WO2012042299A1

WO2012042299A1 - Cutting method for cutting panels and associated machine

Info

Publication number: WO2012042299A1
Application number: PCT/IB2010/054400
Authority: WO
Inventors: Alberto Borsato
Original assignee: Robor S.N.C. Di Borsato Rogerio & Borsato Alberto
Priority date: 2010-09-29
Filing date: 2010-09-29
Publication date: 2012-04-05

Abstract

In order to limit wasted material when cutting mineral wool panels with oriented fibres, a method is proposed for cutting the panel (30) making it into strips, characterised in that the panel is cut in a single stroke along a cutting direction (MC) with a plurality of rectilinear blades (26) arranged airborne at a distance equal to the desired width of the strips. Thinner blades can therefore be used.

Description

"CUTTING METHOD FOR CUTTING PANELS

AND ASSOCIATED MACHINE"

The invention refers to a cutting method for cutting panels and to a machine arranged to carry out the method. Preferably, the method is exploited for the in-line production of oriented-fibre panels , through a plant like that described in the rest of the description. Preferably, the machine is fitted inline in such a plant.

In plants for the in-line production of resistant panels, native oriented- fibre panels are cut to obtain strips, that are then rotated and finally joined. A final composite panel is obtained with fibres oriented perpendicular to the greater surface so as to have greater strength. Concerning this, in WO2010/029587 a complete description of a known production process can be found.

In order to cut the strips, cutting machines are used equipped with either a disk saw, like in WO2003/014489 (ibidem fig. 2, ref. 40), or a band saw like in WO2010/029587 (ibidem ref. 26).

Disk saws have two big problems. In order to pass through the entire thickness of a panel or pack of panels, the disks must have big diameters, which make it necessary for the blades to have a great thickness so as to give them strength and avoid wobbling that causes the cutting to not be parallel. The minimum thickness of the blade - about 3 mm - is translated into removed material. By multiplying this thickness by the number of cuts on a panel (even 20 cuts on a thickness for example of 10 cm) and by the number of panels cut in one year (many millions), an estimation of the enormous waste of raw material can be obtained. For example for panels with dimensions 1000 x 100 x 2400 mm, it can be estimated that in Europe alone about 15*10⁶ panels are cut in one year. The annual wastage is thus 15*10⁶*20*10^" 2,4*3*10^"3 = 216000 m³, an enormous value.

The wastage is even in the form of dust that is very expensive to ecologically dispose of. Moreover, for cutting a panel into strips, a cutting tool, formed by many parallel disks at a set distance from one another, is used. In order to change the dimensions of the strips cut, the cutting tool must be replaced and it is necessary to have many in the shed. All of this is costly in terms of labour and in terms of investments.

Even band saws have the drawback of wastage when cutting lots of raw material. The band saw horizontally cuts an entire pack of stacked panels simultaneously, therefore only by using a very thick band saw an acceptable bending can be ensured, which would otherwise cause curved cuts. The width of the cut consequently remains wide, and leads to the same aforementioned drawbacks as disk saws.

The main object of the invention is to provide a cutting method and a machine for carrying it out that improves this state of affairs. Another object is to solve or minimise the drawback of material wastage when panels are cut, thus decreasing the disposal costs and the impact on the environment.

Such objects are achieved with a method and machine according to the attached claims.

The problem of enormous wasting of material is solved or minimised by cutting (preferably entirely) the panel in a single stroke along a cutting direction with a plurality of rectilinear blades arranged in air at a distance equal to the desired width of the strips. Once the panel is made into strips, these are joined so as to obtain a composite panel.

The availability of rectilinear blades in air for cutting a panel into strips makes it possible to have a thinner blade for each cut, and therefore makes it possible to drastically reduce the width of the cut and the waste produced. By cutting only one, or some, panels at a time, the blade or a portion in air of the blade is shorter, and therefore it vibrates less and the cut, which is more precise, becomes narrower. The smaller the size of the cut ,the smaller the part of panel transformed into dust and the less the amount of wastage to be disposed of. Not only are the costs of disposal and of raw material cut down, but the machine and the plant also ensure a much more ecological operation.

The thickness of the blades, or of a portion of blade acting upon the panel, can for example drop to 0,7÷0.9 mm, with respect to those currently used; the wastage is reduced by at least 70%, with obvious advantages. In the example of before, there would be a saving of about 150000 m³ of mineral wool.

The rectilinear blade portions can be blades with reciprocating movement or segments of band saw, which can belong to a single band saw returned many times or to a plurality of band saws.

The cutting system made up of a series of blade segments that with reciprocating movement cut the strips, is less precise. The problem is that in order to maintain a low tolerance and avoid bending in the cut, the blade must be very short and very taut, therefore the linear stroke of the blade has a limit. Consequently, the cutting teeth of the blade do not come out from the panel and have difficulty in freeing themselves of the removed material, which stays in the cut and reduces the efficiency of the blade. For this reason the preferred shape of the blade is a cutting segment belonging to a band saw. Every band shall each have at least one portion of cutting blade in air (or one cutting portion), adapted for independently cutting different zones of one same panel. In order to obtain maximum reliability and durability, it is avoided for the band saw to have too many curves, for which reason each band saw is preferably used to accomplish a single portion of blade in air. Generally, it is preferable to have n independent, rectilinear blade portions, or n blades, to cut the panel in (n+1) strips.

In order to allow the machine to quickly be configured for each size of strip to be cut, a or each blade, for example a segment of band saw, is movable/shiftable in a controlled manner along a direction that is transverse to the cutting direction, for example through blade-guides that can translate or blade deflectors (pulleys, movable guides, etc.), or by translating a frame that supports the rectilinear blade portion, for example that supports a band saw or a blade actuated with reciprocating movement.

A preferred arrangement of band saws envisages that, with respect to the cutting direction, they are arranged in two lines, and in rows two by two. In such a way, on one same plane that is roughly perpendicular to the cutting direction lie two adjacent band saws that simultaneously cut the panel on two opposite sides, and the longitudinal bulk of the machine are minimised. In any case, the band saws can also be in a single line one behind the other.

By "line" we mean the arrangement of the band-saws one after the other substantially on the same line; i.e. positioned one behind the other. By "row" we mean that they are positioned frontally, i.e. side by side with respect to the feed direction of the panel or to the cutting direction (it depends on the motion status of the panel). By "blade in air" or "portion of blade in air" we mean a blade or cutting segment of a blade that projects straight into the empty space comprised between two support points, so that between said points the panel can pass and be cut. The cutting segment can be a stand-aloneblade or it can belong for example to a band saw or a cutting wire.

As a preferred actuation, preferably a or each band saw is mounted on rotary flywheels pivoted on a frame arch, which ensures stability and resistance to shearing stress to the machine. The segment of band saw that remains exposed in air from the relative frame arch preferably has a length of about 200÷300 mm. This range of values ensures excellent cutting precision and the versatility necessary to cut panels with different thicknesses, even of 200 mm.

Experimentally, it has been noted that there is a good compromise between complexity, cost and excellent traction and durability of the band saw if the band saw is mounted on three flywheels with axes substantially arranged like the vertices of an equilateral triangle.

The machine can advantageously be simplified by mounting the band saw on two return flywheels. The lifetime of the blade can also increase, because the distance between the two parallel segments of band saw, of which one is used to cut the panel, must be spaced apart by at least half the width of the panel. This imposes a minimum diameter on the flywheels, and a maximum curvature on the blade.

In order to improve the cutting precision, the machine can comprise two blade-guides mounted on a frame arch to keep the part in air of the band saw straight and/or taut; preferably, the blade-guides are placed at a relative distance of about 220÷320 mm.

In order to move the cutting segment or portion of a band saw, the blade- guide and/or the frame arch supporting it can be moved. In order to improve the flexibility of the machine with batches of panels to be cut into strips of different widths, a or each frame arch can be movable in a controlled manner along a direction that is transverse to the cutting direction. By adjusting the position of the frame arches and/or of the blade-guides with respect to the panel, the distance between the cuts on the panel can be changed with continuity, and strips with a desired width can be produced.

The position control of the blades or rectilinear blade portions can advantageously occur through dedicated software, which controls relative actuators of the machine. A dedicated program receives, from an interface, the relative distances of the segments - i.e. the width of the strips - set by an operator and then it processes the relative control signals so as to correspondingly position the blades or rectilinear blade portions, thus reducing the set-up time of the plant needed for changing the production.

The concept of the invention covers a machine (see claim 20) that has means or is arranged to receive and actuate the aforementioned blades or rectilinear blade portions. Said blades or rectilinear blade portions can be mounted even subsequently and/or with characteristics (length of the portion, material, etc.) which are each time suitable for the panel to be cut.

The blades or rectilinear blade portions can have any spatial orientation, for example all vertical or all horizontal. In the case of toothed blades or toothed portions of blades, and not wire blade for example, they will all be parallel to one another, with the blade edges facing the same direction. The blade-guides can move independently of one another, and in opposite directions, so as to incline the blade with respect to the vertical. Therefore, the panel can be cut so as to give the strip a shape.

Some variants of preferred embodiments of the inventive concept are defined in the dependent claims.

Further characteristics and advantages of the invention shall become clearer from the description given as an example of a cutting machine exploiting the concept thereof, together with the attached drawings, in which: figure 1 shows a front view of a cutting machine;

figures 2 and 5 show a front view of a variant for the machine of fig. 1 ; figures 3 and 4 schematically show a plan view of constructive variants of the machine of fig. 1.

It should be noted that in the rest of the description and in the figures, same reference numerals indicate parts that are the same.

A cutting machine 10 comprises a base 12 on which a plurality of frame arches (or frames), of which only two are visible in fig. 1 and that are indicated with 20a and 20b, are either linearly movable with position control (see arrow F) or fixed. Except for their orientation, the frame arches are the same as one another, and therefore we shall only describe one of them.

The frame arch 20a comprises a C-shaped or arch-shaped frame 25, with two opposite and spaced apart ends 34a, 34b that are separated by an empty space 32. On the frame arch 20a there are three identical motorised flywheels 22 with rotation axes that are preferably arranged like the vertices of an equilateral triangle. This arrangement reduces the curvature of the band saw.

On the flywheels 22 a band saw 24 is mounted that remains exposed at an segment or portion in air of blade 26 that passes through the empty space 32. The segment 26 is kept inside a cutting plane by two blade-guides 28 arranged at the points where the segment 26 detaches from the facing surfaces of the ends 34a, 34b.

Fig. 4 shows a plan view of the machine 10. As an example only four frame arches 20a-20d have been indicated, and therefore there are four band saws 24. In reality the number can vary, and it is set by the thickness that the cut strips must have in relation to the width of the basic panel. For example, for a panel of 1200 mm cut to obtain strips 100 mm wide, it is necessary for there to be (1200/100-l)=l 1 frame arches.

At the centre of the base 12 there is a roller table with rollers 40 adapted for moving and guiding a panel 30 along a forward direction MC (perpendicular to the sheet in fig. 1).- The rollers 40 either form a sliding plane, like in fig. 1 , or a sliding tunnel, formed by two parallel lines of rollers 40. The rollers 40, however, are spaced apart along the direction MC to allow the insertion of a frame arch. The panel 30 is supported by the series of rollers 40, and in the suspended zones between the rollers 40 it is cut by the band- saws 24 (the rectilinear portions) of the various frame arches.

By looking at fig. 4 the operation of the machine 10 can be appreciated.

The panel 30 is dragged by the rollers 40 along the direction MC and gradually meets the segments 26 of all the band saws of the frame arches 20a- 20d. The segments 26 constitute rectilinear blade portions, which by linearly moving vertically cut the panel 30 along cuts T. When the panel 40 has passed through the line of frame arches 20a-20d it is completely cut into strips.

The width of the strips can be programmed by suitably positioning the frame arches on the base 12 through position controls and/or actuators - see arrow F. The positioning occurs perpendicularly to the feed direction MC of the panel 40, or to the cutting direction if the panel remains still and the frame arches are movable also along the cutting direction. In this way the rectilinear blade segments 26 can be spaced apart up to the desired width of the strips. By suitably varying a or each rectilinear blade segment 26 along a direction that is transverse to the cutting direction MC, the width of the strips can be varied. In addition or as an alternative, the system of Fig. 5 can be used, said figure showing a variant for the movement of the band saw.

Here, a frame arch 60 comprises three identical motorised flywheels 62, on which a band saw 64 with a cutting segment 66 in air is mounted. Differently from the other variants, the segment 66 is adjustable in horizontal position (see arrow J) thanks to the controlled and coordinated positioning of two blade-guides 68, which have the function of tautening the portion of blade 66 and keeping it rectilinear. Therefore, to move the portion 66 with respect to the panel 30, it is sufficient to translate the blade-guides 68 together. For wide movements of the blade-guides 68, when it is not sufficient to strongly tauten the band saw 64, it can be necessary to compensate the length variation thereof. For this purpose at least one of the flywheels 62 can have a rotation axis that can is controllable in position (see arrow G), so as to widen or narrow the ring of the band saw 64 as required.

In general the frame arches can have blade-guides that can be adjusted in addition to being able to be positionable themselves (see arrow F); or the frame arches can be fixed and only have movable blade-guides.

Fig. 3 shows a variant for the arrangement of the frame arches. They, indicated here with AT, are all arranged in line on a common base 90, and can be fixed or positioned as already described for fig. 4. A roller table with rollers 40 is still present between the frame arches AT.

The arrangement of fig. 4 is more compact along the direction MC, that of fig. 3 along the direction F. Each plant is able to exploit one of the two geometries in the best possible way according to the space available.

Fig. 2 shows a variant for the movement of the band saw.

Here a frame arch 80 comprises two identical motorised flywheels 82, on which a band saw 84 is mounted. With only two flywheels the structure is simpler and more cost-effective.

***

Claims

1. Method for cutting an onented-fibre panel (30) for making it into strips, characterised by cutting the panel in a single stroke along a cutting direction (MC) with a plurality of rectilinear blades (26) arranged in air at a distance equal to the desired width of the strips.

2. Method according to claim 1, wherein the panel is cut with a plurality of band saws (24) each having at least one rectilinear blade portion (26) in air adapted for independently cutting a different zone of the panel.

3. Method according to claim 1 or 2, wherein, in order to vary the width of the cut strips, a or each blade or rectilinear blade portion is moved along a direction (F) that is transverse to the cutting direction.

4. Method according to one of the previous claims, wherein a or each blade or portion of blade has a length in air of about 200÷300mm.

5. Cutting machine (10; 50) fitted into a plant for producing panels by joining strips cut from oriented-fibre panels, the machine being adapted for cutting a panel (30) in strips, characterised in that it comprises rectilinear blades (26; 66) arranged in air at a distance equal to the desired width of the strips, so as to cut the entire panel into strips in a single stroke.

6. Machine according to claim 5, wherein a blade is a rectilinear portion (26; 66) in air of a band saw (24; 64).

7. Machine according to claim 5 or 6, comprising a plurality of band saws (24; 64) each comprising a single rectilinear blade portion (26; 66) in air adapted for independently cutting a different zone of a same panel along a common cutting direction (MC).

8. Machine according to one of claims 5 to 7, wherein a or each blade or rectilinear blade portion (26; 66) is movable in a controlled manner along a direction (F) that is transverse to the cutting direction so as to vary the width of the strips.

9. Machine according to any one of the previous claims from 6 to 8, wherein with respect to the cutting direction the band saw are arranged in two lines, and in rows two by two.

10. Machine according to any one of the previous claims 6 to 8, wherein with respect to the cutting direction, the band saw are arranged in succession on a single line.

11. Machine according to any one of the previous claims 6 to 9, wherein a or each band saw is mounted on rotary flywheels (22; 62) pivoted on a frame arch (20a; 60).

12. Machine according to claim 11, configured so that a or each blade or rectilinear blade portion has a length in air of. about 200÷300 mm.

13. Machine according to claim 11 or 12, wherein a or each band saw (24) is mounted on three flywheels (22) with axes arranged substantially like the vertices of an equilateral triangle.

14. Machine according to claim 11 or 12, wherein a or each band saw (84) is mounted on two flywheels (82).

15. Machine according to one of claims 11 to 14, comprising two blade- guides (28; 68) that are mounted on a frame arch to keep the rectilinear blade portion in air of the band saw straight and/or taut.

16. Machine according to claim 15, wherein the blade-guides are positioned at a distance of about 220÷320 mm.

17. Machine according to claim 15 or 16, wherein the blade-guides (66) are able to translate with respect to the frame arch to move the relative cutting blade portion in air of the band saw.

18. Machine according to one of claims 11 to 17, wherein a or each frame arch is movable in a controlled manner along a direction that is transverse to the cutting direction.

19. Machine according to claim 18, wherein the frame arches are movable on a common base or bed (12) that acts as a ground base for the machine.

20. Cutting machine (10; 50) fitted in a plant for producing panels by joining strips cut from oriented-fibre panels, the machine being adapted for cutting a panel in strips, characterised in that it is arranged for receiving and actuating blades or rectilinear blade portions arranged in air at a distance equal to the desired width of the strips, so as to cut the entire panel into strips in a single stroke.

21. Machine according to claim 20, wherein a rectilinear blade portion in air belongs to a band saw (24; 64).

22. Program for a processor, for controlling a machine characterised according to one of the previous claims from 5 to 21, which when it is loaded and started is adapted for

receiving from an operator a value representative of the desired distances between the rectilinear blade portions, and

generating command signals for driving actuators of the machine so as to move the blade portions into the corresponding position.

23. Plant for in-line production of composite panels made up of strips cut from panels and then joined, comprising a cutting machine like according to claims 5 to 21.