EP1880816A2 - Method for moulding an area of derived timber boards and device therefore - Google Patents

Abstract

The method involves heating an area (7) of a derived timber board (1), which is to be molded. The derived timber board is formed under pressure. The heating is carried out by doping the derived timber board with water and water vapour, and by heating the doped area. The doping with water and water vapour takes place for adjusting the surface tension. An independent claim is also included for a device for molding area of a derived timber board.

Description

The invention relates to a method for forming a range of wood-based panels and a device therefor. Such continuous processes and the corresponding devices are used in the manufacture of ceiling, wall or floor panels. As wood-based materials, for example, high-density or medium-density fiberboard are used, in the processing of which the side surfaces are profiled into panels.

The profiling of the side surfaces creates sharp edges that interfere with subsequent processing, or that are undesirable for optical reasons. These sharp-edged sections must either be crushed by means of a material-removing process or smoothed by means of a forming process. The resulting chamfered bevels are usually perceived as visually appealing.

If the bevels are produced by milling, there are disadvantages. On the one hand, the structural connection of the wood-based material is reduced by the engagement of the milling cutter. On the other hand, the exposed base material must subsequently be laboriously sealed against moisture. In addition, the exposed base material has a deviating from the remaining surface of the wood material, in particular of a decorative surface color.

It is therefore increasingly transferred to forming the edges of wood-based panels, remain preserved in the coatings and thus a seal of the deformed area is guaranteed.

Suggestions that eliminate both sharp-edged sections and unwanted ones Form changes can be corrected, z. B. from the DE 103 56 837 known. It is proposed to drive with a heated tool over the areas of the surface to be smoothed or reshaped and to reshape these under pressure. A disadvantage of this type of processing of the surface is the very low heat input per unit time, so that can be achieved with such an arrangement only low operating speeds and low degrees of deformation. An increase in the contact temperature is not unlimited, since it can cause burns at elevated contact temperatures at the contact point of the surface to be reshaped.

The EP 1 086 791 proposes to heat the reshaped area of the wood material and the forming tool with hot air and then to achieve the desired deformation by a relative movement between the workpiece and the tool. A disadvantage of this type of processing of the surface is the very low heat input per unit time, so that can be achieved with such an arrangement only low operating speeds. An increase in the contact temperature is not unlimited, as it can cause burns at too high temperatures. In addition, the device cost is very high, as to avoid heat loss, an enclosure o. Ä. Is provided. It is also to be expected with a very high energy consumption, since the heated air from the smooth workpiece surface reflects rather than absorbed and implemented.

The DE 10 2004 031 057 and the EP 1 621 304 Applicant's are considered to be the closest prior art. There it is proposed to heat the area to be reshaped of the wood material by means of infrared radiation, in order to then achieve the desired transformation by means of a forming tool. Although this continuous process is designed for working speeds of 100 m / min and more. However, it has been found that too much effort to heat up with infrared emitters is necessary, so that at such speeds from an economic point of view, no implementation makes sense.

It is therefore the task of proposing a method and an apparatus for forming areas of a wood-based panel, in which good quality and operating speeds of 100 m / min and more can be achieved under economically acceptable conditions.

To solve this problem, a method for continuous forming of areas of a wood-based panel is proposed in which at least the area to be reshaped of the wood-based panel is doped with water and / or water vapor. Subsequently, the doped region is heated. The forming takes place by means of a forming tool, which acts on the heated area of the wood-based panel.

In the processing of wood-based materials such as MDF and HDF in particular, the moisture content or the removal and absorption of water or steam is critical. Varying moisture levels cause undesirable changes in shape and are therefore rejected by experts. The aim is a uniform, unchanged moisture content. So z. For example, when applying glues, care must always be taken to ensure that only the necessary minimum of water is used in order not to trigger local changes in shape in the area of the order.

Surprisingly, however, doping with water and / or water vapor contributes to enabling forming with a particularly homogeneous and high-quality result. The introduced onto or in the reshaped area water can be heated quickly and contributes by the compared to the wood material very much higher thermal conductivity that even at relatively low energy consumption for heating a uniform and also a deeper than known penetrating into the wood material Temperature increase is enabled.

Even small amounts of water are enough to take advantage of this, which significantly contributes to a higher working speed during forming.
In order to accelerate the heating of the area to be reshaped, according to a preferred embodiment of the method according to the invention, water vapor is introduced onto or into the region of the wood material to be reshaped. Water and steam can also be used in mixture. Water vapor can be produced inexpensively or is available inexpensively and can be used to minimize or to further the energy that must be applied for the heating of the wood material replace.

It has proved to be advantageous according to a further alternative of the method according to the invention, the water and / or the water vapor with means for adjusting the surface tension, also known as wetting or wetting agent, put. In general, these are per se known means for lowering the surface tension, which cause a better wetting of the fiber surface. The water and / or the water vapor penetrate faster and further into the reshaped area of the wood material with the aid of better wetting. This penetrating wetting of the fibers to be reshaped results in a particularly uniform and lasting forming result.

The application or introduction of the water and / or water vapor is possible in a variety and technically simple manner. It may preferably be applied by spraying onto the area to be reshaped, by rolling water, by dipping the wood material, and also by doctoring. Water and / or water vapor are sucked into the wood material by utilizing capillary forces along the fibers and into the fiber walls.

Particularly preferred is the doping of water and / or water vapor in the area to be reshaped of the wood material. The injection allows a three-dimensional distribution of water and / or water vapor on and under the surface of the area of the wood material to be reshaped. This not only transforms the surface itself, but also a three-dimensional area. This allows reshaping of the wood material with reduced force, alternatively a stronger forming, which goes beyond a few tenths of a millimeter and can be up to 1-2 mm. In addition, the result of the forming is particularly uniform.

Doping the area to be reshaped with water and / or water vapor is a crucial key to the accelerated reshaping of wood-based materials. Regardless of the energy or heat source, the heat is transferred more quickly to the surface and into the wood material after doping with water and / or water vapor. A particularly high processing speed is achieved when a High-frequency device is used, which efficiently stimulates the water molecules and thereby generates heat. The use of high-frequency devices is known per se.

In order to make the forming more economical and to ensure a good quality of forming, according to an advantageous embodiment of the method according to the invention, the forming tool can be heated. This minimizes or eliminates a potential temperature gradient between the fibers at the surface of the area to be reshaped and the tool surface. At the same time a possible formation of layers in the reshaped region of the wood material is counteracted, which may u.U. u. U.U. in forming a highly heated wood material with a cold tool. can form on the surface of the wood material.

For wood materials that are formed in continuous processes either at low temperatures or in applications that require extensive transformation of the wood material, for. As in an elaborate edge profiling, a preferred embodiment of the method according to the invention proves to be advantageous. According to the invention, the process for forming a range of wood-based materials is carried out at least twice on the same area of the wood-based material to be reformed. The easiest way to do this is by two inventive devices for forming are arranged one after another and the reshaped wood material passes through these devices.

An alternative embodiment of the method according to the invention is used when the area of the wood material doped with water and / or steam is still sufficiently heated after being processed by a first forming tool. Then, by the action of a second forming tool, the desired contour for the region of the wood material to be reshaped can be achieved.

The inventive method with its above-described alternatives and options is particularly suitable for reshaping the edge regions of wood-based materials. It is particularly focused on the transitions from the top and bottom to the side surfaces. Equally suitable is this method but also for forming of edges at the transition of surfaces resulting from the profiling of wood materials, for example for reshaping edges on wood materials with grooved surfaces.

The method according to the invention is preferably carried out with a device for reshaping a region of wood-based materials which has means for heating a region of wood-based materials and a tool for reshaping regions of a wood-based material. These components are known per se. According to the invention, they are supplemented by means for doping regions of a wood material to be reshaped with water and / or water vapor, wherein the means for heating are arranged so that they act on the doped regions of the wood material to be reshaped, and that the tool for forming on the heated region the reshaped wood material acts.

It is essential for implementing the invention that means for doping the area of the wood material to be reshaped with water and / or water vapor are arranged in front of the means for heating and before the forming tool.

The means for doping may be designed as spraying, rolling, dipping or doctoring means, but also as means for injecting. Spray nozzles, application rollers or squeegees or immersion baths for applying or applying coatings to wood-based materials are quite common. They can be readily modified for the processing of water. Means for injecting water and / or water vapor are preferably used. You can z. B. be formed as a rotating spiked rollers with hollow spines whose spines at least partially penetrate into the region of the wood material to be doped. In this case, water and / or steam are then supplied from the interior of the roller and injected through the cavities in the spikes on or in the regions of the wood material to be doped. By this type of doping a precisely defined amount of water or water vapor can be introduced into the wood material. It is to be regarded as an advantage that the water or water vapor are not applied only to the surface of the wood material.

The improved penetration of the area to be deformed with good heat-conducting water or steam results in a significantly improved deformability of the wood material. This manifests itself in a lower power requirement during forming. The tool must therefore exert less pressure on the wood material to effect a given deformation. Alternatively, larger volumes of wood-based material can be reshaped with the same force as in the prior art. The doping with the undesirable water or water vapor thus causes significant improvements in the forming of wood materials, especially when the penetration of water or water vapor can be used in the wood material.

The advantage of the improved heat conduction and thus the improved plasticization of the wood-based material is used particularly efficiently if a high-frequency device, as described above, is used for heating the wood-based material. The wood-based material is heated as far as water or water vapor has penetrated. This pervasive heating improves the plasticization - and thus the formability - of the wood material so that z. B. edge areas can be better provided with chamfers or curves. It proves to be an advantage for the quality of these transformations when the plasticizing and forming not only takes place on the surface of the wood material.

According to the invention, preferred embodiments of the device either comprise two successively arranged tools, which are connected downstream of the means for doping and the means for heating. Or the device has sequentially at least two times each means for doping, means for heating and means for forming, which passes through the wood material to be formed in the operating state in succession until the transformation is completed. The tools can advantageously be shaped so that they each cause a partial deformation of the wood material.

The tools for forming the wood material are known per se. There are usually rotating rollers whose profile is tuned to the deformation to be generated. The tools can be designed to be heatable. The tools can also be designed to be stationary, depending on the type of deformation that is to be made.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Holzwerkstoffplatte

Fig. 2

eine ausschnittsweise schematische Darstellung eines Holzwerkstoff-Paneels mit erfindungsgemäß umgeformter Kante

Fig. 3

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung

Details of the invention will be explained in more detail with reference to the following embodiments. Show it:

Fig. 1

a schematic representation of a wood-based panel according to the invention

Fig. 2

a fragmentary schematic representation of a wood-based panel with inventively formed edge

Fig. 3

a schematic representation of a device according to the invention

1 shows a schematic representation of a wood-based panel produced according to the invention, here as a floor panel 1, consisting of a support plate 2 with a coating 3.

The carrier plate 2 consists of a high-density fiberboard (HDF) and is cuboidal. The support plate 2 has an upper cover surface 4, one of the upper cover surface 4 oppositely disposed lower support surface 5. Between the upper cover surface 4 and the lower support surface 5 extend opposite side surface pairs 6 and 6 ', which is perpendicular to the top surface 4 and to Support surface 5 are arranged. In each case opposite side surface pairs 6, 6 'have connecting means in the form of groove 8 and spring 9, with which several floor panels 1 can be connected together to form a flat composite, not shown. Both the groove 8 and the spring 9 are each provided with corresponding locking means, not shown, which lock connected floor panels 1 in the vertical and in the horizontal direction. The connecting means groove 8 and spring 9 and the locking means, not shown, are made of wood-based material and are machined out of the support plate 2.

The coating 3 is arranged on the upper cover surface 4 over the entire surface and fixedly connected to the support plate 2. The coating 3 consists either of at least one resin-impregnated paper layer or of at least one color or lacquer coating. The coating 3 has an optically effective decoration, for example a wood grain and, moreover, an abrasion-resistant action which results either from abrasion-resistant particles or from a resistant paint surface.

The edge 7 is uniformly formed over its entire length and forms a chamfer 10. The chamfer 10 is rounded in the illustrated embodiment. Bevel 10 may be shaped uniformly or non-uniformly beyond that shown in FIG. The chamfer 10 may be rounded or square. The shape and size of the chamfer 10 depend on the selected degree of deformation.

FIG. 2 shows an enlarged region of FIG. 1 at the edge 7 of the carrier plate 2. Below the chamfer 10, a compacted region 11 is formed, wherein the compression also depends on the shape and size of the chamfer 10 and on the degree of deformation selected.

FIG. 3 shows a schematic representation of the device 12 according to the invention. The device 12 comprises a roller 13 whose peripheral surface is provided with needles 14. The needles 14 communicate with a conduit 15 which supplies water. After the roller 13, a high-frequency device 16 is arranged, which generates heat in the operating state on the floor panel 1. In the working direction, indicated by an arrow A, after the high-frequency device 16, a forming tool 17 is arranged, whose circumference is profiled. The profile is designed to reflect the contour of the reshaped area. The above-described processing unit roller 13, high-frequency device 16 and forming tool 17 are arranged so that can act on a floor panel 1 that is positioned on a conveyor, not shown, and is guided past these processing units 13, 16 and 17.

In operation, a floor panel 1, which is provided with a sharp-edged profile, formed at the edge 7. The forming takes place by firstly guiding the panel 1 past a rotating roller 13 whose peripheral surface is provided with needles 14. The roller 13 is guided past the panel 1 in such a way that the needles 14 at least partially penetrate into the panel 1. The perforated by the needles 14 portion of the panel 1 is acted upon by a line 15 with water, so that the edge 7 is moistened. The water enters the panel 1 through the perforation created by the needles 14. Capillary forces support this Sucking in the water. The water is warmed to a temperature of 80 ° C. The elevated temperature also helps the water to penetrate.

As a result, the panel 1 is carried out in the working direction A under a high-frequency device 16. This high-frequency device 16 acts on the moistened area of the panel 1. On the way to the high-frequency device 16, the water is at least partially drawn into the panel 1. When passing the high-frequency device 16, the water is heated by the alternating magnetic field, according warms the wood material wherever water has penetrated.

The degree of heating may be predetermined by adjusting the corresponding power of the radio frequency device 16. The heating is very fast, so that the working speed is 100 m / min.

The high-frequency device 16 is followed by the forming tool 17, here designed as a wheel, which acts under pressure on the heated area. The forming takes place only by the brief action of the tool 17, a further fixation of the deformed area is not required.

Typically, the inventive method for forming the edges of wall, ceiling and / or floor panels is used.

Claims (17)

Method for continuously forming a region (7) of a wood-based panel (1) with the steps Heating of the area (7) to be reshaped of the wood material board (1) and - molding the wood-based panel (1) under pressure, characterized in that - The heating by doping of the reshaped wood material plate (19) with water and / or with steam and heating of the doped region is carried out. A method according to claim 1, characterized in that the doping is carried out with water and / or steam, which is mixed with means for adjusting the surface tension. A method according to claim 1, characterized in that the doping is carried out by spraying, rolling, knife coating, dipping and / or injecting water and / or water vapor. A method according to claim 1, characterized in that the heating of the doped region by means of a high-frequency device (16). A method according to claim 1 or claim 4, characterized in that the forming tool (17) is heated during forming. Method according to at least one of the preceding claims, characterized in that the at least one second tool for forming a region (7) of a wood-based panel (1) is used on the same area of the wood-based panel (1) to be reshaped. Method according to at least one of the preceding claims, characterized in that the method for forming a region (7) of a Wood material board (1) at least twice on the same area to be reshaped (7) of the wood-based panel (1) is performed. Method according to at least one of the preceding claims, characterized in that edges (7) of a wood-based material panel (1) are reshaped. Apparatus for continuously forming a range of wood-based panels (1) with - Means (16) for heating a portion (7) of wood-based panels (1) and with - A tool (17) for forming areas of a wood-based panel (1), characterized in that - means (12, 13, 14) for doping of reshaped areas (7) of the wood-based panel (1) with water and / or steam are arranged that - The means (16) are arranged for heating so that they act on the doped regions (7) of the reshaped wood material panel (1), and that - The tool (17) for forming on the heated area (7) of the reshaped wood material board (1) acts. Apparatus according to claim 9, characterized in that the means (12, 13, 14) for doping are designed as spraying, rolling, dipping and / or injecting means. Apparatus according to claim 9, characterized in that the means (16) are designed for heating as a high-frequency heating device. Device according to at least one of claims 9 to 11, characterized in that at least two successively arranged tools (17) are provided for forming. Device according to at least one of claims 9 to 12, characterized in that at least two devices (12) for forming regions (7) of a wood-based panel (1) are provided one behind the other. Wood-based panel, comprising a transformed according to at least one of claims 1 to 8 area (7). The wood-based panel according to claim 14, comprising a deformed region (7) between the top surface (4) and side surface (6, 6 '). Wood material board according to claim 14 or 15, characterized in that the formed area (7) is uniformly or non-uniformly, rounded or ekkig shaped. Wood material board according to at least one of claims 14 to 16, characterized in that below the formed area (7) is a compacted area (11) of the wood-based panel.

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