Device and method for laser coating workpieces

Abstract

The invention relates to a device (1) for laser coating workpieces (2), the device having a working chamber (3) in which a laser-coating unit (4) with a laser (5) and a gas particle supply means (6) and at least two working positions (7, 8) for laser coating workpieces (2) are arranged, wherein, for each of the working positions (7, 8), the device (1) has a changeover device (9, 10) for loading the working positions (7, 8) with workpieces (2), and has a laser-positioning drive (11) configured to move the laser (5) of the laser-coating unit (4) between the working positions (7, 8) in order to work on workpieces (2) at each of the at least two working positions (7, 8).

Description

[0001] PC 24 0697 J 18 . November 2024

[0002] Device and method for laser coating of workpieces

[0003] The invention relates to a device and a method for laser coating of workpieces, in particular rotationally symmetrical workpieces, such as brake discs.

[0004] Laser coating involves applying a coating material to a workpiece. The coating material is typically supplied to the workpiece as a powder consisting of particles, via a gas stream. The gas serves as a protective gas and transport medium and can be, for example, an inert gas such as argon.

[0005] The coating material is liquefied using a laser beam and applied to the surface of the workpiece. This type of laser coating process is also known as laser cladding. The coating material provides certain properties, such as corrosion protection or wear resistance, which the base material of the workpiece does not possess. Through this cladding process, the base material of the workpiece and the coating material form a cohesive bond.

[0006] The main cost driver when implementing this process in mass production is usually the coating material. The less coating material used or lost during the process, the more cost-effective the process becomes.

[0007] For process stability during the execution of the procedure, a particle-gas flow that is as constant as possible is crucial. Once a constant particle-gas flow for supplying the coating material has been established, the gas flow should be PC 24 0697 J 2 / 20 18 November 2024

[0008] cannot be interrupted, as it is difficult to quickly rebuild a constant particle-gas flow.

[0009] Currently, after a workpiece is coated, the laser used to generate a laser beam for melting the coating material is deactivated. However, the particle gas flow is maintained to save the time required to establish a constant particle gas flow.

[0010] If the workpieces are rotationally symmetrical, it can be advantageous to accelerate them to a specific rotational speed for laser coating, which can further increase the waiting time before the coating process can be resumed. During this waiting time, valuable coating material is lost if the powder gas flow is maintained.

[0011] The longer the workpiece replacement takes, the more coating material is lost and the higher the costs of carrying out the laser coating process.

[0012] Especially in mass production, the costs for the coating material lost due to the chosen procedure have a negative impact on the unit costs.

[0013] The object of the invention is therefore to create a method and a device for laser coating of workpieces that enable more efficient laser coating of workpieces and in particular reduce the amount of coating material lost.

[0014] To solve the problem, a device for laser coating of workpieces is first proposed, which has a working area in which a laser coating unit with a PC 24 0697 J 3 / 20 18 . November 2024

[0015] The device comprises a laser and a gas particle feeder, and at least two processing positions for laser coating workpieces. According to the invention, the device has, for each of the processing positions in the working area, a changer device for loading the processing positions with workpieces and a laser positioning drive configured to move the laser of the laser coating unit between the processing positions for processing workpieces at each of the at least two processing positions. The movement of the laser between the processing positions can occur along a movement axis. The movement axis can preferably be a linear axis.

[0016] Within the device's workspace, two processing positions are available for machining workpieces. While the laser of the laser coating unit is used at one processing position to perform laser coating of a workpiece, another workpiece can already be held at the other processing position in the workspace for laser coating. As soon as the laser coating of the first workpiece is completed, the laser of the laser coating unit can be moved directly to the second processing position using the laser positioning drive to perform laser coating of the workpiece already held at the other processing position.The time during which coating material is lost by maintaining a particle-gas flow before another workpiece can be laser-coated is minimized in the device according to the invention to the time the laser needs to change from one processing position to another. Once the laser has changed to the other processing position, PC 24 0697 J 4 / 20 18 November 2024.

[0017] the coating of the other workpiece, which is held at the other processing position, can be applied directly.

[0018] In this context, it is particularly advantageous if the distance between the processing positions within the workspace is as small as possible. The distance between the processing positions can be chosen such that the distance between workpieces arranged therein is smaller than a dimension of a workpiece to be coated that can be measured in the coating plane, in particular than the diameter of the workpiece to be coated. In this way, the laser's transfer path between the processing positions is minimized, and the time period during which a gas-particle flow for material supply is maintained and coating materials can be lost is largely reduced.

[0019] Preferably, the gas particle feeder can be moved along with the laser using the laser positioning unit. The gas particle feeder can be configured to supply a gas particle stream. For example, an inert gas such as argon can be used. The gas acts as a transport and protective medium for supplying particles of the coating material.

[0020] In one version of the device, the changing devices are designed as rotary indexing tables. The use of rotary indexing tables as changing devices enables rapid workpiece changes and reliable execution of the changeover processes.

[0021] Rotary indexing tables also require comparatively little floor space and are therefore advantageous for space-saving device designs. PC 24 0697 J 5 / 20 18. November 2024

[0022] In one embodiment of the device, the at least two processing positions are arranged side by side in the work area. This facilitates the fastest possible transfer of the laser from one processing position to the other. In another embodiment of the device, the at least two processing positions are arranged side by side in the device's work area in such a way that no functional unit of the device is located between the processing positions.

[0023] Furthermore, it is possible that at least two processing positions can be reached by a linear movement of the laser.

[0024] The device can have a workpiece drive for each processing position. The workpiece drive can be used to position workpieces relative to the laser during laser coating. In one embodiment of the device, the workpiece drives at each processing position are designed as rotary drives. A device equipped in this way is particularly suitable for laser coating rotationally symmetrical workpieces, such as brake discs. In another embodiment of the device, which is designed for laser coating workpieces that are not rotationally symmetrical, the workpiece drive can be a linear drive.

[0025] The laser can be moved along a secondary axis of movement by means of the laser positioning drive, which is oriented transversely or perpendicularly to the aforementioned axis of movement of the laser, along which the laser can be moved between the at least two processing positions in the work space.

[0026] This secondary axis of movement can be used as a second axis of movement PC 24 0697 J 6 / 20 18 November 2024

[0027] can be referred to as the first axis of movement, while the previously mentioned axis of movement can be referred to as the first axis of movement.

[0028] Each processing position can be assigned a loading position and / or an unloading position. The loading position and / or the unloading position can each be located outside the working area of ​​the device.

[0029] Each tool changer can furthermore have at least three clamping positions for workpieces. Thus, it is possible that one clamping position of the tool changer is arranged in one of the machining positions, while of the other two clamping positions of the tool changer, one is arranged in the loading position and the other in the unloading position.

[0030] The device may also include an extraction system. This system can be designed to extract particles that are not bonded to the surface of the workpieces being coated, as well as gas, from the device's working area. This reduces or completely eliminates contamination of the device's working area and any potential health risks to people in the vicinity. This is particularly important when coating material is used in the form of particles that are respirable due to their size.

[0031] In a particularly preferred, because space-saving, integration of the extraction device, it is provided that each device has an extraction channel that extends along a rotation axis of each changing device into the working space.

[0032] The device may also include at least one protective enclosure for the machining positions. (PC 24 0697 J 7 / 20 18. November 2024)

[0033] A protective enclosure prevents the unintentional escape of laser beams and coating material from the workspace. The enclosure can, for example, consist of a stationary housing section and, for each of the changeover devices, a housing section that moves with the respective changeover device. The moving housing section can have cutouts that allow access to the workpiece clamping points on the changeover device. Overall, this creates a particularly safe protective enclosure that effectively prevents the escape of coating material particles and / or laser beams from the workspace.

[0034] The device may further include a control unit which is configured to control the laser positioning drive and / or the aforementioned workpiece drives depending on the respective impact position of a laser beam generated by the laser on the workpiece.

[0035] Especially with rotationally symmetrical workpieces that are rotated during coating, it can be advantageous to control the rotational speed at which the workpiece to be coated is driven, depending on the point of impact of the laser beam generated by the laser on the workpiece.

[0036] If the laser beam generated by the laser strikes the workpiece in a position close to the workpiece's axis of rotation, it may be advantageous to rotate the workpiece at a higher speed than if the laser beam were directed onto the workpiece at a radially more distant position for laser coating. This allows for laser coating to be performed at constant coating rates, thus ensuring uniform application of the coating material. PC 24 0697 J 8 / 20 18 November 2024

[0037] to apply a rotationally symmetrical workpiece.

[0038] The device may have a user interface. The user interface allows, for example, adjustments to the device settings, influences its control, and / or monitoring of the process performed on the device. The device, and in particular the user interface, may include, for example, a display on which operating parameters of the device can be shown and / or settings on the device can be adjusted.

[0039] The device can include a network interface through which the device, and in particular its control unit, can be connected to a network. This makes it possible to connect the device to a higher-level control computer and / or integrate it into a production network. Data and / or control signals can also be transmitted to the device, and in particular to its control unit, via the network interface. Preferably, the network interface is configured for bidirectional communication. The network interface can enable remote control and / or remote monitoring of the device.

[0040] To solve the problem, a method for laser coating of workpieces, in particular rotationally symmetrical workpieces, such as brake discs, is also proposed, which is preferably carried out using a device according to one of the claims directed to such a device.

[0041] According to the invention, the means and features of the independent claim directed to such a method are proposed to solve the problem. Specifically, it is provided that a first workpiece is produced in a first PC 24 0697 J 9 / 20 18 November 2024

[0042] A processing position is laser coated with a laser coating unit, wherein a second workpiece is held ready for processing at a second processing position before the laser coating of the first workpiece is completed, and wherein the laser of the laser coating unit is moved to the second processing position after laser coating of the first workpiece in order to laser coat the workpiece held there.

[0043] The second workpiece can, for example, already be held in the second processing tool while the first workpiece is still being laser-coated in the first processing position.

[0044] When carrying out the process, the laser can preferably be moved from one processing position to another together with a gas particle feeder through which the coating material is supplied.

[0045] In one implementation of the process, a gas particle stream is maintained to supply coating material when the laser changes from one processing position to another.

[0046] The workpieces can be moved, in particular rotated, during laser coating using a workpiece drive. In this way, it is possible to generate a motion component of the relative movement of the laser to the workpiece, as required for laser coating, by moving the workpiece itself.

[0047] A workpiece located at one machining position can be accelerated to a target speed, while another workpiece is still being machined at the other machining position. PC 24 0697 J 10 / 20 18 November 2024

[0048] The laser coating process is carried out. In this way, it is possible to minimize unproductive downtime during the laser coating process, particularly for brake discs or other rotationally symmetrical workpieces. Even before the laser coating of one workpiece is complete, the other workpiece can already be accelerated to its target speed, so that the laser coating of the other workpiece can begin immediately after the laser coating of the first workpiece is complete.

[0049] The invention is described in more detail below with reference to an exemplary embodiment, but is not limited to this embodiment. Further exemplary embodiments result from combining the features of one or more claims with one another and / or from combining one or more features of the exemplary embodiment. The figures show:

[0050] Fig. 1 shows a schematic side view of a device for laser coating of workpieces as well as

[0051] Fig. 2 is a top view of the device shown in Figure 1 to illustrate the protective housing of the device.

[0052] The figures show a device for laser coating of workpieces 2, namely brake discs, designated as a whole by 1.

[0053] The device 1 has a working chamber 3 in which a laser coating unit 4 with a laser 5 and a gas particle feeder 6 is arranged. The gas particle feeder 6 is configured to supply the workpieces 2 with a coating material in the form of particles for laser coating by means of a gas stream. PC 24 0697 J 11 / 20 18 November 2024

[0054] Within the working area 3 of the device 1, two processing positions 7 and 8 are also arranged, in which workpieces 2 can be held for laser coating in the working area 3. At one processing position 7, one side of the workpieces 2 is laser coated. At the other processing position 8, the other side of the workpieces 2 is laser coated.

[0055] The device 1 has a changeover device 9 and 10 for each of the machining positions 7 and 8. The changeover devices 9 and 10 are designed as rotary indexing tables and are configured to load the two machining positions 7 and 8 with workpieces 2.

[0056] Furthermore, the device 1 has a laser positioning drive 11. The laser positioning drive 11 is configured to move the laser 5 of the laser coating unit 4 and also the gas particle feed 6 along a movement axis 12 between the processing positions 7 and 8 in order to laser-coat workpieces 2 at each of the two processing positions 7 and 8. The laser coating unit 4 moves the gas particle feed 6 along with the laser 5. The area in which the laser 5 and the gas particle feed 6 can be moved within the working space 3 is shown in hatching in Figure 2.

[0057] The two processing positions 7 and 8 of the device 1 are arranged directly next to each other in the working area 3 of the device 1. Both processing positions 7 and 8 can be approached by a linear movement of the laser 5. The linear movement of the laser 5 takes place along the axis of movement 12.

[0058] Each machining position 7 and 8 is further equipped with a workpiece drive 13, in this case a rotary drive. The workpiece drives 13 serve to drive the PC 24 0697 J 12 / 20 18. November 2024

[0059] rotationally symmetrical workpieces 2, namely the brake discs, to be rotated for laser coating and thereby to generate a motion component of a relative movement between laser 5 and workpiece 2 desired for laser coating of the workpieces 2.

[0060] One movement component required for the laser coating of the workpieces 2 is caused by a movement of the laser 5, while the other movement component for coating the workpieces 2 is caused by the workpiece drives 13.

[0061] With the aid of the laser positioning drive 11, the laser 5 can also be moved along a secondary axis of movement, which is oriented transversely or perpendicularly to the axis of movement 12, if required. This allows workpieces 2 that are not rotationally symmetrical to be laser-coated using the device 1.

[0062] Each processing position 7 and 8 is assigned a loading position 14 and an unloading position 15. The loading positions 14 and the unloading positions 15 are each located outside the working area 3 of the device 1. At the loading positions 14, the exchange devices 9 and 10 can be loaded with workpieces 2. At the unloading positions 15, laser-coated workpieces 2 can be removed from the exchange devices 9 and 10.

[0063] Each of the two exchange devices 9 and 10 shown in the figures has three clamping positions 16 for workpieces 2. One workpiece 2 can be clamped at each clamping position 16.

[0064] The device 1 further comprises a suction device 17. The suction device 17 has at least one suction channel 18 for each of the interchangeable devices 9 and 10, which extends along PC 24 0697 J 13 / 20 18. November 2024

[0065] The rotation axis 19 of the respective exchange devices 9 and 10 is guided into the working chamber 3 of the device 1. Excess particles of the coating material that did not bond to the surface of the workpieces 2 during laser coating, along with the gas, can be extracted from the working chamber 3 of the device 1 via the extraction channels 18.

[0066] The device 1 has a protective housing 20 for the machining positions 7 and 8. The protective housing 20 comprises a stationary housing part 21 and two housing parts 22 which are movable together with the interchangeable devices 9 and 10.

[0067] The device 1 is equipped with a control unit 23, which is designed to control the laser positioning drive 11 and the workpiece drives 13 depending on the respective impact position of a laser beam generated by the laser 5 on the workpiece 2.

[0068] The control unit 23 is also connected to a user interface 24 and a network interface 25. The user interface 24 includes a display 26, which can be used to output operating information of the device 1 and / or to make settings on the device 1 and / or to query its operation.

[0069] The previously described device 1 is configured to carry out the following method for laser coating workpieces 2. In this process, a first workpiece 2 is laser-coated in a first processing position 7 using the laser 5 of the laser coating unit 4, while a second workpiece 2 is held ready for processing at the second processing position 8. After the first workpiece 2 has been laser-coated, the laser 5 of the laser coating unit 4 is moved to the second processing position 8 to coat the workpiece 2 held there. PC 24 0697 J 14 / 20 18 November 2024

[0070] Laser coating. Before the laser coating of a workpiece at the first processing position 7 is completed, another workpiece 2 is already ready for laser coating at the second processing position 8.

[0071] A gas particle stream for supplying coating material is maintained when the laser 5 changes from one processing position 7 to the other processing position 8.

[0072] The workpieces 2 are moved, specifically rotated, by a workpiece drive 13 during laser coating. In this way, a movement component is introduced for the laser coating of the workpieces 2 by the respective workpiece drive 13.

[0073] A workpiece 2 located in processing position 7 or 8 is accelerated to a target speed before the laser coating of the workpiece 2 is completed at the other processing position. This allows the time that the workpiece 2 spends waiting for its laser coating at the second processing position 8 to be used to accelerate the workpiece 2 to the target speed.

[0074] / Reference list PC 24 0697 J 15 / 20 18 November 2024

[0075] Reference symbol list

[0076] 1 Device for laser coating

[0077] 2 workpieces

[0078] 3 workroom

[0079] 4 laser coating units

[0080] 5 lasers

[0081] 6 Gas particle feed

[0082] 7 first processing position

[0083] 8 second processing position

[0084] 9 first changing device

[0085] 10 second changing device

[0086] 11 Laser positioning drive

[0087] 12 axes of movement for 5

[0088] 13 Workpiece drive

[0089] 14 loading positions

[0090] 15 Unloading position

[0091] 16 clamping positions

[0092] 17 Extraction device

[0093] 18 Extraction channel

[0094] 19 Rotation axis

[0095] 20 Protective enclosure

[0096] 21 fixed housing part

[0097] 22 movable housing part

[0098] 23 Control unit

[0099] 24 User interface

[0100] 25 Network interface

[0101] 26 Display

[0102] / Claims

Claims

PC 24 0697 J 16 / 20 November 18, 2024 Claims 1. Device (1) for laser coating of workpieces (2) with a working space (3) in which a laser coating unit (4) with a laser (5) and a gas particle feed (6) and at least two processing positions (7, 8) for laser coating of workpieces (2) are arranged, wherein the device (1) has for each of the processing positions (7, 8) a changer device (9, 10) for loading the processing positions (7, 8) with workpieces (2) and a laser positioning drive (11) which is configured to move the laser (5) of the laser coating unit (4) for processing workpieces (2) at each of the at least two processing positions (7, 8), in particular along an axis of movement (12) between the processing positions (7, 8).

2. Device (1) according to the previous claim, wherein the gas particle feeder (6) is movable along with the laser (5) by means of the laser positioning unit (11) and / or wherein the gas particle feeder (6) is configured to supply a gas particle stream.

3. Device (1) according to one of the preceding claims, wherein the changing devices (9, 10) are designed as rotary indexing tables.

4. Device (1) according to one of the preceding claims, wherein the at least two processing positions (7, 8) are arranged next to each other and / or can be approached by a linear movement of the laser (5) with the laser (5).

5. Device (1) according to any one of the preceding claims, wherein PC 24 0697 J 17 / 20 November 18, 2024 the device (1) has a workpiece drive (13) for each machining position (7,8), in particular a rotary drive and / or a linear drive.

6. Device (1) according to one of the preceding claims, wherein the laser (5) is movable with the laser positioning drive (11) along a secondary axis of movement which is oriented transversely or perpendicularly to the axis of movement (12).

7. Device (1) according to one of the preceding claims, wherein each machining position (7, 8) is / are assigned a loading position (14) and / or an unloading position (15) and / or wherein each changing device (9, 10) has at least three clamping positions (16) for workpieces (2).

8. Device (1) according to one of the preceding claims, wherein the device (1) has a suction device (17), in particular wherein the suction device (17) has at least one suction channel (18) for each changer device (9, 10) which is guided into the working space (3) along a rotation axis (19) of the respective changer device (9, 10).

9. Device (1) according to one of the preceding claims, wherein the device (1) has at least one protective housing (20) for the machining positions (7, 8), in particular wherein the protective housing (20) has a fixed housing part (21) and for each changing device (9, 10) a housing part (22) that can move with the respective changing device (9, 10).

10. Device (1) according to one of the preceding claims, wherein the device (1) has a control unit (23) configured to control the laser positioning drive (11) PC 24 0697 J 18 / 20 November 18, 2024 and / or to control the workpiece drives (13) depending on the impact position of a laser beam generated with the laser (5) on the workpiece (2).

11. Device (1) according to one of the preceding claims, wherein the device (1) has a user interface (24), in particular with a display (26), and / or a network interface (25).

12. Method for laser coating of workpieces (2), in particular brake discs, preferably using a device (1) according to one of the preceding claims, wherein a first workpiece (2) is laser coated in a first processing position (7, 8) by means of a laser (5) of a laser coating unit (4), wherein a second workpiece (2) is held ready for processing at a second processing position (8, 7) before the laser coating of the first workpiece (2) is completed, and wherein the laser (5), preferably together with a gas particle feeder (6), is moved to the second processing position (8, 7) after laser coating of the first workpiece (2) in order to laser coat the workpiece (2) held there.

13. Method according to the previous claim, wherein a gas particle flow is maintained for the supply of coating material when changing the laser (5) of the laser coating unit (4) from one processing position (7,8) to the other processing position (8,7).

14. Method according to one of the preceding claims, wherein the workpieces (2) are moved, in particular rotated, by a workpiece drive (13) during laser coating.

15. Method according to any one of the preceding claims, wherein a PC 24 0697 J 19 / 20 November 18, 2024 The workpiece (2) located in one processing position (7,8) is accelerated to a target rotational speed before the laser (5) is moved to the other processing position (7,8) and / or the laser coating of the workpiece (2) at the other processing position (7,8) is completed.

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