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Insiderís View of Revolutionary New Pallet Design Tool:PDS Tips and Insights from the NWPCA
PDS 5.0 Tips and Insights: PDS director John McLeod explains the developments and benefits of the latest PDS version, including specifying and drawing the entire unit load.
By Chaille Brindley
Date Posted: 8/1/2012
If you want to know what more than 30 yearsí worth of research and development in pallet design looks like, take a tour of the latest version of the Pallet Design Systemģ (PDS). Although PDS has been an industry institution for decades, Version 5.0 (V5.0) is truly revolutionary in its features and enhanced capabilities.
††††††††††††††† Developed and marketed by the National Wooden Pallet & Container Association (NWPCA), PDS has become the defacto standard worldwide for designing pallets and measuring pallet performance. And the latest version is the most important change to the software in its entire history.†
††††††††††††††† PDS Version 5.0 contains new structural analysis models that are based on state-of-the-art wood pallet design, all relevant historical data and the latest laboratory and field test data. Most importantly, the newest version now enables pallet manufacturers to specify and draw the entire ďunit loadĒ Ė consisting of the pallet, containers and load stabilizers. This allows users to determine how to change the deckboard design to provide the best coverage for various container sizes and configurations, visually inspect the interface between the bottom deck and the top of a unit load in a stacking pattern, and visualize the various stacking patterns of boxes and containers.
††††††††††††††† John McLeod, PDS director for the NWPCA, recently gave me a tour through the software and participated in an interview about the latest developments.† The following is a question and answer style article about V5.0.† Even if you are a PDS pro, you may want to read about some of the tips and insights that John McLeod covers in our discussion.
Pallet Enterprise: What has changed in terms of the structural analysis behind PDS?
McLeod:† We re-wrote all the structural analysis models in V5.0. They had been in various stages of sophistication. We first developed the stringer class models and hadnít modified them much since version 1.0. Those were somewhat antiquated. And then we developed the block class models a few years later. Computer technology had advanced to the point that we could do a three dimensional model. And we really had to because the block style pallets are so much more complicated than stringer designs. Then we had the panel deck analysis which came in the 1990s. And that was even more advanced. So in V5.0, now we are using similar techniques for analyzing all designs.†
††††††††††††††† V5.0 enables structural analysis of wood pallets with two-to-nine stringers, two-to-29 top and/or bottom deck boards, two-to-seven blocks along stringer boards and two-to-nine rows of stringer boards/blocks across the pallet width. Essentially, V5.0 enables pallet manufacturers to specify, draw and analyze performance of almost any wooden pallet design.
Pallet Enterprise: Explain how the new unit load specification features work. Why would this be of interest to pallet companies and pallet users?
McLeod: PDS users can now specify much more than just the pallet. They can specify a variety of loads and stabilizers. We will be adding more options in the future. But what we have right now are containerized loads that use boxes, pails, bags, drums or a bulk box or a bulk bag. You can specify any dimension box or container that you want. If you want to specify the corrugated board, you can do that, too. You can also specify the color of boxes and include graphics.
††††††††††††††† Based on the designed pallet footprint and the size of the box, the software calculates all the different ways that you can stack the boxes on the pallet. This can range from full coverage down to one box, and the space efficiency is shown. You then specify the number of layers of boxes. If possible based on the arrangement, you can specify interlocking stacking. It will tell you the total weight of the load and the total height of the load. You can also specify load stabilizers, such as straps, stretch wrap, shrink wrap, tie sheets, corners and edge protectors, etc.
††††††††††††††† Right now you are just specifying and drawing the unit load. The next step in the development of PDS is to analyze the entire unit load from a structural analysis and performance perspective. The top view shows if the corners of the boxes are supported by deck boards. This helps you identify how you can change the placement of deck boards or stacking patterns to ensure that boxes are properly supported. You look for places where compression stress suggests the boxes and products may be damaged.
††††††††††††††† You also have to look at the interface of the bottom deck and the top of the boxes because you are going to be stacking unit loads in many cases.†
Pallet Enterprise: What can the latest version do in terms of racking and stacking patterns and the interaction between unit loads placed on top of each other?
McLeod: V5.0 can analyze pallets stored in overhead racks with two-beam, three-beam or shelf support of the pallet. Performance of pallets in ASRS systems, which are sensitive to deflection, can be evaluated. Four-corner support and lifting and handling of pallets with forklift can be analyzed. Stacking multiple unit loads in the warehouse or during shipping can be evaluated.
††††††††††††††† In addition, V5.0 computes and displays all possible stacking patterns for a layer of containers on the pallet, and calculates the footprint efficiency for each possible configuration. Stacking multiple layers of containers is displayed, with either interlock or column stacking for boxes and bags, and the overall dimensions and weight of the unit load are calculated.
††††††††††††††† The interface of the top deck of the pallet and bottom layer of containers is displayed, and PDS users can arrange deck boards so they properly support and protect the containers. Similarly, the interface of the bottom deck of the pallet and top of the unit load is displayed, and users can arrange bottom deck boards so they align with container corners, edges and rims in order to maximize stability and prevent damage to the containers when stacking multiple unit loads in the warehouse or during shipping.
Pallet Enterprise: What is a lesser known feature of PDS that users have found very helpful?
McLeod: There is a whole lot that PDS can do that many customers may not know about. I guess thatís true for me with many software products. I use it for what I know and need to do and donít take the time to discover other functions. I am busy and so is everybody else.
††††††††††††††† One neat feature of PDS that everybody may not know about is the production order information screen. This was added a few versions ago. The production order information is intended for the crew that is going to produce the pallet - not the customer. It helps production employees build a pallet to the true customer specification. It contains any notes needed to highlight customer preferences and identifies the nail and lumber specifications to be used. PDS can show the details in fractions of an inch so that a worker can more easily understand the lumber dimensions.†
††††††††††††††† What is really useful for the production employees is that it has a production order cut list. This tells you how many pieces of each dimension are needed. And it has assembly setup data to help you know how to setup your jig.
††††††††††††††† PDS will export electronically to the Viking Turbo. And we are willing to export to other equipment, but that is the only machine where there is sufficient demand for this function at this time.† PDS exports a file that the Viking Turbo can read. Instead of you having to go to the Turbo to type in the location of the components, it will read the file automatically, which eliminates having to enter the data twice.
Pallet Enterprise: Why is visualizing the load on the pallet so helpful?
McLeod: Before this version, you couldnít see it. Now you can visualize what the load looks like on the pallet. So if you have a load with concentrated touch points, such as a piece of machinery with legs, you can easily analyze the load to identify any support concerns.†
Pallet Enterprise: What are some smaller changes in V5.0 now that we have talked about the data and unit load enhancements?
McLeod: Now we have added forklift supports. It is a complicated analysis. You can select from a list of common fork dimensions or you can specify the lengths of the fork tines and the spacing. If you specify a pallet design or fork geometry that is incompatible, you get a warning message which indicates your options to solve the conflict.
††††††††††††††† The latest version also includes a three beam support for racking situations. Also, we added a shelf support for loads in racks that have solid shelving underneath. In the past, we told PDS users to use the stacked load analysis. But when that pallet is 50 feet in the air sitting in a rack, even with shelving, the consequences of that pallet failing are different than if the pallet is sitting on the floor. So, we can impose a higher level of safety in the most recent version for shelf support versus the stacked analysis when supported by a floor.
Pallet Enterprise: What does PDS consider results in a pallet or unit load failure?
McLeod: PDS creates a structural analysis model for the pallet design, and then imposes the specified load on that model under all the specified support conditions. Itís all math. Then PDS calculates the stress on each component in the pallet. It determines which component has the highest stress compared to its strength. This is identified as the critical member which limits the safe maximum load.
Pallet Enterprise: What if a PDS user has a difficult time figuring out the changes to the latest version?
McLeod: Any time that a user has a question about something, they can go to the userís guide or click on the little question marks next to the item for more information. We also offer telephone technical support and training classes throughout the year. A list of the latest classes is available on our website. (Note: also see the attached sidebar for the scheduled classes this year)†
Pallet Enterprise: Is PDS good for doing just a quick pallet drawing without all the analysis?
McLeod: Yes!† PDS offers three pallet design options. The Pallet Drawings Only option allows users to quickly specify the pallet just enough to create fully-dimensioned drawings. The Pallet Specification and Drawings Only option additionally requires input of the specs for the lumber and fasteners used to construct the pallet. The Pallet Analysis option further requires specification of the load and support conditions for the pallet.
Pallet Design System© 5.0 Training Courses
August 9-10, 2012 in Denver, Colo.
September 20-21, 2012 in Philadelphia, Penn.