This addendum completes the presentation of the data and research findings for the project entitled "Development of a high performance OSB panel." Most of the short-term test results and preliminary long-term creep data were summarized in a previous report (Project No. 38-43-M-410) which was submitted to the Canadian Forest Service. This addendum to that report includes new data on rolling shear, revised data on shear-through-thickness, and creep data collected during a load duration of nine months, followed by a three-week creep recovery. In addition, the effects of parameters such as strand length and climatic conditions on the engineering properties are discussed for OSB, waferboard, and plywood panels. Utilization of long strands improved the majority of the properties of OSB panels produced with commercial strands. This improvement, however, was not observed for the OSB panels produced with laboratory strands.
In order to help the plywood industry improve veneer production from new high-tech veneer lathes, this report evaluates present veneer block conditioning methods and techniques for possible areas of enhancement and identifies the need for new innovative instrumentation technology.
Thin circular saws can suffer from a vibration phenomena called critical speed instability. At the critical speed, a resonant condition occurs where a saw can snake slowly from side-to-side producing unacceptably large sawing variation. To avoid this problem, most circular saws operate at 10 to 15 percent below the first critical speed. Unfortunately, this practice limits reductions in saw plate thickness and corresponding improvements in lumber recovery. Recently, several mills have been able to operate guided splined-arbor saws above critical speed. These supercritical speed saws offer significant sawing performance improvements by allowing both high recovery and high production rates. The use of these saws remains rare, however, and very little knowledge is available to guide mills that want to investigate this promising area. This report describes laboratory tests involving two supercritical speed saw configurations which are operating successfully in industry. Detailed descriptions of these configurations are given and guidelines for use are described. Idling and cutting tests were completed to characterize vibrational behaviour and demonstrate sawing performance levels. Tests were done to investigate the effect of changes in saw tensioning, saw tooth design parameters, saw and feed speeds and saw plate thicknesses. Test results confirm that for the sawing configurations tested, operating speeds can be found in the supercritical speed region where stable idling behaviour allows successful sawing. As with conventional saws, sawing accuracy is best at lower feed speeds. However, by operating at supercritical speeds, acceptable sawing accuracy can be achieved at higher feed speeds than are possible using conventional saws. Saw tensioning allows further increases in saw and feed speeds, but is not essential for supercritical speed operation. Changes in saw thickness strongly affect sawing performance levels and lumber recovery. Thinner saws have higher sawing variation and must operate at lower feed speeds than thicker saws. Curves showing the relationship between saw plate thickness, feed speeds and sawing accuracy are presented which can be used to assess the economic benefits of the supercritical speed saws that were tested. Supercritical speed circular saws offer considerable potential to improve sawing performance and increase lumber recovery. These saws allow reductions in saw kerf widths while maintaining high feed speeds and acceptable sawing accuracy.
As a result of its fast growth and abundant availability, aspen has become an increasingly important commercial wood species in the production of oriented strand board (OSB) and veneer-based composites such as laminated veneer lumber (LVL). The purpose of the study described in this report was to determine the effect of conditioning temperature on veneer quality using a 5/8" roller bar, and to determine the optimum bar gaps based on results from previous Forintek studies on aspen veneer peeling.
In 1993, the project entitled "Spray Application Technology" was initiated to improve anti-sapstain spray treatment of lumber by British Columbia sawmills. This project has now been completed with the following milestones accomplished: 1) A better understanding of the spray application process was developed through an investigation of liquid atomization and spray transfer to lumber surfaces. 2) Methods were developed for simulating commercial spray systems using pilot plant facilities at Forintek. 3) Improved longitudinal and cross-chain spray systems were developed at Forintek and their capability to evenly apply spray to lumber at target retentions was demonstrated. 4) Spray technology was transferred to a sawmill which involved installing nozzle configurations developed at Forintek into a new cross-chain spray system at a coastal sawmill. Treated lumber was sampled and the results confirmed original performance expectations. During this project we found that simple changes to existing commercial spray systems, involving the set-up and operation of hydraulic nozzles, are sufficient to significantly improve their performance. Guidelines for improving spray system performance are documented in this report in addition to a detailed explanation of the spray application process.
Spraying
Preservatives - Tests
Preservation - Non pressure processes - Brushing and spraying
This report compares international standards for particleboard, waferboard, OSB, MDF, hardboard as well as cement bonded wood composite panels. Property requirements are discussed and comparisons are made between countries. Formaldehyde emission regulations were surveyed in eighteen countries.
L'alignement précis des équipements de coupe est un moyen recommandé pour assurer la maximisation du rendement matière et de la qualité des produits manufacturés. Les tendances de l'industrie s'orientent de plus en plus vers l'utilisation de scies minces et vers une réduction maximale des dimensions-cibles. Il est essentiel pour la qualité des produits désirés que les préposés de l'entretien et de l'alignement des machines fassent un ajustement de haute précision. Le succès d'un alignement précis dépend en grande partie de la précision des outils utilisés pour accomplir ce travail. Un niveau de précision est calibré de façon telle à permettre de mesurer les déviations du nivelage par unité de millième de pouce. Ce livre propose des formules pratiques que l'expérience en milieu de travail peut mettre à profit. Les méthodes d'alignement s'appliquent à l'ensemble de la machinerie des centres de transformation: équarrisseuse-déchiqueteuse ("Chipper Canter"), scie de tête à ruban avec le chariot, scie de tête à rubans jumelés ("Twin Band"), refendeuse verticale, refendeuse à ruban horizontal, scie de tête circulaire avec le chariot et déligneuse à scies multiples ("Bull Edger").
Composite panels were manufactured from waste wood and recycled, mixed plastics. The effects of key processing parameters including wood fibre content on the mechanical and physical properties of panels produced were evaluated. Chemical treatments of the recycled wood fibre were conducted to improve the dispersion and adhesion of fibres within the matrix. The morphology of the plastic/wood interface was examined critically using a scanning electron microscope (SEM). Experimental work on the hot processing of panels showed that a commercial high speed mixer, (K-mixer) failed to produce a uniform dispersion of the composite materials. The wet process studied presented a good option fro making composites from recycled wood and plastics. A significant improvement in bending strength and stiffness was observed for panels containing up to 60% wood fibre. However, because of the large amount of water required for the wet process, this technique was considered a less desirable approach. Dry processing appears to be the most environmentally sound method and produced panels with mechanical properties similar to those produced by the wet process. The SEM study on fracture interfaces elucidated the relationships between wood fibre/plastic matrix and mechanical properties of panels. Chemical treatments of recycled wood fibres were found to relieve the compatibility problem between wood and plastic, improving the adhesion between these components. Experimental work has also revealed that a commercial microwave generator can be employed to preheat mats prior to hot pressing.
