Robot laser ablation system and method for curved-surface parts

Abstract

The invention discloses a robot laser ablation system and method for curved-surface parts, and belongs to the technical field of laser machining. The robot laser ablation system comprises a six-degree-of-freedom mechanical arm, a laser machining head, a connecting plate, a console, a tool adjusting platform and a laser generator; according to the method, mechanical arm laser ablation device building, transformation matrix obtaining and curved surface part laser ablation are conducted, efficient laser ablation machining can be conducted on curved surface parts, and compared with traditional cutting or grinding, the machining effect of rapidly removing large allowance is achieved; as the laser processing does not need to directly contact with the parts, the parts are simple to mount and position; for machining with the high precision requirement, the method can serve as a rough machining scheme, a CAM program can be automatically converted into a mechanical arm machining file by means of numerical control program conversion software, and the mechanical arm machining instruction compiling difficulty is reduced.

Description

Technical Field

[0001] This invention belongs to the field of laser processing technology, specifically relating to a robotic laser ablation system and method for curved parts. Background Technology

[0002] Laser ablation can significantly improve material removal efficiency when machining hard and brittle materials. However, due to the complex structure of curved parts and the higher requirements for machining freedom, the machining process is more complex than that for planar parts. Common laser surface ablation methods typically use polygonal facets to obtain normal vectors and then perpendicularize the laser spot to the surface of the curved part. The accuracy of this method depends on the size of the facets, but the computational complexity, especially for complex curved surfaces, makes the computational time cost unacceptable for batch processing. Furthermore, facets need to be re-extracted for different curved surfaces, resulting in poor machining trajectory flexibility. This proposal suggests a robotic laser ablation method for curved parts. A laser is mounted at the end effector of a robotic arm. Utilizing the high degree of freedom of the robot, the laser spot moves along a specific trajectory during the machining of curved parts, ensuring that the laser spot focus is on the surface of the curved part, thereby achieving efficient laser ablation machining of curved parts.

[0003] Chinese patent CN108555464A discloses a method and system for dynamic focusing laser processing of large and complex curved surfaces. It uses a segmentation-blocking-layering approach to decompose complex curved surfaces. Although it can achieve dynamic focusing of complex curved surfaces, the device has poor flexibility and low efficiency when processing thick curved parts.

[0004] Chinese patent CN208195762U discloses a processing device for laser heating-assisted milling of curved surfaces. Although the device can use a laser to locally heat the workpiece, thereby improving the workpiece's machinability, it cannot directly remove material and lacks a calculation method between the laser head position parameters and the milling cutter position, making it impossible to accurately ensure that the laser spot is always on the workpiece surface. Summary of the Invention

[0005] To address the problems in existing technologies, a robotic laser ablation system and method for curved parts are provided. This includes the construction of a robotic arm laser ablation device, acquisition of the transformation matrix, and the laser ablation method for curved parts. This enables efficient laser ablation processing of curved parts, offering a faster removal of large amounts of material compared to traditional cutting or grinding. Since laser processing does not require direct contact with the part, part installation and positioning are relatively simple. For high-precision machining, this method can be used as a roughing solution. With the help of CNC program conversion software, the CAM program can be automatically converted into robotic arm machining files, reducing the difficulty of programming robotic arm machining instructions.

[0006] This invention is achieved through the following technical solution: A robotic laser ablation system for curved parts includes a six-degree-of-freedom robotic arm, a laser processing head, a connecting plate, a control console, a tooling adjustment platform, and a laser generator. The laser generator is connected to the laser processing head, and the control console is connected to both the six-degree-of-freedom robotic arm and the laser generator. The six-degree-of-freedom robotic arm moves along a specific trajectory during processing. The laser processing head is mounted on the end effector of the six-degree-of-freedom robotic arm via the connecting plate. The control console provides automated control of the processing process. The tooling adjustment platform is used to adjust the position and orientation of the part to be processed and its tooling.

[0007] Preferably, the console includes a robotic arm control module and a laser control module; the robotic arm control module is used to call and execute different robotic arm control programs to ensure that the tool coordinate system moves along a specific trajectory at a predetermined feed rate. The machining program is generated post-processed by a program written in CAM software. In the robotic arm control program, the laser processing head is switched on and off by instructions; the laser control module is used to set and adjust the relevant parameters of laser ablation.

[0008] Preferably, it also includes a cooling unit for reducing the temperature generated by the laser processing head during use.

[0009] A robotic laser ablation method for curved parts includes the following steps: Step 1: Determine laser ablation parameters; Step 2: CNC program development; Step 3: CNC program conversion; Step 4: Verify the accuracy of the trajectory; Step 5: Laser processing.

[0010] Preferably, in step one, the laser ablation parameters are determined through an ablation test; the ablation parameters include the robotic arm feed speed, the shape and size of the ablation area, the laser power, the spot scanning speed, and the spot scanning line interval.

[0011] Preferably, the ablation test process is as follows: The starting point, ending point, and feed speed of the robotic arm are manually set in the robotic arm control module of the control console; the shape and size of the ablation area, laser power, spot scanning speed, and spot scanning line interval are set in the laser control module; after starting the robotic arm control module, the robotic arm moves along a straight line from the starting point to the ending point at the given feed speed, and the laser processing head is started after the movement begins and turned off at the end; without changing the starting and ending points of the robotic arm movement, the ablation parameters are repeatedly adjusted, and the ablation depth, ablation uniformity, and ablation dust accumulation of the hard and brittle material after ablation are observed. Different ablation parameters are selected according to processing requirements.

[0012] Preferably, in step two: a tooling model and a part model are established in CAM software, and a workpiece coordinate system is established on the tooling model. The theoretical values ​​of the distances between the workpiece coordinate system and the edge of the tooling are recorded. 、 ; Compile toolpath programs in the workpiece coordinate system: When the toolpath needs to be processed in layers, the distance between layers should be consistent with the ablation depth in step one to ensure that the laser focus position is always on the surface of the area to be processed; After the program is completed, export the toolpath file in APT format.

[0013] Preferably, the transformation relationship between the workpiece coordinate system and the base coordinate system is as follows: Assuming that there is only translation transformation and no rotation transformation between the end effector coordinate system and the tool coordinate system, if the end effector coordinate system... Translation of axes respectively After obtaining the tool coordinate system, the transformation matrix is ​​obtained: ; Since a six-DOF robotic arm is simplified to a six-DOF link, the base is defined as link 0, and so on, with the end effector as link 6. The transformation matrix from the base coordinate system to the end effector coordinate system is obtained using the improved DH method: ; in: ; The parameters in the matrix have the following meanings: a) around Axis rotation Angle, make shaft and The axes are in the same plane; b) around Axis translation ,make shaft and The axes are at the same height; c) around Axis rotation Angle, make shaft and The axes are on the same straight line; d) along Axis translation distance , making the connecting rod The origin of the coordinate system and the connecting rod The origins of their coordinate systems coincide; Therefore, the transformation matrix from the base coordinate system to the tool coordinate system Since the tool coordinate system changes during the machining process, it is assumed that there exists Given n trajectory points, each corresponding to the current tool coordinate system, then the nth trajectory point... The transformation matrix of each tool coordinate system is The inverse kinematics algorithm of the robotic arm is used to solve the joint position of the robotic arm in the current posture.

[0014] Preferably, the transformation relationship between the workpiece coordinate system and the base coordinate system is as follows: (Workpiece coordinate system...) The plane is usually flush with the upper surface of the tooling, and The axis points vertically upwards; this is to obtain the translation transformation matrix. The workpiece coordinate system needs to be set first. Adjust the plane to be level and adjust... Axis and base coordinate system The axes remain parallel.

[0015] Preferably, the adjustment method is as follows: When placing the tooling, adjust the long side relative to the base coordinate system. The axes are roughly parallel; use a magnetic dial indicator holder to mount the dial indicator onto the connecting plate, adjust the dial indicator measuring head to the tooling plane, and manually operate the robotic arm along... shaft and Move the axis and observe the change in the dial indicator. Assume the dial indicator moves along the axis. , The maximum and minimum values ​​during the axis motion process are respectively , , , Based on the difference in the dial indicator readings, adjust the base screws of the tooling adjustment platform until the desired result is achieved. ,and At that time, it was assumed that the tooling platform had been leveled and the workpiece coordinate system was... Adjust the plane to be level, and record the plane's position at the same time. Value ;in, The tolerances of the parts to be processed are determined comprehensively; similarly, the dial indicator measuring head is adjusted to the long side surface of the tooling, and the robotic arm is manually operated along... The axis moves without causing rotation of the end effector's coordinate axis. At that time, the workpiece coordinate system can be considered as , Axis and base coordinate system , Keep the axes parallel; next, align the dial indicator measuring head with the laser focus position, and operate the robotic arm to bring the dial indicator close to the fixture from the long and short sides respectively, without rotating the end effector coordinate axis during the process. When the dial data changes abruptly from zero, it can be considered that the laser focus position has contacted the fixture. Record the position of the robotic arm when contacting the long and short sides respectively. and ; Theoretically, the workpiece coordinate system The distance between the shaft and the long side of the tooling is , The distance between the shaft and the long side of the tooling is Since the values ​​recorded by the robotic arm are the coordinates of the center of the end effector flange in the world coordinate system, the coordinates of the workpiece coordinate system origin in the base coordinate system can be obtained through theoretical calculations. The translation transformation matrix from the base coordinate system to the workpiece coordinate system is as follows: .

[0016] Preferably, in step three, the process is automatically handled by the robotic arm program conversion software: the inverse T3 of the transformation matrix T3 is obtained through coordinate transformation of the robotic arm ablation system. -1 This process converts the tool path points in the workpiece coordinate system to path points in the base coordinate system in the CAM program; the transformation matrix T for each path point can be obtained from the position and swing angle values ​​in the APT file. i According to the transformation matrix T i The angles of each joint of the robotic arm are obtained by inverse kinematics and written into the robotic arm machining file. The robotic arm is then automatically driven to move along the trajectory points by the robotic arm machining file.

[0017] Preferably, it also includes: adding a laser-on command after each feed and a laser-off command before retraction begins.

[0018] Preferably, in step four: before the ablation process begins, the accuracy of the position of the robotic arm and the laser processing head is verified. The verification method is as follows: four optical apertures with a diameter of 1 mm and a depth of 1 mm are set on the fixture. With only the red light indicator on the control panel, the robotic arm verification program is started. The robotic arm moves sequentially along a straight line to the four optical apertures. If the position of the robotic arm and the laser processing head and the transformation matrix are accurate, the red light indicator spot can completely coincide with the optical aperture after reaching it. Otherwise, the robotic arm or the laser processing head needs to be readjusted and the transformation matrix needs to be checked.

[0019] Preferably, in step five, the cooling machine, laser generator, and control console are turned on in sequence, the converted robotic arm processing file is imported into the control console, and the processing program is started by the control console.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: I. The present invention provides a robotic laser ablation system for curved parts, which has the characteristics of high flexibility and fast processing speed. By utilizing the flexibility of the robotic arm, it can well meet the processing needs of curved parts.

[0021] II. The present invention provides a robotic laser ablation method for curved parts, which includes the construction of a robotic arm laser ablation device, the acquisition of a transformation matrix, and the laser ablation method for curved parts. This method enables efficient laser ablation processing of curved parts, and compared with traditional cutting or grinding, it has the effect of quickly removing large amounts of excess material. Since laser processing does not require direct contact with the part, the installation and positioning of the part are relatively simple. For high-precision processing, this method can be used as a roughing solution. With the help of CNC program conversion software, the CAM program can be automatically converted into robotic arm processing files, reducing the difficulty of programming robotic arm processing instructions.

[0022] Third, the robotic laser ablation method for curved parts provided by this invention is a non-contact processing method with low requirements for the rigidity of the robotic arm. Different robotic arms equipped with laser ablation devices can process curved parts of different sizes. The CNC program conversion software can match various types of robotic arms to achieve accurate program conversion. It has the characteristics of low cost and easy implementation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the robotic ablation system in this invention; Figure 2 This is a schematic diagram of the tooling and workpiece coordinate system in this invention; Figure 3 This is a schematic diagram of the workpiece coordinate system in this invention; Figure 4 This is a diagram showing the verification trajectory of the robotic arm in this invention; Figure 5 This is a flowchart of the robot laser ablation of curved surface parts in this invention; Figure 6 This is a schematic diagram of the contour of the curved part to be processed in this invention; Figure 7 This is a schematic diagram of the features of the curved surface part in this invention.

[0024] The components include: 1. Tooling adjustment platform; 2. Laser processing head; 3. Connecting plate; 4. Six-degree-of-freedom robotic arm; 5. Control console; 6. Laser generator; 7. Cooling machine; 8. Optometry port; 9. Clamping hole; 10. Curved surface part blank; 11. Tooling; 12. Curved surface part outline to be processed; 13. Irregular micro groove; 14. Cavity; 15. Irregular hole. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0026] Example 1 like Figure 1As shown, a robotic laser ablation method for curved parts includes a six-degree-of-freedom robotic arm 4, a laser processing head 2, a connecting plate 3, a control console 5, a tooling adjustment platform 1, and a laser generator 6. The laser generator 6 is connected to the laser processing head 2, and the control console 5 is connected to the six-degree-of-freedom robotic arm 4 and the laser generator 6. The six-degree-of-freedom robotic arm 4 moves according to a specific trajectory during processing. The laser processing head 2 is mounted at the end effector of the six-degree-of-freedom robotic arm 4 via the connecting plate 3. The control console 5 automates the processing process. The tooling adjustment platform 11 is used to adjust the position and orientation of the part to be processed and its tooling 11.

[0027] Example 2 like Figure 1 As shown, a robotic laser ablation method for curved parts includes a six-degree-of-freedom robotic arm 4, a laser processing head 2, a connecting plate 3, a control console 5, a tooling adjustment platform 11, and a laser generator 6. The laser generator 6 is connected to the laser processing head 2, and the control console 5 is connected to the six-degree-of-freedom robotic arm 4 and the laser generator 6. The six-degree-of-freedom robotic arm 4 moves according to a specific trajectory during processing. The laser processing head 2 is mounted at the end effector of the six-degree-of-freedom robotic arm 4 via the connecting plate 3. The control console 5 automates the processing process. The tooling adjustment platform 11 is used to adjust the position and orientation of the part to be processed and its tooling 11.

[0028] The control console 5 includes a robotic arm control module and a laser control module. The robotic arm control module is used to call and execute different robotic arm control programs to ensure that the tool coordinate system moves along a specific trajectory at a predetermined feed speed. The machining program is generated by post-processing the program written in CAM software. In the robotic arm control program, the laser processing head 2 is switched on and off by instructions. The laser control module is used to set and adjust the relevant parameters of laser ablation.

[0029] It also includes a cooler 7, which is used to reduce the temperature generated by the laser processing head 2 during use.

[0030] Example 3 like Figures 2-7 As shown, this embodiment employs a robotic laser ablation system for curved parts as described in Embodiment 2, and includes the following steps: Step 1: Determine laser ablation parameters; Step 2: CNC program development; Step 3: CNC program conversion; Step 4: Verify the accuracy of the trajectory; Step 5: Laser processing.

[0031] In step one, the laser ablation parameters are determined through ablation experiments. The ablation parameters include the robotic arm feed speed, the shape and size of the ablation area, the laser power, the spot scanning speed, and the spot scanning line interval.

[0032] The ablation test process is as follows: The starting point, ending point, and feed speed of the robotic arm are manually set in the robotic arm control module of console 5; the shape and size of the ablation area, laser power, spot scanning speed, and spot scanning line interval are set in the laser control module; after starting the robotic arm control module, the robotic arm moves along a straight line from the starting point to the ending point at the given feed speed (the given feed speed is determined by ablation parameter test verification; when the robotic arm carries the laser in a certain direction, the laser spot actually moves in a certain direction at the feed speed. If the feed speed is too high, the laser ablation marks cannot be continuously generated, resulting in intermittent processing; if the feed speed is too low, it may affect the laser ablation efficiency and ablation effect. Therefore, it is necessary to adjust the robotic arm feed speed in a timely manner according to the ablation test situation and processing requirements). Laser processing head 2 is started after the movement begins and turned off at the end; without changing the starting and ending points of the robotic arm movement, the ablation parameters are repeatedly adjusted, and the ablation depth, ablation uniformity, and ablation dust accumulation of the hard and brittle material after ablation are observed. Different ablation parameters are selected according to processing requirements.

[0033] In step two: a tooling model and a part model are established in CAM software, and a workpiece coordinate system is established on the tooling model. The theoretical distances between the workpiece coordinate system and the edge of tooling 11 are recorded as follows: , ; Compile toolpath programs in the workpiece coordinate system: When the toolpath needs to be processed in layers, the distance between layers should be consistent with the ablation depth in step one to ensure that the laser focus position is always on the surface of the area to be processed; After the program is completed, export the toolpath file in APT format.

[0034] The transformation relationship between the workpiece coordinate system and the base coordinate system is as follows: Assuming there is only translation transformation and no rotation transformation between the end effector coordinate system and the tool coordinate system, if the end effector coordinate system... Translation of axes respectively After obtaining the tool coordinate system, the transformation matrix is ​​obtained: ; Since the six-DOF robotic arm 4 is simplified to a six-DOF link, the base is defined as link 0, and so on, with the end effector being link 6. The transformation matrix from the base coordinate system to the end effector coordinate system is obtained using the improved DH method: ; in: ; The parameters in the matrix have the following meanings: a) around Axis rotation Angle, make shaft and The axes are in the same plane; b) around Axis translation ,make shaft and The axes are at the same height; c) around Axis rotation Angle, make shaft and The axes are on the same straight line; d) along Axis translation distance , making the connecting rod The origin of the coordinate system and the connecting rod The origins of their coordinate systems coincide; Therefore, the transformation matrix from the base coordinate system to the tool coordinate system Since the tool coordinate system changes during the machining process, it is assumed that there exists Given n trajectory points, each corresponding to the current tool coordinate system, then the nth trajectory point... The transformation matrix of each tool coordinate system is The inverse kinematics algorithm of the robotic arm is used to solve the joint position of the robotic arm in the current posture.

[0035] The transformation relationship between the workpiece coordinate system and the base coordinate system is as follows: (Workpiece coordinate system...) The plane is usually flush with the upper surface of the tooling, and The axis points vertically upwards; this is to obtain the translation transformation matrix. The workpiece coordinate system needs to be set first. Adjust the plane to be level and adjust... Axis and base coordinate system The axes remain parallel.

[0036] The adjustment method is as follows: When placing fixture 11, adjust the long side relative to the base coordinate system. The axes are roughly parallel; use a magnetic dial indicator holder to mount the dial indicator onto the connecting plate 3, adjust the dial indicator measuring head to the plane of fixture 11, and manually operate the robotic arm along... shaft and Move the axis and observe the change in the dial indicator. Assume the dial indicator moves along the axis. , The maximum and minimum values ​​during the axis motion process are respectively , , , Based on the difference in the dial indicator readings, adjust the base screws of the tooling 11 adjustment platform until the desired result is achieved. ,and At that time, it was assumed that the tooling platform 11 had been leveled and the workpiece coordinate system was in place. Adjust the plane to be level, and record the plane's position at the same time. Value ;in, The tolerance of the part to be processed is determined comprehensively; similarly, the dial indicator measuring head is adjusted to the long side surface of tooling 11, and the robotic arm is manually operated along... The axis moves without causing rotation of the end effector's coordinate axis. At that time, the workpiece coordinate system can be considered as , Axis and base coordinate system , Keep the axes parallel; next, align the dial indicator measuring head with the laser focus position, and operate the robotic arm to bring the dial indicator close to fixture 11 from the long and short sides respectively, without rotating the end effector coordinate axis. When the dial data abruptly changes from zero, it can be considered that the laser focus position is in contact with fixture 11. Record the position of the robotic arm when it contacts the long and short sides respectively. and ; Theoretically, the distance between the workpiece coordinate system axis and the long side of fixture 11 is , The distance between the shaft and the long side of tool 11 is Since the values ​​recorded by the robotic arm are the coordinates of the center of the end effector flange in the world coordinate system, the coordinates of the workpiece coordinate system origin in the base coordinate system can be obtained through theoretical calculations. The translation transformation matrix from the base coordinate system to the workpiece coordinate system is as follows: .

[0037] In step three, the process is automatically handled by the robotic arm program conversion software: the inverse T3 of the transformation matrix T3 is obtained through coordinate transformation of the robotic arm ablation system. -1 This process converts the tool path points in the workpiece coordinate system to path points in the base coordinate system in the CAM program; the transformation matrix T for each path point can be obtained from the position and swing angle values ​​in the APT file. i According to the transformation matrix T i The angles of each joint of the robotic arm are obtained by inverse kinematics and written into the robotic arm machining file. The robotic arm is then automatically driven to move along the trajectory points by the robotic arm machining file.

[0038] This also includes adding a laser-on command after each feed and a laser-off command before retraction begins.

[0039] In step four, before the ablation process begins, the accuracy of the positions of the robotic arm and laser processing head 2 is verified. The verification method is as follows: Four optical apertures 8 with a diameter of 1 mm and a depth of 1 mm are set on the fixture 11. With only the red light indicator on the control console 5, the robotic arm verification program is started. The robotic arm moves along a straight line to the four optical apertures 8 in sequence. If the positions of the robotic arm and laser processing head 2 are accurate and the transformation matrix is ​​accurate, the red light indicator spot can completely coincide with the optical aperture 8 after reaching it. Otherwise, the robotic arm or laser processing head 2 needs to be readjusted and the transformation matrix needs to be checked.

[0040] In step five, the cooling machine 7, the laser generator 6, and the control console 5 are turned on in sequence, the converted robotic arm processing file is imported into the control console 5, and the processing program is started by the control console 5.

[0041] The curved part blank 10 has two ends set on the tooling 11. The curved part blank 10 includes the curved part to be processed contour 12, clamping hole 9, irregular micro groove 13, cavity 14 and irregular hole 15.

[0042] Compared with the prior art, the present invention has the following advantages and beneficial effects: I. The robotic laser ablation system for curved parts provided by this invention has the characteristics of high flexibility and fast processing speed. By utilizing the flexibility of the robotic arm, it can well meet the processing needs of curved parts.

[0043] II. The present invention provides a robotic laser ablation method for curved parts, which includes the construction of a robotic arm laser ablation device, the acquisition of a transformation matrix, and the laser ablation method for curved parts. This method enables efficient laser ablation processing of curved parts, and compared with traditional cutting or grinding, it has the effect of quickly removing large amounts of excess material. Since laser processing does not require direct contact with the part, the installation and positioning of the part are relatively simple. For high-precision processing, this method can be used as a roughing solution. With the help of CNC program conversion software, the CAM program can be automatically converted into robotic arm processing files, reducing the difficulty of programming robotic arm processing instructions.

[0044] Third, the robotic laser ablation method for curved parts provided by this invention is a non-contact processing method with low requirements for the rigidity of the robotic arm. Different robotic arms equipped with laser ablation devices can process curved parts of different sizes. The CNC program conversion software can match various types of robotic arms to achieve accurate program conversion. It has the characteristics of low cost and easy implementation.

[0045] Example 4 This embodiment takes the ablation of a curved surface part made of ceramic matrix composite material as an example.

[0046] Adjust the flange plane of the robotic arm's end effector to align with the world coordinate system. The planes are parallel, and then the laser processing head is mounted onto the flange via a connecting plate. Assume the distances from the end of the laser processing head to each axis of the flange (the coordinates of the end of the laser processing head in the end effector coordinate system) are... Therefore, the coordinates of the laser focus in the end effector coordinate system can be obtained as follows: Therefore, the transformation matrix from the end effector coordinate system to the tool coordinate system can be obtained as follows: .

[0047] Place the tooling adjustment platform under the laser processing head, place the tooling on the adjustment platform, and adjust the tooling and adjustment platform to meet the workpiece coordinate system. Adjust the plane to be level and adjust... , Axis and base coordinate system , The condition is that the axes remain parallel. During measurement, the coordinates of the longer side are... The coordinates of the short side of the work are upper surface of tooling .

[0048] Assume the theoretical distances between the workpiece coordinate system and the tooling edge are respectively , The actual position of the robotic arm's end effector and the coordinates of the laser focus in the end effector's coordinate system; achievable ; ; ; That is, the translation transformation matrix from the base coordinate system to the workpiece coordinate system: .

[0049] The optimal ablation parameters for the curved part profile were obtained through ablation experiments as follows:

[0050] Under the above ablation parameter settings, the ablation depth of each layer is approximately 2 mm. Due to the large size of the rectangular ablation zone, there is virtually no oxide accumulation, resulting in good ablation uniformity. Other features, such as irregular holes, grooves, cavities, and countersunk holes, had their optimal ablation parameters determined experimentally.

[0051] Based on the experimental results, the CATIA programming parameters for the curved part contour were set as follows: tool diameter Φ6, depth of cut 2mm, width of cut 6mm, feed rate 120 mm / min, and toolpath automatically layered according to the thickness of the curved part. A Product file was created in CATIA, importing models of the tooling, curved part, and blank. A Process file was created, and an optometry program was added, moving along a rectangle to reach the four optometry holes to verify the accuracy of the robotic arm and laser processing head before machining began. Machining toolpaths were compiled according to the programming parameters of each feature. After all feature machining toolpaths were compiled, they were converted to APT files using CATIA. The APT files were then imported into the robotic arm program conversion software, and a conversion matrix was input. and The robotic arm program conversion software automatically generates the laser focus motion trajectory in the world coordinate system based on the robotic arm's geometry, adds laser processing head switching commands, and generates robotic arm processing files.

[0052] In the control panel's laser control module, set the rectangular ablation zone to 8mm in length and 6mm in width, 25μm in laser line spacing, 4000mm / s in spot movement speed, and 600W in laser power. Leave other parameters as default. Transfer the robotic arm machining file to the control panel, and then use the robotic arm control module to move the robotic arm along the trajectory to begin ablation machining of the curved part.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A robotic laser ablation system for curved surface parts, characterized in that: The system includes a six-degree-of-freedom robotic arm, a laser processing head, a connecting plate, a control console, a tooling adjustment platform, and a laser generator. The laser generator is connected to the laser processing head, and the control console is connected to both the six-degree-of-freedom robotic arm and the laser generator. The six-degree-of-freedom robotic arm moves along a specific trajectory during processing. The laser processing head is mounted on the end effector of the six-degree-of-freedom robotic arm via the connecting plate. The control console provides automated control of the processing process. The tooling adjustment platform is used to adjust the position and orientation of the workpiece and its tooling.

2. The robotic laser ablation system for curved parts according to claim 1, characterized in that: The control console includes a robotic arm control module and a laser control module. The robotic arm control module is used to call and execute different robotic arm control programs to ensure that the tool coordinate system moves along a specific trajectory at a predetermined feed rate. The machining program is generated post-processed through a program written in CAM software. In the robotic arm control program, the laser processing head is switched on and off via commands. The laser control module is used to set and adjust the relevant parameters of laser ablation.

3. The robotic laser ablation system for curved parts according to claim 1, characterized in that: It also includes a cooling unit, which is used to reduce the temperature generated by the laser processing head during use.

4. The robotic laser ablation method for curved surface parts using a robotic laser ablation system according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Determine laser ablation parameters; Step 2: CNC program development; Step 3: CNC program conversion; Step 4: Verify the accuracy of the trajectory; Step 5: Laser processing.

5. The robotic laser ablation method for curved surface parts according to claim 4, characterized in that: In step one, the laser ablation parameters are determined through ablation experiments; the ablation parameters include the robotic arm feed speed, the shape and size of the ablation area, the laser power, the spot scanning speed, and the spot scanning line interval.

6. The robotic laser ablation method for curved surface parts according to claim 5, characterized in that: The ablation test process is as follows: The starting point, ending point, and feed speed of the robotic arm are manually set in the robotic arm control module on the control console; the shape and size of the ablation area, laser power, spot scanning speed, and spot scanning line interval are set in the laser control module; after starting the robotic arm control module, the robotic arm moves along a straight line from the starting point to the ending point at the given feed speed, and the laser processing head is started after the movement begins and turned off at the end; without changing the starting and ending points of the robotic arm movement, the ablation parameters are repeatedly adjusted, and the ablation depth, ablation uniformity, and ablation dust accumulation of the hard and brittle material after ablation are observed. Different ablation parameters are selected according to processing requirements.

7. The robotic laser ablation method for curved surface parts according to claim 6, characterized in that: In step two: A tooling model and a part model are established in the CAM software, and a workpiece coordinate system is established on the tooling model. The theoretical distances between the workpiece coordinate system and the edge of the tooling are recorded as follows: 、 ; Compile toolpath programs in the workpiece coordinate system: When the toolpath needs to be processed in layers, the distance between layers should be consistent with the ablation depth in step one to ensure that the laser focus position is always on the surface of the area to be processed; After the program is completed, export the toolpath file in APT format.

8. The robotic laser ablation method for curved surface parts according to claim 7, characterized in that: Transformation relationship between workpiece coordinate system and base coordinate system: Assuming there is only translation transformation and no rotation transformation between the end effector coordinate system and the tool coordinate system, if the end effector coordinate system... Translation of axes respectively After obtaining the tool coordinate system, the transformation matrix is ​​obtained: ； Since a six-DOF robotic arm is simplified to a six-DOF link, the base is defined as link 0, and so on, with the end effector as link 6. The transformation matrix from the base coordinate system to the end effector coordinate system is obtained using the improved DH method: ； in: ; The parameters in the matrix have the following meanings: a) around Axis rotation Angle, make shaft and The axes are in the same plane; b) around Axis translation ,make shaft and The axes are at the same height; c) around Axis rotation Angle, make shaft and The axes are on the same straight line; d) along Axis translation distance , making the connecting rod The origin of the coordinate system and the connecting rod The origins of their coordinate systems coincide; Therefore, the transformation matrix from the base coordinate system to the tool coordinate system Since the tool coordinate system changes during the machining process, it is assumed that there exists Given n trajectory points, each corresponding to the current tool coordinate system, then the nth trajectory point... The transformation matrix of each tool coordinate system is The inverse kinematics algorithm of the robotic arm is used to solve the joint position of the robotic arm in the current posture.

9. The robotic laser ablation method for curved parts according to claim 7, characterized in that: Transformation relationship between workpiece coordinate system and base coordinate system: workpiece coordinate system The plane is usually flush with the upper surface of the tooling, and The axis points vertically upwards; this is to obtain the translation transformation matrix. The workpiece coordinate system needs to be set first. Adjust the plane to be level and adjust... Axis and base coordinate system The axes remain parallel.

10. A robotic laser ablation method for curved surface parts according to claim 9, characterized in that, The adjustment method is as follows: When placing the fixture, adjust the long side relative to the base coordinate system. The axes are roughly parallel; use a magnetic dial indicator holder to mount the dial indicator onto the connecting plate, adjust the dial indicator measuring head to the tooling plane, and manually operate the robotic arm along... shaft and Move the axis and observe the change in the dial indicator. Assume the dial indicator moves along the axis. , The maximum and minimum values ​​during the axis motion process are respectively , , , Based on the difference in the dial indicator readings, adjust the base screws of the tooling adjustment platform until the desired result is achieved. ,and At that time, it was assumed that the tooling platform had been leveled and the workpiece coordinate system was... Adjust the plane to be level, and record the plane's position. Value ;in, The tolerances of the parts to be processed are determined comprehensively; similarly, the dial indicator measuring head is adjusted to the long side surface of the tooling, and the robotic arm is manually operated along... The axis moves without causing rotation of the end effector's coordinate axis. At that time, the workpiece coordinate system can be considered as , Axis and base coordinate system , Keep the axes parallel; next, align the dial indicator measuring head with the laser focus position, and operate the robotic arm to bring the dial indicator close to the fixture from the long and short sides respectively, without rotating the end effector coordinate axis during the process. When the dial data changes abruptly from zero, it can be considered that the laser focus position has contacted the fixture. Record the position of the robotic arm when contacting the long and short sides respectively. and ; Theoretically, the workpiece coordinate system The distance between the shaft and the long side of the tooling is , The distance between the shaft and the long side of the tooling is Since the values ​​recorded by the robotic arm are the coordinates of the center of the end effector flange in the world coordinate system, the coordinates of the workpiece coordinate system origin in the base coordinate system can be obtained through theoretical calculations. The translation transformation matrix from the base coordinate system to the workpiece coordinate system is as follows: 。 11. The robotic laser ablation method for curved parts according to claim 7, characterized in that: In step three, the robotic arm program conversion software automatically processes the process: obtaining the inverse T3 of the transformation matrix T3 through coordinate transformation of the robotic arm ablation system. -1 This process converts the tool path points in the workpiece coordinate system to path points in the base coordinate system in the CAM program; the transformation matrix T for each path point can be obtained from the position and swing angle values ​​in the APT file. i According to the transformation matrix T i The angles of each joint of the robotic arm are obtained by inverse kinematics and written into the robotic arm machining file. The robotic arm is then automatically driven to move along the trajectory points by the robotic arm machining file.

12. The robotic laser ablation method for curved parts according to claim 11, characterized in that: Also includes: Add a laser-on command after each feed and a laser-off command before retraction begins.

13. The robotic laser ablation method for curved parts according to claim 12, characterized in that: In step four: Before the ablation process begins, the accuracy of the position of the robotic arm and the laser processing head is verified. The verification method is as follows: Four optical holes with a diameter of 1 mm and a depth of 1 mm are set on the fixture. With only the red light indicator on the control panel, the robotic arm verification program is started. The robotic arm moves along a straight line to the four optical holes in sequence. If the position of the robotic arm and the laser processing head and the transformation matrix are accurate, the red light indicator spot can completely coincide with the optical hole after reaching the optical hole. Otherwise, the robotic arm or laser processing head needs to be readjusted, and the transformation matrix needs to be checked.

14. The robotic laser ablation method for curved parts according to claim 13, characterized in that: In step five, the cooling machine, laser generator, and control console are turned on in sequence. The converted robotic arm processing file is imported into the control console, and the processing program is started by the control console.

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