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Computer simulation model of hot-pressing process of LVL and plywood products

https://library.fpinnovations.ca/en/permalink/fpipub5575
Author
Wang, Brad J.
Yu, C.
Date
April 2003
Edition
37655
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Wang, Brad J.
Yu, C.
Date
April 2003
Edition
37655
Material Type
Research report
Physical Description
23 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer
Simulation
Plywood
Panels
Materials
Laminate product
Hot press
Gluing
Series Number
2019
W-1965
Location
Vancouver, British Columbia
Language
English
Abstract
Laminated Veneer Lumber (LVL) and plywood are the two major veneer-based wood composite products. During LVL/plywood manufacturing, the hot pressing process is crucial not only to the quality and productivity, but also to the performance of panel products. Up to now, the numerical simulation of the hot-pressing process of LVL/plywood products is not available. To help understand the hot-pressing process of veneer-based wood composites, the main objective of this study was to develop a computer simulation model to predict heat and mass transfer and panel densification of veneer-based composites during hot-pressing. On the basis of defining wood-glue mix layers through the panel thickness, a prototype finite-element based LVL/plywood hot-pressing model, VPress®, was developed to simulate, for the first time, the changes of temperature, moisture and vertical density profile (VDP) of each veneer ply and glueline throughout the pressing cycle. This model is capable of showing several important characteristics of the hot-pressing process of veneer-based composites such as effect of glue spread level, veneer moisture, density, platen pressure and temperature as well as pressing cycles on heat and mass transfer and panel compression. Experiments were conducted using several different variables to validate the model. The predicted temperature profiles of the veneer plies and gluelines (especially at the innermost glueline) by the model agree well with the experimental measurements. Hence, the model can be used to evaluate the sensitivity of the main variables that affect hot-pressing time (productivity), panel compression (material recovery) and vertical density profile (panel stiffness). Once customized in industry, the new model will allow operators to optimize the production balance between productivity, panel densification and panel quality or stiffness. This hot-pressing model is the first step in facilitating the optimization of the pressing process and enhanced product quality.
Veneers
Panels - Production - Computer simulation
Density - Computer simulation
Composite materials - Density
Plywood - Density
Lumber, Laminated veneer
Gluing - Processes - Hot press
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Improving productivity, recovery and quality of veneer products with a new pressing method

https://library.fpinnovations.ca/en/permalink/fpipub37840
Author
Wang, Brad J.
Dai, Chunping
Date
March 2007
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Wang, Brad J.
Dai, Chunping
Contributor
Forestry Innovation Investment
Date
March 2007
Material Type
Research report
Physical Description
33 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer
Laminate product
Hot press
Gluing
Series Number
Recipient Agreement No.: FII-MDP-07-0015
Contract No.:2007-5423
W-2440
Location
Vancouver, British Columbia
Language
English
Abstract
Hot pressing is a critical stage in plywood and laminated veneer lumber (LVL) manufacturing. In this study, a new hot pressing method was developed for plywood and LVL products, which integrated both pressure control and position control in one pressing cycle. The optimum pressing parameters and resulting benefits of this method were determined for panels made from stress graded Douglas-fir, white spruce and mountain pine beetle (MPB) veneer through laboratory tests and for white spruce-lodgepole pine-subalpine fir (SPF) veneer through full-size panel tests. The method was further successfully applied in a mill trial using an industrial multi-opening plywood press.
Lumber, Laminated veneer - Manufacture
Gluing - Processes - Hot press
Documents
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OSB adhesives hot pressing - model : cure kinetic module

https://library.fpinnovations.ca/en/permalink/fpipub42028
Author
Sean, Trek
Date
March 2001
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Sean, Trek
Contributor
Canada. Canadian Forest Service
Date
March 2001
Material Type
Research report
Physical Description
13 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Simulation
Pressing
Hot press
Series Number
Canadian Forest Service No. 27
E-3532
Location
Sainte-Foy, Québec
Language
English
Abstract
The work described in this report involved examination of the development of IB strength in OSB panels as a function of pressing parameters and mat moisture content. Response surface methodology (RSM) was used in the design the experimental work employing a Box-Behnken design with four (4) variables (platen temperature, pressing time, moisture content (MC) of the face layers of the mat and face/core ratio). Results showed that the relationship between the study parameters and IB strength fits very well the form of quadratic polynomials. Within the limits studied, it was found that increasing the pressing time and/or temperature could significantly improve the IB strength in OSB panels. Also, the study showed that bonding strength is improved by reducing mat moisture content. The work is also involved with the effect of resin kinetic on the bonding strength development. Several commercial phenol formaldehyde core resin were selected and characterised with a thermal analysis technique (DSC) to compare the chemical reactions and curing behaviour. The automated bonding evaluation apparatus or slap-shear test was employed to evaluate strength development of the selected adhesives as function of time, temperature and furnish moisture content. Test results showed that within the limits studied, increasing the pressing time and/or temperature could significantly improve the bonding shear. Also, the study showed that furnish moisture content and energy activity of the resin have limited effect on the bonding strength. The study on the development IB strength as a function of resin energy activity, pressing temperature, pressing time and mat moisture content at the face layers, showed a significant effect of pressing time and temperature on the IB strength of the panel. Also resin with high activity energy was found to provide panel with low IB.
Hot pressing
Simulation Model
Documents
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OSB adhesives hot pressing - model : cure kinetic module

https://library.fpinnovations.ca/en/permalink/fpipub41910
Author
Sean, Trek
Date
January 1999
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Sean, Trek
Contributor
Canada. Canadian Forest Service
Date
January 1999
Material Type
Research report
Physical Description
2 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Simulation
Pressing
Hot press
Series Number
CFS Simple Progress Report
E-3351
Location
Sainte-Foy, Québec
Language
English
Abstract
Hot pressing
Simulation Model
Documents
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