Thirty full-length sample trees from the B.C. Interior were selected for a study to determine whether external log characteristics can predict internal log quality. The sample trees were also used to create 3-dimensional log images for sawmill simulation purposes. "LogSaw", a simulation tool with internal log defect detection capabilities, was used to explore the extent to which internal and external log quality information can improve log breakdown optimization. A model of a hypothetical sawmill producing lumber for the standard North American dimension market was created to study how lumber value recovery depends on different sawing optimization scenarios.
Three sawing optimization scenarios using different levels of knowledge of internal log defects were compared to currently used sawing optimization technique:
Ideal sawing optimization - all defects within log interior are known.
Sawing optimization using only the knowledge of surface knots.
Sawing optimization using log rotation instructions based on zones of least external knot density.
Simulation results have shown that it is worthwhile to “look into the log”. When compared with the current optimization technique, the sawing optimization, including the full knowledge of log interior, has increased the value recovery by 6.2%. When only the surface knots were projected into the log interior and included in the optimization, the value recovery had increased by 4.3%. Even this 4.3% increase is still a big improvement because this sawing optimization could be implemented using currently available scanning technologies and optimization software enhanced to include log surface knots. The scenario of using log rotation instructions based on predicted zones of least internal knot density did not show value recovery improvement.
Including surface knots in the log breakdown optimization has considerably increased sawmill revenue; the hypothetical sawmill considered in this study, processing 400,000 m3 of log per year, has increased its revenue by $2.2 million.
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.
A mill test and a study were carried out to provide a benchmark as to what is the best debarker performance achievable on frozen wood with properly adjusted debarker settings and well-maintained equipment. The test results have shown that:
The fibre to bark ratio decreased to 12.7% from the 20.9% observed in a previous Forintek study of sawmills with average debarker performance.
The lumber value recovered from logs was 10.7% higher than that achieved with average debarking, and the corresponding lumber volume increase was 10.4%.
The debarker removed 97.3% of the bark volume.
The fibre loss was 1.2% .
For a sawmill processing 100,000 m3 of logs during a winter period of three months, losses attributed to poorly operated debarkers can amount to as much as $1.4 million.
Computer simulation was used to evaluate the performance of three scenarios of sawmill operation: 1) External Scanning at the bucking station, 2) X-ray Scanning with external plus partial internal knot scanning at the bucking station and 3) Perfect Scanning with external plus full internal knot scanning throughout the mill.
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 comparison of the performance of the three operational scenarios.
The X-ray Scanner Scenario provided a 2% value recovery increase compared to that of External Scanner Scenario. The Perfect Scanner Scenario added an additional 5.5% to that of X-ray Scanner Scenario. This was due partly to improved scanning at the bucking station but more so to the internal defect detection at all machine centers in the mill.
Conclusions of the study should help sawmillers in their investment decisions regarding sawing optimization improvements.
This is the first publication from a project to quantify the opportunity to use technology to increase value recovery from the MPB killed timber resource. Baseline simulation studies using a hypothetical BC interior sawmill layout will be used to estimate lumber value loss as a function of degree of defects in beetle killed timber. Additional simulation studies will explore the potential to accelerate value recovery using emerging technologies.
This report summarizes the results of a Forintek survey of equipment suppliers currently developing technologies to increase lumber value recovery. The survey was completed in February 2005. The results will be used to design the simulation studies to be performed in 2005/06. The results are based on private discussions, visits to laboratories and a questionnaire (see Appendix) emailed to companies developing machine vision system and/or optimization software.
Emerging technologies that will help the sawmill industry to lessen the damage caused by the MPB include: 1) machine vision systems for detecting bluestain and radial-checks and, 2) optimization software capable of incorporating defect information in the breakdown solution. Depending on existing sawmill equipment and machinery, the cost of systems that include machine vision and log breakdown optimization that can interpret defect information, is in the range of $65,000-$200,000. Unfortunately, there is no information available on the increase in lumber value recovery that can be obtained with these technologies and investment decisions are difficult. What is more, there is a lack of consensus within the sawmill industry on the usefulness of these systems. There are sawmillers who doubt that these machine vision systems would consistently outperform manual operation and add enough value to justify the cost. Thus, the primary study, quantifying the benefit of reducing the negative impact of the MPB defects, of which this report is a part, will provide useful information for sawmillers for return-on-investment calculations.
Optimization programs, full-profile scanning, and powerful computers used with auto-rotation systems make thorough log rotation, log positioning and sawing decisions possible. However, high log throughput, bumpy log surfaces, and heavy sawlogs make accurate mechanical execution difficult. How accurately can auto-rotation systems execute thorough log rotation and log positioning decisions? Two mill tests were carried out to estimate rotation errors and unintentional log movement. OPTITEK®, Forintek's log breakdown simulator, was used to analyse the effect positioning errors have on the economic benefits of auto-rotation systems.
As part of the Workforce and Communities Program of Forest Renewal BC, Forintek Canada Corp. (Forintek) and the Forest Engineering Research Institute of Canada (FERIC) collaborated on a study to determine if changes to current harvesting and manufacturing methods could improve the utilization of decadent stands of western hemlock (Tsuga heterophylla (Raf. Sarg.)) and amabilis fir (Abies amabilis Dougl. ex Loud) in the Prince Rupert forest region of British Columbia. FERIC documented present logging methods, and used a computer module ATLAS to determine how different approaches to harvest planning could reduce delivered wood costs. Forintek used an internal log defect sawing simulation model, "Log Saw", to determine how changes in sawing strategies and product categories could improve mill revenue. The results of these two studies are provided here as two separate reports. It is recommended that these models serve as the focus for additional research required to complete an assessment of the full utilization potential of the resource.
This project focuses on the affect of errors that exist in log rotation systems for optimized double length infeed (DLI) log breakdown lines common to the sawmills in North America. The potential value recovery increase that could be achieved by adjusting log turner optimizer settings and/or PLC programming, to match the actual machine centre log rotation capability, is estimated. The potential of the newest commercially available log rotation systems to improve accuracy of log rotation and thus, increase product value recovery are also estimated.
Using both analytical and experimental data, the loss in lumber value that can occurr due to errors between the desired opitmized log rotation angle and the actual rotation angle are simulated. Five log rotation systems are investigated from the theoretical “perfect” system with accurate settings and no errors down to older, poorly maintained, systems with incorrect settings and large errors in rotation performance.
The work done here provides new knowledge about the importance of using accurate values of log turner settings and/or making suitable adjustments of the log turner PLC, to select best rotation angle and minimize rotation errors. The increase in value recovery and ROI that may be achieved in a particular mill will depend on the magnitude of differences between the current values of log turner settings and their correct values and/or the quality of the adjustments of the log turner PLC. The results presented here show that in typical sawmills the optimal adjustment to log turner settings and/or PLC may increase value recovery in 0.5% - 1.5% range and a ROI over 1,250%, using $20,000 cost of determining the adjustment. Replacing older, worn out, log turning systems with the newest conventional systems may increase value recovery in 0.5% - 1.2% range and ROI in 80% - 190% range. Replacing conventional log turning systems with the newest systems utilizing advanced technologies may increase value recovery in 1.2% - 2.4% range and ROI in 100% - 240% range.
The appendendices mentioned in the report are found at this link: