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Block Pallets in Our Future? Block Pallet Manufacturing Methods
Manufacturing Block Pallets: The interest in block pallets is growing. This article focuses on the options available in building block pallets as well as a historical look at the significance of block pallets from a worldwide perspective.
By Ed Brindley
Date Posted: 12/1/2008
The Block Pallet World
By now many readers are aware that COSTCO has said it prefers block pallets and is encouraging suppliers to ship on this kind of platform. Other major retailers have also made comments about preferring block pallets for shipping to stores. The National Wooden Pallet & Container Association (NWPCA) is working with leaders in the grocery industry to develop a block pallet alternative for white wood companies. The bottom line of these developments is that it appears block pallets are likely to become a more prominent part of the
Block pallets remain mostly a minor concern for most pallet companies. Thus, there is a need for some readers to become more knowledgeable about manufacturing block pallets. I will approach repairing block pallets in a future article.
While you might think making a block pallet is no big deal, there are a number of issues that could be crucial if you decide to take the plunge toward block pallets.
Block Pallet Background & History
First, block pallets occupy a prominent place in the materials handling world in many parts of the world. While
The pallet industry has grown internationally as more parts of the world have become industrialized. Outside of the
In addition to CHEP, EURO, and chemical pallets, other common block pallet markets include 44x56 glass pallets, can pallets, beer pallets, and paper pallets.
A growing portion of grocery manufactures in this country are leaning toward block pallets. The NWPCA is working with several trade associations, including Food Marketing Institute (FMI) and Grocery Manufacturers Association (GMA), to develop the Pallet Industry Management System (PIMS). Designed around a 48x40 block style pallet, PIMS would be an open pool similar to what the Europeans have with their EPAL Europallet pool. To my knowledge, at this point no decision has been made about the details of this new pallet’s specification. Preliminary pictures indicate it will be a perimeter base block pallet similar to the current CHEP design.
While it is true that true four-way entry has significant benefits for the pallet user, the biggest advantage to the new PIMS program may be the management changes associated with this new pallet system. Installing a system with better quality control and better management of the pallets would serve customers better.
Block Pallets versus Stringer Pallets
What will a shift toward more block pallets mean to the pallet industry? What is good for our customers may not necessarily be good for our industry as it is currently fashioned. It may benefit both if it is done properly, but it carries some risks as well.
Why would a professional pallet person be concerned about a new block pallet push? Let’s consider some of these issues.
First, a move toward block pallets would require more pallet companies to change and gear up to either manufacture or repair block pallets. This is not a minor change.
Second, companies might find themselves having to use more softwoods instead of hardwoods because most block pallets are made from softwoods. How much of this is due to necessity and the desire for lighter weight? How much is due to habit? I believe it is mostly due to historical developments. It is true that block pallets have their home in
When examining the impact that softwood block pallets will have on our industry, keep in mind that we have historically depended heavily on hardwood supplier sources. States across the middle part of the country from Pennsylvania southward through North Carolina and west through Missouri and Arkansas, known as the “pallet belt,” have supplied significant quantities of hardwoods to both the local pallet companies and those serving markets either north or south toward the border states. What will happen to the hardwood pallet manufacturing industry in those states if our industry switches more to softwoods? In addition to the impact on hardwood sawmills across the pallet belt, where will our industry get the softwood supplies that it will need to build significant quantities of block pallets? Will it come from the Southern Yellow Pine mills in the Southeast? Or will it come from northern SPF sources, mostly
The main difference between block pallets and stringer pallets is the way block pallets are constructed to allow full four-way entry. This important distinction provides the user benefits that are the very reason that many of them prefer block pallets. In order to get into stringer pallets from the sides, the most common practice is to notch the stringers to make room for fork tines to enter. A common form of block pallet uses three sets of three blocks with a stringer board laid across the blocks and nailed into them, sometimes called a dumbbell. The additional height of the blocks versus the height of stringer notches and the additional spacing between the blocks versus the width of a notch allow a much wider variety of fork truck and hand jack options.
It is important to mention that most pallet manufacturing capacity in
The nailing patterns and requirements of block pallets lend themselves best to using nailing systems that are designed to assemble block pallets. Domestically GBN manufactures machines that can build block pallets, with its systems ranging from a single nailing machine and jig to a high speed tandem automated system. Other high speed automated block pallet assembly lines are available from European machinery companies where block pallets are more common. The most prominent European supplier serving the
Block Pallet Manufacturing Options
Everybody in the pallet industry knows that block pallet manufacturing is more of a challenge than manufacturing stringer pallets. In addition to the inherent problems in block pallet construction, most pallet companies have limited experience with block pallets. Their pallet fabricating machinery is typically designed for manufacturing stringer pallets, and most of it can not be easily modified to fit block pallet construction. Thus, while the pallet industry may be willing to tackle a block pallet challenge, there is some doubt that the physical capabilities of our plants are up to any short term adjustments toward block pallet fabricating.
The kind of block pallet program being proposed for the grocery industry calls for a high quality pallet. In particular, a high quality perimeter based block pallet is a challenge to build in significant quantities without investing in a high cost automated nailing system. Because of the challenging nail patterns involved in block pallets, it is difficult to accomplish this with hand nailers.
The nailing patterns can be difficult, and the nail sizes required can vary considerably. It is difficult to clinch nails using hand tools because it is difficult to provide the pressure required by hand. I am not saying that you cannot make block pallets on hand tables using hand tools; obviously you can. But it is questionable whether or not you can fabricate quality pallets in the quantity that a new block pallet grocery program will require.
When talking about block pallet assembly, one has to tackle the basic concept that differentiates block pallets from stringer pallets. Block pallets use blocks, usually nine of them, with stringer boards on top of them (typically three stringer boards). Thus, a stringer is typically replaced by three blocks and a stringer board, a unit called a dumbbell.
The common Europallet or unidirectional block pallet typically has three bottom deck boards, each nailed to the bottoms of three blocks to form a dumbbell. The top deck boards are nailed to the top stringer boards to form a mat, which is then nailed into the blocks of the three dumbbells. Fork trucks and hand jacks can enter this style of pallet from all four sides, either from the ends between the dumbbells or from the sides between the blocks and the stringer deck boards of the dumbbells.
There are other styles of block pallet bottoms; certainly one of the most common is a perimeter based picture frame style. This kind of bottom looks like a picture frame with five bottom deck boards. Each bottom deck board is typically nailed to three blocks. Some of the top deck boards are nailed using longer nails through the stringer boards into the blocks. In the top joints that are not above a block, the deck boards are nailed into the stringer boards. These joints usually use either a clinch style nail that turns upward into the stringer boards or a short ring shank nail that has more limited holding power.
The strongest joints use clinch nails. Shorter unclinched nails are more likely to come out easily. Initially, CHEP pallets used short nails in these joints but has changed its specification to use clinched nails. PECO pallets use short nails in these non-block joints.
Most block pallets use two or more nail sizes and more complicated nailing patterns than stringer pallets. And the clinching concept requires special nailing capabilities. It takes longer to build a block pallet, which causes it to be more labor intensive and more difficult to manufacture.
One of the most common methods to build a block pallet uses multiple stages. The top deck boards and stringer boards are assembled into a mat which is then nailed into the blocks with long nails. A common nailing option is to assemble the mats and dumbbell bottoms (Euro-style pallets) in two different steps. Then nail the top mat onto the dumbbells using long nails.
Stringer pallets can be rapidly built on tandem nailing systems where two nailers with a turner between them perform the needed nailing functions. Pallets can then be stacked for efficient handling on a pallet stacker. Block pallets can be fabricated on tandem nailing systems as well, but the nailing machines are a more complicated, and the steps present a greater challenge. Thus, a tandem block pallet nailing system is more expensive.
The only high speed tandem block pallet nailing system available today from a
These high speed systems are capable of manufacturing both large quantities of pallets and high quality pallets. They can include automated block cutting and feeding machines. Some are engineered to use robotics to position the deck boards. Most of the perimeter based block pallets in rental systems in
In addition to high speed tandem block pallet assembly systems, block pallets can be made in stages on other bulk-nail nailing machines. In addition to GBN machines that can be manufactured or retrofitted to build stages of block pallets, older styles of
Many old 60” Doig nailers, 72” Morgan nailers, and 60” FMC nailers are around the industry. Some are still nailing pallets, and many are moth balled in bone yards. Nailer frames that are 60” wide or wider can be used to simultaneously nail three dumbbells for a EURO-style pallet on one side and assemble the top mat on the other side. Because there are hundreds of these older nailers around the country, the potential for machine nailing block pallets without having to buy expensive high speed systems is there. Because only a few companies are experienced in rebuilding and retrofitting these older machines, our nailing machinery companies might not be able to respond as rapidly as we would like for them to if a surge in demand materializes.
A pallet manufacturer can use one beam style nailer to build mats, a second to build dumbbells, and then nail the two together.
Using older nailing machines, a pallet company can use a jig to nail bottom deck boards to the blocks. Six or more dumbbells can be assembled on each pass through the nailing machine. The dumbbells are placed on a machine, the stringer boards laid on top of the blocks, and deck boards placed on top of the stringer boards. The entire unit then passes through the machine for final assembly.
A few beam nailing machines are available with either fixed or disappearing clincher blocks or plates. This feature allows the machines to perform the desired nail clinching function. Clinching options include fixed plates with off-center clinch nails. To clinch successfully a machine uses hardened steel plates; otherwise they will not stand up to the abuse that clinching will give. Power clinching, such as that used in cable reels, uses a standard common nail. The under plate moves during the nailing stroke. The point follows around and makes a fish hook. The clinching concept is not well known in the North American pallet market because of the dominance of stringer pallets.
Clinching with hand tools can be a challenge, and finding the correct collated clinch nails is reportedly not always easy. A new block pallet manufacturing push in the market, such as the new PIMS program proposes, is likely to require machine manufacturing to meet high quality and consistency standards.
Block pallet mats can be manufactured on stitching equipment that makes staples from continuous coils of wire. Machines such as those manufactured by Stapling Machine Company (SMC) are designed to manufacture block mats and other styles of wooden packaging that use staples.
Another kind of machine that a pallet manufacturer may need to efficiently build block pallets is some kind of a block cutter. On the top end of the spectrum, automated block cutting and feeding systems are available from all manufacturers that build high speed tandem nailing systems. Less expensive machines include the block cutting unit available from Samuel Kent Baker and chop saws or pop saws that can be used for a variety of crosscutting requirements.
While a new block pallet market might desire machine made block pallets, as previously mentioned, you can build them using hand tools and jigs. Clarence Leising, a well known expert in pallet recycling techniques and author of the book Pallet Head, has a short chapter in his book entitled “Block Pallets and Block Bins”.
Clarence indicated that for ten years the
Many readers are probably familiar with the composite blocks that are often used in block pallet construction. Composite blocks are manufactured from wood fiber mixed with a binder under heat and pressure. The first time I saw a composite block I questioned the concept. I could not see how they could hold a nail very well and was surprised to find out that they are a common practice in European block pallets. They have proven to hold nails pretty well, particularly the annular ring shank nails that are so common in softwood block pallet construction.
Sandy Campbell, a well known representative of GBN nailing systems, has lived his whole life around the pallet industry, in particular nailing machines.
What does the future hold? If block pallets experience a solid growth in