Economics of grading and sorting pallet parts

Before trying to develop an automated inspection system for pallet part grading we analyzed the economics of such a system. Our results suggest that higher quality pallets produced by grading and sorting pallet parts would be attractive to both manufacturers and their customers, who would have to pay increased prices for higher quality pallets. Reductions in costper-trip for the pallet purchaser should permit pallet manufacturers to recoup investments for pallet part sorting. The utility of higher quality pallets should be economically attractive to pallet purchasers even for pallets with much higher prices than those currently used. Wood pallets comprise the largest single use of sawn hardwoods in this country. Unfortunately, millions of pallets are discarded annually due to 1) pallet damage; 2) one-way use; 3) delivery to a location where they are not re-used; and 4) improper pallet design for a specific use. One-way-use pallets constructed with little concern for durability quickly find their way to landfills. When not disposed of in this way, they are often ground or chipped into fiber for fuel, animal bedding, or other uses (e.g., mulch), or are disassembled and re-used. High quality wood pallets would be more durable and more expensive, but they would promote longevity and re-use. High quality and value would make repair and re-use good financial decisions. Aside from availability, pallet durability and re-usability are the two attributes most important to pallet buyers. Pallet manufacturers and their customers, however, must National Wooden Pallet and Container Association. 1993. Pallet User Survey. NWPCA, Arlington, Va. National Wooden Pallet and Container Association. 1993. Pallet Design System. NWPCA, Arlington, Va. be convinced of the economic viability of investment in high quality pallets. The National Wooden Pallet and Container Association (NWPCA), the USDA Forest Service, and Virginia Tech have developed a computerized procedure for designing pallets, the Pallet Design System (PDS). PDS permits the analysis of different pallet designs based on lumber species and grade, part dimensions, pallet geometry, fastening system, materials handling environment, and pallet price. Just by increasing pallet part thickness and changing fasteners, it is possible to more than double a pallet’s durability. A survey of pallet users has indicated their willingness to buy higher quality, more durable pallets. 1 High quality pallets require high quality parts. Standards for various grades of pallet stringers and deckboards, set forth by the NWPCA, allow for the potential to separate pallet parts according to grade prior to construction. However, there are three major problems to pallet part grading: 1) training and maintaining pallet part graders can be expensive; 2) the characterization of some degrading defects (e.g., slope of grain and knot cross section) can be difficult; and 3) the rate at which parts move through a pallet plant may preclude accurate visual grading. To address these problems, we are investigating the use of an automated inspection system to grade and sort pallet parts. An automated inspection system would consist of a scanning system capable of detecting defects in The authors are, respectively, Research Forest Products Technologist, USDA Forest Serv., Southeastern Forest Expt. Sta., Brooks Forest Products Center, Virginia Tech, Blacksburg, VA 24061-0503; Research Associate, Dept. of Wood Sci. and Forest Prod, Virginia Tech; and Project Leader, USDA Forest Serv., Southeastern Forest Expt. Sta. This paper was received for publication in May 1993. © Forest Products Society 1993. Forest Prod. J. 43(11/12):19-23. FOREST PRODUCTS JOURNAL Vol. 43, No. 11/ 12 19 TABLE 1. — Abbreviated list of grading criteria employed for stringers from PEP Study Report. a Defect Description 2&BTR 3 4