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Production and properties of sustainable wood-
welded panels from North American species
Benoît Belleville, UlavalTatjana Stevanovic, Ulaval
Antonio Pizzi, ENSTIBAlain Cloutier, Ulaval
June 19 2011
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Plan of presentation
• Introduction and problematic
•Bibliographical review
•Objectives of research
•Results and discussion
•Conclusions and perspectives
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Introduction
•Rotational wood-dowel welding has been
shown to rapidly produce wood joints of
considerable strength without any adhesive.
•Mechanical properties similar to PVA
adhesive.
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Wood-dowel welding: How ?
•Mechanical friction at the interface;
•Temperature-induced softening and
degradation of polymer material;
•Composite formation: fibers/molten wood
material matrix.
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Wood-dowel welding mechanism
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Wood-dowel welding: The interest ?
• Interesting and sustainable alternative for
paneling applications
•Green technology (only wood)
•Opportunity to increase productivity and
reduce costs in the furniture industry
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Problematic
•Evaluate the suitability of two North American
hardwood species, sugar maple (Acer
saccharum) and yellow birch (Betula
alleghaniensis) for the design of panels using
wood-dowel welding technology.
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Specific objectives
•Produce wood welded panels
•Evaluate mechanical properties under
constant and varying hygrometric conditions
•Compare with its PVA-glued counterpart
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Material and Methods: Paneling
•Wood-dowel welding performed with a
machine designed for paneling purposes.
•12 panels produced for each species
•6 PVA-glued panels produced for each
species in parallel for comparative purposes
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Material and Methods: Paneling
•25x30x225 mm wood slats (12 per panel)
• Insertion along the edge and through
neighbouring slat (~50 mm)
•Dowels configuration
•2.5 cm spacing between dowels and from edges
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Material and Methods: Welding parameters
•Commercial smooth wood dowels (Ф 9.67 mm)
in pre-drilled hole (Φ 7,67 mm)
•Optimized wood-dowel welding parameters for
individually studied species
•Sugar maple : 1000 RPM, 25.0 mm s-1
•Yellow birch : 1000 RPM, 16.7 mm s-1
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Material and Methods
•Panels tested following a typical protocol for
wood composite panels
•Three-point bending test
•Delamination following multiple cycles at
different hygrometric conditions
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Material and Methods: Three-point bending test
MTS QT 5 KN universal testing machine
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Material and Methods: Three-point bending test
•Load concentrated at center
•Dowels not continuous
throughout the panel (50 mm)
[1]
•Estimated load at break (σmax)
Yellow birch: 1502 N
Sugar maple: 1630 N
3
maxmax 2
D
LF
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Material and Methods: Delamination
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Results and discussion: Bending
•2 types of failure: Centre of
the panel or next to it.
•Fracture always in the dowels
•No slippage along weldline
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Results and discussion: Bending
Table 1. Average bending strength results
1Standard error
Species Type of
laminated joint
Fmax ±SE1
N
Estimated Fmax
(eq.1)
N
Sugar maple
Welded 1696.4 (136.2) 1630
Glued 5746.1 (764.9) -
Yellow birch
Welded 1790.2 (38.4) 1502
Glued 5212.7 (521.9) -
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Results and discussion: Delamination
•No deformation observed in panels submitted
to conditioning cycles.
•Delamination observed in both types only
under dry conditions although not affecting
bending properties.
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100% sugar maple
No adhesive
66 cm wide (26’’)
46 cm high (18’’)
36 cm deep (14¼’’)
228 wood dowels
Small-scale crib
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Conclusions and perspectives
•Welded bond joint is not the weakest link
affecting panel mechanical properties.
•Wood-dowel welding is suitable for paneling
of North American species.
•Additional work required to improve the
automated assembling technique and panel
stability.
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Acknowledgements and partners
Thank you for your attention!