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Diagnostic system for backup rolls

https://library.fpinnovations.ca/en/permalink/fpipub5604
Author
Dai, Chunping
Thomas, T.
Date
August 2005
Edition
37765
Material Type
Research report
Field
Wood Manufacturing & Digitalization
, particularly spin-out rate and veneer thickness variation. The best results seemed to come from
Author
Dai, Chunping
Thomas, T.
Date
August 2005
Edition
37765
Material Type
Research report
Physical Description
25 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer cutting
Veneer
Process control
Series Number
General Revenue Report Project No. 3974
W-2219
Location
Vancouver, British Columbia
Language
English
Abstract
A lathe monitoring system has been developed and successfully tried in a mill. The system can measure the position, the hydraulic driving pressure and contact pressure of the backup rolls, the position and the hydraulic driving pressure of the roller bar, the position and contact pressure of the knife carriage against the peeler block and the driving torque of the spindle motor. Some of the monitored data points required additional sensors which were then connected to and then downloaded directly from the lathe controller, i.e., PLC and VME. The results showed that the lathe parameters vary significantly with time and knife position. The backup roll offsets control the lathe performance and peeling quality, particularly spin-out rate and veneer thickness variation. The best results seemed to come from the combination of tighter outer offset and looser inner offset. Further work is needed to fine tune the software program for user-friendly data analyses. More mill tests are required to understand the interactions between the backup rolls, the roller bar, the knife and the block.
Lathes
Process control
Veneers - Cutting, Rotary
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Establishing the optimum panel densification for performance plywood/LVL products - new method developed to measure veneer quality and bondability. Final Report 2004/05

https://library.fpinnovations.ca/en/permalink/fpipub37729
Author
Wang, Brad J.
Date
April 2005
Material Type
Research report
Field
Wood Manufacturing & Digitalization
to Measure Veneer Quality and Bondability by Brad Wang Composites Research Scientist
Author
Wang, Brad J.
Date
April 2005
Material Type
Research report
Physical Description
36 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer
Testing
Mechanical properties
Physical properties
Plywood
Laminate product
Grading
Automatic control
Series Number
General Revenue Report Project No. 3901;3901
W-2158
Location
Vancouver, British Columbia
Language
English
Abstract
In this study, extensive veneer compression tests were conducted to examine the transverse compression behaviour of veneer at both ambient and controlled temperature and moisture content (MC) environments. Based on the results, a novel method was developed to characterize overall surface quality of veneer and other wood materials in terms of their bondability and compression behaviour. The method would have significant implication in both theory and practice. In theory, the general wood compression theory would need to be modified. The revised wood compression theory would include four stages instead of commonly defined three. The first stage, which has long and so far been overlooked but is critically important, could be named as “non-linear conformation”. During this stage, the contact area increases nonlinearly with the load applied. It is this stage that directly reveals the interfacial bonding behaviour of wood materials such as veneer-to-veneer and strand-to-strand and their minimum compression required for achieving adequate contact (bonding). In practice, the method provides a fast and objective way of evaluating surface roughness/quality of veneer and other wood materials. The new method also establishes the maximum compression allowable for achieving the best panel performance in terms of bonding strength, stiffness and dimensional stability. Based on the concept of this method, it was further found that both minimum compression required and maximum compression allowable are independent of temperature and MC, which provides a direct benchmark to the material recovery during panel hot-pressing. In a case study with Trembling aspen veneer, the variation of veneer surface roughness/quality and its effect on resulting material recovery were first revealed. Then, the optimum panel densification was identified for performance plywood and LVL products based on the frequency distribution of the minimum compression required and the maximum compression allowable. Finally, an overall veneer quality index was established to compare veneer overall quality for different species/thickness. The method shows good potential in practical applications for increased material recovery, reduced glue consumption and improved panel performance.
Veneers - Strength - Tests
Plywood - Strength - Tests
Lumber, Laminated veneer - Strength - Tests
Grading - Automation
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Improved green veneer clipping and moisture sorting. Final Report 2004/05

https://library.fpinnovations.ca/en/permalink/fpipub37730
Author
Wang, Brad J.
Dai, Chunping
Date
April 2005
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Green Veneer Clipping and Moisture Sorting by Brad Wang Composites Research
Author
Wang, Brad J.
Dai, Chunping
Date
April 2005
Material Type
Research report
Physical Description
29 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer
Measurement
Series Number
General Revenue Report Project No. 3972;3972
W-2162
Location
Vancouver, British Columbia
Language
English
Abstract
Based on extensive results from laboratory and mill studies, this report focuses on the characterization of green veneer moisture content (MC) and development of a mathematical model for green veneer MC variation, establishment of the optimum clipping width and Forintek’s improved green veneer sorting method for common softwood and hardwood species. Further, the economic benefits of improved green veneer clipping and sorting were analyzed. Finally, a computer simulation program, VSort, was developed to assist mills in performing optimum green veneer clipping and sorting. The key results show that:
the MC distribution appeared to be a dual-peak pattern for common softwood and hardwood species: one for heartwood veneer and the other for sapwood veneer, characterized by means and standard deviations of the two normal distributions. The position of the first peak (heartwood) was more consistent whereas the second peak (sapwood) varied more among logs;
the green veneer clipping should be based on the green veneer sorts with each of them having a target clipping width, which can be determined based on the shrinkage measurement of sapwood and heartwood of each species and the minimum allowable clipping width in the mill;
the green veneer sorting should be based on peak veneer MC and the size of wet spots on each veneer sheet instead of average veneer MC used currently in the mill;
with improved clipping strategy, veneer recovery can be improved by 1.0 to 2.0%, which can translate to an annual savings varying from $200,000 to $400,000 per mill;
with improved green veneer sorting strategy using Forintek’s new light transmission method, veneer drying productivity can be improved by 4.0 to 8.0% for green Douglas-fir veneer. The improvement in drying productivity also depends on the species and mill situation. Further, the improved veneer sorting helps significantly reduce the amount of overdried veneer. The improved green veneer sorting will translate to an annual savings varying from $400,000 to $800,000 per mill;
the VSort model can successfully characterize the MC distribution for common softwood and hardwood species and the relationship between peak veneer MC and average veneer MC in terms of clipping width. It can also assist mills perform optimum green veneer clipping, and establish the optimum cut-off MC levels of each sort for improved veneer drying and reduced energy consumption.
Veneers - Moisture content
Moisture content - Measurement
Veneers - Clipping
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Optimization of gluing, lay-up and pressing for Mountain Pine Beetle plywood

https://library.fpinnovations.ca/en/permalink/fpipub5607
Author
Wang, Brad J.
Dai, Chunping
Wharton, S.
Date
December 2005
Edition
37806
Material Type
Research report
Field
Wood Manufacturing & Digitalization
addressed veneer grading, gluing, panel lay-up and hot pressing. This project was a follow up to an earlier
Author
Wang, Brad J.
Dai, Chunping
Wharton, S.
Date
December 2005
Edition
37806
Material Type
Research report
Physical Description
54 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Wood
Veneer
Utilization
Plywood manufacture
Plywood
Laminate product
Insect killed
Gluing
Series Number
MPBI Project 8.08
W-2328
Location
Vancouver, British Columbia
Language
English
Abstract
The objective of this project was to investigate the possibility of increasing the value recovery from the Mountain Pine Beetle (MPB)-attacked Lodgepole Pine (Pinus contorta Dougl.) logs by adjusting the plywood manufacturing process specifically for the beetle-killed resource. The project addressed veneer grading, gluing, panel lay-up and hot pressing. This project was a follow up to an earlier study that demonstrated by segregating MPB logs, the productivity and material recovery could be improved at the early stages of production through narrower veneer clipping width, more accurate moisture sorting and higher drying productivity (Wang and Dai 2004). Based on the comparative results between the MPB veneer and non-affected control veneer from pilot plant tests and mill trials, this study found that the MPB veneer is denser and stronger than the control veneer from typical white wood mix. As long as manufacturing parameters are properly adjusted in drying, grading, gluing and hot-pressing, segregating MPB logs provides an opportunity to manufacture higher stiffness laminated veneer lumber (LVL) and plywood products with superior dry and wet gluebond performance for such applications as wood I-joists, headers and beams, flooring, decking and concrete forming. This could further offset to a large degree the reduction in material recovery and some appearance-based plywood products in the Japanese market. As well, this practice of segregation will become extremely important for recovering the highest value since the MPB-killed wood will be greater than 25% of total log supply in the mill with most of it being grey stage materials. The plywood production was affected by MPB logs as follows: The MPB veneer is lower in moisture content (MC), more brittle, and more difficult to handle. It also contains various degrees of bluestain. To increase material recovery and panel gluebond performance, veneer overdrying needs to be minimized. The machine vision technology currently used by some plywood/LVL mills cannot differentiate defects within the bluestained area. To improve veneer visual sorting, the existing vision systems can be upgraded to mask the effect of bluestain or to segregate the bluestained veneer from the non-stained veneer using a saturation color index. Compared to the control veneer, the MPB veneer is higher not only in dry bonding strength but also in wet bonding strength, measured by shear strength and percent wood failure. In the meantime, the MPB veneer is about 10% higher in average modulus of elasticity (MOE) and 20% higher in stress grade outturns, which can translate into more than $1.5 million additional savings for the mill annually when processing 10% of MPB-killed logs. To achieve optimum gluebond performance and minimum manufacturing cost for MPB plywood, glue spread can be kept at the same level as currently used by control plywood. However, the pressing time of 5-ply MPB plywood should be lengthened by about 10% compared to that used by 5-ply control plywood. As well, the assembly time should be reduced to about 10-15 min, keeping veneer temperature as low as possible. Furthermore, 5-ply plywood manufacturing trials and 13-ply LVL preliminary tests demonstrated that the MOE and modulus of rupture (MOR) of MPB plywood and LVL are about 15% and 20% higher than those of control plywood and LVL, respectively. As a result, the MPB veneer is more suitable for making higher stiffness LVL and specialty structural plywood products. By implementing this product strategy, the value recovery from the beetle-killed resource can be dramatically increased.
Insect-killed wood - Utilization
Gluing
Lumber, Laminated veneer
Plywood - Manufacture
Dendroctonus ponderosae
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Review of standard test procedures for assessing the delamination resistance of solid wood bondlines

https://library.fpinnovations.ca/en/permalink/fpipub37740
Author
Lum, Conroy
Casilla, Romulo C.
Date
March 2005
Material Type
Research report
Field
Sustainable Construction
Author
Lum, Conroy
Casilla, Romulo C.
Contributor
Natural Resources Canada. Canadian Forest Service.
Date
March 2005
Material Type
Research report
Physical Description
119 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Veneer gluing
Veneer
Mechanical properties
Laminate product
Joints
Gluing
Glue
Series Number
Value to Wood No. FCC4;3924
W-2136
Location
Vancouver, British Columbia
Language
English
Abstract
A review of delamination/durability tests was conducted, and tests were selected for comparative study. Reduced catalyst levels affected phenol-resorcinol formaldehyde (PRF) and catalyzed polyvinyl acetate (PVA) bond durability. Wood moisture content (MC) at the time of bonding affected PVA durability, but not PRF. Growth rate and density affected Douglas-fir bond durability. Density did not affect the results of slow-growth lodgepole pine. In laminated wood, although all five delamination tests accepted conforming and rejected non-conforming PRF, only two tests rejected both non-conforming PRF and PVA. In fingerjoined lumber, delamination was sensitive to the final MC. Specimen length affected specimen-drying time, but its effect on delamination was not consistent. The NLGA delamination suggested lower bond durability than the WWPA durability-bending test.
Glue - Tests
Glue - Strength
Lumber, Laminated veneer
Glued joints - Strength
Veneers - Gluing
Gluing - Defects
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