The introduction of the Pallet Design System computer software (PDS) in 1984 was heralded as the most significant management/sales tool ever available to the wooden pallet industry. Accolades about PDS were numerous. But as time went by, PDS began to lose its marketing impact on pallet users despite numerous upgrades to the program.
Adding 3-D graphics to the PDS program was batted around in PDS circles for several years, but no distinct graphic step had been taken due to the costs. When Groupo36, a young Italian software company, exhibited its graphics software at the FEFPEB (the European umbrella pallet association) meeting in 2004, the National Wooden Pallet & Container Association (NWPCA) leadership took notice. By February, 2005, at the NWPCA annual leadership conference in Tampa, discussion of adding graphics to PDS was in full swing.
Then this spring, the NWPCA hired John McLeod, who had written all of the PDS code, to oversee an aggressive rewrite of the program. John contacted the Software Technologies Laboratory at Virginia Tech and started to develop version 3.5 of PDS, the first version with enhanced graphics. Version 3.5 has been completed and shipped to customers, and version 4.0 is on the radar screen for completion at or shortly after the NWPCA annual leadership conference coming next February in Marco Island, Fla.
Training conferences on PDS have been held regularly over the last two decades, so I am not making any attempt to provide a detailed exposure to PDS. Instead, I will cover a brief overview of the value of PDS and what the program has provided, followed by specifics on some of the changes being offered through the new PDS 3.5 version and the soon to be available version 4.0.
In simple terms, PDS combines the input of the specifications of a wooden pallet with some general description of the type of product being moved and the overall nature of the material handling environment. PDS analyzes these inputs and provides an engineering analysis of the safe maximum load that the pallet can carry, along with its deflection at maximum load. Using PDS, different pallets can be compared to determine the best choice for a particular customer under a specific set of circumstances. Pallet designers use PDS as the major tool to play "what if" games by comparing one pallet alternative to another. PDS users should stay alert for announcements of training sessions that fit their needs and calendars.
PDS has been regularly improved over the years. Originally the program only analyzed designs for new stringer pallets. Since then, block pallets, panel-deck pallets, and remanufactured pallets have been added.
PDS 3.5
PDS 3.5, the newest version of PDS, contains all of the positive qualities for which PDS has been known, plus significantly enhanced graphics. There are some other graphics programs that will draw pallets; some of them draw boxes and crates too. But to our knowledge there is no other program that provides pallet performance diagnostics. In that sense PDS is unique because it analyzes a pallet for its strength, deflection properties, maximum weight loads, etc. Performance characteristics include pallets that are racked across stringers, racked across deck boards, stacked one unit load high, and stacked multiple unit loads high. A lateral collapse analysis helps determine a pallet’s resistance to collapsing from side stresses.
A software user can input any specified deflection limits for a pallet being racked across either stringers or deck boards, and PDS will determine maximum loads for these specified limits, as well as the safe maximum loads. In addition, PDS 3.5 will identify which design elements are critical for a user specified deflection limit, identifying such members as center stringers, bottom deck boards, or top deck boards as being the critical members.
The pallet durability analysis in PDS 3.5 includes a pallet service life analysis that simulates a series of forces and impacts applied to the pallet during each handling cycle. Results from this handling cycle simulation include the expected number of cycles to first repair of specific components, such as top and bottom lead boards and exterior stringers, and cycles to first replacement. It indicates which components are the ones that are most likely to limit a pallet’s service life.
A physical property analysis provides information about a pallet’s weight at time of manufacture when green versus different moisture content levels as the lumber dries. It also provides dimensional shrinkage for the different components when moisture content of green lumber drops to 19% and then 15%.
PDS 4.0
John anticipates that PDS 4.0 will be available early in 2006. Indications are that the NWPCA is pushing further PDS improvements fairly hard. John has written and developed PDS over the years at Virginia Tech. Now, he is supplementing his programming efforts with that of others at Virginia Tech. So, due to the number of programmers who can develop software advances and the qualities of their unique backgrounds, the potential exists for fast tracking some future PDS improvements.
PDS 4.0 will be a major upgrade, intended as the platform on which PDS is continually improved for the next five years. Eventually it will include specification and analysis of the entire unit load. PDS 4.0 will include all the features and capabilities in PDS 3.5 plus the improvements and additions in display 1.
Adding graphic capability to PDS has been at the heart of PDS discussions for over a year. One of the significant developments is that PDS graphics will be developed to draw pallets, containers, and crates that will not be limited solely to those it can analyze for its engineering performance. The NWPCA is on track to expand PDS and its features faster and further. Earlier versions of PDS had graphics limited to two dimensional drawings that were informative but not very dynamic. Improved graphics are appearing in versions 3.5 and 4.0, and continued graphic advances are likely to evolve from this time forward. See figure 1 for three dimensional drawings of both the top and bottom views in the new 3.5 version.
For more information on the new versions of PDS, contact the NWPCA at 703/519-6104. For PDS consultation or analyses, contact either the NWPCA at 703/519-6104 or Virginia Tech at 540/231-3043. People who have not leased PDS can get individual PDS analyses for a fee if they wish.
