Plastic E-Pallet Redesign

Metis Design Corporation has been involved with a variety of design projects with Envirokare Tech Inc., developing products that use fiber reinforced plastics and the TPF process. The original design contract between MDC and Envirokare was to redesign their flagship product, a general use plastic pallet called the E-Pallet. Plastic pallets are rapidly becoming more commonplace due to their robustness and cost savings, as compared to traditional wooden pallets. An initial design of the E-Pallet, developed by Envirokare, was tested by the Pallet and Container Research Laboratory of Virginia Polytechnic Institute and State University, located in Blacksburg, Virginia. The testing verified that their pallet could safely carry a 2,800 lb load both in rack-mounted and conveyor configurations and that the pallet was very damage resistant. It was also determined that in the process of attempting to confidently pass the testing procedures, their pallet had been significantly over designed. The pallet was extremely heavy due to excessive ribbing and therefore was costly to manufacture. Additionally, there were some cases where under high loading the legs of the pallet would crack. In light of this test data, Envirokare decided to pursue a redesigned E-Pallet, which would be lighter and more cost effective without sacrificing durability. With these goals, Metis Design was approached to employ their experience in reinforced plastic design and structural analysis.

MDC used a combination of 3-D solid modeling (SolidWorks) and Finite Element Analysis (FEA) software to redesign the pallet. Much of the pallet geometry was specified by the customer because of its future use in the shipping industry (double sided forklift entry and pallet truck use). To overcome these challenging constraints, MDC designed a new ribbing pattern that would give the pallet sufficient strength, without adding excessive weight. Reducing the material thickness so that there was more consistency with the rest of the pallet relieved stress concentrations at the base of the legs, which were believed to be the cause of the cracks seen during testing. The final design was 35% lighter than the original E-pallet design and significantly easier to manufacture. Eliminating excessive ribbing and implementing uniform wall thicknesses also reduced warpage and sinking, improving the overall aesthetics of the part. In addition to the two-piece pallet redesign, MDC also designed a single shot design that may be developed in the future for additional cost and weight savings. Envirokare's product page.

Return to Mechanical Design.