Skip header and navigation

6 records – page 1 of 1.

Development of standards for edge-glued and face-glued engineered products

https://library.fpinnovations.ca/en/permalink/fpipub41365
Author
Pirvu, Ciprian
Date
March 2007
Material Type
Research report
Field
Sustainable Construction
Author
Pirvu, Ciprian
Date
March 2007
Material Type
Research report
Physical Description
66 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Veneer
Mechanical properties
Specifications
Laminate product
Joints
Gluing
Specification
Series Number
Value to Wood No. FCC 58
W-2384
Location
Vancouver, British Columbia
Language
English
Abstract
Forintek has completed a two-year investigation of the NLGA SPS 6 Standard, Special Products Standard for Structural Face-Glued Lumber. The NLGA SPS 6 Standard prescribes product specifications and qualification and quality control requirements for structural products created by edge-gluing and/or fingerjoining lumber segments. Under the NLGA SPS 6 Standard, the design values assigned are based on the visual grade and the stress level achieved in qualification tests on the glue joints. The project assessed the effect of the following three factors on strength of the NLGA SPS 6 product: 1. Tension proof-loading; 2. Relative location of fingerjoints in adjacent members when fingerjoined material is edge-glued; 3. Strength of the material used to make the NLGA SPS 6 product. Results showed a positive effect of proof-loading, a minor effect of staggering of fingerjoints, and a highly significant effect of density of raw material on tensile stress of edge-glued specimens. It was confirmed that SPS6 products of greater commercial value can be obtained from lower grade lumber. However, visual grading of SPS 6 products proved to be more difficult than visual grading of lumber, because grade-determining wood characteristics were sometimes hidden in the bond line, and could not be properly identified. The findings of this project can be used to fine tune the NLGA SPS 6 standard and the other NLGA fingerjoint and face-glued lumber product standards. The project will help the wood industry maximize the utilization of their raw material resource, resulting in increased profitability.
Structural timbers - Mechanical properties
Gluing - Specifications
Lumber - Gluing
Glued joints - Finger
Glued joints - Edge
Glued joints - Specifications
Lumber, Laminated veneer - Strength
Documents
Less detail

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
Less detail

Integrated protection of structural composites for exterior exposure

https://library.fpinnovations.ca/en/permalink/fpipub41360
Author
Morris, Paul I.
Wang, Jieying
Ingram, Janet K.
Date
March 2007
Material Type
Research report
Field
Sustainable Construction
Author
Morris, Paul I.
Wang, Jieying
Ingram, Janet K.
Date
March 2007
Material Type
Research report
Physical Description
15 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Veneer
Preservatives boron
Preservatives
Preservation
Laminate product
Beams
Series Number
Value to Wood No. FCC 24;4413
W-2361
Location
Vancouver, British Columbia
Language
English
Abstract
An above-ground field test of glulam and laminated veneer test samples protected by a combination of coating and treatment with borate by two alternative processes was initiated. Assessment of coating and sample preparation are described.
Documents
Less detail

Minimizing glue dry-out and delamination in plywood. Part 1: softwood plywood

https://library.fpinnovations.ca/en/permalink/fpipub37853
Author
Xu, H.
Dai, Chunping
Chow, Gordon
Andersen, Axel W.
Date
October 2007
Material Type
Research report
Field
Wood Manufacturing & Digitalization
Author
Xu, H.
Dai, Chunping
Chow, Gordon
Andersen, Axel W.
Date
October 2007
Material Type
Research report
Physical Description
46 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer gluing
Veneer
Plywood manufacture
Plywood
Laminate product
Gluing
Series Number
4574
W-2461
Location
Vancouver, British Columbia
Language
English
Abstract
This work provides scientific support for, and confirms, what most mills already use as rough and dirty rules of thumb as best practices for manufacturing plywood: i.e. dry veneer should be pressed when its temperature is 100°F or less; average veneer moisture can be 4 %; assembly times should not exceed 20 minutes; and glue spreads should be approximately 32 lbs. per M ft2 SGL. In addition, this report used the data generated to formulate multivariate statistical models that could be used to develop or enhance existing in-mill process control software, and/or quality procedures at member operations. This report documents the results of an extensive investigation of plywood dryout and delamination. The study included laboratory and mill tests of key manufacturing variables used in the production of phenol formaldehyde (PF) bonded plywood. Relationships between key variables and plywood quality were used to develop a statistical equation to quantify the effect of veneer moisture content, temperature, assembly time and glue spread rate on wood failure percentage. Testing methods using vacuum/pressure boil-dry-boil, and 6-cycle soak were used and a new multi-step pressing schedule was examined. The following are the main findings:
Veneer with a low moisture content (MC) level is more likely to create glueline dryout than high MC sheets when PF resin is used. Although veneer with a high MC level could minimize the occurrence of dryout, PF gluing systems accept a maximum allowable veneer MC (peak moisture) range of 6 to 8%.
Sheets having temperatures over 100°F are strongly correlated with dryout problems.
An excessively long assembly time approaching 20+ minutes could significantly affect bonding, especially when veneer or ambient temperatures are high.
Increasing glue spread rate can be used to minimize dryout caused by high veneer temperature and low veneer MC; however, a higher glue cost per M ft2 is incurred.
Flexure tests cannot be relied upon to detect bond quality as bending strength is heavily influenced by surface panel properties. During the mill study, it was learned that variations within each of the above mentioned controllable factors could not be avoided in a mill situation. Good manufacturing process control can ensure that all variables stay within ideal ranges and occurrences of dryout are minimized. The statistical models developed during this project could, possibly, be used to develop or enhance process control software. A multiple-step hot-pressing schedule, capable of improving plywood bonding properties with or without sacrificing volume recovery, was developed to minimize bond problems caused by dryout. Existing mill presses may be able to implement this approach seamlessly or after a few minor adjustments have been made. Some mills may have to peel thicker veneer to compensate for increased veneer compression associated with multi pressing and in doing so sacrifice log recovery. Pressing schedules illustrated in this study indicate that press production is not sacrificed as single or multi-step pressing time is identical for most thicknesses. Laboratory tests showed that wood failure percentage figures from a glueline shear test, a standard method for evaluating bond quality, are useful glue dry-out indicators for softwood plywood. An attempt to develop a tack strength test that could assist in evaluating dryout was unsuccessful as excessive variation was present within recorded data.
Veneers - Gluing
Lumber, Laminated veneer - Gluing
Plywood - Manufacture
Documents
Less detail

Minimizing glue dry-out and delamination in plywood. Part 2: hardwood plywood

https://library.fpinnovations.ca/en/permalink/fpipub37854
Author
Xu, H.
Dai, Chunping
Chow, Gordon
Andersen, Axel W.
Date
October 2007
Material Type
Research report
Field
Wood Manufacturing & Digitalization
the effect of veneer moisture content, temperature, assembly time, glue spread rate, and amount of catalyst
Author
Xu, H.
Dai, Chunping
Chow, Gordon
Andersen, Axel W.
Date
October 2007
Material Type
Research report
Physical Description
16 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer gluing
Veneer
Plywood manufacture
Plywood
Laminate product
Gluing
Series Number
4574
W-2462
Location
Vancouver, British Columbia
Language
English
Abstract
An extensive investigation of plywood dryout and delamination was conducted in this study. It included laboratory tests of key variables for urea formaldehyde (UF) bonded plywood. A statistical equation was developed to quantify the effect of veneer moisture content, temperature, assembly time, glue spread rate, and amount of catalyst on wood failure percentage. The following are the main findings:
Veneer with a low moisture content (MC) level is more likely to create glueline dryout than high MC sheets when UF resin is utilized. Although veneer with a high MC level could minimize the occurrence of dryout, maximum allowable veneer MC (peak MC) is limited by other factors. UF gluing systems can employ a maximum MC range of 10 to 12%, which is much higher than the one that applies to PF resin (6 to 8%).
Sheets having temperatures over 100°F are strongly correlated with dryout problems.
An excessively long assembly time could significantly affect bonding, especially when veneer or ambient temperatures are high.
Increasing glue spread rate can be used to minimize dryout caused by high veneer temperature and low veneer MC.
In UF gluing systems, catalyst level heavily influences bonding and the extent to which dryout occurs.
Veneers - Gluing
Lumber, Laminated veneer - Gluing
Plywood - Manufacture
Documents
Less detail

Online measurement of plywood glue quality

https://library.fpinnovations.ca/en/permalink/fpipub37833
Author
Groves, C. Kevin
Date
April 2007
Material Type
Research report
Field
Wood Manufacturing & Digitalization
methods for enabling veneer mills to continuously monitor glue spread over the entire veneer surface
Author
Groves, C. Kevin
Date
April 2007
Material Type
Research report
Physical Description
12 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Veneer gluing
Veneer
Quality control
Qualitative analysis
Process control
Plywood
Gluing
Series Number
4576
W-2428
Location
Vancouver, British Columbia
Language
English
Abstract
The main objective of this project was to determine practical methods for enabling veneer mills to continuously monitor glue spread over the entire veneer surface during production and to alert mill personnel to problems as they occur. Several mills were visited to determine the main factors affecting glue coverage and uniformity for roll spreaders, curtain coaters, foam extruders and spray applicators. For each of these applicator types, the feasibility for online spread measurement was assessed based on observations and discussions with mill personnel. It was observed that with all applicator types, problems are a common occurrence due to a wide range of factors ranging from viscosity fluctuations and flow blockages to veneer surface roughness. It is apparent that mills could greatly benefit from having an automated system for real time monitoring of glue application quality for detecting glue deficiency and providing valuable feedback for the mill to minimize problems such as poor bonding, delamination, etc. From the experimental phase of the project, it was demonstrated that near IR (infra-red) light could be used to probe through phenolic glue coatings on veneer with results linking the degree of IR light absorption to the coating thickness (R² > 0.95). Tests also showed the feasibility of using this method for urea formaldehyde (UF) glue mixes. Based on the findings a computerized, optical scanning system was developed using tungsten halogen work lights as an IR source and an IR sensitive camera as the detector. For the setup, lights were angled downward at 45 degrees to illuminate the full width of the veneer surface with the camera mounted directly above the illuminated area to measure the IR reflectance. A computer with imaging software developed by Forintek was used to record the readings and calculate the glue spread. To simulate mill conditions, the entire system was mounted on a laboratory veneer conveyor and then used for scanning full-size veneer sheets at production line speeds. Pilot plant tests and a subsequent mill trial demonstrated that the scanning system was effective for continuous, online measurement of phenolic glue spread over the entire surface area of 4x8-foot veneers. Following this project, Forintek has planned to facilitate the transfer of this technology to industry through involvement with a project to install an advanced prototype scanning system at a Forintek member mill.
Veneers - Gluing
Plywood - Gluing - Tests
Gluing - Processes - Quality control
Computerized process control
Documents
Less detail

6 records – page 1 of 1.