New DC systems cut loadout time

Jack Mans, Plant Operations Editor

January 29, 2014

7 Min Read
New DC systems cut loadout time

In one way, Smith's Dairy, Orrville, OH, is like a lot of old-time, family-owned dairies in North America. It is closing in on the century mark in age, and it has enjoyed tremendous growth at the expense of efficiency. In another way, it is unlike most dairies, because its production facility and its cold room are on opposite sides of town, a couple of miles apart.

When Smith's plant manager Karl Kelby contacted Richard Dauphin, vp of American Conveyor (, he explained that the dairy was searching for a more efficient way to load trucks and decrease the time required for loadout.

"There was more than the distance factor that made this a challenging application that not just any manufacturer could take on," says Smith's project manager Dean Reed. "We were manually loading trucks at our production facility and then manually unloading them at the cross-town cold-storage facility, where our hybrid product-handling system included an aging crane and three levels of storage that were more than maxed out. We knew that the vendor we chose would need to work with a half-dozen third-party vendors, including two software companies, an electrical contractor, an independent building consultant and our team, which included company president Steve Schmid, vp of production Eddie Steiner, Kelby, engineering and maintenance supervisor Dave Baumgartner, warehouse manager John Dodds and myself, acting as project manager. The vendor would also have to integrate equipment like the palletizer and the bossy-cart (or milk cart) accumulation system that was not manufactured by them, into the overall system. Then, they would need to agree to be held responsible for the overall system's performance, and American Conveyor did just that."

Dauphin says, "We are used to solving unusual problems for both large and small dairies; that's what we do. But the logistics here made this a challenging project. By the time the project was finished, Smith's expanded its cooler by 35,000 square feet, and we designed, built and installed three unitizers, four de-unitizers and more than 5,000 feet of conveyor, which we seamlessly integrated with a palletizer and a bossy-cart accumulation system from third-party manufacturers. Seamless integration was important, as the performance warranty for the entire system was on our shoulders." The unitizer is a machine that combines stacks of plastic cases containing product into groups of stacks called blocks. This is done so that clamp trucks can handle more than one stack at a time. At Smith's, stacks that are typically six cases high are unitized into blocks containing nine stacks.

American Conveyor assigned sales engineer Steve Winning to the project, and Smith's accepted his 29th design, which included converting its manual-loading operations at the production facility into a unitizing operation, where cased products, including fluid milk and specialty products, are unitized, scanned and loaded by clamp trucks onto trailers for transfer to the cold-storage facility across town. American Conveyor also designed and installed two separate systems at the cold-storage facility. One receives stacked product from the production facility, and a second handles picking and loadout. The total project cost more than $3 million.

After unloading at the cold-storage facility by clamp trucks, the cased products are scanned and then put into short-term floor storage in the new cooler, either in nine-stack blocks or on 16 high-volume accumulation conveyors for order picking. The accumulation conveyors are fed from two of the new automatic de-unitizers. When inventory-control software determines that replenishment of a picking lane is required, the system sends a signal to the clamp-truck operator to deliver a particular product from floor storage to the designated de-unitizer. After the operator places the product on the de-unitizer infeed, he scans in the block, and the control system sets all the divert gates on the conveyors, so stacks are directed to the assigned lane.

Lower-volume products received at the cold-storage facility are fed into a de-unitizer that automatically converts the blocks into a single file of stacks and moves them onto a conveyor, where the product count and bar code are input by the clamp-truck operator. The product count is verified by a sensor on the conveyor, and the control system tracks the product to a divert point. The lowest-volume product is re-verified, recounted and then sent to the floor-storage area. Medium-volume product, after being re-verified and recounted, is sent to a palletizer, which places it on captive pallets that are introduced into one of two pallet lanes feeding the crane for storage in the high-rise pallet-storage system.

P roduct is automatically loaded onto bossy carts at the production facility, after which the carts are loaded onto trucks and delivered to the new cooler for storage and loadout. The carts are manually received and either stored on the floor or placed into one of 10 automatic cart-accumulation storage lanes. These lanes move the carts forward to the loading dock for picking an order. After an order is picked, the operator pushes a button to release one cart for loading on a truck. The system then automatically moves the remaining carts forward to keep product available to the operator. This greatly reduces the distance the operator has to walk and has been a major element in reducing loadout time.

The order-picking system is a separate system, independent of the incoming-product handling system, thus allowing simultaneous operation without risk of mixing products. There are four distinct picking operations: a low-volume, floor-stored pick area; two medium-volume, pallet-stored pick areas; and the high-volume, lane-stored pick area. Each picking area has a stack-accumulation conveyor at its discharge that allows the pick operators to pre-stage product on a track that comes to a common merge point for the order checker to merge, check and release the orders to the loadout.

The high-volume picking operation, which consists of the sixteen storage lanes previously mentioned, is an addition to the operation.These lanes end adjacent to a picking conveyor. The stacks are faced up to the picking conveyor, with the end stack accessible to the pick-platform operator. When the operator pulls that stack onto the picking conveyor, another stack is automatically advanced to take its place, allowing the operator to rapidly pick orders. Up to 16 products are available to the picker in a space of only 35 ft.

Once the orders are picked and come to the order checker, the various components of the order are merged and sent to one of two order-staging conveyors. Each conveyor can hold a complete trailer load of product, and the system is designed for a third staging conveyor to be added in the future. The staged product then comes to a three-way merge/divert point, where the load-out operator can select the track that delivers the order to the appropriate truck. This allows Smith's to load as many as three trailers simultaneously. Before the new system was installed, only one trailer could be loaded at a time.

All conveyor drives and devices are controlled by a single Allen-Bradley programmable-logic controller from Rockwell Automation (, which was provided by American Conveyor. The system was integrated with the existing warehouse-management system from HighJump Software ( The integration allows Smith's to have the product automatically directed to the appropriate storage system, to keep track of product inventory and location, to manage the product orders and picking and to direct it to the appropriate truck for loadout. Communication between the HighJump software and the Allen Bradley programmable logic controller required the use of third-party software provided by Citect, Inc. (

Smith's Reed and American's Winning agree: "The same volume of product that took twent-seven hours before the installation of the new system now takes only sixteen hours."

More information is available:

American Conveyor Corp., 718/386-0480.

Citect, Inc., 770/521-7511.

HighJump Software, 952/947-4088.

Rockwell Automation, 414/382-2000.

About the Author(s)

Jack Mans

Plant Operations Editor

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