EP0744260A1 - Method and apparatus for continuous machining of porous wooden work pieces, and in particular the edges - Google Patents

Abstract

Each workpiece (1) is held by a clamp and undergoes treatment from the successive units of a grinder and polisher (B,C), an applicator (D) for the coating material (3), and a hot smoother (D). The grinder and/or polisher is profiled. The applicator is in the form of a nozzle, roller (2), transfer belt. The hot smoother consists of groups of heated doctor blade elements (4) positioned around the profiled edge (5) of the workpiece being treated.

Description

The invention relates to a method and a device for continuous processing of essentially flat or strip-shaped workpieces on open-pore wood materials and the like.

If plate-shaped, strip-shaped or similar workpieces made of open-pore wood-based materials, such as chipboard, or other open-pore materials are processed in the edge area, the edge has to be tempered in many applications because the open-pore cut surfaces of the workpieces have insufficient surface quality and strength. Various methods have therefore been used Coating of open-pore edges, for example chipboard, has been developed.

For example, the patent specification DD-PS 29 705 describes a method for solidifying particularly stressed areas in the edge area of porous plates, in particular chipboard. The particle board is clamped in a trough which is sealed around the edge region of the workpiece to be tempered, and a solidifying agent in the form of an adhesive or mixture of adhesives is pressed under pressure into the edge of the workpiece via the sealed trough. The adhesive mixture must then be cured.

Likewise, a device is explained in German patent DE 16 53 240 C3, with which porous chipboard panels can be solidified in the edge area to increase, for example, the screw strength. Here, a solidifying agent is pressed from a press-in chamber into the porous edge of the workpiece under pressure.

German patent DE 40 28 166 C2 also proposes a method and a device for strengthening chipboard in the edge area, in which a strengthening agent is injected into the edge area by means of individual nozzles.

Furthermore, the German patent application DE-OS 23 61 434 proposes a method to achieve a smooth finish without pores on the rough and grained cut surface of a plate-shaped workpiece made of pressed wood, plywood or the like. A layer of plastic, polyurethane or synthetic resin is applied to the edge with pores in order to close the pores and to structurally strengthen them. When the sealing material is applied mechanically, the material is injected into Shapes with the contour of the workpiece are proposed. After the applied sealing material has dried or hardened, it is ground or smoothed. This method is intended to obtain board materials with solidified and smooth edges without the use of possibly profiled edge timbers, veneer sheet materials and the like.

However, the methods described above all require very complex devices, such as press-fit chambers or troughs, in which the plate-shaped workpieces with the edge to be tempered have to be firmly clamped. After the hardening agent has been pressed into the edge of the workpiece, the workpiece must be removed from the chamber or trough in order to further process the hardened edge on another machine if necessary after the required curing or drying time.

Another remuneration procedure is explained in German publication DE 24 33 476 B2. It is proposed there to first glue a prefabricated intermediate layer made of a cellulose material onto the porous cut edge, which can be pulled off a roll, in order to then be able to glue this intermediate layer with a prefabricated decorative layer. However, this method requires a high manufacturing and material expenditure for the intermediate layer and an additional glue layer is required. The intermediate layer must also be of sufficient thickness so that it cannot sink into the pores at the cutting edge of the workpiece.

It is therefore the technical problem underlying the invention to create a method and an associated device with which a comparatively simple and continuous processing and tempering of open-pore wood materials and the like in the edge area is possible.

According to the invention, this technical problem is solved by a method having the features of patent claim 1 and by an apparatus for carrying out the method having the features of patent claim 10.

According to the invention, continuous processing is provided in the edge area of flat, strip-shaped or similar workpieces made of open-pore wood-based materials and the like, in which one workpiece pass, i.e. with the same workpiece clamping, machining of the workpiece in the edge area by milling and / or grinding, subsequent application of a hot coating compound to the edge area and subsequent hot filling of the applied coating compound. Hot filling ensures that the applied coating compound penetrates evenly into the pores on the edge of the workpiece. Furthermore, the hot filler minimizes the material consumption of the coating compound to be applied and the surface that the workpiece edge has after passing through the hot filler step is already of comparatively high quality, i.e. comparatively smooth.

In one embodiment of the method according to the invention, the application and hot filling of the coating compound is repeated one or more times during the run. In other words, with the same clamping of the workpiece, the coating compound is gradually applied and hot-leveled. By repeated application and hot filling of the coating compound, this processing step can be divided into a pre-coating and a finished coating, for example.

Preferably, the hot filling of the coating compound is followed by a grinding step, e.g. a fine grinding. As a result, the surface of the coated edge is smoothed further and any protrusions of the applied coating compound are eliminated. If the coating compound is applied and hot-filled in stages, each hot-filling step can be followed by a grinding processing step.

Another embodiment of the method according to the invention consists in additionally applying a second remuneration component to the remuneration composition. This second compensation component, which is applied to the optionally ground compensation compound, can be a compensation compound similar to the first compensation compound, but with a different composition, or it can be a lacquer or the like. A differently composed coating compound could, for example, contain color pigments in order to color the outermost coating layer accordingly, while the surface quality can be additionally improved, for example, with a lacquer.

If no flat edges of the workpiece are desired, but profiled, e.g. rounded edges are desired, it is expedient according to the invention to carry out the machining step of milling and / or grinding as profile milling and / or profile grinding. In this way, the profiling and the tempering of the workpiece in the edge region can take place in succession in the same workpiece pass with the same workpiece clamping.

In a further embodiment of the method according to the invention, as a further processing step of the workpiece that follows in the course of a pass, a paint application is carried out provided, which is followed by drying with ultraviolet radiation and grinding. Thus, in the method according to the invention, the profiling, the tempering, optionally with fine grinding, and also a coating can take place in the same workpiece pass.

A further advantageous embodiment of the method according to the invention consists in connecting a hot stamping as a further processing step during the run, in which, for example, a thin decorative paper film is stamped on. Hot stamping can, for example, directly follow the processing step of tempering, or else the processing step of painting. In a further preferred embodiment of the method, gluing with a coating material, e.g. a thin decorative paper. As with hot stamping, the gluing process step can either follow the tempering step or the varnishing step.

According to the invention, the edge region can thus be machined in a continuous pass through the workpiece while the workpiece clamping remains the same, from profiling and tempering to painting and / or hot stamping or gluing with a coating material.

In the process according to the invention, it is advantageous to use a thermoplastic composition, a thermosetting composition or a thermoplastic composition which cures to form a thermosetting composition. For example, it can be a moisture-crosslinking polyurethane system. The mass used should preferably change from a hot phase to a cold phase within a relatively narrow temperature range, in such a way that the coating mass is in its Hot phase is easy to spread and can be applied to the edge area in a continuous pass and can be filled in hot, and that the coating compound then cools down by a comparatively small temperature difference, i.e. after a comparatively short distance in the workpiece pass, in which it reaches its cold phase can already be subjected to further processing steps, for example fine grinding. Thus, the processing steps of profiling, tempering and painting and / or hot stamping or gluing can be connected in series with a coating material over a short passage of the workpiece.

The method according to the invention thus enables complete machining in the edge region of workpieces made of open-pore wood-based materials and the like with one workpiece clamping in one pass.

A device according to the invention for carrying out the method according to claim 1 has a clamping device which holds the respective workpiece during the passage, and processing stations which are arranged one behind the other for continuous processing, namely a milling and / or grinding station, an application station for the coating compound and a hot filler station. In an expedient embodiment of the invention, the milling and / or grinding station is designed as a profile milling and / or profile grinding station if the workpiece is to be given a profiled edge surface rather than a flat one.

According to the invention, it is favorable to design the application station for the coating compound as a nozzle, roller, transfer belt application unit or the like. Accordingly, the hot coating compound is continuously applied to the nozzle either by nozzles, by an application roller or by a transfer belt Edge area applied. Since with the application station, in contrast to conventional devices that press a solidifying agent with complex injection chambers into the edge under pressure under pressure, the hot coating compound is only applied to the edge area, the application station can be made very compact and comparatively simple and work in a continuous process.

In a preferred embodiment of the invention, the hot filler station consists of heated doctor elements which are arranged around the edge profile of the workpiece to be machined. The heated doctor elements are so spatially grouped around the edge profile to be machined that the previously applied hot coating compound is pressed evenly into the pores of the edge area by the doctor elements as it passes through the workpiece. In a favorable embodiment, several groups of doctor elements arranged around the edge profile of the workpiece to be machined are connected in series in the hot filler station. This results in a gradual pressing of the hot coating compound applied to the edge area into the pores to be closed in the edge surface. The doctor elements are heated so that the coating composition retains its good spreadability and thus penetrates well into the pores on the one hand and forms a relatively smooth surface on the other.

Advantageously, the doctor elements are set at an acute angle to the edge of the workpiece to be machined in the direction of passage. These angles of attack of the doctor elements in relation to the workpiece edge to be machined are preferably adjustable. Similar to a snow plow, the hot coating compound carried past the doctor elements on the workpiece edge is directed by the doctor elements into the pores of the workpiece edge to be sealed and into pressed this in. In the event that several groups of heated doctor elements are arranged in stages in the direction of passage one behind the other, the setting angles can, for example, be set flatter from stage to stage or otherwise varied. The doctor elements are preferably designed as spatula blades, whose geometric shape is adapted, for example, to a profile of the workpiece edge to be machined.

In one embodiment of the device according to the invention, several application and hot filler stations are arranged one behind the other within the device. In this way the edge coating can e.g. can be subdivided into a preliminary remuneration at a first application and a first hot filler station and into a finished remuneration at a second application and a second hot filler station. Furthermore, by dividing it into several application and hot filler stations connected in series, different remuneration components can be applied in succession to the edge area of the workpiece to be machined. For example, a second, colored, or otherwise modified compensation component can be applied to a first compensation compound.

Preferably, a grinding station is arranged downstream of the device in at least the last hot filler station in the direction of flow. If only one application station and one hot filler station are provided within the device, a fine grinding station, for example, can be connected downstream. In the case of several application and hot filler stations arranged one behind the other, a sanding station can be arranged after each hot filler station if required.

In an advantageous embodiment of the device according to the invention, the processing stations are followed by a painting station within the device, to which a drying station working with ultraviolet emitters or other drying devices and a grinding station are connected. A further embodiment of the invention consists in placing a hot stamping station behind the processing stations within the device, with which, for example, decorative paper foils are stamped onto the workpiece edge. The hot stamping station can either connect directly to the hot filler station or a downstream sanding station or to the coating station with a downstream drying and sanding station. In the latter case, the surface quality of the tempered edge can be further improved by painting before hot stamping. In a further preferred embodiment of the invention, the processing stations within the device are followed by a gluing station for coating with a coating material. This gluing station can also be connected to the hot filler station or a downstream sanding station or to a painting station with a drying and sanding station, depending on whether a tempered or an additionally painted edge surface is a prerequisite for the subsequent coating, e.g. with a thin decorative paper, is required.

Since the hot filling of a hardening compound to seal the material pores in the edge area achieves a very good surface quality of the workpiece edge and thus the sinking of a coating material into surface unevenness or pores is excluded, particularly thin coating materials can be glued or stamped using the hot stamping process.

With the device according to the invention, workpieces made of open-pore materials in the edge area can be processed completely with one and the same clamping, from the profiling to the coating to varnishing, hot stamping, for example of decorative paper foils, or gluing with decorative papers. Due to the compact processing stations and the short required throughput distances, the entire device can be kept short, which results in an inexpensive and space-saving machine. A high system availability is guaranteed by wide processing parameters of the device according to the invention. Due to short changeover times of individual processing stations, even small batch sizes of workpieces can be processed inexpensively and quickly with the device according to the invention. In particular, very thin decorative papers and other very thin coating materials can be applied in good quality to the edge of an open-pore wood-based material or the like, for example a particle board, with the method according to the invention.

The method according to the invention and the device according to the invention are explained in more detail below on the basis of exemplary embodiments with reference to the accompanying drawings:

Fig. 1

eine schematisierte Draufsicht eines Ausführungsbeispieles einer erfindungsgemäßen Auftrags- und Heißspachtelstation;

Fig. 2

eine schematisierte perspektivische Ansicht der Auftrags- und Heißspachtelstation gemäß Fig. 1;

Fig. 3

ein schematisiertes Diagramm der Bearbeitungsschritte eines Ausführungsbeispiels des erfindungsgemäßen Verfahrens;

Fig. 4

eine schematisierte Seitenansicht einer erfindungsgemäßen Vorrichtung zur Durchführung der Verfahrensschritte gemäß Fig. 3.

Show it:

Fig. 1

a schematic plan view of an embodiment of an application and hot filler station according to the invention;

Fig. 2

a schematic perspective view of the application and hot filler station according to FIG. 1;

Fig. 3

a schematic diagram of the processing steps of an embodiment of the method according to the invention;

Fig. 4

3 shows a schematic side view of a device according to the invention for carrying out the method steps according to FIG. 3.

1 shows a flat wooden workpiece 1, for example a particle board, which has an open-pored cutting edge 5 which is to be tempered. The workpiece 1 is clamped in a workpiece clamping device (not shown) and moves with it in the direction of passage (see arrow) of the processing machine.

As shown in FIG. 1, an application roller 2 is arranged on the processing machine, and a heated spatula blade 4 is arranged at a distance behind it in the direction of flow. The spatula blade 4 forms an acute angle α with the workpiece edge 5. The reference number 3 is one Coating compound marked with which the workpiece 1 is tempered in the edge area.

As can be seen in FIG. 2, the workpiece 1 selected in the example has a profiled edge 5, the upper region of which is rounded and the lower region of which is flat. Two spatula blades 4 are provided, of which the upper spatula blade in the drawing is assigned to the upper, rounded region of the workpiece edge 5, while the lower spatula blade in the drawing is assigned to the lower, flat region of the workpiece edge 5. The two spatula blades 4 are arranged slightly offset one after the other in the direction of passage.

The workpiece 1 with the workpiece edge 5 that has already been profiled and ground at a preceding processing station is first passed in the run past the application roller 2. A coating compound 3 is transferred from the surface of the application roller 2 in a hot state, for example at a temperature in the range of approximately 200 ° C., to the workpiece edge 5. The workpiece 1 with the layer of hot coating compound applied to the edge 5 continues to the spatula blade 4, which is heated, for example, to a temperature in the range of approximately 200 ° C. While the hot tempering compound 3 applied to the edge 5 is guided past the spatula blade 4 in the direction of travel, the compound is guided by the latter to the open pores 6 of the workpiece edge 5 and pressed into the pores 6 so that they are closed. In this way, the coating compound 3 penetrates evenly into the pores 6 and the unevenness of the workpiece edge 5, and by means of the spatula blade 4, in addition to the uniform introduction of the coating compound into the open-pore workpiece edge, a smooth outer surface of the coating compound layer is simultaneously obtained achieved after hot filling, as is illustrated schematically on the left edge of the image in FIG. 1.

1 shows method steps A to I in a diagram as they can be carried out in a single pass with a constant workpiece clamping in the method according to the invention. In step A, the workpiece to be machined, e.g. a chipboard, clamped in the processing machine. The direction of travel of the machine is marked with an arrow. In step B, the workpiece edge to be machined is profiled by profile milling. This is followed in step C by profile grinding of the workpiece edge. Step D is followed by the application of a hot coating compound and then the hot filling of the coating compound into the remaining pores and unevenness of the profiled workpiece edge, as was explained in detail above. In step E, a grinding process follows. In a further processing step F, lacquer is applied to the workpiece edge which has been tempered in this way. Then in a step G the paint is e.g. dried by ultraviolet radiation and ground in a step H. In a processing step I, hot stamping e.g. embossed with a decorative paper film. As already explained above, individual processing steps can be varied or omitted compared to the exemplary embodiment shown in FIG. 3.

FIG. 4 schematically illustrates a device on which the corresponding processing stations for carrying out the processing steps shown in FIG. 3 are arranged one behind the other in the direction of workpiece passage, ie from left to right in FIG. 4. All processing stations are integrated in one processing machine and the processing steps can be carried out with the same workpiece clamping in one pass that complete processing of the workpiece in the edge area can take place with the processing machine. In particular, a profile milling station B, a profile grinding station C, an application and a hot filler station D, a profile grinding station E, a painting station F, a drying station G, a grinding station H and a hot stamping station I are provided in the direction of flow. All processing stations can be accommodated on a comparatively short throughput path for the workpiece, so that a compact complete processing machine can be implemented.

Claims (22)

Process for continuous machining of essentially flat or strip-shaped workpieces (1) made of open-pore wood-based materials and the like in the edge area (5), with the following steps: - Machining the workpiece in the edge area by milling (B) and / or grinding (C); - Applying (D) a hot coating compound (3) to the edge area (5) and - Hot filler (D) of the compensation compound. Method according to claim 1,
characterized in that
the coating compound (3) and hot filler (D) are applied several times in succession during the run. The method of claim 1 or 2,
characterized in that
hot filling (D) of the coating compound (3) is followed by a grinding step (E). Method according to one of claims 1 to 3,
characterized in that
in addition, a second compensation component is applied to the compensation compound (3). Method according to one of claims 1 to 4,
characterized in that
the processing step of milling and / or grinding is carried out as profile milling (B) and / or profile grinding (C). Method according to one of claims 1 to 5,
characterized in that
as a further processing step, a lacquer application (F) followed by drying (G) by ultraviolet radiation and subsequent grinding (H) takes place during the run. Method according to one of claims 1 to 6,
characterized in that
as a further processing step, hot stamping (I) takes place during the run. Method according to one of claims 1 to 6,
characterized in that
gluing with a coating material is carried out as a further processing step during the run. Method according to one of claims 1 to 8,
characterized in that
the coating compound (3) is a thermoplastic compound, a thermosetting compound or a thermoplastic compound that cures to form a thermosetting compound. Device for carrying out the method according to claim 1, with a clamping device holding the respective workpiece (1) in the passage and the following processing stations arranged one behind the other for continuous processing: - a milling and / or grinding station (B, C), - An order station (D) for the remuneration mass (3) and - a hot filler station (D). Apparatus according to claim 10,
characterized in that
the milling and / or grinding station is designed as a profile milling and / or profile grinding station (B, C). Device according to claim 10 or 11,
characterized in that
the application station is designed as a nozzle, roller (2), transfer belt application unit or the like. Device according to one of claims 10 to 12,
characterized in that
the hot filler station consists of heated doctor elements (4) which are arranged around the edge profile (5) of the workpiece (1) to be machined. Device according to claim 13,
characterized in that
several groups of doctor elements (4) arranged around the edge profile (5) are connected in series in the hot filler station. Device according to claim 13 or 14, characterized in that the doctor elements are set at an acute angle (α) to the edge (5) of the workpiece (1) to be machined in the direction of passage. Device according to claim 15,
characterized in that
the angle of attack (α) of the doctor elements (4) can be adjusted with respect to the workpiece edge (5) to be machined. Device according to one of claims 13 to 16,
characterized in that
the doctor elements are designed as spatula blades (4). Device according to one of claims 10 to 17,
characterized in that
several application and hot filler stations (D) are arranged one behind the other within the device. Device according to one of claims 10 to 18,
characterized in that
a grinding station (E) is arranged downstream of the device at least the last hot filler station (D) in the direction of flow. Device according to one of claims 10 to 19,
characterized in that
a painting station (F) with subsequent drying station (G) with ultraviolet emitters and subsequent grinding station (H) is arranged downstream of the processing stations. Device according to one of claims 10 to 20,
characterized in that
A hot stamping station (I) is arranged downstream of the processing stations within the device. Device according to one of claims 10 to 20,
characterized in that
a gluing station for coating with a coating material is arranged downstream of the processing stations within the device.

Images