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Development of guidelines for the successful industrial operation of supercritical speed saws. (Final Report)

https://library.fpinnovations.ca/en/permalink/fpipub5521
Author
Lister, P.F.
Hutton, S.G.
Kishimoto, J.K.
Date
May 1996
Edition
37411
Material Type
guide
Research report
Field
Wood Manufacturing & Digitalization
Author
Lister, P.F.
Hutton, S.G.
Kishimoto, J.K.
Contributor
Science Council of British Columbia.
Date
May 1996
Edition
37411
Material Type
guide
Research report
Physical Description
43 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Circular saws
Saw circular
Saws
Series Number
W-1319
Location
Vancouver, British Columbia
Language
English
Abstract
Thin circular saws can suffer from a vibration phenomena called critical speed instability. At the critical speed, a resonant condition occurs where a saw can snake slowly from side-to-side producing unacceptably large sawing variation. To avoid this problem, most circular saws operate at 10 to 15 percent below the first critical speed. Unfortunately, this practice limits reductions in saw plate thickness and corresponding improvements in lumber recovery. Recently, several mills have been able to operate guided splined-arbor saws above critical speed. These supercritical speed saws offer significant sawing performance improvements by allowing both high recovery and high production rates. The use of these saws remains rare, however, and very little knowledge is available to guide mills that want to investigate this promising area. This report describes laboratory tests involving two supercritical speed saw configurations which are operating successfully in industry. Detailed descriptions of these configurations are given and guidelines for use are described. Idling and cutting tests were completed to characterize vibrational behaviour and demonstrate sawing performance levels. Tests were done to investigate the effect of changes in saw tensioning, saw tooth design parameters, saw and feed speeds and saw plate thicknesses. Test results confirm that for the sawing configurations tested, operating speeds can be found in the supercritical speed region where stable idling behaviour allows successful sawing. As with conventional saws, sawing accuracy is best at lower feed speeds. However, by operating at supercritical speeds, acceptable sawing accuracy can be achieved at higher feed speeds than are possible using conventional saws. Saw tensioning allows further increases in saw and feed speeds, but is not essential for supercritical speed operation. Changes in saw thickness strongly affect sawing performance levels and lumber recovery. Thinner saws have higher sawing variation and must operate at lower feed speeds than thicker saws. Curves showing the relationship between saw plate thickness, feed speeds and sawing accuracy are presented which can be used to assess the economic benefits of the supercritical speed saws that were tested. Supercritical speed circular saws offer considerable potential to improve sawing performance and increase lumber recovery. These saws allow reductions in saw kerf widths while maintaining high feed speeds and acceptable sawing accuracy.
Saws - Circular
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Mission to study wood machining technology in Japan : October 1-10, 1995

https://library.fpinnovations.ca/en/permalink/fpipub37391
Author
Lister, P.F.
Date
October 1995
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Lister, P.F.
Date
October 1995
Material Type
Research report
Physical Description
28 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Saw mills
Sawing
Series Number
W-1259
Location
Vancouver, British Columbia
Language
English
Abstract
This paper describes observations made during a trip to Japan to study wood machining technology. Topics include highlights of the 12th International Wood Machining Seminar, the 32nd Nagoya International Woodworking Machinery Fair and several visits to Japanese companies. Wood machining technology in Japan (WP-OI 95.11) Copies available from Pacific Forest Centre, Canadian Forest Service, 506 West Burnside Road, Victoria, B.C. V8Z 1M5. Fax 604 363-0797.
Sawmills - Symposium - Japan
Cutting - Symposium - Japan
Sawing - Symposium - Japan
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Resultats de l'enquete sur la performance du sciage dans les scieries canadiennes de bois resineux

https://library.fpinnovations.ca/en/permalink/fpipub4985
Author
Lister, P.F.
Date
January 1997
Edition
41819
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Lister, P.F.
Date
January 1997
Edition
41819
Material Type
Research report
Physical Description
37 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Surveys
Softwoods
Saw mills
Sawing
Performance
Canada
Series Number
Service canadien des forets no. 46
E-3064
Location
Sainte-Foy, Québec
Language
French
Abstract
Sawmills - Canada - Survey
Sawing performance
Softwoods
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Results from a test of bevelled tooth bandsaw blades

https://library.fpinnovations.ca/en/permalink/fpipub5515
Author
Lister, P.F.
Sykes, D.
Date
October 1995
Edition
37390
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Lister, P.F.
Sykes, D.
Date
October 1995
Edition
37390
Material Type
Research report
Physical Description
8 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Saw tooth
Band saws
Saw bands
Saws
Bands
Blades
Sawing
Design
Series Number
W-1256
Location
Vancouver, British Columbia
Language
English
Abstract
This report describes the results of a mill test investigating the effect of a 15 degree alternate top bevel (ATB) tooth for bandsaws. The test involved comparing the sawing variation and surface roughness of Douglas-fir lumber cut by both ATB and standard saws. The test results showed no improvement in sawing accuracy with the ATB blades. In fact, as the blades became dull, the sawing accuracy of the ATB saws deteriorated faster than for the standard blades. Visual evaluation of surface roughness also indicated that the ATB saws produce slightly rougher lumber. However, this may be due to increased tooth bite associated with the ATB teeth. Further testing will be required to determine if the results of this test are truly representative of the performance of ATB bandsaws in general.
Saws - Band
Sawing - Blades
Saws - Tooth design
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Results of sawing performance survey in Canadian softwood sawmills

https://library.fpinnovations.ca/en/permalink/fpipub997
Author
Lister, P.F.
Date
March 1995
Edition
37374
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Lister, P.F.
Contributor
Canada. Canadian Forest Service.
Date
March 1995
Edition
37374
Material Type
Research report
Physical Description
32 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Saws
Circular saws
Band saws
Saw circular
Saw bands
Bands
Saw mills
Efficiency
Kerf
Sawing
Recovery
Quality control
Qualitative analysis
Series Number
W-1198
Location
Vancouver, British Columbia
Language
English
Abstract
To document the current state of sawing performance in Canadian sawmills, a survey was carried out in 47 mills located in the major lumber producing regions of Canada: B.C., Alberta and Quebec. The survey was restricted to sawmills producing softwood lumber products, and to band and circular saws used for primary and secondary breakdown. Data characterizing sawing performance, as well as detailed information on saw and machinery specifications, were collected during visits to each participating sawmill. The results of the survey are presented in this report. Detailed specifications are given for band and circular saws, and sawing performance levels are discussed. The results of the survey show that considerable opportunities exist for improving the performance of both band and circular saws. The large range in saw kerf widths identified in the survey indicate that lumber recovery could be significantly improved by reducing kerf to the levels of the best machines. The performance of these machines demonstrates that thin kerf widths can be achieved while high production rates and small sawing variation are maintained. Specifications for the thinnest kerf machines are presented in the report and opportunities for improving sawing performance levels are also discussed. This report will interest sawmill managers, sawfilers and other mill personnel who want to know how the sawing performance of their mill compares to that in similar mills included in the survey.
Sawmilling - Efficiency
Sawing - Quality control
Sawing - Thin kerf
Recovery
Saws - Band
Saws - Circular
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