Evaluation techno-economique des effets de l'application de charges au-dessus des piles de bois pour reduire le declassement du melange epinette-pin-sapin
Conversion factors in comparative and standardized units are proposed for Eastern Canada forest products industry data. Information on wood measurement, wood properties and wood products are the most common "missing links" in the calculation of wood consumption and wood product yield. In this research, Forintek was commissioned to improve the accuracy and usefulness of OMNR'S Forest Industry Mill Information System (FIMIS) database. This publication contains information specific to the resource sizes, species, technologies and units used by the lumber and composite board industries in Ontario, Quebec, New Brunswick, Nova Scotia and Newfoundland. The resulting forest products industry statistics respond to industry, research and government who need to convert performance data into units and ratios.
Des facteurs de conversion en unités comparables et normalisées sont proposés pour des données d'usines de produits forestiers de l'Est du Canada. Les informations sur le mesurage du bois, les propriétés du bois et les produits du bois permettent de combler les lacunes dans le calcul et l'évaluation statistique de la consommation de bois et du rendement en produits du bois. Un des mandats de cette recherche consistait à améliorer la précision et l'utilité de la base de données Forestry Industry Mill Information system (FIMIS) du MRNO. Cette publication contient les dimensions, les espèces, les technologies et les unités de mesure spécifiques à la ressource exploitée dans les industries de bois de sciage et de panneaux composites de l'Ontario, du Québec, du Nouveau-Brunswick, de la Nouvelle-Ecosse et de Terre-Neuve. Cette contribution sur les statistiques forestières s'adresse aux industriels, aux institutions de recherche et aux organismes gouvernementaux qui désirent convertir des données d'usines en unités de mesure et en proportions. Publication Speciale SP523F
Wood failure evaluation is the key criterion for predicting the long-term durability of plywood. At present, the conventional visual method for plywood wood failure evaluation is slow and subjective. Even experienced evaluators can show significant differences in their evaluations on the same plywood specimen and an individual evaluator can make different wood failure estimates on the same specimen at different times. Differences among evaluators can be as high as 50% for some samples. Evaluations can be influenced by room lighting, the wood species, sample treatment, and readings from prior samples. An automatic wood failure evaluation system using image analysis techniques could potentially be programmed to consider all the variables and respond with consistent wood failure values regardless of the experience level of the machine operator. This report describes the results of a one-year project in which a system for automatic plywood wood failure determination was investigated. A color optical imaging system was assembled and the preliminary work of compiling suitable algorithms was completed with promising results. The imaging system was 100% effective in reproducing individual sample values. Samples were sorted according to plywood type and test method to develop appropriate program algorithms for each category. The wood failure program was then further developed to automatically detect wood species and test method, thus avoiding the need for specimen separation prior to evaluation. Based on nearly 1200 samples in four categories, the differences in average values of wood failure between human evaluation and machine vision were found to be less than plus or minus 5%. In addition, a minimum of 85% of individual machine readings fell in the plus or minus 15% range of deviation expected of human wood failure readers. The imaging system was more accurate for light-colored specimens (i.e., Canadian Softwood Plywood) than darker-colored specimens (i.e., Douglas fir ) and for specimens where resin had been applied by spray. In order to make the imaging system more reliable and robust, the algorithm parameters now need to be fine-tuned based on a larger sample database.
Across North America the amount of tensioning used in bandsaws varies drastically. Sawblades tensioned to fit circle gauges from 28 feet to 80 feet in diameter are in regular use and performing very well. This raises the questions as to what is the right amount of tension and what effect does it have on cutting accuracy. In this study, the cutting accuracy of five sawblades, with varying levels of tension, have been measured and compared. The results show that little change occurs in cutting accuracy once enough tension has been put into the blade for it to fit an 80-ft circle gauge.
This study compares the machining properties of 15 individual species within B.C.'s SPF and hem-fir groups demonstrating the benefits of sorting by individual species. In addition, the machining properties of B.C.'s under-utilized species (e.g., trembling aspen, black cottonwood) are compared to those of well-established softwood species (e.g., Douglas-fir, western hemlock). Finally, the study determined the average force necessary to withdraw two types of fasteners (nail and screw) from each of the wood species.
To develop new projects in the field of sawmill optimization, 21 sawmills were surveyed in British Columbia and Alberta. The project ideas were intended to help the sawmill industry to improve lumber recovery. This report describes the survey methods used, the type of sawmills included in the study, the specific research projects proposed, and the method by which priorities were assigned to projects.
Experiments were conducted to evaluate steam-injection pressing of plywood and LVL using saturated and superheated steam conditions. Three steam-injection times of one, two and three minutes were used to prepare 7-ply plywood and steam-injection times of three, five, seven, and nine minutes were used to prepare LVL. The results showed optimum pressing times were achieved with the steam-injection times of one and two minutes for the 7-ply plywood and seven minutes was found to be an optimum steam-injection time for LVL. All the panels prepared under a variety of steam conditions exhibited excellent bond quality and the average % wood failure was greater than 80% in all cases. For the preparation of the 7-ply plywood and LVL, using the optimum steam-injection times for both superheated and saturated steam conditions, the pressing time was reduced by over 30% compared to conventional platen heating. An economic analysis of return on investment for thick plywood products and LVL shows the pay-back period for retrofitting an existing plywood or LVL press for steam injection is less than three months.
In Western Canada, major problems in drying sub-alpine fir (Abies lasiocarpa (Hook)), either alone or as part of the spruce-pine-fir species mix, have been largely attributed to the occurrence of wet-pocket wood in this species. The species is notorious for containing wet pockets that significantly extend the drying time and make it difficult to create a uniformly dried end product. Some of the problems are usually caused by the initial high and variable moisture contents, which causes the lumber charge to have wide variations in final moisture contents after drying. Since there has been an increase in harvesting of sub-alpine fir in recent years, the industry is faced with drying larger amounts of this species. Therefore, there is a need to develop suitable schedules for sub-alpine fir. The objective of this study was to develop or improve current drying schedules for sub-alpine fir containing wet-pockets based on wood properties and drying behaviour by manipulating drying conditions. Twenty-three kiln drying runs, using Forintek's experimental 3-foot kiln, were performed using different combinations of air-drying, pre-steaming and conditioning in the drying schedules. Air-drying phase of the schedule was 0-, 4- or 8-weeks; pre-steaming phase was 0-, 4- or 8-hours; and, conditioning phase was 0-, 2- or 4-hours. Basic density, initial and final moisture content distributions, were determined for each lumber load as well as an estimation of the amount of wet-pockets were recorded. Moisture diffusion was examined for wet-pocket wood with different pre-steaming periods. Use of hand-held moisture meters to determine the final moisture content of the wood was examined. In general, air-drying can significantly reduce lumber kiln drying time. The air-drying period for this study was during the summer months. The effect of 4-weeks air-drying and 8-weeks air-drying are similar. Air-drying can improve final moisture content distribution within each run. There is a reduction of over-dried and under-dried percentage with air-dried lumber when followed by kiln drying. Pre-steaming slightly increased the drying rate when average MC of the load was below about 40%. Pre-steaming has no significant effect on final moisture content distribution with in each run. The diffusion of moisture in the wet-pocket wood appeared to increase when the wood was pre-steamed. Based on the results in this study, the best strategy for drying sub-alpine fir is using air-drying in combination with the mill's conventional schedule. This report provides details of the different combinations which mill personnel can use to develop their own drying strategy to improve the quality and uniformity of sub-alpine fir lumber.
