There are many types of structural composite lumber (SCLs) commercially available now, and some new SCLs may come on stream in the near future. The SCLs that have prevailed in North America can be exemplified by glue-laminated timber (glulam), laminated veneer lumber (LVL), parallel strand lumber (PSL), and oriented strand lumber (OSL) or laminated strand lumber (LSL). Of these, glulam, LVL, and PSL are in mature stages, while OSL and LSL are still in their infant stages. The growing market potential of LSL is high because the LSL manufacturing technology can be further improved, particularly as its strand orientator (aka orienter) is substantially improved. Consequently, the production cost of LSL can be reduced and product properties can be enhanced. In general, different types of SCLs can be engineered to meet structural performance. The manufacture of SCL relies heavily on experience rather than the laws of science. Unfortunately, some experiences are biased because they are drawn from the manipulation of one or two variables without consideration of possible interactions with other factors. As a result, many SCL manufacturers have experienced start-up and growing pains in trying to engineer and produce low-cost products for specific applications while maximizing their profit. Nevertheless, the SCL industry has cumulatively amassed a lot of experiences and knowledge about manufacturing quality SCL. These experiences and knowledge are transferable, and any new SCL manufacturers can learn from these experiences and knowledge so that they need not make similar mistakes and go through similar start-up and growing pains as established manufacturers have already experienced. Nearly any new mill will have the same, or similar, equipment and processes as are used in existing mills manufacturing the same type of SCL. New manufacturers often learn from the experiences of the existing mills, both good and bad. However, it is essential to avoid experiencing the same problems encountered by the established mills. Otherwise, new SCL mills will fail to have a competitive edge over existing mills. One of my objectives in writing this book is to provide comprehensive information on the basics of SCL manufacturing. Another objective is to share my knowledge about SCL, experiences in research and development of SCLs, and practical experiences in the field. Hopefully, this book will help new manufacturers not make the same mistakes as established manufacturers, as well as assist established manufacturers with getting rid of bad practices. Although most of the basic information and knowledge of manufacturing different SCLs in this book can be found in existing published reports and books, this is probably the first book focused on SCL that covers the gamut of SCL manufacturing issues, including raw materials, equipment, processes, manufacturing parameters, challenges, and solutions for various kinds of SCL manufacturers. I have also attempted to highlight the important avenues necessary to make quality products at minimal production costs, and given my own thoughts of further improvement in product quality, processes and equipment.
Dr. Wu-Hsiung Ernest Hsu (aka Ernie Hsu) has 37 years of experience in research and development, mill practice, and consulting and advising for major wood composites companies. He specializes in process and product improvements, production cost reduction, process equipment improvement, development of various dual resin systems, strand orientators, and high performance composite lumber from relatively short strands. Ernie is a fellow of the International Academy of Wood Science (IAWS), holds his Ph.D. degree from the Department of Materials Science and Engineering, Washington State University, and has over 15 original process, equipment, and product patents related to wood composites in the U.S.A, Canada, and European Union.
