Slip sheet

Not to be confused with slip sheets used in printing to divide between copies or avert set-off.

A load stretch wrapped with slip sheet on Rotary Arm Stretch Wrapper. Slip sheets in foreground.

Slip sheets are thin pallet-sized sheets made of plastic, heavy laminated kraft paperboard, or corrugated fiberboard used in commercial shipping. Often, these replace the use of traditional wooden pallets. The unit load is usually stretch wrapped or shrink wrapped for stability.

Description

The slip sheet is used as a pallet support device in vehicle delivery and transportation of products. When slip sheets are supported by a pallet board, flat load carrying surface, or a cart or fork lift truck, the structural strength of the slip sheet supports the product load's weight. With the slip sheet supported by one of these transportation devices the unit load can easily be transported both internally within a facility and externally between two facility locations.

Slip sheet types

There are several types of slip sheets that can be used for the transportation of a unit load depending upon the desired use of the sheet. The slip sheet is shaped and dimensioned to the size of the product or unit load. The type of slip sheet varies depending on both the number of lip extensions and the material from which it is manufactured.

The variation used would depend on the loading patterns, unit load parameters, and desired maneuverability of the slip sheet/unit load. Normally, the thickness of the slip sheet is less than 0.5 inches.

The slip sheet has a four to six inch lip (tab) that extends beyond one or more of the sides of the slip sheet. The lip extensions permit a push-pull device to lift the slip sheet unit load.

Single lip

The first type of slip sheet is the single lip (tab) slip sheet.

With a single lip, the lip faces the narrow part of the rectangular shaped unit load and the delivery truck door. This slip sheet variation maximizes the delivery truck’s space utilization and loading and unloading process productivity. Also, with a single lip, the travel path clearance is minimized as the lip faces the unit load carrier.^[1]

Multi-lip

The second type of slip sheet is the multi-lip slip sheet. This type of slip sheet is generally used on a container placed onto a railroad car or an ocean delivery vehicle due to the necessary loading/unloading patterns. This allows a loading device to load the slip sheet unit load from one side and an unloading device to unload the load from another side depending on the number and pattern of the remaining lips.

Lip handling options

During the transportation of a slip sheet, there are several options for handling the slip sheet’s lip.

Leave the lip extended allowing for additional clearance for the travel path.
Tape the lip against the unit load if additional push-pull activities are required.
Cut the lip from the slip sheet if no additional push-pull activities are required.

Slip sheet materials

Corrugated

The corrugated fiberboard consists of two kraft liner board outer surfaces with a corrugated interior that is bonded together with adhesive or glue. This bonded material provides the necessary strength for the push-pull device to clamp the slip sheet once or twice. There are several disadvantages associated with this type of slip sheet material including that it is not very durable, moisture resistant, resistant to high humidity or usable in cold storage areas. The advantages associated with this material are low cost, one-way use, and its ability to be moved by a conveyor or lift truck with a slip sheet device.

Fiberboard or solid kraftboard

The fiberboard (thick paperboard) slip sheet consists of several layers of solid kraft paperboard sheets laminated together. The bonding of layers of several flat solid kraftboard sheets increases the slip sheet’s non-tear strength. This, in return, allows the slip sheet to be used several times and in different temperatures. In addition, some fiberboard slip sheets are protected by a plastic coating to improve its use in humid environments. The disadvantages to this type of slip sheet are that it has a medium cost and is not very durable. The advantages with this material are its multiple uses, ability to withstand humid and cold environments, and ability to be handled by conveyors, AGV, or other power unit load transportation devices.

Plastic

The plastic slip sheet is made from recycled high-density polyethylene or polypropylene materials. This type of material allows for greater non-tear strength and an increased number of uses in cold and humid environments. The only disadvantage to the plastic slip sheet is the high cost. Yet, its advantages include longer sheet life, durable lips, ability to be stored in cold or humid environments, and that it can be handled by a roller conveyor, slip sheet lift truck, or powered unit load transportation devices.

Slip sheet vs. pallet

When considering the use of a slip sheet vs. a pallet, there are several advantages and disadvantages associated with both.

Slip sheet advantages

Using slip sheets instead of wooden pallets allows for 0–30% more products in material handling containers.
Significant reduction in material handling costs, especially on air shipments.
Weighs 1/30 as much as wooden pallets, reducing shipping costs.
Eliminates the need for pallet exchange.
Reusable and reliable.
Most are recyclable.
Is cost-effective.
Unlike wooden pallets slip sheets are not subject to phytosanitary restrictions.

Slip sheet disadvantages

Pallets provide a greater clearance between the floor and the unit load, an advantage when loading extra cargo into a container, but they take up more space.
Slip sheet usage requires special, relatively low-cost attachments on transportation devices such as a lift truck.
When used alone, pallets provide more structural support than slip sheets.
Pallets are easily compatible with cranes.
The floor clearance provided by a pallet can prevent the load from being damaged by wet floors.
Dragging a slip sheet load across a rough or bumpy floor can damage the load.
Lift truck attachment reduces load capacity, except when 'Roller Forks' are used.
Increases fork lift pick up and set down times by up to 60%, when 'Roller Forks' are used.

References

↑ North Carolina State University http://www.ise.ncsu.edu/kay/mhetax/UnitEq/Slipshet/index.htm

External links

Slip sheet patent and method of use

Packaging

General topics	Active packaging Child-resistant packaging Disposable food packaging Food packaging Luxury packaging Modified atmosphere/modified humidity packaging Package pilferage Package testing Packaging engineering Pharmaceutical packaging Reusable packaging Shelf life Sustainable packaging Tamper-evident Tamper resistance Wrap rage

Containers	Aerosol Container Aluminium bottle Aluminum can Ampoule Antistatic bag Bag-in-box Bags and flexible containers Barrel Beer bottle Biodegradable bag Blister pack Boil-in-Bag Bottle Box Bulk box Carboy Carton Chub Clamshell Corrugated box design Crate Disposable cup Drum Envelope Flexible intermediate bulk container Foam food container Folding carton Growler Insulated shipping container Intermediate bulk container Jar Jerrycan Jug Juicebox Keg Multi-pack Oyster pail Packet (container) Padded mailer Pail Paper bag Paper sack Plastic bag Plastic bottle Popcorn bag Retort pouch Sachet Security bag Self-heating can Self-heating food packaging Shaker-style pantry box Shipping container Skin pack Spray bottle Tin can Tube Unit load Vial Wooden box

Materials and components	Adhesive Aluminium foil Bioplastic Biodegradable plastic BoPET Bubble wrap Bung Cellophane Closure Coated paper Coating Corrugated fiberboard Corrugated plastic Cushioning Desiccant Double seam Foam peanut Glass Hot-melt adhesive Kraft paper Label Linear low-density polyethylene Liquid packaging board Low-density polyethylene Metallised film Modified atmosphere Molded pulp Nonwoven fabric Overwrap Oxygen scavenger Packaging gas Pallet Paper Paper pallet Paperboard Plastic film Plastic pallet Plastic wrap Polyester Polyethylene Polypropylene Pressure-sensitive tape Screw cap Screw cap (wine) Security printing Security seal Shock detector Shock and vibration data logger Shrink wrap Slip sheet Staple (fastener) Strapping Stretch wrap Susceptor Tear tape Temperature data logger Time temperature indicator Tinplate Velostat

Processes	Aseptic processing Authentication Automatic identification and data capture Blow fill seal Blow molding Calendering Canning Coating Containerization Curtain Coating Die cutting Die forming (plastics) Electronic article surveillance Extrusion Extrusion coating Glass production Graphic design HACCP Hermetic seal Induction sealing Injection molding Laminating Laser cutting Molding Papermaking Plastic welding Plastics extrusion Printing Quality assurance Radio-frequency identification Roll slitting Shearing (manufacturing) Thermoforming Track and trace Vacuum forming Ultrasonic welding Vacuum packaging Verification and validation

Machinery	Barcode printer Barcode reader Bottling line Calender Can seamer Cartoning machine Case sealer Check weigher Conveyor system Extended core stretch wrapper Filler Heat gun Heat sealer Industrial robot Injection molding machine Label printer applicator Lineshaft roller conveyor Logistics automation Material handling equipment Mechanical brake stretch wrapper Multihead weigher Orbital stretch wrapping Palletizer Rotary wheel blow molding systems Shrink tunnel Staple gun Tape dispenser Turntable stretch wrapper Vertical form fill sealing machine

Environment, post-use	Biodegradation Environmental engineering Glass recycling Industrial ecology Life-cycle assessment Litter Paper recycling Plastic recycling Recycling Reusable packaging Reverse logistics Source reduction Sustainable packaging Waste management

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