Unit Load Formation Equipment

Unit Load Formation Equipment

Unit load formation equipment used to restrict materials so that they maintain their integrity when handling a single load during transport and storage.

Advantages of unit loads:

• More items can be handled at the same time, thereby reducing the number of trips required and, potentially, reducing handling costs, loading and unloading times, and product damage.
• Enables the use of standardized material handling equipment.

Disadvantages of unit loads:

• Time spent forming and breaking down the unit load.
• Cost of containers/pallets and other load restraining materials used in the unit load
• Empty containers/pallets may need to be returned to their point of origin.

The information below demonstrate the major type of unit load formation equipment used.

1. Pallets

Information:

• Platform with enough clearance beneath its top surface (or face) to enable the insertion of forks for subsequent lifting purposes.
• Materials: Wood (most common), paper, plastic, rubber, and metal.
• Size of pallet is specified by its depth (i.e., length of its stringers or stringer boards) and its width (i.e., length its deckboards)—pallet height (typically 5 in.) is usually not specified; orientation of stringers relative to deckboards of pallet is specified by always listing its depth first and width last: Depth (stringer length) x Width (deckboard length).

2. Totes Pans

Information:

• Reusable container used to unitize and protect loose discrete items.
• Used for in-process handling Returnable totes provide alternative.

3. Intermodal Containers

Information:

• Reusable container used to unitize and protect loose discrete items.
• Enables a load to be handled as a single unit when it is transferred between road, rail, and sea modes of transport; e.g., the container can be unloaded from a cargo ship and loaded onto a truck as a single unit.
• Not common to use intermodal containers for airfreight transport because of aircraft shape and weight restrictions.
• Dimensions of intermodal containers are:20 or 40 ft. in length; 8 ft. in width; and 8, 8.5, or 9.5 ft. in height; less 8 in. of length, 5 in. of width, and 9.5 in. of height to determine the inside dimensions.

4. Shrink-Wrap/Stretch-Wrap

Information:

• Used for load stabilization.
• A film or bag is placed over the load and then heat is applied to shrink the film or bag.
• Allows irregular loads to be stabilized; manual or automatic.
• Most shrink-wrap applications are being replaced by stretch-wrapping.

In stretch-wrapping, a film is wound around the load while the film is stretched

• Allows irregular loads to be stabilized
• Manual or automatic
• Lower material, labor, and energy costs.

5. Palletizers

Informations:

Manual Palletizing

• Operators arrange items into the desired pattern used to form the unit load.
• Lift and turn tables are often used.
• Semi-mechanized palletizers use operators to arrange items into the desired pattern for each layer of the unit load.
• Powered device is used to transfer layers onto a pallet and then lower the load for the next layer.

Robotic Pick & Place Palletizers

• Fully automated device to build unit loads.
• Used when flexibility is required.
• Greatest limitation is capacity, typically 6 cycles per minute.
• Capacity is determined by the number of items handled with each pick operation.
• Operators arrange items into the desired pattern for each layer of the unit load
• Powered device is used to transfer layers onto a pallet and then lower the load for the next layer.

Conventional Stripper Plate Palletizers

• Fully automated device to build unit loads.
• Used when high throughput of identical loads is required.
• Capacity is typically greater (30–180 items per minute) than pick and place because an entire layer is placed on the load at one time.
• Not as flexible as pick and place
• Preformed layer of items (cases) are indexed onto the stripper plate (or apron)
• when properly positioned over the pallet, the apron is pulled out from underneath the layer to deposit the layer onto the pallet.
• "In-line" pattern formation (top picture)—flexible patterns are not possible.
• Ideal for high speed operation (up to 180 items per minute).
• Takes up more room (larger machine) than right angle.
• "Right angle" pattern formation (bottom picture)—very flexible patterns are possible
• Can handle a wide variety of case sizes and types
• Limited capacity (up to 80 items per minute)
• Compact design

For more information of Conventional Stripper Plate Palletizers, please visit the following website; http://www.pmtdirect.com/website/article.asp?id=1806.

Source:

http://en.wikipedia.org/wiki/Pallet
http://www.ise.ncsu.edu/kay/mhetax/UnitEq/index.htm
http://www.spectrasystems.co.uk/tote_pans.htm
http://www.kempner.co.uk/shrink-wrap-machines.aspx
http://www.stretchwrapsupply.com/stretch-wrap-machines-c-31.html
http://www.polypack.com/robotics.asp