When it comes to handling bulky materials,
there’s probably no more versatile piece of equipment
than the baler. Today’s balers handle a wide variety
of scrap material, including metals, corrugated, wood, paper
and the focus of this month’s spotlight - plastics.
Choosing the right one depends entirely on what you’re
baling, and the optimum throughput for your operation.
The most commonly baled plastics can be divided into two
broad categories. First, there is PET, or PETE – known
among chemists as Polyethylene Terephthalate. This is the
familiar material that nearly all of the plastic containers
for soft drinks, mouthwashes, peanut butter and salad dressings
are made from.
Among the inherent characteristics of PET is “memory,”
or the tendency for the material to spring back to its original
form after pressure is applied. To resist the “spring
back,” balers used for plastics often feature “restraining
dogs” that keep compressed plastics from creeping
up the walls inside the baling chamber. As pressure forces
the material down, the dogs help keep the compressed load
Tom Stevens, president of Wolverine Recycling Services,
Inc. of Rochester, Michigan, distributor of baling and related
recycling equipment throughout the Great Lakes region observes,
“Many soft drink containers are returned with caps
still in place. Baling them often requires that they be
run through a perforator prior to loading in the baler.
The perforator punctures the containers and allows air to
escape as the ram compresses the load,” he said.
Due to the nature of the material, PET places special demands
on the hydraulic system of the baler as well. “Baling
PET containers can require ram face pressures of up to 225
psi,” said Stevens. Larger cylinders are needed to
produce the additional force to assure a desired thousand
The second broad category of frequently baled plastics is
HDPE, or High Density Polyethylene. Examples of this type
of plastic include milk, water and juice bottles, trash
and shopping bags; detergent, yogurt and margarine containers.
While there are plenty of similarities in the equipment,
baling HDPE is less demanding than PET. According to Wolverine
Recycling Services, Inc., “Balers used for high density
plastics applications will typically have ram face pressures
in the 70 psi range.”
In addition to special considerations for plastics, balers
are commonly divided into two distinct design types. Vertical
style balers feature rams that compress downward, pushing
the load under force into the baling chamber. Well suited
to smaller volumes, vertical balers require less space and
are simple to operate, but are limited in the size of bales
and the number of bales per hour that can be produced. Some
of the more popular applications for vertical balers include
retailers and other channel members who empty a variety
of corrugated containers.
Horizontal balers are designed for higher volume operations.
Mike Schwinn, sales manager for Maren Engineering said,
“Cycle times are generally much quicker with a horizontal
baler, because material is loaded into a feed hopper while
the ram continues to cycle. Vertical balers are typically
loaded by hand and can take as long as 50 seconds to cycle
through. Some of the faster horizontal models take as little
as seven and a half. Automatic wire tie systems boost production
as well. When operators aren’t spending time tying
bales, it speeds things up considerably,” he added.
Maintenance on a plastics baler varies, depending on the
primary material being baled. Generally, the more sophisticated
a baler is, the more maintenance it requires to keep it
in top running form. According to Mike Schwinn, “The
hydraulic components on a vertical baler should be inspected
annually. Horizontal balers need monthly inspections and
possible renewal work on the many more wear items, such
as floor, ram, hold down bars, shear beam and knife, and
the ram assembly,” he said.
Training is another important consideration for balers.
Jose Martinez, president of J.M. Hydraulics, Inc., manufacturers
of Baletech balers in Sun Valley, California said, “We
stress safety first. On each installation, we spend time
with customers to be sure everyone using the machine knows
how to properly load and operate the baler. Best practices
are reviewed and we cover the details so everyone is confident
using the equipment.”
Regardless of size or type, balers play a vital role in
recycling plastics. Reducing volumes and improving efficiencies
help to ensure that materials are recovered and recycled
by the most cost effective means possible.