Thesis (Ph.D.) in Forest Resources--University of Maine, 2008. / Includes vita. Includes bibliographical references (leaves122-133 ).

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British Columbia's plywood industry between 1913 and 1935 bore little relationship to the industry of the post-World War II period. In 1913, the Canadian Western Lumber Company's Fraser Mills plant manufactured Douglas fir plywood, but until the late 1930s the largest part of its production was used in door manufacture. Two cottonwood plywood manufacturers, Laminated Materials Company (1913–1931) at New Westminster and the British Columbia Veneer Works (1928–1945) at Nelson, sold their plywood for interior wall paneling and specialty uses such as packing crates. The opening of the H. R. MacMillan Export Company's (MacMillan Bloedel) Vancouver plywood plant in 1935 and its Alberni plant, built in 1942, began a new era of plywood production. Sanded Douglas fir plywood dominated sales. The major producers (MacMillan Bloedel, Canadian Forest Products, Crown Zellerbach, British Columbia Forest Products, and Weldwood), assisted by the Plywood Manufacturers Association of British Columbia, targeted customers and created demand for waterproof Douglas fir plywood. The major producers established a network of wholesale warehouses across Canada and used these warehouses as a competitive strategy to develop and influence sales. The major manufacturers after World War II used the high profits generated by Douglas fir plywood to assist their expansion into integrated forest products. Each company chose a different strategy of expansion and adapted its plywood production to suit its corporate goals. Plywood became one product among several and declined in importance for each company. By the 1970s substitute products such as oriented strand board were being promoted as replacements for plywood. Cheaper production costs and the use of waste wood fibre, instead of high quality Douglas fir logs, meant that government and industry favourably viewed the substitute products. The high value of old growth Douglas fir logs and increased costs in all aspects of production resulted in the closure of all but one coastal plywood plant, Richmond Plywood, by 1999. Exports were a small percentage of total plywood sales and did not compensate for declining domestic demand. The interior plywood industry was re-established in 1951 with the opening of Western Plywood's Quesnel plant. A number of plants, scattered throughout the interior, produced plywood using small logs and species other than coastal Douglas fir. Production was mainly sheathing used to clad building floors, roofs, and walls. The scattered nature of plant location, cheaper log costs, small log processing technology, and different harvesting tenures contributed to the success of interior plywood production. The large producers closed their coastal plywood plants arguing that production costs were too high and that other products were replacing plywood in the marketplace. The prosperity of interior plywood manufacturing suggests that the coastal industry stopped production because neither government nor manufacturers saw any reason to seek viable alternatives. The forest industry's diverse nature and its perception of future, based on past activities, supported the closure of the coastal plants and the continued survival of the interior plants within a new forest economy. / Graduate

Three particle boards, one flake board, one multi-layer board, and a plywood panel, all of 3/8-inch thickness, were overlaid with 1/20-inch Philippine mahogany veneer, using a urea-formaldehyde adhesive. Both non-overlaid and overlaid boards were subjected to physical and mechanical tests involving the glue line and the boards themselves. Results of the glue-line shear test indicated that glue-line failure between the veneer and the boards only occurred in the boards of higher density. Overlaying the boards decreased dimensional change in a plane parallel to the length of the board but slightly increased it parallel to the width of the board. Boards composed of flakes had better strength properties than those composed of particles. No delamination of the board occurred during accelerated aging; however, deterioration in the board core was extensive. In general, overlaying the boards tended to minimize differences in strength properties between boards, and improved the strength properties so as to be almost comparable to those of plywood. Overlaying decreased warping in the boards. Some physical properties of the boards, such as resistance to warping and face-checking, were more satisfactory than those of plywood. / Forestry, Faculty of / Graduate

A combination of many grades of veneer may be jointly produced by peeling any one type of logs. This means that the plywood manufacturer can not really know the profit margins of the panels he produces. And for most of the manufacturers, the cost of the logs constitutes about 65% of the total cost of producing the plywood panels. Consequently, the manufacturer finds it very difficult to select his sales strategy and to price his panels. The plywood manufacturer also has opportunities to minimize his log cost and processing cost by selecting the right combination of logs to peel and using the right constructions in laying up the panels. Linear programming techniques are used in this study to provide an approach to the above mentioned problems for a selected plywood manufacturer. Through this, it is hoped as well to provide an examination of the way to use linear programming techniques and an evaluation of their usefulness as management tools in plywood manufacturing. A survey of the reported experience of some plywood manufacturers indicated that the use of L. P. had been instrumental in saving some hundreds of thousands of dollars per annum for some manufacturers. An L. P. model was constructed for the largest of the four mills of the Case Company, using the operating situations predicted for the year 1967. Such problems (and their solutions) as were encountered in defining, identifying and measuring the variable process costs and the need for making simplifying assumptions were examined. The L. P. model seeks to optimize the choice of panel output, the choice of log input and the choice of panel constructions simultaneously because these three decisions are interrelated and somewhat interdependent. The L. P. analysis suggests that about 30% of the dollar sales of the Case Mill in 1967 were made in unprofitable (thin) panels. Even after allowing for possible over estimation in measuring the variable processing cost, this may call for a thorough re-examination of the sales strategy and the panel pricing system. To produce the panel output selected for 1967, the best log combination apparently includes the use of a much higher proportion of Fir Peeler #2 and Sawlog #3, Interior Fir and Hemlock-Balsam Mix than was used by the Company in its mill. Also, the model suggests proportions of Fir Peeler #1, #4 and S. F.P. might be much lower than what the Company tended to use. These tentative findings may have significant implications for choosing log acquisition policies. The model suggests the choice in panel construction may be to peel Peeler logs for .104" high quality veneer, Interior Fir for .130" veneer and other low quality logs for .171" core veneer. It also suggests down-grading some veneer and using some subsidiary panel constructions so as to utilize fully the total supply of veneer from the logs peeled. The usefulness of the L.P. analysis is fully realized by making a comprehensive post-optimal analysis of the sensitivity of the optimality of the solution to various changes in the log supply and/or panel demand and/or processing cost situations. This analysis may enable the company to determine which of the operating factors seem crucial in determining the profitability of the panels and what may constitute the best log combination to use. From this, the manufacturer could possibly know when and how to adapt his program of operation in response to any future changes in (or any revision in the forecast of) the operating situation. This analysis is also helpful in gauging the importance of the assumptions made when constructing the model. No comprehensive sensitivity analysis was carried out in this study. However, recommendations regarding appropriate post-optimal analyses are presented. Lastly, the study concludes by presenting an L. P. model of possible use to analyze the four mills of the Company together, recognizing the possibilities of specialization and cooperation among the mills. / Business, Sauder School of / Graduate

This work follows successful research by staff members at Forintek Canada Corp. in modifying and extending phenol-formaldehyde (PF) plywood resins with powdered tree foliages and barks. In the present study, two urea-formaldehyde (UF) resins, one commercial and one laboratory synthesized, were modified at 15, 30 and 45% addition levels with finely ground white spruce [Picea glauca (Moench.) Voss] foliage or western hemlock [Tsuga heterophylla (Raf.) Sarg.] bark. Two five-ply Douglas-fir [Pseudotsuga mensiezii (Mirb.) Franco] test plywood panels (38 x 38 cm) were made at 32kg/l00 m² double glueline spread level, six and ten min pressing time at 149°C. The commercial and laboratory synthesized wheat flour extended UF resins were used as controls. Shear strengths and wood failure percentages were recorded for sets of test specimens after conditioning at 22°C and EMC of about 6% (Dry test), one vacuum pressure cycle, five vacuum pressure cycles and boiling cycle. Most formulations with the commercial UF resin containing foliage or bark yielded good bond quality (wood failure and shear strength) similar to the control when tested dry and after one vacuum pressure cycle. Following multi-cycle testing, one formulation containing foliage gave similar wood failure percentage to the control. Two formulations containing bark improved glue bond durability yielding 3 to 12% higher wood failure than the control. Results with the laboratory resin were not as good, showing bond quality lower than with the commercial UF formulation. No formulation survived boiling treatment implying that no modification among those used improved UF resin durability under conditions of high moisture and-temperature. Both UF resins were successfully extended by various foliage and bark additions. It was found that both materials can be used as partial substitutes for the conventional extender wheat flour up to the 40% level. This information may be of use to some developing countries that import wheat to flour-extended UF resins used to bond interior grade plywoods. Such countries could benefit by making use of local tree foliages or barks. / Forestry, Faculty of / Graduate

One factor of wood loss in the manufacture of plywood is implicit in the form of excess thickness in plywood due to the choice of veneer thicknesses and plywood designs used in assembly. The thickness and designs currently in use appear to have come largely from tradition and there is no evidence in the literature to show what constitutes the most economical veneer thicknesses and plywood designs for a mill. The problem of determining them is very complex since many types of plywood are assembled in each mill as some integral multiple combination of a few veneers satisfying the 'balanced design' and other structural specifications. The consumption of logs is dependent on the excess thickness in plywood and the economics of the mill further depend on how efficiently a given set of veneers and designs are used to satisfy the orderfile requirements. In this dissertation, these aspects of the Plywood Design and Manufacturing (PDM) problem are addressed using a mathematical programming approach. The problem of finding the optimal veneer thicknesses, associated plywood designs and product mix is formulated as a non-linear mixed integer mathematical programming model. Utilizing the structure of the constraints and by selecting appropriate variables to branch on, it is demonstrated that the PDM problem can be solved efficiently through an implicit enumeration algorithm involving a tree search procedure. The subproblem to be solved at each feasible node of the tree is a Linear Multiple Choice Knapsack (LMCK) problem whose solution can be obtained explicitly following its coefficient structure. A computer code is written in FORTRAN for the implicit enumeration algorithm. Data obtained from a plywood mill in B.C. is analysed using the PDM model and this code. It is demonstrated that the annual net revenue of the mill can be substantially increased through the use of the PDM model. The PDM model is further extended to mill situations involving more than one species and varying orderfile requirements. The model is reformulated in each case and it is demonstrated that essentially the same tree search procedure can be used to solve all these models. When the orderfile is independent of species, the subproblem to be solved at each node of the tree is a Generalized Network problem. It is shown that this Generalized Network problem can be reduced to a Generalized Transportation problem utilizing the structure of the coefficients and solved as an ordinary Transportation problem. When the orderfile is dependent on species, the subproblem decomposes into several Linear Multiple Choice Knapsack problems. If more than one species of veneer can be mixed within a plywood panel, the subproblem is a linear programming problem. The PDM model is further shown to be a special case of a disjunctive programming problem. Following the development of the PDM model, methods to determine the efficiency of plywood designs and the optimum number of veneer thicknesses for a plywood mill are developed. / Business, Sauder School of / Graduate

Thesis (Ph. D.)--Michigan State University. Dept. of Forestry, 1981. / Description based on print version record. Includes bibliographical references (leaves 202-212).

Den svenska byggbranschen strävar efter ständig förbättring och utveckling genom nya byggtekniska lösningar och material.Det finns olika varianter av konstruktionsplywood där bredd och tjocklek varierar. De vanligaste måtten är 12x900x2500 mm och 12x1200x2500 mm, det finns också en nyare utformning av plywood som heter Ergo-plywood, med måtten 12x618x2400 där långsidorna är falsade för en enklare och effektivare montering likt den som sker vid klickgolv.För att besvara frågor om hur plywoodskivornas utformning påverkar arbetsmiljön och hur hanteringen av materialet skiljer sig åt planerades en undersökning där enkäter besvaras av personer i tre olika yrkesgrupper: träarbetare, arbetsledare och projektörer/konstruktörer. Denna del av examensarbetet har tyvärr inget resultat. Trots påtryckningar har inte en enda enkät besvarats.I en undersökning av plywood visar examensarbetet hur lönsamheten och arbetsmiljön varierar för tre olika utformningar av plywoodskivor. Rapporten beskriver skillnader och likheter för de olika utformningarna, med målet att hitta den lönsammaste utformningen.I en ekonomisk effektivitetsstudie beräknas de olika fördelarna som tydligt redovisas i tabell- och diagramform. Beräkningen som är utförd i Excel är bifogad i examensarbetet och är tillgänglig för användning vid egna beräkningar.Examensarbetet visar hur kostnaden för ett regelverk i en bärande konstruktion är beroende av centrumavståndet där ett mindre avstånd mellan reglar ger en större materialåtgång, ett mindre centrumavstånd ger möjligheten att använda sig av en mindre dimension på reglar, samt hur detta påverkar slutpriset på konstruktionen.Resultatet visar att vid höga indirekta arbetsplatskostnader är Ergo-plywood den lönsammaste, på grund av dess effektivitet, Ergo-plywood är också den skiva som medför den bästa arbetsmiljön. 1200 mm bred plywood är vid materialinköp den billigaste skivan, dock är den långsammast att montera. 900 mm bred plywood har ett relativt högt kvadratmeterpris, dess utformning innebär att regelverket måste vara uppbyggd med centrumavståndet 450 mm som leder till högre totala kostnader när regelverket beaktas som en del i beräkningen. / The Swedish construction industry strives for continuous improvement and development through new construction technology, solutions and materials.There are different types of construction plywood where width and thickness vary, the most common dimensions are 12x900x2500 mm and 12x1200x2500 mm. There is also a newer design of plywood called Ergo-plywood, with the dimensions 12x618x2400. The long sides of Ergo-plywood are grooved for a simpler and more efficient installation similar to click floors.To answer questions about how the design of plywood boards affects the working environment and how the handling of the material differs, a survey was planned where questionnaires were to be answered by professionals in three different occupational groups: woodworkers, supervisors and designers. This part of the thesis unfortunately has no result, despite several reminders, none of the questionnaires was answered.In a study of plywood, the thesis shows how profitability and the working environment vary for three different designs of plywood boards. The report describes differences and similarities for the different designs, with the goal of finding the most profitable design.In an economic efficiency study, the various benefits that are clearly reported in tabular and diagrammatic form are calculated. The calculation performed in Excel is attached to the thesis and is available for use in own calculations.The thesis shows how the cost of a set of joists in a load-bearing structure depends on the center distance where a smaller distance between load bearing joists gives a greater material consumption. A smaller center distance also gives the opportunity to use a smaller dimension of joists. The thesis also shows how this affects the final price of the structure.The results show that at high indirect workplace costs, Ergo-plywood is the most profitable, due to its efficiency, Ergo-plywood is also the board that brings the best working environment. 1200 mm wide plywood is the cheapest board when buying materials, but it is the slowest one to assemble. 900 mm wide plywood has a relatively high price per square meter, its design means that the regulations must be built with a center distance of 450 mm, which leads to higher total costs when the set of joists are considered as part of the calculation.

Natural fibers like kenaf, hemp, flax and sisal fiber are becoming alternatives to conventional petroleum fibers for many applications. One such applications is the use of Non-woven bio-fiber mats in the automobile and construction industries. Non-woven hemp fiber mats were used to manufacture plywood in order to optimize the plywood structure. Hemp fiber mats possess strong mechanical properties that comparable to synthetic fibers which include tensile strength and tensile modulus. This study focuses on the use of hemp fiber mat as a core layer in plywood sandwich composite. The optimization of fiber mat plywood was done by performing a three factor experiment. The three factors selected for this experiment were number of hemp mat layers in the core, mat treatment of the hemp mat, and the glue content in the core. From the analysis of all treatments it was determined that single hemp mat had the highest effect on improving the properties of the plywood structure.