Method for machining a workpiece and a device for carrying out

Abstract

Method for processing a workpiece (2) using a tool (9) which is a welding robot with a laser, for repairing a surface (4) of the workpiece (2) with the laser by welding with welding wire, wherein the welding wire is fed to the tool (9) with a wire feeder, the method comprising the following steps: - Taking a picture (7) of the area to be processed or the defect (5) of the workpiece (2) with a camera (6), - Display of the image (7) on an imaging element (8), which is a touchpad or touchscreen; - Marking the area to be worked on or the defect (5) by lines affixed to the workpiece (2); - Controlling the tool (9) with a control element (10), wherein the control element (10) is a pen containing a position sensor and a pressure sensor, - wherein a position of the tool (9) relative to the workpiece (2) is controlled via a position of the control element (10) relative to the imaging element (8), - and wherein a pressure exerted by the control element (10) on the imaging element (8) controls the wire feed to the tool (9), - wherein the control element (10) is connected to a control of the tool (9), - wherein the controller is configured to receive data from the control element (10) from the position sensor and the pressure sensor, which are executed by the controller to control the tool (9).

Description

[0001] The invention relates to a method for machining a workpiece using a tool according to the preamble of claim 1 and a corresponding device according to the preamble of claim 8. State of the art

[0002] Such methods for processing a workpiece using a tool, such as a laser, are known in a wide variety of forms and designs. Lasers can be used in many ways for workpiece processing, such as cutting workpieces, hardening workpiece surfaces, or joining workpieces by welding. In this processing method, it is often necessary to observe the workpiece area to be processed using an observation device, such as a microscope, in order to guide the laser beam used for processing across the workpiece with sufficient accuracy. If the welding is carried out in the form of cladding, where a welding wire must be placed over the area to be welded, the use of such an observation device is practically indispensable to guide the welding wire with sufficient precision.

[0003] German patent DE 101 57 893 B4 describes such a method. This involves a laser processing device with an optical observation device for monitoring the area of ​​a workpiece being processed. The disadvantage of this invention is that the user must be present at the laser processing device to monitor the area of ​​the workpiece being processed during the operation.

[0004] Crucially, in many cases the laser must operate at a power level that results in impermissible radiation exposure for personnel. For example, repairing a press tool in the automotive industry requires a laser with a power output exceeding 1 kW. The welder repairs the workpiece by holding the laser in one hand and a feed wire in the other, transferring the melted material from the wire to the area requiring repair. Due to the high power of the laser, this is particularly dangerous, even life-threatening, for the welder.

[0005] A method of the above-mentioned type is known from WO 2014 14 49 46 A2 and DE 196 14 418 C1. A further method is known from DE 11 2011 103 499 T5 in which damage to be repaired in an inaccessible location is recorded using an imaging technique and the image is then analyzed to determine a repair plan.

[0006] Furthermore, EP 3 209 451 B1 should be mentioned, where a portable metalworking robot system with communication circuit and control system for the virtual control of a metalworking process is disclosed. Task

[0007] Due to the risk to the life of the user of a laser processing device, it is important that the present invention reduces or completely avoids this significant risk. Solution to the task

[0008] The problem is solved by a method for machining a workpiece with the features of claim 1. The problem is further solved by a device for carrying out the method with the features of claim 8.

[0009] The method according to the invention is intended in principle to be used for processing workpieces, but in particular for carrying out surface repairs with a laser. This area to be processed is then referred to as a defect.

[0010] Firstly, the position of the tool relative to the workpiece is thus determined by the position of the control element. However, the major advantage of the present invention lies in the fact that both the pressure and the position are determined by the control element, so that the welder can perform his work outside the area of ​​the tool.

[0011] As an example, let's consider a case from the manufacturing of an automotive part. For instance, a trunk lid is to be manufactured in a press. The manufacturing process takes place between two press jaws. During production, it's possible that an object, such as a screw, might unintentionally get caught between these two jaws. This screw would then be pressed into one of the jaws, leaving a defect.

[0012] In a work step according to the present invention, an image is taken of the area to be processed or the defect in the workpiece. This can be a normal image or, as in the preferred embodiment, a 3D image.

[0013] This image appears on an imaging device, such as a screen, iPad, or even 3D glasses. The screen, iPad, or 3D glasses are freely movable and do not need to be in the same room as the workpiece being processed. This offers the significant advantage that the user does not need to be in the same room as the dangerous laser.

[0014] For position detection, in a preferred embodiment, lines are affixed to the workpiece parallel to the weld paths (defects in the workpiece). Image recognition will likely not be able to detect the exact position on the workpiece (reflections in the metal, no clear edges). Therefore, the affixed lines serve as an aid, allowing the camera to establish a relationship between the workpiece and the defect. The welding robot then orients itself using these affixed lines, which are removed after processing. The affixed lines can also be replaced by other objects, such as fiducials (crosses, circles, etc.).

[0015] This procedure is necessary, among other things, when the welding robot is not fixed in place and is therefore moved across the workpiece. In this case, the robot's zero position relative to the workpiece is unknown, which is determined by the applied lines.

[0016] In a further step, the image of the "welder" is traced with the control element. Since this takes place on the screen, the user can clearly see how and where to move the welding tool. This allows the welding work to be carried out very precisely.

[0017] Furthermore, in the preferred embodiment, the control element is a pen that includes a sensor for its position and a pressure sensor. Holding a pen in the hand is the most natural thing in the world and is learned by humans from an early age; the preferred embodiment takes advantage of this, because the ease of handling a pen allows the weld bead to be followed very precisely.

[0018] The tool, in this case a welding robot, is positioned on the damaged workpiece, preferably near the defect. The control element, or in the preferred embodiment, the pen, then traces the image. By changing the pen's position and the pressure exerted on or by it, the type and / or intensity of the welding robot's activity are determined. That is, the pen's position and pressure data are transmitted to the welding robot's control system and translated into the position of the welding nozzle. The applied pressure, in particular, determines the wire feed rate, especially the speed, by which material is introduced into the defect. In other words, the welder uses the pen to simulate the task they would normally perform manually with the corresponding welding robot.

[0019] The control unit and the welding robot can be, but do not have to be, in the same room. All devices are preferably connected wirelessly. This allows for very precise work and, above all, ensures user safety.

[0020] It should also be noted that after the aforementioned steps, another image of the defect can be taken to verify that it has been repaired. Any raised areas can be ground down and imperfections corrected. This means that the welded defect or weld seam is scanned again with the camera after creation or modification to measure the weld quality and position. This is then done manually on the tablet, either with or without comparison to the overlay of the CAD data (design model).

[0021] It is also conceivable that the pressure / force is determined not by the sensor in or on the pen, but by the user's finger. The force applied to the finger is also measured by a sensor and then transmitted to the pen.

[0022] During the entire process, it is of course possible to intervene in the process and correct the welding robot's activity if errors are detected.

[0023] In another possible embodiment, the use of 3D glasses is also possible. This allows the user to monitor the welding process while the defect is being repaired.

[0024] The case described above from the automotive industry is just one example. Countless other situations are conceivable in which the inventive method could be applied. All such situations are intended to be covered by the present invention.

[0025] The invention also includes a device for carrying out the method. Character description

[0026] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawing; the single figure of this drawing shows a schematic representation of a device according to the invention for machining a workpiece. This figure represents the schematic diagram D of the process sequence according to the invention with the work steps P1 and P2.

[0027] In the preferred embodiment, the first step P1 involves a press tool 1, for example, from the automotive industry. This tool has press jaws 2.1 and 2.2. If an object 3, for example a screw, falls between the press jaws 2.1 and 2.2 and the press jaws 2.1 and 2.2 close, at least one surface 4.1 and / or 4.2 of at least one press jaw 2.1 and / or 2.2 is significantly damaged, creating a defect 5.

[0028] To repair this defect 5, in a second step P2 a camera 6, preferably a 3D camera, is moved towards the defect 5. This captures a 3D image 7 of the damaged area.

[0029] For position detection, in a preferred embodiment, lines are affixed to the workpiece parallel to the paths to be welded (defects in the workpiece). The affixed lines can also be replaced by other objects such as fiducials (crosses, circles, etc.).

[0030] The resulting image 7, or the generated data, is then sent in a third step P3 to an image display device 8, in a preferred embodiment, for example, an iPad, touchpad, or screen. The image data 7 is opened and processed in a special program. This predefines the welding paths for the welding robot. These paths are then subsequently followed automatically by the welding robot.

[0031] The device 8 is associated with a control element 10, for example, a pen, which is connected to a welding robot 9. This control element, or in the preferred embodiment, a pen 10, includes a sensor for its position and a pressure sensor. The defect 5 is then traced with this pen 10, which is moved in the same way as a welding nozzle of the welding robot 9 would move in space. A change in the pressure applied to the pen 10, or with the pen 10 to the defect 5, simulates the wire feed of the welding wire. The user essentially welds the defect 5 closed with the pen 10. This data from the pen 10 is transmitted to the welding robot 9 or its controller, whose welding nozzle and wire feed are activated accordingly, thereby welding the defect 5 closed.

[0032] The captured image can also be compared with overlaid design data to constructively address the defect, e.g., a hole in the mold, and to specify the travel paths for the laser to fill (weld) the hole.

[0033] The system compares the image captured by the camera with the design data. The user interactively fills holes or draws the weld paths using the pen; this information is then transferred to the welding robot and processed. The pressure applied to the pen again determines the feed rate of the welding wire, thus defining the amount of material required for the weld or filling of the holes.

[0034] The pen 10 can also be used to draw entire welding paths, register them in the computer, and transfer them to the welding robot 9. The welding robot 9 then follows them.

[0035] The welding robot 9 can, but does not have to, be in the same room as the control element 10. Therefore, to carry out dangerous welding work, it is possible and also advisable to control the welding robot 9 from an adjacent room.

[0036] Another image can then be taken to see if defect 5 has been eliminated. Any raised areas can be sanded down and imperfections corrected.

[0037] It is also conceivable that the pressure / force is determined not by the sensor, but by the user's finger. The force is also picked up from the finger by a sensor and applied to the pen 10.

[0038] During the entire process, if errors are detected, the process can of course be intervened in and the activity of robot 9 corrected.

[0039] In another possible embodiment, the use of 3D glasses is also possible. This allows the user to monitor the welding process while the defect 5 is being repaired. Reference symbol list 1 pressing tool 2 pressing jaws 3. Item 4 Surface 5 defects 6 cameras 7 image data 8 Picture Setup 9 welding robots 10 pens

Claims

[1] Method for processing a workpiece (2) using a tool (9) which is a welding robot with a laser, for repairing a surface (4) of the workpiece (2) with the laser by welding with welding wire, wherein the welding wire is fed to the tool (9) with a wire feeder, the method comprising the following steps: - Taking a picture (7) of the area to be processed or the defect (5) of the workpiece (2) with a camera (6), - Display of the image (7) on an imaging element (8), which is a touchpad or touchscreen; - Marking the area to be worked on or the defect (5) by lines affixed to the workpiece (2); - Controlling the tool (9) with a control element (10), wherein the control element (10) is a pen containing a position sensor and a pressure sensor, - wherein a position of the tool (9) relative to the workpiece (2) is controlled via a position of the control element (10) relative to the imaging element (8), - and wherein a pressure exerted by the control element (10) on the imaging element (8) controls the wire feed to the tool (9), - wherein the control element (10) is connected to a control of the tool (9), - wherein the controller is configured to receive data from the control element (10) from the position sensor and the pressure sensor, which are executed by the controller to control the tool (9). [2] Method according to claim 1, characterized by , that the position of the tool (9) relative to the workpiece (2) to be machined is determined by the position of the control element (10). [3] Method according to claim 1, characterized by , that the image (7) is scanned by the control element (10). [4] Method Claim 1, characterized by, that the image (7) appears on a screen or 3D glasses. [5] The method of claim 1, further comprising the following steps: - the camera (6) is used to capture the image (7) of the area to be processed or of the defect (5) in the workpiece (2); - the image (7) is transferred from the camera (6) to the imaging element (8); - the image (7) is visibly displayed on or in the image-forming element (8); - the tool (9) is positioned with regard to the area to be machined or the defect (5) of the workpiece (2); - the image (7) is moved by the control element (10); - by changing the position of the control element (10) and the pressure exerted on or by it, an activity and / or an intensity of the activity of the tool (9) is determined. [6] Method according to at least one of the preceding claims, characterized by, that a welded defect or weld seam is scanned again with the camera (6) after creation and processing. [7] Device for processing a workpiece (2) by means of a tool (9) which is a welding robot with a laser, for repairing a surface (4) of the workpiece (2) with the laser by welding with welding wire, wherein the welding wire is fed to the tool (9) with a wire feeder, with a camera (6) to take a picture (7) of a part of the workpiece to be processed (2), wherein the image (7) is displayed on an imaging element (8), wherein the imaging element (8) is a touchpad or a touchscreen, wherein a control element (10) is a pen incorporating a position sensor and a pressure sensor, wherein a position of the tool (9) relative to the workpiece (2) is controlled via a position of the control element (10) relative to the imaging element (8). and wherein a pressure exerted by the control element (10) on the imaging element (8) controls the wire feed to the tool (9), wherein the control element (10) is connected to a control of the tool (9), and wherein the controller is configured to receive data from the control element (10) from the position sensor and the pressure sensor, which are executed by the controller to control the tool (9).

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