Long pipe cutting method

Abstract

The invention is suitable for the field of laser pipe cutting, and discloses a long pipe cutting method which comprises the following steps: conveying a pipe through a conveying chain, and moving a chuck structure close to the conveying chain to the end part of the pipe along a sliding rail to realize pre-positioning when the linear deviation rate is detected to be greater than a linear deviation rate threshold value; thirdly, the clamping pressure of the multiple chuck structures is synchronously adjusted based on the pipe diameter value of the pipe so that the clamping pressure of each chuck structure can be kept within a preset clamping pressure range value, and when the coaxiality error is larger than a coaxiality error threshold value, the clamping pressure of the multiple chuck structures can be adjusted; the displacement amount of each chuck structure is adjusted based on a cooperative compensation mechanism of the multiple chuck structures so that the coaxiality error of the multiple chuck structures can not be larger than a coaxiality error threshold value, finally, a laser cutting mechanism is started to cut the pipe, and when the radial run-out amount of the pipe is larger than a radial run-out amount threshold value, the laser cutting mechanism is started to cut the pipe. And when the vertical deformation quantity is larger than the vertical deformation quantity threshold value, the cutting height of the laser cutting mechanism is adjusted, and therefore the cutting precision can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser tube cutting, and in particular to a long tube cutting method. Background Art

[0002] In the fields of laser tube cutting and precision machining, efficient and accurate cutting of long tubes is a key technical difficulty in the manufacturing process. With the development of aerospace, rail transportation and high-end equipment manufacturing industries, higher requirements are placed on the cutting accuracy (such as coaxiality and cut perpendicularity) and production efficiency of long tubes. The following problems are common in traditional long tube cutting processes:

[0003] 1. Insufficient positioning accuracy of pipe transmission

[0004] Long pipes are prone to axis deviation during conveyor chain transport due to factors such as inherent deflection and conveyor speed fluctuations. Traditional mechanical limiters can only provide rough positioning. When the pipe axis deviates from the conveying direction by more than 0.5mm / m, the subsequent chuck clamping will significantly increase the coaxiality error (usually >0.2mm) due to inconsistent initial positioning, requiring repeated manual adjustments, seriously affecting processing efficiency.

[0005] 2. Clamping force control lacks adaptive ability

[0006] Existing chuck clamping systems mostly use a fixed pressure mode, which cannot dynamically adjust the clamping force according to the pipe diameter (20-200mm) and cross-sectional shape (such as round pipes, rectangular pipes). For example, when clamping thin-walled pipes (wall thickness ≤ 2mm), fixed pressure can easily cause the pipe to dent and deform; when clamping thick-walled pipes (wall thickness ≥ 5mm), insufficient pressure can cause the pipe to slip, and the success rate of a single clamping is only 75%-80%. At the same time, the contact area between the traditional rigid clamping surface and the pipe surface is less than 60%, and the friction coefficient is low (μ = 0.35). During the cutting process, even slight slippage of the pipe can result in a cut deviation of more than 0.3mm.

[0007] 3. Lack of multi-chuck collaborative compensation mechanism

[0008] In traditional three-chuck systems, the position of each chuck is adjusted independently, lacking real-time coordinated control. When the pipe is deflected due to its own weight (e.g., vertical deformation >1mm / m), the chuck coaxiality error may exceed 0.1mm. Manual calibration of each axis by adjusting the bolts takes >5 minutes per calibration, and the accuracy is difficult to stabilize within 0.05mm. In addition, the radial runout (>0.2mm) caused by thermal deformation or vibration of the pipe during the cutting process cannot be compensated in real time, resulting in fluctuations in the distance between the laser cutting head and the pipe surface and deterioration of the incision quality (such as burrs and slag).

[0009] The above problems easily lead to reduced cutting accuracy, so the existing technology needs to be improved and developed. Summary of the Invention

[0010] The object of the present invention is to provide a long pipe cutting method, which aims to solve the technical problem of low precision in existing pipe cutting.

[0011] To achieve the above object, the present invention provides the following solutions:

[0012] A long pipe cutting method, the long pipe cutting method is implemented based on a pipe cutting system, the pipe cutting system includes a conveyor chain, a side hanger, a laser cutting mechanism and a plurality of chuck structures, the conveyor chain and the side hanger are arranged along the conveying direction, the laser cutting mechanism is arranged on the side hanger, and the plurality of chuck structures are arranged on the side hanger at intervals along the conveying direction, the long pipe cutting method includes: in an initial state, the pipe is conveyed by the conveyor chain, and the linear deviation rate of the pipe axis and the conveying direction is monitored in real time, when it is detected that the linear deviation rate is greater than the linear deviation rate threshold, the chuck structure close to the conveyor chain is moved along the slide rail to the end of the pipe to achieve pre-positioning; after the pre-positioning is completed, the pipe diameter value of the pipe is obtained, and the clamping pressure of the plurality of chuck structures is synchronously adjusted based on the pipe diameter value so that the clamping pressure of each chuck structure Maintain within the preset clamping pressure range value; when the clamping pressure of each chuck structure is maintained within the preset clamping pressure range value, measure the coaxiality error of multiple chuck structures in real time, and when the coaxiality error is greater than the coaxiality error threshold, adjust the displacement of each chuck structure based on the coordinated compensation mechanism of multiple chuck structures so that the coaxiality error of multiple chuck structures is not greater than the coaxiality error threshold; when the coaxiality error of multiple chuck structures is not greater than the coaxiality error threshold, complete the pipe positioning, and start the laser cutting mechanism to cut the pipe. During the cutting operation, collect the radial runout and vertical deformation of the pipe. When the radial runout of the pipe is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, adjust the cutting height of the laser cutting mechanism based on the radial runout threshold and the vertical deformation.

[0013] Preferably, after the pre-positioning is completed, the diameter value of the pipe is obtained, and the clamping pressure of multiple chuck structures is synchronously adjusted based on the diameter value of the pipe so that the clamping pressure of the chuck structure is maintained within a preset clamping pressure range value, including: after the pre-positioning is completed, the diameter value of the pipe is obtained; the reference clamping pressure is calculated based on the diameter value, and the clamping pressure of each chuck structure is obtained based on the reference clamping pressure and the weight of each chuck structure; the clamping pressure of multiple chuck structures is synchronously adjusted based on the calculated clamping pressure of each chuck structure so that the clamping pressure of each chuck structure is maintained within a preset clamping pressure range value.

[0014] Preferably, the displacement of each chuck structure is expressed as:

[0015] ΔX n =(δ×L n) / ΣL×α

[0016] Where ΔX n represents the adjustment displacement of the nth chuck structure, δ represents the deviation, and L n represents the distance between the nth chuck structure and the next adjacent chuck structure. The distance between the end chuck structure is the distance between it and the previous adjacent chuck structure. ΣL represents the sum of the distances between all chuck structures. α represents the temperature compensation factor.

[0017] Preferably, the cutting height calculation formula is expressed as:

[0018] ΔZ=0.8×δ v +0.5×δ r

[0019] Where, δ v Indicates radial runout, δ r Represents the vertical deformation.

[0020] Preferably, in the initial state, the pipe is transported by a conveyor chain, and the linear deviation rate between the pipe axis and the conveying direction is monitored in real time. When it is detected that the linear deviation rate is greater than the linear deviation rate threshold, the chuck structure close to the conveyor chain is moved along the slide rail to the end of the pipe to achieve pre-positioning, and then it also includes: obtaining feedback information from the RFID reading and writing device set on the conveyor chain, and determining the material information of the pipe according to the feedback information; matching the cutting parameter combination from the material database according to the material information of the pipe, and the cutting parameter combination including the initial cutting speed and the initial cutting power.

[0021] Preferably, when the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold, the tube positioning is completed, and the laser cutting mechanism is started to cut the tube. During the cutting operation, the radial runout and vertical deformation of the tube are collected. When the radial runout of the tube is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation. It also includes: determining the material hardness of the tube according to the material information of the tube, and obtaining the wall thickness tolerance and ambient humidity of the tube; predicting the predicted roughness of the cutting surface according to the material hardness, wall thickness tolerance and ambient humidity of the tube; if the predicted roughness of the cutting surface is greater than the preset roughness threshold, adjusting the cutting parameter combination to obtain the optimized cutting power and optimized cutting speed.

[0022] Preferably, the predicted roughness of the cutting surface is expressed as:

[0023] R a =0.8e 0.05HB +0.3|Δt|+0.02φ·(1+0.005)

[0024] HB represents the material hardness, Δt represents the wall thickness tolerance, and φ represents the ambient humidity.

[0025] Preferably, the optimized cutting power and optimized cutting speed are respectively expressed as:

[0026]

[0027] Where, P new represents the optimized cutting power, P0 represents the initial cutting power, V new Indicates the optimized cutting speed, V0 indicates the initial cutting speed, R a Represents the predicted roughness of the cutting surface, R max Indicates the preset roughness threshold.

[0028] Preferably, when the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold, the tube positioning is completed, and the laser cutting mechanism is started to cut the tube. During the cutting operation, the radial runout and vertical deformation of the tube are collected. When the radial runout of the tube is greater than the radial runout threshold, and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation. It also includes: during the cutting operation, the temperature field distribution of the cutting surface is obtained in real time. When the temperature gradient in the local area is greater than 200℃ / mm, the power compensation is calculated based on the maximum temperature, the average temperature and the optimized cutting speed, and the power compensation and the optimized cutting power are added to obtain the real-time cutting power.

[0029] Preferably, the power compensation amount P1 is expressed as:

[0030] P1=η·(T max -T avg )·V new

[0031] Where η represents the energy density coefficient under unit temperature difference, η=0.05W·s / (℃·mm), T max Indicates the maximum temperature, T avg Indicates the average temperature, V new Indicates the optimized cutting speed.

[0032] The long pipe cutting method provided by the present invention monitors the pipe axis deviation in real time and triggers chuck pre-positioning. During positioning, the chuck clamping pressure is intelligently adjusted in combination with the pipe diameter value, and the coaxiality error is controlled within a threshold through a multi-chuck collaborative compensation mechanism, thereby improving positioning accuracy. At the same time, during the cutting operation, the radial runout and vertical deformation of the pipe are collected in real time, and the cutting height is dynamically adjusted based on the dual thresholds, thereby improving the cutting accuracy and processing stability of the long pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0034] Figure 1 is a flow chart of a long pipe cutting method provided by an embodiment of the present invention;

[0035] Figure 2 Schematic diagram of the structure of the pipe cutting system provided by an embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 20. Side mounting bracket; 30. Laser cutting mechanism; 40. Chuck structure. DETAILED DESCRIPTION

[0038] The terms "first," "second," "third," "fourth," and the like (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0039] See also Figure 1 and Figure 2 As shown, the long pipe cutting method of an embodiment of the present invention is implemented based on a pipe cutting system. The pipe cutting system includes a conveyor chain (not shown), a side hanger 10, a laser cutting mechanism 20 and a plurality of chuck structures 30. The conveyor chain and the side hanger 10 are arranged in sequence along the conveying direction, the laser cutting mechanism 20 is arranged on the side hanger 10, and the plurality of chuck structures 30 are arranged on the side hanger at intervals along the conveying direction.

[0040] A long pipe cutting method according to an embodiment of the present invention includes:

[0041] S101. In an initial state, a pipe is conveyed by a conveyor chain, and a linear deviation rate between the pipe axis and the conveying direction is monitored in real time. When the linear deviation rate is detected to be greater than a linear deviation rate threshold, a chuck structure close to the conveyor chain is moved along a slide rail to the end of the pipe to achieve pre-positioning.

[0042] S102. After pre-positioning is completed, the diameter of the pipe is obtained, and the clamping pressure of the multiple chuck structures is synchronously adjusted based on the diameter of the pipe so that the clamping pressure of each chuck structure is maintained within a preset clamping pressure range of 0.2-0.8 MPa.

[0043] S103, measuring the coaxiality errors of the multiple chuck structures in real time, and when the coaxiality error is greater than a coaxiality error threshold, adjusting the displacement of each chuck structure based on a coordinated compensation mechanism of the multiple chuck structures so that the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold;

[0044] S104. When the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold, the pipe positioning is completed, and the laser cutting mechanism is started to cut the pipe. During the cutting operation, the radial runout and vertical deformation of the pipe are collected. When the radial runout of the pipe is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation.

[0045] In this embodiment, the specific number of the chuck structures is determined according to the length of the pipe. For example, three chuck structures may be provided, or four or even more chuck structures may be provided.

[0046] It is understandable that the execution subject of the present invention may be a long pipe cutting device, or a terminal or a server, which is not limited here. The embodiment of the present invention is described by taking the server as the execution subject as an example.

[0047] In this embodiment, in step S101, the conveyor chain transports the pipe at a constant speed (500 mm / s), and laser alignment sensors (accuracy ±0.02 mm, scanning frequency 50 Hz) installed on both sides of the conveyor chain monitor the linear deviation rate ΔL (mm / m) between the pipe axis and the conveying direction in real time.

[0048] In this embodiment, the linear deviation rate threshold is 0.2 mm / m, that is, when the linear deviation rate ΔL>0.2 mm / m is detected for three consecutive samplings, the pipe transmission posture is determined to be abnormal and the pre-positioning program is started.

[0049] In this embodiment, in step S102, after pre-positioning is completed, the diameter value of the pipe is obtained, and the clamping pressure of multiple chuck structures is synchronously adjusted based on the diameter value of the pipe so that the clamping pressure of the chuck structure is maintained within a preset clamping pressure range value, specifically including: after pre-positioning is completed, the diameter value of the pipe is obtained; a reference clamping pressure is calculated based on the diameter value, and the clamping pressure of each chuck structure is obtained based on the reference clamping pressure and the weight of each chuck structure; the clamping pressure of multiple chuck structures is synchronously adjusted based on the calculated clamping pressure of each chuck structure so that the clamping pressure of each chuck structure is maintained within a preset clamping pressure range value.

[0050] In this embodiment, the preset clamping pressure range is 0.2-0.8 MPa.

[0051] Specifically, when obtaining the pipe diameter value through a non-contact linear array CCD sensor or laser scanner installed on the side bracket, diameter data of multiple points are obtained, and abnormal points are eliminated through an algorithm (such as Gaussian filtering), and the average pipe diameter is calculated, and the average pipe diameter is used as the pipe diameter value.

[0052] In this embodiment, the maximum and minimum values ​​in the diameter data at multiple points may be recorded to evaluate the ellipticity.

[0053] If the pipe diameter exceeds the equipment compatibility range (such as D<10mm or D>500mm), an alarm is triggered and the process is suspended.

[0054] If Dmax_Dmin>0.05DDmax_Dmin>0.05D, it is determined that the pipe deformation exceeds the limit and manual intervention is required.

[0055] In this embodiment, in step S103, the coaxiality errors of the multiple chuck structures are measured in real time by a laser interferometer, and the coaxiality error threshold is 0.05 mm.

[0056] In this embodiment, the displacement of each chuck structure is expressed as:

[0057] ΔX n =(δ×L n ) / ΣL×α

[0058] Where ΔX n represents the adjustment displacement of the nth chuck structure, δ represents the deviation, and L n represents the distance between the nth chuck structure and the next adjacent chuck structure. The distance between the end chuck structure is the distance between it and the previous adjacent chuck structure. ΣL represents the sum of the distances between all chuck structures. α represents the temperature compensation factor.

[0059] In this embodiment, in step S104 , the radial runout threshold is 0.1 mm.

[0060] In this embodiment, the cutting height of the laser cutting mechanism is calculated according to the cutting height calculation formula, which is expressed as:

[0061] ΔZ=0.8×δ v +0.5×δ r

[0062] Where, δ v Indicates radial runout, δ r Represents the vertical deformation.

[0063] In this embodiment, in the initial state, the pipe is transported by the conveyor chain, and the linear deviation rate between the pipe axis and the conveying direction is monitored in real time. When it is detected that the linear deviation rate is greater than the linear deviation rate threshold, the chuck structure close to the conveyor chain is moved along the slide rail to the end of the pipe to achieve pre-positioning. It then includes: obtaining feedback information from the RFID reading and writing device set on the conveyor chain, and determining the material information of the pipe based on the feedback information; matching the cutting parameter combination from the material database based on the material information of the pipe, and the cutting parameter combination including the initial cutting speed and the initial cutting power.

[0064] Specifically, a CK-UR0 industrial-grade reader is set at the loading port of the conveyor chain.

[0065] High-temperature resistant RFID tags are embedded in the ends of pipe fittings to store data such as material codes and batch numbers.

[0066] In this embodiment, a material database is pre-built, and an example of the material database is as follows:

[0067] Material Type Thickness (mm) Cutting speed (m / min) Power (kW) 304 stainless steel 3 1.2 3.0 Q235 carbon steel 6 0.8 4.5 6061 aluminum alloy 5 2.5 2.8

[0068] For example, when the material information of the pipe is identified as 304 stainless steel with a thickness of 3 mm, the matching initial cutting speed is 1.2 m / min and the initial cutting power is 3.0 kW.

[0069] Furthermore, when the coaxiality error of multiple chuck structures is not greater than the coaxiality error threshold, the pipe positioning is completed, and the laser cutting mechanism is started to cut the pipe. During the cutting operation, the radial runout and vertical deformation of the pipe are collected. When the radial runout of the pipe is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation. It also includes: determining the material hardness of the pipe according to the material information of the pipe, and obtaining the wall thickness tolerance and ambient humidity of the pipe; predicting the predicted roughness of the cutting surface according to the material hardness, wall thickness tolerance and ambient humidity of the pipe; if the predicted roughness of the cutting surface is greater than the preset roughness threshold, adjusting the cutting parameter combination to obtain the optimized cutting power and optimized cutting speed.

[0070] In this embodiment, the preset roughness threshold is 1.6 μm.

[0071] The predicted roughness of the cutting surface is calculated according to the cutting surface roughness prediction function, and the predicted roughness of the cutting surface R a Expressed as:

[0072] R a =0.8e 0.05HB +0.3|Δt|+0.02φ·(1+0.005)

[0073] HB represents the material hardness, Δt represents the wall thickness tolerance, and φ represents the ambient humidity.

[0074] It can be understood that by increasing the power (+15% / μm tolerance) the local softening caused by frictional heat can be offset, thereby improving the cutting quality, and reducing the speed (-10% / μm tolerance) can reduce the high-frequency vibration generated by high-speed cutting, thereby improving the cutting quality. Therefore, the cutting quality can be improved by reducing the speed or increasing the power.

[0075] In this embodiment, the cutting parameter combination is adjusted according to the power-speed synergy equation. The constraints of the power-speed synergy equation are that the power fluctuation is ≤±20% and the speed variation is ≤±30%. The power-speed synergy equation is expressed as:

[0076]

[0077] Where, P new represents the optimized cutting power, P0 represents the initial cutting power, V new Indicates the optimized cutting speed, V0 indicates the initial cutting speed, R a Represents the predicted roughness of the cutting surface, R max Indicates the preset roughness threshold.

[0078] For example, when cutting a 42CrMo alloy tube with HB=280 (Δt=0.15mm, φ=65%), the initial cutting power is 4.0kW, and the initial cutting speed is 0.8m / min, the predicted roughness of the cut surface is:

[0079] R a =0.8e 0.05×280 +0.3×0.15+0.02×65×(1+0.005×280)=1.72μm.

[0080] The optimized cutting power is:

[0081] P new =4.0kW×[1+0.15×(1.72_1.6)]=4.07kW.

[0082] The optimized cutting speed is:

[0083] V new =0.8m / min×[1_0.1×(1.72_1.6)]=0.78m / min.

[0084] In this embodiment, when the coaxiality error of multiple chuck structures is not greater than the coaxiality error threshold, the tube positioning is completed, and the laser cutting mechanism is started to cut the tube. During the cutting operation, the radial runout and vertical deformation of the tube are collected. When the radial runout of the tube is greater than the radial runout threshold, and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation. It also includes: during the cutting operation, the cutting surface temperature field distribution is obtained in real time. When the local area temperature gradient is greater than 200℃ / mm, the power compensation is calculated based on the maximum temperature, average temperature and optimized cutting speed, and the power compensation and the optimized cutting power are added to obtain the real-time cutting power.

[0085] In this embodiment, the temperature gradient in the local area is greater than 200° C. / mm, that is, the temperature difference between adjacent temperature measuring points with a spacing of 0.3 mm is greater than 60° C.

[0086] The power compensation amount P1 is expressed as:

[0087] P1=η·(T max -T avg )·V new

[0088] Where η represents the energy density coefficient under unit temperature difference, η=0.05W·s / (℃·mm), T max Indicates the maximum temperature, T avg Indicates the average temperature, V new Indicates the optimized cutting speed.

[0089] It is understandable that when the local temperature gradient exceeds 200℃ / mm, it indicates the risk of thermal stress concentration and requires active intervention. The material thermal properties (such as specific heat capacity c = 0.5J / g·℃) are linked to the process parameters through the η parameter to ensure that the power increment can not only compensate for the heat loss (η is positively correlated with the thermal conductivity λ) but also avoid excessive input leading to melting. For example, when T max -T avg =50℃,V new =0.8m / min, the power compensation amount is: P1=0.05*50*0.8=2W.

[0090] In this embodiment, a high-density infrared thermal imager array and embedded thermocouples are used to work together to form a 5×5 grid of temperature measurement points along the cutting path, covering the cutting surface and the heat-affected zone.

[0091] The spatial resolution of the high-density infrared thermal imager array is ≤0.3mm, the embedded thermocouple is K-type, and the response time is <5ms.

[0092] In this embodiment, the instantaneous maximum value is extracted from all temperature measurement points, and noise is eliminated through sliding window filtering to obtain the maximum temperature.

[0093] In this embodiment, a weighted average is performed on the valid temperature measurement points after removing the abnormal values ​​to obtain the average temperature.

[0094] This embodiment provides a long pipe cutting method, which monitors the pipe axis deviation in real time and triggers chuck pre-positioning. During positioning, the chuck clamping pressure is intelligently adjusted based on the pipe diameter value, and the coaxiality error is controlled within a threshold through a multi-chuck collaborative compensation mechanism, thereby improving positioning accuracy. At the same time, during the cutting operation, the radial runout and vertical deformation of the pipe are collected in real time, and the cutting height is dynamically adjusted based on the dual thresholds, thereby improving the cutting accuracy and processing stability of long pipes.

[0095] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present description and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for cutting long pipes, which is implemented based on a pipe cutting system. The pipe cutting system includes a conveyor chain, a side hanging frame, a laser cutting mechanism, and multiple chuck structures. The conveyor chain and the side hanging frame are arranged along the conveying direction, the laser cutting mechanism is arranged on the side hanging frame, and multiple chuck structures are arranged on the side hanging frame at intervals along the conveying direction. The method is characterized in that: The long pipe cutting method comprises: In the initial state, the pipe is transported by the conveyor chain, and the linear deviation rate between the pipe axis and the conveying direction is monitored in real time. When the linear deviation rate is detected to be greater than the linear deviation rate threshold, the chuck structure close to the conveyor chain is moved along the slide rail to the end of the pipe to achieve pre-positioning; After the pre-positioning is completed, the diameter value of the pipe is obtained, and the clamping pressure of the multiple chuck structures is synchronously adjusted based on the diameter value of the pipe so that the clamping pressure of each chuck structure is maintained within a preset clamping pressure range value; When the clamping pressure of each chuck structure is maintained within a preset clamping pressure range, the coaxiality errors of the multiple chuck structures are measured in real time. When the coaxiality error is greater than a coaxiality error threshold, the displacement of each chuck structure is adjusted based on a coordinated compensation mechanism of the multiple chuck structures so that the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold. When the coaxiality error of multiple chuck structures is not greater than the coaxiality error threshold, the pipe positioning is completed and the laser cutting mechanism is started to cut the pipe. During the cutting operation, the radial runout and vertical deformation of the pipe are collected. When the radial runout of the pipe is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation.

2. The long tube cutting method according to claim 1, characterized in that: After the pre-positioning is completed, the diameter value of the pipe is obtained, and the clamping pressure of the multiple chuck structures is synchronously adjusted based on the diameter value of the pipe so that the clamping pressure of the chuck structures is maintained within a preset clamping pressure range, including: After the pre-positioning is completed, the pipe diameter value is obtained; the reference clamping pressure is calculated according to the pipe diameter value, and the clamping pressure of each chuck structure is calculated based on the reference clamping pressure and the weight of each chuck structure; according to the calculated clamping pressure of each chuck structure, the clamping pressure of multiple chuck structures is synchronously adjusted to keep the clamping pressure of each chuck structure within the preset clamping pressure range value.

3. The long tube cutting method according to claim 1, characterized in that: The displacement of each chuck structure is expressed as: ΔX n =(δ×L n ) / ΣL×α Where ΔX n represents the adjustment displacement of the nth chuck structure, δ represents the deviation, and L n represents the distance between the nth chuck structure and the next adjacent chuck structure. The distance between the end chuck structure is the distance between it and the previous adjacent chuck structure. ΣL represents the sum of the distances between all chuck structures. α represents the temperature compensation factor.

4. The long tube cutting method according to claim 1, wherein: The cutting height calculation formula is expressed as: ΔZ=0.8×δ v +0.5×δ r Where, δ v Indicates radial runout, δ r Represents the vertical deformation.

5. The long tube cutting method according to claim 1, wherein: In the initial state, the pipe is conveyed by the conveyor chain, and the linear deviation rate between the pipe axis and the conveying direction is monitored in real time. When the linear deviation rate is detected to be greater than a linear deviation rate threshold, the chuck structure close to the conveyor chain is moved along the slide rail to the end of the pipe to achieve pre-positioning, and then the following steps are further included: Obtain feedback information from the RFID reader / writer device installed on the conveyor chain, and determine the material information of the pipe fittings based on the feedback information; A cutting parameter combination is matched from a material database according to material information of the pipe fitting, where the cutting parameter combination includes an initial cutting speed and an initial cutting power.

6. The long tube cutting method according to claim 5, characterized in that: When the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold, the pipe positioning is completed, and the laser cutting mechanism is started to cut the pipe. During the cutting process, the radial runout and vertical deformation of the pipe are collected. When the radial runout of the pipe is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation. The above also includes: Determine the material hardness of the pipe based on the material information of the pipe fitting, and obtain the wall thickness tolerance of the pipe and the ambient humidity; The predicted roughness of the cutting surface is obtained based on the material hardness, wall thickness tolerance and ambient humidity of the pipe; If the predicted roughness of the cutting surface is greater than a preset roughness threshold, the cutting parameter combination is adjusted to obtain an optimized cutting power and an optimized cutting speed.

7. The long tube cutting method according to claim 6, characterized in that: The predicted roughness of the cutting surface is expressed as: R a =0.8e 0.05HB +0.3|Δt|+0.02φ·(1+0.005) HB represents the material hardness, Δt represents the wall thickness tolerance, and φ represents the ambient humidity.

8. The long tube cutting method according to claim 7, characterized in that: The optimized cutting power and optimized cutting speed are respectively expressed as: Where, P new represents the optimized cutting power, P0 represents the initial cutting power, V new Indicates the optimized cutting speed, V0 indicates the initial cutting speed, R a Represents the predicted roughness of the cutting surface, R max Indicates the preset roughness threshold.

9. The long tube cutting method according to claim 1, wherein: When the coaxiality error of the multiple chuck structures is not greater than the coaxiality error threshold, the pipe positioning is completed, and the laser cutting mechanism is started to cut the pipe. During the cutting operation, the radial runout and vertical deformation of the pipe are collected. When the radial runout of the pipe is greater than the radial runout threshold and the vertical deformation is greater than the vertical deformation threshold, the cutting height of the laser cutting mechanism is adjusted based on the radial runout threshold and the vertical deformation. The method also includes: during the cutting operation, the temperature field distribution of the cutting surface is obtained in real time. When the temperature gradient in the local area is greater than 200°C / mm, the power compensation amount is calculated according to the maximum temperature, the average temperature and the optimized cutting speed, and the power compensation amount and the optimized cutting power are added to obtain the real-time cutting power.

10. The long tube cutting method according to claim 9, characterized in that: The power compensation amount P1 is expressed as: P1=η·(T max -T avg )·V new Where η represents the energy density coefficient under unit temperature difference, η=0.05W·s / (℃·mm), T max Indicates the maximum temperature, T avg Indicates the average temperature, V new Indicates the optimized cutting speed.

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