Method and device for component machining
By maintaining feed motion during image acquisition and compensating for image capture time with accelerated machining, the method and device enhance image capture efficiency and quality assessment in scanner-based processes.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- MERCEDES BENZ GROUP AG
- Filing Date
- 2025-05-09
- Publication Date
- 2026-06-11
AI Technical Summary
In scanner-based processes, capturing images of sufficient sharpness during machining processes is challenging due to motion blur caused by rapid pendulum movements of the deflection unit, leading to inefficiencies and reduced quality assessments.
The method and device enable continuous feed motion during image acquisition by rotating the deflection unit to maintain the camera's field of view on the processed area, followed by accelerating the machining process to compensate for the image capture time, allowing for dynamic and efficient image capture without additional processing time.
This approach allows for more images to be captured during processing without time loss, enabling improved and reliable quality assessments with adaptable image capture parameters.
Smart Images
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Abstract
Description
[0001] The invention relates to a method for machining components.
[0002] The invention further relates to a device for component machining according to the preamble of claim 7.
[0003] From DE 10 2016 008 996 A1, a machine learning device is known which learns to determine arc welding conditions. The learning device comprises - a state observation unit that observes a state variable, comprising a physical quantity relating to arc welding during or after arc welding, and the arc welding conditions, and - a learning unit that learns about a change in the physical quantity observed by the state observation unit and the arc welding conditions in relation to each other.
[0004] Arc welding conditions include a welding process, welding current, welding voltage, welding wire feed rate, welding speed, a welding waveform adjustment, welding wire elongation, left / right welding torch angle, welding torch aiming angle, torch aiming position, shielding gas flow rate, weaving weld welding condition, arc sensor condition, and weld position offset in a pass weld. Physical quantities related to arc welding include image data of a welded part acquired by an image acquisition unit, as well as the external appearance of a weld bead, its thickness, and the amount of metal spatter produced.
[0005] Furthermore, DE 10 2016 107 581 B3 discloses a welding method for joining workpieces at an overlap joint with a weld seam consisting of a plurality of individual weld seam sections using a remote laser welding device. The remote laser welding device comprises a processing laser for generating a laser beam, a feed device for generating a feed movement in a predetermined weld seam direction, and a scanner optic with an active deflection unit. The laser beam performs an anharmonic oscillating pendulum motion superimposed on the feed movement, with an oscillation frequency of 2 Hz to 20 Hz, whereby a laser spot generated by the laser beam on a workpiece surface plane of the workpieces to be joined oscillates back and forth with an oscillation amplitude in the range of 1 mm to 20 mm.The power input of the laser beam into the workpieces is periodically varied between a maximum and a minimum value, with the maximum power input causing the workpieces to melt at the overlap joint, while the minimum power input is below the level required for melting. The power input is coupled to the oscillating motion of the laser beam, with one oscillation period of the anharmonic oscillation being equal to the power input period or an integer multiple thereof. Linear, parallel weld sections are formed with identical geometric dimensions, the projection of which onto the workpiece surface plane perpendicular to a weld seam results in a continuous line.For process monitoring, a measuring light is emitted, which spreads from the workpiece surface plane via the active deflection unit, a focusing unit, through a semi-transparent, passive deflection unit and a camera focusing unit to a camera.
[0006] DE 10 2019 210 618 A1 discloses the following: A system and method can be used to monitor and / or control a wobble welding process using coherent inline imaging (ICI). While at least one process beam is moved according to a wobble pattern at a weld point on a workpiece, an ICI system moves at least one imaging beam, at least partially independently of the process beam, to one or more measurement locations in the wobble pattern and acquires ICI measurements (e.g., depth measurements) at these locations. The ICI measurement(s) can be used, for example, to assess vapor capillary and / or weld pool properties during the welding process.The systems and methods described herein can also be used in other material processing applications where a laser or other energy beam is guided in a wobble or tumbling motion during processing, including, but not limited to, additive manufacturing, marking and material removal.
[0007] The invention is based on the objective of providing a novel method and a novel device for component machining.
[0008] The problem is solved according to the invention by a method which has the features specified in claim 1 and by a device which has the features specified in claim 5.
[0009] Advantageous embodiments of the invention are the subject of the dependent claims.
[0010] The inventive method for component machining provides that during a normal machining process - a processing beam designed for processing a component is emitted onto a reflective surface of a deflection unit and directed onto a surface of the component by means of the deflection unit, - a feed movement of the deflection unit or the component in a feed direction is generated, - a pendulum motion of the deflection unit is generated around a pendulum axis which lies in a plane spanned from the reflection surface by a longitudinal axis running in the feed direction and a vertical axis running in the direction of the component, during an image acquisition process following the normal processing process, while maintaining the feed movement - the emission of the processing beam and the pendulum movement of the deflection unit are stopped, - the deflection unit is rotated from a starting position around a rotation axis perpendicular to the longitudinal and vertical axes in a first direction of rotation into a target position, so that a detection area of a camera, whose optical axis is directed towards the reflective surface of the deflection unit, is directed towards an area of the surface of the component that has already been processed by means of the processing beam, and - at least one image of the processed area is captured by the camera during an accelerated processing process following the image capture process, while maintaining the feed movement - the emission of the processing beam is activated, - simultaneously the pendulum movement of the deflection unit is activated and - simultaneously, the deflection unit is rotated from the target position in a second direction of rotation opposite to the first direction of rotation at a speed around the axis of rotation such that a resulting speed of an impact point of the processing jet on the surface of the component in the feed direction is greater than a speed of the feed movement, and Once the starting position is reached, the normal processing process is activated.
[0011] The device for component machining features: - an emitter which is designed to emit a processing beam designed for processing a component, - a camera, - a deflection unit with a reflective surface, which is designed to deflect the processing beam and an optical axis of the camera onto a surface of the component, - a rotary drive unit coupled to the deflection unit, which is designed to generate rotary movements of the deflection unit, and - a feed drive unit coupled to the component or to the emitter and deflection unit and the camera, which is designed to generate a feed movement of the component or the emitter and the deflection unit and the camera in a feed direction.
[0012] According to the invention, the device further comprises a control device which is configured to control the emitter, the camera, the deflection unit, the rotary drive unit and the feed drive unit for carrying out the aforementioned method.
[0013] In a path process with rapid pendulum motion, i.e., with movement in the feed direction and simultaneously superimposed pendulum motion of the deflection unit perpendicular to the feed direction, for example in so-called scanner-based processes, images of sufficient sharpness cannot be captured during the machining process if the capturing camera uses the deflection unit to position its capture area on the surface of the component, because motion blur occurs as a result of the rapid pendulum movements.
[0014] In the present method and using the present device, unlike methods and devices known from the prior art, the feed motion is not interrupted during image acquisition. Instead, the deflection unit and the camera continue to move with the feed motion unchanged, and the deflection unit is rotated in such a way that the camera's field of view is directed towards this area via the deflection unit. After the image has been acquired, which is used, for example, to determine the quality of the machining of the component, the machining of the component is accelerated in the machining process by increasing the rotational speed of the deflection unit relative to the speed of the feed motion, until the time required without machining due to the image acquisition process has been "made up for."This results in the particularly advantageous fact that no additional processing time is required to capture at least one image. Furthermore, the method and the device enable a larger number of images to be captured during component processing without any time loss, compared to previously known solutions, thus allowing for improved and more reliable quality assessments. Moreover, the method and the device allow for dynamic or variable image capture with regard to the number of images captured, as well as the position, time, and duration of image capture. This enables image capture for quality verification to be adapted to the processing process.
[0015] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.
[0016] This shows: Fig. 1 schematically a device for component machining and a component, Fig. 2 schematically a top view of a component at a first point in time, Fig. 3. Schematic top view of the component according to Fig. 2 at a second time and Fig. 4 schematically a top view of the component according to Fig. 2 at a third point in time.
[0017] Corresponding parts are marked with the same reference symbols in all figures.
[0018] Fig. Figure 1 shows a schematic representation of a possible embodiment of a device 100 for component machining and a component 200.
[0019] The device 100 comprises an emitter 101, a camera 102, a deflection unit 103 with a reflective surface 104, a rotary drive unit 105 coupled to the deflection unit 103, a feed drive unit 106 coupled to the emitter 101, the deflection unit 103 and the camera 102, and a control device 107 coupled to the emitter 101, the camera 102, the deflection unit 103, the rotary drive unit 105 and the feed drive unit 106 via data transmission.
[0020] For example, the device 100 is designed as a laser welding device or as a laser surface processing device, wherein the emitter 101 and the deflection unit 103 form a laser scanner.
[0021] The feed drive unit 106 is configured to generate a feed movement V of the deflection unit 103, the emitter 101, and the camera 102 in a feed direction VR. The feed drive unit 106 is, for example, formed by a robot that moves the deflection unit 103, the emitter 101, and the camera 102 in the feed direction VR. Alternatively, the feed drive unit 106 is configured to move the component 200 relative to the deflection unit 103, the emitter 101, and the camera 102 in a feed direction VR.
[0022] The emitter 101 is designed to emit a processing beam 108, for example a laser beam, for processing the component 200 and emits this onto the reflective surface 104 of the deflection unit 103. By means of the deflection unit 103, the processing beam 108 is directed onto a surface 201 of the component 200.
[0023] The camera 102 is designed to detect the surface 201 of the component 200. For this purpose, an optical axis of the camera 102 is directed towards the reflective surface 104 of the deflection unit 103, so that a detection area 109 of the camera 102 is directed onto the surface 201 of the component 200 by means of the deflection unit 103.
[0024] The rotary drive unit 105 is configured to generate a pendulum movement PB of the deflection unit 103 around a zero position about a pendulum axis P. The pendulum axis P lies in a plane that is spanned from the reflective surface 104 by a longitudinal axis x extending in the feed direction VR and a vertical axis z extending in the direction of the component 200.
[0025] The rotary drive unit 105 is further configured to rotate the deflection unit 103 about a rotation axis D perpendicular to the longitudinal axis x and the vertical axis z and in the direction of a transverse axis y in a first direction of rotation R1 and a second direction of rotation R2 opposite to this.
[0026] The control device 107 is designed to control the emitter 101, the camera 102, the deflection unit 103, the rotary drive unit 105 and the feed drive unit 106.
[0027] Based on the following Fig. 2, Fig. 3 to Fig. Section 4 describes a possible embodiment of a method for machining component 200, which is carried out using the device 100.
[0028] In Fig. Figure 2 shows a top view of component 200 and a scan field S of a scanner, for example a laser scanner, formed by the emitter 101 and the deflection unit 103, at a first time t1. Using the device 100, for example, a weld 300 is created with another component located below component 200 (not shown in detail). Alternatively, using the device 100, a surface structure is created on component 200, the shape of which can correspond to the weld 300 shown. The process sequence described below is illustrated using the example of creating the weld 300. The process sequence for creating the surface structure is analogous.
[0029] For this purpose, during a normal machining process NB carried out before the first time t1, the feed drive unit 106 is controlled by means of the control device 107, so that it generates the feed movement V of the deflection unit 103, the emitter 101 and the camera 102 in the feed direction VR.
[0030] At the same time, the emitter 101 is controlled by means of the control device 107, so that it emits the processing beam 108, for example designed as a laser beam, onto the deflection unit 103.
[0031] Furthermore, the control device 107 controls the rotary drive unit 105, causing it to generate the oscillating movement PB of the deflection unit 103 about the oscillation axis P. This causes the processing beam 108 to be emitted onto the surface 201 of the component 200 in such a way that its point of impact on the surface 201 of the component 200 oscillates at least substantially in the direction of the transverse axis y, creating a weld joint 300 that extends at least substantially transversely around a path B formed on the surface 201 and directed in the feed direction VR. The weld joint 300 is formed from several sections 300.1 to 300.n that extend at least substantially transversely to the path B. These sections 300.1 to 300.n can run parallel to each other, at least in sections. This can be achieved by pulsed emission of the processing beam 108. In particular, sections 300.1 to 300.n is generated in such a way that they overlap in the direction of the longitudinal axis x and thus form a continuous weld joint 300 in the longitudinal direction x without unprocessed gaps.
[0032] To verify the quality of the weld 300 produced, at least one image of an area 202 of the surface 201 of the component 200 that has already been processed by the processing beam 108 is captured and evaluated using the camera 102. The area 202 may have different shapes than those shown.
[0033] To capture at least one image with sufficient sharpness, at the first time t1, during an image acquisition process BE following the normal processing process NB, the emitter 101 and the rotary drive unit 105 are controlled by the control device 107 while maintaining the feed movement V, such that the emission of the processing beam 108 and the pendulum movement PB of the deflection unit 103 are stopped. In particular, the deflection unit 103 is moved to the zero position or pivoted position with respect to the pendulum axis P, so that an optical axis of the camera 102 is directed onto the path B on the surface 201 of the component 200.
[0034] Furthermore, the control device 107 controls the rotary drive unit 105 in such a way that the deflection unit 103, starting from a position in Fig. The starting position shown in Figure 1 is rotated around the axis of rotation D in the first direction of rotation R1 to a target position, so that the detection area 109 of the camera 102 is directed towards the area 202 of the surface 201 of the component 200 that has already been processed by the processing beam 108. Thus, the detection area 109 of the camera 102 is moved along the surface 201 of the component 200 in a direction opposite to the feed direction VR, while the feed movement V continues. In one possible embodiment, the deflection unit 103 remains in the target position after reaching it, regardless of the feed movement V, while at least one image is captured by the camera 102.In a further possible embodiment, once the target position is reached, the deflection unit 103 is rotated in the second direction of rotation R2 such that the feed movement V is compensated and the detection area 109 of the camera 102 always covers the same area 202 on the surface 201 of the component 200. This means that during image acquisition, the image position relative to the component 200 remains unchanged. It is also possible to acquire multiple images of multiple areas 202 of the surface 201 of the component 200.
[0035] Fig. Figure 3 shows a top view of component 200 and the scan field S according to Fig. 2 at the end of the image acquisition process BE at a second time t2, at which the acquisition of at least one image is completed.
[0036] Due to the feed movement V continuing to be performed during the image acquisition process BE with emitter 101 deactivated, no weld joint 300 is created on part of the component 200 between time t1 and time t2.
[0037] To create the weld joint 300 in this part and to compensate for a time period between time t1 and time t2, i.e. to make up for the time period used to capture at least one image, an accelerated machining process BB is carried out from time t2 onwards while maintaining the feed movement V.
[0038] The control device 107 controls the emitter 101 such that the emission of the processing beam 108 is activated. Simultaneously, the control device 107 activates the pendulum movement PB of the deflection unit 103, and the deflection unit 103 is rotated back to the starting position from the target position or a position subsequently assumed thereafter in the second direction of rotation R2, opposite to the first direction of rotation R1. This rotation occurs at a speed such that the resulting velocity of an impact point of the processing beam 108 on the surface 201 of the component 200 in the feed direction VR is greater than the speed of the feed movement V.
[0039] This accelerated processing process BB continues until the deflection unit 103 has returned to its starting position. Once this is the case, the normal processing process NB is executed again.
[0040] This means that at time t2, immediately after the acquisition of at least one image, the processing of component 200 continues in such a way that the optical regression performed by the deflection unit 103 is "compensated for" by at least one specific process parameter, in particular the speed of rotation towards the starting position, which causes the resulting speed of the impact point of the processing beam 108 to be higher than the speed of the feed movement V. In particular, the degree of overlap between the individual sections 300.1 to 300.n is reduced. Since this only occurs for the short period required to compensate for the time interval between the first and second time points t1, t2, the risk of defects in the resulting weld joint 300 can be minimized.
[0041] In Fig. Figure 4 shows a top view of component 200 and the scan field S according to Fig.Figure 2 shows the end of the accelerated machining process BB at a third time point t3. Between the second time point t2 and the third time point t3, the weld joint 300 is produced using the accelerated machining process BB. From the third time point t3 onwards, the weld joint 300 is produced again using the normal machining process NB.
[0042] In an alternative embodiment, the deflection unit 103 has at least two deflection mirrors, wherein a first deflection mirror is pivotable about a rotation axis extending in the direction of the transverse axis y, and a second deflection mirror is pivotable about the pendulum axis P. During the process described above, the processing beam 108 is moved in the direction of the longitudinal axis x by means of the first deflection mirror and in the direction of the transverse axis y by means of the second deflection mirror in the pendulum motion PB. In particular, a combined movement of the two deflection mirrors is carried out such that, without a feed motion V, the point of impact of the processing beam 108 on the surface 201 of the component 200 would sweep out a closed curve having the shape of an hourglass or a "horizontal figure eight". With a constant activated feed motion V, sections 300.1 to 300.n are thus generated parallel to each other and extending in the direction of the transverse axis y.
Claims
Method for component machining, wherein during a normal machining process (NB) - a machining beam (108) designed for machining a component (200) is emitted onto a reflective surface (104) of a deflection unit (103) and is directed by means of the deflection unit (103) onto a surface (201) of the component (200), - a feed movement (V) of the deflection unit (103) or of the component (200) is generated in a feed direction (VR), and - a pendulum movement (PB) of the deflection unit (103) is generated about a pendulum axis (P), which lies in a plane that is spanned from the reflective surface (104) by a longitudinal axis (x) extending in the feed direction (VR) and a vertical axis (z) extending in the direction of the component (200).During an image acquisition process (BE) following the normal processing process (NB) while maintaining the feed movement (V), the emission of the processing beam (108) and the pendulum movement (PB) of the deflection unit (103) are stopped, the deflection unit (103) is rotated from a starting position about a rotation axis (D) perpendicular to the longitudinal axis (x) and the vertical axis (z) in a first rotation direction (R1) to a target position, so that a detection area (109) of a camera (102), whose optical axis is directed towards the reflective surface (104) of the deflection unit (103), is directed towards an area (202) of the surface (201) of the component (200) that has already been processed by means of the processing beam (108), and at least one image of the processed area (202) is captured by means of the camera (102).During an accelerated machining process (BB) following the image acquisition process (BE), while maintaining the feed motion (V), the emission of the machining beam (108) is activated, the pendulum motion (PB) of the deflection unit (103) is activated, and the deflection unit (103) is simultaneously rotated from the target position in a second direction of rotation (R2) opposite to the first direction of rotation (R1) at a speed around the axis of rotation (D) such that a resulting speed of an impact point of the machining beam (108) on the surface (201) of the component (200) in the feed direction (VR) is greater than a speed of the feed motion (V), and after reaching the start position, the normal machining process (NB) is activated. Method according to claim 1, wherein a laser beam is used as the processing beam (108). Method according to claim 1 or 2, wherein a weld connection (300) is created between the component (200) and at least one further component by means of the processing beam (108). Method according to one of the preceding claims, wherein the image acquisition process (BE) is performed multiple times between a single normal processing process (NB) and a single accelerated processing process (BB). Device (100) for component processing, comprising: - an emitter (101) configured to emit a processing beam (108) designed for processing a component (200); - a camera (102); - a deflection unit (103) with a reflective surface (104) configured to deflect the processing beam (108) and an optical axis of the camera (102) onto a surface (201) of the component (200); - a rotary drive unit (105) coupled to the deflection unit (103) configured to generate rotary movements of the deflection unit (103); - a feed drive unit (106) coupled to the component (200) or to the emitter (101) of the deflection unit (103) and the camera (102), configured to generate a feed movement (V) of the component (200). (V) of the emitter (101) and the deflection unit (103) and the camera (102) to generate a feed direction (VR), characterized by a control device (107),which is configured to control the emitter (101), the camera (102), the deflection unit (103), the rotary drive unit (105) and the feed drive unit (106) for the execution of a method according to one of the preceding claims.