Forming system and method for thin-wall steel wire reinforced composite pipe

Abstract

The invention relates to the technical field of defect detection of composite pipe forming, in particular to a forming system and method of a thin-wall steel wire reinforced composite pipe. After a forming machine extrudes the composite pipe, a fluorescent coating module continuously coats a fluorescent monitoring area on the surface of the composite pipe, and an optical detection module detects the defect of the composite pipe according to a local fluorescent marker concentration comparison result. Acquiring a first comparison parameter and a second comparison parameter, judging whether a local shrinkage defect exists on the surface of the composite pipe or not through a defect identification module, determining a defect feature category through a defect feature polymerization module, and determining a targeted regulation and control mode through a forming regulation and control module; according to the forming method, different regulation and control modes of the forming machine are determined according to different defect feature categories of the composite pipe. Furthermore, targeted identification and quantitative analysis on local shrinkage defects caused by uneven melting of reclaimed materials and steel wire supporting stress difference in the plastic cooling shrinkage process are realized, and the molding qualification rate and the production efficiency of the composite pipe are improved.

Description

Technical Field

[0001] This invention relates to the field of defect detection technology in composite pipe forming, and in particular to a forming system and method for thin-walled steel wire reinforced composite pipes. Background Technology

[0002] Thin-walled steel wire reinforced composite pipes combine the corrosion resistance of plastics with the structural support of steel wires, making them widely used in water supply and drainage, gas transmission, and industrial fluid transport. The molding quality directly determines the pipe's pressure resistance, sealing performance, and service life. Currently, in response to environmental protection policies and the demand for resource recycling, more and more recycled plastics are being used in the extrusion molding of composite pipes. Due to the uneven melt flow properties and differences in impurity distribution, recycled plastics are more prone to molding defects such as uneven local shrinkage during the extrusion cooling process. If the axial and radial arrangement support characteristics of the steel wires do not match the shrinkage stress of the plastic, this defect will be further aggravated.

[0003] Current technologies mostly rely on manual sampling or simple visual inspection to judge molding quality, lacking real-time and accurate detection methods for the shrinkage state of pipe surfaces. The application of recycled plastics makes the shrinkage characteristics of composite pipes more complex, easily leading to problems such as local wall thickness deviations and surface micro-cracks. This not only reduces the product qualification rate of pipes but also limits the large-scale production of recycled plastics in thin-walled steel wire reinforced composite pipes, which is not conducive to the improvement of the plastic recycling industry chain and the development of green manufacturing.

[0004] For example, Chinese invention patent CN116228769A, published on June 6, 2023, discloses a device and method for detecting defects in steel wire braided tubing, comprising an image acquisition device, an image segmentation module, and an image analysis module connected in sequence. The image acquisition device is used to acquire surface images of the braided tubing; the image segmentation module is used to locate defect areas and generate defect images; the image analysis module classifies the defect images using a convolutional neural network; wherein, the image segmentation module includes a stacked autoencoder, a binarization module, and an image cropping module; the stacked autoencoder is used to convert the input image into a prediction mask, the binarization module is used to binarize the prediction mask to obtain accurate defect contours, and the image cropping module is used to extract the smallest closed rectangular region based on the defect contours and crop accordingly to obtain the defect image.

[0005] Existing technologies cannot identify and quantitatively analyze local shrinkage defects caused by uneven melting of recycled materials and differences in the support stress of steel wires during the cooling and shrinkage process of plastics. They also lack matching control strategies for shrinkage defects of different causes, which affects the pass rate of composite pipe molding and production efficiency. Summary of the Invention

[0006] To address this, the present invention provides a molding system and method for thin-walled steel wire reinforced composite pipes, which overcomes the problems of existing technologies being unable to specifically identify and quantitatively analyze local shrinkage defects caused by uneven melting of recycled materials and differences in steel wire support stress during the cooling and shrinkage process of plastics, and the lack of matching control strategies for shrinkage defects of different causes.

[0007] To achieve the above objectives, the present invention provides a forming system for thin-walled steel wire reinforced composite pipes, comprising: A molding machine, used to extrude composite pipes; A fluorescent coating module is used to continuously coat circular fluorescent monitoring areas on the surface of a composite tube at preset intervals. An optical detection module, connected to the fluorescent coating module, is used to obtain a first comparison parameter and a second comparison parameter of the fluorescence monitoring area based on the comparison results of the local fluorescent marker concentration in the fluorescence monitoring area. The methods for dividing the fluorescence monitoring area are different in the acquisition processes of the first and second comparison parameters. A defect identification module, which is connected to the optical detection module, is used to determine the comparison results of the first comparison parameter and the second comparison parameter with the corresponding preset reference parameters, so as to determine whether there are local shrinkage defects on the surface of the composite pipe. A defect feature aggregation module, which is connected to the optical detection module and the defect identification module respectively, is used to statistically analyze the numerical values ​​of the first comparison parameter and the second comparison parameter in several continuously acquired fluorescence monitoring areas to determine the defect feature category. The molding control module is connected to both the defect feature aggregation module and the molding machine, and is used to determine the control mode of the molding machine according to the defect feature category, including adjusting the arrangement density of axial or radial steel wires or adjusting the extrusion rate.

[0008] Furthermore, the optical detection module is used to obtain a first comparison parameter based on the comparison result of the local fluorescent marker concentration in the fluorescence monitoring area, wherein, The optical detection module uses the diameter perpendicular to the axial direction of the composite tube as a reference to divide the fluorescence monitoring area into two radial sub-regions, calculates the concentration difference of the fluorescent marker in the two radial sub-regions, and determines the concentration difference of the fluorescent marker as the first comparison parameter.

[0009] Furthermore, the optical detection module is used to obtain a second comparison parameter based on the comparison result of the local fluorescent marker concentration in the fluorescence monitoring area, wherein, The optical detection module uses the diameter parallel to the axial direction of the composite tube as a reference to divide the fluorescence monitoring area into two axial sub-regions, calculates the concentration difference of the fluorescent marker in the two axial sub-regions, and determines the concentration difference of the fluorescent marker as the second comparison parameter.

[0010] Furthermore, the defect identification module is used to determine whether there are local shrinkage defects on the surface of the composite pipe, wherein, The defect identification module compares the first comparison parameter with the first preset reference parameter, and compares the second comparison parameter with the second preset reference parameter; If the first comparison parameter is greater than the first preset reference parameter, or if the second comparison parameter is greater than the second preset reference parameter, then the defect identification module determines that there is a local shrinkage defect on the surface of the composite pipe.

[0011] Furthermore, the defect feature aggregation module is used to statistically analyze the numerical values ​​of the first comparison parameter and the second comparison parameter, wherein, The defect feature aggregation module compares the values ​​of the first comparison parameter and the second comparison parameter for each of the several continuously acquired fluorescence monitoring regions, counts the number of times the value of the first comparison parameter is greater than the value of the second comparison parameter, and calculates the ratio of the number of occurrences to the number of times the fluorescence monitoring region is acquired.

[0012] Furthermore, the defect feature aggregation module is used to determine the defect feature category based on the ratio, wherein, The defect feature aggregation module compares the ratio with a preset first ratio reference value and a preset second ratio reference value, respectively; If the ratio is greater than the first ratio reference value, or if the ratio is less than the second ratio reference value, then the defect feature aggregation module determines the local shrinkage defect as the first defect feature category; If the ratio is less than or equal to the first ratio reference value, and the ratio is greater than or equal to the second ratio reference value, then the defect feature aggregation module determines the local shrinkage defect as the second defect feature category. The first ratio reference value is greater than the second ratio reference value.

[0013] Furthermore, the molding control module is used to determine the control mode of the molding machine according to the defect characteristic category, wherein, If the local shrinkage defect is the first defect feature category, the forming control module controls the forming machine to adjust the arrangement density of the axial or radial steel wires; If the local shrinkage defect is classified as the second defect characteristic category, the molding control module adjusts the extrusion rate of the molding machine.

[0014] Furthermore, the forming control module is used to control the forming machine to adjust the arrangement density of the axial or radial steel wires, wherein, If the ratio is greater than the first ratio reference value, the forming control module increases the radial steel wire arrangement density, and the increase in the radial steel wire arrangement density is positively correlated with the ratio. If the ratio is less than the second ratio reference value, the forming control module increases the axial steel wire arrangement density, and the increase in the axial steel wire arrangement density is negatively correlated with the ratio.

[0015] Furthermore, the molding control module is used to control the molding machine to reduce the extrusion rate.

[0016] Furthermore, the present invention also provides a method for forming a thin-walled steel wire reinforced composite pipe, comprising: Circular fluorescent monitoring areas are continuously coated on the surface of the extruded composite tube at preset intervals; Based on the comparison results of local fluorescent marker concentrations in the fluorescence monitoring area, a first comparison parameter and a second comparison parameter of the fluorescence monitoring area are obtained. The methods of dividing the fluorescence monitoring area are different in the process of obtaining the first comparison parameter and the second comparison parameter. The comparison results of the first comparison parameter and the second comparison parameter with the corresponding preset reference parameters are determined respectively, and the presence of local shrinkage defects on the surface of the composite pipe is determined based on the comparison results. In response to the determination that there are local shrinkage defects on the surface of the composite pipe, the numerical values ​​of the first comparison parameter and the second comparison parameter in several continuously acquired fluorescence monitoring areas are statistically analyzed to determine the defect feature category. The control method of the molding machine is determined according to the defect feature category. The control method includes adjusting the arrangement density of axial or radial steel wires or adjusting the extrusion rate.

[0017] The beneficial effects of the technical solution shown in this application include: extruding a composite tube using a molding machine; continuously coating a fluorescent monitoring area on the surface of the composite tube using a fluorescent coating module; acquiring a first and second comparison parameters for local fluorescent marker concentration comparison using an optical detection module; determining whether local shrinkage defects exist on the surface of the composite tube using a defect identification module; statistically analyzing the values ​​of the first and second comparison parameters using a defect feature aggregation module to determine the defect feature category; and adjusting the arrangement density of axial or radial steel wires, or adjusting the extrusion rate, using a molding control module. The molding method of this invention determines different control methods for the molding machine based on different defect feature categories of the composite tube. Furthermore, it achieves targeted identification and quantitative analysis of local shrinkage defects caused by uneven melting of recycled materials and differences in steel wire support stress during the cooling and shrinkage process of plastic, as well as matching control strategies for shrinkage defects of different causes, thereby improving the composite tube molding pass rate and production efficiency.

[0018] Furthermore, during the extrusion cooling process, the radial shrinkage deformation of the composite tube of the present invention is directly reflected as a change in the microstructure of the tube wall surface. When there is uneven shrinkage defect in the radial direction, the local stretching and extrusion of the tube wall will cause the coated fluorescent marker to produce a difference in concentration distribution in the corresponding area. The two radial sub-regions after division form a comparative reference system, realizing the quantitative analysis of the plastic cooling shrinkage process.

[0019] Furthermore, the fluorescent markers on the surface of the composite tube of the present invention will form a concentration difference due to the axial shrinkage effect. By dividing the fluorescence monitoring area with the diameter parallel to the axial direction as the reference, two symmetrical sub-regions along the axial direction of the composite tube can be accurately divided. The magnitude of the concentration difference can directly characterize the severity of the axial shrinkage defect, realizing the quantitative analysis of the plastic cooling shrinkage process.

[0020] Furthermore, in the first defect feature category of the present invention, the defect is a regular shrinkage defect caused by the difference in supporting stress of the axial or radial steel wires, and this type of defect has a clear shrinkage direction. In the second defect feature category, the radial and axial steel wire shrinkage defects do not have a clear dominant tendency, and the defect is an irregular shrinkage defect caused by uneven melting of recycled plastic, and this type of defect has no fixed directional tendency. Thus, the local shrinkage defects caused by uneven melting of recycled material and the difference in supporting stress of steel wires during the cooling and shrinkage of plastic can be specifically identified.

[0021] Furthermore, the first defect feature category in this invention corresponds to a regular local shrinkage defect caused by the difference in axial or radial support stress of the steel wire. The core cause of this type of defect is the mismatch between the steel wire arrangement density and the cooling shrinkage stress of the composite pipe. Therefore, a targeted adjustment method is adopted to adjust the axial or radial arrangement density of the steel wire to change the support strength of the steel wire in the corresponding direction, thereby eliminating the regular shrinkage defect from the root and realizing a matching control strategy for shrinkage defects with different causes, which improves the composite pipe forming qualification rate and production efficiency.

[0022] Furthermore, the second defect feature category in this invention corresponds to irregular local shrinkage defects caused by insufficient melt uniformity of recycled plastics. The core cause is that the process parameters of melt flow and cooling solidification during plastic extrusion molding are not compatible with the material properties of recycled plastics. By adjusting the extrusion rate of the molding machine, the degree of melting and plasticization of the recycled plastic melt can be controlled to improve the uniformity of the melt. This achieves a matching and control strategy for shrinkage defects of different causes, thereby improving the composite pipe molding qualification rate and production efficiency. Attached Figure Description

[0023] Figure 1 This is a system block diagram of the forming system for the thin-walled steel wire reinforced composite pipe according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the logic of determining whether there are local shrinkage defects on the surface of a composite pipe according to an embodiment of the present invention. Figure 3 A flowchart illustrating the logic for determining defect feature categories in an embodiment of the present invention; Figure 4 A logic flowchart for determining the control method of the molding machine in an embodiment of the present invention; Figure 5 This is a step diagram illustrating the molding method of a thin-walled steel wire reinforced composite pipe according to an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0025] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0026] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," "outer," etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0027] It should be understood that although the terms "first," "second," etc., may be used in this invention to describe various types of information, these information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information.

[0028] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Please see Figure 1 The diagram shown is a system block diagram of the forming system for a thin-walled steel wire reinforced composite pipe according to an embodiment of the present invention. The forming system for the thin-walled steel wire reinforced composite pipe of the present invention includes: A molding machine, used to extrude composite pipes; This invention does not limit the results of the molding machine. For example, a single-screw extruder can be used, and the core structure includes a barrel, a screw, and a molding die. The barrel temperature is adjustable from 160℃ to 200℃, and the screw speed is adjusted by frequency conversion speed regulation, thereby controlling the extrusion rate of the composite pipe. Molding machines are widely used in the molding production of pipes, and will not be described in detail here.

[0030] A fluorescent coating module is used to continuously coat circular fluorescent monitoring areas on the surface of a composite tube at preset intervals. In this invention, the diameter d of the circular fluorescence monitoring area a The value is based on the diameter d of the composite pipe. b Confirmed, d a =δ×d b δ is a diameter factor for the fluorescence monitoring area, and optionally, the value of δ can be 0.7. The preset distance between two adjacent fluorescence monitoring areas along the axial direction of the composite tube is 0.5m.

[0031] In this invention, the fluorescence monitoring area is set to a circle, which makes it easy to divide it into sub-regions with the diameter as the axis of symmetry.

[0032] In this invention, the fluorescent marker coated on the fluorescence monitoring area can be a water-based erasable fluorescent ink with a fluorescence emission wavelength of 450nm-650nm and a coating thickness of 20μm. The fluorescent marker is applied after the composite tube is extruded by the molding machine and before the composite tube is cooled by cold water.

[0033] This invention does not limit the fluorescent coating module, which includes a coating nozzle for continuously coating circular fluorescent monitoring areas on the surface of a composite tube at preset distance intervals, and a distance sensor for measuring distance along the axial direction of the composite tube. To ensure that adjacent fluorescent monitoring areas are set at preset distance intervals, when the measured distance value reaches the preset distance interval, the distance sensor sends a trigger signal to the solenoid valve of the coating nozzle. After receiving the signal, the solenoid valve of the coating nozzle immediately sprays out fluorescent markers to form fluorescent monitoring areas on the surface of the composite tube. At the same time, the distance sensor is zeroed and enters the next distance measurement cycle.

[0034] During implementation, the distance between the coating nozzle and the surface of the composite pipe is 10mm.

[0035] An optical detection module, connected to the fluorescent coating module, is used to obtain a first comparison parameter and a second comparison parameter of the fluorescence monitoring area based on the comparison results of the local fluorescent marker concentration in the fluorescence monitoring area. The methods for dividing the fluorescence monitoring area are different in the acquisition processes of the first and second comparison parameters. The present invention does not limit the optical detection module, which includes a fluorescence spectrometer for detecting the concentration of fluorescent markers in the fluorescence monitoring area. In order to ensure that the coated fluorescent markers have sufficient cooling time to allow the composite tube to cool and shrink naturally and cause concentration differences, the fluorescence spectrometer performs concentration detection 5 seconds after the fluorescent markers are coated, and the fluorescent marker concentration detection operation is completed before the composite tube enters the cold water cooling process.

[0036] A defect identification module, which is connected to the optical detection module, is used to determine the comparison results of the first comparison parameter and the second comparison parameter with the corresponding preset reference parameters, so as to determine whether there are local shrinkage defects on the surface of the composite pipe. The present invention does not limit the defect identification module, which has a built-in data storage and processor. The data storage pre-stores a first preset reference parameter and a second preset reference parameter, and the processor is used to determine the comparison result of the data.

[0037] A defect feature aggregation module, which is connected to the optical detection module and the defect identification module respectively, is used to statistically analyze the numerical values ​​of the first comparison parameter and the second comparison parameter in several continuously acquired fluorescence monitoring areas to determine the defect feature category. The present invention does not limit the defect feature aggregation module, which includes a register for storing data and a programmable logic component connected to the register for logical comparison of the stored data.

[0038] In this invention, the number of fluorescence monitoring regions continuously acquired by the defect feature aggregation module ranges from 10 to 30, and optionally, the number of continuously acquired fluorescence monitoring regions is 15.

[0039] The molding control module is connected to both the defect feature aggregation module and the molding machine, and is used to determine the control mode of the molding machine according to the defect feature category, including adjusting the arrangement density of axial or radial steel wires or adjusting the extrusion rate.

[0040] The present invention does not limit the molding control module, which can be a microprocessor or a processor used in a computer, and will not be elaborated here.

[0041] Specifically, the optical detection module is used to obtain a first comparison parameter based on the comparison result of the local fluorescent marker concentration in the fluorescence monitoring area, wherein, The optical detection module uses the diameter perpendicular to the axial direction of the composite tube as a reference to divide the fluorescence monitoring area into two radial sub-regions, calculates the concentration difference of the fluorescent marker in the two radial sub-regions, and determines the concentration difference of the fluorescent marker as the first comparison parameter.

[0042] Those skilled in the art will understand that during the extrusion and cooling process of the composite tube, the radial shrinkage deformation directly reflects the microscopic morphological changes on the tube wall surface. When uneven shrinkage defects exist in the radial direction, the local stretching and compression of the tube wall will cause differences in the concentration distribution of the coated fluorescent marker in the corresponding area. The two divided radial sub-regions form a comparative reference system. The concentration difference of the fluorescent marker can quantitatively characterize the degree of shrinkage difference between the radial sub-regions. The larger the concentration difference, the more significant the radial shrinkage unevenness of the composite tube, thus realizing the quantitative analysis of the plastic cooling and shrinkage process.

[0043] Specifically, the optical detection module is used to obtain a second comparison parameter based on the comparison result of the local fluorescent marker concentration in the fluorescence monitoring area, wherein, The optical detection module uses the diameter parallel to the axial direction of the composite tube as a reference to divide the fluorescence monitoring area into two axial sub-regions, calculates the concentration difference of the fluorescent marker in the two axial sub-regions, and determines the concentration difference of the fluorescent marker as the second comparison parameter.

[0044] Those skilled in the art will understand that when there is uneven shrinkage defect in the axial direction, the fluorescent markers on the pipe wall surface will form a concentration difference due to the axial shrinkage effect. By dividing the fluorescence monitoring area with the diameter parallel to the axial direction as the benchmark, two symmetrical sub-regions in the axial direction of the composite pipe can be accurately divided. The magnitude of the concentration difference can directly characterize the severity of the axial shrinkage defect, thus realizing the quantitative analysis of the plastic cooling shrinkage process.

[0045] For example, when calculating the difference in fluorescent marker concentration between two radial sub-regions or between two axial sub-regions, it is necessary to calculate the arithmetic mean of the fluorescent marker concentration at all detection points within each sub-region. The absolute value of the difference between the arithmetic mean of the fluorescent marker concentration between the two radial sub-regions is determined as the first comparison parameter; the absolute value of the difference between the arithmetic mean of the fluorescent marker concentration between the two axial sub-regions is determined as the second comparison parameter.

[0046] During implementation, the detection points in each sub-region are selected uniformly in a grid pattern within the sub-region, with a grid spacing of 2mm.

[0047] Specifically, please refer to Figure 2 The diagram shown is a flowchart illustrating the logic of determining whether a local shrinkage defect exists on the surface of a composite pipe according to an embodiment of the present invention. The defect identification module is used to determine whether a local shrinkage defect exists on the surface of the composite pipe. The defect identification module compares the first comparison parameter with the first preset reference parameter, and compares the second comparison parameter with the second preset reference parameter; If the first comparison parameter is greater than the first preset reference parameter, or if the second comparison parameter is greater than the second preset reference parameter, then the defect identification module determines that there is a local shrinkage defect on the surface of the composite pipe. If the first comparison parameter is less than or equal to the first preset reference parameter, and the second comparison parameter is less than or equal to the second preset reference parameter, then the defect identification module determines that there is no local shrinkage defect on the surface of the composite pipe.

[0048] In the implementation of this invention, through hundreds of comparative experiments on the molding of thin-walled steel wire reinforced composite pipes based on recycled plastic, the values ​​of the first preset reference parameter and the second preset reference parameter are determined. For example, under the conditions that the composite pipe substrate is recycled polyethylene, the substrate shrinkage rate is 1.5%-3%, the steel wire is low carbon steel wire with a diameter of 1mm, and the pipe wall thickness is 8mm, the basic extrusion rate of the molding machine is set to 2m / min, the barrel temperature is 160℃-200℃, and the average difference in fluorescent marker concentration between two radial sub-regions and between two axial sub-regions of several fluorescence monitoring areas is recorded. The obtained average difference is determined as the first preset reference parameter and the second preset reference parameter, respectively.

[0049] Optionally, the first preset reference parameter in this embodiment of the invention is 0.1 mg / cm³. 2 The second preset reference parameter is set to 0.1 mg / cm³. 2 .

[0050] It is understandable that by comparing the first comparison parameter with the first preset reference parameter and the second comparison parameter with the second preset reference parameter respectively, it is possible to independently determine the radial and axial contraction states and identify uneven contraction problems that exist in one direction or both directions simultaneously.

[0051] Specifically, the defect feature aggregation module is used to statistically analyze the numerical values ​​of the first comparison parameter and the second comparison parameter, wherein... The defect feature aggregation module compares the values ​​of the first comparison parameter and the second comparison parameter for each of the several continuously acquired fluorescence monitoring regions, counts the number of times the value of the first comparison parameter is greater than the value of the second comparison parameter, and calculates the ratio of the number of occurrences to the number of times the fluorescence monitoring region is acquired.

[0052] For example, if the defect feature aggregation module continuously acquires N fluorescence monitoring regions, and compares the first comparison parameter and the second comparison parameter corresponding to each fluorescence monitoring region, and counts that the first comparison parameter is greater than the second comparison parameter M times, then the defect feature aggregation module calculates the ratio R = M / N of the number of occurrences to the number of fluorescence monitoring regions acquired.

[0053] Understandably, comparing the parameters of several consecutive fluorescent monitoring areas can eliminate random errors in the local forming of the pipe and accurately capture the overall pattern of shrinkage defects in the entire pipe section. By comparing the parameter values ​​of consecutive monitoring areas one by one and counting the number of times the first comparison parameter is greater than the second comparison parameter, the frequency ratio of radial shrinkage defects to axial shrinkage defects can be intuitively quantified, reflecting the dominant difference between radial and axial shrinkage defects in the composite pipe forming process. The change in the ratio can directly reflect the regularity of shrinkage defects in a certain direction.

[0054] Specifically, please refer to Figure 3 The diagram shown is a logical flowchart for determining the defect feature category according to an embodiment of the present invention. The defect feature aggregation module is used to determine the defect feature category based on the ratio, wherein... The defect feature aggregation module compares the ratio with a preset first ratio reference value and a preset second ratio reference value, respectively; If the ratio is greater than the first ratio reference value, or if the ratio is less than the second ratio reference value, then the defect feature aggregation module determines the local shrinkage defect as the first defect feature category; If the ratio is less than or equal to the first ratio reference value, and the ratio is greater than or equal to the second ratio reference value, then the defect feature aggregation module determines the local shrinkage defect as the second defect feature category. The first ratio reference value is greater than the second ratio reference value.

[0055] In this invention, the first ratio reference value is 0.75 and the second ratio reference value is 0.25. Those skilled in the art can make adaptive adjustments to the specific values ​​of the two ratio reference values ​​to achieve the classification of defect feature categories.

[0056] It is understood that the first defect feature category of this invention refers to regular shrinkage defects caused by differences in the supporting stress of axial or radial steel wires, which exhibit a clear direction of shrinkage. In the second defect feature category, radial and axial steel wire shrinkage defects do not show a clear dominant tendency; instead, they are irregular shrinkage defects caused by uneven melting of recycled plastic, which do not have a fixed directional tendency. Therefore, this invention enables targeted identification and quantitative analysis of localized shrinkage defects caused by uneven melting of recycled material and differences in the supporting stress of steel wires during the cooling and shrinkage process of plastic.

[0057] Specifically, please refer to Figure 4 As shown, this is a logic flowchart of an embodiment of the present invention for determining the control mode of the molding machine. The molding control module is used to determine the control mode of the molding machine according to the defect feature category. If the local shrinkage defect is the first defect feature category, the forming control module controls the forming machine to adjust the arrangement density of the axial or radial steel wires; If the local shrinkage defect is classified as the second defect characteristic category, the molding control module adjusts the extrusion rate of the molding machine.

[0058] In the actual engineering production of thin-walled steel wire reinforced composite pipes, axial and radial steel wires are typically arranged in a left-right spiral cross-winding manner to form a mesh reinforcement structure. The axial steel wires are arranged along the axial direction of the composite pipe, while the radial steel wires are arranged in a circumferential direction perpendicular to the axial direction. Both the axial and radial steel wire arrangement densities are conventional process parameters that are adjustable and controllable. The number of steel wires per unit length is generally adjusted on the production line through a wire arrangement mechanism. Adjusting the axial or radial steel wire arrangement density by increasing the wire arrangement density in the corresponding direction by reducing the wire arrangement spacing is well known to those skilled in the art and will not be elaborated upon here.

[0059] The extrusion rate is determined by the rotation speed of the molding machine host. The screw rotation speed is controlled by frequency conversion speed regulation, thereby changing the speed at which the plastic melt is extruded from the die. On-site operators can adjust the extrusion rate by adjusting the frequency of the frequency converter. This is a technical parameter well known to those skilled in the art, and will not be elaborated here.

[0060] Understandably, the first defect category corresponds to regular local shrinkage defects caused by differences in axial or radial support stress of the steel wires. The core cause of this type of defect is the mismatch between the steel wire density and the cooling shrinkage stress of the composite pipe. Therefore, a targeted control method is adopted to adjust the axial or radial density of the steel wires, changing the support strength of the steel wires in the corresponding direction, thus eliminating the regular shrinkage defect at its source. The second defect category corresponds to irregular local shrinkage defects caused by insufficient uniformity of recycled plastic melt. The core cause is that the process parameters of melt flow and cooling solidification during plastic extrusion molding are not compatible with the material properties of recycled plastic. By adjusting the extrusion rate of the molding machine, the degree of melting and plasticization of the recycled plastic melt can be controlled, thereby improving the uniformity of the melt. This achieves a matching control strategy for shrinkage defects of different causes, improving the composite pipe molding qualification rate and production efficiency.

[0061] Specifically, the forming control module is used to control the forming machine to adjust the arrangement density of the axial or radial steel wires, wherein, If the ratio is greater than the first ratio reference value, the forming control module increases the radial steel wire arrangement density, and the increase in the radial steel wire arrangement density is positively correlated with the ratio. If the ratio is less than the second ratio reference value, the forming control module increases the axial steel wire arrangement density, and the increase in the axial steel wire arrangement density is negatively correlated with the ratio.

[0062] For example, the increase in radial wire density = initial value of radial wire density × (ratio - first ratio reference value) × k, and the increase in axial wire density = initial value of axial wire density × (second ratio reference value - ratio) × k, where k is a correction coefficient, and the value range of k is [1, 1.2]. Optionally, in the implementation of the present invention, k = 1.1. In the present invention, the initial values ​​of radial wire density and axial wire density of the thin-walled steel wire reinforced composite pipe are determined according to the specifications of the steel wire mesh in the process requirements.

[0063] It is understandable that when the statistical ratio is greater than the first ratio reference value, it indicates that the radial shrinkage defect of the composite pipe is significantly dominated by regularity. The core cause is that the radial steel wire support strength is insufficient and cannot offset the radial shrinkage stress generated during the cooling process of recycled plastic. Therefore, the radial steel wire arrangement density is increased in a targeted manner to achieve the purpose of improving the overall support force in the radial direction. The larger the ratio, the more significant the radial shrinkage unevenness, corresponding to a larger increase in density, so as to achieve precise compensation for the radial support stress. It is understandable that if the statistical ratio is less than the second reference value, it means that the axial shrinkage defect of the composite pipe is the main regular defect. The root cause is that the axial steel wire support force cannot match the axial shrinkage stress. Therefore, the axial steel wire arrangement density is increased to improve the axial support strength. When the ratio is smaller, that is, when the axial shrinkage defect is more serious, the corresponding axial steel wire density increases by a larger amount.

[0064] Specifically, the molding control module is used to control the molding machine to reduce the extrusion rate.

[0065] For example, when the ratio R is in the range of [0.25, 0.75], the local shrinkage defect is determined to be the second defect feature category, and the molding machine is controlled to reduce the extrusion rate; When R∈[0.45,0.55], the reduction in extrusion rate of the molding machine = initial extrusion rate × 25%; When R∈[0.35,0.45)∪(0.55,0.65], the reduction in extrusion rate of the molding machine = initial extrusion rate × 15%; When R∈[0.25,0.35)∪(0.65,0.75], the reduction in extrusion rate of the molding machine = initial value of extrusion rate × 10%.

[0066] It is understood that the irregular shrinkage defect corresponding to the second defect feature category of this invention is primarily caused by the uneven melt flow properties of recycled plastic. By reducing the extrusion rate of the molding machine, the plasticizing time of the recycled plastic in the barrel can be extended, allowing the molten recycled plastic to undergo more thorough shearing and mixing, effectively improving the homogeneity of the melt and reducing the differences in cooling shrinkage caused by uneven melt composition and viscosity distribution. Simultaneously, a lower extrusion rate can slow down the extrusion molding rhythm of the composite pipe, making the flow of molten plastic in the molding die more stable. This, in turn, improves the composite pipe molding pass rate and production efficiency.

[0067] Specifically, please refer to Figure 5 The diagram shows the steps of the forming method for the thin-walled steel wire reinforced composite pipe according to an embodiment of the present invention. The forming method for the thin-walled steel wire reinforced composite pipe of the present invention includes: Step S1: Circular fluorescence monitoring areas are continuously coated on the surface of the extruded composite tube at preset intervals; Step S2: Based on the comparison results of local fluorescent marker concentrations in the fluorescence monitoring area, obtain the first comparison parameter and the second comparison parameter of the fluorescence monitoring area. The fluorescence monitoring area is divided in different ways during the acquisition of the first comparison parameter and the second comparison parameter. Step S3: Determine the comparison results of the first comparison parameter and the second comparison parameter with the corresponding preset reference parameters, and determine whether there are local shrinkage defects on the surface of the composite pipe based on the comparison results; Step S4: In response to the determination that there is a local shrinkage defect on the surface of the composite pipe, the numerical values ​​of the first comparison parameter and the second comparison parameter in several continuously acquired fluorescence monitoring areas are statistically analyzed to determine the defect feature category. Step S5: Determine the control method of the molding machine according to the defect feature category. The control method includes adjusting the arrangement density of axial or radial steel wires or adjusting the extrusion rate.

[0068] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A forming system for a thin-walled steel wire reinforced composite pipe, characterized in that, include: A molding machine, used to extrude composite pipes; A fluorescent coating module is used to continuously coat circular fluorescent monitoring areas on the surface of a composite tube at preset intervals. An optical detection module, connected to the fluorescent coating module, is used to obtain a first comparison parameter and a second comparison parameter of the fluorescence monitoring area based on the comparison results of the local fluorescent marker concentration in the fluorescence monitoring area. The methods for dividing the fluorescence monitoring area are different in the acquisition processes of the first and second comparison parameters. A defect identification module, which is connected to the optical detection module, is used to determine the comparison results of the first comparison parameter and the second comparison parameter with the corresponding preset reference parameters, so as to determine whether there are local shrinkage defects on the surface of the composite pipe. A defect feature aggregation module, which is connected to the optical detection module and the defect identification module respectively, is used to statistically analyze the numerical values ​​of the first comparison parameter and the second comparison parameter in several continuously acquired fluorescence monitoring areas to determine the defect feature category. The molding control module is connected to both the defect feature aggregation module and the molding machine, and is used to determine the control mode of the molding machine according to the defect feature category, including adjusting the arrangement density of axial or radial steel wires or adjusting the extrusion rate.

2. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 1, characterized in that, The optical detection module is used to obtain a first comparison parameter based on the comparison results of the local fluorescent marker concentration in the fluorescence monitoring area, wherein... The optical detection module uses the diameter perpendicular to the axial direction of the composite tube as a reference to divide the fluorescence monitoring area into two radial sub-regions, calculates the concentration difference of the fluorescent marker in the two radial sub-regions, and determines the concentration difference of the fluorescent marker as the first comparison parameter.

3. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 1, characterized in that, The optical detection module is used to obtain a second comparison parameter based on the comparison results of the local fluorescent marker concentration in the fluorescence monitoring area, wherein... The optical detection module uses the diameter parallel to the axial direction of the composite tube as a reference to divide the fluorescence monitoring area into two axial sub-regions, calculates the concentration difference of the fluorescent marker in the two axial sub-regions, and determines the concentration difference of the fluorescent marker as the second comparison parameter.

4. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 1, characterized in that, The defect identification module is used to determine whether there are local shrinkage defects on the surface of the composite pipe. The defect identification module compares the first comparison parameter with the first preset reference parameter, and compares the second comparison parameter with the second preset reference parameter; If the first comparison parameter is greater than the first preset reference parameter, or if the second comparison parameter is greater than the second preset reference parameter, then the defect identification module determines that there is a local shrinkage defect on the surface of the composite pipe.

5. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 4, characterized in that, The defect feature aggregation module is used to statistically analyze the numerical values ​​of the first comparison parameter and the second comparison parameter. The defect feature aggregation module compares the values ​​of the first comparison parameter and the second comparison parameter for each of the several continuously acquired fluorescence monitoring regions, counts the number of times the value of the first comparison parameter is greater than the value of the second comparison parameter, and calculates the ratio of the number of occurrences to the number of times the fluorescence monitoring region is acquired.

6. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 5, characterized in that, The defect feature aggregation module is used to determine the defect feature category based on the ratio, wherein, The defect feature aggregation module compares the ratio with a preset first ratio reference value and a preset second ratio reference value, respectively; If the ratio is greater than the first ratio reference value, or if the ratio is less than the second ratio reference value, then the defect feature aggregation module determines the local shrinkage defect as the first defect feature category; If the ratio is less than or equal to the first ratio reference value, and the ratio is greater than or equal to the second ratio reference value, then the defect feature aggregation module determines the local shrinkage defect as the second defect feature category. The first ratio reference value is greater than the second ratio reference value.

7. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 6, characterized in that, The molding control module is used to determine the control mode of the molding machine according to the defect characteristic category, wherein, If the local shrinkage defect is the first defect feature category, the forming control module controls the forming machine to adjust the arrangement density of the axial or radial steel wires; If the local shrinkage defect is classified as the second defect characteristic category, the molding control module adjusts the extrusion rate of the molding machine.

8. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 7, characterized in that, The forming control module is used to control the forming machine to adjust the arrangement density of axial or radial steel wires, wherein, If the ratio is greater than the first ratio reference value, the forming control module increases the radial steel wire arrangement density, and the increase in the radial steel wire arrangement density is positively correlated with the ratio. If the ratio is less than the second ratio reference value, the forming control module increases the axial steel wire arrangement density, and the increase in the axial steel wire arrangement density is negatively correlated with the ratio.

9. The forming system for the thin-walled steel wire reinforced composite pipe according to claim 7, characterized in that, The molding control module is used to control the molding machine to reduce the extrusion rate.

10. A method for forming a thin-walled steel wire reinforced composite pipe, used in the forming system for the thin-walled steel wire reinforced composite pipe according to any one of claims 1-9, characterized in that, include: Circular fluorescent monitoring areas are continuously coated on the surface of the extruded composite tube at preset intervals; Based on the comparison results of local fluorescent marker concentrations in the fluorescence monitoring area, a first comparison parameter and a second comparison parameter of the fluorescence monitoring area are obtained. The methods of dividing the fluorescence monitoring area are different in the process of obtaining the first comparison parameter and the second comparison parameter. The comparison results of the first comparison parameter and the second comparison parameter with the corresponding preset reference parameters are determined respectively, and the presence of local shrinkage defects on the surface of the composite pipe is determined based on the comparison results. In response to the determination that there are local shrinkage defects on the surface of the composite pipe, the numerical values ​​of the first comparison parameter and the second comparison parameter in several continuously acquired fluorescence monitoring areas are statistically analyzed to determine the defect feature category. The control method of the molding machine is determined according to the defect feature category. The control method includes adjusting the arrangement density of axial or radial steel wires or adjusting the extrusion rate.

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