A drill pipe weld crown polishing apparatus and method

Abstract

The application discloses a kind of drill pipe weld round polishing equipment and method.The equipment includes bed base 1, guide rail 2, sliding table 3, drill pipe rotation driving mechanism, adaptive floating polishing head mechanism, weld automatic identification positioning device, polishing feed control mechanism, on-line detection device, programmable control system 16 and scrap removal device.Adaptive floating polishing head mechanism realizes constant force polishing and radial floating by rocker arm 8 hinged structure and constant force cylinder 10, and polishing motor 13 drives rough grinding wheel 11 and fine grinding wheel 12 to realize stage polishing.Weld automatic identification positioning device automatically identifies weld position and excess height by displacement sensor 14 point-by-point scanning.On-line detection device monitors roughness and diameter in real time, and detection result is fed back to programmable control system 16 to form double closed-loop control (rough grinding intermediate detection closed loop and fine grinding on-line detection closed loop).The method includes complete closed-loop steps of drill pipe clamping, weld identification, parameter setting, rough grinding, rough grinding intermediate detection, fine grinding, fine grinding on-line detection, result determination and feedback adjustment.The application realizes automatic quantitative polishing of drill pipe weld round, and has good polishing quality consistency, high efficiency and low labor intensity.

Description

Technical Field

[0001] This invention relates to the field of oil drill pipe processing equipment technology, specifically to a drill pipe weld outer circle grinding equipment and method, used for automatic grinding of the outer circle of the weld after friction welding of the drill pipe body and the joint. Background Technology

[0002] Oil drill pipes are formed by friction welding of the pipe body and joints. After welding and heat treatment, the weld area will have excess weld weight and flash. According to industry standards SY / T5561-2008 "Friction Welded Drill Pipes" and API SPECIFICATION 5DP "Drill Pipe Specifications," the surface roughness of the outer diameter of the weld area should reach Ra 3.2 μm, and the outer diameter of the weld area should be within the allowable tolerance range to meet the requirements of subsequent fluorescent magnetic particle testing and ultrasonic testing. Therefore, grinding the outer diameter of the drill pipe weld is an indispensable and critical process on the drill pipe production line.

[0003] Currently, domestic drill pipe manufacturers generally have the following problems in grinding the outer diameter of weld seams: First, many manufacturers still use angle grinders with angle grinding discs for manual grinding, which is extremely inefficient, labor-intensive, requires a large work area, and causes serious noise and dust pollution. Moreover, the roundness of the surface after grinding is poor, and it needs to be polished in the subsequent process to barely meet the standards, which increases the workload of the polishing process and the consumption of polishing tape.

[0004] Secondly, although some manufacturers have introduced mechanical grinding machines, the grinding feed rate still relies on manual operation, and the depth of cut cannot be quantitatively controlled. In order to meet the deadline, employees often increase the depth of cut, resulting in the surface roughness failing to meet the requirement of Ra3.2μm, and even quality accidents such as the outer diameter being ground too small.

[0005] Third, the lateral reciprocating motion of existing mechanical grinding machines relies on manual force applied by both hands to push the four-wheeled trolley to move on the track. When the pressure on the handle is too high, the two wheels near the force application end are prone to tilting up or even derailing, causing a cutting accident that leads to the scrapping of the workpiece.

[0006] Fourth, the positioning of the weld seam relies on manual visual inspection, which has low positioning accuracy. When the weld seam position of different batches of drill rods is offset, it needs to be repeatedly adjusted, which seriously affects the consistency of grinding and production efficiency.

[0007] Fifth, existing equipment lacks online detection methods during the grinding process, and the grinding quality relies entirely on post-process inspection. It is impossible to detect problems such as dimensional deviations or substandard roughness in a timely manner during the grinding process, resulting in a high rework rate.

[0008] Sixth, existing grinding machines can usually only adapt to a single or a few specifications of drill rods, and the workload of adjusting the adaptability is large, making it difficult to efficiently cover eight specifications of drill rod products from Φ60.3 to Φ168.

[0009] Therefore, there is an urgent need for a grinding equipment and method for the outer diameter of drill pipe welds that can automatically identify weld positions, quantitatively control grinding feed, detect grinding quality in real time, adapt to various drill pipe specifications, and significantly reduce labor intensity. Summary of the Invention

[0010] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a grinding equipment and method for the outer circle of drill pipe welds. This equipment and method can automatically identify the weld position and reinforcement height, quantitatively control the grinding feed, detect the grinding quality in real time, realize the automatic switching between rough grinding and fine grinding in stages, and adapt to various specifications of drill pipes, thereby significantly improving grinding efficiency and quality consistency, and reducing labor intensity and rework rate.

[0011] A grinding device for the outer diameter of drill pipe welds includes a bed base 1, a guide rail 2, a slide table 3, a drill pipe rotation drive mechanism, an adaptive floating grinding head mechanism, an automatic weld identification and positioning device, a grinding feed control mechanism, an online detection device, a programmable control system 16, and a chip removal and dust removal device; wherein: The bed base 1 is an integral cast iron structure, with a guide rail 2 extending along the drill rod axis on top. A slide 3 that can reciprocate along the drill rod axis is supported on the guide rail 2. The slide 3 is driven by the reciprocating drive mechanism 21 to reciprocate along the guide rail 2. The drill rod rotation drive mechanism includes an active roller support mechanism 6 and a driven roller support mechanism 7. The two sets of roller support mechanisms are respectively set below both ends of the drill rod 4. The active roller support mechanism 6 is equipped with a drive motor and a reducer to drive the rollers 25 to rotate the drill rod 4. The spacing of the rollers 25 is adjustable to accommodate drill rods of different specifications from Φ60.3 to Φ168. The height of the roller support frame 24 is adjusted by the lifting cylinder 26 to match the relative position of drill rods of different diameters and grinding wheels. The adaptive floating grinding head mechanism includes a rocker arm 8, a hinge support 9, a constant force cylinder 10, a coarse grinding wheel 11, a fine grinding wheel 12, and a grinding motor 13. The middle part of the rocker arm 8 is hinged to the slide table 3 through the hinge support 9. The coarse grinding wheel 11 and the fine grinding wheel 12 are installed at the front end of the rocker arm 8, and the grinding motor 13 drives the coarse grinding wheel 11 and the fine grinding wheel 12 to rotate. The rear of the rocker arm 8 is hinged to the piston rod end of the constant force cylinder 10. The constant force cylinder 10 provides a constant and adjustable grinding pressure to maintain a stable contact force between the grinding wheel and the weld surface. The rocker arm 8 is allowed to float with a displacement of ±2mm in the radial direction, so that the grinding head can adapt to the irregular changes in the weld contour. The automatic weld identification and positioning device includes a displacement sensor 14 and a scanning moving frame 15. The scanning moving frame 15 moves along the axial direction of the drill rod 4. The displacement sensor 14 is installed on the scanning moving frame 15 and scans the outer circle contour point by point along the axial direction of the drill rod. It collects the diameter data of the reference outer circle area and the weld area. By comparing the difference between the reference outer circle diameter and the weld area diameter, it automatically identifies the start position, end position and residual height of the weld 5 and transmits the identification result to the programmable control system 16. The grinding feed control mechanism includes a lead screw feed mechanism 22 and a feed servo motor 23; the feed servo motor 23 drives the lead screw feed mechanism 22 to control the radial feed amount of the grinding head. The feed amount is automatically calculated and set according to the residual height measured by the weld identification device. During the grinding process, the feed amount can be finely adjusted in real time according to the online detection results. The online detection device includes a surface roughness detection probe 17 and an outer diameter measuring sensor 18. The roughness detection probe 17 is set next to the grinding area to detect the surface roughness value after grinding in real time. The diameter measuring sensor 18 is set in the diametrical direction of the drill rod to measure the change in the outer diameter after grinding in real time. The detection results of the two detection devices are transmitted to the programmable control system 16 in real time. The programmable control system 16 is a central control unit that stores grinding process parameters for drill pipes of different specifications, receives weld identification data and online detection data, coordinates the action sequence of each mechanism, realizes automatic setting and real-time adjustment of grinding parameters, and forms a closed-loop control from weld identification, parameter setting, staged grinding, online detection and parameter feedback adjustment. The dust removal device includes a dust collection hood 19 and a cleaning brush roller 20. The dust collection hood 19 partially surrounds the grinding area and is connected to a negative pressure dust collection pipe to collect grinding dust. The cleaning brush roller 20 is set next to the coarse grinding wheel 11 and rotates synchronously with the coarse grinding wheel 11 during the grinding process to clean the grinding debris adhering to the surface of the grinding wheel in real time and maintain the grinding ability of the grinding wheel.

[0012] S1. Drill rod clamping and positioning: Place the drill rod 4 on the rollers 25 of the active roller mechanism 6 and the driven roller mechanism 7. Adjust the spacing of the rollers 25 and the height of the roller frame 24 according to the specifications of the drill rod. Start the drive motor to make the drill rod 4 rotate at low speed and confirm that the relative position of the drill rod 4 and the grinding wheel is correct. S2. Automatic weld seam identification and scanning: The scanning moving frame 15 is started to move along the axis of the drill rod 4. The displacement sensor 14 scans the outer circle contour of the drill rod point by point, and collects the diameter data of the reference outer circle area and the weld seam area. The programmable control system 16 automatically identifies the starting position, ending position and residual height of the weld seam 5 through the data processing algorithm. S3. Automatic calculation and setting of grinding parameters: The programmable control system 16 automatically calculates the feed amount, grinding pressure, reciprocating speed and rough grinding target size in the rough grinding stage, as well as the feed amount, grinding pressure, reciprocating speed and fine grinding target size in the fine grinding stage, based on the weld identification data. At the same time, it calculates the reciprocating stroke range of the reciprocating drive mechanism 21 based on the start and end positions of the weld 5, and sends the calculation results to each actuator. S4. Rough Grinding Stage: Start the rotation and reciprocating drive mechanism 21 of drill rod 4, and the constant force cylinder 10 presses the rough grinding wheel 11 against the weld surface with a large pressure. The feed servo motor 23 controls the radial feed according to the calculated rough grinding feed amount, and the rough grinding wheel 11 quickly removes the weld excess height. S4a. Intermediate inspection during rough grinding: After the rough grinding stage is completed, the diameter distance sensor 18 measures the residual amount of the outer circle of the weld after rough grinding. The programmable control system 16 determines whether the residual amount is within the fine grinding allowance range of 0.3 to 0.5 mm. If the residual amount is too large, return to step S4 to supplement rough grinding. If it is within the allowance range, proceed to step S5. If the residual amount is too small (over-grinding) the alarm is issued to prompt the operator to handle it. S5, Fine Grinding Stage: The programmable control system 16 automatically switches to fine grinding parameters, the constant force cylinder 10 reduces the grinding pressure, the feed servo motor 23 controls the radial feed according to the fine grinding feed amount, and the fine grinding wheel 12 finely grinds to the target size and target roughness with a small feed amount. S6. Fine grinding online detection: During the fine grinding process, the roughness detection probe 17 detects the roughness value of the grinding surface in real time, the diameter distance sensor 18 measures the outer diameter of the grinding surface in real time, and the detection results are transmitted to the programmable control system 16 in real time. S7. Detection result judgment: The programmable control system 16 compares the online detection result with the target parameters. If the roughness reaches Ra3.2μm and the outer diameter is within the tolerance range, the grinding is judged to be up to standard and proceeds to step S8. If it is not up to standard, the programmable control system 16 automatically adjusts the fine grinding parameters according to the deviation direction and magnitude, and returns to step S5 for supplementary fine grinding. S8. Grinding complete: The programmable control system 16 sends a grinding complete signal, stops the drill rod rotation and the grinding head movement, and the constant force cylinder 10 releases pressure to lift the grinding head and generate a grinding quality report. S9. Unloading: Remove the polished drill rod 4 from the roller mechanism and begin the polishing cycle for the next drill rod.

[0013] 1. The automatic weld identification and positioning device enables automatic identification of weld position and reinforcement height, eliminating the error of manual visual positioning, solving the problem of frequent adjustments caused by weld position offset between different batches of drill pipes, and improving positioning accuracy and production efficiency.

[0014] 2. Through the adaptive floating grinding head mechanism, the constant force cylinder provides stable grinding pressure, and the radial floating design of the rocker arm enables the grinding head to adapt to the irregular changes in the weld contour, avoiding surface quality fluctuations and tool rolling accidents caused by sudden changes in grinding pressure, and ensuring the consistency of grinding quality.

[0015] 3. By adopting a staged grinding strategy of coarse grinding and fine grinding, the coarse grinding stage uses a large feed rate and pressure to quickly remove excess surface roughness and improve efficiency, while the fine grinding stage uses a small feed rate and pressure to ensure surface roughness and dimensional accuracy. This approach balances grinding efficiency and quality requirements and can directly achieve a roughness standard of Ra3.2μm, eliminating the need for subsequent polishing processes.

[0016] 4. Through a dual detection mechanism of intermediate detection during rough grinding and online detection during fine grinding, the residual material is detected immediately after rough grinding to prevent over-grinding. During fine grinding, the roughness and diameter are monitored in real time, and the detection results are fed back to the control system in real time to automatically adjust the grinding parameters, forming a complete closed-loop control, which significantly reduces the rework rate and over-grinding accidents.

[0017] 5. With an adjustable roller support mechanism and a liftable roller support frame, one set of equipment can cover eight specifications of drill pipe from Φ60.3 to Φ168, making adjustments convenient and quick, and reducing equipment configuration costs.

[0018] 6. The cleaning brush roller cleans debris from the surface of the grinding wheel in real time, maintaining the grinding wheel's grinding ability, extending its service life, and reducing the frequency of grinding wheel replacement and downtime.

[0019] 7. The overall level of automation is high, which greatly reduces the labor intensity and physical exertion of employees, improves the working environment, and eliminates the quality instability caused by manual operation. Attached Figure Description

[0020] Figure 1 This is a main view of the overall structure of the equipment of the present invention, showing the overall layout of the bed base 1, guide rail 2, slide table 3, drill rod rotation drive mechanism (active support roller mechanism 6, driven support roller mechanism 7), adaptive floating grinding head mechanism (rocker arm 8, hinge support 9, constant force cylinder 10, coarse grinding wheel 11, fine grinding wheel 12, grinding motor 13), weld automatic identification and positioning device (displacement sensor 14, scanning moving frame 15), online detection device (roughness detection probe 17, diameter distance sensor 18), and chip removal and dust removal device (dust collection hood 19, cleaning brush roller 20). The drill rod 4 is supported by two sets of support roller mechanisms, and the weld 5 is located in the middle of the drill rod.

[0021] Figure 2 This is a top view of the overall structure of the device of the present invention, showing the spatial relationship of each mechanism from a top perspective, including the roller support frame 24, the roller 25, the lifting cylinder 26, and the cooperation relationship between the drill rod 4 and the roller support mechanism.

[0022] Figure 3 This is a partial enlarged view of the adaptive floating grinding head mechanism of the present invention, which shows in detail the structure and connection relationship of the rocker arm 8, hinge support 9, constant force cylinder 10, coarse grinding wheel 11, fine grinding wheel 12, grinding motor 13, lead screw feed mechanism 22, feed servo motor 23 and cleaning brush roller 20, as well as a schematic diagram of the radial floating direction of the rocker arm 8.

[0023] Figure 4 This is a schematic diagram of the automatic weld identification and positioning device of the present invention, showing the installation method of the displacement sensor 14 on the scanning moving frame 15, the working principle of scanning along the axial direction of the drill rod 4, and the identification process of the starting position, ending position and residual height of the weld 5. The identification data of the displacement sensor 14 is transmitted to the programmable control system 16.

[0024] Figure 5 This is a schematic diagram of the installation position of the online detection device of the present invention. The roughness detection probe 17 and the outer diameter measuring sensor 18 are shown from the perspective of the drill rod 4 cross section, relative to the drill rod 4 and the grinding wheels (coarse grinding wheel 11 and fine grinding wheel 12). The diameter measuring sensor 18 adopts a dual-sensor diameter measurement method, and the detection results are fed back to the programmable control system 16 to form a closed-loop control relationship. The positions of the dust collection hood 19 and the cleaning brush roller 20 are also shown.

[0025] Figure 6 This is a flowchart of the grinding method of the present invention, showing the complete grinding method steps from step S1 (drill rod clamping and positioning) to step S9 (material unloading), including step S2 (weld identification), step S3 (parameter setting), step S4 (rough grinding), step S4a (intermediate detection of rough grinding), step S5 (fine grinding), step S6 (online detection of fine grinding), step S7 (determination of detection results), and a closed-loop feedback adjustment process that returns to step S5 when the standard is not met. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Reference Figure 1 and Figure 2 The present invention provides a grinding device for the outer diameter of a drill pipe weld, comprising a bed base 1, a guide rail 2, a slide table 3, a drill pipe rotation drive mechanism, an adaptive floating grinding head mechanism, an automatic weld identification and positioning device, a grinding feed control mechanism, an online detection device, a programmable control system 16, and a chip removal and dust removal device.

[0028] The bed base 1 is an integral cast iron structure with sufficient rigidity and stability. Two parallel guide rails 2 extending along the drill rod axis are mounted on top. The guide rails 2 employ a combination of V-shaped and rectangular guide rails to ensure the movement accuracy of the slide table 3. The slide table 3 is supported on the guide rails 2 and is driven by a reciprocating drive mechanism 21 to reciprocate along the guide rails 2. The reciprocating drive mechanism 21 is a hydraulic cylinder. One end of the cylinder is fixedly connected to the bed base 1, and the other end is connected to the slide table 3. Adjustable reversing contacts are provided on both sides of the slide table 3, and corresponding contact switches are provided on the bed base 1. The reversing switches control the extension and retraction of the cylinder piston rod, driving the slide table 3 to reciprocate. The reciprocating stroke range is automatically calculated and determined by the programmable control system 16 in step S3 based on the start and end positions of the weld 5, typically covering a range of approximately 150 to 250 mm of the weld length. The reciprocating speed can be controlled by a hydraulic flow regulating valve, typically set to 0.5 to 1.5 m / min.

[0029] The drill pipe rotation drive mechanism includes an active roller support mechanism 6 and a driven roller support mechanism 7. The two sets of roller support mechanisms are respectively located below both ends of the drill pipe 4, arranged along the drill pipe axis. The active roller support mechanism 6 includes a base, a roller support frame 24, four guide columns, two lifting cylinders 26, a pair of rollers 25, and a power drive device. The base is a four-legged support structure, fixed to the ground via flanges. The guide columns and lifting cylinders 26 connect to the roller support frame 24. The lifting cylinders 26 drive the roller support frame 24 to rise and fall along the guide columns. The height of the roller support frame 24 is adjusted according to the different diameters of the drill pipe to match the relative position of the drill pipe 4 and the grinding wheel. After reaching the correct position, equal-height blocks are placed under the roller support frame 24 for support, ensuring the height of the rollers 25 is stable. The spacing of the rollers 25 is adjustable, and the installation position of the rollers can be adjusted to adapt to the support requirements of drill pipes 4 with different specifications from Φ60.3 to Φ168. The power drive unit includes a drive motor and a reducer, which is connected to one of the roller shafts in the rollers 25 via a sprocket and chain drive, driving the roller to rotate the drill rod 4. The rotation direction of the drill rod 4 is opposite to that of the grinding wheel, and the speed is controlled between 25 and 30 revolutions per minute. The driven roller support mechanism 7 has the same structure as the driving roller support mechanism 6, but it does not have a power drive unit and only serves as a driven support.

[0030] Reference Figure 3 The adaptive floating grinding head mechanism is one of the core innovations of this invention. The mechanism includes a rocker arm 8, a hinge support 9, a constant force cylinder 10, a coarse grinding wheel 11, a fine grinding wheel 12, a grinding motor 13, a lead screw feed mechanism 22, and a feed servo motor 23.

[0031] The rocker arm 8 is a rigid arm structure, hinged to the slide table 3 in the middle via a hinge support 9. The hinge support 9 uses a hinge shaft structure, allowing the rocker arm 8 to rotate around the hinge support 9 in a vertical plane, realizing the up-and-down swing of the grinding head. A coarse grinding wheel 11 and a fine grinding wheel 12 are mounted at the front end of the rocker arm 8. The coarse grinding wheel 11 uses brown corundum abrasive, with a size of 30×Φ350mm. Approximately one-third of it is exposed for grinding, while the remaining part is covered by a protective cover, used for quickly removing weld excess. The fine grinding wheel 12 uses white corundum or chromium corundum abrasive, with a size of 20×Φ250mm, and a finer grit, used for fine grinding to ensure surface roughness. The coarse grinding wheel 11 and the fine grinding wheel 12 are mounted side-by-side at the front end of the rocker arm 8 and are driven to rotate by the grinding motor 13 via belt drive. The grinding motor 13 is mounted above and behind the rocker arm 8. Its output shaft is connected to the grinding wheel shaft of the coarse grinding wheel 11 via a pulley and belt. The grinding wheel shaft of the coarse grinding wheel 11 is linked to the grinding wheel shaft of the fine grinding wheel 12 via a coaxial pulley or transmission gear, so as to realize the synchronous rotation of the two grinding wheels. Alternatively, two independent grinding motors can be used to drive the coarse grinding wheel 11 and the fine grinding wheel 12 respectively to achieve independent control of different speeds.

[0032] The rear of the rocker arm 8 is hinged to the piston rod end of the constant force cylinder 10. The constant force cylinder 10 uses a proportional pressure control valve to provide a constant and adjustable grinding pressure. During the rough grinding stage, the constant force cylinder 10 applies a relatively high pressure (typically 0.5 to 0.8 MPa) to press the rough grinding wheel 11 tightly against the weld surface, ensuring rapid removal of excess weld material. During the fine grinding stage, the constant force cylinder 10 automatically reduces the pressure to 0.2 to 0.4 MPa, allowing the fine grinding wheel 12 to contact the weld surface with a light pressure, ensuring surface roughness. The constant force cylinder 10 is mounted on a cantilever plate behind the column, with the cylinder rod extension hinged to the rear of the rocker arm 8, and the fixed end of the cylinder body connected to the slide table 3.

[0033] The rocker arm 8 is allowed to float by ±2mm in the radial direction (perpendicular to the axis of drill rod 4 and the axis of grinding wheel). This floating function is achieved through the hinge shaft clearance of the hinge support 9 and the elastic connection of the constant force cylinder 10, so that when there are irregular bumps and concave changes in the contour of weld 5, the grinding head can float slightly to adapt, avoiding local over-grinding or under-grinding, and ensuring the consistency of grinding quality throughout the entire circle.

[0034] The lead screw feed mechanism 22 is mounted on the slide table 3 and driven by the feed servo motor 23 to control the radial feed of the grinding head. The end of the lead screw of the lead screw feed mechanism 22 presses against the positioning plate with a spherical recess in front of the rocker arm 8, and rotating the lead screw realizes the radial feed of the grinding wheel during grinding. The feed amount is automatically calculated by the programmable control system 16 based on the weld identification data: the total feed amount in the rough grinding stage is equal to the weld height minus the fine grinding allowance of 0.3 to 0.5 mm; the feed amount in the fine grinding stage is equal to the remaining allowance after rough grinding. The stepping accuracy of the feed servo motor 23 is 0.01 mm, ensuring precise control of the feed amount.

[0035] Reference Figure 4 The automatic weld seam identification and positioning device is another core innovation of this invention. This device includes a displacement sensor 14 and a scanning moving frame 15. The scanning moving frame 15 is a portal frame structure, straddling the drill rod 4, and can move along the axial direction of the drill rod 4. The displacement sensor 14 is mounted on the scanning moving frame 15, with the measurement direction facing the outer surface of the drill rod 4. The scanning moving frame 15 is driven by a servo motor to achieve precise movement along the guide rail, with a movement accuracy of ±0.5mm and an adjustable movement speed range of 50 to 100mm / s.

[0036] The working process is as follows: Before grinding, the scanning moving frame 15 moves at a constant speed along the axial direction from one end of the drill rod 4. The displacement sensor 14 collects displacement data of the outer surface of the drill rod 4 point by point, with a sampling interval of 1 to 2 mm. The scanning range covers an area of ​​50 mm before and after the weld. In the reference outer circle area (the normal outer circle of the pipe before and after the weld), the diameter data measured by the displacement sensor 14 fluctuates little, representing the reference outer circle size of the pipe body. When the scan enters the weld 5 area, the outer circle diameter increases due to the weld reinforcement, and the displacement data measured by the displacement sensor 14 shows a significant jump. The programmable control system 16 analyzes and processes the collected data. By setting a threshold comparison algorithm, the area where the difference between the displacement data and the reference outer circle data exceeds the set threshold (usually above 0.1 mm) is determined as the weld area, thereby automatically determining the start and end positions of the weld 5. The maximum displacement difference in the weld area is the weld reinforcement height, which serves as the basis for calculating the grinding feed.

[0037] The programmable control system 16 also verifies the rationality of the identification results: it checks whether the excess height is within the normal range of 0.5 to 3.0 mm and whether the weld length is within the normal range of 50 to 300 mm. If the identification results exceed the normal range, the data is judged to be abnormal and an alarm is issued to prompt the operator to confirm, so as to avoid incorrect weld identification results and grinding parameter calculations caused by interference factors such as oil stains and rust on the drill pipe surface.

[0038] This device eliminates the error of manual visual positioning, solves the problem of frequent adjustments caused by the offset of weld seam positions in different batches of drill rods, and makes the grinding positioning accuracy within ±1mm.

[0039] Reference Figure 5 The online detection device includes a surface roughness detection probe 17 and an outer diameter ranging sensor 18, which are key components of the closed-loop control of this invention.

[0040] The surface roughness detection probe 17 is installed beside the grinding area, behind the fine grinding wheel 12, with the probe's measurement direction pointing towards the newly ground outer cylindrical surface of the drill rod 4. This probe employs a fiber optic online surface roughness detection principle, calculating the surface roughness Ra value by analyzing the spectral characteristics of reflected light. This principle is a known fiber optic online surface roughness detection technology in the grinding field, and mature commercial products are available (such as the online surface roughness detector manufactured by Keyence), achieving a detection accuracy of ±0.2μm, meeting the detection requirement of Ra 3.2μm. The measurement distance between the probe and the surface of the drill rod 4 is maintained within the range of 2 to 5 mm to avoid collision with the rotating drill rod 4.

[0041] The outer diameter distance sensor 18 is positioned along the diameter direction of the drill rod 4, employing a dual-sensor diameter measurement method: one sensor is located above the drill rod 4 to measure the distance to the upper surface, and the other is located below the drill rod 4 to measure the distance to the lower surface. The sum of the two distances is the outer diameter of the drill rod 4. This measurement method is unaffected by the rotational eccentricity of the drill rod 4, achieving a diameter measurement accuracy of ±0.02mm. This sensor also utilizes the laser distance measurement principle, a known and mature commercial technology.

[0042] The test results from the two testing devices are transmitted in real time to the programmable control system 16 via signal lines. The programmable control system 16 compares the measured roughness with the target value Ra3.2μm, and compares the measured diameter with the target diameter and tolerance range to form a closed-loop judgment. If the test results meet the standards, a grinding completion signal is issued; if they do not meet the standards, the adjustment amount is automatically calculated based on the deviation direction and magnitude, and the feed amount of the feed servo motor 23, the grinding pressure of the constant force cylinder 10, or the reciprocating speed of the reciprocating drive mechanism 21 are adjusted to perform supplementary grinding until the standards are met.

[0043] The closed-loop control mechanism of this invention consists of two levels: the first level is a rough grinding intermediate detection closed loop (step S4a). After rough grinding, the diameter measuring sensor 18 detects the residual material. If the residual material is too large, it returns to step S4 to supplement rough grinding; if it is within the fine grinding allowance range of 0.3 to 0.5 mm, it enters fine grinding; if it is too small, an alarm is triggered to prevent irreversible damage caused by over-grinding. The second level is a fine grinding online detection closed loop (steps S6 and S7). During fine grinding, roughness and diameter are monitored simultaneously. If the target is not met, the fine grinding parameters are automatically adjusted, and it returns to step S5 to supplement fine grinding. The two levels form a complete dual closed-loop control, ensuring that rough grinding is not overdone and fine grinding meets the target.

[0044] The programmable control system 16 serves as the central control unit, implemented using a programmable logic controller (PLC) or an industrial computer, and is installed within the control cabinet. This system stores a database of grinding process parameters for different specifications of drill rods 4, including parameters such as roughing feed rate, fine grinding feed rate, grinding pressure, reciprocating speed, target roughness, target diameter, and tolerance range for eight drill rod specifications ranging from Φ60.3 to Φ168. Operators only need to select the drill rod specification number currently being processed on the control panel, and the programmable control system 16 will automatically retrieve the corresponding process parameters, calculate the specific feed rate and reciprocating stroke range based on weld seam identification data, achieving one-button fully automatic grinding. The programmable control system 16 is also responsible for coordinating the action sequence of various mechanisms, including the order and linkage of steps such as drill rod rotation start-up, scanning identification, grinding head feed, reciprocating motion, roughing intermediate detection, fine grinding online detection, parameter adjustment, and grinding completion.

[0045] The dust removal device includes a dust collection hood 19 and a cleaning brush roller 20. The dust collection hood 19 has a semi-enclosed structure, covering the grinding area above and to the side, with an opening at the bottom for the drill rod 4 to pass through. The dust collection hood 19 is connected to a negative pressure dust collection pipe via a flange, and the other end of the pipe is connected to the central dust removal system in the workshop. During the grinding process, a negative pressure is continuously generated to suck away grinding dust, improving the working environment. The cleaning brush roller 20 is located beside the coarse grinding wheel 11 and is linked to the rotating shaft of the coarse grinding wheel 11 via a transmission gear. When the coarse grinding wheel 11 rotates for grinding, the cleaning brush roller 20 rotates synchronously, and its outer bristles contact the grinding surface of the coarse grinding wheel 11, cleaning the metal chips and abrasive residue adhering to the surface of the grinding wheel in real time, maintaining the grinding ability of the grinding wheel and extending its service life.

[0046] The polishing method of this invention refers to Figure 6 The flowchart and specific implementation steps are as follows: Step S1: Drill Rod Clamping and Positioning. Place the drill rod 4 on the rollers 25 of the active roller support mechanism 6 and the driven roller support mechanism 7. The operator selects the drill rod specification number (e.g., Φ127) on the operation panel of the programmable control system 16, and the programmable control system 16 automatically calls up the corresponding process parameters. The lifting cylinder 26 lifts the roller support frame 24 to the height position corresponding to the specification, and after placing equal-height blocks under the roller support frame 24 for support, the cylinder is closed. Adjust the spacing of the rollers 25 to adapt to the outer diameter of the drill rod. Start the drive motor to rotate the drill rod 4 at a low speed (25 to 30 rpm), and confirm that the drill rod 4 rotates smoothly and its relative position with the grinding wheel is correct.

[0047] Step S2: Automatic Weld Identification Scan. The scanning motion frame 15 is started and moves uniformly along the axis of the drill rod 4 at a speed of 50 to 100 mm / s. The displacement sensor 14 collects displacement data point by point on the outer surface of the drill rod 4, with a sampling interval of 1 to 2 mm. The scanning range covers an area 50 mm before and after the weld. The programmable control system 16 analyzes the collected data, identifying areas where the displacement difference exceeds the 0.1 mm threshold as weld areas, and automatically determines the start position, end position, and residual height of the weld 5. Simultaneously, the programmable control system 16 verifies the rationality of the identification results, checking whether the residual height is within the range of 0.5 to 3.0 mm and whether the weld length is within the range of 50 to 300 mm; if these ranges are exceeded, an alarm is triggered. For example, the identification result is: the weld start position is 4520 mm from the drill rod end face, the end position is 4720 mm from the end face, and the residual height is 1.8 mm.

[0048] Step S3: Automatic calculation and setting of grinding parameters. The programmable control system 16 automatically calculates the grinding parameters based on the weld identification data. Rough grinding stage: Total feed = remaining height 1.8mm - fine grinding allowance 0.4mm = 1.4mm, grinding pressure 0.6MPa, reciprocating speed 1.0m / min, rough grinding target size is 0.4mm from the final size. Fine grinding stage: Feed 0.4mm, grinding pressure 0.3MPa, reciprocating speed 0.6m / min, fine grinding target size is the final size, target roughness Ra 3.2μm. Simultaneously, the programmable control system 16 calculates the reciprocating stroke range from 4510mm to 4730mm from the drill rod end face (extending 10mm forward and backward) based on the starting position 4520mm and ending position 4720mm of weld 5, and sends the reciprocating stroke range parameters to the reciprocating drive mechanism 21. All calculation results are sent to the feed servo motor 23, the constant force cylinder 10, and the reciprocating drive mechanism 21.

[0049] Step S4: Rough Grinding Stage. The programmable control system 16 issues a rough grinding start command. The reciprocating drive mechanism 21 drives the slide table 3 to reciprocate along the guide rail 2 within the full length of the weld seam according to the calculated reciprocating stroke range. The constant force cylinder 10 presses the rough grinding wheel 11 against the weld seam surface with a pressure of 0.6 MPa. The feed servo motor 23 controls the radial feed in multiple steps (each step 0.05 to 0.1 mm) according to a total feed amount of 1.4 mm. The drill rod 4 rotates in the opposite direction to the rough grinding wheel 11 at a speed of 25 to 30 rpm. The rough grinding wheel 11 quickly removes the excess weld seam height. During the rough grinding process, the cleaning brush roller 20 rotates synchronously to clean the debris on the surface of the grinding wheel.

[0050] Step S4a: Intermediate detection during rough grinding. After the cumulative feed amount during the rough grinding stage reaches the calculated value, the programmable control system 16 issues a rough grinding pause command, temporarily stopping the grinding head feed and reciprocating motion (drill rod 4 continues to rotate at low speed). The diameter distance sensor 18 measures the residual material on the outer circle of weld 5 after rough grinding. The programmable control system 16 determines whether the residual material is within the fine grinding allowance range of 0.3 to 0.5 mm: if the residual material is too large (exceeding 0.5 mm), the supplementary rough grinding feed amount is recalculated (supplementary feed amount = residual material - 0.4 mm), and the process returns to step S4 for supplementary rough grinding; if the residual material is within the range of 0.3 to 0.5 mm, the process proceeds to step S5 for fine grinding; if the residual material is too small (less than 0.3 mm, indicating over-grinding), an alarm is issued to prompt the operator to handle the situation and avoid irreversible damage.

[0051] Step S5: Fine grinding stage. The programmable control system 16 automatically switches to fine grinding parameters, the pressure of the constant force cylinder 10 is reduced to 0.3MPa, the feed servo motor 23 controls the radial feed in multiple micro-steps according to the fine grinding feed amount (each step is 0.01 to 0.02mm), the reciprocating speed is reduced to 0.6m / min, and the fine grinding wheel 12 finely grinds the weld surface with a small feed amount and light pressure.

[0052] Step S6: Online fine grinding inspection. During the fine grinding process, the roughness detection probe 17 detects the surface roughness Ra value of the freshly ground surface in real time, and the diameter distance sensor 18 measures the outer diameter of the ground surface in real time. The detection results are sampled every 0.5 seconds and transmitted to the programmable control system 16 in real time.

[0053] Step S7: Result Determination. The programmable control system 16 compares the measured roughness with the target value Ra3.2μm, and compares the measured diameter with the target diameter and tolerance range. If the roughness is ≤Ra3.2μm and the diameter is within the tolerance range, the grinding is deemed satisfactory, and the process proceeds to step S8. If the roughness does not meet the standard, the programmable control system 16 automatically increases the fine grinding feed by 0.01 to 0.05mm based on the deviation and returns to step S5 to continue fine grinding; if the diameter is too large (residue not completely removed), the process returns to step S5 for supplementary fine grinding; if the diameter is too small (over-grinding), an alarm is issued to prompt the operator for handling.

[0054] Step S8: Grinding complete. The programmable control system 16 sends a grinding complete signal, stopping the rotation of the drill rod 4 and the movement of the grinding head. The constant force cylinder 10 releases pressure, causing the grinding head to lift and detach from the weld surface. The lead screw feed mechanism 22 returns to its initial position, and the reciprocating drive mechanism 21 stops its reciprocating motion. The programmable control system 16 automatically generates a grinding quality report, recording the drill rod's specification number, weld identification data, rough grinding parameters, intermediate rough grinding test results, fine grinding parameters, online fine grinding test results, and final judgment conclusion for quality traceability.

[0055] Step S9: Unloading. The operator removes the finished drill rod 4 from the roller support mechanism and places the next drill rod to be ground on the roller support mechanism, starting the grinding cycle for the next drill rod. Since the programmable control system 16 has stored the process parameters for the current specification, there is no need to reset the parameters when continuously grinding drill rods of the same specification. Grinding can be started automatically by simply executing the weld seam recognition scan in step S2, achieving efficient continuous production.

[0056] The technical solution of this invention forms a complete dual closed loop: the first closed loop is the rough grinding closed loop (steps S4→S4a), which prevents over-grinding during rough grinding through intermediate detection; the second closed loop is the fine grinding closed loop (steps S5→S6→S7), which ensures that the surface roughness and outer diameter meet the standards through online fine grinding detection. From automatic weld identification (inputting identification data) to automatic setting of grinding parameters (parameter calculation) to staged grinding (rough grinding + fine grinding execution) to online detection (process monitoring) to detection result judgment and parameter feedback adjustment (closed loop correction), each link is interconnected and data is shared, ensuring that the grinding quality of each drill rod is stable and meets the standards, eliminating the uncertainties caused by manual operation.

Claims

1. A grinding device for the outer diameter of drill pipe welds, comprising a bed base, a drill pipe rotation drive mechanism, a grinding head mechanism, a weld identification device, a grinding feed control mechanism, an online detection device, and a control system, characterized in that: The bed base 1 is provided with a guide rail 2 extending along the drill rod axis. The guide rail 2 supports a slide 3 that can reciprocate along the drill rod axis. The slide 3 is driven by a reciprocating drive mechanism 21. The drill rod rotation drive mechanism includes an active roller mechanism 6 and a driven roller mechanism 7. The two sets of roller mechanisms are respectively located below both ends of the drill rod 4. The active roller mechanism 6 is equipped with a drive motor and a reducer to drive the rollers 25 to rotate the drill rod 4. The spacing of the rollers 25 is adjustable to accommodate different specifications of drill rods. The height of the roller frame 24 is adjusted by the lifting cylinder 26. The grinding head mechanism is an adaptive floating grinding head mechanism, including a rocker arm 8, a hinge support 9, a constant force cylinder 10, a coarse grinding wheel 11, a fine grinding wheel 12, and a grinding motor 13; the middle part of the rocker arm 8 is hinged to the slide table 3 through the hinge support 9, the front end of the rocker arm 8 is equipped with the coarse grinding wheel 11 and the fine grinding wheel 12, the grinding motor 13 drives the coarse grinding wheel 11 and the fine grinding wheel 12 to rotate, the rear of the rocker arm 8 is hinged to the piston rod end of the constant force cylinder 10, the constant force cylinder 10 provides a constant and adjustable grinding pressure, and the rocker arm 8 is allowed to float in the radial direction to adapt to the changes in the weld contour; The weld identification device includes a displacement sensor 14 and a scanning moving frame 15. The scanning moving frame 15 moves along the drill rod axis, and the displacement sensor 14 scans the outer circle contour of the drill rod point by point. By comparing the diameter difference between the reference outer circle and the weld area, the starting position, ending position and residual height of the weld 5 are automatically identified. The grinding feed control mechanism includes a lead screw feed mechanism 22 and a feed servo motor 23. The feed servo motor 23 drives the lead screw feed mechanism 22 to control the radial feed of the grinding head. The feed amount is automatically calculated based on the weld identification data. The online detection device includes a surface roughness detection probe 17 and an outer diameter measuring sensor 18. The roughness detection probe 17 detects the surface roughness of the polished surface in real time, and the diameter measuring sensor 18 measures the outer diameter of the polished surface in real time. The detection results are transmitted to the control system in real time. The control system is a programmable control system 16, which receives weld identification data and online detection data, stores grinding process parameters for drill rods of different specifications, coordinates the timing of actions of each mechanism, realizes automatic setting and real-time adjustment of grinding parameters, and forms a closed-loop control.

2. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The constant force cylinder 10 adopts a proportional pressure control valve, which provides a grinding pressure of 0.5 to 0.8 MPa during the rough grinding stage and automatically switches to a grinding pressure of 0.2 to 0.4 MPa during the fine grinding stage.

3. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The radial displacement of the rocker arm 8 is ±2mm, which is achieved through the hinge shaft clearance of the hinge support 9 and the elastic connection of the constant force cylinder 10.

4. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The coarse grinding wheel 11 is a brown fused alumina abrasive wheel with a size of 30×Φ350mm; the fine grinding wheel 12 is a white fused alumina or chromium fused alumina abrasive wheel with a size of 20×Φ250mm, and the grit size is finer than that of the coarse grinding wheel.

5. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The displacement sensor 14 is a laser displacement sensor.

6. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The outer diameter measuring sensor 18 adopts a dual-sensor diameter measurement method, with one sensor located above the drill rod and the other located below the drill rod. The sum of the two distances is the outer diameter of the drill rod.

7. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: It also includes a dust removal device, which includes a dust collection hood 19 and a cleaning brush roller 20; the dust collection hood 19 partially surrounds the grinding area and is connected to a negative pressure dust suction pipe; the cleaning brush roller 20 is set next to the coarse grinding wheel 11 and rotates in conjunction with the coarse grinding wheel 11 through a transmission gear to clean the debris on the surface of the grinding wheel in real time.

8. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The reciprocating drive mechanism 21 is a hydraulic cylinder. One end of the cylinder is fixedly connected to the bed base 1, and the other end is connected to the slide 3. The slide 3 is provided with reversing contacts on both sides, and the bed base 1 is provided with a contact switch at the corresponding position. The reversing switch controls the cylinder to drive the slide 3 to achieve reciprocating movement.

9. The drill pipe weld outer diameter grinding equipment according to claim 1, characterized in that: The programmable control system 16 is a programmable logic controller.

10. A grinding device for the outer diameter of drill pipe welds according to claim 1, characterized in that: The stepping accuracy of the feed servo motor 23 is 0.01mm; the feed amount in the rough grinding stage is equal to the weld seam height minus 0.3 to 0.5mm of the fine grinding allowance, and the feed amount in the fine grinding stage is equal to the allowance remaining after rough grinding.

11. A method for grinding the outer diameter of a drill pipe weld using the equipment described in any one of claims 1 to 10, characterized in that... Includes the following steps: S1. Drill rod clamping and positioning: Place the drill rod 4 on the rollers 25 of the roller support mechanism, adjust the spacing of the rollers 25 and the height of the roller support frame 24 according to the specifications of the drill rod, and start the drive motor to make the drill rod 4 rotate at low speed. S2. Automatic weld seam identification and scanning: The scanning moving frame 15 moves along the axis of the drill rod 4, and the displacement sensor 14 scans the outer circle contour of the drill rod point by point. The control system automatically identifies the starting position, ending position and residual height of the weld seam 5 through the data processing algorithm. S3. Automatic calculation and setting of grinding parameters: The control system automatically calculates the rough grinding feed, rough grinding pressure, fine grinding feed, fine grinding pressure, reciprocating speed and reciprocating stroke range based on the weld identification data. S4. Rough grinding stage: The constant force cylinder 10 presses the rough grinding wheel 11 against the weld surface with a large pressure. The feed servo motor 23 controls the radial feed according to the calculated rough grinding feed amount. The rough grinding wheel 11 quickly removes the excess height of the weld. S4a. Intermediate detection during rough grinding: After the rough grinding stage is completed, the diameter distance sensor 18 measures the residual amount of the outer circle of the weld after rough grinding. The control system determines whether the residual amount is within the fine grinding allowance range of 0.3 to 0.5 mm. If the residual amount is too large, return to step S4 to supplement rough grinding. If it is within the allowance range, proceed to step S5. If it is too small, an alarm is triggered. S5, Fine Grinding Stage: The control system automatically switches to fine grinding parameters, the constant force cylinder 10 reduces the grinding pressure, the feed servo motor 23 controls the radial feed according to the fine grinding feed amount, and the fine grinding wheel 12 finely grinds to the target size and target roughness. S6. Fine grinding online inspection: Roughness detection probe 17 detects the roughness of the ground surface in real time, diameter distance sensor 18 measures the outer diameter of the ground circle in real time, and the detection results are transmitted to the control system in real time. S7. Detection result judgment: The control system compares the detection result with the target parameter. If the target is met, proceed to step S8. If the target is not met, automatically adjust the fine grinding parameters and return to step S5 for supplementary fine grinding. S8. Grinding complete: The control system sends a completion signal, stops the movement of each mechanism, and generates a grinding quality report; S9. Unloading: Remove the polished drill rod and begin the polishing cycle for the next drill rod.

12. The method for grinding the outer diameter of the drill pipe weld according to claim 11, characterized in that: In step S4, the radial feed increment for each rough grinding stage is 0.05 to 0.1 mm; in step S5, the radial feed increment for each fine grinding stage is 0.01 to 0.02 mm.

13. The method for grinding the outer diameter of the drill pipe weld according to claim 11, characterized in that: In step S7, if the surface roughness does not meet the standard, the control system automatically increases the fine grinding feed by 0.01 to 0.05 mm according to the deviation range and returns to step S5; if the outer diameter is too large, it returns to step S5 to supplement the fine grinding; if the outer diameter is too small, it issues an alarm.

14. The method for grinding the outer diameter of the drill pipe weld according to claim 11, characterized in that: In step S2, the sampling interval of the displacement sensor 14 is 1 to 2 mm, the scanning speed is 50 to 100 mm / s, and the scanning range covers an area of ​​50 mm before and after the weld.

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