Device for cleaning a coating material, system for finishing a coating material, and method for cleaning a coating material

Abstract

The invention relates to a device (1) for cleaning a coating material, in particular a coating material provided on a workpiece (20), the workpiece preferably consisting at least partially of wood, wood materials or plastic, said device comprising a cleaning element (3) for removing dirt from the coating material, a supply means for supplying a cleaning liquid, and at least one first and one second pressing means (4, 4') for pressing the cleaning element (3) against the coating material, the device being designed such that the supply means supplies the cleaning liquid to the first pressing means (4) in such a manner that said cleaning liquid is discharged onto the cleaning element (3) via the first pressing means (4) in order to thus be applied to the coating material, while less cleaning liquid, preferably substantially no cleaning liquid, is supplied to the second pressing means (4') by the supply means.

Description

[0001] Device for cleaning a coating material, system for refining a coating material and method for cleaning a coating material

[0002] Technical area

[0003] The present invention relates to a device for cleaning a coating material and a method therefor. It also relates to a system for refining a coating material.

[0004] State of the art

[0005] In the furniture and construction component manufacturing sector, workpieces made of wood or wood-based materials, for example, are often coated on their surface with a coating material, typically made of plastic. This coating material can have patterns or, during finishing, receive additional patterns to make it appear more similar to a wood-based material.

[0006] In order to apply such patterns, it is known from the prior art, such as WO 2022 / 171661 A1, that the strip-shaped coating material, which is applied to a workpiece, is printed using a printing process in order to apply a desired pattern. This leads to a coated workpiece with a higher optical quality. To apply the pattern, however, it is necessary to remove contaminants adhering to the coating material, such as fingerprints. In this way, according to WO 2022 / 171661 A1, a strip-shaped

[0007] Cleaning material is passed over the coating material. This cleaning material absorbs the contaminants, allowing the coating material to be cleaned more effectively and thus printed more effectively.

[0008] However, the inventors have noticed that these devices are in need of improvement in terms of process speed, process stability, and the need for consumables. The present invention aims to achieve at least some of these goals or to improve the aforementioned devices with regard to the aforementioned parameters.

[0009] Description of the invention

[0010] The invention is defined by independent claims 1, 18 and 19. Preferred embodiments are defined in the dependent claims.

[0011] According to claim 1, a device for cleaning a coating material is defined. Such a coating material can be, for example, a plastic edge band, which is typically applied and, in particular, glued to the narrow side of a workpiece to be coated. The workpiece preferably consists, at least in sections, of wood, wood-based materials, or plastic and can, in particular, consist of a pressboard material.

[0012] According to the invention, the device has a cleaning element for removing contaminants from the coating material. This is an element by means of which the contaminants can be removed and thus no longer stand in the way of subsequent finishing of the coating material. Removal means at least partial removal of the contaminants. There is also a supply means for supplying a cleaning liquid. A cleaning liquid can be supplied through this means, which, as will be described in detail later, serves to clean the coating material.

[0013] There are also at least a first and a second pressing means for pressing the cleaning element against the coating material. This pressing ensures a good contact and adaptation of the cleaning element to the coating material, so that the coating material can be effectively cleaned by the cleaning element.

[0014] According to the invention, the device is designed such that the supply means supplies the cleaning liquid to the first pressing means, so that the cleaning liquid is dispensed onto the cleaning element via the first pressing means. In this way, the cleaning liquid can be applied to the coating material and can thus clean it. However, the supply means supplies no cleaning liquid, or at least less cleaning liquid, to the second pressing means. This results in cleaning with a reduced amount of cleaning liquid and, in particular, dry cleaning. By means of a corresponding design, the consumption of cleaning liquid is reduced, while the advantages of wet cleaning and dry cleaning are combined.

[0015] Preferably, at least one, and preferably all, of the pressure means on the surface that bears against the cleaning element comprises a material that can absorb, store, and / or release a liquid. Such a material can store the cleaning liquid and thus serves as a buffer that can compensate for or buffer fluctuations in the amount of cleaning liquid supplied or fluctuations in the amount absorbed by the cleaning element.

[0016] The material preferably comprises fleece and / or felt and / or is made of a multi-component material of natural or synthetic origin. Such materials are particularly inexpensive and well-suited for use in industrial environments.

[0017] Preferably, the material is replaceable, preferably without tools. This allows it to be easily replaced when it becomes worn, resulting in consistently high cleaning quality.

[0018] Preferably, at least one, and preferably all, of the pressure means comprises a roller coated with the material. Such a roller can roll along the coating material, which reduces friction and thus wear on the material. This leads to a consistently high cleaning quality. In this case, wetting occurs on the coated roller, which transfers the cleaning fluid to the cleaning element during movement, thus cleaning the workpiece.

[0019] Preferably, the device is designed such that the force with which at least one, preferably all, pressing means are pressed against the coating material oscillates. This can lead to better cleaning and / or a reduction in the need for cleaning fluid.

[0020] It is further preferred that a collecting means for excess cleaning liquid is provided. This collecting means can collect any cleaning liquid that is superfluous, thus preventing it from spreading uncontrollably. It is further preferred that a means is provided for feeding the cleaning liquid collected by such a collecting means to the feed means. This makes it possible to return the cleaning liquid to the feed means and thus achieves greater efficiency. However, it is assumed that in almost all relevant applications a filter device is provided to clean the returned cleaning liquid before it is applied to the coating material. This filter device is particularly necessary if the material wears out with fiber formation, as is the case with felt and / or nonwoven materials.

[0021] Furthermore, it is preferred that a device be provided for supplying gas, preferably purified compressed air, to the material. This serves to blow out any liquid contained in the material and can thus be used to dry the material. This also allows the material to be freed from any contaminant particles that may have dissolved in the cleaning liquid.

[0022] Furthermore, it is preferred that a device for drying the coating material be provided. This reduces the time that must elapse before the coating material can be finished. At the same time, it is possible to significantly increase the process speed. Such a drying unit can be implemented, for example, by applying hot air or by using a radiation source, for example, an infrared radiator.

[0023] Furthermore, a device for measuring the amount of liquid absorbed in the material is preferably present. Such a device can, for example, measure the electrical conductivity of the material. This allows monitoring of the material's moisture content, which improves the controllability of the device. At the same time, this also allows a reduction in the required amount of cleaning liquid.

[0024] Furthermore, the gas supply device and / or the device for drying the coating material are controlled at least partially based on the output of the device for measuring the amount of liquid. This ensures that, for example, if a large amount of liquid is present in the material, the amount of gas supplied for drying it is increased. The drying of the coating material can then also be intensified, since it can be assumed that an increased amount of cleaning liquid has also been applied to it.

[0025] Preferably, at least four pressure means are provided. This allows for particularly good adaptation of the pressure to the contour of the coating material.

[0026] Preferably, at least two of the pressing means are movable independently of one another in a direction perpendicular to a direction of travel of the coating material. The direction of travel of the pressing means is perpendicular to the direction of travel of the coating material and also perpendicular to the pressing direction of the pressing means. Due to such mobility, the pressing means can better adapt to the contour of the coating material.

[0027] Preferably, the pressing means each have their own pressing device, by means of which they can be individually pressed against the coating material. This allows the pressing force of the pressing means to be individually controlled, which leads to better cleaning. Furthermore, it is also possible to control the pressing force of the pressing device via a sensing device or a pressure sensor integrated into the pressing means, so that the pressing force is always constant. This further improves process reliability.

[0028] Furthermore, a shaping device is preferably provided to deform the pressing means so that it adapts to the surface geometry of the workpiece. This leads to better pressing of the cleaning element and thus to better cleaning.

[0029] Preferably, the cleaning element is provided as a belt that is movable relative to the coating material. Both the coating material and the cleaning element can be displaced or moved. Only the relative movement between these two components is important.

[0030] Furthermore, a device is preferably provided for determining the amount of unused tape of the cleaning element. This can alert a user of such a device that the tape should be replaced if it is used up prematurely.

[0031] Furthermore, the invention relates to a system for finishing a coating material, which system has a cleaning device as previously described. In such a system, a device for patterning, in particular printing, the cleaned coating material is provided. The device for cleaning the coating material is arranged upstream of the device for patterning the cleaned coating material. Since the coating material patterned by this device has been previously cleaned, the quality of the thus finished coating material is increased.

[0032] Furthermore, the invention relates to a method for cleaning a coating material. This coating material is preferably provided on a workpiece which ideally consists at least in sections of wood, wood-based materials or plastic. In this case, a device is used as previously mentioned, which serves to clean the coating material. In this case, a relative movement between the cleaning element and the coating material is achieved by means of a conveyor unit. A preferably liquid cleaning agent is then applied to the cleaning element. The contaminants are then removed from the coating material by means of the cleaning element. Such a method is particularly advantageous for the reasons stated in relation to the device claims.

[0033] Preferably, the coating material consists at least partially, preferably entirely, of plastic. Such a coating material is particularly suitable for coating workpieces used in furniture manufacturing.

[0034] Short description of the drawings

[0035] Figure 1 shows a device for cleaning a coating material according to a first embodiment of the invention.

[0036] Figure 2 shows a detailed view of Figure 1 .

[0037] Figure 3 shows a device for cleaning a coating material according to a second embodiment of the invention.

[0038] Detailed description of the drawings

[0039] Figure 1 shows a first embodiment of the invention. In a device 1, a workpiece 20, which is provided with a coating material (not shown), is moved along the conveying direction indicated by an arrow. The coated surface lies opposite a belt-shaped cleaning element 3, which is mounted on rollers 2 and can be moved over these. The cleaning element 3 is moved relative to the workpiece 20 by the rolling up and down movement of the rollers 2 and thus removes dirt. In the present case, the cleaning element 3 is conveyed from right to left (counter-rotation!), so that the right side is the upstream side, while the left side is the downstream side.

[0040] In Figure 1, two pressure elements 4, 4' are also provided. These are arranged one after the other along the direction of travel and serve to

[0041] Press the cleaning element 3 against the workpiece 20.

[0042] In the upstream first pressure element 4, a device for supplying cleaning fluid is provided, via which the cleaning fluid can be applied to the cleaning element 3. The cleaning element 3 is made as a fabric belt that can absorb a fluid and dispense it onto the coated surface of the workpiece 20. The relative movement between the workpiece 20 and the cleaning element 3 removes contaminants present on the coating of the workpiece 20.

[0043] For supplying cleaning fluid, channels 6 are provided in the first pressure element 4, which open into a bore in the contact area between the first pressure element 4 and the cleaning element 3. The downstream second pressure element 4' does not have such a supply. Although corresponding channels 6 are also provided here, they are not coupled to a corresponding supply device, so that no cleaning fluid is supplied via the second, downstream pressure element 4'. The possibility of coupling to a supply unit nevertheless exists.

[0044] The contact surface of the first and second pressing elements 4, 4' against the cleaning element 3 is formed by an arcuately shaped felt material 5. This felt material 5 has a certain internal resistance and thus leads to a deformable pressure against the cleaning element 3. The felt material 5 is an example of a material that can absorb a liquid (such as a cleaning liquid), as defined in the claims.

[0045] In the second pressing element 4', a measuring device 10 is further provided to measure the amount of liquid contained in the felt material 5, for example by using a capacitive sensor.

[0046] Further downstream is a device 9 for drying the workpiece, which, as already mentioned, may comprise a hot air supply or an infrared lamp. The device 9 for drying the workpiece 20 is provided here as a separate device from the second pressing element 4'.

[0047] The pressing elements 4, 4' are shown in detail in Figure 2. Using an actuator 11 as an example of a pressing device, they can be displaced relative to the workpiece 20 so that they are closer to or further away from the workpiece 20.

[0048] Below the felt material 5 is a collecting tray 7 for collecting excess cleaning fluid emanating from the felt material 5. This fluid can be drained into a separate container or it can be fed back into the channels 6. However, in almost all cases, filtering of the cleaning fluid is necessary, since felt materials and other types of textiles, in particular, secrete fibers.

[0049] Furthermore, a gas supply device 8 is provided, through which gas, in particular purified compressed air, can be supplied to the material 5 in order to blow out liquid located in the material 5. A corresponding design can be provided in each of the pressing elements 4, 4'. The gas supply device 8 has a channel which opens into the felt material 5. It is conceivable to provide this gas supply device 8 not only in the first pressing element 4, via which cleaning liquid is supplied, but also in the second pressing element 4', which serves for dry cleaning, in order to supply the second pressing element 4' from the liquid located there.

[0050] Cleaning fluid which is transferred via the cleaning element 3.

[0051] Particularly preferably, the workpiece can be moved in one direction, while the cleaning element 3 in the form of a belt is moved in a second direction opposite to this first direction. The movement of the belt can be continuous or intermittent. In a timed cleaning process, the belt stands still during cleaning and is only rotated or conveyed further after the workpiece has been cleaned. During this conveyance of the cleaning element 3, the pressing elements 4, 4' are preferably retracted so that they come out of contact with the cleaning element 3 in order to reduce the tension in the cleaning element 3 and also to avoid friction between the felt material 5 and the cleaning element 3 and the associated wear.

[0052] According to a preferred embodiment, the pressure force of the pressure elements 4, 4' oscillates against the cleaning element 3. In this case, the entire pressure element 4 can be set into oscillation. However, it would also be sufficient if only the felt material 5 were set into such oscillation.

[0053] The embodiment shown in Figure 1 also includes a monitoring sensor device in the form of a sensor, for example, a laser sensor (not shown), which monitors whether sufficient cleaning element 3 in the form of a belt is still available. This can inform a user that it needs to be replaced.

[0054] By using, for example, felt material 5, which has a storage and buffering effect for the cleaning fluid, the process is simplified and economical use of cleaning fluid can be achieved. However, it is also conceivable for the felt to have different thicknesses and / or densities in the z-direction, which is the upward and downward direction, which in turn influences the buffering effect for the fluid.

[0055] Figure 3 shows a second embodiment of the invention. In this embodiment, the device 1 has first to fourth pressing elements 4, 4', 4'', 4''', which are arranged upstream of a device 9 for drying the coating material. These pressing elements 4-4''' can be controlled individually and, in particular, can be pressed individually against the cleaning element 3. This second embodiment is particularly advantageous for cleaning profiled components. The individual pressing elements 4-4''' can be used for different, specific areas of the workpiece surface. For example, two of the pressing elements 4-4''' can be used for wet cleaning, while the other two pressing elements 4-4''' are used for dry cleaning.It is envisaged that, for example, the first and second pressure elements 4, 4' in the direction of travel serve for wet cleaning, while the third and fourth pressure elements 4'', 4'' ' serve for dry cleaning. Alternatively, the first and third pressure elements 4, 4'' can be used for wet cleaning, while the second and fourth pressure elements 4', 4'' ' are used for dry cleaning. In this case, the pressure elements used for wet cleaning are each subjected to the same cleaning fluid.

[0056] In such an embodiment, it is conceivable that the pressing elements 4-4 ' ' ' are geometrically designed such that they are in contact with a corresponding complementary contour of the workpiece 20. For example, the first and second pressing elements 4, 4' can be in contact with both a surface of the workpiece 20 and the side surface of the workpiece 20, while the third and fourth pressing elements 4 ' ', 4 ' ' are in contact with the underside and the side surface of the workpiece 20. It is also possible for the pressing elements 4-4 ' ' ' to be movable relative to one another in the z-direction such that workpieces 20 with different thicknesses can be cleaned.

[0057] Alternatively, it is also possible for only two pressing elements 4-4 ' ' ' to be provided, wherein these pressing elements 4-4 ' ' ' have at least one shaping device in the z-direction, which makes it possible to deform the pressing elements 4-4 ' ' '4 themselves in such a way that they adapt to the surface geometry or contour of the workpiece 20. This enables the cleaning of workpieces 20 with different geometric characteristics.

[0058] By means of the invention as described in the first and second embodiments, the consumption of cleaning fluid and cleaning agent in the form of tape can be reduced, since these can also be dosed in a more precisely controlled manner.

Claims

CLAIMS 1. Device (1) for cleaning a Coating material, in particular a coating material provided on a workpiece (20), wherein the workpiece (20) preferably consists at least in sections of wood, wood materials or plastic, with: a cleaning element (3) for removing dirt from the coating material, - a supply means for supplying a cleaning liquid, and - at least one first and one second pressing means (4, 4') for pressing the cleaning element (3) against the coating material, characterized in that the device (1) is designed such that the supply means supplies the cleaning liquid to the first pressing means (4) so that it is dispensed onto the cleaning element (3) via the first pressing means (4) in order to be applied to the coating material, while less cleaning liquid, preferably substantially no cleaning liquid, is supplied to the second pressing means (4') by the supply means.

2. Device according to claim 1, wherein at least one, preferably all, pressing means (4-4''') on the surface which bears against the cleaning element (3) has a material (5) which can absorb, store and release a liquid.

3. Device (1) according to claim 2, wherein the material (5) fleece and / or felt and / or a multi-component material.

4. Device (1) according to claim 2 or 3, wherein the Material (5) is interchangeable.

5. Device (1) according to one of claims 2 to 4, wherein at least one of the pressing means (4-4''') comprises a roller coated with the material (5).

6. Device according to one of the preceding claims, wherein the device is designed so that the pressing force of at least one of the pressing means (4-4'''), preferably all of the pressing means (4-4'''), oscillates.

7. Device according to one of the preceding claims, further equipped with a collecting means (7) for excess cleaning liquid.

8. Apparatus according to claim 7, further comprising means for returning the cleaning liquid collected by the collecting means (7) to the supply means for supplying a cleaning liquid, the apparatus preferably comprising a filter device for cleaning the returned cleaning liquid before application to the coating material.

9. Device according to one of the preceding claims, if dependent on claim 2, further comprising a supply device (8) of gas, preferably compressed air, to the material (5) in order to blow out liquid contained in the material (5).

10. Device according to one of the preceding claims, further comprising a device (9) for drying the coating material.

11. Apparatus according to any one of the preceding claims when dependent on claim 2, further comprising a device (10) for measuring the amount of liquid absorbed in the material (5).

12. Apparatus according to claim 11 when dependent on claim 9 or 10, wherein the means (8) for supplying gas and / or the means (9) for drying the coating material are controlled at least partly based on the output of the means (10) for measuring the amount of liquid.

13. Device (1) according to one of the preceding claims, wherein at least four pressing means (4-4''') are provided.

14. Device according to one of the preceding claims, wherein at least two of the pressing means (4-4''') are movable independently of one another in the direction perpendicular to a direction of travel of the workpiece (20).

15. Device according to one of the preceding claims, wherein the pressing means (4-4''') each have their own pressing device (11) by means of which they can each be individually pressed against the coating material.

16. Device (1) according to one of the preceding claims, further comprising a shaping device for deforming the pressing means (4-4''') so that it adapts to the surface geometry of the workpiece (20).

17. Device (1) according to one of the preceding claims, wherein the cleaning element (3) is provided as a belt which is designed to be moved relative to the coating material, and wherein a device is further provided to determine the amount of unused belt.

18. Plant for finishing a coating material, comprising: a device (1) for cleaning the coating material according to one of the preceding Claims, and a device for patterning, in particular printing, the cleaned coating material.

19. A method for cleaning a coating material, in particular a coating material provided on a workpiece (20), wherein the workpiece (20) preferably consists at least in sections of wood, wood materials or plastic, using a device (1) for cleaning the coating material according to one of claims 1 to 17 and comprising the steps: Bringing about a relative movement between a cleaning element (3) and the workpiece (20) by means of a conveyor unit, Applying a cleaning agent to the cleaning element ( 3 ) and Removing contaminants from the coating material by means of the cleaning element (3).

20. The method according to claim 19, wherein the coating material consists at least in sections of plastic.

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