What is the number one challenge in a manu-facturing environ-ment? Labor concerns? Machinery breakdown? Safety hazards?

While all of these are genuine reasons for concern, they do not address the fundamental challenge for manufacturing facilities, especially those roll forming parts.

The number one challenge, by virtue of its direct relationship to the company's profits is production efficiency. Moreover, as competition increases and profit margin decreases, fabricators have an ever-greater need to find innovative ways to increase productivity without sacrificing the bottom line. A pallet decoiler can be a possible solution to the problem.

Roll formers have different demands from pallet decoilers than stamping presses do. Typically, roll formers run faster and require more frequent coil changeovers, hindering the roll former's uptime and increasing the chance of injury to operators.

Employing a pallet decoiler can allow a company to load an entire skid of material as it comes from the supplier. This cuts the amount of time needed to change a coil and, in doing so, increases the uptime of the roll forming machine.

Additionally, many companies have found that they can order lager coil outside diameters (ODs), some as large as 72 inches, since some pallet decoilers allow for running these massive packages.

The combination of larger coil ODs and loading multiple coils on a pallet decoiler increases the uptime of the roll former and in turn helps increase the productivity and profits of the manufacturing facility. The chance of the coil falling off of a "C" hook or cradle during the loading procedure is eliminated.

Power transmission components must be adequate for these higher speeds. Are the motor, gearbox, linkage, shaft, and bearings rated for the considerable speeds? Is the tension control mechanism sufficient to maintain safe control of the material when running at these high speeds? What about safety in an emergency stop situation? Is there adequate horsepower and/or braking capability to stop the load of 6,000 pounds (or what ever the skid weight may be)? How will the coil stay on the decoiler platform in these situations?

A few companies that have built units to run at these higher speeds have developed heavy-duty holding devices that mount to a platform. The operator loads the centering device, which is than adjusted to the coil's inside diameter (ID). This system requires that the pallet's crossboards not be within the coil ID, and most service centers will comply with a customer's request for this type of pallet design.

Especially at higher speeds, safety becomes much more of an issue. Therefore, it may be wise to thoroughly discuss these conditions with the pallet decoiler manufacturer before ordering.

Acceleration Time Another consideration is the acceleration time of the roll former. Many servo- or clutch-driven mills have instant acceleration. Acceleration time has direct impact on the amount of horsepower required to run an application. Once factors such as capacity, speed, and coil size have been calculated into the inertia equation, acceleration time becomes the most important variable. The horsepower required is inversely proportional to the acceleration (and deceleration) time. For example, consider an application calling for a I-horsepower motor at 2-second acceleration/deceleration time.

If the acceleration time were cut to 1 second, the horsepower would double to 2 horsepower, a significant difference. Conversely, if the acceleration/deceleration time were doubled to 4 seconds, the horsepower requirement would be cut in half, another significant difference.

However, fabricators are finding that using pallet decoilers on lines that run many materials can also be effective. One reason for this is the versatility certain models provide. Pallet decoiler manufacturers have designed models that can run a range of widths and gauges on one unit.

Also, the inherent safety benefit realized by using a pallet decoiler is a tempting cost justification. When an operator loads the pallet with a forklift, rather than individually handling the coils, safety is enhanced.

What about using pallet decoilers plant-wide? Consider the example of Pullman Industries in South Heaven, Michigan. With a new plant being built, the engineering staff was struggling with recurring bottlenecks in production. How could they roll formers producing at top level when coil changeovers were so frequent?

The company had used pallet decoilers in its other locations with good success.

After weighing the pros and cons of various coil handling methods, the company decided to employ pallet decoilers throughout the plant. Each of its 14 roll forming lines being installed incorporated a pallet decoiler to pay off the steel.

As mentioned previously, some companies also use pallet decoilers to allow for the use of larger OD coils. The company increased its coil ODs to 60 inches (form the previous 48 inches) and changed the controls on the roll former.

By employing these various changes, the company increased production 400 percent. The shops do not have any overhead cranes, reels, or cradles. One operator can now run two roll formers simultaneously.

Additionally, certain excessively high-speed applications (400 FPM or more), such as tube mills, can require tremendous amounts of horsepower. This factor will sometimes make a pallet decoiler cost-prohibitive.

Reducing coil changeover, increasing operator safety, and reducing mill downtime are all possible by applying a pallet decoiler to the appropriate roll forming application. Discussing the application thoroughly with the pallet decoiler manufacturer will help ensure a smooth transition to this alternative coil handling method.

By reviewing the limitations of pallet decoilers, roll forming companies can be realistic in their expectations from the machinery.

When applied properly, pallet decoilers can help increase production efficiency and profits.

REPRINTED WITH PERMISSION FROM THE SEPTEMBER 1997 ISSUE OF THE FABRICATOR (R)
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