The dock is the conduit all inventory must pass through. It is the physical connection with the outside world, yet dock operations can be one of the most neglected areas of a facility when companies modernize their warehouse operations. The dock area can also be one of the most labor-intensive and hazardous areas. In that regard, dock operations are ripe for careful analysis and use of the most effective material handling solutions available in the market today.
Common to all dock operations is the need for speed and efficiency as both shippers and carriers need to have product on the road heading for the next destination. Trailers must be loaded and unloaded quickly and product sequenced in a "last in, first out" fashion. These operations can be very labor-intensive as pallets stacked with parcels are brought into trailers on pallet trucks or forklifts and then items manually removed from pallets and stacked on the trailer floor. Likewise, unloading operations can be equally manpower-intensive as parcels have to be stacked on pallets and shuttled out of trailers with pallet trucks or forklifts to be inducted into the warehouse. In short, dock operations can be the bottleneck if not properly addressed.
Loading and unloading operations in the warehouse dock area have always been among the most hazardous areas in the distribution center (DC). There is often movement of packages in and out of trailers with hand trucks or forklifts. Operators encounter ramp bridges, and lighting is generally poor inside trailers. A very dangerous scenario is trailer creep which can result in forklift accidents, potentially causing serious injury to operators and devastating damage to equipment. Using automation equipment during the loading and unloading process can reduce worker's compensation claims and increase employee safety because of improved ergonomics.
The scale of dock operations ranges from small firms handling 30-60 packages per day to large e-commerce retailers and major parcel carriers processing 10,000+ packages daily while operating on a 24/7 basis. Some operations emphasize cross-dock operations while others receive and stow inventory to meet future customer demands. Seasonal fluctuations can result in mixed distribution strategies, driving the need for adaptable equipment and processes.
Many DCs are now engaged in both e-commerce fulfillments directly to customers as well as store replenishment on a daily basis. Accuracy, speed, flexibility and minimal man hours remain key metrics in designing any dock operations modernization plan. Improving ergonomics will reduce employee injury and increase productivity. Safety is always paramount.
Minimizing Handling
Let's first consider small retailers and manufacturing shops not possessing the space or the throughput justification for comprehensive systems yet desire to take advantage of off-the-shelf equipment enhancing their material flow. Many of these smaller firms don't have loading docks with dock wells, which means they must contend with trailers four feet off the ground. The hazard to warehouse personnel transferring packages in and out of the trailer is significant.
One potential solution for this challenge is a dockless receiving system. The core components include 10-foot rigid conveyors with adjustable legs coupled with a flexible gravity conveyor and a swing stick extension.
A dockless receiving system utilizes the swing stick extension to bridge the gap between the flexible gravity conveyor and the bed of the trailer.
Depending on the length of the trailer, two or three 10' extensions are placed in the bed of the trailer and attached to the swing stick. The employee stands in the bed of the trailer and picks packages to load onto the dockless receiving system.
"Previously, employees would roll a conveyor out to the bed of the trailer and unload it using a two-step process," explains Kurt Huelsman, president of FMH Conveyors. "Now with a dockless receiving system, [they can] move more product with less effort in a shorter amount of time."
In one recent case, a retailer was able to reduce unloading time from an average of 2½ hours to 45 minutes using the dockless receiving system.
For larger DCs where rapid throughput is essential, hand moving packages in and out of trailers must be minimized. It is time-consuming and ergonomically difficult for employees and accuracy can diminish. Forklifts traveling in and out of trailers are a potential hazard to operators and those packers inside trailers and they're less efficient in utilizing the cube of the trailer.
Automated equipment can keep packages moving between the warehouse and the shipping & receiving area, resulting in adherence to the age-old rule, "Only handle it once."
One solution increasingly seen in modern, high-volume DCs is the telescopic conveyor. Telescopic conveyors extend the powered conveying surface inside the trailer. These conveyors eliminate the need for forklift and pallet truck movement in trailers by bringing the product into the trailer at the location where it is to be loaded.
Telescopic conveyors are mounted on the loading dock floor and telescope into the trailer without any contact with the trailer floor, thereby negating any floor obstacles. Nor do they need to be steered as with rigid drive-out or gravity systems. As a trailer is being loaded or unloaded, the powered conveying surface is extended or retracted until the trailer is full or empty.
Handling is minimized as product no longer needs to be transferred from the warehouse conveyor system to a pallet truck or forklift for loading or unloading. Packages stay on the conveyor system to the point where they are stacked in the trailer. Pick-to-ship is one continuous flow, with direct interface to sortation and shipping systems. Likewise for unloading operations, product is loaded directly onto the telescopic conveyor and inducted directly onto the warehouse conveyor system for processing and storage.
Several firms manufacture telescopic loading/unloading dock conveyors. Mark Hogan, vice president of operations with FMH Conveyors, notes several advantages realized with telescopic autoloader operations. "With a telescopic conveyor, the customer's products get where they need to go every time.
Compared to other belted solutions such as the rigid drive-out, the telescopic conveyor consumes the least amount of valuable dock real estate, requires minimal operator control, does not make contact with the dock plate or trailer floor, and its design permits the addition of a number of ergonomic features such as hydraulic tilt, snout and man-rider platform."
One option to maximize the benefits of telescopic conveyors without large capital outlays is a traversing mechanism mounted on the conveyor. A DC may have several docks yet not have the volume to justify telescopic conveyors for each dock door. Once a trailer has been loaded/unloaded, the telescopic conveyor is traversed by electric motor along an unobtrusive track to another dock door where trailer loading/unloading is required. There is little idle time for the system. Use of the telescopic is optimized when it is moved to the next trailer available for loading/unloading while the previous trailer awaits departure.
In sync with the trend towards "lights out" fully automated DCs, telescopic conveyors can also be equipped with an autoloader package, a programmable sensor package that can optimize trailer loading. Some users have achieved an 80% to 95% cube utilization rate based on product size and package type.
"With this lights-out approach, e-commerce retailers have gained efficiencies in their dock operations through the use of autoloaders in their shipping operations," Hogan points out. "The individual orders are quickly loaded in the contracted parcel carrier's trailer, such as USPS, FedEx or UPS, and transported to the carrier's DC for sortation and shipment to the retail customer."
Cost savings realization is a major factor when considering any investment in new equipment. With telescopic conveyors, loading and unloading operations are faster, resulting in less time each trailer must remain at the dock. This ultimately results in the need for fewer dock doors and associated equipment such as dock levelers, dock locks and sensors. Forklift operator costs are reduced as fewer forklifts are required for loading and unloading operations.
Cost savings result from safer dock operations, with reduced chance of injury to humans and damage to dock equipment. Finally, operations are seamless with less handling of the packages, minimal interruptions, and a reduction in dock personnel.
In conclusion, available systems offer efficient solutions for a range of companies engaged in dock operations. Whether it's a small retail store or a large e-commerce retailer, all can reduce man-hours and increase efficiency while reducing the hazards associated with dock operations. What then is the next frontier for dock operations? For the larger players in the distribution field, it's fully automated, lights-out loading and unloading systems operating on a 24/7 basis. Call it the warehouse version of self-driving cars.
Alan Will is president of PWG Distribution Solutions LLC, specializing in analysis of logistics requirements for small and medium-sized firms. A retired Marine Colonel, logistics specialist, he is also a member of MH&L's Editorial Advisory Board.
