By Thomas R. Cutler
Warehouse management systems must deliver efficient and lean material distribution operation systems through unrivaled personnel, inventory, and equipment management. Few warehouses experience 99.9% inventory accuracy and up to 35% productivity improvement from an automation environment.
According to Mark Stevenson, “Warehouse Management Systems must link the logistic environment and the equipment available in the warehouse and consists of two main modules.” Stevenson is Vice President for Egemin Automation, Inc., a global provider of Automatic Guided Vehicle Systems, Material Handling and Automation solutions. For the past twenty years, Stevenson has worked with many of the world's largest corporations on the design and implementation of automatic guided vehicle systems, including two of the first automatic trailer loading system in the United States, and he holds a patent as a co-inventor of ATL technology. Stevenson is recognized as one of the foremost authorities and subject matter experts on the design and application of automated trailer loading systems and warehousing automation with automatic guided vehicles. “Warehouse Management Systems must be specifically designed to work with all forms of automation, as well as forklift truck fleets,” noted Stevenson.
Core Inventory Management
An inventory management module must store product according to the carrier and compartment number, product attributes (owner, lot, quality, abc qualification), storage zone, etc. Cross-docking operations move products of a specific customer from reception directly to dispatch. Warehouse management systems must allocate warehouse inventory to order lines based on intelligent allocation algorithms: least remaining stock per carrier, FIFO, FEFO, capacity distribution and optimization. Orders must be automatically reallocated to another carrier in case of unexpected product shortages.
Order Management
A warehouse order management modules must assign orders to resources based on priority, due-out time and order reception time. The WMS solutions must support order-picking concepts such as single order picking, batch picking and cluster picking. Optimization algorithms must be implemented for these concepts to fine-tune the product flows
Warehouse storage applications with AGVs
Examples of automatic storage applications with AGVs include:
Block storage of pallets, containers, racks, boxes and tubs
Pallet storage in warehouse racks
Vertical storage of reels
Horizontal storage of reels in cradles
Automated guided vehicles control the full receiving process of raw materials from trailer to processing lines. They make sure goods are delivered in time without stalling the production process.
Specific applications in receiving areas include:
Automatic trailer unloading
Raw material transport to intermediate storage
Direct supply of raw materials to production lines
Automated guided vehicles are the ideal transport solution from end-of-line equipment to shipping in distribution centers. All of the benefits of AGV’s are only realize when the WMS solutions are comprehensive and allow for add-on elements such as a track and tracing module, statistical KPI management reporting, trailer patterning, yard management, equipment alarm management, warehouse control systems, and satellite storage.
Stevenson suggests that, “Warehouse Control Systems integrate all automated equipment in a warehouse into one well-oiled and efficient transport system.” Supported storage methods must be fully compatible with all standard storage methods such as pallet racks, mini-loads, block stacking or drive-in racks, but also support more complex methods like satellite storage, double deep storage, roll-through racks and paternoster systems. “The entire transport assignment should be split in several smaller track segments per transport means (such as conveyors, shuttles, cranes, forklift trucks, and AGV’s) and should control each sub-transport fully autonomously.”
Warehouse Control Systems allow for optimal usage of the available transport means and storage methods. Each warehouse installation is exploited to the fullest, all loads are equally spread among the available transport means and overload problems are avoided as much as possible. WCS solutions integrate the following functions:
Controlling the flow of material of individual carriers: pallets, trays, bins and boxes.
Managing open transport assignments from start to finish.
In complex warehouse installations (several large storage zones and / or various working zones), an effective WCS will take care of a balanced and continuous supply of carriers to all working stations, avoiding saturations of a logistic system.