On retrouve actuellement en milieu industriel diverses technologies de scanneurs d’équarris utilisant des configurations soit linéaires ou transversales pour l’optimiser le débitage secondaire. Puisque aucune donnée n’est disponible quant à la performance ou les avantages d’un système par rapport à un autre, Forintek a entrepris de réaliser une étude comparative.
Un échantillon d’équarris a été mesuré dans des conditions industrielles avec trois scanneurs différents, un transversal et deux linéaires, ainsi qu’en laboratoire à l’aide de la technologie de rayon x, servant de référence. La comparaison des rendements obtenus avec chaque scanneur étudié a été réalisée par le biais de simulations à l’aide du logiciel Optitek. Comme la plupart des systèmes de positionnement d’équarris présentent un niveau de précision limité, des erreurs de positionnement ont été appliquées par simulation pour obtenir des résultats réalistes.
Les résultats ont démontré que les erreurs de positionnement ont un impact majeur sur l’optimisation du débitage secondaire. Avec le niveau d’erreur moyen observé en industrie, aucune technologie de scanneur ne se démarque nettement des autres. Toutefois, en améliorant considérablement la précision des systèmes de positionnement, on pourrait observer la tendance suivante : le scanneur transversal s’avèrerait le plus précis avec un niveau d’efficacité de 2 % supérieur au système linéaire à 4 caméras, et ce dernier serait de 2 % supérieur au système linéaire à 2 caméras. La technologie du rayon x offrirait un excellent potentiel d’amélioration par rapport aux technologies actuelles puisqu’elle permettrait d’accroître l’efficacité du débitage de 6 % en ne considérant aucune erreur de positionnement.
The objective of this project was to quantify the lumber value recovery up-lift that is achievable by adding surface defect detection to board profile scanning in sawmill edger optimization. Optimized profile edging solutions of 194 spruce-pine-fir sample boards were compared to optimized edging solutions that took into account surface defects as well as the geometric shape of the board. The edger optimization improvement was found to be marginal. Data analysis showed a benefit of only $0.13 per m3 of processed logs, an equivalent of $237.11 per shift. The findings of this report are mill specific. The value recovery figures were collected in a mill with given log supply, machinery and market orientation. A more significant up-lift in value recovery would likely be obtained for higher valued products produced from larger logs typically processed in coastal sawmills.
This project presents the results of a computer simulation of the recovery obtained from six bucking optimization systems equipped with different scanner and conveyor combinations.
Forty sample stems were scanned and stem models developed to provide input for Forintek’s sawing simulation program, OPTITEK®. Input files of both sawmill machinery and their products were developed based upon the operation of a typical sawmill in the Interior of B.C. Optimized bucking solutions were generated, and sample stems were sawn accordingly. Lumber value and volume recovery data were obtained and enabled a performance evaluation of the six bucking optimization systems.
In this project the affect of both the log conveying system and the type of scanner was considered. Both lineal and transverse conveyor systems were studied and the effects of true shape, partial true shape and XY scanners were modelled. Various combinations of parameters were studied and the annual dollar production for such combinations were computed.
Recommendations are made relating to the different systems studied and how the results may be of benefit to mill optimization.
Sawmilling technology is becoming increasingly complex and, for the past 15 years, optimized systems have replaced human decision-making on the log and lumber processing line. Optimized systems, however, require close monitoring and adequate parameters. Given the increasing shortage of qualified personnel, the use of effective monitoring and control tools is more critical than ever. Monitoring systems are now required to shorten the periods of time during which the primary breakdown process is not controlled.
This research report presents algorithms developed for monitoring the primary breakdown process. The method used to this end is based on available variables for the relevant machine centres. As this method does not require the installation of new sensors, it does not add to the maintenance burden. It should be noted, on the other hand, that certain components of the primary breakdown process cannot be monitored because of a lack of available variables. Such is the case for several mechanical components the monitoring of which requires the installation of specialized sensors.
The algorithms generated by this project use simple mathematical models that can easily be adapted to the majority of softwood lumber sawmills. These models can be integrated into programmable controllers, data acquisition systems, in-house production monitoring software or specialized systems, such as the Smart Mill Assistant system.
The economic potential of the monitoring models can be determined by using optimization system variables and offline monitoring models. The graphical representation of results generated by the models reveals the number of times the primary breakdown process deviated from process parameters, as well as the duration of such deviations. Their economic impact can be calculated on the basis of this information. The economic benefits of real-time monitoring and control systems depend on initial sawmill performance, the skill of sawmill personnel in quickly detecting and identifying process deviations and the time required to solve related problems.
Les technologies utilisées dans l’industrie du sciage sont de plus en plus complexes et les systèmes optimisés ont remplacé les décisions humaines depuis les 15 dernières années. Les systèmes optimisés requièrent un suivi rigoureux et une paramétrisation adéquate. Le personnel qualifié devient rare, ce qui nécessite des outils de monitorage et de contrôle efficaces. Les systèmes de monitorage sont devenus essentiels pour réduire les périodes où le procédé est hors contrôle.
Ce rapport de recherche présente les algorithmes développés pour la surveillance monitorage du débitage primaire. La méthodologie utilisée est basée sur l’utilisation des variables disponibles aux centres de transformation concernés. Cette méthodologie ne nécessite pas l’ajout de nouveaux capteurs, ce qui réduit l’entretien. Par contre, certaines composantes ou parties du procédé ne peuvent être monitorées puisque aucune variable n’est actuellement disponible. C’est en autre le cas pour plusieurs composantes mécaniques qui nécessitent l’ajout de capteurs spécialisés.
Les algorithmes développés utilisent des modèles mathématiques simples et facilement applicables à la majorité des scieries résineuses. L’implantation de ces modèles pourra être faite à l’intérieur d’automates programmables, de systèmes d’acquisition de données, de logiciels maison de suivi de production ou de systèmes spécialisés comme le « Smart Mill Assistant ».
Le potentiel économique des modèles de monitorage peut être évalué en utilisant les variables disponibles dans les systèmes d’optimisation et en utilisant les modèles de monitorage hors ligne (offline). En traçant graphiquement les résultats des modèles, il sera possible d’évaluer le nombre de fois et le temps total pendant lequel le procédé a été en déviation et de calculer le potentiel économique. Ce potentiel économique des systèmes de monitorage et de contrôle en temps réel dépend de la performance de départ de la scierie, de la capacité du personnel en place pour détecter et identifier rapidement les déviations du procédé et du temps requis pour la correction des problèmes.
This study selected acylate monomers/oligomers as the nanoparticle transportation chemicals to produce high value-added wood surface densification products. The effect of nanoparticles in the formulations on the Brinell surface hardness, impact resistance and abrasion resistance was evaluated in this project. It was found that the addition of nanoparticles showed significant effect on mechanical properties of surface densification wood products. Different ratio of monomer/oligomers formulation and their viscosities on the chemical retention and penetration properties were investigated. Lower viscosity formulation presented better penetration and higher chemical retention with same surface densification process.
Two optimized advanced surface densification processes were developed to improve the efficiency and lower the chemical retention thus to decrease the cost of final value-added surface densification wood products. The first optimized advanced densification process that prepared surface-densified wood product by replacing the traditional time-consuming pressurization stage with only a short vacuum process was investigated. Formulations with nanoparticles were successfully impregnated into maple and oak engineered wood flooring planks by using a vacuum time from 30 s to 10 min without further pressurizing during the impregnation process. The properties of these short vacuum process impregnated wood products were also comparable to or even superior to the conventional vacuum/pressure impregnated wood products. The Brinell surface hardness of impregnated maple wood were improved 205% with a 30s vacuum process and oak wood were improved 108% with 60s vacuum process. The second optimized advanced surface densification process contained three steps process. The 1st step consists on application of a layer of resin on the wood surface by roller or curtain coater; the 2nd step is using a 60s vacuum to penetrate the resin into the wood surface to a target depth 1-2 mm; the 3rd step is to cure the impregnated wood with UV/thermal dual in situ polymerization process. The chemical retention decreased drastically with this approach compare to conventional vacuum/pressure impregnation process. 22% improvement of the Brinell surface hardness was found through this low cost approach.
Electron beam (EB) and UV/thermal dual cure process which was industrial viable online in situ polymerization process have been successfully developed to cure the surface densification wood products. The efficacy of EB and UV/thermal dual cure was validated by differential scanning calorimetry (DSC) and photo-DSC characterization. The results showed that EB cure is a powerful instant online polymerization method to cure the fully penetrated chemical surface densification wood products with a relative high capital investment on equipment. UV/thermal dual cure method is a cost-effective approach to polymerize the roller/coater resin application and vacuum penetration surface densified wood products.
In general, this study implied that reduce cost from surface densification process is possible through application of resin by roller/curtain coater followed with a short vacuum process to penetrate the resin into wood surface. This work also implied that in situ UV/thermal dual cure could replace the high cost EB cure surface densification products, which in turn, favour our industrial to adopt this technology cost-effectively.
In an effort to promote the adoption of manufacturing strategies that more closely match the Eastern resource supply, simulation work was conducted with SAWSIM to investigate the benefits of implementing innovative conversion technologies such as: computer optimized bucking (COB), curve sawing technology, and cant optimization technology.
Simulation results for COB clearly indicate that the implementation of computer optimized bucking generates significantly better volume and value recovery than achievable from operator derived bucking solutions.
Comparison of curve sawing and cant optimization simulation results show that both technologies have the potential to improve present efficiency levels by at least 10 percent.
