METHOD FOR MANUFACTURING PANELS

Abstract

A method for manufacturing panels such that the panels are subjected on at least one side to an operation with cutting tools. The position and/or orientation of each panel is determined prior to the operation, and the position and/or orientation of each panel is adjusted prior to the operation and/or the position of the tools is potentially adjusted, such that at least one part of each panel concerned takes a fixed orientation and position in relation to the tools.

Claims

1. A method for machining profiled edge areas on a panel, wherein the panel comprises a substrate and a decorative top layer attached to the substrate, wherein the method comprises: providing the panel having lower edge areas on opposite first and second sides of the panel, said decorative top layer forming the top surface of said lower edge areas; optically determining a position or an orientation of the lower edge areas; adjusting the position or orientation of the panel into a fixed orientation based on the optical determination of the position of the lowered edge areas; and then feeding the panel through a first milling machine in the fixed orientation wherein the fixed orientation is transverse to first milling tools of the milling machine such that the first milling tools remain in position relative to the fixed orientation while the panel is fed through the first milling machine as first and second profiled edge portions are formed along each of the respective lower edge areas; wherein the lowered edge areas are partially removed and at least a portion of each lowered edge area remains at a top edge of the profiled edge portion leading to the top surface of the panel; wherein said lowered edge areas are obtained by a pressing operation, which takes place between two press elements; wherein the substrate comprises thermoplastic material and fillers.

2. The method according to claim 1, wherein the thermoplastic material is polyvinyl chloride.

3. The method according to claim 1, wherein the lower edge areas have a first ascending transition zone extending in a first direction to a top surface of the panel, and a second ascending transition zone spaced apart from the first ascending transition zone and extending in a second direction different from the first direction and to a machinable portion of the panel; optically determining said position or said orientation of the lower edge areas, by determining a position or an orientation of the second ascending transition zone; adjusting the position or orientation of the panel into said fixed orientation based on the first ascending transition zone due to the optical determination of the position of the second ascending transition zone.

4. The method according to claim 1, wherein the decorative top layer extends uninterruptedly from the actual top surface, over the surface of the lower edge area.

5. The method according to claim 1, wherein said first and second profiled edge portions define mechanical coupling parts.

6. The method according to claim 1, wherein said panel is a floor panel.

7. The method according to claim 1, wherein after feeding the panel through the first milling machine, the method comprises the step of: feeding the panel through a second milling machine having second milling tools arranged for forming third and fourth profiled edges portions along third and fourth edges of the panel, the third and fourth edges are located transversely relative to the first and second profiled edge portions.

8. The method according to claim 7, wherein the second milling tools are adjusted relative to the third and fourth edges without changing the fixed orientation of the panel.

9. The method according to claim 8, wherein said panel is rectangular, the first and second profiled edge portions are formed along a long pair of opposite sides of the panel, and the third and fourth profiled edges are formed along a short pair of opposite sides of the panel.

10. The method according to claim 1, wherein during the step of feeding the panel through a first milling machine, the top surface of the panel faces downward.

11. The method according to claim 1, wherein said portion of each lowered edge area that remains at a top edge of the profiled edge portion leading to the top surface of the panel, forms a straight chamfer.

12. The method according to claim 1, wherein said portion of each lowered edge area that remains at a top edge of the profiled edge portion leading to the top surface of the panel, forms a curved chamfer.

13. The method according to claim 1, wherein the decorative top layer comprises a printed plastic film.

14. The method according to claim 1, wherein the decorative top layer comprises a print directly on the substrate.

15. A method for machining profiled edge areas on a panel, wherein the panel comprises a substrate and a decorative top layer attached to the substrate, wherein the method comprises: providing the panel having lower edge areas on opposite first and second sides of the panel, said decorative top layer forming the top surface of said lower edge areas; optically determining a position or an orientation of the lower edge areas; adjusting the position or orientation of the panel into a fixed orientation based on the optical determination of the position of the lowered edge areas; and then feeding the panel through a first milling machine in the fixed orientation wherein the fixed orientation is transverse to first milling tools of the milling machine such that the first milling tools remain in position relative to the fixed orientation while the panel is fed through the first milling machine as first and second profiled edge portions are formed along each of the respective lower edge areas; wherein the lowered edge areas are partially removed and at least a portion of each lowered edge area remains at a top edge of the profiled edge portion leading to the top surface of the panel; wherein said lowered edge areas are obtained by a pressing operation, which takes place between two heated press elements; wherein the substrate comprises thermoplastic material and fillers and wherein the decorative top layer comprises a printed plastic film.

16. The method according to claim 15, wherein after feeding the panel through the first milling machine, the method comprising the step of: feeding the panel through a second milling machine having second milling tools arranged for forming third and fourth profiled edges portions along third and fourth edges of the panel, the third and fourth edges are located transversely relative to the first and second profiled edge portions; wherein the second milling tools are adjusted relative to the third and fourth edges without changing the fixed orientation of the panel; wherein said panel is rectangular, the first and second profiled edge portions are formed along a long pair of opposite sides of the panel, and the third and fourth profiled edges are formed along a short pair of opposite sides of the panel.

17. The method according to claim 16, wherein the lower edge areas have a first ascending transition zone extending in a first direction to a top surface of the panel, and a second ascending transition zone spaced apart from the first ascending transition zone and extending in a second direction different from the first direction and to a machinable portion of the panel; optically determining said position or said orientation of the lower edge areas, by determining a position or an orientation of the second ascending transition zone; adjusting the position or orientation of the panel into said fixed orientation based on the first ascending transition zone due to the optical determination of the position of the second ascending transition zone.

18. The method according to claim 17, wherein during the step of feeding the panel through a first milling machine, the top surface of the panel faces downward.

19. The method according to claim 18, wherein the thermoplastic material is polyvinyl chloride.

20. The method according to claim 19, wherein the decorative top layer extends uninterruptedly from the actual top surface, over the surface of the lower edge area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] With a view to better demonstrating the characteristics of the invention, the following, as an example without any restrictive character, describes some preferred embodiments, with reference to the accompanying drawings, wherein:

[0025] FIG. 1 shows a few steps in a method with the characteristics of the present invention;

[0026] FIGS. 2 and 3 show some preliminary steps to the steps in FIG. 1;

[0027] FIG. 4 shows a cross-section on a larger scale along the IV-IV line shown in FIG. 1;

[0028] FIG. 5 represents on a larger-scale the area identified by F5 in FIG. 4;

[0029] FIG. 6 shows on a larger scale a cross-section of a continuous milling machine as shown in FIG. 1 along line VI-VI; and

[0030] FIG. 7 represents on a larger scale a floor panel realized by the method of the present invention according to the line VII-VII shown in FIG. 1.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0031] FIG. 1 shows a method for manufacturing panels, in this case floor panels 1. The corresponding floor panels 1 are rectangular and oblong and they are subjected on both the long pair of opposite edges 2-3 and the short pair of opposite edges 4-5, to an operation S1-S2 by means of cutting tools 6. As shown, for this purpose two continuous milling machines 7-8 are used, wherein in a first continuous milling machine 7 the two opposite long sides 2-3 are milled, and in a second continuous milling machine 8 the two opposite short sides 4-5 are milled. The relevant operations S1-S2 provide the relevant sides 2-3;4-5 with profiled edge areas 9 which include mechanical coupling means 10, which allow two of these floor panels 1 to be coupled together.

[0032] FIGS. 2 and 3 respectively show that for the manufacturing of the floor panels 1 in FIG. 1, prior to the milling operations S1-S2 larger sheets 11 are pressed by means of a DPL pressing operation S0, and are subdivided into panels 1A to be processed further. The pressing operation S0 takes place between two heated press elements 12 of a so-called short-stroke press or single daylight press. This is a discontinuous heated pressing operation with an opening and closing press. The laminate sheet 11 comprises a substrate 13, preferably MDF or HDF, and an applied decorative top layer 14 made of laminate. The laminate is formed on the basis of melamine resin and, in this case, two sheets of paper 15-16, on the one hand a printed paper sheet 15 and, on the other hand, on top of the printed paper sheet 15 a transparent or translucent sheet of paper 16. The top layer 14 of laminate is obtained on the basis of the pressing operation S0 shown in FIG. 2. Here the paper sheets 15-16 are consolidated together and the existing melamine resin is set. In the same pressing operation S0, the attachment of the top layer 14 to the substrate 13 is obtained. At the bottom of substrate 13, a paper sheet 17, soaked in resin, is attached during the same pressing operation S0 as a balancing layer.

[0033] Obviously, preferably from one single pressed sheet 11, several floor panels 1 or panels 1A to be machined further are formed during a dividing operation as the one shown in FIG. 3. D

[0034] The contours of the profiled edge areas 9 of two finished floor panels 1 which are adjacent in the laminate sheet 11 are shown in dashed line 18. Between these contours lies the so-called technical zone 19, which is a material part 20 of the laminate sheet 11 intended to be removed to obtain the final floor panels 1. The removal of this material part 20 is done in the example by means of the dividing operation, more specifically sawing operation 21, of FIG. 3, and the milling operation S1, in FIG. 1.

[0035] FIGS. 2 and 3 also show that, preferably by means of the same pressing operation S0, the pressed sheet 11 has lower areas 22, which in the final floor panels 1 form the lower edge areas 23. Those lower areas 22 have a first ascending transition zone 24 to the actual upper surface 25 of the panels 1A or floor panels 1. In the example, the lower area 22 shows a second ascending transition zone 26 to the actual edge 27 of the panel 1A to be milled. The second ascending transition zone 26 extends globally parallel to the first ascending transition zone 24. The upper surface area 28 of said technical area 19 is preferably situated for most of it at a level further from the center of the panel 1A than the lowest point 29 of the lower area 22, for instance, at a level that coincides or almost coincides, for instance with a height difference of 0.2 millimeters or less, with the level of the actual top surface 25 of the panel 1A to be machined. That way, a low pressure zone is obtained in the technical zone 19 during the pressing operation S0, and any pressing defects may accumulate there, as further revealed in WO 776 as mentioned in the introduction.

[0036] In the example, the top layer 14 extends uninterruptedly from the actual top surface 25 of the panels 1A or floor panels 1, over the surface of the lower edge area 23, more specifically at least over the surface of the first ascending transition zone 24, to the edge 30 of the top surface 25 of the final floor panel 1. In this case, the top layer 14 is uninterrupted at least as far as the second transition zone 26, at least as far as the part of the technical zone 19, between two adjacent second transition zones 26 or even, as shown here, uninterrupted over at least two to be machined panels 1A adjacent to each other in the laminate plate 11.

[0037] FIG. 1 shows that, both prior to the operation S1 on the long opposite sides 2-3, and prior to operation S2 on the short opposite sides 4-5, the position and orientation of each panel 1A to be milled is determined, by optical techniques, for example, using cameras 31. Preferably, as shown in FIG. 4, the position of the said second transitional zone 26, more specifically starting point 32 or its end point 33, is determined for this purpose.

[0038] Potentially, the position and orientation of the panel 1A to be machined is adjusted prior to the processing operation S1 on the long opposite sides 2-3, as shown in dashed line 34 in FIGS. 1 and 4, in a station 35. This can be done by means of actuators 36 such as servo motors and/or hydraulic and/or pneumatic cylinders. In this case, the adjustment of the position and/or orientation is independent of the cutting operation S1, that is while the panel 1A to be machined does not yet contact the components of the feed-through device 37 of the continuous milling machine 7. After the potential adjustment of the position and/or orientation, the panel 1A to be machined is transferred in the desired position and orientation to the feed-through or transport device 37 of the continuous milling machine 7, wherein the panel 1A is fed through the continuous milling machine 7 in this fixed transverse position in relation to the tools 6 to process the long opposite sides 2-3. Preferably, the positioning and orientation of the panel 1A to be machined is such that said first ascending transition zone 24 takes a fixed orientation and position relative to the said tools 6. The position of the tools 6 in the first continuous milling machine 7 is not adjusted here. Preferably, a profiled edge area 9 is reached as shown in FIG. 5, with a top edge 38 situated in the first ascending transition zone 24.

[0039] Potentially, the position of the milling tools 6 in the continuous milling machine 8 for shaping the profiled edge areas 9 on the short opposite sides 4-5 is adjusted, as shown by the arrows 39, based on the determination of the position and/or orientation of the panel 1A to be machined in the station 40. Preferably, the positioning of the milling tools 6 is such that said first ascending transition zone 24 takes a fixed orientation and position in relation to said tools 6. The position of the panel 1A to be milled is not adjusted here. Preferably, also on the short opposite sides 4-5 a profiled edge area 9 is achieved as shown in FIG. 5, that is with a top edge 38 situated in the first ascending transition zone 24.

[0040] Obviously, the method of the present invention, in the example of the figures, is used to manufacture floor panels 1 which have a lower edge area 23 on both the short opposite sides 4-5 and on the long opposite sides 2-3, and the potential adjustments to the orientation and/or position of the panels 1A to be milled, or of the tools 6, are such that each time the first transition zone 24 extending along the relevant side 2-3;4-5 takes a fixed orientation and position in relation to the relevant tools 6.

[0041] FIG. 5 clearly shows that the operations S1 carried out for the shaping of the profiled edge areas 9 provide for the achievement of, a final edge 37 of the floor panel 1 which intersects with, or a top edge 38 situated in, the first ascending transition zone 24 of the lower lying area 22. Furthermore, it is clear that the performed operation S1 also provides for the removal of said second ascending transition zone 26 from the lower lying area 22. Thus, part of the first ascending transition zone 24 forms a lower edge area 23 at the top edge 38 of the final floor panel 1.

[0042] It is noted that the milling operations S1-S2 in FIG. 1 should preferably be carried out with the top layer 14 facing down, as clearly shown in FIGS. 4, 5 and 6. In the continuous milling machines 7-8 applied here, a conveyor chain 41 and pressure belts 42 are used as a feed-through device 37, wherein the conveyor chain 41 provides the reference height for the positioning of the milling tools 6, and, therefore, the panel 1A is transported clamped between the pressure belts 42 and the conveyor chain 41, with the top layer 14 facing down on the conveyor chain 41.

[0043] FIG. 7 shows a floor panel 1 obtained by the method of the invention. FIG. 7 clearly shows that the floor panel 1 has mechanical coupling means 10 at least on the long pair of sides 2-3 to enable two of these floor panels 1 to be coupled together, where, in the coupled condition, there is a lock between the sides 2-3 concerned, both in a horizontal direction H in the plane of the coupled floor panels 1 and perpendicular to the coupled edges 2-3, and in a vertical direction V perpendicular to the plane of the coupled floor panels 1. They are made as a tongue in groove coupling 43-44 equipped with locking means or locking parts 45, wherein said tongue and groove coupling means 43-44 realizes said vertical lock, while said locking devices or parts 45 are provided for the achievement of said locking device in horizontal direction H. Said coupling means 10 are realized in a one-piece manner in the material of the relevant panel 1A, in this case with the essential components 43-44-45 thereof on the substrate 13. As mentioned, the coupling means 10 are provided by means of a milling operation S1 with rotating milling tools 6. The relevant floor panel 1 is also provided with mechanical coupling means 10 on the not shown short pair of opposite sides 4-5. The mechanical coupling means 10 on the long pair of opposite sides 2-3 allow a coupling by means of a tilting movement W along the respective sides 2-3, as well as, preferably, by means of a horizontal sliding movement S of the sides 2-3 towards each other. On the short pair of opposite sides 4-5, coupling means 10 can be used with equal or similar characteristics. According to another example, the coupling means 10 on the short pair of opposite sides 4-5 allow that they, by means of a downward movement of a male coupling part, for example with a tongue, can be brought into a female coupling part, for example with a groove, wherein in coupled condition a lock is created in said vertical and horizontal directions. This is not shown here.

[0044] Regarding FIG. 1, it is also noted that the station 35 for potentially adjusting the position and/or orientation of the panel 1A to be machined, does so by adjusting the transverse position of the transverse edges. For this purpose, it may for instance be sufficient to use two actuators 36, one active near each transverse edge. Preferably, the station comprises at least two actuators 36, preferably a first one active near a first transverse edge and a second one active near a second transverse edge. In the example shown, at least two actuators 36 are positioned near the first and second transverse edges, and are active on the opposite long edges. Dashed line 46 shows that the station 35 may be equipped with actuators 36 that are active at a position between the actuators active at the transverse edges. Such actuators can minimize any curvature of the panel 1A or the part concerned, for instance a lower area 22, in the longitudinal direction.

[0045] The present invention is by no means limited to the embodiments described above, but similar methods for manufacturing panels may be realized without exceeding the scope of the invention.