EP1790447B1 - Process and apparatus for machining panel-shaped workpieces - Google Patents

Description

Technical area

The invention relates to a method for processing plate-shaped workpieces, which comprise at least a first layer, which consists essentially of wood, wood-based materials or the like, and a second layer, which is harder than the first layer, and an apparatus for performing the method.

State of the art

Plate-shaped workpieces such as furniture fronts or body parts and in particular floor panels (see, for example EP 1 304 427 A ) are often provided with a cover layer which has a high abrasion resistance and, accordingly, a high hardness. Such cover layers are generally referred to as "overlays" in floor panels and consist for example of a melamine resin layer which is enriched with hard particles, which consist for example of aluminum oxide.

The plate-shaped workpieces must normally be machined on their narrow sides, for example to provide there a tongue and groove profile, which can also be selbsteinrastend ("click profile"). Especially with click profiles comparatively much material must be removed from the plate-shaped workpieces to form the spring. It has been shown that the removal of the hard outer layers leads to extremely high wear on the processing tools, usually by milling cutters are formed. After just a short time, grooves in the area of the hard surface layers are formed on the processing tools. This leads first to the fact that the service life of the processing tools compared to a pure woodworking is extremely shortened, resulting in long machine downtime and high costs for re-sharpening or replacing the tools. In addition, the premature wear of the processing tools also affects the quality of the produced plate-shaped workpieces. This is particularly critical in floor panels, since the machining accuracy in the hard facing area for the future Fugenmaß and thus the appearance and the durability of a Paneel floor is of particular importance.

Further, the DE 199 06 209 A1 a method for separating individual circuit units from a panel using a milling process and a laser cutting process. In addition, the reveals DE 299 24 727 U1 a machine tool for workpiece machining with cutting tools and laser beams. In both devices, the respective processing can only be carried out sequentially.

Furthermore, the post-published EP 1 719 596 A1 a method for producing a panel, wherein the panel has a core made of a fibrous material, preferably an MDF or HDF board. In order to increase the quality and precision as well as the water resistance of the panels produced from the panel, it is proposed to laser cut at least one cut on the panel.

Presentation of the invention

It is therefore an object of the present invention to provide a method and apparatus for processing multi-layered plate-shaped workpieces, in which the tool wear is significantly reduced and a rapid operation is possible.

This object is achieved by a method according to claim 1 and an apparatus according to claim 8. Particularly advantageous embodiments of the invention are specified in the dependent claims.

The present invention is based on the idea to avoid chipping the hard layer (s) of the plate-shaped workpieces as much as possible. For this purpose, the invention provides that at least a portion of the second layer will wear away by means of at least one laser, wherein the at least one laser and the plate-shaped workpieces are moved relative to each other. In this way, the at least one cutting tool is largely or completely of a machining of the hard cover layer freed, so that the tool wear is significantly reduced. This results in a significantly longer service life of the cutting tools and correspondingly low breastfeeding and improved quality of the machined workpieces.

In the context of the present invention, a variety of combinations of successively performed laser processing and machining tool machining are possible. According to one embodiment of the present invention, however, it is provided that the second layer is at least partially removed before the first layer. This greatly reduces the likelihood of damaging the cutting tools by the hard second layer.

With regard to the mentioned in claim 1 layers of the plate-shaped workpieces to be processed, it should be noted that the plate-shaped workpieces can of course also have a larger number of layers, and that, for example, the second layer may also be formed by a plurality of layers, the harder are as at least one other layer of the plate-shaped workpiece. In addition, the layers may in principle extend in any way within the plate-shaped workpieces. However, the method according to the invention has proven to be particularly advantageous when the first and the second layer extend essentially in the plane of the plate-shaped workpieces, as is the case, for example, with furniture parts or floor panels. In this case, the method according to the invention is particularly preferably used when such plate-shaped workpieces are to be profiled in the region of its narrow side, for example, in the region of the first section to be provided with a tongue and groove profile.

According to one development of the present invention, it is provided that the at least one section of the second layer is removed by at least two lasers, which preferably have different removal widths. In this approach, a laser, in particular the one with the smaller Abtragbreite be used to produce a sharp and precise separation cut, while another laser, in particular with the larger Abtragbreite, for a less precise, but flat removal can be used , This results in an economical as well as precise procedure.

Alternatively or additionally, according to a development of the present invention, it is provided that the at least one section of the first layer is removed in two steps, wherein in the first step the first layer is processed such that a further section of the second layer is separated from the plate-shaped workpiece , In this way, a large part of the hard second layer can be separated from the plate-shaped workpiece without the hard second layer having to be machined, which not only protects the tools but also reduces the chip removal or dispenses with it. It should be noted that the removal of the chips of the hard second layer is particularly critical, as results in a distortion of the hard second layer, a chip jet, which also leads to significant damage to the chip removal hood or similar chip removal.

A particularly economical and rapid method is obtained when the above-mentioned method steps are performed simultaneously on two opposite sides of the plate-shaped frogs. This is particularly suitable for workpieces that should be provided on opposite sides, for example with tongue and groove.

A particularly efficient and simply constructed device according to the present invention is defined in claim 8.

It is particularly preferred that at least one laser of the device is provided in the conveying direction upstream of the at least one cutting tool. This can reduce the risk that the at least one cutting tool will be damaged by the hard second layer.

Further preferred embodiments of the device according to the invention will become apparent from the dependent claims, wherein the benefits discussed above accordingly can be achieved.

Brief description of the drawings

• Fig. 1 schematically shows a plan view of a processing apparatus according to the present invention;
• Fig. 2 shows schematically a partial sectional view of two manufactured according to the present invention workpieces;
• Fig. 3 schematically shows a partial sectional view of the in Fig. 1 shown device, wherein the section along the line AA in Fig. 1 is guided;
• Fig. 4a schematically shows a partial sectional view of the in Fig. 1 shown device, wherein the section along the line BB in Fig. 1 is guided;
• Fig. 4b schematically shows a partial sectional view of the in Fig. 1 shown device, wherein the section along the line BB in Fig. 1 guided and the viewing direction is reversed;
• Fig. 5 schematically shows a partial sectional view of the in Fig. 1 shown device, wherein the section along the line CC in Fig. 1 is guided.

Preferred embodiments of the present invention

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Fig. 1 schematically shows a plan view of a processing apparatus 10 according to the present invention. The processing device 10 is used for processing plate-shaped workpieces W, for example, to produce floor panels, as in Fig. 2 are shown schematically in a sectional view. As in Fig. 2 can be seen, the plate-shaped workpieces W each have a first layer 1 and a second layer 2, which extend in the plane of the plate-shaped workpieces W. In this case, the second layer 2 has a greater hardness than the first layer 1, wherein the hardness can be measured, for example, as Brinell hardness. The materials of the first layer 1 and the second layer 2 are not particularly limited in the present invention, however, in many applications, the first layer 1 will be a supporting layer consisting essentially of wood, wood-based materials or the like the second, harder layer 2 will often be an abrasion-resistant cover layer which may be formed, for example, by a melamine resin layer provided with hard particles (such as alumina).

Fig. 1 shows in combination two embodiments of the processing apparatus 10, wherein on the right side of Fig. 1 the processing units according to a first embodiment of the present invention are shown while on the left side of FIG Fig. 1 the processing units are shown according to a second embodiment of the present invention. These embodiments may well be as in Fig. 1 shown combined with each other become. It is also possible to use the in Fig. 1 shown processing units each symmetrical on both sides in Fig. 1 or machining units only on one side in Fig. 1 to arrange.

The processing device 10 initially comprises a conveying device 20, for example in the form of a chain or belt conveyor, for conveying plate-shaped workpieces W to be processed in a conveying direction indicated by an arrow. Referring to the right side of Fig. 1 According to the first embodiment of the present invention along the conveyor 20 first a first laser 12, then a second laser 14 and finally a cutting tool 18, for example in the form of a profile cutter arranged. The lasers 12, 14 are preferably CO ₂ lasers, although other types of lasers such as diode lasers, Nd: YAG lasers, excimer lasers or the like may also be used. The power of the laser is not particularly limited in the present invention, but should be set such that at a predetermined conveying speed of the plate-shaped workpieces, the second layer 2 is completely severed. Furthermore, the lasers 12 and 14 may be identical lasers, but it is preferred that the second laser 14 have a greater ablation width than the first laser 12, as will be explained in more detail below.

Referring to the left side of Fig. 1 For example, a second embodiment of the device according to the invention also comprises first a laser 12, as described above, followed by a first cutting tool 16 and a second cutting tool 18. The first cutting tool 16 is a saw blade in the present embodiment whose axis of rotation extends substantially perpendicular to the plane of the plate-shaped workpieces W. In which Machining tool 18 is here again a profile cutter.

The operation of the first embodiment of the device according to the invention or a first embodiment of the method according to the invention will be described below with reference to FIGS FIGS. 3, 4a and 5 described. First, as in Fig. 3 1, a plate-shaped workpiece W conveyed along the conveyor 20 is processed by the first laser 12 such that a first section 2 'of the second layer 2 is removed. In this case, this section 2 'extends completely through the second layer 2 and may optionally also extend into the first layer 1. Subsequently, the plate-shaped workpiece W is conveyed on to the second laser 14, which completely removes a further section 2 "of the second layer 2 ( Fig. 4a ). It is how a comparison of FIGS. 3 and 4a Then, the plate-shaped workpiece W reaches the machining tool or the profile cutter 18, where the profile of the cutter 18 facing narrow side of the plate-shaped workpiece W is provided with a desired profiling, for example with a groove or a spring. Subsequently, the plate-shaped workpiece W is discharged. It should be noted that the plate-shaped workpiece is conveyed by the conveyor 20 continuously (in the pass).

The operation of the second embodiment of the device 10 according to the invention or a second embodiment of the method according to the invention will be described below with reference to FIGS FIGS. 3, 4b and 5 described. First, as in Fig. 3 shown and already described with reference to the first embodiment, a conveyed by the conveyor, plate-shaped workpiece W processed by the first laser 12 such that in the area the second layer 2, a first portion 2 'is removed. Subsequently, as in Fig. 4b shown by the saw 16, a portion 1 'of the first layer removed such that the adjacent portion 2''of the second layer 2 is completely detached from the plate-shaped workpiece W. In this way, a majority of the hard layer 2 can be separated from the plate-shaped workpiece W without being chipped. Subsequently, as already described in the first embodiment, the end face of the plate-shaped workpiece W is provided by the profile cutter 18 with a desired profile.

In addition to the above-described embodiments, it is to be noted that the present invention, in its most general aspect, aims to laser-ablate the first layer 1 of the plate-shaped workpieces W by a cutting tool and the second layer 2 of the plate-shaped workpieces W. Against this background, the present invention also includes devices having only a laser 12 and a machining tool 18 in combination with a conveyor 20. In this case, the inventive method comprises only in FIGS. 3 and 5 shown process steps.

Finally, it should be noted that the method or device according to the present invention can be supplemented and combined with a multiplicity of additional method steps or device components. For example, it is possible to provide pre-milling units or the like upstream of the first laser 12 in order to remove a portion of the first layer 1 at a suitable location and thus to relieve the profile milling cutter.

Claims (13)

1. Method for working board-like work pieces (W), with the steps of:

   providing board-like work pieces (W) which have at least one first layer (1) which is essentially made of wood, wood materials or the like, and a second layer (2) which is harder than the first layer,

   removing at least a section (2', 2") of the second layer (2) using at least one laser (12, 14), the at least one laser (12, 14) and the board-like work pieces (W) being moved relative to each other continuously, and

   removing at least one section (1', 1'') of the first layer (1) using at least one cutting tool (16, 18), the removed section (1', 1") of the first layer (1) being located adjacent to the removed section (2', 2") of the second layer (2) .
2. Method according to claim 1, characterised in that the second layer (2) is at least partially removed before the first layer (1).
3. Method according to claim 1 or 2, characterised in that the layers (1, 2) extend substantially in the board plane of the board-like work pieces (W) and preferably the at least one section (1', 1") of the first layer (1) in the region of at least one narrow side (W') is removed.
4. Method according to any of the preceding claims, characterised in that the at least one section (2', 2") of the second layer (2) is removed by at least two lasers (12, 14) which preferably have different removal widths.
5. Method according to any of the preceding claims, characterised in that the at least one section (1', 1") of the first layer (1) is removed in two steps, the first layer (1) being worked in the first step in such a way that a further section (2") of the second layer (2) is separated from the board-like work piece (W).
6. Method according to any of the preceding claims, characterised in that a groove-like or tongue-like profile is produced on the first layer (1) by removing the at least one section (1', 1") of the first layer (1), in particular a so-called click profile.
7. Method according to any of the preceding claims, characterised in that the steps of the method are performed substantially simultaneously on two opposite sides of the board-like work pieces (W).
8. Working apparatus (10) for carrying out the method according to any of the preceding claims, comprising:

   at least one cutting tool (16, 18) which is suitable for working wood, wood materials or the like,

   at least one laser (12, 14), and

   a continuous conveying device (20) for producing a relative movement continuously between the at least one cutting tool (16, 18) or the at least one laser (12, 14) on the one hand and board-like work pieces (W) to be worked on the other hand.
9. Working apparatus according to claim 8, characterised in that at least one laser (12, 14) is provided upstream of the at least one cutting tool (16) in the direction of conveying.
10. Working apparatus according to claim 8 or 9, characterised in that it has at least two lasers (12, 14) which preferably have different removal widths.
11. Working apparatus according to any of claims 8 to 10, characterised in that at least two cutting tools (16, 18) are provided.
12. Working apparatus according to claim 11, characterised in that a first cutting tool (16) is formed by a saw, and/or in that a second cutting tool (18) is formed by a profile milling cutter.
13. Working apparatus according to any of claims 8 to 12, characterised in that on two opposite sides of the conveying device (20) are provided in each case at least one laser (12, 14) and at least one cutting tool (16, 18).

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