Based on the study, the top technology priorities of warehouse managers are those that support changing value-added processes and unique warehouse workflows, followed by labor management, lightweight inventory control, slotting optimization, integrated dock and yard management and RFID.In broad strokes, the study points to three strategies that can provide warehouse managers with solutions to meeting ever-increasing customer requirements:
- New wireless-enabled technologies such as RFID and wireless networks to transform distribution processes.
- Rethinking how to integrate inbound vehicles, dock activity and yard management into traditional transportation and warehousing processes.
- Evaluating new ways to control product movements and improve velocity not just inside their distribution centers but also in drop yards, satellite facilities, and even at suppliers' warehouses.
One answer to the quest for new and better ways for storing and moving product in the warehouse has come from the academic community. Russell Meller, Ph.D, a professor of industrial engineering at the University of Arkansas and Kevin R. Gue, Ph.D., a professor at Auburn University have modeled a more efficient and productive rack layout for distribution centers.
In examining warehouse space and how it is used the two researchers asked if traditional ways of bringing pallets in and moving pallets out of present facilities are the best ways to speed the process of getting product to the customer. The quick answer is "no." For the unit-load warehouse Meller and Gue have devised several new designs that can lead to faster retrieval rates and significantly reduce costs for operating distribution centers.
"There are some classic works in our field of operations research and industrial engineering that have considered how to route workers within a warehouse to minimize the amount of time they spend traveling around the warehouse to gather picks and this sort of thing," says Gue. "We were considering some of this work and reflecting on it and it occurred to us in sort of a moment of inspiration that all of those works assumed that warehouses had to look like what we all see in warehouses today and so I think the first step was to ask, 'Why does it have to look like that?' And of course the answer was that it doesn't."
That insight led to the development of several mathematical and computer models. "Many companies now stress the speed with which they can get a shipment to the final customer," adds Meller. "The kinds of designs we're talking about definitely have the potential to reduce lead-time it takes to fill orders."
As they explain, in conventional warehouse designs a system of parallel picking aisles are sometimes connected by one or more cross aisles. Within this configuration, the unquestioned design assumptions are: that cross aisles are straight and must meet picking aisles only at right angles; and that picking aisles are straight and oriented in the same direction. The two alternatives designed have lower overall density of storage space but improve order-picking response times.
The first alternative is one the researchers call the "optimal cross aisle" design, which inserts two diagonal cross aisles that originate at the same pickup and deposit point. The cross aisles form a "V" in approximately a half of the total space occupied by picking aisles and rack rows. In their simulations, Meller and Gue determined that this design reduced picking costs by 11% when compared to traditional designs. "The Vshaped aisle in the proposed design," notes Gue, "is not something we just thought up, but is the output of an optimization model that seeks the best cross aisle possible."
The V-shaped diagonal cross aisles are retained in the second alternative design in which the researchers added vertical picking aisles. Calling this model " fishbone aisles," horizontal rows of picking aisles occupy the two sections outside the diagonal, V-shaped cross rows.
"In looking at the fishbone," explains Dr. Meller, "the bottom aisle is replaced by a diagonal aisle going up through it, so all of the flow is on one aisle. In the optimal cross aisle some picks will actually go along the bottom and then up to the picking point where others will travel along the diagonal cross aisle. The Fishbone confers more advantages in terms of reducing travel distance. We're comfortable saying that although the Fishbone design may not be the best possible, it garners nearly all of the possible improvements." The models indicate that a 20% reduction in travel times is possible.
"When we say 20%, we're not talking about 20% of total labor cost. Our 20% benefit applies to the amount of time spent traveling in the warehouse," Gue cautions. "It's easy for someone to imply we mean they're going to be able to cut the labor force and reassign every fifth worker. That would be true only if workers spent all of their time traveling, which they don't."
The researchers have applied for a patent on the designs. They have received so many inquiries that Gue has posted answers to some of the most common questions on his own blog (http://whaisles.blogspot.com).
To ship 2,000 metal items weighing up to 777,000 pounds each day requires sturdy, reliable lift trucks. For Doug Jones, facilities manager for the 500,000 sq.-ft. Southington, Conn., headquarters of Yarde Metals Inc. (www.yarde.com), dependability is key. Jones is responsible for all equipment maintenance. "The majority of our equipment is Toyota. We have about 68 of their propane forklifts in this facility," he reports.
There are seven Yarde Metals service centers outside of Connecticut and several international branches that serve as shipping and processing centers. The company's inventory includes aluminum, stainless, carbon steel, brass and copper products. "We distribute bar stock, sheet stock and plate," Jones explains. "We saw cut, shear and plasma cut as well."
In addition to Toyota lift trucks (www.toyotaforklift.com), Yarde uses some electric side loaders from Raymond (www.raymondcorp.com) and Combilift (www.combilift.com) for specialized handling of marine alloy sheets, which can measure 8 feet wide by 30 feet long.
Yarde stacks to 12 feet and racks reach as high as 26 feet. Material handling operations are fairly straightforward, moving palletized or bundled metal from trucks to rack locations. Running 24 hours a day, five days a week, makes preventive maintenance critical.
"From this location we control all of the equipment used at all of our branches," Jones notes. "We do all of our own maintenance here, in the main facility. At the branches we call people in from the outside for maintenance. The Toyota trucks are very dependable and easy to work on. We have two or three different models of their trucks, typically in the 8,000- and 10,000-pound range. When there's warranty work, we let the Toyota dealer come in and service the trucks."
Rather than lease, Yarde Metals purchases its material handling equipment. Jones estimates the company averages five years of service on its lift trucks.
Tried and true material movement and some new thinking combine to keep the supply chain supple.
Innovative rack layout designs from researchers at University of Arkansas and Auburn University.
Optimal Cross Aisle
New Lift Truck Roundup
Electric trucks feature intuitive controls
The 4700 Series AC-powered lift trucks from Raymond.
Simple to learn and operate, Raymond's (www.raymondcorp.com) new 4700 Series fourwheel, sit-down ACpowered electric lift trucks offer operators a roomy compartment to sit in and intuitive, ergonomic controls for running the machine. The unique steering system design delivers a tight turning radius for fast right angle stacking. ACR System for both lift and drive uses less energy, saving on batteries, chargers and downtime. The 4700 Series is available in a wide variety of capacities, ranging from 3,000 to 6,000 pounds, and in 36- or 48-volt configurations.
Walkie stackers maximize efficiency
Toyota's 7-Series walkie.
To maximize battery and operator efficiency, the 7-Series of electric walkie straddle stacker lift trucks from Toyota Material Handling, U.S.A. (www.toyotaforklift.com) employ "separately excited" (SepEx) drive motor technology and a metal oxide semiconductor field effect transistor (MOSFET) controller. Together they work to offer excellent acceleration and top travel speed whether the truck is loaded or unloaded. Available in 2,000- and 2,500-pound capacity models, the lift trucks use a 24-volt electrical system and offer interlocking mast channel construction and a spring-loaded control handle that automatically applies the parking brake when the handle is released.
Turret stockpicker wins design award
Crown's TSP 600- works in very narrow aisles.
Multi-task controls that merge multiple load handling tasks simultaneously save positioning time for operators. The TSP 6000 Turret Stockpicker from Crown Equipment Corp. (www.crown.com) does just that. The main mast can raise and lower while the auxiliary mast raises and lowers, or pivots and traverses, while the truck is moving.
Winning a Silver IDEA Award from the Industrial Designers Society of America, the TSP 6000 can transport, store and pick palletized goods in very narrow aisle environments. Its auxiliary mast can traverse and pivot automatically to keep pallets evenly centered between warehouse racks. The truck's MoveControl seat swivels to four different positions to provide maximum flexibility and operator comfort.
Reach trucks have tipover protection
Jungheinrich offers the ETV Series 1 for stacking to high lift heights in confined space.
All models in the ETV Series 1 of mast moving reach trucks have Curve Control, a feature that limits travel speed and acceleration during cornering to help reduce tipover risks. Offered by Jungheinrich Lift Truck Corp. (www.jungheinrich-us.com), all of these trucks employ a proprietary 3-phase AC technology to power travel, lift and steering motors.
There are four models in the ETV line. For aisles as narrow as 105 inches, Models ETV 110 and 112 have a 44-inch wide chassis with load ratings of 2,000- and 2,400-pounds. Models ETV 114 and 116 offer an outer chassis width of 50-inches, and can handle loads up to 2,800 and 3,200 pounds respectively.
Three-wheel, AC-powered trucks navigate tight aisles
Mitsubishi's new forklift series features interchangeable components.
Offered in three models with capacities ranging from 3,000- to 4,500-pounds, the FB16NTFB20NT Series of NGeneration three-wheel electronic forklift trucks from Mitsubishi Forklift Trucks, (www.mitlift.com) are entirely ACpowered. N-Generation offers a control system with modifiable performance setting to control top travel speed, lifting speed, regenerative braking and auto regenerative braking. The AC drive system employs innovative heat dissipation technology to deliver maximum performance while reducing battery consumption.
Three-wheel design and hydrostatic steering deliver increased maneuverability to navigate areas with tight aisles. Torque and speed are controlled separately to maximize driving performance.