Material Handling Equipment

Thursday, January 10, 2008

Storage Equipment

• Block stacking (no equipment)
• Pallet Rack - Selective Pallet Rack, Drive-through rack, Drive-in rack, Push-back rack, Cantilever rack, etc.
• Stacking frame
• Shelves/bins/drawers
• Storage carousel
• Automatic storage/retrieval systems (AS/RS)
• Split case order picking system
• Mezzanine

Block Stacking

Block stacking is a palletized storage that does not use any storage equipment. Loaded pallets are placed directly on the floor and built up in stacks on top of one another to a maximum stable height. Warehouse safety is one of the primary concerns in warehousing. Therefore, it is recommended to have a maximum stable height of stacks (e.g. usually not more than six pallets). This aims to prevent accidents of toppling pallets.

Below is a video of which you could easily see how dangerous it is if accidents were to happen.

Ideally, any one row of pallets should contain pallets of the same products to avoid double handling and to simplify records of stock locations (where possible). When setting out the simple block stacking, clearances should be allowed for the movement of forklifts. It is recommended to have lines painted on the floor to help maintain the layout disciple.

Free access to retrieval of these pallets is limited only to pallets on top/ front of each row, or at the sides. Thus difficulties may be encountered in practicing First- In- First- Out (FIFO). This is especially the case for pallets which are situated in the ‘middle’ or ‘bottom’ of the blocks.Block stacking is said to be more suitable for stored products which have only few product lines, each with high inventory level to ensure FIFO movement of inventory. Hence it is a good practice to empty a row completely before replenishing any more products into that row.

With no storage equipments required, it provides flexibility for the warheouse to change the layout of blocks (when necessary). Below is a pictures are taken from a local bearing company, to illustrate bulk stacking in a warehouse. The logo has been blanked out to protect the confidentiality of the company.

Advantages of block stacking :

• lower capital cost
• no storage equipment needed
• good utilization of area/space in warehouse
• easy control
• suitable for throughputs
  

Disadvantages of block stacking :

• increase in material handling costs as FIFO is practised in warehouses and additional costs are incurred
• limits on stack heights which can restrict the use of building height
• honeycombing which reduces storage capacity
• no strict FIFO
• free access is only to pallets at the top of each row
• risk of fire as pallets are located very close to each other

Pallet Rack

A pallet rack, also referred to as “pallet racking,” is for stocking inventory that sits on pallets (or “skids”) that are stored in horizontal rows with multiple levels; pallet racks allow warehouse inventory to be stored more efficiently (called maximum storage density). The pallet racks link together to create a pallet rack system. Forklift trucks are usually required to place the loaded pallets onto the racks for storage because of their size and weight. Pallet racks are essential and ubiquitous to modern warehouses, retail centers, and other facilities.

Selective Pallet Rack

Selective pallet rack systems are the most commonly used rack system because they are inexpensive and quick and easy to assemble. Selective pallet racks typically come in two configurations: a teardrop, or clip-in configuration, and a structural bolt-together configuration. The nickname “teardrop” comes from the fact that the holes on the column of the upright are shaped like a teardrop. Pallets then rest on the horizontal beams that are held in place by mounting clips.

Because the clips on teardrop configurations can be quickly moved, the shelves can be easily adjusted to different heights to accommodate various load sizes. This is convenient for a warehouse that needs to store a wide variety of product sizes. Another advantage of selective pallet rack systems is the easy accessibility they provide to all products at all times. Such accessibility is important if the inventory is rapidly depleted and restocked (called quick turnover). A selective pallet rack system is commonly used in a “big-box” distribution application, as well as in retail store inventory rooms, cold storage applications, wholesale stores, etc.

Drive-In & Drive Through Rack

Drive-in and Drive-through (sometimes spelled Drive-thru) are storage rack configurations that allow the forklift to drive directly into the lane of stacked rows (called a bay). The difference between a drive-in and a drive-thru pallet rack system is simply whether the bays have an entry at only one end, or at both ends. Drive-in rack systems use a common entry and exit, while drive-thru systems have entry points at either end of the bay. Because a drive-in racking system has only one entrance, it uses what is called a “Last In, First Out” (LIFO) storage method. With only one entrance, the last pallet put into a row is necessarily the first one to be taken out. A drive-thru storage system, with two different entry points, can also use a “First-In, First-Out” (FIFO) storage method. With a FIFO system, pallets are loaded in one end and are pushed back to the other end, where they are then at the front of the row on the opposite side. The first pallet put into such a row is the first one taken out at the other end. This system is advantageous for material with an expiration date or wherever shelf life is a major concern.

Advantages of Drive-In / Drive-Through rack Systems:

• Eliminate conventional traffic aisles
• High density storage
• Floor -to-ceiling palletized storage
• Lower costs
• Greater Throughput
• FIFO & LIFO inventory management

Push-Back Rack

Push-back pallet rack systems are designed around the principle of organizing space by depth rather than width. This depth arrangement greatly reduces aisle space and increases storage density. In this configuration, each row is multiple pallets deep, and often has wheeled carts that fit onto rails to take advantage of gravity, saving enormous amounts of energy for moving heavy pallets. When a forklift sets the pallet onto the cart, it drives forward and causes the pallet to bump the next pallet, causing the entire row of pallets to roll backwards. When removing a pallet from the front position the remaining pallets immediately stage themselves forward so that the next available pallet can be accessed.

Here is a video to give you a better understanding of push-back racks.

Pushback rack increases product storage by 75% verses a selective rack system. Pushback rack system provides high density pallet storage, safer operation, less rack damage, more throughput, and higher productivity. Configurations for Pushback systems range from 2 to 6 pallet positions deep and up to 4 or more levels high. Pushback rack can greatly increase the number or pallet positions in an existing warehouse.

Cantilever Rack

Cantilever Racks allow full selectivity. They can hold long and irregular loads & standard or specialized handling equipment. With how its structured, it enables floor space savings.

Labels: Samantha, Storage Equipment

by SMS at 7:13 AM |