Concept and Use of Pallet Decoilers in Rollforming

     This article discusses the concept and use of pallet decoiling, its benefits and limitations and what to consider if you are planning to purchase one. If you are like most rollformers, in the past 10 to 15 years, you have looked for ways to reduce downtime and improve your productivity. Most rollformers have overcome the obvious reasons for downtime, but as they delve further into their manufacturing processes, they are finding many surprises.

     One surprise is the amount of time it takes to change coils consistently. Briefly viewing your rollforming process, it may seem as though you are doing everything to reduce downtime. However, when you view how often production machinery is stopped to load or wait for material, you may see that a significant amount of time is lost. In the rollforming process, continuously running lines would be ideal. Today, the manufacturers of modern rollforming machinery are producing lines that run much faster. With this increase in line speed, a greater demand exists for coil handling equipment that can keep up. One of the ways to increase the productivity of coil handling is to increase the coil's outside diameter (OD). Obviously, with increased footage per coil, the rollforming line could run longer between coil changeovers. Here is where a horizontal pallet decoiler could be beneficial.

     With the concept of horizontal/pallet decoiling, the coil's diameter can be purchased up to the largest diameter offered by your supplier. It is not uncommon to see 72-inch diameter and even 84-inch diameter coils running on a pallet decoiler. The majority of coils are 60 inches in diameter. Because the coils on a pallet decoiler do not have to be upended, individual coils are not handled. The entire pallet of material can be placed on the pallet decoiler just as you receive it from your supplier. Usually, you break the pallet open and lift individual coils onto the arbor of the vertical reel or put the coil into a coil cradle. This may not appear to be a time-consuming project, but the operator has to wait for the forklift, crane or other device to load the coil on the arbor. On average, it takes approximately 15 minutes. If you purchase coils smaller than the master diameter, such as a 32-inch diameter coil, the operator has to stop the slitting line, cut the strips, tape the end, take the coils off the slitter mandrel and put them on the pallet. Then, the operator has to restart the line to finish the coil. A lot of time and scrap are involved in this process. If the supplier could produce your coils to the size of the master, it would not be necessary to stop in the middle of a coil. The operator could slit the entire coil once it is going.

Benefits of Pallet Decoiling

The following are pallet decoiling features:

1. Reduced material handling. Coils can be moved from inventory to production in one move. With pallet decoiling, the forklift truck brings the pallet out and places it onto the decoiler platform. Depending on the coil line speed, this could be a sufficient load of coils capable of lasting for a day or longer. Thus, floor space is saved.
   
   
2. Reduced coil damage. Often, many thousands of pounds of material are lost because of damage in loading or unloading individual coils. This is primarily damage to the edges of the coils, which cannot be straightened or a coil of material clocksprings, which is dangerous and costly.
   
   
3. Increased safety. Since employees are not handling individual coils, they have less chance of cuts, bruises, banged fingers, back injuries and more.
   
   
4. Improved employee productivity. Since employees will not spend as much time with setup, they will have more time to complete other tasks.

Limitations of Pallet Decoiling As with all processes, pallet decoiling has its limitations, which include:

1. Limited material thickness. The material has to go from vertical to horizontal in the transition process. If the material is thicker than .065 inch, the material becomes difficult to use.
   
   
2. Limited material width. The best widths to use are generally under 12 inches because material over 12 inches wide does not want to make the transition from vertical to horizontal.
   
   
3. Limited acceleration and line speed.

     Vertical reels, which feed the material horizontally into the rollformer, do not have material orientation problems. Vertical reels are usually passive to the line, which makes them immune to the high accelerations and line speeds on some of the faster lines. Acceleration and line speed are critical issues with pallet decoilers in rollforming applications. When applications required immediate acceleration, the best choice would be a vertical reel. When line speeds are very high, such as over 300 feet per minute (FPM), again, the best choice is the vertical reel. However, rollforming machine manufacturers are now producing lines with variable-speed drives. With these features, the pallet decoiler is a viable option. This type of rollformer can give the pallet decoiler sufficient time to accelerate up to speed.

Purchasing a Pallet Decoiler

When purchasing a pallet decoiler, the most important factors in assuring a successful project are:

1. Coil directions. The machine should run clockwise and counterclockwise without having to relocate the machine or relocate the control arm. This could save time because you cannot rely on coils always going in the same direction.
   
   
2. Construction. The basic machine design should be heavily constructed, with sealed bearings and a drive design which requires little or no maintenance. Friction drive systems will slip under certain conditions, causing misfeed problems and inadvertent line shutdown. The decoiler's design should be built to undertake the riggers of the high-production rates associated with rollforming lines. The machine should not limit your use. Also, as was discussed previously, you may want to use as large a coil diameter as possible. Make sure the decoiler platform is large enough to handle these coils with minimum or preferably no overhang. This will help assure safe operation.
   
   
3. Controls. The control system should be smooth, responsive and user-friendly. If the machine clogs or runs at uneven speeds, it will kink your light-gauge materials. The machine should come equipped with a safety shutoff system that will preferably shut down the whole line if the coils become tangled. Conclusion The process of handling coiled material is a basic part of a rollforming line. Often, however, it is overlooked as an area that can improve your rollforming line's efficiency. With the technical improvements of the modern rollforming system, you need to look at the efficiency of your coil handling method. With new lines that are going faster and producing more in the same space, the way the coil is handled and delivered is paramount.

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