CA1301618C - Low amplitude wave-board - Google Patents
Low amplitude wave-boardInfo
- Publication number
- CA1301618C CA1301618C CA000602085A CA602085A CA1301618C CA 1301618 C CA1301618 C CA 1301618C CA 000602085 A CA000602085 A CA 000602085A CA 602085 A CA602085 A CA 602085A CA 1301618 C CA1301618 C CA 1301618C
- Authority
- CA
- Canada
- Prior art keywords
- panel
- amplitude
- wafers
- board
- wave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/20—Moulding or pressing characterised by using platen-presses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N5/00—Manufacture of non-flat articles
Abstract
"LOW AMPLITUDE WAVE-BOARD"
ABSTRACT OF THE DISCLOSURE
A low amplitude waveboard panel having improved bending strength and bending stiffness properties is provided. More specifically, the amplitude of the waves is substantially equal to, or less than the thickness of said board. Preferably, the wave amplitude ranges from between 1/8" to about 1".
ABSTRACT OF THE DISCLOSURE
A low amplitude waveboard panel having improved bending strength and bending stiffness properties is provided. More specifically, the amplitude of the waves is substantially equal to, or less than the thickness of said board. Preferably, the wave amplitude ranges from between 1/8" to about 1".
Description
13016~8 FIELD OF THE INVENTION
2 The present invention relates to a low amplitude wood composite 3 board panel having an undulating, or wave-like, configuration.
Typically, a wafer board panel comprises layers of wood 6 flakes or wafers formed into a composite structure using a 7 resinous binder. ~he preparation of wafer board panels is 8 complex, but broadly consists of two principal stages. The first g stage comprises the preparation of the wafers and admixing thereof with the binder to form a loose layer or mat; the second 11 stages involves subsequent compression and heating of the mat to 12 cure the binder and form the consolidated panel.
13 At present, wafer board is usually manufactured in the 14 form of planar or flat sheets. Wafer board is a recognized structural panel, finding wide application in the construction 16 industry, particularly as a plywood substitute in residential 17 construction.
18 Improvement in performance characteristics of flat 19 wafer board panels has been attained by optimisation of such parameters as wafer orientation, wafer geometry, resin selection 21 and content, and the like.
22 By wafer orientation is meant orientation through a 23 degree of rotation which may range from the longitudinal to the 24 transverse directions. Furthermore the orientation may take place in a layered or non-layered manner. Stated otherwise, the 26 outer faces of the board only may contain orientated wafers 27 whereas the core may contain wafers in random orientation.
28 Alternatively, the orientation may be such that all the layers 130~618 1 throughout the board are consistently aligned in one direction.
2 After exhaustive optimization studies of planar wafer 3 board panels it was postulated that its flexural strength 4 characteristics could ~e improved if a corrugated configuration was imparted thereto. The fundamental concept of corrugat~ng 6 materials to thereby improve the structural properties is not a 7 novel one. Indeed, corrugated wafer board panels per se have 8 previously been manufactured in the industry. However, ~he wafer g board panels prepared by these prior art techniques do not have the desired structural strength properties because they do not 11 have a substantially uniform density.
12 Until recently, wafer board panels were manufactured in 13 the form of planar or flat sheets. However, as disclosed in U.S.
14 Patent 4,616,991, the present applicant has developed an apparatus and process for the manufacture of panels having a 16 wave-like or corrugated configurat-ion. Such waveboard panels have 17 improved structural strength properties, relative to planar 18 panels.
19 This prior patented apparatus involved a pair of opposed, spaced-apart, upper and lower platens. Each platen was 21 formed of adjacent lengths of chain-like links. When the lengths 22 were pushed inwardly from the side, they would shift from a 23 planar to an undulating corrugated form.
24 The process steps involved:
- distributing a mat of loose wood wafers between 26 the upper and lower platen surfaces while they are 27 maintained in the planar configuration;
28 biasing the platens together to pre-compress the 29 mat, and thereby substantially fixing the wafers 130~618 1 together to limit their further relative movement;
2 - converting the two platen surfaces, still in 3 pressing association with the mat, from the planar 4 to the corrugated configuration; and - then applying additional pressure and heat for a 6 sufficient time to cure the binder and produce a 7 corrugated waveboard panel.
8 The main advantage inherent in the patented process was g that the panel product so formed was characterized by a substantially uniform density. This was achieved because the 11 wafers were fixed by the pre-compression step and because the mat 12 was not significantly stretched or elongated during the 13 conversion from the planar to the corrugated configuration.
14 It will be also noted that the product formed using the particular mechanical assembly described hereabove has a 16 generally sinusoidal configuration. The peaks and troughs of the 17 panel have a generally rounded profile. The amplitude of the 18 waves of such panels would range from 12mm to 50mm. By amplitude 19 is meant the distance between the centroid (or zero lineJ and the wave crest. Wave length is defined as the distance between two 21 adjacent wave crests. By low amplitude waveboard as defined 22 herein is meant waveboard having an amplitude substantially equal 23 to the board thickness in the ranges defined hereinafter.
24 Whilst the above-described apparatus provides a useful product it will be readily appreciated by one skilled in the art 26 that the cost of manufacture of such corrugating platens is 27 significant.
28 In summary, therefore, prior to the development of the 29 present invention, it had been appreciated that by having a high ~301618 1 amplitude waveboard prepared using the above-described platen 2 assembly a marked improvement in mechanical performance 3 characteristics was obtained. However, what had not been 4 realised was that providing even a minor degree, or very low amplitude of corrugation to the board would result in mar~edly 6 improved properties as compared to a planar panel.
7 SUNMARY OF l'HE INVENTION
8 In accordance with the present invention a low g amplitude waveboard panel having improved bending strength and bending stiffness properties is provided. More specifically, in 11 order to obtain this improvement the wave amplitude must be 12 substantially equal to or less than the thickness of said board.
13 Preferably, the amplitude of said waves would range from between 14 about 1/8" to about l".
Preferably, the panels would be prepared from wood 16 wafers in admixture with a binder.
17 Additionally, it has been observed that by 18 substantially orientating or aligning the entire content of the 19 wafers in a direction generally parallel to the profile of the wave-front it is possible to greatly increase the bending 21 stiffness of the waveboard. Even partial alignment of the wafers 22 has been found to increase the performance properties of the 23 waveboard.
24 In a second aspect of the invention, it has been found that the low amplitude waveboard may be manufactured by the 26 simple expedient of mounting suitably spaced elongate rectangular 27 iron bars or the like, on both the upper and lower press platens.
13016i8 1 Thus, when the press is in the closed position the space between 2 the working face of the iron bar and the surface of the press 3 platen defines the amplitude of the waveboard.
4 It is to be noted, however, that when utilizing such an assembly, the mat of wafers plus binder in admixture must be 6 placed between a pair of flexible screen members before 7 positioning between the platens. As a result of this provision, 8 it is effectively possible to avoid the displacement or g ~stretching~' of the wafers in the zone between corners of opposed upper and lower bars, which would otherwise take place.
11 The advantages arising from the present invention thus 12 involve a product which can be relatively simply and 13 inexpensively manufactured yet which exhibits marked improvement 14 in performance characteristics.
Broadly stated the invention comprises a board formed 16 of a composite material said board having at least one half wave 17 formed therein wherein the amplitude of the wave is substantially 18 equal to or less than the thickness of said board.
Figure 1 is a comparative illustration of the profiles 21 of sinusoidal corrugated waveboard, low amplitude waveboard and 22 planar waferboard to accompany the panel property values thereof 23 which are detailed in Table I herein.
24 Figure 2 is a perspective view of a finished waveboard panel.
26 Figure 3 is a schematic illustrating the press steps 27 employed in the process of the present invention.
28 Figure 4 is a side-sectional detailing the dimensions ~30~6~8 1 of the board.
2 DESCRIPTION OF THE PREFERRED EM~ODIMENT
3~aving reference to the accompanying drawings there is 4shown at 1 the press system utilized to manufacture the low 5amplitude waveboard.
6More specifically, upper and lower platens 2a and 2b 7respectively, each include a base plate 3.
8A plurality of spaced apart, parallel longitudinally 9extending rectangular bars 4 are affixed to the working surface 10of the base plates 3.
11In order to obtain a low amplitude waveboard of 12thickness "A" and wave-length "B" the platens would be arranged 13as shown in the figures.
14The horizontal platen assemblies are arranged in spaced 15apart opposed relationship as shown in Figure 3. Conventional 16press members (not shown) are connected to the platen assemblies 172, for biasing the latter together in a vertical direction and 18applying pressure thereto.
19As would be evident to one skilled in the art, the 20waveboard may be manufactured form a variety of suitab~e 21materials, exemplary of which would be wood composite materials.
22The process for producing the low amplitude waveboard 23from wood wafers was as follows:
24The furnish could be prepared using various wood 25species. Aspen logs approximately 8" length and 6 - 14" in 26diameter were used. The logs were cleaned, debarked waferized 27and screened in accordance with conventional methods. The strand 28or wafer length could range from 2~ mm to 300 mm, but preferably 13016~8 1 would be 50 mm to 100 mm for the best results. The thickness of 2 the wafers was about 0.75 mm. The width of the strands may range 3 up to 50 mm.
4 The moisture content of the furnish was reduced from the green state to about 5% using commercial dryers. The wafers 6 were screened following drying.
7 At 5~ moisture content, the furnish was blended with 8 about 2~ to 3% by weight of powdered phenol formaldehyde resin 9 and 1~ by weight wax in a drum blender. Wax was utilized to improve the moisture resistance of the panel. ~esin was used as 11 a binder for the wafers.
12 The wafers and wax/resin or binder, in admixture were 13 arranged loosely between two flexible screens to form the mat.
14 Alternatively and advantageously the wafers may be orientated (using methods conventional in the art) parallel to the profile 16 of the wave-front. By arranging the wafers in this manner, I
17 have determined that the bending stiffness of the panel may be 18 approximately doubled, as shown in Table III herebelow.
19 The quantity of wafers and resin used was sufficient to produce a board having a density of 600 - 800 kg/m3.
21 In order to avoid having areas of lower density in the 22 panel in the sone marked "Z", I have determined that it is 23 essential to uniformly spread the mat between flexible screens 24 before placing it between the platens. Suitable screens could be manufactured from such exemplary materials as high tension carbon 26 steel mesh wire screen type #163 supplied by Gerald Daniel & Co.
27 Inc., N.Y.
28 In the press, the mat was subjected simultaneously to 29 high temperature, which cured the resin and to high pressure ~3016~8 l which compressed the mat to its specified thickness. The platen 2 temperature was maintained at 205c.
3 Table I given herebelow provides a comparison of the 4 panel properties of the sinusoidal corrugated waferboard, low amplitude and planar waferboard illustrated in Figure 1. The low 6 amplitude panels were made using the malelfemale press platens 7 illustrated in Figure 3.
g (ControlJ Low Flat Amplitude 11 Panel Propertieswaferboardwaferboard 12 Panel density (kg/m3)665 643 13 Unit panel mass rkg/m2) 7.7 7.6 14 Wavelength (mm) -- 114 Panel depth (mmJ 11.6 25 16 Skin thickness (mmJ 11.6 11.6 17 MC (~) 3.6 3.9 18 Unit max. moment 19 (NmmlmmJ 587 943 Bending stiffness 21 Unit El (Nmm2/mm) 724,000 2,460,000 22 All the panels were prepared in the above example using 23 random oriented flakes. All panels were manufactured using 75 mm 24 long aspen flakes of 0.75 mm thickness. The weight of powdered phenolic resin was 3%.
26 Table II given herebelow shows the panel properties of 130~618 1 two different density low amplitude waveboard panels compared to 2 flat waferboard. The panels were prepared using the press 3 platens and flexible screen system described herein. The wafer 4 orientation was random.
TABLE II
6 (ControlJ Low Low 7 Flat Amplitude Amplitude 8 Panel Properties waferboard waferboard waferboard g Normal High Normal Density Density Density 11 Panel density (kg/m3J665 801 661 12 Unit panel mass (kg/m2J 4.1 5.5 4.0 13 Wavelength (mmJ -- 89 89 14 Panel Depth (mmJ 6.2 12.7 12.7 Skin Thickness (mm) 6.2 6.8 6.1 16 MC (%) 3.3 3.6 4.1 17 Unit max. moment (M maxJ
18 (Load Capacity) (Nmm/mm) 168 368 247 19 Bending stiffness Unit E1 (Nmm2/mm) 96,600 504,000 322,000 21 In Table III herebelow there is provided a comparison 22 between low amplitude waveboard having strongly orientated wafers 23 versus low amplitude waveboard having randomly orientated wafers.
24 By "strongly" orientated wafers is meant that a major portion of the wafers, throughout its thickness, are orientated in one 26 direction, specifically parallel to the major axis of the wave 27 front.
1~10~618 TABLE III
2 Low Arnplitude (Control) 3 Corrugated Flat 4 Panel PropertiesWaferboard Waferboard Wafer Orientation*StrongMedium Random Random 6 Relative to Test 7 Span 8 Panel Density (kg/m3J 644 660 638 642 g Unit Panel Mass (Kg/m2) 4.1 4.1 4.0 4.2 ~avelength (mmJ 89 89 89 __ 11 Panel Depth (mm) 13.1 12.8 12.8 6.5 12 Skin Thickness (mm) 6.4 6.2 6.3 6.5 13 MC (%) 3.9 3.6 4.1 3.4 14 Unit Max. Moment (load Capacity) (Nmm/mm) 16 (M max) 377 346 221 147 17 Bending Stiffness 18 (Nmm2/mm) 641,000 496,000 326,000 94,000 19 Replications (-) 8 4 8 8 *The wafer orientation for each panel was the same in face and 21 core layers unlike that for commercial oriented flat waferboard.
13 At present, wafer board is usually manufactured in the 14 form of planar or flat sheets. Wafer board is a recognized structural panel, finding wide application in the construction 16 industry, particularly as a plywood substitute in residential 17 construction.
18 Improvement in performance characteristics of flat 19 wafer board panels has been attained by optimisation of such parameters as wafer orientation, wafer geometry, resin selection 21 and content, and the like.
22 By wafer orientation is meant orientation through a 23 degree of rotation which may range from the longitudinal to the 24 transverse directions. Furthermore the orientation may take place in a layered or non-layered manner. Stated otherwise, the 26 outer faces of the board only may contain orientated wafers 27 whereas the core may contain wafers in random orientation.
28 Alternatively, the orientation may be such that all the layers 130~618 1 throughout the board are consistently aligned in one direction.
2 After exhaustive optimization studies of planar wafer 3 board panels it was postulated that its flexural strength 4 characteristics could ~e improved if a corrugated configuration was imparted thereto. The fundamental concept of corrugat~ng 6 materials to thereby improve the structural properties is not a 7 novel one. Indeed, corrugated wafer board panels per se have 8 previously been manufactured in the industry. However, ~he wafer g board panels prepared by these prior art techniques do not have the desired structural strength properties because they do not 11 have a substantially uniform density.
12 Until recently, wafer board panels were manufactured in 13 the form of planar or flat sheets. However, as disclosed in U.S.
14 Patent 4,616,991, the present applicant has developed an apparatus and process for the manufacture of panels having a 16 wave-like or corrugated configurat-ion. Such waveboard panels have 17 improved structural strength properties, relative to planar 18 panels.
19 This prior patented apparatus involved a pair of opposed, spaced-apart, upper and lower platens. Each platen was 21 formed of adjacent lengths of chain-like links. When the lengths 22 were pushed inwardly from the side, they would shift from a 23 planar to an undulating corrugated form.
24 The process steps involved:
- distributing a mat of loose wood wafers between 26 the upper and lower platen surfaces while they are 27 maintained in the planar configuration;
28 biasing the platens together to pre-compress the 29 mat, and thereby substantially fixing the wafers 130~618 1 together to limit their further relative movement;
2 - converting the two platen surfaces, still in 3 pressing association with the mat, from the planar 4 to the corrugated configuration; and - then applying additional pressure and heat for a 6 sufficient time to cure the binder and produce a 7 corrugated waveboard panel.
8 The main advantage inherent in the patented process was g that the panel product so formed was characterized by a substantially uniform density. This was achieved because the 11 wafers were fixed by the pre-compression step and because the mat 12 was not significantly stretched or elongated during the 13 conversion from the planar to the corrugated configuration.
14 It will be also noted that the product formed using the particular mechanical assembly described hereabove has a 16 generally sinusoidal configuration. The peaks and troughs of the 17 panel have a generally rounded profile. The amplitude of the 18 waves of such panels would range from 12mm to 50mm. By amplitude 19 is meant the distance between the centroid (or zero lineJ and the wave crest. Wave length is defined as the distance between two 21 adjacent wave crests. By low amplitude waveboard as defined 22 herein is meant waveboard having an amplitude substantially equal 23 to the board thickness in the ranges defined hereinafter.
24 Whilst the above-described apparatus provides a useful product it will be readily appreciated by one skilled in the art 26 that the cost of manufacture of such corrugating platens is 27 significant.
28 In summary, therefore, prior to the development of the 29 present invention, it had been appreciated that by having a high ~301618 1 amplitude waveboard prepared using the above-described platen 2 assembly a marked improvement in mechanical performance 3 characteristics was obtained. However, what had not been 4 realised was that providing even a minor degree, or very low amplitude of corrugation to the board would result in mar~edly 6 improved properties as compared to a planar panel.
7 SUNMARY OF l'HE INVENTION
8 In accordance with the present invention a low g amplitude waveboard panel having improved bending strength and bending stiffness properties is provided. More specifically, in 11 order to obtain this improvement the wave amplitude must be 12 substantially equal to or less than the thickness of said board.
13 Preferably, the amplitude of said waves would range from between 14 about 1/8" to about l".
Preferably, the panels would be prepared from wood 16 wafers in admixture with a binder.
17 Additionally, it has been observed that by 18 substantially orientating or aligning the entire content of the 19 wafers in a direction generally parallel to the profile of the wave-front it is possible to greatly increase the bending 21 stiffness of the waveboard. Even partial alignment of the wafers 22 has been found to increase the performance properties of the 23 waveboard.
24 In a second aspect of the invention, it has been found that the low amplitude waveboard may be manufactured by the 26 simple expedient of mounting suitably spaced elongate rectangular 27 iron bars or the like, on both the upper and lower press platens.
13016i8 1 Thus, when the press is in the closed position the space between 2 the working face of the iron bar and the surface of the press 3 platen defines the amplitude of the waveboard.
4 It is to be noted, however, that when utilizing such an assembly, the mat of wafers plus binder in admixture must be 6 placed between a pair of flexible screen members before 7 positioning between the platens. As a result of this provision, 8 it is effectively possible to avoid the displacement or g ~stretching~' of the wafers in the zone between corners of opposed upper and lower bars, which would otherwise take place.
11 The advantages arising from the present invention thus 12 involve a product which can be relatively simply and 13 inexpensively manufactured yet which exhibits marked improvement 14 in performance characteristics.
Broadly stated the invention comprises a board formed 16 of a composite material said board having at least one half wave 17 formed therein wherein the amplitude of the wave is substantially 18 equal to or less than the thickness of said board.
Figure 1 is a comparative illustration of the profiles 21 of sinusoidal corrugated waveboard, low amplitude waveboard and 22 planar waferboard to accompany the panel property values thereof 23 which are detailed in Table I herein.
24 Figure 2 is a perspective view of a finished waveboard panel.
26 Figure 3 is a schematic illustrating the press steps 27 employed in the process of the present invention.
28 Figure 4 is a side-sectional detailing the dimensions ~30~6~8 1 of the board.
2 DESCRIPTION OF THE PREFERRED EM~ODIMENT
3~aving reference to the accompanying drawings there is 4shown at 1 the press system utilized to manufacture the low 5amplitude waveboard.
6More specifically, upper and lower platens 2a and 2b 7respectively, each include a base plate 3.
8A plurality of spaced apart, parallel longitudinally 9extending rectangular bars 4 are affixed to the working surface 10of the base plates 3.
11In order to obtain a low amplitude waveboard of 12thickness "A" and wave-length "B" the platens would be arranged 13as shown in the figures.
14The horizontal platen assemblies are arranged in spaced 15apart opposed relationship as shown in Figure 3. Conventional 16press members (not shown) are connected to the platen assemblies 172, for biasing the latter together in a vertical direction and 18applying pressure thereto.
19As would be evident to one skilled in the art, the 20waveboard may be manufactured form a variety of suitab~e 21materials, exemplary of which would be wood composite materials.
22The process for producing the low amplitude waveboard 23from wood wafers was as follows:
24The furnish could be prepared using various wood 25species. Aspen logs approximately 8" length and 6 - 14" in 26diameter were used. The logs were cleaned, debarked waferized 27and screened in accordance with conventional methods. The strand 28or wafer length could range from 2~ mm to 300 mm, but preferably 13016~8 1 would be 50 mm to 100 mm for the best results. The thickness of 2 the wafers was about 0.75 mm. The width of the strands may range 3 up to 50 mm.
4 The moisture content of the furnish was reduced from the green state to about 5% using commercial dryers. The wafers 6 were screened following drying.
7 At 5~ moisture content, the furnish was blended with 8 about 2~ to 3% by weight of powdered phenol formaldehyde resin 9 and 1~ by weight wax in a drum blender. Wax was utilized to improve the moisture resistance of the panel. ~esin was used as 11 a binder for the wafers.
12 The wafers and wax/resin or binder, in admixture were 13 arranged loosely between two flexible screens to form the mat.
14 Alternatively and advantageously the wafers may be orientated (using methods conventional in the art) parallel to the profile 16 of the wave-front. By arranging the wafers in this manner, I
17 have determined that the bending stiffness of the panel may be 18 approximately doubled, as shown in Table III herebelow.
19 The quantity of wafers and resin used was sufficient to produce a board having a density of 600 - 800 kg/m3.
21 In order to avoid having areas of lower density in the 22 panel in the sone marked "Z", I have determined that it is 23 essential to uniformly spread the mat between flexible screens 24 before placing it between the platens. Suitable screens could be manufactured from such exemplary materials as high tension carbon 26 steel mesh wire screen type #163 supplied by Gerald Daniel & Co.
27 Inc., N.Y.
28 In the press, the mat was subjected simultaneously to 29 high temperature, which cured the resin and to high pressure ~3016~8 l which compressed the mat to its specified thickness. The platen 2 temperature was maintained at 205c.
3 Table I given herebelow provides a comparison of the 4 panel properties of the sinusoidal corrugated waferboard, low amplitude and planar waferboard illustrated in Figure 1. The low 6 amplitude panels were made using the malelfemale press platens 7 illustrated in Figure 3.
g (ControlJ Low Flat Amplitude 11 Panel Propertieswaferboardwaferboard 12 Panel density (kg/m3)665 643 13 Unit panel mass rkg/m2) 7.7 7.6 14 Wavelength (mm) -- 114 Panel depth (mmJ 11.6 25 16 Skin thickness (mmJ 11.6 11.6 17 MC (~) 3.6 3.9 18 Unit max. moment 19 (NmmlmmJ 587 943 Bending stiffness 21 Unit El (Nmm2/mm) 724,000 2,460,000 22 All the panels were prepared in the above example using 23 random oriented flakes. All panels were manufactured using 75 mm 24 long aspen flakes of 0.75 mm thickness. The weight of powdered phenolic resin was 3%.
26 Table II given herebelow shows the panel properties of 130~618 1 two different density low amplitude waveboard panels compared to 2 flat waferboard. The panels were prepared using the press 3 platens and flexible screen system described herein. The wafer 4 orientation was random.
TABLE II
6 (ControlJ Low Low 7 Flat Amplitude Amplitude 8 Panel Properties waferboard waferboard waferboard g Normal High Normal Density Density Density 11 Panel density (kg/m3J665 801 661 12 Unit panel mass (kg/m2J 4.1 5.5 4.0 13 Wavelength (mmJ -- 89 89 14 Panel Depth (mmJ 6.2 12.7 12.7 Skin Thickness (mm) 6.2 6.8 6.1 16 MC (%) 3.3 3.6 4.1 17 Unit max. moment (M maxJ
18 (Load Capacity) (Nmm/mm) 168 368 247 19 Bending stiffness Unit E1 (Nmm2/mm) 96,600 504,000 322,000 21 In Table III herebelow there is provided a comparison 22 between low amplitude waveboard having strongly orientated wafers 23 versus low amplitude waveboard having randomly orientated wafers.
24 By "strongly" orientated wafers is meant that a major portion of the wafers, throughout its thickness, are orientated in one 26 direction, specifically parallel to the major axis of the wave 27 front.
1~10~618 TABLE III
2 Low Arnplitude (Control) 3 Corrugated Flat 4 Panel PropertiesWaferboard Waferboard Wafer Orientation*StrongMedium Random Random 6 Relative to Test 7 Span 8 Panel Density (kg/m3J 644 660 638 642 g Unit Panel Mass (Kg/m2) 4.1 4.1 4.0 4.2 ~avelength (mmJ 89 89 89 __ 11 Panel Depth (mm) 13.1 12.8 12.8 6.5 12 Skin Thickness (mm) 6.4 6.2 6.3 6.5 13 MC (%) 3.9 3.6 4.1 3.4 14 Unit Max. Moment (load Capacity) (Nmm/mm) 16 (M max) 377 346 221 147 17 Bending Stiffness 18 (Nmm2/mm) 641,000 496,000 326,000 94,000 19 Replications (-) 8 4 8 8 *The wafer orientation for each panel was the same in face and 21 core layers unlike that for commercial oriented flat waferboard.
Claims (5)
1. A waveboard panel formed by compression and curing of a mat of wafers and binder in admixture wherein the amplitude of said waves is substantially equal to or less than the thickness of said board, and wherein said amplitude ranges from between about 1/8" to about 1".
2. The panel as set forth in claim 1 wherein said amplitude ranges from between about 1/4" to about 1/2".
3. The panel as set forth in claim 2 wherein said wafers are generally oriented parallel to the axis of the wave front.
4. The panel as set forth in claim 2 wherein said wafers are generally oriented perpendicular to the axis of the wave front.
5. A process for making a low amplitude wafer-board panel comprising:
distributing a mat of loose binder-coated wafers between a pair of flexible screen members and placing the latter between press platens, said platens forming a plurality of spaced elongate rectangular members functional to form a wave in said panel wherein the amplitude of the wave is substantially equal to or less than the thickness of said panel, and wherein said amplitude ranges from between about 1/8" to about 1";
biasing the platens together vertically to compress the mat between the working surfaces of the platens; and curing the resin to thereby provide a low amplitude waveboard panel.
distributing a mat of loose binder-coated wafers between a pair of flexible screen members and placing the latter between press platens, said platens forming a plurality of spaced elongate rectangular members functional to form a wave in said panel wherein the amplitude of the wave is substantially equal to or less than the thickness of said panel, and wherein said amplitude ranges from between about 1/8" to about 1";
biasing the platens together vertically to compress the mat between the working surfaces of the platens; and curing the resin to thereby provide a low amplitude waveboard panel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000602085A CA1301618C (en) | 1989-06-07 | 1989-06-07 | Low amplitude wave-board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000602085A CA1301618C (en) | 1989-06-07 | 1989-06-07 | Low amplitude wave-board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1301618C true CA1301618C (en) | 1992-05-26 |
Family
ID=4140177
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000602085A Expired - Fee Related CA1301618C (en) | 1989-06-07 | 1989-06-07 | Low amplitude wave-board |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1301618C (en) |
-
1989
- 1989-06-07 CA CA000602085A patent/CA1301618C/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |