Improved spreadsheet software capabilities have brought optimization to users with little or no b... more Improved spreadsheet software capabilities have brought optimization to users with little or no background in mathematical programming. Better interface capabilities of spreadaheet models now make it possible to combine optimization models with a spreadsheet system. Sawmill production and inventory systems posseses many features that make them suitable application environment for spreadsheet optimization. This paper describes a spreadsheet model that optimizes log allocation and lumber production.
A log inventory model and a real-time hardwood process simulation model were developed and combin... more A log inventory model and a real-time hardwood process simulation model were developed and combined into an integrated production planning and control system for hardwood sawmills. The log inventory model was designed to monitor and periodically update the status of the logs in the log yard. The process simulation model was designed to estimate various sawmill performance parameters taking into account the different static and dynamic features of a sawmill. Besides the log inventory and simulation models, the system also has a front-end spreadsheet-based optimizer for determining optimal log input mix. Thus, the integrated system has the capability to determine the optimal lumber production schedule (including log input mix) which is also operationally feasible on real-time.
Published literature contains a number of optimization and simulation models dealing with the pri... more Published literature contains a number of optimization and simulation models dealing with the primary processing of hardwood and softwood logs. Simulation models have been developed primarily as descriptive models for characterizing the general operations and performance of a sawmill. Optimization models, on the other hand, were developed mainly as analytical tools for prescribing optimal production plans but with minimal concern on real-time day-to-day operations of a sawmill. This paper describes a combined simulation and optimization model that considers both the determination and the implementation of optimal production schedules. Emphasis centers on the performance and utilization of various machine centers, including production delays, buffer decks, queue capacities, operating time, and equipment and resource utilization.
For the last few years the authors as part of the Center for Automated Processing of Hardwood hav... more For the last few years the authors as part of the Center for Automated Processing of Hardwood have been attempting to develop a multiple sensor hardwood defect detection system. This development activity has been ongoing for approximately 6 years, a very long time in the commercial development world. This paper will report the progress that has been made and will delineate the reasons the effort has taken so long to reach this point in the development effort.
In a recent edging and trimming study at three hardwood sawmills, it was observed that the lumber... more In a recent edging and trimming study at three hardwood sawmills, it was observed that the lumber volume produced was approximately 10 percent less than would be necessary to make the most valuable lumber. Furthermore, the excess portion of wood that was removed from the edging and trimming process contained a large percentage of clearwood. In light of rising costs and increasing environmental concerns, the option of producing furniture parts from unedged and untrimmed boards is explored. This research investigates the potential furniture part yields from unedged and untrimmed boards compared to both optimal and actual edging and trimming practices. The resulting volume of cuttings from unedged and untrimmed boards was found to be 25 percent higher than from the actual edged and trimmed lumber produced at the mills. Also, the volume of long cuttings (84 in.) was found to be 22 percent higher from the unedged and untrimmed boards. In addition to more efficiently utilizing our timber resources, the overall cost of furniture cuttings from unedged and untrimmed boards was found to be 8 percent less even when considering the additional costs of drying, handling, and processing.
This study determined the influence of product and supplier attributes on hardwood lumber purchas... more This study determined the influence of product and supplier attributes on hardwood lumber purchases by wood furniture manufacturers and investigated differences across manufacturer type, geographic region, firm size, and kiln ownership. Professional lumber buyers rated the importance and difference across suppliers of various attributes. Purchase influence scores were calculated for each attribute based on importance and difference ratings. MANOVA, Tukey's tests, and Bonferroni t-tests detected if differences existed between purchase influence scores across manufacturer type, geographic region, firm size or kiln ownership. Load-to-bad Consistency, Accurate Grading, No Warp, Crook and Bow, Accurate Moisture Content, and Quote Competitive Price were the attributes that most influenced the purchase decisions of respondents. No differences were detected between purchase influence scores across geographic regions. However, differences were detected based on furniture manufacturer type, firm size, and kiln ownership. Manufacturers of wood office and wood household furniture were more influenced by appearance attributes (No Stain, No Surface Checks, and No Chipped Grain) than were upholstered furniture manufacturers. Larger firms' purchases were more influenced by attributes related to production scheduling and efficiency (Correct Tally, Desirable Width Mix, Stacking of
Considerable volumes of solid hardwoods, solid softwoods, and wood panels are used to manufacture... more Considerable volumes of solid hardwoods, solid softwoods, and wood panels are used to manufacture pallets and containers in the United States. Increasing quantities of these materials are recovered from the waste stream for reuse and recycling. Two important groups involved in this recovery and recycling are firms in the pallet industry (SIC 2448) and landfill operations (municipal solid waste landfills and construction and demolition waste landfills). Firms in the pallet industry received an estimated 83.3 million pallets for recycling in 1993. Municipal solid waste landfills processed approximately 880 thousand tons of pallets in 1995. At construction and demolition waste landfills, approximately 162 thousand tons of pallets were processed. Ground pallet material is used to produce mulch, bedding, compost, soil amendments, and fuel. Products with building and construction applications include particleboard, fiberboard, cement board, insulation board, and wood-plastic composites. Strip flooring holds perhaps the greatest potential as a high value-added product from pallet wood.
An estimated 4.53 billion board feet of solid hardwood and 1.79 billion board feet of solid softw... more An estimated 4.53 billion board feet of solid hardwood and 1.79 billion board feet of solid softwood were used in the production of pallets and containers in 1995. When compared to estimates for 1992, the use of both softwoods and
This paper describes an automatic color sorting system for red oak edge-glued panel parts. The co... more This paper describes an automatic color sorting system for red oak edge-glued panel parts. The color sorting system simultaneously examines both faces of a panel part and then determines which face has the "best" color, and sorts the part into one of a number of color classes at plant production speeds. Initial test results show that the system generated over 91 percent acceptable panels from automatically sorted red oak panel parts, which exceeded target plant production goals. The color sorting system was developed in cooperation with NOVA Technologies and is now commercially available under the name of CESYS by Group Seven Systems.
With rising timber costs and a decreasing supply of high-grade timber resources, manufacturers of... more With rising timber costs and a decreasing supply of high-grade timber resources, manufacturers of solid wood products need to adopt more efficient processing methods that better utilize existing timber resources. To address this need, this study explores the potential of converting hardwood logs directly into dimension parts. The specific objective of this study was to estimate the potential cutting yield of dimension parts and potential value recovery obtainable from Factory Grade 2 and 3 red oak sawlogs under various processing configurations and cutting bills. A combination method of sawing logs into flitches and then cutting flitches into dimension parts was used. Two log sawing patterns (live sawing and five-part sawing) combined with two cutting sequences (rip first and crosscut first) and three cutting bills were tested. The results indicated that Grade 2 logs produced higher dimension yield than Grade 3 logs. However, Grade 2 logs resulted in much less value recovery per dollar log input than Grade 3 logs because of the notably higher price of Grade 2 logs. These results suggest that direct processing systems offer a very promising method for converting low-grade timber resources into high-value solid wood products. Other results of the study show how different processing configurations and cutting orders can affect yield and value recovery.
Estimates of the use of new and recycled wood materials by the U.S. pallet industry are presented... more Estimates of the use of new and recycled wood materials by the U.S. pallet industry are presented. The industry (including SICs 2441, 2448, 2449) consumed 4.74 billion board feet of solid hardwoods and 2.15 billion board feet of solid softwoods in 1992. The most common individual hardwood species were oak and yellow-poplar. Douglas-fir and southern yellow pine were the most commonly used softwoods. Approximately 65.8 million pallets (containing an estimated 1.03 billion board feet) were received for recycling in 1992 by firms included in SIC 2448. Of this total, 912 million board feet were used again in a pallet. The unlagged industry recycling rate for pallets was estimated at 13 percent in 1992 and 16 percent in 1993.
Because of rising timber costs and an increasing demand for high-grade timber, suppliers of solid... more Because of rising timber costs and an increasing demand for high-grade timber, suppliers of solid wood products need additional material options. We feel that European and Japanese processing concepts of producing green dimension and other clear material directly from logs could provide an answer. In this paper we present a brief overview of our research results on producing green dimension from logs. We include yield results, mill designs, and a look at the economics.
This paper describes an automatic color and grain sorting system for wood edge-glued panel parts.... more This paper describes an automatic color and grain sorting system for wood edge-glued panel parts. The color sorting system simultaneously examines both faces of a panel part and then determines which face has the "best" color, and sorts the part into one of a number of color classes at plant production speeds. In-plant test results show that the system generated over 91 percent acceptable panels from automatically sorted red oak panel parts, which exceeded target plant production goals. The technology is also capable of grain sorting panel parts. While sorting parts by grain appears promising in laboratory testing, the grain sorting performance of the technology has not yet been tested in an actual production environment. The color sorting system is a patented technology
Scanning of unplaned, green hardwood lumber has received relatively little attention in the resea... more Scanning of unplaned, green hardwood lumber has received relatively little attention in the research community. This has been due in part to the difficulty of clearly imaging fresh-cut boards whose fibrous surfaces mask many wood features. Nevertheless, it is important to improve lumber processing early in the manufacturing stream because much wood material is needlessly edged and trimmed away each day. This paper describes a prototype system that scans rough, green lumber and automatically generates a board profile and recognizes important lumber-degrading defects. This portion of the overall "improved edging and trimming project" is primarily concerned with image acquisition and analysis. Commercially available laser sources and a video camera obtain thickness and reflectance information at 1/16-inch resolution. The resulting images are analyzed in order to detect wane and surface defects. Unlike most board-scanning systems, which process planed wood, this system has been designed specifically for use with unplaned boards in the green state. This presents both advantages and challenges in the development of image-analysis algorithms. The current system is described and some preliminary tests specimens are exampled. A demonstration prototype has been completed and will-be part of upcoming workshops at the Wood Education and Resource Center in Princeton, West Virginia.
This paper describes a prototype scanning system that is being developed for the processing of ro... more This paper describes a prototype scanning system that is being developed for the processing of rough hardwood lumber. The overall goal of the system is to automate the selection of cutting positions for the edges and ends of rough, green lumber. Such edge and trim cuts are typically performed at sawmills in an effort to increase board value prior to sale, and this depends on a balance between large board size and the removal of undesirable wood characteristics, such as wane and surface defects. This paper is primarily concerned with image acquisition and analysis. Offthe-shelf hardware components are used with in-house developed software to capture images of a board as it moves longitudinally on a conveyor. Unlike most board-scanning systems, the system described here analyzes rough (unplaned) boards. There are some advantages to this approach, such as increased image contrast due to surface moisture. There are also disadvantages, however, resulting from the appearance of the wood in its unplaned state, which pose new challenges in the development of image-analysis algorithms.
Improved spreadsheet software capabilities have brought optimization to users with little or no b... more Improved spreadsheet software capabilities have brought optimization to users with little or no background in mathematical programming. Better interface capabilities of spreadaheet models now make it possible to combine optimization models with a spreadsheet system. Sawmill production and inventory systems posseses many features that make them suitable application environment for spreadsheet optimization. This paper describes a spreadsheet model that optimizes log allocation and lumber production.
A log inventory model and a real-time hardwood process simulation model were developed and combin... more A log inventory model and a real-time hardwood process simulation model were developed and combined into an integrated production planning and control system for hardwood sawmills. The log inventory model was designed to monitor and periodically update the status of the logs in the log yard. The process simulation model was designed to estimate various sawmill performance parameters taking into account the different static and dynamic features of a sawmill. Besides the log inventory and simulation models, the system also has a front-end spreadsheet-based optimizer for determining optimal log input mix. Thus, the integrated system has the capability to determine the optimal lumber production schedule (including log input mix) which is also operationally feasible on real-time.
Published literature contains a number of optimization and simulation models dealing with the pri... more Published literature contains a number of optimization and simulation models dealing with the primary processing of hardwood and softwood logs. Simulation models have been developed primarily as descriptive models for characterizing the general operations and performance of a sawmill. Optimization models, on the other hand, were developed mainly as analytical tools for prescribing optimal production plans but with minimal concern on real-time day-to-day operations of a sawmill. This paper describes a combined simulation and optimization model that considers both the determination and the implementation of optimal production schedules. Emphasis centers on the performance and utilization of various machine centers, including production delays, buffer decks, queue capacities, operating time, and equipment and resource utilization.
For the last few years the authors as part of the Center for Automated Processing of Hardwood hav... more For the last few years the authors as part of the Center for Automated Processing of Hardwood have been attempting to develop a multiple sensor hardwood defect detection system. This development activity has been ongoing for approximately 6 years, a very long time in the commercial development world. This paper will report the progress that has been made and will delineate the reasons the effort has taken so long to reach this point in the development effort.
In a recent edging and trimming study at three hardwood sawmills, it was observed that the lumber... more In a recent edging and trimming study at three hardwood sawmills, it was observed that the lumber volume produced was approximately 10 percent less than would be necessary to make the most valuable lumber. Furthermore, the excess portion of wood that was removed from the edging and trimming process contained a large percentage of clearwood. In light of rising costs and increasing environmental concerns, the option of producing furniture parts from unedged and untrimmed boards is explored. This research investigates the potential furniture part yields from unedged and untrimmed boards compared to both optimal and actual edging and trimming practices. The resulting volume of cuttings from unedged and untrimmed boards was found to be 25 percent higher than from the actual edged and trimmed lumber produced at the mills. Also, the volume of long cuttings (84 in.) was found to be 22 percent higher from the unedged and untrimmed boards. In addition to more efficiently utilizing our timber resources, the overall cost of furniture cuttings from unedged and untrimmed boards was found to be 8 percent less even when considering the additional costs of drying, handling, and processing.
This study determined the influence of product and supplier attributes on hardwood lumber purchas... more This study determined the influence of product and supplier attributes on hardwood lumber purchases by wood furniture manufacturers and investigated differences across manufacturer type, geographic region, firm size, and kiln ownership. Professional lumber buyers rated the importance and difference across suppliers of various attributes. Purchase influence scores were calculated for each attribute based on importance and difference ratings. MANOVA, Tukey's tests, and Bonferroni t-tests detected if differences existed between purchase influence scores across manufacturer type, geographic region, firm size or kiln ownership. Load-to-bad Consistency, Accurate Grading, No Warp, Crook and Bow, Accurate Moisture Content, and Quote Competitive Price were the attributes that most influenced the purchase decisions of respondents. No differences were detected between purchase influence scores across geographic regions. However, differences were detected based on furniture manufacturer type, firm size, and kiln ownership. Manufacturers of wood office and wood household furniture were more influenced by appearance attributes (No Stain, No Surface Checks, and No Chipped Grain) than were upholstered furniture manufacturers. Larger firms' purchases were more influenced by attributes related to production scheduling and efficiency (Correct Tally, Desirable Width Mix, Stacking of
Considerable volumes of solid hardwoods, solid softwoods, and wood panels are used to manufacture... more Considerable volumes of solid hardwoods, solid softwoods, and wood panels are used to manufacture pallets and containers in the United States. Increasing quantities of these materials are recovered from the waste stream for reuse and recycling. Two important groups involved in this recovery and recycling are firms in the pallet industry (SIC 2448) and landfill operations (municipal solid waste landfills and construction and demolition waste landfills). Firms in the pallet industry received an estimated 83.3 million pallets for recycling in 1993. Municipal solid waste landfills processed approximately 880 thousand tons of pallets in 1995. At construction and demolition waste landfills, approximately 162 thousand tons of pallets were processed. Ground pallet material is used to produce mulch, bedding, compost, soil amendments, and fuel. Products with building and construction applications include particleboard, fiberboard, cement board, insulation board, and wood-plastic composites. Strip flooring holds perhaps the greatest potential as a high value-added product from pallet wood.
An estimated 4.53 billion board feet of solid hardwood and 1.79 billion board feet of solid softw... more An estimated 4.53 billion board feet of solid hardwood and 1.79 billion board feet of solid softwood were used in the production of pallets and containers in 1995. When compared to estimates for 1992, the use of both softwoods and
This paper describes an automatic color sorting system for red oak edge-glued panel parts. The co... more This paper describes an automatic color sorting system for red oak edge-glued panel parts. The color sorting system simultaneously examines both faces of a panel part and then determines which face has the "best" color, and sorts the part into one of a number of color classes at plant production speeds. Initial test results show that the system generated over 91 percent acceptable panels from automatically sorted red oak panel parts, which exceeded target plant production goals. The color sorting system was developed in cooperation with NOVA Technologies and is now commercially available under the name of CESYS by Group Seven Systems.
With rising timber costs and a decreasing supply of high-grade timber resources, manufacturers of... more With rising timber costs and a decreasing supply of high-grade timber resources, manufacturers of solid wood products need to adopt more efficient processing methods that better utilize existing timber resources. To address this need, this study explores the potential of converting hardwood logs directly into dimension parts. The specific objective of this study was to estimate the potential cutting yield of dimension parts and potential value recovery obtainable from Factory Grade 2 and 3 red oak sawlogs under various processing configurations and cutting bills. A combination method of sawing logs into flitches and then cutting flitches into dimension parts was used. Two log sawing patterns (live sawing and five-part sawing) combined with two cutting sequences (rip first and crosscut first) and three cutting bills were tested. The results indicated that Grade 2 logs produced higher dimension yield than Grade 3 logs. However, Grade 2 logs resulted in much less value recovery per dollar log input than Grade 3 logs because of the notably higher price of Grade 2 logs. These results suggest that direct processing systems offer a very promising method for converting low-grade timber resources into high-value solid wood products. Other results of the study show how different processing configurations and cutting orders can affect yield and value recovery.
Estimates of the use of new and recycled wood materials by the U.S. pallet industry are presented... more Estimates of the use of new and recycled wood materials by the U.S. pallet industry are presented. The industry (including SICs 2441, 2448, 2449) consumed 4.74 billion board feet of solid hardwoods and 2.15 billion board feet of solid softwoods in 1992. The most common individual hardwood species were oak and yellow-poplar. Douglas-fir and southern yellow pine were the most commonly used softwoods. Approximately 65.8 million pallets (containing an estimated 1.03 billion board feet) were received for recycling in 1992 by firms included in SIC 2448. Of this total, 912 million board feet were used again in a pallet. The unlagged industry recycling rate for pallets was estimated at 13 percent in 1992 and 16 percent in 1993.
Because of rising timber costs and an increasing demand for high-grade timber, suppliers of solid... more Because of rising timber costs and an increasing demand for high-grade timber, suppliers of solid wood products need additional material options. We feel that European and Japanese processing concepts of producing green dimension and other clear material directly from logs could provide an answer. In this paper we present a brief overview of our research results on producing green dimension from logs. We include yield results, mill designs, and a look at the economics.
This paper describes an automatic color and grain sorting system for wood edge-glued panel parts.... more This paper describes an automatic color and grain sorting system for wood edge-glued panel parts. The color sorting system simultaneously examines both faces of a panel part and then determines which face has the "best" color, and sorts the part into one of a number of color classes at plant production speeds. In-plant test results show that the system generated over 91 percent acceptable panels from automatically sorted red oak panel parts, which exceeded target plant production goals. The technology is also capable of grain sorting panel parts. While sorting parts by grain appears promising in laboratory testing, the grain sorting performance of the technology has not yet been tested in an actual production environment. The color sorting system is a patented technology
Scanning of unplaned, green hardwood lumber has received relatively little attention in the resea... more Scanning of unplaned, green hardwood lumber has received relatively little attention in the research community. This has been due in part to the difficulty of clearly imaging fresh-cut boards whose fibrous surfaces mask many wood features. Nevertheless, it is important to improve lumber processing early in the manufacturing stream because much wood material is needlessly edged and trimmed away each day. This paper describes a prototype system that scans rough, green lumber and automatically generates a board profile and recognizes important lumber-degrading defects. This portion of the overall "improved edging and trimming project" is primarily concerned with image acquisition and analysis. Commercially available laser sources and a video camera obtain thickness and reflectance information at 1/16-inch resolution. The resulting images are analyzed in order to detect wane and surface defects. Unlike most board-scanning systems, which process planed wood, this system has been designed specifically for use with unplaned boards in the green state. This presents both advantages and challenges in the development of image-analysis algorithms. The current system is described and some preliminary tests specimens are exampled. A demonstration prototype has been completed and will-be part of upcoming workshops at the Wood Education and Resource Center in Princeton, West Virginia.
This paper describes a prototype scanning system that is being developed for the processing of ro... more This paper describes a prototype scanning system that is being developed for the processing of rough hardwood lumber. The overall goal of the system is to automate the selection of cutting positions for the edges and ends of rough, green lumber. Such edge and trim cuts are typically performed at sawmills in an effort to increase board value prior to sale, and this depends on a balance between large board size and the removal of undesirable wood characteristics, such as wane and surface defects. This paper is primarily concerned with image acquisition and analysis. Offthe-shelf hardware components are used with in-house developed software to capture images of a board as it moves longitudinally on a conveyor. Unlike most board-scanning systems, the system described here analyzes rough (unplaned) boards. There are some advantages to this approach, such as increased image contrast due to surface moisture. There are also disadvantages, however, resulting from the appearance of the wood in its unplaned state, which pose new challenges in the development of image-analysis algorithms.
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Papers by Philip Araman