Process for cutting a honeycomb sheet

Abstract

The invention relates to a method for cutting a honeycomb plate. The honeycomb plate consists of a first sheet (4) held opposite and at a distance from a second sheet (6), by means of a honeycomb structure (8). The cutting method according to the invention implements the following steps: a) making a first cut (14) through the first sheet (4); b) filling the first cut (14) with a filling material (16) in the liquid state, until the filling material is flush with the first sheet, the filling material being capable of subsequently solidifying; c) solidification of the filling material (16) filling the first cut (14); d) making a second cut (18) through the filling material, so as to allow the plate to be separated along the first cut (14). Figure 7

Description

Title of the invention: Method for cutting a honeycomb plate Technical field to which the invention relates

[0001] The present invention relates to a method for cutting a honeycomb plate and, more particularly, to a method for cutting a honeycomb plate composed of at least one synthetic polymer. Technological background

[0002] Honeycomb sheets are appreciated due to their lightness, impact resistance and ability to absorb vibrations, in many sectors such as the automotive industry, construction, packaging and many others.

[0003] Honeycomb sheets are usually composed of an assembly of two thin sheets, separated by a honeycomb-shaped alveolar structure. This structure gives the honeycomb sheets high mechanical strength while making them light and easy to handle.

[0004] However, it has been observed that honeycomb sheets made from synthetic polymers may have disadvantages such as sharp and fragile edges after cutting.

[0005] Another disadvantage is that the cells which open onto a cut edge are liable to fill with an undesired element. For example, at a cut edge, water may enter the cells and thus modify the weight and mechanical properties of the cellular plate as a whole.

[0006] Another disadvantage is that when the alveoli are open at one end, this promotes the proliferation inside the alveolar plate of microorganisms such as bacteria or molds.

[0007] In order to overcome these problems, the implementation of an additional method is known from the state of the art, making it possible to cover the edges of the honeycomb plates with a protective material, such as adhesive tape or a protective film.

[0008] For example, document FR2395823A1 proposes, at the end of a process for cutting a honeycomb sheet, the implementation of an extrusion process to cover the cut edge of said honeycomb sheet with a protective film. The attached [Fig.l] represents the extrusion tool 4 for implementing this solution. The extrusion tool 4 is characterized by a “U” shaped profile, the bottom of which is of sufficient size to accommodate the edge of a honeycomb sheet. Along a longitudinal direction 9, the extrusion tool comprises a knife 5, a window 6, an extrusion opening 7 and then a forming strip 8.

[0009] As illustrated by the attached [Fig.2], a honeycomb plate 13 is introduced into the opening of the extrusion tool 4 in such a way that an edge 12 of the honeycomb plate rests against the forming belt 8. The honeycomb plate is then moved along the forming belt, in the direction indicated by the arrow 9 in [Fig.l], so that the knife 5 can cleanly cut the edge of said plate. The waste from the cutting is evacuated from the tool through the window 6.

[0010] A liquid polymer is at the same time introduced under pressure, through the extrusion orifice 7, so as to fill the cells opening onto the edge of the plate. The polymer 3 is subsequently shaped in contact with the forming strip 8 so as to obtain a protective film 12, homogeneous and smooth at the edge of the plate, as illustrated in [Fig.3].

[0011] The method for sealing cells proposed by document FR2395823A1 has the disadvantage of using a tool that is expensive and complex to use. According to another disadvantage, this method can be implemented only to protect the edges of straight-shaped cell plates.

[0012] The present invention aims to remedy these drawbacks by proposing a method allowing the cutting of a honeycomb plate as well as the protection of its cut edges, which is simpler and more economical to implement, while allowing a greater variety of cutting shapes. Subject of the invention

[0013] For this purpose, the invention proposes a method for cutting a honeycomb plate. The honeycomb plate is composed of a first sheet held opposite and at a distance from a second sheet. The first sheet is held to the second sheet by means of a honeycomb structure.

[0014] The cutting method is remarkable in that the following steps are implemented:

[0015] a) making a first cut through the first sheet;

[0016] b) filling the first cutout with a filling material in the liquid state, until the filling material is flush with the first sheet, the filling material being capable of solidifying subsequently;

[0017] c) solidification of the filling material filling the first cutout;

[0018] d) making a second cut through the filling material, so as to allow the separation of the plate along the first cut.

[0019] At the end of step d), the alveolar plate is therefore cut or pre-cut along the line formed by the second cut and, advantageously, the cells open at the level of the first cut are at least partially filled and / or sealed with the filling material.

[0020] By the term "pre-cut" is meant the fact that the honeycomb plate is more easily separable along the second cut.

[0021] Therefore, the method according to the invention proposes the implementation of a method of cutting and covering the cut edges with a protective film, in this case the filling material, simpler and less expensive compared to the state of the art described above.

[0022] Advantageously, the filling material is configured to close the cells opening along the cutting line, in order to prevent the filling of said cells with an unwanted element, at the end of the cutting method according to the invention.

[0023] According to another advantage, the invention makes it possible to simultaneously protect the edges of the plate delimiting the first cutout.

[0024] According to another embodiment, the first cut made during step a), has a width of between 1 and 20 mm, preferably between 2 mm and 10 mm. The width of the first cut corresponds to the smallest distance between the two edges of the alveolar plate delimiting the first cut.

[0025] According to another embodiment of the invention, during step a), the first cut passes through the second sheet. In other words, the first cut passes right through the honeycomb plate. This embodiment allows the filling material to cover the edges of the second sheet delimiting the first cut. Thus, the covering material protects the edges of the second sheet, in order to prevent a risk of cutting at said edges, when the honeycomb plate is handled after it has been cut.

[0026] According to an alternative embodiment, during step b), the filling material is flush with or partially covers a face of the first sheet facing towards the outside of the honeycomb plate. This embodiment advantageously allows the filling material to cover the edges of the first sheet delimiting the first cut. Thus, the filling material protects the edges of the first sheet, in order to prevent a risk of cutting at said edges, when the honeycomb plate is handled after it has been cut.

[0027] According to another embodiment of the invention, during step d), the second cut passes through the second sheet.

[0028] According to another embodiment, during step a), the first cut extends perpendicularly or substantially perpendicularly to the first sheet.

[0029] Preferably, the first sheet is parallel or substantially parallel to the second sheet of the honeycomb plate.

[0030] According to another embodiment, during step b), the filling material is a thermoplastic polymer. By way of non-limiting example, the thermoplastic polymer may be formed from one of the following materials: polyolefins of PE or PP type, elastomer or a mixture thereof, glue of the “hot melt” type or of the PE or PP type or even based on metallocene.

[0031] According to another embodiment, during step c), the filling material is cooled. This cooling may be of the passive or active type. By "active" is meant the exposure of the filling material to a fluid whose flow is forced by a device, such as a liquid spraying system or an air flow ventilation system, the exposure of the filling material to UV radiation in order to initiate the polymerization of said material or other methods known to those skilled in the art promoting hardening of the filling material.

[0032] According to another embodiment, during step d), the second cut is aligned with the first cut. In other words, the second cut is made so as to overlap the first cut.

[0033] According to another embodiment, during step d), the second cut partially passes through the second sheet, so as to subsequently allow easy separation of the plate along said second cut.

[0034] According to another embodiment, during step d), the second cut passes through the second sheet and opens into the first groove. In other words, the second cut is inscribed in the first cut so that the filling material covers the facing edges which delimit the first cut.

[0035] Preferably, during step d), the second cut passes through the second sheet as well as the filling material, in order to clearly separate the alveolar plate along the first cut.

[0036] According to another embodiment, during step a), the first cut forms on the surface of the first sheet, a line comprising at least one angle and / or a rounding. In other words, the honeycomb plate can be cut according to a complex-shaped outline. The cutting method described above therefore offers greater freedom in the shape of cutting a honeycomb plate.

[0037] It should be noted that the method can be implemented to separate a part or an element of the alveolar plate, along a single separation line of complex shape or not, along which the alveoli are closed.

[0038] According to another embodiment, the alveolar plate is formed from polypropylene or polyethylene or a mixture thereof.

[0039] According to another embodiment, the filling material is of the same nature as the alveolar plate.

[0040] According to another embodiment, the smallest distance between the first sheet and the second sheet of the alveolar plate is between 1 mm and 20 mm, preferably between 2 mm and 15 mm;

[0041] According to another embodiment, the alveolar structure comprises at least one groove, formed by at least one rib or wall perpendicular or substantially perpendicular to the first sheet of the honeycomb plate. Preferably, the groove is composed of several walls extending perpendicularly from the first sheet to the second sheet, and the walls are parallel or substantially parallel to each other.

[0042] According to another embodiment, the alveolar structure can be formed from a thermoformed sheet, so as to form between the first sheet and the second sheet, a bubble structure known to those skilled in the art.

[0043] Optionally, the alveolar plate may comprise one or more intermediate sheets, interposed between the first and second sheets, each intermediate sheet separating a alveolar structure.

[0044] According to another embodiment, during step a) described above, the first cut is made so as to be perpendicular or substantially perpendicular to the walls forming the groove.

[0045] According to another embodiment, the first cut and / or the second cut is carried out using the supply of calories, by a technique based on infrared, ultrasound or vibrations for example, while crushing the cellular material. The cut(s) can also be carried out using a cutting tool, such as a milling cutter or by applying pressure to a cutting tool.

[0046] Of course, the various features, variants and embodiments mentioned above may be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive.

[0047] The invention also relates to a honeycomb plate cut according to one of the methods described above. Description of the figures

[0048] The invention will be better understood, thanks to the following description, which relates to preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, in which:

[0049] [Fig. 1] illustrates a perspective view of an extrusion tool according to the state of the art, intended to implement a method of covering an edge of a honeycomb plate;

[0050] [Fig.2] illustrates a top view of the extrusion tool shown in [Fig.l], used to cover the edge of a honeycomb plate;

[0051] [Fig.3] illustrates a cross-section of the alveolar plate shown in [Fig.2], after passing through the extrusion tool illustrated in [Fig.l];

[0052] [Fig.4] illustrates a cross-section of a honeycomb plate;

[0053] [Fig.5] illustrates a first step of a first cutting process according to the invention, of the alveolar plate visible in [Fig.4], consisting of making a first cut through a first sheet and the alveolar structure of said plate;

[0054] [Fig.6] illustrates a following step of the first method of cutting a honeycomb plate according to the invention, consisting of filling the first cut with a filling material;

[0055] [Fig.7] illustrates a final step of the first process of cutting an al plate cellular plate according to the invention, consisting of making a second cut through a second sheet of the cellular plate and the filling material, so as to allow the cellular plate to be separated into two;

[0056] [Fig.8] illustrates a first step of a second cutting process according to the invention, of the alveolar plate visible in [Fig.4], consisting of making a first cut through a first sheet and a second sheet of the alveolar plate;

[0057] [Fig.9] illustrates a next step of a second method of cutting a plate alveolar according to the invention, consisting of filling the first cutout with a filling material;

[0058] [Fig. 10] illustrates a final step of the second method of cutting an al plate veolar according to the invention, consisting of making a second cut through the filling material, so as to allow the separation in two of the alveolar plate. Detailed description of the invention

[0059] As a reminder, the invention proposes a simpler and more economical method for cutting a honeycomb plate, into more varied shapes, while at the same time protecting the edges formed during cutting.

[0060] [Fig. 4] represents a cross-section of a honeycomb plate 2. The honeycomb plate 2 consists of a first sheet 4 held opposite and at a distance from a second sheet 6, by means of a honeycomb structure 8.

[0061] According to the present example, the first sheet 4 and the second sheet 6 are identical. They are made from one of the following materials: polyolefins such as polypropylene, polyethylene, polycarbonate or a mixture thereof. The thickness of the sheets is between 0.05 mm and 2 mm, preferably between 0.07 mm and 1.3 mm.

[0062] The honeycomb structure 8 is of the same or similar nature as the sheets described above. According to the present example, the honeycomb structure is composed of grooves 10, keeping the second sheet 6 parallel or substantially parallel to the first sheet 4. The greatest distance between the first and second sheets is between 1 mm and 20 mm, preferably between 2 mm and 15 mm

[0063] The grooves 10 are delimited by separation walls 12, extending vertically or substantially vertically from the first sheet 4 to the second sheet 6 of the honeycomb plate. The separation walls 12 are parallel or substantially parallel to each other. According to the present example, the thickness of the separation walls is between 0.01 mm and 2 mm, preferably between 0.05 mm and between 1.3 mm. The smallest distance between two adjacent separation walls is between 1 mm and 15 mm, preferably between 2 mm and 10 mm.

[0064] Preferably, the honeycomb plate 2 is made from polypropylene. The honeycomb plate 2 may be manufactured using an extrusion process.

[0065] [Fig. 5] illustrates the implementation of a first step of a first cutting method according to the invention. During this first step, a first cut 14 is made through the first sheet 4 as well as the honeycomb structure 8 of the honeycomb plate 2.

[0066] Preferably, the first cutout 14 extends perpendicularly or substantially perpendicularly to a large face of the first sheet 4, and the second sheet 6 delimits the bottom of the first cutout 14.

[0067] Preferably, at the level of the first sheet 4 of the honeycomb plate, the first cutout 14 extends at least partly parallel or substantially parallel to the separation walls 12 forming the grooves.

[0068] Of course, the outline of the first cutout 14 at the level of the first sheet is not limited to this single direction, so that the first cutout can also extend perpendicular to the separation walls or form a line of complex shape, namely, a line comprising at least one angle and / or at least one rounding.

[0069] By way of non-limiting example, the first cutout 14 may form on the surface of the first sheet 4, a closed contour in the shape of a polygon or an oval shape.

[0070] [Fig.6] illustrates a second step of the first cutting method according to the invention, consisting of filling the first cut with a filling material 16 in the liquid state. The filling material 16 is poured so as to fill the volume inside the honeycomb plate, into which the first cut opens. Preferably, the filling material is poured until it is flush with an external face of the first sheet 4, facing the outside of the honeycomb plate.

[0071] Preferably, the filling material 16 is a thermoplastic in the liquid state when it is poured into the cup 14. By way of non-limiting example, the filling material 16 may be composed of one of the following materials: polyethylene, polypropylene, metalocene.

[0072] Advantageously, the filling material at a temperature lower than or possibly lower than the melting temperature of the honeycomb plate, so as to preserve the shape of the honeycomb plate when the filling material fills the first cutout 14.

[0073] According to a third step not illustrated, the filling material 16 is solidified. During this third step, the filling material can be cooled passively or actively. By “active”, we mean the exposure of the filling material 16 to a fluid whose flow is forced by a dedicated device, such as a liquid spraying system or an air flow ventilation system or to UV radiation promoting the polymerization of the filling material.

[0074] According to a fourth step illustrated by [Fig.7], a second cut 18 is made through the second sheet 6 as well as the filling material 16, so as to allow a rapid and clean separation of the alveolar plate along the first cut 14, into two separate elements 20. For this, the second cut 18 is aligned with the first cut 14.

[0075] Preferably, as illustrated by [Fig.7], the second cut is made in the first cut 14, so as to allow the filling material to cover the edges of the honeycomb sheet which delimits the first cut. Thus, the filling material protects the edges of the first sheet, in order to prevent a risk of cutting at the level of said edges, when the honeycomb sheet is handled after it has been cut.

[0076] Figures 8 to 10 now illustrate a second embodiment of a method for cutting a honeycomb plate 2 according to the invention. According to this second example, the honeycomb plate is identical or substantially identical to the honeycomb plate described above.

[0077] During a first step illustrated by [Fig.8], a first cut 14 is made through the first sheet 4, the honeycomb structure 8 and the second sheet 6.

[0078] During a step illustrated by [Fig.9], a filling material 16 in the liquid state is poured into the first cutout so as to cover the edges delimiting the first cutout and the edges delimiting the second cutout.

[0079] According to a third step not illustrated, the filling material 16 is solidified as described above.

[0080] During a fourth step illustrated by [Fig. 10], a second cut 18 is made through the filling material 16, so as to allow a clean separation of the alveolar plate along the first cut 14, into two separate elements 20.

[0081] The second cut is made in the first cut 14, so as to allow the filling material to cover the edges of the alveolar plate which delimits the first cut and the second cut. Thus, the filling material protects the edges of the first sheet as well as the edges of the second sheet, in order to prevent a risk of cutting at the said edges, when the honeycomb sheet is handled after it has been cut.

[0082] Advantageously, the cutting methods described above allow, at the same time, the cutting of a honeycomb plate and the sealing of the ends of the cells of the plate which open at the level of the line of the first cut.

[0083] The invention thus proposes the implementation of methods for cutting a honeycomb plate as well as the covering of the edges of the cutout, in a simpler and more economical manner compared to the state of the art, while allowing a greater degree of freedom in the shape of the cutout.

[0084] By way of non-limiting example, the first cut and / or the second cut mentioned above are carried out using one of the following techniques: supply of calories (heating tools, infrared, ultrasound, vibrations) while crushing the cellular material, it can also be carried out using a cutting tool such as a milling cutter or by applying pressure to a cutting tool or even a cutting table

Claims

Claims

1. Method for cutting a honeycomb plate (2), composed of a first sheet (4) held opposite and at a distance from a second sheet (6), by means of a honeycomb structure (8), characterized in that the following steps are implemented: - making a first cut (14) through the first sheet (4); - filling the first cut (14) with a filling material (16) in the liquid state, until the filling material is flush with the first sheet, the filling material being capable of subsequently solidifying; - solidification of the filling material (16) filling the first cut (14); - making a second cut (18) through the filling material, so as to allow the plate to be separated along the first cut (14).

2. Method for cutting a honeycomb plate (2) according to claim 1, characterized in that, during step a), the first cut (18) passes through the second sheet (6).

3. Method for cutting a honeycomb plate (2) according to claim 1, characterized in that during step d), the second cut (18) passes through the second sheet (6).

4. Method for cutting a honeycomb plate (2) according to claim one of claims 1 to 3, characterized in that, during step a), the first cut (14) passes through the honeycomb plate (2) to the second sheet (6).

5. Method for cutting a honeycomb plate (2) according to one of claims 1 to 4, characterized in that, during step b), the filling material (16) is a thermoplastic polymer.

6. Method for cutting a honeycomb plate (2) according to one of claims 1 to 5, characterized in that, during step d), the second cut (18) is aligned with the first cut (14).

7. Method for cutting a honeycomb plate (2) according to one of claims 1 to 6, characterized in that, during step a), the first cut (14) forms on the surface of the first sheet (4), a line comprising at least one angle and / or at least one rounding.

8. Method for cutting a honeycomb plate (2) according to one of the claims- indications 1 to 7, characterized in that the honeycomb plate (2) is formed from polypropylene.

9. Method for cutting a honeycomb plate (2) according to one of claims 1 to 8, characterized in that the smallest distance between the first sheet (4) and the second sheet (6) is between 1 mm and 20 mm.

10. Method for cutting a honeycomb plate (2) according to one of claims 1 to 9, characterized in that the honeycomb structure (8) comprises at least one groove (10), formed by at least one wall perpendicular or substantially perpendicular to the first sheet (4).

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