plastic's tendency to reexpand after being compressed not only complicates density considerations, but also slows the bating process. Bating plastics is mostly baling air, says Turner, noting that it takes three or four times as many strokes to make a bale of plastic bottles than it does to bale aluminum cans because of the low density and memory of the plastic. For those used to handling paper, Gold offers this comparison: If you bale 15 to 20 tons of corrugated in about 40 minutes, you would only be able to process 4 to 5 tons of PET bottles with the same machine in the same time period. Precrushing or perforation and the baler's effectiveness at limiting springback can help speed the process.

Factors determining the volume a baler will be able to process include the size of its chamber, its cycle time, and the speed at which materials are loaded, say the experts. With low-density materials such as plastics, the loading time necessary to produce a bale is increased, making manual loading economically unfeasible for many.

Another consideration in finding a baler to meet your volume requirements is machine durability. "Look for equipment that will stand the pounding our industry gives it," says Gold, noting that his company is prepared to pay more for a high-productivity machine with few maintenance problems. "Downtime is a loss of money," he says. Gold also suggests choosing a baler that is designed to prevent and relieve jams, for the same reason.

Storelli recommends that shoppers look at the weight of the machine and says "the more steel the better." He suggests buyers also look for solid steel beams and quality welds. Horsepower and piston size are important considerations as well, he adds, noting that a larger piston delivers greater force for compaction but cycles slower, resulting in fewer tons packed per hour.

Storelli says shoppers should also take into account the size of pumps and reserve tanks for a baler's hydraulic system. Arnie Powell, an engineer for Global Equipment, stresses the importance of smoothly operating hydraulics supported by a heavy structure built to handle the pressure hydraulic systems deliver. He adds that buyers should look at the workmanship in the machine's assembly and whether all parts are naturally integrated into an intelligent overall design.

Turner cautions that "anyone can make a piece of steel look good. The real test is the test of time." He suggests carefully researching the reputation of a manufacturer's balers and recommends that a safe operating history be a key factor in the evaluation.

Can One Machine Do the Job?

Many of today's balers offer the volume capabilities necessary to handle a variety of materials, but is it wise to rely on a single baler for your paper, plastic, and even nonferrous needs?

Users' and manufacturers' reactions to that question are mixed. Going to one machine decreases the number of workers required to operate machines and also often limits the equipment and labor necessary to preprocess materials, because the larger balers are able to handle more materials without pre processing, some note. But others fear depending too heavily on one large machine.

Storelli and Global's Powell say that some of today's high-end machines may be able to handle nearly everything processed by a given facility, but note that certain materials, such as foam rubber, still need to be processed by a specialized machine. In addition, Turner cautions, balers that can handle many materials effectively often are designed for a volume beyond that handled by most scrap processors.

Another potential problem related to using a single baler to process a variety of materials is Contamination, which has particular significance in processing plastics because plastics are usually purchased only in strictly segregated, clean lots, with little market for mixed resins or "slightly" contaminated loads.

When using one baler to process different materials--or even different grades of a particular scrap item--it's important to note that some material typically remains in a baler's chamber or on the loading belt, says Storelli, noting that "it might take a minute or it might take an hour" to thoroughly clean out the baler. He also points out that for plastics, unlike for most materials, paper is a "serious contaminant” that can cause major problems for consuming operations.

Koplin adds that you "almost have to get a baler spotless" when switching to bale plastic after any other material, including another plastic. His firm is beginning to concentrate its baling on two machines: one for plastics and another for a variety of other scrap commodities. Previously, it operated a handful of machines, each largely dedicated to a single material. He notes that Macon Iron & Paper Stock is currently producing plastic bales that meet proposed ISRI plastic specs with a baler the company found in a load of scrap and reconditioned.

Contamination concerns also can be addressed by planning the order in which scrap is baled. For instance, Storelli says, it is best to bale high grades of paper first on any given day, followed by medium, then low grades because the lower the grade, the less sensitivity to contamination by other grades.

Peripheral Considerations

While a baler is the primary piece of equipment needed to process paper and plastics, supplementary products may need to be incorporated into your purchasing decisions. For instance, paper and plastics, with their relatively high unprocessed volumes, often require conveying systems for quick and efficient loading. Gold suggests using conveying systems that allow hand sorting of paper or plastics to improve the quality and appearance of bales. His firm also uses a "hogger/chopper" system with its balers to produce "more attractive" bales for the domestic market. Storelli notes that the width of a conveyor is a key consideration for handling some paper grades, especially corrugated, which demands wide belts to avoid precutting.

Perforators and precrushers can ease baling of plastics substantially, say processors and equipment manufacturers. "AR plastics should be perforated before being baled--that's preferable," says Storelli. Perforation reduces the memory of the plastics and removes liquid from plastic containers, improving the quality of bales, he notes. Turner points out that perforation also can reduce the storage space required for plastics awaiting baling by 40 to 50 percent and helps decrease the number of strokes required to produce a bale, speeding processing.

Be aware, warns Storelli, that some peripherals can limit a baler's usefulness. A shredder attached to the machine, for instance, might prevent its use for plastics, he says, unless the shredder can be circumvented.

Processing space should also be considered. Storelli estimates that a processor planning to handle bulky paper grades at a worthwhile volume requires 40,000 to 50,000 square feet of building space for operations and storage; a 27-foot ceiling to accommodate a conveyor and feeding chute and stacks of bales as well as allowing for containers to be tipped for unloading; and a total of 3 to 4 acres of land. For higher, less bulky grades, he suggests a building with at least 30,000 square feet of floor space and a 22-foot ceiling.

Plastics are similarly demanding of space if handled in volume. In addition, says Storelli, plastic processors should plan to build a holding bin to keep these lightweight materials from blowing away, and also should consider having a tractor to load the conveyor, a forklift to remove bales, and a building at dock height.

Above all, the experts counsel shoppers, once you've carefully evaluated your baler needs, go see the equipment in action on the materials you plan to handle.


Baler Basics

Balers haven’t changed much in basic design over the years, according to several manufacturers and users, though power and features have been improved. There are basically three types of balers.

Vertical balers, commonly used by grocery stores to compact corrugated boxes and other materials, are the least expensive, least powerful, and slowest kind. They are also typically easiest to operate and require very little space. Prices vary widely, but several authorities estimate their cost at $8,000 to $25,000. Vertical balers are usually loaded by hand, but some have been adapted to allow mechanical conveyance. Bales from this type of machine are tied by hand.

For getting into plastics, according to “How to Implement a Plastics Recycling Program,” published in 1991 by the Council on Solid Waste Solutions, a properly chosen vertical baler (equipped with a conveyor-load system and a crusher or perforator) is preferred over larger machines for production rates of up to 3,000 pounds per shift, given such a machine’s ease of operation, low cost, and savings in space and power use.

Koplin and several other processors say such a system may be satisfactory, as long as the machine is able to handle the wear and tear, but Okerstrom suggests that while such a setup might suffice for certain uses--such as compacting materials to save space--it might not be able to produce bales dense enough for economical shipping or to satisfy consumers.

Single-ram horizontal balers, probably the most common nonmetallic and nonferrous balers used by scrap processors, are generally agreed to be more powerful and much faster than vertical machines. They require significantly more space, power, and expertise to run, however. Horizontal balers typically have a larger hopper for feeding and are usually loaded by a conveyor or other automatic system. They are usually equipped with semiautomatic or automatic tying systems and often produce a continuous stream of bales. Horizontal balers range widely in price, but are generally many times more expensive than vertical balers. Some horizontal balers are designed for very high volumes of material and can produce quite dense bales.

Storelli estimates that processors must handle 2,000 to 3,000 tons of scrap paper per month to make operating a high-density horizontal baler economically feasible, but he suggests the processors purchasing such a machine for paper may be able to supplement the volume of paper handled with plastics and aluminum cans, possibly moving these materials to other smaller or specialized equipment once an appropriate paper-handling volume is reached.

The third type is a variation of the horizontal baler, a two-ram horizontal baler, which employs a second ram perpendicular to the baling ram to eject finished bales from the chamber. These powerful and sophisticated machines have a very large chamber, able to accept such materials as large boxes without preparatory cutting. They bale against a steel wall instead of the previous bale, raising the density reached. These machines reportedly handle a wide variety of materials very effectively, but may cost several hundred thousand dollars.

C and M Co.’s Turner says that most two-ram balers are built to handle much more stress than single-ram machines.  •