Environmental product declarations (EPDs) are a standardized way for manufacturers to report quantified environmental impacts of their products. EPDs are developed in line with well-established guidelines from the International Organization for Standardization (ISO) to ensure rigorous and transparent procedures are followed.
The market for hardwood component production is currently affected by low-cost components importation from Asia. Industrial automation is an actual option for the secondary manufacturing industry to counter this situation. Integrating a defect detection system is a complex process and selecting the right system is even more complicated. This study proposes an approach for assessing the defect detection capabilities of different systems as well as a decision support tool to guide the producer toward the adequate equipment. The study is limited to assessing defect detection capacities; the overall system performance, the optimization software and the cutting equipment are not analyzed.
Understanding the origin and characteristics of defects to be detected and the capacities and theoretical limits of vision technology are prerequisites. A sampling with defects that, due to properties such as their small size, are hard to detect, is assessed by each system and the results are compared. To date, the assessed systems are not capable of detecting all defects pertaining to hardwood component production. A decision support tool will make it possible to methodically select the equipment most appropriate to the producer’s needs and leads to an enlightened decision in terms of the producer’s priorities and expectations.
A Roadmap for the Canadian Value Added Wood Products Industry and the Prefabricated Building Systems Industry was completed in 2007 under the Value to Wood Program. Current information is needed to confirm actual industry’s needs for innovation. The project consisted in conducting a Value Added Sector Assessment Survey to update the previous Roadmap.
Information and data were essentially collected through the use of an online interactive survey prepared by the FPInnovations’ economics and markets group. A total of 2,086 industry and research people were contacted to complete the questionnaire. Of that total, 256 respondents returned questionnaires which were kept for analysis.
The study has reviewed the research issues and needs raised by industry respondents. These issues and needs were analyzed and sorted in different themes and then compared to the findings of the 2007 roadmap. The conclusions of the study are notably:
The driving forces of innovation identified in 2007 are still relevant and valid today
o Global competition and consumers needs are the main driving forces leading businesses to seek greater manufacturing and cost efficiencies.
The priorities and research needs identified in the 2007 Roadmap are still pertinent today
o There is a need to increase product development capacities through better design, better finishing, better quality, etc.
o Provide relevant and up to date market intelligence information to support the value added sectors.
In this work, the properties of aspen veneer from two mills (A and B) were compared. The comparisons between the incised veneer and non-incised veneer for mill A were made in terms of veneer thickness, ultrasonic propagation time (UPT), density and MOE. The aspen veneer was further characterized for LVL/plywood products by tailoring veneer grades to the requirements of final veneer products. In addition, MOE-based veneer stress grading and UPT-based veneer stress grading were compared for the aspen veneer. The advantages of MOE-based veneer stress grading over UPT-based veneer stress grading were identified in terms of veneer grade MOE and volume breakdown. The main results are summarized as follows:
1) Aspen veneer properties change from mill to mill. The differences in aspen veneer density and MOE between mill A and B are significant with mill A producing denser and stronger aspen veneer.
2) For aspen veneer in the mill A, the distribution shapes of veneer thickness, UPT, density and MOE between the non-incised and incised veneer are quite similar. Although the differences in veneer thickness, UPT and density between the non-incised veneer and incised veneer are identified as significant, the difference in veneer MOE is not significant due to the effect of both veneer UPT and density. The incised veneer has a slightly higher variation in thickness and is also slightly thicker compared to the non-incised veneer. This could due to the change of lathe settings or the property variation of aspen species as indicated with the veneer density variation.
3) Of the aspen veneer from mill A, using the optimum UPT thresholds, about 27.5 ~ 30.9% can be extracted through veneer stress grading to make 2.0 million psi LVL; about 43.4 ~ 59.9% can be sorted out for 1.8 million psi LVL; and the remaining 12.6 ~ 25.7% can be used for 1.5 million psi LVL or for plywood. It was also found that the incised aspen veneer generates 3.4% less of top stress grade G1 but 16.5% more of stress grade G2 compared to the non-incised aspen veneer if performing the optimum UPT-based stress grading.
4) The MOE-based veneer stress grading not only results in a smaller variation in MOE of each grade, but also higher volume percentages of stress grades G1 and G2 compared to the UPT-based veneer stress grading. This smaller variation in MOE of each stress grade will be very beneficial to the industry and structural applications since higher design stress can be assigned for the wood structural components. Also the higher percentages of stress grades G1 and G2 with the MOE-based veneer stress grading has significant economical implications and should be recognized by the industry.
5) To maximize mill profits, veneer sheets need to be periodically sampled and analyzed using the VGrader software. The optimum grading thresholds for the specific veneer can be established for on-line veneer stress grading based on the current market and requirements of final veneer products, providing a real solution to characterize and make best use of the specific veneer for LVL/plywood products.
Characterizing aspen veneer for LVL/plywood products. Part 2. LVL pressing strategies and strength properties|Manufacturing characteristics and strength properties of aspen LVL using stress graded veneer
In this study, aspen veneer sheets were sampled from a Forintek member mill. Their attributes and properties were measured. Using the optimum stress grading strategy, aspen veneer was segregated into 3 distinct stiffness groups (stress grades G1, G2 and G3) and conditioned to 3 different moisture levels. An experimental design for 3-level four factors comprising veneer moisture content, veneer stress grade, mat pressure and glue spread (or resin level) was adopted. Based on the experimental design, LVL panels with different combinations of four factors were pressed until the target core temperature reached 1050C to achieve full cure followed by a stepwise decompression cycle. The LVL panel final thickness, density, compression ratio and relevant strength properties were measured. After that the effect of aspen veneer moisture, stress grade, mat pressure and glue spread and their relative importance on LVL compression behavior, hot-pressing and strength properties were evaluated using a statistical analysis program. The relationship between LVL panel properties and veneer properties was examined. Finally a method to enhance LVL modulus of elasticity (MOE) to make high stiffness LVL was discussed. From this study, the following results were found:
Aspen veneer is capable of making LVL products meeting 1.8 and 2.0 million psi MOE requirements. Optimum veneer stress grading and proper pressing schedule are two important keys to the manufacture of high-stiffness aspen LVL products. Further, a possibility to make high-grade aspen LVL meeting 2.2 million psi MOE exists by proper veneer densification and optimum veneer stress grading.
The roles of four factors affecting LVL pressing behavior and strength properties are quite different. Glue spread and mat pressure, rather than stress grade and veneer moisture content, are two main factors affecting hot-pressing time taken for the core to reach 1050C. With incised veneer, the moisture from the glue in the glueline affects the rise of core temperature more pronouncedly than the moisture in the veneer, and is more critical to the cure of the glue. High glue spread (44 lbs/1000ft2) not only significantly increases the hot pressing time taken for the core to rise to 1050C, but overall also decreases most LVL strength properties with the pressing schedule used. High mat pressure does not necessarily result in high LVL panel compression due to the high gas pressure that occurs in the core.
Veneer stress grade and veneer moisture are the two predominant factors that mostly affect LVL strength properties. LVL panels assembled with high stress grade result in increases in both flatwise and edgewise MOE and MOR properties rather than shear strength either longitudinal or through-the-thickness. Further, using high stress grade veneer can help make more efficient structural systems in terms of both stiffness-to-weight and bending strength-to-weight ratios compared to using low stress grade veneer. High veneer moisture at 6% impairs all LVL strength properties except edgewise bending MOE.
LVL compression ratio can help link veneer MOE with LVL panel edgewise bending MOE. Overall, every increase of 1% in LVL compression ratio would result in 1% increase in LVL and veneer MOE ratio. With regard to aspen LVL MOE enhancement, using high veneer stress grade gains slightly less than using low veneer stress grade. On average, every increase of 1% in aspen LVL compression ratio results in 0.82%, 1.05% and 1.20% increase in aspen LVL and veneer MOE ratio assembled with stress grades G1, G2 and G3, respectively. In practice, those conversion factors for any specific veneer can be derived based on the correlation between veneer MOE and MOE of target LVL/plywood products made with proper pressing schedules, and be further used to derive requested veneer MOE for each stress grade to perform the optimum veneer stress grading.
Pressing schedules show significant effect on aspen LVL compression behavior and strength properties. Using a pressing schedule with step-wise decompression cycles following the core temperature to rise to 1050C, an excessive compression of LVL in the range of 13.5% to 27.6% is generated which results in high-stiffness LVL with an average MOE of approximate 2.0 million psi for all experiments. Although this pressing schedule has slightly longer pressing time and off-target LVL thickness than current commercial LVL pressing schedules, it helps enhance the strength properties of LVL.
It is recommended that further work should include the effect of different decompression cycles and mat pressure on LVL panel compression ratio and strength properties.
Cette étude a été réalisée pour déterminer le niveau de performance optimal des systèmes de tourne-billes automatiques qui équipent la plupart des entrées d’équarrisseuse dans les scieries de bois résineux.
L’étude a été réalisée avec un système de tourne-billes à rouleaux quadruple installé devant une entrée d’équarrisseuse de type SLI. Un premier test a permis d’établir la performance initiale du tourne-billes et d’identifier les principales sources d’erreurs de rotation. Une première série de correctifs mécaniques ont été apportés en collaboration avec le manufacturier d’équipement, puis un second test de performance a été réalisé. Une certaine amélioration a été notée, surtout au niveau du maintien des billes, après rotation. Une deuxième série de correctifs ont été apportés pour améliorer la précision de rotation dans le tourne-billes avant d’effectuer un dernier test de performance.
Initialement, le système étudié affichait un taux d’erreur de rotation de 36 degrés d’écart-type. Après deux interventions techniques, le tourne-billes a atteint une précision de rotation de 24 degrés d’écart-type. Pour y arriver, certaines composantes mécaniques ont été modifiées et d’autres remplacées dû à l’usure. La programmation des PLC a aussi été revue pour mieux synchroniser les séquences de presses et mieux pré-positionner les rouleaux tourneurs. Une amélioration de rotation simulée de 36 à 24° d’écart-type signifie un gain économique de 2 %, soit 2 $/m³ pour la scierie étudiée. Toutefois le potentiel d’amélioration aurait été deux fois plus important si les erreurs de rotation avaient pu être réduites au niveau de 10 degrés d’écart-type. La précision de rotation aurait probablement pu être améliorée davantage, cependant ce niveau il est assez difficile à atteindre et surtout à maintenir avec la technologie actuelle.
Dans le futur, de nouveaux types d’équipements devraient être développés par les manufacturiers pour obtenir de meilleurs résultats, plus spécifiquement pour le débitage des petites billes à haute vitesse. De plus, les tourne-billes pourraient bénéficier de l’ajout de systèmes de suivi et de contrôle en continu pour en assurer un fonctionnement optimal en tout temps. Des systèmes auto-correcteurs en boucle fermée devraient aussi améliorer la performance des tourne-billes à rouleaux.
A series of plywood and laminated veneer lumber (LVL) panels were prepared using veneers with higher than normal moisture contents in face and back layers. The purpose of the work was to evaluate the effects of self-generated steam on the pressing times and panel warpage. Panels made with 6% and 10% m.c. faces and backs were compared with control panels made with all dry veneer. Thirteen- ply 40 mm (1 5/8 inch) thick panels were evaluated for press times and thin 9.5 mm (3/8 inch) panels were evaluated for cupping and bowing. Normal plywood press temperatures and adhesives were used. All panels were made with incised 3.2 mm (1/8 inch) SPF veneers. The project demonstrated that substantially shorter press times and more dimensionally stable panels can potentially be made using higher moisture content outside veneers.
A series of plywood and laminated veneer lumber (LVL) panels were prepared using incised veneers in the second phase of this two year project. The primary purpose of the work was to evaluate the effects of steam injection on the pressing times. A secondary objective was to expand the study of warpage in three-ply and four-ply plywood which was begun in phase one. Thirteen-ply 40 mm (1 5/8 inch) thick panels were evaluated for press times and thin 9.5 mm (3/8 inch) and 12.5 mm (1/2 inch) panels were evaluated for cupping and bowing. Press temperatures of 150 degrees C, 175 degrees C and 204 degrees C were used with a commercial adhesive mix for the LVL study while normal plywood pressing conditions were used for the plywood. For the plywood warpage study, the effect of lathe check orientation and species mix were evaluated. The lathe check orientation had little effect while the surface veneer species had a pronounced effect on the warpage in the plywood. Steam used for injection was heated to 260 degrees C at 450 KPa (65 psi) with a super-heater. All panels were made with incised 3.2 mm (1/8 inch) SPF veneers. The project demonstrated that steam injection can shorten press times by fifty percent if incised veneers are used.
This EPD addresses products from multiple manufacturers and represents an average for the membership of the Western Red Cedar Lumber Association (WRCLA), a non-profit trade association representing manufacturers of western red cedar products. This average is based on a sample that included two lumber mills in British Columbia (BC), combined with recent secondary data on western red cedar resource extraction from the Athena Institute. The total data represents 20% of western red cedar decking production in the year 2007.