A three-dimensional vision-based self-adaptive composite cutting equipment and cutting method for a sprue and a runner

Abstract

The present application relates to a kind of based on three-dimensional vision's pouring head self-adapting composite cutting equipment and cutting method, belong to the field of post-casting processing automation.The equipment includes industrial robot, three-dimensional vision measurement module, laser-flame composite cutting head and real-time correction control system.Vision module is fixed to the same mounting plate with cutting head, vision module is located outside the high-temperature area of cutting head and is provided with heat insulation and anti-splashing protection.By implementing multiple section continuous three-dimensional scanning to head root, deviation field is constructed using radial basis function interpolation, and local rescan is triggered during cutting process, and path deviation caused by thermal deformation is dynamically corrected.Composite cutting head has anti-splashing structure such as double eddy gas curtain and electromagnetic shutter, and can automatically switch pure laser or laser-assisted flame cutting process according to real-time thickness.The present application is suitable for adaptive cutting of large excess head of various cast steel, stainless steel and high chromium alloy steel castings.

Description

Technical Field

[0001] This invention relates to the field of automated equipment for post-processing of castings, specifically to an adaptive composite cutting equipment and method for gating and riser based on three-dimensional vision. Background Technology

[0002] In casting production, the removal of risers and gating gates has always been a challenging process. Currently, the industry primarily employs the following methods: One method is traditional handheld flame or plasma cutting. This method is highly dependent on the worker's experience, and the cut surface often has a lot of runners, requiring extra time for grinding. In addition, it is easy to damage the casting itself if not careful, resulting in scrap. In actual production, it often takes a skilled worker two or three minutes to cut a medium-sized riser, which is not very efficient.

[0003] Secondly, robots are used for teaching and reproducing the cutting process. This method is an improvement over manual cutting, but it has a major problem: due to shrinkage cavities, deformation, and misalignment of the sand mold, the actual dimensions of the casting blank often deviate from the theoretical model by ±3mm or even more. If the robot cuts according to a fixed teaching trajectory, the result is either an incomplete cut (too high residual material) or damage to the casting itself. Some foundries have reported that the damage rate to the casting itself caused by fixed trajectory cutting is sometimes as high as 30% or more, making subsequent welding repairs very troublesome.

[0004] Thirdly, there are some automated solutions with vision capabilities. For example, patent CN201811590243.X proposes using a two-dimensional laser profilometer to measure several key points to determine the riser position, and then planning the cutting trajectory. This method is essentially a single-step planning of "measure first, then cut," which cannot cope with path deviations caused by thermal deformation or local burrs during the cutting process.

[0005] Furthermore, while there are numerous patents for laser-flame composite cutting heads (such as CN103894745A), these patents primarily focus on the internal mechanical structure of the cutting head. They lack specific anti-contamination designs for the harsh working conditions of high dust and splashing environments in foundries. In practical use, the protective lenses of ordinary cutting heads often need to be replaced after cutting only one or two hundred pieces; otherwise, the cutting quality will significantly decrease.

[0006] In general, the industry currently lacks an integrated solution that can perceive the actual shape of the casting in real time, dynamically adjust the cutting trajectory, and simultaneously take into account both cutting efficiency and anti-contamination capabilities. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an adaptive composite cutting equipment and method for gating and riser based on three-dimensional vision. The equipment can obtain the actual shape of the riser area in real time through three-dimensional vision when there is a large dimensional deviation in the casting blank, and dynamically correct the robot trajectory during the cutting process, thereby achieving high efficiency cutting with high consistency of residual roots and low damage rate of the main body.

[0008] To solve the above-mentioned technical problems, embodiments of the present invention provide the following technical solution: an adaptive composite cutting equipment for gating and risers based on three-dimensional vision, comprising: Industrial robots are used to drive cutting heads to complete spatial movements; The three-dimensional vision measurement module is used to perform multi-section continuous scanning of the riser root to obtain a dense point cloud before cutting, and to perform local rescanning of the cutting edge in response to the trigger command of the control system during the cutting process to obtain an updated point cloud; the three-dimensional vision measurement module and the composite cutting head are independently mounted on the same mounting plate at the end of the robot, and their relative positions are fixed. The vision module is located outside the high temperature radiation and splash area of ​​the cutting head, and the vision module is equipped with a heat insulation cover and a side blowing air curtain. A laser-flame composite cutting head is used to perform pure laser cutting and / or laser-assisted flame composite cutting. The composite cutting head is equipped with an anti-splash air curtain and lens protection device, and has switchable normal cutting working distance and aerial cutting working distance. Dual-axis servo positioner, used to support and adjust the posture of castings; Enclosed safety chambers are used to isolate the cutting area; and A real-time deviation correction control system is connected to the 3D vision measurement module and the robot control cabinet; The real-time deviation correction control system is configured to: receive the point cloud of the riser region acquired by the three-dimensional vision measurement module; calculate the normal deviation of each point based on the ICP registration result of the point cloud and the theoretical numerical model; and construct a spatial deviation field using radial basis function interpolation. During the cutting process, the control system reads the correction amount from the deviation field according to the robot's current pose in each interpolation cycle and corrects the cutting trajectory in real time. Furthermore, the control system automatically triggers at least one local rescan during the cutting process, controlling the three-dimensional vision measurement module to rescan the shape of the current cut leading edge and update the deviation field with the newly acquired point cloud.

[0009] Furthermore, the real-time correction control system is configured to automatically trigger a local rescan every 20mm to 50mm of cutting length during the cutting process.

[0010] Furthermore, the composite cutting head is equipped with an anti-splash air curtain and a lens protection device; the anti-splash air curtain is a Huffman-type double vortex structure, with the main airflow used for cutting and the auxiliary airflow forming a rotating air curtain in front of the lens to blow away the splash particles; the lens chamber maintains a slight positive pressure of 0.02 to 0.05 MPa; the lens protection device is an electromagnetically driven high-speed shutter, which closes during cutting and opens within 50 ms during scanning.

[0011] Furthermore, the composite cutting head has a switchable working distance: in normal mode, the nozzle is 10-30mm away from the workpiece surface, and in aerial cutting mode, the nozzle is 200-250mm away from the workpiece surface. The two modes are automatically switched by the control system based on the protrusion of the workpiece surface detected by the sensor.

[0012] Furthermore, the three-dimensional vision measurement module adopts a blue laser, infrared binocular structured light or line laser profilometer, with a single-frame point cloud density of no less than 300,000 points and a Z-axis repeatability better than 0.03mm; the three-dimensional vision measurement module is equipped with a heat insulation cover and a side-blowing air curtain to isolate the heat radiation and splashes during the cutting process.

[0013] The present invention also proposes a method for cutting risers and gating gates using the aforementioned equipment, comprising the following steps: S1: Use a 3D vision measurement module to continuously scan no fewer than 5 characteristic sections at the root of the riser to obtain the measured point cloud; S2: Perform ICP registration between the measured point cloud and the theoretical digital model, and calculate the normal deviation of each point; S3: Based on the normal deviation, a continuous spatial deviation field is constructed using radial basis function interpolation, and a smooth transition of the cutting posture is ensured through local normal constraints; S4: Generate an initial cutting trajectory based on the theoretical numerical model, and map each interpolation point to the deviation field to obtain the corrected trajectory; S5: Control the industrial robot to cut along the corrected trajectory, and automatically trigger at least one local rescan during the cutting process to update the deviation field with the newly acquired point cloud.

[0014] Furthermore, step S1 also includes adaptive encrypted scanning: if the rate of change of deviation between two adjacent sections is detected to exceed 15%, an additional scanning section is automatically added between the adjacent sections.

[0015] Furthermore, step S5 also includes automatically selecting the cutting process based on the real-time thickness of the riser: If the real-time thickness is ≤15mm, pure laser cutting is used. The laser power is adjusted between 2kW and 20kW according to the thickness, and the cutting speed is selected within the range of 100mm / min to 600mm / min. If the real-time thickness is greater than 15mm, laser perforation is performed first, followed by flame cutting. During flame cutting, the laser maintains an auxiliary power of 500W to 1000W to continuously irradiate the cut.

[0016] Furthermore, step S5 also includes: if the three-dimensional vision measurement module detects an interference risk on the surface of the casting, the control system automatically switches the composite cutting head to the aerial cutting mode. At this time, the distance between the nozzle and the workpiece is 200mm to 250mm, so that the surface finish of the cut at a distance of 200mm reaches within Ra30.

[0017] Furthermore, the industrial robot has a repeatability accuracy better than ±0.05mm and a protection level of not less than IP67; the three-dimensional vision measurement module has a single scan point cloud density of not less than 300,000 points and a Z-axis repeatability accuracy better than 0.03mm.

[0018] The beneficial effects of the above-described technical solution of the present invention are as follows: (1) The cutting accuracy is significantly improved. When there is a large dimensional deviation in the casting blank, the present invention uses three-dimensional vision to perceive the actual shape in real time and combines it with online correction, which greatly improves the consistency of the residual root height, reduces the standard deviation significantly, and makes the damage rate of the body close to zero. Basically, there is no need for welding repair and secondary grinding, which significantly improves the cutting quality.

[0019] (2) A "thermal compensation" mechanism is introduced during the cutting process. Existing technologies mostly involve a one-time measurement before cutting, with no further adjustments during the cutting process, which cannot cope with the effects of thermal deformation. This invention uses repeated scanning at short intervals and real-time trajectory correction during the cutting process, effectively compensating for path deviation caused by local thermal deformation, significantly reducing the risk of cutting off the root of thick risers, and greatly improving the stability and reliability of the cutting process.

[0020] (3) The anti-contamination capability of the cutting head has been greatly improved. Thanks to the comprehensive protection design of the dual vortex air curtain, lens micro positive pressure protection and electromagnetic high-speed shutter, the cutting head can operate stably for a long time in the harsh working conditions of high dust and high splash in the foundry workshop. The replacement cycle of the protective lens has been significantly extended. There has been no decline in cutting quality due to contamination during continuous operation, and the equipment maintenance frequency has been greatly reduced.

[0021] (4) Significant advantages in overall efficiency. For large-diameter, thick risers, the laser-flame composite process can significantly shorten the cutting time compared to pure laser cutting; compared to pure flame cutting, it not only cuts faster but also eliminates the need for subsequent grinding processes, thus increasing the overall processing efficiency several times over and significantly reducing the time per piece.

[0022] (5) Excellent synergistic effect. In conventional understanding, long-distance cutting often leads to a significant decrease in cutting quality. However, this invention effectively compensates for optical path jitter and focus drift at long distances through a thermal rescanning mechanism, enabling long-distance aerial cutting to still maintain good cross-sectional quality. This synergistic effect cannot be achieved by using long-distance cutting alone or thermal compensation alone, fully demonstrating the organic synergistic effect between the various technical features of this invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the adaptive composite cutting equipment for gating and risers of the present invention.

[0024] Figure 2 A schematic diagram of the main process for 3D visual scanning and bias field construction.

[0025] Figure 3 This is a schematic diagram of the cross-sectional structure of a laser-flame composite cutting head.

[0026] Figure 4 This is a schematic diagram of the path planning method when the robot's end-effector scans the root of the riser.

[0027] Figure 5 This is a partially enlarged structural diagram of the nozzle of the composite cutting head.

[0028] Figure 6 These are partial comparison photos of the riser root area before and after cutting in Example 1.

[0029] Figure 7 Box plots showing the root height distribution of Example 1 and Comparative Examples 1-4.

[0030] Figure 8 This is a comparison diagram of the distribution of infrared thermal images of the top surface during the cutting process between Example 1 and Comparative Example 2.

[0031] Figure 9 This is a diagram showing the compensation effect of real-time thermal micro-scanning.

[0032] Figure 10 This is a trend chart showing the surface finish of the cut surface of the equipment of this invention after 500 hours of continuous operation in the foundry. Detailed Implementation

[0033] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0034] Example 1: Cutting risers for high-chromium alloy steel wear-resistant parts This embodiment describes a high-chromium alloy steel wear-resistant liner with a riser diameter of approximately 280 mm and a height of approximately 180 mm. The dimensional deviation of the blank is between +4.2 mm and -3.8 mm, which is considered a relatively large deviation.

[0035] The equipment configuration is as follows: Robot 7: ABBIRB6700-245, 6 axes, 245kg load.

[0036] 3D vision measurement module 5: SICKRuler3000, scanning range 500×400mm, point cloud accuracy 0.05mm.

[0037] Laser: AKS-6000, 6kW fiber laser.

[0038] Flame system: acetylene + oxygen, maximum cutting thickness nominally 120mm.

[0039] Positioner 1: Dual-axis servo, 2.5-ton load capacity.

[0040] Control system: Beckhoff CX2043, running TwinCAT3, interpolation period set to 2ms.

[0041] The actual cutting steps are as follows: The first step is a global scan. Positioner 1 rotates casting 2 to 0 degrees, and robot 7, carrying 3D vision measurement module 5, scans the entire top surface of casting 2 at a speed of 50 mm / s, taking approximately 12 seconds to obtain a point cloud of about 1.5 million points. The software then identifies the approximate location of the riser from this point cloud.

[0042] The second step is detailed modeling. Robot 7 automatically planned five scanning sections perpendicular to the riser centerline, with each section spaced 40mm apart, a scanning width of 60mm, and a point spacing of approximately 0.15mm. After scanning, the model was aligned with the theoretical model using the ICP algorithm, and then the deviation field was generated using radial basis function interpolation. This step took approximately 0.8 seconds.

[0043] The third step is to generate the corrected trajectory. Based on the theoretical numerical model, the system generates a cutting path spiraling downwards from the outer edge of the riser towards the root, with a total of 384 interpolation points. Then, the deviation field is mapped onto each point to obtain the corrected robot pose sequence.

[0044] Step four: Begin cutting. Visual measurements show the riser top wall thickness is approximately 22mm, and the root is approximately 48mm. The system decides to first use a 6kW laser at a speed of 400mm / min for pure laser cutting at the top, pausing when 15mm remains to the root. Next, the laser pulses through holes (approximately 0.3 seconds), then switches to flame cutting with an acetylene flow rate of 40L / min, oxygen flow rate of 150L / min, and a speed of 220mm / min, while simultaneously reducing the laser power to 800W for auxiliary heating. During the cutting process, every 25mm of cutting is completed, robot 7 pauses for 0.15 seconds, allowing the 3D vision measurement module 5 to quickly scan the leading edge of the current cut and update the deviation field. This thermal compensation is very effective, especially at the root, where the actual path deviates from the initial planned path by approximately 1mm. After compensation, the actual cut follows the root radius precisely.

[0045] Step 5, self-inspection. After the cutting is completed, the 3D vision measurement module 5 scans the cross-section again. A simple neural network model determines that the maximum height of the residual root is 1.8mm, which is less than the threshold of 2mm, so no further cutting is needed.

[0046] The entire process took: 15 seconds for scanning (including global and fine-grained scanning), 0.8 seconds for calculation, and 42 seconds for cutting, for a total of 57.8 seconds. The measured average residual root height was 1.5 mm with a standard deviation of 0.3 mm, and the cross-sectional surface finish was Ra26.5. No workpieces showed any damage to their body.

[0047] Example 2: Alternative to Linear Laser Profilometer This embodiment is basically the same as Embodiment 1, except that the structured light camera is replaced with a line laser profilometer (LMIGocator3550). Since the line laser can only obtain the contour lines, it needs to be coordinated with the robot 7's movement to construct a 3D point cloud, thus the scanning time is slightly longer, increasing the overall cycle time to 68 seconds. The standard deviation of the residual root is 0.5mm, and the surface finish is Ra28.5. Although slightly inferior to the structured light solution, it is sufficient for applications with less stringent accuracy requirements, and the cost of the line laser is relatively low.

[0048] Example 3: Comparison without hot rescan This embodiment intentionally disables the hot rescanning function during the cutting process, meaning it only scans once before cutting and then does not update the deviation field. Other conditions are the same as in Embodiment 1. The results showed that the deviation was not significant when cutting to the middle of the riser, but at the root, due to prolonged heating, casting 2 underwent slight local deformation, and the maximum deviation between the actual cut position and the preset trajectory reached 1.7 mm. The final average residual root height was 2.1 mm, with a standard deviation increasing to 1.1 mm, and 4% of the workpieces showed localized cuts to the body (marks deeper than 0.5 mm). This indicates that hot rescanning is crucial for risers with large wall thicknesses and is not optional.

[0049] Example 4: Shortening the air distance In this embodiment, the overhead cutting distance was reduced from 220mm to 120mm, bringing the nozzle 19 closer to the casting 2. Other conditions remained unchanged. The resulting residual quality was slightly better (1.7±0.4mm), but the cycle time increased (78 seconds) because the robot 7 needed to be more careful to avoid protrusions on the surface of the casting 2. Furthermore, approximately 3% of the workpieces experienced minor nozzle collisions during the test (fortunately, no equipment damage was caused). This embodiment illustrates that while shorter cutting distances offer slightly better quality, considering both safety and efficiency, an overhead cutting distance of 200mm or more is more advantageous, provided that thermal compensation is implemented to ensure quality.

[0050] Example 5: Ductile iron multi-riser gearbox housing This embodiment is a more realistic example of mass production. The workpiece is a ductile iron gearbox housing with 6 risers, a diameter between 120mm and 180mm, a height of 80-120mm, and a blank deviation of approximately ±3.5mm.

[0051] In terms of equipment, a dual-station rotary exchange worktable was added to the existing embodiment 1. This allows for simultaneous loading and unloading at one station while the other station is cutting, without interference.

[0052] Considering that the riser thickness of ductile iron is relatively uniform, generally between 15-20mm, the system automatically selected the pure laser cutting mode, without enabling the flame. The laser power was set to 4kW, and the speed to 450mm / min.

[0053] In terms of scanning strategy, since the six risers are scattered, the system automatically plans the shortest path and scans each riser in turn, which takes a total of 15 seconds.

[0054] The entire process cycle is broken down as follows: Loading and unloading (in parallel with cutting): 20 seconds; Global scan to identify risers: 8 seconds; Fine scanning of each riser: 15 seconds; Deviation field calculation: 0.6 seconds; Path generation: 0.4 seconds; Cutting 6 risers: 68 seconds; Self-check: 6 seconds; The total cycle time was 98 seconds. The average height of the residual roots of the six risers after cutting was 1.4 mm, with a standard deviation of 0.3 mm, and the surface finish was Ra26.8. Compared to the original manual flame cutting (about 8 minutes per workpiece, plus additional grinding), the efficiency was increased by about 5 times.

[0055] Example 6: Continuous pressure test of 50 pieces To verify the stability of the equipment, we continuously cut 50 pieces of high-chromium alloy steel liners from the same batch (i.e., the workpieces in Example 1), each using the exact same process parameters. The results are as follows: Mean height of residual roots: 1.6 mm, standard deviation: 0.4 mm; The standard deviation of residual material (inter-piece variation) among 50 pieces: only 0.22 mm; The cutting time for the first piece was 58.2 seconds, and for the 50th piece it was 59.1 seconds, with almost no decay. Average surface finish Ra: 27.4; Pass rate: 100%, not a single item required recutting; This indicates that the equipment has good batch consistency and the process parameters are also quite robust.

[0056] Example 7: Durability Verification of Continuous Operation in the Workshop This embodiment primarily tests the reliability of the equipment in a real foundry environment. The dust concentration in the workshop was approximately 8-12 mg / m³, the temperature was 28-42℃, and the humidity was 45-65%. We operated it continuously for 4 weeks, 6 days a week, with two shifts per day, cutting an average of about 300 pieces per day, for a total of about 7200 pieces.

[0057] During this period, the protective lens 31 was replaced only once as a precaution (at the 3800th replacement). The electromagnetic high-speed shutter 34 was opened and closed approximately 14,400 times without any malfunctions. There were two instances of scanning failure due to lens contamination, both occurring after a large-scale sand cleaning in the workshop when dust concentration suddenly increased. These were resolved by manually wiping with a lint-free cloth. The overall trouble-free operating time of the equipment reached 500 hours.

[0058] This result verifies that the anti-splash measures of the present invention are indeed effective, and the lens replacement cycle is extended by nearly 20 times compared to the conventional cutting head 3 (usually around 200 pieces). The reliability of the electromagnetic high-speed shutter 34 has also been proven.

[0059] Example 8: Integrated installation of vision module and cutting head (side-mounted connection) This embodiment is basically the same as Embodiment 1, except that the three-dimensional vision measurement module 5 is not independently cantilevered, but is fixed to the same flange as the laser-flame composite cutting head 3 via a rigid mounting plate. The three-dimensional vision measurement module 5 is located to the side and rear of the cutting head 3, forming an integrated vision-cutting unit. The vision sensor uses a high-precision line laser profilometer, which performs high-speed scanning of the surface of the casting 2 through the laser triangulation principle.

[0060] To prevent damage to the 3D vision measurement module 5 from high temperatures and splashes during the cutting process, the following protective measures were taken: The 3D vision measurement module 5 is encased in a stainless steel heat shield, with a ceramic fiber heat insulation layer attached to the inside. An independent lateral compressed air curtain is set in front of the lens of the 3D vision measurement module 5, which continuously blows air during cutting to form a protective curtain; An air gap of at least 50mm is left between the sensor and the cutting head 3 to prevent heat conduction.

[0061] Since the relative position between the 3D vision measurement module 5 and the cutting head 3 is constant, the system does not require additional tool coordinate calibration, and the scan data can be directly used for cutting trajectory correction. During the cutting process, the "hot rescan" strategy is also executed: after every 20-50mm of cutting length, the robot 7 pauses for 0.1-0.2 seconds, and the 3D vision measurement module 5 scans the shape of the current cutting edge again to update the deviation field.

[0062] The test results show that, under this integrated installation method (with the 3D vision measurement module 5 located outside the high-temperature area), the sensor surface temperature remained below 55°C, and no measurement drift or damage occurred due to overheating. The cutting cycle time was comparable to that of Example 1 (58.5 seconds), the average residual root height was 1.6 mm, the standard deviation was 0.35 mm, and the cross-sectional surface finish was Ra27.5, meeting the technical agreement requirements.

[0063] Example 9 Verification of riser cutting for bolster / side frame This embodiment focuses on the cutting verification of K6 bolster and side frame cast steel parts (B+ grade steel) for railway freight cars. Casting 2 has multiple risers and gating gates distributed at different spatial angles (top, side and root), with a blank deviation of ±3.5mm.

[0064] The equipment configuration is as follows: Robot 7: ABBIRB6700-245 / 2.8, repeatability ±0.05mm, protection rating IP67.

[0065] Laser: Chuangxin MFSC-2000W fiber laser (2000W).

[0066] Cutting head 3: FHT2000 composite cutting head (side-mounted to the vision module).

[0067] Gases: cut oxygen purity 99.95%, acetylene flow rate 4 m³ / H.

[0068] Cutting strategy: Global Scan: Identifies the location of all risers and ingates on the bolster / side frame.

[0069] Refined modeling and deviation field construction: Multi-section scanning is performed on the root of each riser, and deviation field is generated by RBF interpolation.

[0070] Adaptive cutting: Pure laser (2000W) is used for thickness ≤15mm; laser perforation + flame cutting is used for thickness >15mm, with laser-assisted power of 800W.

[0071] Hot rescan: Trigger a local rescan every 30mm to update the deviation field.

[0072] Acceptance results (30 samples): Single piece cutting time: All parts of the bolster meet the agreement requirements (maximum 230s / piece), and the side frame is 220s / piece.

[0073] Root length range: 2.5~3.5mm.

[0074] Cross-sectional smoothness: Ra26~28.

[0075] Body damage rate: 0%.

[0076] Comparative advantages: High-quality removal of thick risers was achieved at a relatively low power of 2000W, verifying the compatibility of this invention with the "low-power laser + flame" composite route.

[0077] Comparative Example 1: Fixed trajectory with no visual cutting For comparison, the same robot 7 was used, but its vision function was turned off, and it was cut along a fixed trajectory using the traditional teaching method. Results: residual root height 6.2±2.5mm, body damage rate 48% (nearly half of the workpieces required welding repair), single piece cutting time 110 seconds (because the operator had to stop frequently to check).

[0078] Comparative Example 2 CN201811590243.X Method Reproduction According to the patented method, a two-dimensional laser profilometer is used to measure three points at the root of the riser, fit the center and radius of the circle, and then plan the cutting trajectory. Results: residual root height 3.8±1.8mm, body damage rate 12%, single-piece cutting time 95 seconds. Especially when the blank deviation direction is inconsistent with the assumption (for example, the riser is not only eccentric but also tilted), it is easy to damage the body.

[0079] Comparative Example 3: Pure Laser Cutting The entire process uses only a 6kW laser cutter without switching flames. Results: cycle time 102 seconds, surface finish Ra42, but slag buildup at the riser root requires manual polishing. While cleaner than pure flame cutting, it is less efficient than the composite process of this invention.

[0080] Comparative Example 4: Pure Flame Cutting Robot 7, equipped with a standard flame torch, without a laser module or vision system, cuts along a fixed trajectory. Results: residual root height 7.5±2.2mm, damage rate 62%, cycle time 165 seconds, surface finish Ra92, each workpiece requiring an additional 2-3 minutes of grinding. This is the worst solution among all options.

[0081] The working process and principle of the present invention are described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of the adaptive composite cutting equipment for gating and rising gates of the present invention. In the overall structure of the adaptive composite cutting equipment for gating and rising gates of the present invention, an industrial robot 7 (preferably a six-axis industrial robot) is mounted on the base 6 to drive the cutting head 3 to complete spatial movement. Its repeatability is better than ±0.05mm, and its protection level is not lower than IP67.

[0082] The robot 7 has a 3D vision measurement module 5 and a laser-flame composite cutting head 3 independently mounted on the same flange plate at its end. Their relative positions are fixed, and the vision module 5 is located to the side and rear of the cutting head 3, equipped with a heat shield and a side-blowing air curtain to isolate heat radiation and splashes during the cutting process. The 3D vision measurement module 5 preferably uses a blue laser (wavelength approximately 450nm) or infrared binocular structured light, with a single scan point cloud density of no less than 300,000 points and a Z-axis repeatability better than 0.03mm.

[0083] The laser-flame composite cutting head 3 integrates a fiber laser module (power range 2kW~20kW) and an oxygen-gas flame module (gas can be acetylene or propane). The cutting head 3 is equipped with a coaxial auxiliary air blowing port and a side air curtain for performing pure laser cutting and / or laser-assisted flame composite cutting.

[0084] The front end of the cutting head 3 is equipped with a copper spiral anti-splash cover 29, the inner surface of which has a spiral flow channel 30 to guide the splash particles outward; the lens chamber 23 is equipped with a micro positive pressure air passage, and the pressure is maintained at 0.02~0.05MPa; an electromagnetically driven high-speed shutter 34 is installed in front of the sensor lens 33. The shutter 34 is closed during cutting and opens rapidly within 50ms during scanning.

[0085] A dual-axis servo positioner 1 is positioned in front of robot 7. It has a load-bearing capacity of no less than 1.5 tons and a repeatability of ±0.05mm. It is used to support and adjust the posture of casting 2, which is clamped on positioner 1.

[0086] The entire equipment is surrounded by a closed safety chamber 10 to isolate the cutting area. The chamber walls are equipped with observation windows 9, safety doors 8, and dust removal interfaces 11. The ceiling inside the chamber is also equipped with explosion-proof lighting 13 and industrial monitoring cameras 12. Additionally, explosion-proof sensors 4 are installed inside the chamber to monitor the oxygen and combustible gas concentrations in the cutting area in real time, ensuring operational safety. Furthermore, the equipment includes a real-time deviation correction control system connected to the 3D vision measurement module 5, robot control cabinet 14, and electrical control cabinet 15.

[0087] Unlike the common "scan first, then cut" method, this invention continuously uses 3D vision information to correct the trajectory during the cutting process. Specifically, before the actual cutting, robot 7, carrying sensor 5, scans at least five sections at different heights along the root of the riser. Each section acquires a continuous contour point cloud with a width of at least 50mm. If the deviation rate between two adjacent sections exceeds 15%, the system automatically increases the number of scanning sections, up to a maximum of nine, to ensure that complex local deformations are captured.

[0088] After ICP registration of the acquired point cloud with the theoretical digital model of casting 2, a continuous deviation field D(x,y,z) is constructed using the radial basis function (RBF) interpolation method. This deviation field not only records the normal offset at each spatial position but also ensures a smooth transition of the cutting posture through local normal constraints. During the movement of robot 7, the control system reads the correction amount from the deviation field according to the current pose in each interpolation cycle (usually ≤4ms) and performs online smoothing on the corrected path to keep the speed fluctuation of robot 7 within 5%.

[0089] Meanwhile, a key control mechanism is implemented during the cutting process: after each cut of approximately 20mm to 50mm, robot 7 automatically pauses for 0.1 to 0.2 seconds, allowing sensor 5 to rescan the morphology of the current kerf leading edge and update the deviation field. This "thermal rescanning" mechanism compensates for path deviations caused by localized thermal deformation. Actual tests show that without this compensation, the maximum deviation between the actual kerf position and the theoretical position can reach over 1.5mm when cutting to the riser root; however, with thermal rescanning, this deviation can be controlled within 0.4mm.

[0090] Secondly, unlike ordinary laser cutting heads, the composite cutting head 3 of this invention can automatically switch working modes according to the thickness of different parts of the riser. The specific logic is as follows: When the real-time thickness measured by 3D vision does not exceed 15mm, pure laser cutting is used. The laser power is adjusted between 2kW and 20kW according to the thickness, and the cutting speed is selected within the range of 100mm / min to 600mm / min.

[0091] When the thickness exceeds 15mm, especially when there are large rounded corners at the riser root, switch to flame-assisted cutting mode. It's worth noting that during flame cutting, the laser is not completely turned off, but maintains a low power (approximately 500W–1000W) to continuously irradiate the cut, serving to assist in preheating and stabilize the molten pool. This combination of "laser-assisted flame" results in faster cutting speeds and significantly reduced slag buildup on the cut surface compared to pure flame cutting.

[0092] If sensor 5 detects interference on the surface of casting 2, the system will automatically switch to "aerial cutting mode." In this mode, the distance between nozzle 19 and the workpiece is increased to 200mm-250mm to avoid collision. In this mode, cutting quality can still be guaranteed by appropriately increasing the laser power or flame oxygen pressure. Actual measurements show that the surface finish of the cut at a distance of 200mm can still reach within Ra30.

[0093] Furthermore, considering the unavoidable dust and splashes in the foundry workshop, this invention incorporates several targeted designs in the cutting head 3: A Huffman-style double vortex air curtain is arranged around the nozzle 19, which includes an inner vortex chamber 20 and an outer vortex chamber 21. The main airflow 17 is accelerated by the inner vortex chamber 20 and used for cutting. The auxiliary vortex airflow 16 forms a rotating air curtain in front of the lens 22 after passing through the outer vortex chamber 21, and is ejected through the air curtain outlet 18 to blow away the splash particles.

[0094] The lens chamber 23 is kept under a slight positive pressure (around 0.03 MPa), and clean gas is introduced through the protective air inlet 24 (micro-pores) to prevent external dust from entering.

[0095] An electromagnetically driven high-speed shutter 34 is installed in front of the sensor lens 33. This shutter is controlled by an electromagnetic actuator 26 (energized) to close the shutter blades 25, and by an electromagnetic actuator 28 (de-energized) to open the shutter blades 27, with a response time of less than 50ms. During laser or flame cutting, the shutter 34 remains closed, only opening rapidly when scanning is required. This prevents lens contamination even in the presence of strong light radiation or splashes. In actual use, this shutter 34 has undergone over ten thousand opening and closing tests without any malfunctions.

[0096] Figure 2 The main process of 3D visual scanning and deviation field construction is demonstrated. Figure 2The image is divided into four sub-images from left to right: 2a shows robot 7 carrying sensor 5 scanning multiple cross-sections along the root of the riser (five scanning lines of different heights are marked with dashed lines in the image); 2b shows the deviation between the contour point cloud (gray points) collected on a single cross-section and the theoretical digital model contour (solid line); 2c shows the effect after superimposing the point clouds of multiple cross-sections and performing ICP registration; 2d shows the continuous deviation field generated by radial basis function interpolation. Different gray levels in the image represent the magnitude of the deviation, with darker gray indicating positive deviation (material excess) and brighter gray indicating negative deviation (material deficiency).

[0097] Figure 3 This is a cross-sectional structural diagram of the laser-flame composite cutting head 3. Several key components are marked in the diagram: (a) is the structural layout of the Huffman-type double vortex air curtain. The arrows indicate the direction of the main airflow 17 and the auxiliary swirling airflow 16. After passing through the inner swirling chamber 20 and the outer swirling chamber 21 respectively, they are ejected from the air curtain outlet 18; (b) is the micro-positive pressure protective gas inlet 24 (micro-pore) of the lens chamber 23; (c) is the electromagnetically driven high-speed shutter. The left side shows the shutter blade 25 (closed) in the state of the electromagnetic driver 26 (powered on), and the right side shows the shutter blade 27 (open) in the state of the electromagnetic driver 28 (power off); (d) is the copper spiral splash guard 29 installed at the front end of the cutting head 3. Its inner surface has a spiral flow channel 30 (made of copper) that can guide the splash particles outward.

[0098] Figure 4 The diagram illustrates the path planning method of the robot's end effector sensor 5 when scanning the root of a riser. Using a typical circular riser as an example, the sensor scanning trajectory is drawn with dashed lines: First, a transverse scan is performed along the riser's height at five different heights (labeled Z1 to Z5 in the diagram), each scanning section covering an area extending approximately 30mm outward from the riser root. If the system detects a deviation rate exceeding 15% between two adjacent sections, it automatically inserts an additional scanning section in between (indicated by dashed lines in the diagram). This "adaptive encryption" scanning strategy ensures complete capture of complex morphologies while avoiding unnecessary scanning time waste.

[0099] Figure 5This is a partially enlarged structural diagram of the nozzle 19 of the composite cutting head 3, overlaid with simulation results of the air curtain flow field. The diagram shows that the main airflow channel 35 (cutting gas) inside the nozzle 19 is used to deliver auxiliary gas for the laser or flame (thick arrow). Simultaneously, air curtain channels 36 (left) and 37 (right) are set around the nozzle 19, spraying towards the center from the left and right sides at an inclined angle, forming a rotating airflow that finally exits from the nozzle outlet 38. The flow field simulation cloud map on the right shows the blocking effect of the air curtain on splashed particles; most of the molten slag particles 40 (small gray dots) are blown away by the lateral airflow before reaching the lens area (as shown by airflow 41 deflecting the molten slag particles outward to protect the optical lens). Furthermore, Figure 5 The installation position of the electromagnetic high-speed shutter 34 (closed state) is also marked: the shutter 34 is located at the front of the sensor lens 33 and is driven by a set of parallel electromagnetic drivers 39 with a response time of less than 50ms; the position of the collimation protection lens 31 and the focusing lens 32 are also shown in the figure.

[0100] Figure 6 These are partial comparison photos of the riser root area before and after cutting in Example 1. In 6(a), the original riser shape on casting 2 can be seen, with obvious burrs and local protrusions at the riser root; 6(b) is the cross-section after cutting, which is flat with almost no slag, and it can be clearly seen that the height of the residual root is controlled within a very small range.

[0101] Figure 7 These are box plots showing the residual root height distribution for Example 1 and Comparative Examples 1-4. The horizontal axis represents different schemes (Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4), and the vertical axis represents the residual root height (in mm). Each box plot provides the minimum, lower quartile, median, upper quartile, and maximum values ​​for 30 samples. It can be seen that Example 1 has the lowest median (approximately 1.5 mm) and a very narrow box (interquartile range less than 0.4 mm), while the boxes in the comparative examples are significantly wider, and the medians are much higher.

[0102] Figure 8 The distribution of infrared thermograms on the top surface during the cutting process (at a heat flux density of approximately 300 W / cm²) of Example 1 and Comparative Example 2 is compared. (a) is the thermogram of Example 1, where the temperature distribution is uniform overall, with the high-temperature area concentrated near the root of the riser; (b) is the thermogram of Comparative Example 2, where obvious local hot spots (bright white areas) can be seen, indicating local overheating caused by poor exhaust of high-temperature gas.

[0103] Figure 9This diagram illustrates the compensation effect of real-time thermal micro-scanning. The horizontal axis represents the length of the cutting path (measured from the outer edge of the riser top, in mm), and the vertical axis represents the normal offset of the actual cut position relative to the theoretical path (in mm). The solid gray line indicates that without thermal compensation, the offset gradually increases with the cutting depth, reaching approximately 1.2 mm at the root. The dashed black line indicates that with thermal compensation, a rescan and correction are triggered every 25 mm, and the residual offset is always kept within 0.3 mm.

[0104] Figure 10 This is a trend chart of the surface finish of the cut surface after the equipment of this invention has been running continuously for 500 hours in a foundry. The horizontal axis represents the cumulative number of cut pieces (unit: pieces), and the vertical axis represents the surface finish Ra value (unit: μm). As can be seen in the chart, the Ra value is basically stable between 26 and 30 for the first 3800 pieces. At the 3800th piece, we preventatively replaced the protective lens 31, after which the Ra value returned to its initial level. In contrast, a dashed line is also drawn in the chart, representing the typical trend of a conventional cutting head 3 (without anti-splash design), where the Ra value begins to rise significantly after approximately 200 pieces.

[0105] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A three-dimensional vision-based adaptive composite cutting equipment for gating and riser gates, characterized in that, include: Industrial robot (7) is used to drive the cutting head to complete spatial movement; The three-dimensional vision measurement module (5) is used to perform multi-section continuous scanning of the riser root before cutting to obtain dense point cloud, and to perform local re-scanning of the cutting edge in response to the trigger command of the control system during cutting to obtain updated point cloud. Laser-flame composite cutting head (3) is used to perform pure laser cutting and / or laser-assisted flame composite cutting. The composite cutting head is equipped with an anti-splash air curtain and lens protection device, and has a switchable normal cutting working distance and aerial cutting working distance. A dual-axis servo positioner (1) is used to carry and adjust the posture of castings; A closed safety chamber (10) is used to isolate the cutting area; The real-time correction control system is connected to the three-dimensional vision measurement module (5) and the robot control cabinet (14); The real-time correction control system is configured to: receive the point cloud of the riser region collected by the three-dimensional vision measurement module (5), calculate the normal deviation of each point based on the ICP registration result of the point cloud and the theoretical numerical model, and construct a spatial deviation field by radial basis function interpolation; during the cutting process, the real-time correction control system reads the correction amount from the deviation field according to the robot's current pose in each interpolation cycle and corrects the cutting trajectory in real time; and the real-time correction control system automatically triggers at least one local rescan during the cutting process, controls the three-dimensional vision measurement module (5) to scan the shape of the current cut front edge again, and updates the deviation field with the newly acquired point cloud.

2. The equipment according to claim 1, characterized in that, The real-time correction control system is configured to automatically trigger a local rescan every 20mm to 50mm of cutting length during the cutting process.

3. The equipment according to claim 1, characterized in that, The composite cutting head (3) is equipped with an anti-splash air curtain and a lens protection device. The anti-splash air curtain is a Huffman-type double vortex structure. The main airflow is used for cutting, and the auxiliary airflow forms a rotating air curtain in front of the lens to blow the splash particles away. The lens chamber (23) maintains a slight positive pressure of 0.02 to 0.05 MPa. The lens protection device is an electromagnetically driven high-speed shutter (34). The shutter is closed during cutting and opens within 50 ms during scanning.

4. The equipment according to claim 1, characterized in that, The composite cutting head (3) has a switchable working distance: in normal mode, the nozzle (19) is 10-30mm away from the workpiece surface, and in aerial cutting mode, the nozzle (19) is 200-250mm away from the workpiece surface. The two modes are automatically switched by the control system based on the protrusion of the workpiece surface detected by the sensor.

5. The equipment according to claim 1, characterized in that, The three-dimensional vision measurement module (5) uses a blue laser, infrared binocular structured light or line laser profilometer, with a single frame point cloud density of no less than 300,000 points and a Z-axis repeatability better than 0.03mm; the three-dimensional vision measurement module (5) is equipped with a heat insulation cover and a side blowing air curtain to isolate the heat radiation and splashes during the cutting process.

6. A method for cutting risers and gating gates using the equipment described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Use the three-dimensional vision measurement module (5) to continuously scan no less than 5 characteristic sections of the riser root to obtain the measured point cloud; S2: Perform ICP registration between the measured point cloud and the theoretical digital model, and calculate the normal deviation of each point; S3: Based on the normal deviation, a continuous spatial deviation field is constructed using radial basis function interpolation, and a smooth transition of the cutting posture is ensured through local normal constraints; S4: Generate an initial cutting trajectory based on the theoretical numerical model, and map each interpolation point to the deviation field to obtain the corrected trajectory; S5: Control the industrial robot (7) to cut along the corrected trajectory, and automatically trigger at least one local rescan during the cutting process to update the deviation field with the newly acquired point cloud.

7. The method according to claim 6, characterized in that, Step S1 also includes adaptive encrypted scanning: if the rate of change of deviation between two adjacent sections is detected to exceed 15%, an additional scanning section is automatically added between the adjacent sections.

8. The method according to claim 6, characterized in that, Step S5 also includes automatically selecting the cutting process based on the real-time thickness of the riser: If the real-time thickness is ≤15mm, pure laser cutting is used. The laser power is adjusted between 2kW and 20kW according to the thickness, and the cutting speed is selected within the range of 100mm / min to 600mm / min. If the real-time thickness is greater than 15mm, laser perforation is performed first, followed by flame cutting. During flame cutting, the laser maintains an auxiliary power of 500W to 1000W to continuously irradiate the cut.

9. The method according to claim 6, characterized in that, Step S5 also includes: if the three-dimensional vision measurement module (5) detects that there is an interference risk on the surface of the casting, the control system automatically switches the composite cutting head (3) to the aerial cutting mode, at which time the distance between the nozzle (19) and the workpiece is 200mm to 250mm.

10. The method according to claim 6, characterized in that, The industrial robot (7) has a repeatability accuracy better than ±0.05mm and a protection level of not less than IP67; the three-dimensional vision measurement module (5) has a single scan point cloud density of not less than 300,000 points and a Z-axis repeatability accuracy better than 0.03mm.

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