Warehousing Equipment

The role of equipment in warehouse operations Reduce cost (labor + space) enhance space utilization by, e.g., enabling the exploitation of the vertical dimension of the facility allowing for denser packing allow for more efficient operations by, e.g., increasing the sku density supporting the automated transfer of material from storage to sorting and consolidation area Enhance responsiveness increase the throughput of the facility, e.g., establishing a more ergonomic environment/arrangement for the warehouse operators facilitating the parallelization of order picking by parallelizing the tasks of order-picking and replensihment

The role of equipment in warehouse operations (cont.) Maintain Quality of Product and Operations provide an orderly storage environment provide efficient ways for product tracing and identification provide safe and secure material handling facilitate order sortation and consolidation establish and maintain a controlled environment e.g., temperature control access control

Equipment Classification (Tompkins et. al., pgs 170-173) Containers & Unitizing Equipment Storage and Retrieval Equipment Unit Load Small Load Conveyors Warehouse docks and dock-related equipment Automatic Identification and Communication Equipment

Pallet Storage Modes Block Stacking Rack Storage Single-Deep Double-Deep Drive-In/Through Pallet Flow Unit Load AS/RS etc.

Block Stacking (or Floor Storage) Lane Height Lane Depth (3-deep) Lanes An efficient storage mode when there are multiple pallets per SKU; inventory is turned in large increments, I.e., several loads of the same SKU are received or withdrawn at one time. Main problems: Loss of space due to “honeycombing” not effective utilization of the vertical dimension of the facility

Selective or Single-Deep or Simple Pallet Rack The “benchmark” storage mode Due to rack supports, each pallet is independently accessible (i.e. it supports totally random access) Trade-off: too many aisles => inefficient space utilization

Double-deep rack Two selective racks placed back-to-back => 2-deep lanes Each lane dedicated to one SKU => space loss in case of SKU’s with odd number of pallets Less aisle space required (upto 50% savings in aisle space) Trade-off: More work and/or specialized equipment for retrieving

Other pallet rack types Drive-In/Through rack: 5-10 loads deep Better space utilization More difficult, even dangerous retrieval Pallet flow rack: up to 8 pallets deep The rack shelves are slanted and have rollers, and therefore, every time a pallet is retrieved from a lane, the pallet behind it takes its position. Allows for simultaneous picking and restocking Supports FIFO operation Typically used in high-throughput facilities Cantilever rack: Supports long items like timber and pipes

Unit-Load Retrieval Equipment Key Differentiation factors: aisle width requirements lift height/weight capacity Lane depth they can reach degree of automation capital expense Major types Walkie Stacker Counterbalance Lift Truck Narrow Aisle Vehicles Automated Storage/Retrieval Machines

Small Load Storage and Retrieval Equipment Operator-to-Stock (or Man-to-Part or in-the-aisle) system: the operator travels to the storage location to retrieve material Stock-to-Operator (or Part-to-Man or end-of-aisle) system: the material is mechanically transported to the operator for retrieval Advantages of STO: higher productivity easier supervision better item security and protection Disadvantages of STO: more expensive more maintenance more difficult to reconfigure

Operator-to-Stock Storage Equipment Bin Shelving Modular Storage Drawers in Cabinets Carton Flow Racks Mobile Storage All the above equipment can also be arranged in mezzanines to get a better exploitation of the building cube.

Operator-to-Stock Retrieval Equipment Picking Cart Order Picker Truck (for higher placed loads) Person-aboard Automated Storage/Retrieval Machine captive aisle free roaming (Robotic Retrieval)

Stock-to-Operator Equipment Carousels Horizontal Vertical Independently Rotating Racks Miniload Automated Storage and Retrieval Machine Automatic Dispenser Productivity gains Allow for extensive parallelization of order retrievals Focus on extracting rather than traveling and searching

Conveyors (Flat) Belt Roller Telescoping Belt Chute Sorting Remarks: Deflector Push Diverter Pop-up Skewed Wheels Pop-up Roller Tilt tray Remarks: Conveyors change the economics of travel. They can partition physically the warehouse into zones

Warehouse docks and dock-related equipment Warehouse docks: The facility interface with the shipping carriers Dock configurations and dimensioning

Equipment facilitating the interfacing between docks and shipping carriers Dock levelers: compensate the height difference between the carrier platform and the dock door mobile yard ramps permanent adjustable dock boards truck levelers scissors-type lifting docks Bumper pads: absorb the shock from the impact of the shipping trailer with the dock walls (laminated rubber cushions) 40,000 lb load traveling 4 mph => 150,000 lb force Dock shelter: a flexible shield that when engaged to the carrier provides a closed-environment interface between it and the inner area of the warehouse energy savings, increased safety, product protection, etc.

Automatic Identification and Communication Equipment Permits real-time, nearly flawless data collection and communication, and therefore, it facilitates and increases the real-time awareness of the location, amount, origin, destination and schedule of the material.

Automatic Identification and Recognition Bar coding technology: bar codes bar code readers bar code printers Optical character recognition Radio Frequency (RF) and Surface Accoustical Wave (SAW) tags Magnetic Stripes Machine Vision

Automatic Paperless Communication RF data terminal Voice headset Light and Computer Aids Smart card

Closure... The College-Industry Council on Material Handling Education (CICMHE) principles on MH (Askin & Standridge, pg. 296; Tompkins et. al., pg. 158) MHS-related information sources: Tompkins et. al., pgs 280-281 An interesting site: http://www.mhia.org/et/mhe_tax.htm