Method for adjusting paint guns

Abstract

The invention relates to a method for adjusting one or more spray guns (10) of an automatic painting machine, wherein removable laser devices (15) are placed on the spray guns (10) in such a way that the emitted laser beams lie directly in the spray axis of the spray guns (10), wherein the spray guns (10) are aligned with the laser beams on a workpiece to be subsequently painted in the automatic painting machine or on an image, a stencil or a marking, and wherein the laser devices (15) are removed from the spray guns (10) after the alignment has been carried out.

Description

[0001] The invention relates to a method for adjusting paint guns on automatic painting machines.

[0002] In the field of paint finishing, automated painting systems such as flatbed sprayers, lift-and-lower units, and strip sprayers are used for the automated and uniform application of paints to various surfaces. Flatbed sprayers are used to coat large workpieces with paint. Typical applications include furniture manufacturing (e.g., cabinet doors, worktops), the automotive industry (e.g., body parts), and the coating of metal, wood, or plastic panels. Lift-and-lower units are used, for example, in the production of windows and doors. Strip sprayers are specialized for coating narrow, elongated workpieces such as strips, frames, or profiles. Typical applications include coating door and window frames, baseboards or decorative moldings, and profiles made of wood, plastic, or metal.

[0003] Both types of automatic painting machines have a spray booth, a conveyor system to transport workpieces through the machine, one or more spray guns to apply the paint to the surface of the workpiece, a paint preparation system to supply the paint to the spray guns, an extraction device and, if necessary, a drying system.

[0004] Surface spraying machines aim for a uniform paint application regardless of the workpiece size. With strip spraying machines, the focus is on precise paint application on narrow or complexly shaped workpieces. Low material waste and high production speed are the goals of both types of spraying machines. To achieve these objectives, reproducible and precise automatic control of the spray guns is required, both with regard to the position and orientation of the spray guns and the paint dispensing.

[0005] In practice, problems frequently arise in precisely this context. Specifically, it is often not easy to determine the exact point of a spray gun in existing automated systems. This poses problems for users not only when setting up a particular workpiece, but also when readjusting misaligned guns, checking repeatability, and transferring settings between different automated systems.

[0006] Prior art includes, for example, EP 0 990 468 A1, US 5,598,972 A, and US 7,244,464 B2, handheld spray guns that indicate the optimal distance to the workpiece to the user by means of two laser beams traveling at an angle to each other. US 5,741,096 A and DE 33 33 428 A1 disclose stationary drilling and riveting machines, respectively, which have a laser-assisted positioning aid to indicate the drilling or riveting point on a workpiece to the user in advance, thus enabling precise workpiece positioning. However, none of the solutions described are suitable for determining the precise alignment of spray guns during the presetting of automated painting systems.

[0007] The object of the present invention is to provide a solution which at least partially overcomes the disadvantages shown and makes it easy to determine exactly where the spray guns of a painting machine are pointing, and which can also be applied to existing machines.

[0008] Against this background, the invention relates to a method for adjusting one or more spray guns of an automatic painting machine, wherein removable laser devices are placed on the spray guns in such a way that the emitted laser beams lie directly in the spray axis of the spray guns, wherein the spray guns are aligned with the laser beams on a workpiece to be subsequently painted in the automatic painting machine or on an image, a stencil or a marking, and wherein the laser devices are removed from the spray guns again after the alignment has been carried out.

[0009] The adjustment can be a pre-adjustment before painting one or more identical workpieces, or a readjustment during a series of paintings of several identical workpieces.

[0010] The present invention proposes that the laser beams run directly along the spray axis of the spray guns, resulting in very high precision regardless of the distance between the spray gun and the workpiece. This is only feasible with a detachable solution, as the laser and the spray gun could not be positioned on the same axis with a fixed solution. For reasons of cost and flexibility, a detachable solution is advantageous in any case and can, in particular, be used on existing systems without requiring costly retrofitting. The method is equally suitable for use with air-atomizing spray guns and with atomization without air assistance.

[0011] The solution according to the invention can utilize the design of typical spray guns used in existing automated painting systems. Preferably, the laser devices are mounted on the tips of the spray guns. Suitable mounting structures can be present there.

[0012] In one embodiment, the laser devices are attached to the spray guns by means of a reversibly detachable positive-locking or force-locking connection. Examples include, in particular, screw, plug, and snap-fit ​​connections. In another embodiment, before attaching the laser device, at least one non-destructively removable part of the spray gun is removed, and either the removed part is used to attach the laser device, or the laser device is attached to the exposed mounting contour of the spray gun. In the former case, for example, a retaining nut can be unscrewed, a component held by the retaining nut, such as an atomizer unit of the nozzle, can be removed, and the laser device can then be attached in place of the component using the same retaining nut.In the latter case, the laser device can, for example, have a counter contour corresponding to the counter contour of the part being removed, such as an internal thread corresponding to an internal thread of the part being removed. This counter contour can be standardized or custom-designed. Examples of such parts include a retaining ring or a cap nut of the spray gun. Such connections offer the advantage of particularly precise axial alignment of the laser. In another example, the laser device can include an axial sleeve on its rear side that can be fitted precisely over the tip of the spray gun. Conversely, the laser device can have an axial sleeve or other axially protruding contour on its rear side that can be inserted precisely into an axial recess at the tip of the spray gun. Such connections offer the advantage of a particularly wide range of applications.

[0013] When the laser device is mentioned in this context, it includes the possibility that the laser device has a separate mount that is attached to the spray gun, and to which the laser unit is then attached. In some embodiments, the use of a mount may even be preferred, as it allows the use of a single, identical laser unit with different spray guns. The component costs of the mount are significantly lower than the component costs of the laser unit.

[0014] The laser device can emit a line, cross, circle, or point laser beam and optionally incorporate diffractive optical elements. Distance measurement is also possible with widening circular lasers. Colors can be, for example, green, blue, or red. This aspect can be optimized depending on the application and the surface color.

[0015] In one embodiment, the laser device comprises a second laser device whose emitted laser beam runs parallel or at an angle to the laser beam lying directly in the spray axis of the paint guns, in order to be able to detect, for example, distances or rotational positions.

[0016] Further details and advantages of the invention will become apparent from the exemplary embodiments described below with reference to the figures. The figures show: Fig. 1: A schematic representation of a paint gun with a laser device mounted according to the invention in a first embodiment. Fig. 2: A schematic representation of a paint gun with a laser device mounted according to the invention in a second embodiment.

[0017] Fig. 1 Figure 1 shows a schematic representation of a spray gun 10 as part of an automated painting system. Not shown are the other components of the automated painting system, which, in addition to the spray guns 10, may include a spray booth, a conveyor system for transporting workpieces through the system, a paint preparation system for supplying the paint to the spray guns, an extraction system, and, if necessary, a drying system. The automated painting system can, for example, be designed as a surface spraying system for the automated and uniform application of paints to various surfaces and may include one or more spray guns as shown, which are moved automatically in response to control commands by means of a holder 11, for example, a robot arm.

[0018] In the given example, the spray gun 10 is depicted as an air-atomizing gun and is constructed in a conventional manner. Its central components include a holder 11, a spray gun with a housing 14 and, for example, a nozzle 13 designed as an air-atomizing nozzle, as well as a material line 12 for supplying the paint to the nozzle 13. If configured as an air-atomizing nozzle, a compressed air source is also connected, though not shown in detail. The air-atomizing nozzle itself can include a material nozzle for the paint exit and an air cap that directs compressed air around the material stream, atomizing and shaping it.

[0019] The housing 14 of the spray gun includes at its front tip, i.e., at the end face facing the spray direction, a union nut 16 screwed axially to the spray axis, which is in a Fig. 1 The spray gun, in its basic state (not shown), holds an atomizing unit. The internal thread of the union nut corresponds to an external thread on the remaining housing parts. Both threads spiral around the spray axis.

[0020] In the inventive method, in which the alignment of the spray gun 10 to a workpiece to be painted (not shown) is finely adjusted, this retaining nut 16 is unscrewed from the housing 14, the atomizer unit is removed and replaced by a laser device 15, and the laser device 15 is then reattached using the retaining nut 16. The laser device 15 comprises several parts, namely the holder 15a and the laser unit 15b. The holder 15a is a component that ensures compatibility between a laser unit 15b of a specific design on the one hand and a spray gun 10 with a specific housing 14 configuration on the other. It can be a cost-effectively manufactured plastic part. The laser unit 15b emits the laser beam and is connected to the holder 15a by means of a suitable connection, which in the example shown is a plug connection.

[0021] In the assembled state of the laser device 15, which is in Fig. 1 As shown, the fine adjustment of the spray gun 10's alignment to the workpiece is carried out. This can be done on the workpiece itself or on a replica of the workpiece, a template, or a marking. Once this fine adjustment has been completed and the control routine of the automatic paint system has been adjusted accordingly, the laser device 15 is rotated again and the atomizer unit is attached.

[0022] The components are then painted. This process can be repeated if a deviation is detected in production, or routinely after a certain period of time or number of painting operations.

[0023] Fig. 2 Figure 1 shows a schematic representation of a spray gun 10 as part of an automated painting system, in which the invention is implemented in an alternative manner, namely by the laser device 15 being positively fitted onto the spray gun 10. The same reference numerals are used for identical parts as in Figure 1. Fig. 1 .

[0024] One difference from the embodiment of the Fig. 1 The difference lies in the way the laser device 15 is attached to the spray gun 10. Specifically, in the exemplary embodiment, the Fig. 2 The laser device 15, with its holder 15a, which has the form of an axial sleeve, is provided to be inserted over a corresponding counter contour at the tip of the spray gun 10. Suitable locking devices may be provided on the holder 15a to achieve axial locking.

[0025] In summary, the invention provides a method for adjusting the spray guns of an automatic paint system, in which laser beams are used for the adjustment, the special feature being that the use of laser attachments creates, firstly, compatibility with existing automatic paint systems and, secondly, the possibility of the laser beams running directly in the spray axis of the spray guns and thus a very high adjustment precision.

Claims

1. Method for adjusting one or more spray guns (10) of an automatic painting machine, wherein removable laser devices (15) are placed on the spray guns (10) such that the emitted laser beams lie directly in the spray axis of the spray guns (10), wherein the spray guns (10) are aligned with the laser beams on a workpiece to be subsequently painted in the automatic painting machine or on an image, a stencil or a marking, and wherein the laser devices (15) are removed from the spray guns (10) after the alignment has been carried out.

2. Method according to claim 1, characterized by the fact that The setting is a preset adjustment made before painting one or more identical workpieces.

3. Method according to claim 1, characterized by the fact that The setting involves a readjustment during a series of painting processes on several identical workpieces.

4. Method according to any one of the preceding claims, characterized by the fact that Before attaching the laser devices (15), at least one non-destructively removable part of the paint guns (10) is removed and either the removed part is used to attach the laser device (15) or the laser device (15) is attached to a mounting contour of the paint gun (10) that is exposed by removing the part.

5. Method according to claim 4, characterized by the fact that the part that can be removed without damage is a retaining ring or a union nut (16).

6. Method according to any one of the preceding claims, characterized by the fact that the laser devices (15) are attached to the paint guns (10) by means of reversibly detachable form-fit or force-fit connections.

7. Method according to claim 6, characterized by the fact that The reversibly detachable connections are screw connections.

8. Method according to claim 6, characterized by the fact that the laser devices (15) have an axial sleeve or other axially protruding contour on the rear side, which is inserted precisely into an axial recess at the tip of the paint gun (10) for fastening.

9. Method according to claim 6, characterized by the fact that The laser device (15) has an axial sleeve on the back which is fitted precisely over the tip of the paint gun (10) for attachment.

10. Method according to claim 8, characterized by the fact that the laser device (15) has an axial sleeve or other axially protruding contour on the rear side which can be inserted precisely into an axial recess at the tip of the paint gun (10).

11. Method according to any of the preceding claims, characterized by the fact thatthe laser devices (15) are designed in two or more parts and comprise a laser device (15b) and a holder (15a), wherein the holders (15a) are attached to the paint guns (10) and the laser devices (15b) are attached to the holders.

12. Method according to any one of the preceding claims, characterized by the fact that the laser devices (15) shall include at least one further laser device whose emitted laser beam runs parallel or at an angle to the laser beam lying directly in the spray axis of the paint guns (10).

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