WO2024223719A1 - Device for cleaning a coating material, system for finishing a coating material, and method for cleaning a coating material - Google Patents

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

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

technical field

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.

State of the art

In the area of furniture and building element production, workpieces made of wood or wood-based materials, for example, are often coated on their surface with a coating material that is typically made of plastic. This coating material can have patterns or, in the course of finishing, receive further patterns in order to, for example, be closer in appearance to that of a wood-based material.

In order to apply such patterns, it is known from the prior art, such as WO 2022/171661 Al, that the strip-shaped coating material 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 any dirt adhering to the coating material, such as fingerprints. This produces a strip-shaped

cleaning material on the coating material This cleaning material absorbs the dirt so that the coating material is cleaned better and can therefore be printed on better.

However, the inventors have noticed that these devices are in need of improvement in that the process speed, the process stability and the need for consumables can still be optimized. The present invention aims to achieve at least some of these goals or to improve the devices mentioned with regard to the above-mentioned parameters.

representation of the invention

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

According to claim 1, a device for cleaning a coating material is defined. Such a coating material can be, for example, an edge band made of plastic, 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 materials or plastic and can in particular consist of a chipboard material.

According to the invention, the device has a cleaning element for removing dirt from the coating material. This is an element by which the dirt can be removed and thus does not stand in the way of subsequent finishing of the coating material. Removal means at least partial removal of the dirt. There is also a supply means for supplying a cleaning liquid. Through this means a cleaning liquid can be supplied which, as will be described in detail later, serves to clean the coating material.

There are also at least a first and a second pressing means for pressing the cleaning element against the coating material. This pressing ensures that the cleaning element is well positioned and adjusted to the coating material, so that the coating material can be cleaned well by the cleaning element.

According to the invention, the device is designed such that the supply means supplies the cleaning liquid to the first pressing means, so that it 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 does not supply any 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 an appropriate design, the consumption of cleaning liquid is reduced, while the advantages of wet cleaning and dry cleaning are combined.

Preferably, at least one and preferably all of the pressing means on the surface that rests 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 absorb fluctuations in the amount of cleaning liquid supplied or fluctuations in the Cleaning element can compensate for or buffer the amount taken.

The material preferably comprises fleece and/or felt and/or is made from a multi-component material of natural or synthetic origin. Such materials are particularly inexpensive and can be used well in industrial environments.

Preferably, the material is replaceable, preferably without tools. This means that it can be easily replaced when it becomes worn, which leads to a consistently high cleaning quality.

Preferably, at least one, preferably all of the pressing means has a roller coated with the material. Such a roller can roll on the coating material, which reduces friction and thus wear on the material. This leads to a consistently high cleaning quality. In this case, the coating is wetted onto the coated roller, which transfers the cleaning fluid to the cleaning element during movement, which thus cleans the workpiece.

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.

It is further preferred that a collecting means for excess cleaning liquid is present. This collecting means can collect 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 necessary above all in the event that the material wears out with the formation of fibers, as is the case with felt and/or nonwoven materials.

It is further preferred that a supply device for gas, preferably purified compressed air, is provided for the material. This serves to blow out liquid in the material and can thus be used to dry the material. The material can also thus be freed of any contaminant particles that may be dissolved in the cleaning liquid.

It is also preferred that a device for drying the coating material is provided. This reduces the time that must elapse before the coating material can be refined. 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.

Furthermore, a device for measuring the amount of liquid that is absorbed in the material is preferably present. Such a device can, for example, measure the electrical conductivity of the material. This makes it possible to monitor how moist the material is, which improves the controllability of the device. At the same time, this makes it possible to also achieve a reduction in the amount of cleaning fluid required.

Furthermore, the gas supply device and/or the device for drying the coating material is controlled at least partially based on the output of the device for measuring the amount of liquid. This can ensure that, for example, in the event that a lot 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.

Preferably, at least four pressing means are provided. This allows a particularly good adaptation of the pressing to the contour of the coating material.

Preferably, at least two of the pressing means can be moved 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 direction of pressure of the pressing means. Due to the corresponding mobility, the pressing means can adapt better to the contour of the coating material.

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

Furthermore, a shaping device is preferably present in order to deform the pressing means in such a way that it adapts to the surface geometry of the workpiece. This leads to a better pressing of the cleaning element and thus to better cleaning.

Preferably, the cleaning element is provided as a belt that is movable with respect to the coating material. In this case, both the coating material and the cleaning element can be displaced or moved. All that matters is the relative movement between these two components.

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.

Furthermore, a system for finishing a coating material is according to the invention, which 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 which is patterned by this device has been cleaned beforehand, the quality of the coating material thus finished is increased.

Furthermore, a method for cleaning a coating material is according to the invention. This coating material is preferably applied to a workpiece which ideally consists at least in sections of wood, wood materials or plastic. A device is used here, as previously mentioned, which serves to clean the coating material. 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 dirt is then removed from the coating material by means of the cleaning element. Such a method is particularly advantageous for the reasons stated with regard to the device claims.

The coating material preferably consists at least in sections, preferably completely, of plastic. Such a coating material is particularly suitable for coating workpieces that are used in the field of furniture production.

Short description of the drawings

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

Figure 2 shows a detailed view of Figure 1 .

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

Detailed description of the drawings

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), moved along the conveying direction indicated by an arrow. The surface that is coated is opposite a belt-shaped cleaning element 3 that is mounted on rollers 2 and can be moved over these. The up and down rolling movement of the rollers 2 moves the cleaning element 3 relative to the workpiece 20 and thus removes dirt. In this 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.

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

Press the cleaning element 3 against the workpiece 20 .

In the upstream first pressing 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 band made of material, which can absorb a fluid and release it onto the coated surface of the workpiece 20. Due to the relative movement between the workpiece 20 and the cleaning element 3, dirt that is provided on the coating of the workpiece 20 is removed.

For the supply of 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 with a supply unit still exists.

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 pressing against the cleaning element 3. The felt material 5 is an example of a material which can absorb a liquid (such as a cleaning liquid), as defined in the claims.

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.

Further downstream there is also a device 9 for drying the workpiece, which, as already mentioned, can have 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'.

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

Below the felt material 5 there is a collecting tray 7 to collect excess cleaning liquid that comes from the felt material 5. This liquid can be drained into a separate container or it can be fed back into the channels 6, but in almost all cases the cleaning liquid must be filtered. is necessary because felt materials and other types of textiles in particular release fibres .

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 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 is used for dry cleaning, in order to supply the second pressing element 4' with gas from there.

Cleaning fluid which is transferred via the cleaning element 3.

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 clocked. In a clocked 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 moved back 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.

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

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

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 also be achieved. However, it is also conceivable that the felt has different thicknesses and/or densities in the z-direction, which is the upward or downward direction, which in turn has an influence on the buffering effect for fluid.

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 special areas of the workpiece surface. For example, two of the pressing elements 4-4''' can be used for wet cleaning, with the other two pressing elements 4-4''' being used for dry cleaning. The idea here is that, for example, the first and second pressing elements 4, 4' in the direction of travel are used for wet cleaning, while the third and fourth pressing elements 4'', 4''' are used for dry cleaning. Alternatively, the first and third pressing elements 4, 4'' can be used for wet cleaning, while the second and fourth pressing elements 4', 4''' are used for dry cleaning. In this case, the respective pressing elements used for wet cleaning are subjected to the same cleaning fluid.

In such an embodiment, it is envisaged 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.

Alternatively, it is also possible that only two pressing elements 4-4 ' ' ' are 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 makes it possible to clean workpieces 20 with different geometric characteristics.

By the invention as described in the first and second embodiments, the consumption of Cleaning fluid and cleaning agents in the form of tape can be reduced as they can also be dosed more precisely.

Claims

1. Device (1) for cleaning a Coating material, in particular a coating material provided on a workpiece (20), the workpiece (20) preferably consisting 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 a first and a 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 essentially 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 rests 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 such that the pressing force of at least one of the pressing means (4-4'''), preferably of all 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. Device according to 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 device (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. Installation 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. Method for cleaning a coating material, in particular a coating material provided on a workpiece (20), the workpiece (20) preferably consisting 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 with the steps: Inducing 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.