Packaging Corner: How to pick the right stretch wrapper
June 01, 2012 - MMH Editorial
When applying stretch wrap to a unit load, many facilities rely on manpower. But wrapping by hand has its downsides, increasing the risk of worker injury and inefficiently using stretch film, says Steve Fleming, director of sales at the Wulftec/M.J. Maillis Group.
“Based on film costs alone, a machine can be justified within two years for a facility currently hand wrapping as few as 10 loads a day,” Fleming adds. “Plus, there are ergonomic and sustainability benefits.”
In addition to removing the worker from the process, stretch wrapping machines use rollers that pre-stretch film by three to four times before applying it. The load is more consistently secured with up to 50% less film.
“Film is a petroleum product, and its cost has increased roughly 15% since January 1,” says Fleming. Using a return on investment calculator will help determine the potential savings from a switch.
Those cost savings, says Fleming, often prompt a machinery purchase. The two basic styles are turntable, which rotates the loads as a static applicator feeds the film, and rotary arm, that uses a carriage that revolves around the load to apply the film.
To pick the right stretch wrapper for your application, consider the following:
1. Load configuration. Unstable loads—mixed pallets or column-stacked (instead of interlocked) cases, for example—are not stable enough to be rotated on a turntable stretch wrapper. Facilities that wrap multiple types of stable and unstable loads would benefit from the versatility offered by a rotary arm model as well, even though they’re more expensive than turntables.
2. Load weight. Turntables have a top weight capacity from 3,000 to 5,000 pounds, says Fleming, so loads weighing that much or more will produce a lot of wear and tear on the turntable’s drive system. Alternately, loads under 500 pounds are often too light for a turntable wrapper without special modifications that hold the load securely from the top. In both cases, a rotary arm model might be better.
3. Process. Wrappers are either fully automatic (self-feeding loads) or semi-automatic (loads placed by pallet jack or lift truck). Also, says Fleming, do you wrap loads throughout the day, or all at once at the end of a shift? Your process will help you pick the right machine.
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