Method for cutting honeycomb plate

Abstract

The invention relates to a method for cutting a honeycomb panel. The honeycomb panel 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 involves the following steps: a) making a first cut (14) through the first sheet (4); b) filling the first cut (14) with a filler material (16) in a liquid state until the filler material is flush with the first sheet, the filler material being capable of subsequently solidifying; c) solidifying the filler material (16) filling the first cut (14); d) making a second cut (18) through the filler material, so as to allow separation of the panel along the first cut (14).

Description

Technical field to which the invention relates

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

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

[0003] Honeycomb panels are typically composed of two thin sheets sandwiched together by a honeycomb-like structure. This structure gives the panels high mechanical strength while making them lightweight and easy to handle.

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

[0005] Another drawback is that the cells opening onto a cut edge are susceptible to filling with unwanted elements. For example, water can enter the cells at a cut edge, altering the weight and mechanical properties of the entire honeycomb panel.

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

[0007] To remedy these problems, it is known from the prior art to implement an additional process, allowing the edges of the honeycomb panels to be covered with a protective material, such as adhesive tape or a protective film.

[0008] For example, document FR2395823A1 proposes, following a cutting process for a honeycomb panel, the implementation of an extrusion process to cover the cut edge of said honeycomb panel with a protective film. figure 1 The attached diagram shows the extrusion tool 4 for implementing this solution. The extrusion tool 4 is characterized by a U-shaped profile, the base of which is large enough to accommodate the edge of a honeycomb plate. Along a longitudinal direction 9, the extrusion tool comprises a cutter 5, a window 6, an extrusion opening 7, and a forming strip 8.

[0009] As illustrated by the figure 2attached, a honeycomb plate 13 is inserted into the opening of the extrusion tool 4 such that an edge 12 of the honeycomb plate bears against the forming strip 8. The honeycomb plate is then moved along the forming strip, in the direction indicated by the arrow 9 on the figure 1 so that the knife 5 can cleanly cut the edge of said plate. The cutting waste is evacuated from the tool through the window 6.

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

[0011] The socket sealing method proposed in document FR2395823A1 has the disadvantage of requiring a costly and complex tool. Another drawback is that this method can only be used to protect the edges of straight-shaped sockets.

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

[0013] To this end, the invention proposes a method for cutting a honeycomb sheet. The honeycomb sheet 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 process is remarkable in that the following steps are implemented: a) making a first cut through the first sheet; b) filling the first cut with a liquid filling material until the filling material is flush with the first sheet, the filling material being capable of solidifying subsequently; c) solidification of the filling material filling the first cut; d) making a second cut through the filling material, so as to allow separation of the plate along the first cut.

[0015] At the end of step d), the honeycomb plate is therefore cut or pre-cut along the line formed by the second cut and, advantageously, the cells opened at the level of the first cut are at least partially filled and / or sealed by the filling material.

[0016] The term "pre-cut" means that the alveolar plate is more easily separable along the second cut.

[0017] Therefore, the process according to the invention proposes the implementation of a cutting and covering process of the cut edges, with a protective film, in this case the filling material, simpler and less expensive compared to the prior art described above.

[0018] Advantageously, the filling material is configured to seal the openings along the cutting line, in order to prevent the filling of said openings by an unwanted element, at the end of the cutting process according to the invention.

[0019] According to another advantage, the invention makes it possible to simultaneously protect the edges of the plate delimiting the first cut.

[0020] According to another embodiment, the first cut made in 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 honeycomb panel delimiting the first cut.

[0021] According to another embodiment of the invention, in step a), the first cut passes through the second sheet. In other words, the first cut goes completely through the honeycomb panel. This embodiment allows the filler material to cover the edges of the second sheet that define the first cut. Thus, the covering material protects the edges of the second sheet, preventing the risk of cuts at said edges when the honeycomb panel is handled after it has been cut.

[0022] According to one embodiment, in step b), the filler material is flush with or partially overlaps one face of the first sheet oriented towards the outside of the multi-wall panel. This embodiment advantageously allows the filler material to cover the edges of the first sheet defining the first cut. Thus, the filler material protects the edges of the first sheet, preventing the risk of cuts at these edges when the multi-wall panel is handled after it has been cut.

[0023] According to another embodiment of the invention, in step d), the second cut passes through the second sheet.

[0024] According to another embodiment, in step a), the first cut extends perpendicularly or substantially perpendicularly to the first sheet.

[0025] Preferably, the first sheet is parallel or substantially parallel to the second sheet of the alveolar plate.

[0026] According to another embodiment, in step b), the filling material is a thermoplastic polymer. By way of non-limiting example, the thermoplastic polymer can be formed from one of the following materials: PE or PP type polyolefins, elastomer or a mixture thereof, hot melt type adhesive or PE or PP type adhesive or metallocene-based adhesive.

[0027] According to another embodiment, in step c), the filler material is cooled. This cooling can be passive or active. By "active" is meant the exposure of the filler material to a fluid whose flow is forced by a device, such as a liquid spray system or an airflow ventilation system, the exposure of the filler material to UV radiation in order to initiate the polymerization of said material, or other methods known to those skilled in the art that promote the hardening of the filler material.

[0028] According to another embodiment, in 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.

[0029] According to another embodiment, in step d), the second cut partially passes through the second sheet, so as to allow later easy separation of the plate along said second cut.

[0030] According to another embodiment, in step d), the second cut passes through the second sheet and opens into the first groove. In other words, the second cut is inscribed within the first cut so that the filler material covers the opposite edges that define the first cut.

[0031] Preferably, during step d), the second cut goes through the second sheet as well as the filling material, in order to clearly separate the honeycomb plate along the first cut.

[0032] According to another embodiment, in step a), the first cut forms a line on the surface of the first sheet, including at least one angle and / or curve. In other words, the honeycomb panel can be cut along a complex shape. The cutting process described above therefore offers greater freedom in the shape of the honeycomb panel.

[0033] It should be noted that the process can be implemented to separate a part or element of the alveolar plate, along a single separation line of complex or simple shape, along which the alveoli are sealed.

[0034] According to another embodiment, the honeycomb plate is formed from polypropylene or polyethylene or a mixture thereof.

[0035] According to another embodiment, the filling material is of the same nature as the alveolar plate.

[0036] According to another embodiment, the smallest distance between the first and second sheets of the alveolar plate is between 1 mm and 20 mm, preferably between 2 mm and 15 mm;

[0037] In another embodiment, the honeycomb 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.

[0038] 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.

[0039] Optionally, the alveolar plate may include one or more intermediate sheets, interposed between the first and second sheets, each intermediate sheet separating an alveolar structure.

[0040] 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.

[0041] In another embodiment, the first and / or second cut is made using heat input, for example by a technique based on infrared, ultrasound, or vibration, while simultaneously crushing the alveolar material. The cut(s) can also be made using a cutting tool, such as a milling cutter, or by applying pressure to a sharp tool.

[0042] Of course, the different characteristics, variants and forms of realization mentioned above can be associated with each other in various combinations, insofar as they are not incompatible or exclusive of each other.

[0043] The invention also relates to a honeycomb plate cut according to one of the processes described above. Description of the figures

[0044] The invention will be better understood from the following description, which relates to preferred embodiments, given by way of non-limiting examples, and explained with reference to the accompanying schematic drawings, in which: [ Fig. 1 ] illustrates a perspective view of a state-of-the-art extrusion tool designed to implement a process for covering the edge of a honeycomb plate; [ Fig. 2 ] illustrates a top view of the extrusion tool represented by the figure 1, used to cover the edge of a cellular plate; [ Fig. 3 ] illustrates a cross-section of the alveolar plate shown on the figure 2 , after passing through the extrusion tool illustrated by the figure 1 ; Fig. 4 ] illustrates a cross-section of an alveolar plate; [ Fig. 5 ] illustrates a first step of a first cutting process according to the invention, of the alveolar plate visible on the figure 4 , consisting of making an initial cut through a first sheet and the honeycomb structure of said plate; Fig. 6 ] illustrates a subsequent step of the first method for cutting a honeycomb panel according to the invention, consisting of filling the first cut with a filling material; [ Fig. 7] illustrates a final step of the first method for cutting a honeycomb panel according to the invention, consisting of making a second cut through a second sheet of the honeycomb panel and the filling material, so as to allow the honeycomb panel to be separated into two; [ Fig. 8 ] illustrates a first step of a second cutting process according to the invention, of the alveolar plate visible on the figure 4 , consisting of making a first cut through a first sheet and a second sheet of the honeycomb plate; [ Fig. 9 ] illustrates a subsequent step of a second method for cutting a honeycomb panel according to the invention, consisting of filling the first cutout with a filling material; [ Fig. 10] illustrates a final step of the second method of cutting a honeycomb plate according to the invention, consisting of making a second cut through the filling material, so as to allow the honeycomb plate to be separated into two. Detailed description of the invention

[0045] As a reminder, the invention proposes a simpler and more economical method for cutting a honeycomb plate into more varied shapes, while also protecting the edges formed during cutting.

[0046] There figure 4 represents a cross-section of an alveolar plate 2. The alveolar plate 2 consists of a first sheet 4 held opposite and at a distance from a second sheet 6, by means of an alveolar structure 8.

[0047] In this 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.

[0048] The honeycomb structure 8 is identical or similar in nature to the sheets described above. According to the present example, the honeycomb structure consists of grooves 10, holding 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.

[0049] The grooves 10 are delimited by separating walls 12, extending vertically or substantially vertically from the first sheet 4 to the second sheet 6 of the honeycomb panel. The separating walls 12 are parallel or substantially parallel to each other. In this example, the thickness of the separating walls is between 0.01 mm and 2 mm, preferably between 0.05 mm and 1.3 mm. The smallest distance between two adjacent separating walls is between 1 mm and 15 mm, preferably between 2 mm and 10 mm.

[0050] Preferably, the honeycomb panel 2 is made from polypropylene. The honeycomb panel 2 can be manufactured using an extrusion process.

[0051] There figure 5illustrates the implementation of a first step of a first cutting process 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.

[0052] Preferably, the first cut 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 cut 14.

[0053] Preferably, at the level of the first sheet 4 of the alveolar plate, the first cut 14 extends at least partly parallel or substantially parallel to the separating walls 12 forming the grooves.

[0054] Of course, the path of the first cut 14 at the level of the first sheet is not limited to this single direction, so that the first cut can also extend perpendicularly to the separating walls or form a path of complex shape, namely, a path including at least one angle and / or at least one curve.

[0055] As a non-limiting example, the first cut 14 can form on the surface of the first sheet 4, a closed contour in the shape of a polygon or an oval.

[0056] There figure 6This illustrates a second step of the first cutting process according to the invention, consisting of filling the first cutout with a liquid filler material 16. The filler material 16 is poured so as to fill the volume inside the honeycomb panel, into which the first cutout opens. Preferably, the filler material is poured until it reaches the level of an external face of the first sheet 4, oriented towards the outside of the honeycomb panel.

[0057] Preferably, the filling material 16 is a thermoplastic in the liquid state when 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.

[0058] Advantageously, the filling material at a temperature lower or substantially 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 cut 14.

[0059] According to a third, unillustrated step, the filler material 16 is solidified. During this third step, the filler material can be cooled passively or actively. "Active" means exposing the filler material 16 to a fluid whose flow is forced by a dedicated device, such as a liquid spray system or an airflow ventilation system, or to UV radiation that promotes the polymerization of the filler material.

[0060] According to a fourth step illustrated by the figure 7, a second cut 18 is made through the second sheet 6 as well as the filling material 16, so as to allow a quick and clean separation of the alveolar plate along the first cut 14, into two distinct elements 20. For this, the second cut 18 is aligned with the first cut 14.

[0061] Preferably, as illustrated by the figure 7 The second cut is made within the first cut (14), allowing the filler material to cover the edges of the honeycomb panel that defines the first cut. This way, the filler material protects the edges of the first sheet, preventing cuts at those edges when the honeycomb panel is handled after it has been cut.

[0062] THE figures 8 to 10now 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.

[0063] In a first stage illustrated by the figure 8 , a first cut 14 is made through the first sheet 4, the alveolar structure 8 and the second sheet 6.

[0064] During a stage illustrated by the figure 9 , a liquid filling material 16 is poured into the first cut so as to cover the edges delimiting the first cut and the edges delimiting the second cut.

[0065] According to a third, unillustrated step, the filling material 16 is solidified as described above.

[0066] During a fourth stage illustrated by the Figure 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 distinct elements 20.

[0067] The second cut is made within the first cut (14), allowing the filler material to cover the edges of the honeycomb panel that separates the first and second cuts. This way, the filler material protects the edges of both the first and second sheets, preventing cuts at these edges when the honeycomb panel is handled after being cut.

[0068] Advantageously, the cutting processes described above allow, at the same time, the cutting of a honeycomb plate and the sealing of the ends of the plate's cells which open at the level of the line of the first cut.

[0069] The invention thus proposes the implementation of cutting processes for a honeycomb plate and the covering of the edges of the cut, in a simpler and more economical way compared to the prior art, while allowing a greater degree of freedom in the shape of the cut.

[0070] 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: applying heat (heating tools, infrared, ultrasound, vibrations) while crushing the alveolar 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 a cutting table.

Claims

1. Method for cutting a honeycomb plate (2) composed of a first sheet (4) held in front of and at a distance from a second sheet (6) by means of a honeycomb structure (8), characterized in that the following steps are performed: - doing a first cut (14) through the first sheet (4); - filling the first cut (14) with a filling material (16) which is liquid, until the filling material reaches the first sheet, the filing material being able to solidify later on; - solidifying of the filling material (16) filling the first cut (14); - doing a second cut (18) through the filling material so as to allow the separation of the plate along the first cut (14).

2. Method for cutting a honeycomb plate (2) according to claim 1, characterized in that, at step a), the first cut (14) goes through the second sheet (6).

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

4. Method for cutting a honeycomb plate (2) according to anyone of claims 1 to 3, characterized in that, at step a), the first cut (14) goes through the honeycomb plate (2) up to the second sheet (6).

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

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

7. Method for cutting a honeycomb plate (2) according to anyone of claims 1 to 6, characterized in that, at 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 anyone of claims 1 to 7, characterized in that the honeycomb plate (2) is formed from polypropylene.

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

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