To develop a method for establishing a fibre budget in a sawmill, we selected a sample of stems and had it converted into lumber. We also took advantage of this opportunity to pursue this exercise somewhat further by quantifying volume and value recoveries for the sample, as well as the various performance indicators used to monitor the lumber manufacturing process.
A specialized company measured and weighed the stem sample to determine mass/volume ratios. The stems were then bucked and debarked, and we recovered all resulting products and by-products to measure and weigh them, and develop the different bucking ratios. The debarked logs were sawn in a mill and, as for bucking, all resulting products and by-products were quantified, weighed and classified. We used all product and by-product volumes or weights to generate the various indicators used to monitor operations and process performance.
With products and by-products suitably quantified, we introduced product values, which allowed us to determine the value of all products and by-products generated from the conversion of a given log or stem sample. In addition to making it easier to control production value, these performance indicators can be used to compare values generated from similar samples with modified production criteria, or different samples processed through the same production criteria. The ultimate objective is to measure the effects of changes in the resource or the sawmilling process.
The purpose of this study was to determine the effects on lumber surface and chip quality of knife bite, knife velocity and the number of knives in the conversion of black spruce logs [Picea mariana (Mill.) B.S.P.] with chipper-canters equipped with bent knives and disposable knives. Lumber quality is determined by losses due to trimming necessitated by large knife marks and wood tear-out, which cause board downgrading. Chip quality is determined by the proportion of fine particles in chip classification tests (length and thickness). Twelve tests were conducted with the following variables: 22.2 mm and 28.6 mm knife bite; 3 and 6 knives; and 762.2, 1219.5, 1676.8 and 2131.1 m/min knife velocity. Preliminary results showed that chip fines contents increased with knife velocity while surface quality was not significantly affected. Mean chip length and mean chip thickness decreased as knife velocity increased and knife bite increased. The tests were performed on logs 2.54 m in length and 15 cm in diameter at temperatures in the 15-25°C range.
The proportion of fines was lower with bent knives but it tended to increase when knife velocity increased. There was no difference in the proportion of fines for a given knife bite but it was affected by the number of knives. The proportion of chip fines increased with knife velocity. Mean chip thickness decreased as knife velocity increased; it also decreased with an increasing number of knives. With all other parameters being equal, mean chip thickness was greater with bent knives. As knife bite increased, so did mean chip thickness. Mean chip length generally decreased as knife velocity increased; it also decreased as the number of knives increased. For a given number of knives, mean chip length was greater with bent knives. As knife bite increased, mean chip length increased too.
Unlike the results obtained with mean chip length, mean chip thickness was always greater with primary cuts than with secondary cuts. Differences between mean chip thickness in primary and secondary cuts were less than 1%. It was therefore considered reasonable to analyze chips from both cuts as a single lot without affecting mean chip thickness. Surface tear-out generally decreased as knife velocity increased. Greater knife bite increased surface tear-out. A greater number of knives decreased surface tear-out. Bent-type knives decreased surface tear-out by comparison with disposable knives under all conditions. The proportion of boards qualifying as Premium grade with less than 1/32” wood tear-out was less than 30% for 1.640” target size and 10% to 40% for 1.700” target size. For Premium grade accepting wood tear-out less than 1/16”, the proportion of acceptable boards was 10%-50% (1.640”) and 20%-60% (1.700”). For Premium grade accepting wood tear-out less than 1/8”, the proportion of acceptable boards was 50%-80% (1.640”) and 60%-90% (1.700”).
Under all conditions, cutting knife and counter-knife rake angles were lower at the entry point into the wood than at the exit point. Cutting knives always had larger angles than counter-knives. Finishing knife rake angles were always greater at the entry point than at the exit point. With bent knives, cutting knife angles were smaller but counter knife angles were always greater than those of disposable knives; finishing bent knife angles were greater than those of disposable knives.
Except at 1200 m/min knife velocity, bent knives were associated with higher monetary losses than disposable knives. A head equipped with six disposable knives seemed to incur lower losses at lower knife velocity, and a 22.2 mm knife bite seemed to result in lower monetary losses than a 28.6 mm knife bite.
Note: The calculations of the monetary losses were based considering that the totality of the lumber pieces can be classified Premium. In reality, around 30% of the pieces can be Premium; natural wane, rot, knots and other defects cause degrade without being damaged by the debarker or the canter. Losses must then be reduced to 30% of their value if the entire production is considered.
Le contrôle de la qualité des produits est effectué dans la majorité des scieries, mais à divers degrés d’intensité. Il est souvent effectué à la fin du procédé, généralement à l’usine de rabotage, lorsque les produits sont prêts à l’expédition et est rarement basé sur des procédures statistiques standardisées spécifiques à chaque poste-clé de transformation à la scierie. L’objectif général du projet est d’établir des procédures de contrôle du procédé qui permettent d’obtenir des équipements fonctionnant avec une efficacité optimale et ce pour toutes les étapes importantes du procédé de transformation du bois dans une scierie. Les résultats sont présentés sous la forme d’une série de guides portant chacun sur des procédures particulières au poste de transformation visé. Ces guides s’adressent aux contrôleurs de qualité des scieries et à toutes les personnes en charge de l’optimisation des procédés. Ils constituent une source d’information pour établir un programme de contrôle du procédé.
Le présent document est consacré au débitage primaire. Les sections du guide couvrent les points suivants :
Mise au point : cette section détaille les éléments importants à vérifier pour assurer le fonctionnement adéquat de l’équipement. À cet effet, une attention particulière est portée aux systèmes d’alimentation, de scannage et de positionnement de la machine.
Opération : cette partie survole le rôle de l’opérateur (systèmes manuel et optimisé) et s’attarde ensuite à cerner les paramètres d’optimisation dont la compréhension et la maîtrise sont cruciales au fonctionnement optimal de la machine.
Contrôle de qualité : cette section propose des procédures simplifiées de contrôle journalier sur des points critiques de l’équipement. On s’assure ainsi de maintenir le niveau de performance du débitage primaire à son meilleur.
Performance : cette section du document fournit une méthode pour faire l’évaluation de la performance d’une ligne de débitage et comparer les résultats obtenus aux résultats standards de l’industrie.
Des annexes proposent des formulaires pour les différentes méthodes proposées.
In both conventional and dehumidification drying, airflow is essential to transfer the heat needed to warm up the lumber, evaporate water from the wood surface and remove the resulting moisture. Faster airflow means greater energy transfer at the wood surface. It also means faster water removal from the wood surface. How much productivity can be gained from increasing air velocity by 100 ft/min?
The objective of this study was to determine the effect of air velocity on productivity, lumber quality and energy consumption in the drying of spruce-pine-fir (SPF) construction lumber in eastern Canada. The authors initially used the Drytek modeling software to evaluate the effect of air velocity on drying productivity. Modeling studies on balsam fir, jack pine and black spruce demonstrated a positive effect of increased air velocity on drying productivity.
They conducted laboratory tests on 2x4x8-ft lumber from the Lac Saint-Jean, Quebec area. These tests used the same moisture content-driven schedule at four different air velocities, i.e.: 300, 600, 900 and 1200 ft/min.
The study showed that, on the basis of initial moisture content (MC) of 40% and a final MC of 15%, a 100-ft/min increase in air velocity raised productivity by approximately 2%. Gains in drying time were obtained only from the green state down to the fibre saturation point (FSP), which corresponds to 25-30% MC. Higher air velocity did not reduce drying time below FSP. Consequently, the gains obtained from raising air velocity by 100 ft/min are greater when the initial moisture content is higher than 40% than when it is below that level.
Final moisture content variations between and within pieces were comparable at the different air velocity levels, as a result lumber quality was also comparable. A visual assessment of lumber distortion in the piles showed no significant difference.
The specific power consumption of the ventilation system was 0.1, 0.2, 0.6 and 1.0 kWh/kgevaporated water respectively at air velocities of 300, 600, 900 and 1200 ft/min, but this level of specific power consumption is only applicable to the laboratory kiln used in the tests. Preliminary industry data suggest that specific power consumption for black spruce would be 0.06, 0.11, 0.14 and 0.18 kWh/kgevaporated water for the same air velocities in the more efficient industrial kilns. These values will need to be confirmed in the second phase of the study.
Economic calculations on the productivity gains obtained from higher air velocities indicate that annual revenues from a given kiln capacity can be increased. A productivity gain of 2% resulting from a 100-ft/min air velocity increase yields additional revenues of $1/Mbf of dry lumber, assuming a dry/green price differential of $50/Mbf. At a $100/Mbf price differential, the revenue gain becomes $2/Mbf. Additional costs related to high air velocity should however be subtracted from such potential gains. For example, the modification or addition of baffles, or the adjustment of fan blades may lead to higher air velocity at minimal cost to the company; and power consumption will not increase significantly, as the system continues to move the same quantity of air per unit of time. If, on the other hand, a more powerful ventilation system is required, this will involve some capital cost as well as increased power consumption per unit of dry lumber. Mills should take these additional costs into consideration before deciding whether to modify the equipment.
To minimize electrical energy costs when increasing air velocity, producers can also adjust air velocity in relation to the different phases of the drying schedule, given that fan speed can be reduced when the lumber moisture content falls below the fibre saturation point. A previous Forintek study showed that lower fan speed below the FSP level could reduce power consumption with no negative effect on kiln productivity. The current study confirmed that higher air velocity did not result in productivity gains below the FSP level. Mills using high air velocities would therefore generate substantial cost savings by lowering fan speed in the final phases of the cycle. This would require some means to identify when the FSP is reached and the use of variable speed drives for the air circulation system.
As part of this study, we used a software program to model airflow in one of Forintek’s experimental kilns with an actual lumber load. We then compared air velocity on the exit side of the stack according to the model versus actual velocity as measured in the kiln. As the values obtained from the two sources were similar, we believe that our model may prove a very useful tool to simulate the effect of modifying kiln geometry. It will allow producers to assess the effect of modifications such as new or modified baffles or a different roof angle on airflow before they make any decision.
In summary, lumber manufacturers should keep the following points in mind before deciding to modify the airflow system:
Ensure sufficient air space in-between rows with good stickering and stacking practices, as well as proper use of baffles.
Optimize fan blade angle in order to use installed motor power as efficiently as possible.
Ensure that the system can provide sufficient heat energy. With increased airflow, the kiln will require the same amount of heat energy to dry a given load, but over a shorter period of time.
Consider installing a variable-speed drive to reduce airflow below the fibre saturation point, thus reducing energy consumption.
Consider the effect of air velocity on systems based on the temperature drop across the load (TDAL). Adjustments to airflow may result in changes to TDAL measurements and require modifications to the drying schedule.
Further work is needed to finalize the recommendations based on this study. Over the coming year, we will run tests on balsam fir and jack pine to determine potential productivity gains from increased airflow with these species. We will also analyze in more detail how power should best be managed and used under industrial conditions. These follow-up studies will be conducted in collaboration with Hydro Quebec’s Laboratoire des Technologies de l’Énergie (LTE), in Shawinigan, Quebec as part of our joint Électrobois II program.
Ce document explique la mise en place simplifiée d’une carte de contrôle, la fréquence de prise de mesures et quantifie la qualité de la fabrication par des calculs simples. Cette méthode de prise de données est rapide et peut donc être utilisée pour plusieurs postes de travail. De même, la facilité d’analyse des données en cours de production permet de détecter une tendance ou un problème rapidement; une intervention rapide peut donc être faite et permet d’éviter des erreurs de production coûteuses.
De plus, les notions de statistiques sont décrites avec l’aide d’exemples pratiques. Des tests statistiques permettent de déterminer si une modification à un équipement a amélioré de façon significative le procédé.
Response Surface Design (Design-Expert 6.0.5) was used in the experimental design for investigating the influence of liquid PF (LPF) resin viscosity (90, 180, 270 cps), powder PF (PPF) resin particle size in terms of grinding time (0, 15, 30 min), and LPF/PPF combination ratio (25/75, 50/50, 75/25) on strand board performance. Response Surface Analysis suggests a significant quadric model for predicting wet modulus of rupture (MOR) and water absorption (WA) properties. A barely significant linear model was established to predict IB strength. No significant models could be established for dry MOR, dry modulus of elasticity (MOE), MOR retention, and thickness swelling (TS) properties. Response Surface Optimization suggests that the optimal IB, wet MOR, and WA would be 0.59 MPa, 16.9 MPa, and 33.0%, respectively, with 270 cps, 30 minutes, and 25/75 for the optimal resin viscosity, powder grinding time, and LPF/PPF ratio. Resin viscosity, powder grinding time, and LPF/PPF ratio do not significantly influence dry MOR, dry MOE, MOR retention, and TS properties. This study also implies that reducing powder particle size can improve resin efficiency in terms of increased resin coverage and uniform distribution.
Product quality control is performed by a majority of sawmills, but to varying degrees of intensity. It is more often done at the end of the process, generally in the planing mill once the products are ready for shipping. It is rarely based on standardized statistical quality control procedures specific to key sawmill processing stations. The general objective of this research project is to establish quality control procedures to ensure optimal operating efficiency of sawmill equipment at every major step in the manufacturing process. The results are presented in the form of a series of guidelines for specific procedures at target processing stations. These guidelines are intended for sawmill quality controllers and those in charge of process optimization. They are an excellent source of information for setting up a process control program.
This report addresses the primary breakdown process, and the guidelines cover the following elements:
Equipment fine tuning: this section provides a checklist of essential elements to ensure the equipment is running properly. Special attention is paid to the infeed, scanning and positioning systems on the machine.
Optimization of operations: this part addresses the role of the operator (in manual and optimized systems) and focuses on clarifying optimization parameters, an understanding and mastery of which are crucial to optimal machine operation.
Quality control: this section suggests simplified daily control procedures for critical equipment areas. The goal is to ensure top performance of the primary breakdown line.
Performance: This last section provides a performance evaluation procedure for a primary breakdown line and compares results against industry standards.
Included in the appendices are forms for the various proposed procedures.
L’objectif général de ce projet de recherche est d’établir des procédures de contrôle du procédé visant la production de produits conformes à chaque étape du procédé de transformation à l’aide d’équipements fonctionnant avec une efficacité maximale.
Le présent document est consacré à l’équarrisseuse-déchiqueteuse (équarrisseuse, canter). Le contenu comporte quatre parties : les méthodes de mise au point selon un horaire suggéré, les responsabilités de l’opérateur et la mesure de la productivité, le contrôle de qualité de fabrication du produit, les standards de l’industrie et le calcul des pertes. Des tableaux de compilation de données sont aussi fournis à titre d’exemple.
La particularité des prises de données dans ce document consiste à cocher la valeur ou la caractéristique obtenue dans une carte de contrôle, plutôt que de l’écrire au complet. Cette méthode permet de visualiser graphiquement la performance de l’équipement au cours des dernières heures et des derniers jours en un seul regard. Une action corrective peut alors être prise rapidement ou être planifiée si une caractéristique tend à s’éloigner des critères de performance exigés.
To evaluate the effects of mountain pine beetle-killed (MPB) lodgepole pine on particleboard performance, a series of homogeneous particleboards were manufactured from green and MPB pine particles at five mixing ratios (100:0, 75:25, 50:50, 25:75, 0:100). Particles were characterized for wood chemical properties (pH value and acid buffer capacity) and particle size distribution. Particleboards were evaluated by testing physical and mechanical properties such as internal bond (IB) strength, modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling (TS) and water absorption (WA), and linear expansion (LE).
Green pine and MPB pine showed similar chemical properties (in terms of pH value and acid buffer capacity) and particle size distribution. Based on these wood chemical and physical characteristics, it was expected that the use of MPB pine as substitution of green pine would not likely cause a bonding problem in particleboard manufacturing. Evaluation of board physical and mechanical properties indicates that MPB pine particles could substitute green pine particles up to 100% without a negative impact on board properties such as IB, MOR/MOE, and TS/WA. In fact, these board properties were improved with the addition of MPB pine, especially at 25% and 50% MPB pine particle substitution levels. A negative impact was observed only for LE. An increase in MPB pine in the substitution of fresh pine from 0% to 50% reduced the LE value; however, a further increase, up to 100%, increased the LE value. From this study, it can be concluded that MPB pine can be safely used to substitute fresh pine, at substitution levels from 50% to 75%, in manufacturing particleboard. Particleboard made from MPB lodgepole pine appeared darker in colour as compared with boards made from green lodgepole pine because of the presence of blue stain in the MPB wood.
The feasibility of using mountain pine beetle-killed (MPB) lodgepole pine as raw material for high density fibreboard (HDF) manufacturing was evaluated by making a series of HDF panels from green and MPB pine particles at five mixing ratios (100:0, 75:25, 50:50, 25:75, 0:100). Fibres were characterized for fibre length and width distributions. HDF boards were evaluated by measuring board density profiles and physical and mechanical properties, such as internal bond (IB) strength, modulus of rupture (MOR), modulus of elasticity (MOE), 24-h thickness swelling (TS) and water absorption (WA), 24-h Edge TS, and linear expansion (LE). Test results show that substitution of more than 25% green pine with MPB pine seemed to have a negative impact on board IB strength; however, no adverse impact was observed for other board properties. In general, the use of MPB pine seems to improve board performance, particularly at the 25% substitution level. In addition, the fibres derived from green and MPB pines had similar length and width distributions when both pine chips were refined under the same conditions. This study implies that MPB lodgepole pine is a suitable raw material for HDF manufacturing.
To investigate hardwood species as a substitute for spruce/pine/fir (SPF) softwoods in particleboard manufacturing, a series of three-layer particleboards were prepared from various hardwood species including white birch (WB), sugar maple (SM), and red oak (RO) as well as their mixtures (WB/SM, WB/RO, and SM/RO at mixing ratios of 25/75, 50/50, and 75/25, respectively, and WB/SM/RO at mixing ratios of 25/25/50, 25/50/25, and 50/25/25, respectively). For each single and mixed species, two substitution levels of hardwood species for SPF were evaluated: overall 22% (10% in face and 30% in core) and 40% (10% in face and 60% in core). After conditioning at 65% RH/20oC, all boards were evaluated for mechanical and physical properties including internal bond (IB) strength, modulus of rupture (MOR), modulus of elasticity (MOE), 24-h thickness swelling (TS) and water absorption (WA), and linear expansion (LE).
All panels made from single and mixed hardwood species at 22% and 40% SPF substitution levels, with one exception, met ANSI A208.1 standard requirements for Grade M2 particleboard in terms of IB, MOR, MOE, and LE. The panel made with sugar maple at the 40% substitution level failed to meet the MOR requirement. This failure was attributed to the lower board density or compression ratio.
For the panels made from hardwood species at the 40% SPF substitution level, the average values for IB, MOR, and MOE exceeded the standard requirements by 177%, 21%, and 23%, respectively, while the average LE value was lower than the standard requirement by 30%. These results imply that more hardwoods could be used as substitutes for SPF softwoods in particleboard manufacturing, especially in the core layer.
With respect to overall panel performance, the following hardwood species appeared to produce panels that were comparable to the SPF control: (1) 100% red oak at both substitution levels (22% and 40%); (2) 25/75 WB/SM at the 40% substitution level; (3) 25/75 WB/RO at both substitution levels; and (4) 25/75 and 50/50 SM/RO at the 40% substitution level.
This study shows that wood species and density, original form of raw material, and moisture content (before grinding) influence the particle size distribution, and, consequently, influence the resin efficiency in terms of resin coverage over particle surfaces. This implies that the disadvantage of using hardwoods, in terms of their higher density and lower compression ratio (board density over wood density), as a substitute for SPF softwoods for manufacturing high-quality particleboard could be overcome by improving resin efficiency via optimizing particle size distribution during grinding and screening processes.
The overall objective of this research project was to develop process control procedures to facilitate the generation of products that meet standards at every step of the conversion process, using equipment operating at maximum efficiency.
This report focuses on the ring debarker. It contains four parts: set-up methods using a proposed schedule; operator responsibilities and productivity measurement; quality control in product manufacturing; industry standards and loss calculation. Data compilation tables are also provided as examples.
The distinguishing characteristic of the data collection method used in this document is that it involves checking off values or characteristics on a control chart. This allows users to note equipment performance over a number of hours and days at a glance, and to plan or implement corrective measures, if results deviate too far from targeted performance criteria.
Readers are encouraged to obtain a copy of a special Forintek publication entitled Ring Debarking (SP 525E). Several figures and methods included in this manual are used in the overall process control procedure described in this report.
The objectives of this study were to characterize OSB panel permeability in comparison with plywood and low density fiberboard; to determine the effect of panel characteristics on the speed of moisture movement through the thickness of the OSB panels; to create a finite element model of the permeability of OSB; to suggest improvements of the OSB panel structure in function of permeability.
The introduction of current report presents extracts of the theory of moisture transfer in wood materials and introduces the concept of water potential and the instantaneous profile method as adapted to OSB to be used for the determination of the diffusion coefficient (D).
The experimental part is divided into three stages. In the first stage the permeance of the OSB panels, plywood and low density fiberboard is compared according to the dry cup method. The experiments showed that the low-density fiberboard panels’ permeance is more than twice as high as compared with the permeance of the OSB panel; the Western Red Cedar has an approximately equal permeance with the OSB panel, which is in turn higher as compared with the permeance of the Aspen plywood. The Aspen plywood produced with parallel plies shows approximately 30 % higher permeance as compared to the regular plywood.
In the second stage, the effects of density, strand geometry and orientation level, panel density and moisture content on the permeance and on the diffusion coefficient are determined. The experiment is organized based on an experimental design. For the permeability (permeance and diffusion coefficient), the lower the strand thickness, the lower the permeability; the lower the level of strand orientation, the higher the permeability; the larger the strand width and length (surface area), the lower the permeability, the higher the permeability.
During the third stage, the dynamics of moisture movement in the panel is modeled with a finite element model based on an unsteady-state moisture transfer equation and the results from simulations are compared to experimental results in order to validate the model. Ten cases of adsorption and two cases of desorption are considered. Seven of the cases are duplicated with experimental results to serve for validation of the model. The closeness of the experimental and simulation results allow concluding the validity of the finite element model, which can be used to optimize the OSB panel structure by selecting practical layer characteristics leading to desired moisture permeability.
Preservative treatment to achieve termite and decay resistance has potential to develop new products and markets for post-MPB lumber. The objective of this work was to determine the feasibility of through treating post-MPB lumber to reduce Canada’s competitive disadvantage versus US southern pine and New Zealand radiata pine in markets where termite and decay resistance is important. Post-MPB sapwood has increased permeability but the heartwood is unchanged from its normal low permeability. There is an opportunity to take advantage of the increased permeability of the sapwood in treated lumber with minimal heartwood content. Another potential advantage of treating is the ability to mask bluestain discolouration. Post-MPB lumber was sorted into a heavy stain group (stain across three sides) and a non-sorted group of mixed proportions of heartwood and sapwood. Both non-dried (ND) and kiln-dried (KD) lumber, the latter with planed or combed surface, was pressure treated with borate using a conventional process then stored to allow moisture equilibration. Additional KD lumber was pressure treated with borate at a higher solution temperature and with alkaline copper quaternary (ACQ). Further material, stained and mixed, planed and combed, was treated with a novel accelerated process involving a dip followed by 72 hrs kiln conditioning.
The stained sort, either pressure treated with DOT or with the dip plus 72hr kiln conditioning gave through treatment (over 85% cross section) after one week storage, comparable to requirements for Southern Pine. Lumber sorted for heavily stained sapwood content resulted in about twice the uptake from pressure treatments. ACQ treatment gave substantial penetration only in sapwood, with a very thin shell in the heartwood. A higher temperature DOT solution did not increase uptake from pressure treatment. Pressure treatment uptakes were lower in non-dried wood than in kiln-dried wood. Pressure treatment of kiln-dried lumber with DOT at 20°C met penetration and retention targets only with stained sort combed samples. Pressure treatment of kiln-dried lumber with DOT at 35°C met penetration and retention targets only with stained sort planed (combed not tested) samples. None of the pressure treatments had heartwood penetrations with 80% at or over 10mm even after 2 weeks storage whereas dip-plus-kiln-conditioning treatment met this requirement for mixed sort planed and combed with Treatment 1 and mixed sort combed with Treatment 2 after one week.
Dip-plus-kiln-conditioning uptake was greater on combed surfaces but, strangely, this was not reflected in increased borate loading. Dip-plus-kiln-conditioning Treatment 2 uptakes and retentions were greater than in dip-plus-kiln-conditioning Treatment 1. The dip-plus-kiln-conditioning process increased the wood moisture content to 20% to 30% MC, with the greater increases resulting from dip-plus-kiln-conditioning Treatment 2. Process modifications will be needed to reduce the moisture uptake or bring the moisture content down to below 20% before shipping to prevent problems with stain and mold.
The dip-plus-kiln-conditioning process met penetration and retention targets with stained sort planed or stained sort combed samples treated with dip-plus-kiln-conditioning Treatment 2. Targets were met immediately after treatment. None of the data adequately reflects the difference in uniformity of treatment between the pressure treatment and the dip-plus-kiln-conditioning treatment. Dip-plus-kiln-conditioning treatment gave a much more uniformly penetrated shell around the whole cross section, though this was not reflected in the analyzed heartwood retentions.
Further refinements are needed to the dip-plus-kiln-conditioning process, but these will likely be customized for each sawmill depending on whether spray or dip is used to apply the formulation and the type of kiln used for conditioning. The lack of relationship between analysed retentions, uptakes and penetrations in the dip-plus-kiln-conditioning process requires further investigation.
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.
The performance of machinery is critical to wood products manufacturing. The first step in controlling this performance is selection and purchasing the machine that is most suited to a company's performance requirements. Unfortunately, this is not a straightforward task since very few machine centers sold by competing manufacturers are identical. The second step is to identify the appropriate set-up for the required machining operations. The first goal of this report is to suggest evaluation methods and develop benchmarks in the area of machining for three common machine centers: CNC routers, edgebanders and beam saws. Wood product manufacturers in Saskatchewan identified that these machines are key to their businesses and processes. The second goal is to identify machining parameters for western white birch on CNC routers. The developed machining evaluation method for CNC routers includes examination of the control system and the ability of the router to locate and cut shapes. Machining precision is important because it directly affects part fitment and when errors occur, rejects are created. Four of the six routers produced accurate, precisely located cuts but two machines had problems cutting parallel lines and precise arcs. All of the machines except two had issues with cutting square edges. The developed evaluation method for the edgebanders examines their ability to band melamine coated PB without causing chips to the melamine. Melamine chips are quality problems that can significantly degrade the value of the product. Three of the six machines evaluated had low occurences of melamine chips while two had variable results and the third had significant chips. The developed evaluation method for beam saws examines their ability to cut parts of a precise size with edges that are straight. Imprecise beam saws create waste in the form of rejects and require the over sizing of parts to compensate. Two of the five machines were able to cut precisely sized parts with straight edges ready for use in manufacturing. Two of the beam saws had problems cutting straight edges. The developed machine performance benchmarks include the effect of a wide range of machines factors including age, precision, costs and operator skill. This should allow industry to compare the performance of their machines, as well as future purchases, with others in the industry. the developed guidelines for routing of western white birch also examine a wide range of machining parameters for the common processes of sizing and edging panels. The panel surface quality tends to decrease with increasing bite and is significantly better when downmilling. On CNC routers, these parameters are straightforward to control as long as production goals can be met.