Tuesday, February 10, 2009
By Dr. Michael Ogle
Vice President, Educational & Technical Services
Material Handling Industry of America
The roughly five-hundred million pallets produced this year and two billion in circulation in the U.S. make a strong case for great impact on the supply chain, but are pallets a technology? Certainly doesn’t seem so when you look at one and don’t see any moving parts or electronics. However, the many moving parts and electronics in today’s automated systems see a lot of pallets flow through them each year.
What do you think of when you hear the word pallet? I’ll wager that the vast majority of the people think of the basic wooden stringer pallet design, if there was a picture in their head at all. That’s not unusual given the huge volume of them historically and in the current market. However, there is a great variety of pallet styles and sizes, particularly when you include all the materials (such as wood/paper, plastic and metal), sizes, and structural configurations.
Pallets often tend to be taken for granted like electricity and plumbing. If selected and applied correctly, they should fade into the background of a smoothly running material handling system, but when you notice them, it is likely due to a problem. For automated systems, that problem could result in a jammed system, reducing productivity and return on investment.
The Pallet Is Connected To The…
The pallet interfaces with many other products and technologies on its journeys through the supply chain. Looking at just a pallet load of goods itself as a unit (often called a unit-load in practice), we see that it is typically carrying multiple corrugated boxes that contain both protective packaging materials and the items that are supposed to make their way safely through the supply chain. Hopefully those boxes were sized and stacked so they don’t overhang the edge of the pallet or leave too much wasted space from the edge. The unit-load may also be wrapped, strapped, or otherwise secured to keep items together. Labels or RFID tags may be attached to keep track of it. The pallet likely has slots or cut out areas so an industrial truck can pick it up from all four sides. Of course, that pallet then becomes part of a larger shipment that has to go into a freight container or a truck for delivery.
All those connections to other components make the pallet a critical part of the supply chain. But too many companies simply think of lowest cost in volume when specifying pallets, particularly in automated systems. Balancing demands upon the pallet is part of the art in systems thinking.
If a pallet is going to flow through an automated system, it needs to be compatible with the demands of that system. The total lifecycle should consider all cost factors related to purchase (includes initial cost, disposal, reusability costs), transportation and warehousing. An extra dollar or two for pallet quality up front not only helps the unit-load arrive safely, it may result in many more trips for that pallet, lowering the all-important cost per trip measure.
There Ought To Be Standards For These Things
Ah, but there are. Material Handling Industry of America (MHIA) administers the most comprehensive industry standard on pallets, MH1-2005 Pallets, Slip Sheets, and Other Bases for Unit Loads. The 207 page standard defines terminology and nomenclature associated with pallets, provides a series of recommended pallet dimensions and sizes, describes procedures for pallet sampling, inspection and testing, plus it applies to pallets irrespective of components and materials used in their fabrication.
For pallet use in automated systems, the standard provides valuable specifications for construction of pallets. It covers pallet size and shape variation (length, width, height), squareness, flatness of decks (when supporting no load), minimum static coefficient of surface friction, component placement variation, maximum deflection of the pallet under load, minimum clearance between pallet under load and handling equipment, and maximum deflection of pallet components under load.
Finally, more work is currently underway in the MHIA administered and MH1 committee on “Pallets, Slip Sheets and Other Bases for Unit-Loads”, accredited by the American National Standards Institute (ANSI). The committee is developing three more parts of the standard to expand detailed material coverage on plastic pallets, single-use/reusable paper-based pallets, and metal pallets. It is hoped that these new sections to the standard will have just as much influence on international pallet standards as the original.
The MH1 standard is available in the MHIA bookstore. For more information, contact Mike Ogle at 800-345-1815/704-676-1190.
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