Systems and Methods for the Manufacture of Vertically Oriented Fluted Multiwalls

Abstract

Methods and machine for manufacturing vertically oriented core of multiwalls and multiwalls comprising such core. Multiwalls or cores of multiwalls with transversely oriented flutes in their core are sliced perpendicularly relative to the axis of rotation of the flutes. The slices are bent relative to the origin multiwall or core, packed together, welded or fused or mechanically pressed to each other and their top and bottom surfaces leveled to provide a vertically oriented shortened flutes that form the core. The top and bottom surfaces of the core are then laminated. Machine configurations are also provided for continuous manufacturing of vertically oriented cores of multiwalls.

Claims

1. A method for manufacturing vertically oriented multiwall core, said method comprising: (a)providing fluted multiwall or fluted core of multiwall comprising at least one array of transversely oriented flutes; (b)providing at least one cutting means configured for slicing said array of transversely oriented flutes of said fluted multiwall or fluted core of multiwall; (c)placing said cutting means in contact with said transversely oriented flutes of said fluted multiwall or fluted core of multiwall at selected distance from first longitudinal edge of at least one surface of said fluted multiwall or fluted core of multiwall; (d)cutting through a selected thickness of said fluted multiwall or fluted core of multiwall with said cutting means; (e)generating a slice of said fluted multiwall or fluted core of multiwall; (f) folding said slice relative said fluted multiwall or fluted core of multiwall or slice previously cut off from said fluted multiwall or fluted core of multiwall; (g)packing the folded slice with previously folded slices; (h)repeating steps (c)-(g) until reaching second longitudinal edge parallel said first longitudinal edge of said fluted multiwall or fluted core of multiwall.

2. The method according to claim 1, further comprising: (i) stabilizing upper and lower surfaces of said vertically oriented multiwall core; and (j) covering said upper and lower surfaces of said vertically oriented multiwall core.

3. The method according to claim 2, wherein said covering comprises: placing laminates on upper and lower surfaces of said slices obtained from cutting said transversely oriented flutes of said fluted multiwall or fluted core of multiwall; applying heating means over said laminates; and heating said laminates, wherein said laminates comprising at least two layers, wherein said layers are distinguished one from the other according to their MFIs, wherein said heating is configured to turn said bottom layer of said laminates to adhesive, said adhesive bonding said laminates to upper and lower surfaces of said slices, wherein WI of said bottom layer is sufficiently low to at least partly melt said bottom layer of said laminates.

4. The method according to claim 3, wherein said upper and lower surfaces of said slices are wavy, indented and/or textured, wherein said adhesive is configured to form mechanical and/or physical bond with said upper and lower surfaces of said slices.

5. The method according to claim 1, wherein folding one slice is done simultaneously with generating second slice.

6. The method according to claim 1, wherein said slice is folded 1800 towards said fluted multiwall provided in stack formation.

7. The method according to claim 1, wherein said slice is folded 900 clockwise or counterclockwise relative a previously cut slice.

8. The method according to claim 1, wherein said cutting is done down to bottom layer of said fluted multiwall.

9. The method according to claim 1, wherein said cutting is done throughout the entire thickness of said fluted multiwall.

10. The method according to claim 1, wherein said at least one cutting means comprises a single cutting means.

11. The method according to claim 1, wherein said at least one cutting means comprises two cutting means, wherein first cutting means is configured to cut through first surface and second cutting means is configured to cut through second surface opposite said first surface of said fluted multiwall or fluted core of multiwall.

12. The method according to claim 1, wherein said cutting means is selected from roller knife, blade knife and cog-wheels comprising blades between adjacent teeth of said cog-wheels.

13. The method according to claim 1, wherein cross section of said transversely oriented flutes is selected from circular, rectangular, pentagonal, hexagonal, octagonal, parallelogram and diamond shapes.

14. The method according to claim 1, wherein said fluted multiwall or fluted core of multiwall comprise a plurality of arrays of transversely oriented flutes.

15. The method according to claim 12, wherein said fluted multiwall or fluted core of multiwall comprise two arrays of hexagonal transversely oriented flutes, wherein one array is layered in gaps between flutes of second array.

16. The method according to claim 12, wherein said fluted multiwall or fluted core of multiwall comprise three arrays comprising pentagonal cross section arrays on top and bottom and hexagonal cross section array in the middle.

17. The method according to claim 1, wherein material from which said fluted multiwall or fluted core of multiwall is made is selected from polypropylene (PP), polyethylene (PE), polyethylenterphthalate (PET), polystyrene (PS) and polycarbonate (PC).

18. The method according to claim 1, wherein said packing is done by mechanically pressing or heat-welding or heat-fusing the slices formed to each other.

19. The method according to claim 2, wherein said stabilizing comprises thermal treatment for leveling said upper and lower surfaces of said vertically oriented core multiwall.

20. The method according to claim 2, wherein said laminating is carried out by heat welding, heat-fusion or gluing.

21. Vertically oriented fluted core of multiwall and multiwall comprising said wall manufactured according to the method as claimed in claim 1.

22. A method for manufacturing vertically oriented multiwall core, said method comprising: (a) providing fluted multiwall or fluted core of multiwall comprising at least one array of transversely oriented flutes; (b) providing two cog-wheels comprising blades between each two adjacent teeth of said cog-wheels, said cog-wheels configured for slicing said array of transversely oriented flutes of said fluted multiwall or fluted core of multiwall; (c) placing said cutting means in contact with at selected distance from first longitudinal edge of at least one surface of said fluted multiwall or fluted core of multiwall; (d) rolling said cog-wheels over said fluted multiwall while cutting through down to bottom layer of said fluted multiwall or fluted core of multiwall with said blades; (e) generating a slice of said fluted multiwall or fluted core of multiwall; (f) folding said slice 1800 in stack formation relative said fluted multiwall or fluted core of multiwall or slice previously cut off from said fluted multiwall or fluted core of multiwall; (g) repeating steps (c)-(f) until reaching second longitudinal edge parallel said first longitudinal edge of said fluted multiwall or fluted core of multiwall (h) packing the folded slices with presses applied to top and bottom surfaces of vertically oriented multiwall formed; (i) stabilizing upper and lower surfaces of said vertically oriented multiwall core; and (j) covering said upper and lower surfaces of said vertically oriented multiwall core.

23. The method according to claim 22, wherein said covering comprises: placing laminates on said upper and lower surfaces of said vertically oriented multiwall core obtained from cutting said transversely oriented flutes of said fluted multiwall or fluted core of multiwall; applying heating means over said laminates; and heating said laminates, wherein said laminates comprising at least two layers, wherein said layers are distinguished one from the other according to their MFIs, wherein said heating is configured to turn said bottom layer of said laminates to adhesive, said adhesive bonding said laminates to upper and lower surfaces of said vertically oriented multiwall core, wherein MFI of said bottom layer is sufficiently low to at least partly melt said bottom layer of said laminates.

24. The method according to claim 23, wherein said upper and lower surfaces of said vertically oriented multiwall core are wavy, indented and/or textured, wherein said adhesive is configured to form mechanical and/or physical bond with said upper and lower surfaces of said vertically oriented multiwall core.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIGS. 1A-C schematically illustrate different perspectives of horizontally fluted multiwall.

[0051] FIGS. 2A-B schematically illustrate first step in a process manufacturing fluted multiwall.

[0052] FIGS. 3A-B schematically illustrate another first step a process of manufacturing vertical fluted multiwall.

[0053] FIGS. 4A-B schematically illustrate second step in a process of manufacturing vertical fluted multiwall.

[0054] FIGS. 5A-B schematically illustrate third step in a process of manufacturing vertical fluted multiwall.

[0055] FIGS. 6A-C schematically illustrate last step in a process of manufacturing vertical fluted multiwall and the multiwall manufactured.

[0056] FIGS. 7A-C schematically illustrate different perspectives of hexagonal fluted multiwall.

[0057] FIGS. 8A-B schematically illustrate first step in a process of manufacturing vertical hexagonal fluted multiwall.

[0058] FIGS. 9A-D schematically illustrate second to last steps in a process for manufacturing vertical hexagonal fluted multiwall.

[0059] FIGS. 10A-C schematically illustrate different perspectives of double-layer hexagonal fluted multiwall.

[0060] FIGS. 11A-C schematically illustrate the steps in a process for manufacturing vertical double-layer hexagonal fluted multiwall.

[0061] FIGS. 12A-C schematically illustrate different perspectives of the vertical double-layer hexagonal fluted multiwall manufactured.

[0062] FIGS. 13A-E schematically illustrate and summarize the steps of manufacturing vertical fluted multiwall.

[0063] FIG. 14 schematically illustrates a particular machine for manufacturing vertical fluted multiwall.

[0064] FIG. 15 illustrates triple layer core of transversely oriented multiwall with combination of cross-sections of its flutes.

[0065] FIG. 16 illustrates a particular procedure for covering the slices.

DETAILED DESCRIPTION OF THE DRAWINGS

[0066] The following describes different aspects of the method and machine of the present invention and in further detail and for demonstration purposes without departing from the scope and spirit of the present invention. It is understood that the configuration(s) and mode(s) of operation described herein do not limit the present invention to the particulars detailed below.

[0067] FIGS. 13A-E summarizes the process for manufacturing vertically oriented core and multiwall comprising it according to the present invention. A fluted core of a multiwall is first provided (FIG. 13A) with a transversely oriented array of flutes, namely the flutes that support the top and bottom skins of a multiwall stretch along its width. The core of the multiwall is vertically cut to selected depth through the thickness of the multiwall core and along its length with a plurality of cuts at selected distance from each other. As illustrated in FIG. 13B, a plurality of cutting means may simultaneously cut through the thickness of the core of a multiwall in parallel lines, where each two adjacent cuts are made from opposite sides to enable the folding step of the slices formed fluent and simultaneous with the cutting step. The third step in the process involves heat treatment of the top and bottom surfaces of the slices (FIG. 13C) to heat- or fuse-weld the slices to each other or press them together and form unified smooth surfaces for laminating the top and bottom skins as illustrated in FIG. 13D. The product of the process, which is vertically oriented core multiwall, is shown in FIG. 13E.

[0068] FIGS. 1 through 5 illustrate the schematics of forming vertically oriented core and multiwall thereof in further detail. In FIGS. 1A-C a transversely oriented core of a multiwall (1) is illustrated in different perspectives. The flutes (2) are perpendicular to the top and bottom skins (3a, 3b), adjacent each other, and extend along the width of the multiwall.

[0069] The first step of converting transversely to vertically oriented core of multiwall can be carried out in two exemplary methods as illustrated in FIGS. 2A-2B and 3A-3B. Knives or blades (4a, 4b) are simultaneously placed in contact with the top and bottom surfaces of the core or skins (3a, 3b) for that matter and at selected distance between their points of contact. The knives/blades (4a, 4b) cut through the depth of the core/multiwall a selected depth (5a), for example, down to a bottom layer of the origin multiwall, that enables folding the slices (5) formed in the next step (shown in FIG. 2B). In one option, after reaching the desired depth, the knives/blades (4a, 4b) extend the cut formed at the point of entry along the length of the core or multiwall. In another option, the blade is at least the width of the width of the origin multiwall, so the slice is formed with one cut. As a result, a slice is cut off from the entire row of flutes (2). The knives/blades (4a, 4b) then define another distance between them that is adjacent the former distance, and repeat the cutting process forming another slice (5). Each slice (5) is folded 90 around the newly formed axis represented by (5a) relative to the original axis of rotation of the flutes, where each two adjacent slices are folded one in clockwise direction, the other in counterclockwise direction in accordion fashion. Alternatively, the slices are folded 180 towards the origin multiwall in stack formation as described above. As shown in FIG. 2B the steps of slicing and folding can be carried out continuously with each other. Namely, the slices formed are folded 90 or 180 while knives/blades (4a, 4b) continue to cut new slices. The particular example in FIG. 2B shows that the core/multiwall advances a selected distance towards the folding area while the knives/blades (4a, 4b) stay in fixed position relative to it. Alternatively, the core/multiwall may be fixed in place, while the knives/blades (4a, 4b) move along its width a selected distance each time. In a third option, both the knives and multiwall or core of multiwall move one relative to the other in opposite directions.

[0070] FIGS. 3A-B exemplify variation of the method of forming a vertically oriented core of multiwall. In this method, the slices (5) are entirely cut off and separated from the core/multiwall (1). Accordingly, only one knife or blade (4a) is required. The slices (5) are collected and packed in vertical position relative to their axis of rotation and top and bottom surfaces of the skins that will cover them. Thermal treatment and lamination follow the cutting and folding steps.

[0071] FIGS. 4A-B illustrate the following step of stabilizing the core of arrays of vertical shortened flutes adjacent each other. Presses (6a, 6b) apply isostatic pressure on the open ends of the slices of flutes (5) from parallel opposite sides, thereby leveling and smoothing the surfaces for the following step of covering or lamination and heat- or fuse-welding adjacent slices to each other or the slices are mechanically pressed to each other.

[0072] FIGS. 5A-B show the final step of laminating the slices (5) according to each of the cutting versions presented in the previous Figs. For each, the lamination or covering is essentially the same, closing the open ends of the slices (5) with laminates (7a, 7b) attached to them with heat-welding, heat-fusion or gluing. The core obtained may then be used for different purposes and uses by overlaying different covers on it.

[0073] FIG. 16 schematically illustrates a particular procedure for covering the slices (5) with covers (7a, 7b). Particularly, covers (7a, 7b) are composed of two layers (a, b) that form an extruded sheet, where each layer has a different MFI (Melt Flow Index) relative to the other layer. Using extrusion to form the covers (7a, 7b) enables the adhesion of the two layers (a, b) to each other. When contacting the covers (7a, 7b) to the outer surfaces of the slices (5) core and applying heat, layer (a), which is in direct contact with the slices (5) melts over their top ends and functions as adhesive to bond the covers (7a, 7b) to the slices (5). Now, due to the difference in MFIs of the two layers (a) and (b), layer (a) absorbs the heat and melts, where layer (b) remains intact and forms the outer surface of the vertical multiwall. The melted layer (a) may bond to the outer surfaces of the slices (5) in any way known for adhesives, for example mechanical by infiltrating into crevices and holes in the surface of the slices (5) and/or increasing friction between the cover and surface of the slices and/or physical by generating physical bonds between the adhesive molecules and the molecules of the material of the slices (5) at their surface.

[0074] The (b/c) indication in FIG. 16 signifies the eventual result, where layer (a) no longer exists in the form of a continuous layer with defined dimensions but rather as adhesive layer that connects between layer (b) that forms the skin of the multiwall structure, and the surface of the slices (5). The structure of the multiwall, thus, is now defined by the slices (5) core and the outer layer (b) of the extruded sheets, i.e., covers (7a, 7b).

[0075] In a particular embodiment, the bottom surface of the extruded sheet, that is the bottom surface of layer (a) that comes in contact with the surfaces of the slices (5), is not smooth. For example, such surface may be wavy, indented and/or textured to match waviness, indentation and/or texture of the surfaces of the slices (5) that result in the process of cutting the transverse flutes to form perpendicular flute core. In such case, layer (a) may better function as adhesive upon melting and optionally slightly pressing, due to the plurality of crevices and holes at the slices surfaces into which the adhesive can infiltrate and form a stronger bond, mechanical and/or physical.

[0076] The vertically oriented multiwall core (1) is shown in different perspectives in FIGS. 6A-C. The slices or arrays (5) of now vertically oriented shortened flutes are packed one next to the other, welded or fused together ordered in place after removing mechanical pressure applied on the slices, and covered with top and bottom covers (7a, 7b). The multiwall core (1) formed is, therefore, obtained in a relatively simple and cost-effective process without complex technologies or machinery.

[0077] Heat may be applied also to relieve tension built in the core as in the cutting and folding process.

[0078] Vertically oriented core multiwall can be essentially done with any shape of flutes and/or any form of packing. FIGS. 7A-9D demonstrate the same process described above for flutes with hexagonal cross section (8a). Here also the array of flutes is sliced to multiple slices. The gap between adjacent flutes (8a) contains a horizontal film (8b) connecting between them, which is cut and separated from the array (8) in the slicing step. The slices (8c) formed may remain connected to each other in an axis of rotation (8d) and rotated 90 clockwise or counterclockwise to form adjacent arrays of shortened vertically oriented hexagons (8c) packed together to form the core of the multiwall (see FIG. 9D). Alternatively, the slices are folded 180 relative to the origin multiwall and packed in stack formation as explained above. Otherwise, they may be completely cut off from each other and then packed in vertical position relative to their axis of rotation. Thermal treatment and lamination with covers (7a, 7b) are then carried out on the top and bottom surfaces.

[0079] Double layer core of hexagonal flutes (9) is demonstrated in FIGS. 10A-C in which the gap in the lower array of hexagonal flutes (9a) is now occupied with a second layer of hexagonal flutes (9b). The process of manufacturing a vertically oriented core of multiwall (1) is illustrated in FIGS. 11A-C and essentially the same as the process shown in FIGS. 2A-5B. This time, however, two layers of hexagonal flutes (9a, 9b) are sliced in each cut, folded 90 (clockwise or counterclockwise) around the axis (9e) formed between adjacent slices to form vertically oriented arrays of shortened hexagonal flutes (9c) or 180 towards the origin multiwall in stack packing formation. The two layers now result in fully packed core without gaps between the shortened hexagonal vertical flutes (see FIGS. 12A-C). The top and bottom surfaces of the double-layer hexagonal flutes core are stabilized and laminated to form the double-layer hexagonal vertical multiwall core (see FIGS. 11B-C).

[0080] FIG. 15 shows a triple layer core of multiwall with alternating layers of pentagonal and hexagonal flutes. Essentially, the arrangement or layer number of flutes in the core does not affect the method of the present invention for manufacturing multiwalls with vertically oriented core. Therefore, any number of layers of flutes with varying cross sections is well within the scope of the present invention.

[0081] FIG. 14 schematically illustrates front view of particular machine for manufacturing vertically oriented core multiwalls. Two cog-wheels (10a, 10b) are placed beside each other, with their axes or rotation parallel one to the other. Blades (11) are inserted between adjacent teeth of each cog-wheel to cut slices from multiwalls (1) with transversely oriented core that pass between the wheels (10a, 10b). The slices leaving the space between the two wheels (10a, 10b) are then folded 90 or 180 back on the origin multiwall, and processed further with thermal treatment and lamination (12).

[0082] It should be noted, that the cross sectional shapes of the flutes described above and illustrated in the accompanying drawings are only examples of the possible shapes of flutes that may be used to form vertically oriented flute core. Therefore, rectangular, circular, parallelogram, octagonal and diamond shapes are other examples that may be used to manufacture vertically oriented cores of multiwalls. Further, transversely oriented cores with more than one layer may be used to manufacture the vertically oriented core of multiwall.

[0083] Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.