General Mills goes vertical to optimize space

Even the best-laid plans are subject to change, especially when it comes to manufacturing and distribution. That was the case at General Mills’ Cedar Rapids, Iowa, plant. The plant had successfully used pallet flow and pushback rack systems, but ongoing growth, product changes and long use required a storage system update that would safely add capacity to their existing facility.

As one of the world’s largest food companies, with global net sales of $17.8 billion in fiscal year 2013, General Mills operates more than 100 consumer brands in more than 100 countries and markets, including Cheerios, Häagen-Dazs, Nature Valley, Betty Crocker, Pillsbury, Green Giant, Old El Paso, Yoplait and more. The food manufacturer values innovation in every aspect of its business, including storage and logistics.

The plant’s previous pallet flow and pushback rack systems had served almost 15 years. During that time, however, volumes grew and pallets became heavier. Wherever possible, the plant switched from 50-pound bags of ingredients to 2,500-pound bulk super sacks to enhance efficiency and minimize materials handling, according to Scott Ladwig, an inventory analyst at the plant. Although the facility was bursting at the seams, expansion was not an option. And, General Mills did not want to use outside storage or maintain material in trailers until needed. Instead, it wanted to find ways to store more raw materials and product in its existing space.

“The challenge was to make better use of our existing vertical warehouse space, since adding to our building was not an option,” says Ladwig, who sought to avoid trailers of inventory sitting in the yard or contracted third-party storage. “We wanted to safely optimize our storage, inventory and production.”
The solution was a new integrated pallet flow storage and pushback rack system (Steel King, steelking.com).

In a flow storage system, dynamic flow rails are inclined in a static rack structure: In this system, loads placed on one end of the rack system move by gravity on rollers to the unloading end, with speed controllers acting as gentle brakes. When one pallet load is removed, the pallets behind it automatically move forward.

Since the flow system depth, height and width were limited by the size of the facility and capabilities of the materials handling equipment, it was a good fit for the plant’s high-volume, space-efficient needs. Once loaded, first-in/first-out (FIFO) product rotation is automatic and the rack eliminates labor and fork truck operation to arrange loads. Forklifts are required only for the initial and final unloading. Since only two aisles are necessary, aisle space can be reduced by 75% and up to 100% more product can be stored than with traditional selective pallet racking.

The solution also used pushback pallet rack, which offers up to 90% more product storage than selective rack systems and up to 400% more selectivity than drive-in racks. Unlike single-deep pallet rack, a dynamic pushback rack system allows the storage of pallets two to five deep while providing easy access to a variety of different SKUs. Pallets are stored behind each other in a series of nested carts and are loaded from the same side of the system, eliminating separate aisles for each function. Composed of a stable rack along with a series of inclined carts and rails, when one pallet is pulled, the one behind it rolls forward.

To optimize the system, General Mills consolidated the flow storage and pushback rack into an integrated system, and turned them both 90 degrees to free up floor space for corrugate storage. This approach enhanced the flow of product and packaging materials to the production line, and it allowed high-density storage and flow from end to end.

“Integrating the two separate racks into one rack system increased storage capacity by 42% and freed up space, allowing the addition of 24% more inventory items,” Ladwig says. “It eliminated any issue of trailers of inventory sitting in the yard and the potential need for contracted third-party storage space.”

To enhance rack longevity, the General Mills plant chose rack that features a bolted beam connection to structural channel columns. A number of rack features helped the company meet its strength, durability and maintenance goals. Compared to typical racking, the pallet rack, constructed of hot-rolled structural channel column with full horizontal-diagonal bracing, offers greater frame strength, durability and cross-sectional area. The use of all grade-5 hardware provides greater shear strength, and a heavy 7-gauge wrap-around connector plate ensures a square and plumb installation with a tighter connection and greater moment resistance.

Special column punching in the structural rack provided 2 inches of adjustability to better accommodate the dimensions of super sacks and larger pallet sizes. “We needed to adjust to larger pallet capacities now and into the future,” says Ladwig. “Simply raising or lowering our rack levels allows us to meet both current and future pallet sizes.”

To enhance rack safety and longevity, General Mills’ supplier conducted a safety audit of the plant and added a number of safety features to the rack and flow lanes.

As an example, the old rack system suffered structural damage in the past when fork truck operators stacked product alongside the racking. For added protection against such fork truck impact in the new system, pre-fabricated modular protective railing was installed. The guard rails protect the sides of the rack from fork truck traffic, as well as give them a “backstop” to place packaging up against one of their lay down areas.

In the plant’s new pallet flow and pushback rack system, rack bays were widened to better accommodate new product weights and dimensions. The wider rack bays also allowed for a larger “flue” along the upright runs for sprinkler dispersion, which helped to win approval of the design from General Mills’ insurance company.

Pallet flow entry guides were installed to improve pallet flow in the flow lanes and allow more forgiving pallet placement. Along with this, heavy gauge pallet flow rollers were placed in the entry and exit flow lanes to better withstand pallet impact. Reinforced rail side channels were also used to hold the pallet flow rollers in place, and the rail channels were placed on thick structural angle for greater durability.

Perhaps most unique to the project, to prevent accidental overloading of the pallet flow rack, an anti-backup “pawl” system restricts any pallet from entry if the rack is already at capacity. “The ‘pawl’ system prevents pallets from being unintentionally pushed out the delivery side of the flow rack and is designed with individual flippers that flip up to catch any size pallet,” says Ladwig.

“With our new integrated pallet flow and pushback rack system, our General Mills plant is operating more safely and efficiently than ever,” Ladwig adds. “We’re ready for continued growth for the next 15 years and beyond.”