DE102014214686A1 - Tempering a workpiece surface - Google Patents

Abstract

The present invention relates to a method for tempering a surface of a workpiece, as well as a corresponding device. Such a method and device are used in the field of component and furniture industry. The method comprises the steps of providing a material obtained during processing of a semifinished product, preferably wood material, in particular wood chips or dust, mixing the resulting material with a binder to form a curable mixture, and applying the curable mixture to the surface to be coated workpiece

Description

Technical area

The present invention relates to a method for tempering a surface of a workpiece, as well as a corresponding device. Such a method and device are used in the field of component and furniture industry.

State of the art

In the field of component and furniture industry chipboard is increasingly being used to achieve further cost reduction in production. Chipboard are usually produced in presses. For the further processing of chipboard, which are delivered as semi-finished products in defined sizes, these are divided to a certain extent. Before the actual surface finishing, in particular the application of a coating / edge material in narrow surface areas, they are then again dimensionally processed.

The proportion of MDF boards also used in this area is decreasing. However, chipboards have the disadvantage over MDF boards that the narrow sides of the workpieces, in the area of which the core layer of the chipboard is exposed, are relatively porous and possibly also have comparatively large pores. In order to be able to further process chipboard with a view to quality requirements, for example, to attach an edge material to a narrow surface of such a chipboard, it is therefore necessary to "smooth" the narrow surface of the workpiece, i.a. to close the open pores of the core layer of the chipboard.

For this purpose, it is known to apply a hotmelt adhesive in the region of the narrow side of the chipboard, which at least partially penetrates into the pores and closes them. However, the use of the hot melt adhesive has the disadvantage that the resulting surface is relatively compliant and machining for creating a defined geometry with cutting tools leads to difficulties. After application of a coating material, the hotmelt adhesive may have the disadvantage that, unless the hotmelt adhesive is removed, it forms an elastic body between the core layer and the coating material.

An alternative method is therefore the use of UV varnish. In this case, the thus annealed surface can be machined after curing of the UV varnish. However, the UV varnish is relatively expensive, so that its use is rather uneconomical, especially when chipboard are used as a comparatively inexpensive material.

Another way to close the pores of the core layer of a chipboard or the like is the use of a UV hot melt adhesive, which can also be machined as the UV coating after application and curing. But even the raw material of the UV hot melt adhesive is very expensive and causes the UV hot melt adhesive reached no economic breakthrough.

As a document is the WO 2001/047683 A1 which discloses a surface treatment agent comprising a film-forming plastic composition and filler elements. In one embodiment, a surface treatment agent in liquid form is provided which contains wood flour in addition to a film-forming plastic composition as a filler. The wood flour is provided in a range of 40-80% by volume. To cure the film-forming plastic composition, UV curing, heat curing or acid curing is preferred. In some examples, the plastic composition to be formed is a non-liquid but highly viscous liquid.

Subject of the invention

The present invention aims to provide a method and a device, with which a piece-wise pores having workpiece, such as a chipboard, before the further processing, in particular the application of a coating material, can be tempered. The method and the device should be inexpensive to implement and enable improved environmental performance.

The subject-matter of claim 1 provides a corresponding method. Further preferred embodiments are listed in the dependent claims. Furthermore, the present invention aims with a device according to claim 10 to a solution.

The field of application of the present invention is in particular in the range of workpieces which have sections of workpiece surfaces having pores, as is the case with chipboard in the region of the core layer exposed on the narrow sides.

Even if, in the example of chipboard, the so-called broad sides are already provided with a cover layer during production, the invention is not limited to use in such workpieces. Others too Sections as the narrow sides may possibly have pores and should nevertheless be provided with a coating material in high quality, so that the inventive coating can also be used in these areas.

In the context of the present invention, a material "produced during processing of a semifinished product" is mixed with a binder to form a curable composition. The use of a material produced during the processing of a semifinished product realizes effective recycling, in particular if the "accumulating material" is "produced" in the area where its further use takes place (mixing with binder and tempering of a workpiece surface). In the latter case, therefore, not only a recycling takes place, but it can also short ways are guaranteed, especially if the processing of the semifinished product and the compensation of a workpiece surface in the immediate vicinity, possibly in the same or an adjacent production line or the same machine , respectively.

A semifinished product in the furniture and component sector is preferably a chipboard, an HDF board, an MDF board, a composite board, a lightweight building board with honeycomb structure, a plywood element or a laminate workpiece. For example, it may be a door element with a composite structure.

The "accumulating material" includes wood chips or grains, as they occur during a milling or grinding process of a chipboard. In this concrete example, depending on the material consistency of the starting workpiece, from which the resulting material is removed, the material proportions vary: A chipboard contains not only wood-based components but also other additives, which can also be included in the "accumulating material".

In order to advance the environmental idea further, the abovementioned material "accumulating during processing of a semifinished product" can be used in the further processing of such semi-finished products.

In a preferred embodiment, the material produced during processing of a semifinished product, preferably wood chips or dust, is prepared before mixing with the binder, in particular ground, comminuted and / or sieved to adapt the chip or grain size. In this way, the resulting material can be prepared for use as a filler, so that the surface to be coated reaches excellent surface properties.

Furthermore, it is preferred that the surface is post-processed after curing of the mixture, in particular machined by machining. This can be done with a milling cutter or a grinder. In this way, the surface of the surface provided with the curable mixture is further improved.

In a further variant, the method is characterized in that a machinable lacquer is applied to the surface, wherein the application preferably takes place after curing of the mixture. Thus, this variant provides a further compensation step.

Further, the curable composition applied to the surface may be shaped with a former prior to curing. In this way, the curable mixture is possibly further pressed into pores of the surface of the workpiece, or it is achieved an additional smoothing.

Also, the workpiece with the surface to be coated can be a chipboard. Thus, the recycling of materials allows (accumulating material), which may otherwise be disposed of, especially in the same or similar types of work that already used to recover the resulting material.

In a further embodiment, the binder is an adhesive, in particular a wood glue. For example, the adhesive is PVAc (polyvinyl acetate), a two-part adhesive, or a bio-polymer based adhesive. Also can be used as a binder extrudable wood material, for example using PP or PE.

In a further embodiment, the mixture is cured by means of electromagnetic radiation, in particular by means of microwave, laser radiation, IR radiation, plasma or hot air. In this way, a rapid further processing of the surface provided with the curable mixture is possible.

Furthermore, the present invention relates to a device for the compensation of a surface of a workpiece, in particular for carrying out the method according to one of the aforementioned aspects, which device comprises the features of claim 10.

In one embodiment, the device is equipped with a processing device for processing the material arising during the processing of a semifinished product, in particular for adapting the chip or grain size of the resulting material Material by grinding, crushing and / or sieving.

In one embodiment, the apparatus is further provided with a post-processing device for post-processing, in particular post-machining, the surface in order to further compensate for the surface provided with the curable mixture.

Furthermore, the device may be provided with a shaping device for shaping the applied mixture. In this way, if necessary, the curable mixture is pressed even further into pores of the surface of the workpiece or an additional smoothing of the created surface is achieved. In one embodiment, the shaping device is a sliding shoe.

A device for applying a machinable paint to the surface is a further optional component within the scope of the invention, wherein the device may be provided separately from the application device.

Brief description of the drawings

1 shows a schematic process flow according to an embodiment of the present invention.

The present invention will be described below with reference to a preferred embodiment. Other modifications of certain individual features mentioned in this connection can each be combined with one another in order to define new embodiments. Furthermore, the described embodiment as well as the modifications are not restrictive and may be suitably modified within the scope of the claims set out in the claims.

Chipboard is usually produced in relatively large formats of, for example, 5 × 2.5 m in presses. Such particleboard represent semi-finished products, which are divided for further processing. Before the actual surface finishing, for example, the application of a coating material, the plate blanks are again processed dimensionally stable. This dimensional editing is also referred to as formatting (see step S1 in FIG 1 ).

The material produced in the machining of the chipboard, in particular chips and other materials contained in chipboard (hereinafter also referred to as "accumulating material") are processed in the present embodiment (step S2), in particular brought to a defined maximum grain size / crushed, for example, ground, separated or chopped, and / or sieved. By sieving the material produced during the machining of the chipboard, grains or shavings which are already suitable for further processing can be quickly filtered out, while grains or shavings which are too large are subjected to further processing, for example to a comminuting device.

In addition, ingredients can be filtered out in the process step of the preparation, since in the case of chipboard and in the use of the costs incurred in dividing the chipboard material higher wood proportions may be desired. In one example, the material is ground and fed to a water bath so that the wood grains float on the water surface while heavier materials sink in the water.

Furthermore, in certain variants of the present embodiment, the processing may include the admixing of additives, for example in order to make the accumulated (wood) material more flexible.

The obtained in the manner described above and possibly processed, accumulating material can be mixed in a further embodiment with other wood material, such as wood flour or other wood chips.

Alternatively or additionally, it is also possible to use a material which is produced externally instead of the treatment of material arising during the machining of the chipboard. For example, sawdust or sanding dust can be used. Thus, the step S2 can be skipped. However, this material can also be subjected to one of the aforementioned treatment steps.

In each of the aforementioned alternatives, a wood-based material, possibly with further portions, is thus provided, which can thus be provided or kept in a memory.

This material is mixed with an adhesive or adhesives, in particular PVAC, (step S2) in such a way that the wood-based material occupies 50% by volume, in particular 70% by volume, particularly preferably 80% by volume or more as base material , The material mixed with the adhesive is hereinafter also referred to as a "curable mixture".

Subsequently, the curable mixture is pressed by means of pumps, for example by means of screw pumps, through a nozzle and applied to the narrow surface of a chipboard (step S4). Possibly. is the thus pressed-on mixture, which at least partially penetrates into the pores of the chipboard, brought into shape by means of a shoe or a doctor blade.

Subsequently, the curable mixture is dried or cured (step S5). For example, if PVAC glue is used as an adhesive for the curable mixture, it can be cured relatively quickly by means of a microwave energy source. Air drying is also possible after activation of the hardenable mixture.

After curing, the treated with the curable mixture surface of the chipboard, in particular the narrow side, again machined and brought into a defined dimensionally stable shape (step S6).

Possibly. It is possible that the rapid curing of the curable mixture pores in their structure. In this case, a further layer can be applied after the application of the curable mixture and the optionally machining. Thus, conventional finishing materials can be used, such as UV varnish, UV-melt adhesive or hot melt adhesive. However, with the process step already carried out (application of the hardenable mixture), a closure of the large pores could be achieved with a comparatively inexpensive filling material, and a significantly smaller amount should be used for the final surface finishing with a more costly material.

In a further method step, a coating material is then applied to the coated surface (step S7).

The present invention thus has the advantage that a comparatively inexpensive filler (curable mixture) is provided for the particleboard which is increasingly being used, in some cases with relatively large pores. This leads to possible cost savings in improving the surface quality of a narrow surface of the particularly porous plates. In addition, the ecological use should also be pointed out, since on the one hand wood material is used as a filler and, in the above-described direction, is set especially on recycled material.

The present invention is not limited to use in the field of chipboard, but can be used in workpieces that due to their production or processing - have comparatively large pores, defects or the like on a surface with a finishing layer, such as a coating material how to provide an edge band.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2001/047683 A1 [0007]

Claims (14)

A method for tempering a surface of a workpiece, wherein the workpiece is preferably at least partially made of wood, wood materials, plastic or the like, comprising the steps of: Providing a material arising during processing of a semifinished product, preferably wood material, in particular wood chips or dust, Mixing the resulting material with a binder to form a curable mixture, Applying the hardenable mixture to the surface of the workpiece to be coated, and preferably at least partially curing the mixture. A method according to claim 1, characterized in that the accumulating during a processing of a semifinished material prepared prior to mixing with the binder, ground in particular to adapt the particle or grain size, crushed and / or sieved. Method according to one of the preceding claims, characterized in that the surface post-processing after curing of the curable mixture, in particular post-processed by machining, for example. Milled or and / or ground, is. Method according to one of the preceding claims, characterized in that the semifinished product is a chipboard, an HDF board, an MDF board, a composite panel, a lightweight board with honeycomb structure, a plywood element or a laminate workpiece. Method according to one of the preceding claims, characterized in that on the surface of a machinable lacquer, in particular UV lacquer, or UV hot melt adhesive is applied, or a laminating material, preferably made of paper or a thin edge, or plastic film is applied, wherein the application preferably takes place after curing of the curable mixture. Method according to one of the preceding claims, characterized in that the curable mixture applied to the surface is brought into shape with a shaping device before hardening. Method according to one of the preceding claims, characterized in that the workpiece with the surface to be coated is a chipboard. Method according to one of the preceding claims, characterized in that the binder is an adhesive, preferably PVAc, in particular a wood glue, a two-component adhesive, a biopolymer with an additive or extrudable wood material. Method according to one of the preceding claims, characterized in that the mixture is cured by means of electromagnetic radiation, in particular by means of microwave, laser radiation, IR radiation, plasma or hot air. Apparatus for the compensation of a surface of a workpiece, in particular for carrying out the method according to any one of the preceding claims, wherein the workpiece is preferably at least partially made of wood, wood materials, plastic or the like, with a storage device for receiving a material arising during processing of a semifinished product, preferably wood material, in particular wood chips or dust, a mixing device for mixing the resulting material with a binder to form a curable mixture, a application device for applying the hardenable mixture to a surface to be coated of the workpiece, and preferably a curing device for at least partial curing of the applied mixture. Apparatus according to claim 10, further comprising a processing device for processing the resulting in the processing of the semifinished material, in particular for adjusting the chip or grain size of the resulting material by grinding, crushing and / or sieving. Device according to one of claims 10 to 11, further comprising a post-processing device for reworking, in particular post-machining, for example. Milling or grinding, provided with the curable mixture surface. Apparatus according to any one of claims 10 to 12, further comprising shaping means for shaping the applied mixture. Device according to one of claims 10 to 13, further comprising a device for applying a machinable paint on the surface, in particular UV coating, or UV hot melt adhesive, or a laminating material, preferably made of paper or a thin edge.

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