By Len DeWeerdt and Matthew Houck
SAN FRANCISCO,
Sept. 30, 2007
(Viewpoint) -
Picture a game of Jenga with its wooden blocks stacked criss-cross to form a tower that begins as a fairly stable structure. However, as pieces are moved, rearranged and stacked on top, the tower becomes increasingly unstable. Then, change the setting from the kitchen table to the floor of the mill warehouse, where rolls of paper are stacked on top of each other and there is much more at stake. A shipment needs to leave now, and the item that is holding it up is in the middle of a stack of rolls. Can it be retrieved in time? Will the stack tumble?
Storage and retrieval is certainly not a game for the paper industry, but it is something that every mill must play. The strategy here can bring great returns in the areas of damage reduction, output planning and the amount of lineal feet that can be managed in-house. It also has the potential to reflect positively through the entire supply chain by positioning a company as being efficient, accurate and timely.
Stacking rolls on end has obvious appeal because of the low overhead cost involved. In essence, all that is needed is floor space and faith in the clamp truck drivers' ability to pick orders without creating a domino effect. Stacked end-on-end with multiple client specific rolls intermixed, shipment retrieval primarily hinges on the ability to access what is needed in the timeframe required to meet customer requirements. Another concern is product damage, both from handling and warehouse deficiencies, and the ability to get the roll from storage to shipment without harm to the paper. When problems occur in this process, they can be very expensive in terms of product damage, order fulfillment and potential injury.
Activ Systems, licensed in the US by Retrotech Inc of Fishers, NY, offers a way to store paper rolls by creating a high density flow-through process. The system can actually store rolls in three ways: on the bilge directly; on the bilge in a custom, nested trolley; or on end with platforms or skids. In addition, rolls can be stored in the same system, mixed with palletized cases, as long as the loads share a uniform and consistent width.
This storage system is not an automated storage and retrieval system (AS/RS) of cranes (storage retrieval machines or SRMs) and aisles, but is a densely populated set of racks with a vertical lift that can reach 100 ft high and horizontally move multiple loads at a speed of 500 fpm simultaneously. It uses a rack system with rails, carts, vertical transfer lifts (VTL) and cross-aisle transfers (CAT), all of which are controlled by intelligent software. Its software is constantly solving route algorithms to achieve the most efficient and rapid movement of loads through the system to improve the accuracy of orders and the speed in which they are filled.
Perhaps its biggest benefit is how this rack storage system is always specifically crafted from the design phase and throughout the execution of the system to ensure that the desired outcomes are being met for the paper company and the end customer. That custom design applies to both the racks and rails that comprise the system, as well as the software driving it. The structure is modular and the software that controls it is flexible, allowing the system to easily adapt as business evolves.
High Density Storage
Storage density is important when a building footprint is limited, whether economically or geographically. While stacking rolls on top of one another restricts how high you are able to stack, an Activ system can turn previously wasted ceiling space into a storage area. By using more cubes in the same floor plan, the amount of lineal feet of paper that is stored can increase without having to expand the existing structure.
With Activ's high density flow-through systems, thousands of pallets or rolls with multiple SKUs may be loaded into a system at any given time. The loads are scanned and processed as they enter the system, and the system's software keeps track of the load position as it is relocated. The capabilities of the system allow for roll sizes up to nearly 7 ft in diameter, and 6.5 ft in width. Storing on the bilge directly allows for rolls of different lengths to be stored back-to-back.
The rack storage system's input points consist of a short input conveyor, a roll sizing station and a bar code reader. The system receives input directly from in-floor on-the-bilge roll conveyors. As the rolls move toward the VTL, they are scanned and size-checked to validate the roll dimensions and to reconcile the roll with the host as a valid input. Acceptable loads continue into the system, while unacceptable loads are routed to a reject spur for rework and return to the system.
Loads exit the system through vertical lifts and move out to conveyors in the processing areas. Rolls move to the process areas as requested by time and priority. The system's software is constantly managing the output requests, determining how best to move rolls from their storage location to the desired output in the required time frame.
Without any direct human/roll interaction, any of the potentially hundreds or thousands of rolls loaded into a system can be brought out on demand in the course of a day. Contention for paths and required equipment are managed automatically by the system's software, which is constantly evaluating the inventory as rolls are output and new requests are being made. Unlike stacker cranes (SRM or AS/RS), the rack storage system can receive and deliver rolls to points around the entire periphery of the rack structure.
The value of the system is working with the software engineers directly to ensure that the product moves as needed rather than designing workflow around pre-existing software. This could be something along the lines of dividing fast moving products from the slow movers, ensuring that the system sticks to a strict first-in/first-out policy or any other custom process required at the mill.
Roll Damage Reduction
Paper mills spend millions of dollars on research to raise product quality, but they also lose millions through the mishandling of paper rolls. With oversupply fueling customer's demands for zero-fault deliveries, damage prevention in the supply chain is becoming more than a mere cost-cutting measure. Today's paper rolls are made to accommodate customer requirements, which are unique in terms of length, surface weight, quality, running properties, etc. Damage to these rolls, therefore, can have costly consequences.
Hundreds of rolls may be spoiled by one defective clamp truck before the problem is even noticed. With this in mind, many mills have made minimizing the number of times a roll is handled by clamp trucks a high priority. Eliminating the direct handling of loads during any link of the supply chain significantly reduces the risk for damage. With an Activ system, rolls can be moved from slitting to sorting and finally staging without any manual handling. Between stages, the rolls are "stored" within the aisles of the system and called upon on demand, which makes the system function quite similar to a slow conveyor that can accumulate (buffer), sort and stage rolls for shipment. In many applications, the reduced need for direct handling will also result in reduced requirements for personnel, clamp trucks and other related equipment.
Stora Enso currently uses Activ technology as work in process for roll handling at its folding boxboard mill in Fors, Sweden. The 10,000 ft2 facility is fully automated and features 3,000 storage positions that can handle paper rolls of various weights and sizes. More than 4,000 yards of storage lanes are capable of handling rolls up to 6.88 ft in diameter, 8.53 ft in width, and weights up to 5.5 tons. The ability to manage multiple sizes in one high density system allows Stora Enso to maximize the number of linear feet to pass through a single building, making the most of the building's existing footprint.
Output Planning with Customized Software
Unfortunately, many companies only consider supply chain improvements when inventory levels, customer complaints or late shipments are impacting financial performance. If competitors are approaching six sigma performance on key measures of customer-perceived value, it may be too late. If not, an organization may be in a position to emulate the success of companies that are achieving profitable revenue growth by gathering customer requirements and making supply chain changes that create, communicate and deliver superior customer value. Research findings from a book titled Strategic Supply Chain Management indicate that companies with an "exceptional order fulfillment processes overall are more than 20% more profitable than average companies and are growing their top-line sales 25% faster."
By using the rack system to store rolls, a mill can prepare for a shipment by letting the system's software pick, buffer and sequence the output in any order. Here, the benefit goes well beyond storage and retrieval and is passed all the way down the supply chain.
The customized software is able to locate any load in real-time, identify its attributes and match it to orders in hand. Those loads route to the right dock, palletizer or conveyor in the appropriate sequence, and are then ready to be loaded when the truck arrives. This creates a smooth transition from storage to loading dock and eases the tension of any watch-tapping driver.
Can Automation Be Cost Effective?
One of the most common objections to any automation investment is the fear that business practices or customer needs will eventually change, making the current workflow obsolete. Activ's modular design of equipment and information single axis system components allow for a straightforward integration path that can be easily adapted to workflow changes. Input and output points may be placed anywhere on the system's periphery or at points internal, above or below the layout.
Another common objection is difficulty in achieving a return on the initial investment of the system. In truth, the system may actually aid in cutting costs by reducing inventory, maximizing existing space and significantly reducing product damage. It can also be configured to fit into existing facilities and linked to facility operations, in many cases without the need for major building alterations. This modular design characteristic combined with the high density buffering capability makes this rack storage system well suited for consolidation of outside distribution into an existing building. Without a need for fork or clamp truck aisles, or even extensive lanes for a typical AS/RS crane, the density of Activ means that the available space is maximized for moving product.
As paper manufacturers continue to look at how to more closely tie the orders received to the shipments needed, while still managing the need to make large runs as a means of leveraging manufacturing costs, a rack storage system offers a new approach for managing inventory. Being able to handle a variety of roll sizes and diameters, stored directly on the bilge, with lots of capacity for storing, sorting and retrieving rolls and meeting shipping processes, without the use of high cost mill labor, can make a return on the investment possible.
Len DeWeerdt is vice president of business development for Retrotech Inc, in Victor, NY. Matthew Houck is a public relations specialist for The Raytec Group in Fishers, NY.
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