A method of manufacturing a heat shrink sleeve

Abstract

The present application relates to the technical field of sleeve manufacturing, and particularly relates to a manufacturing method of heat-shrinkable sleeve, comprising the following steps: determining whether a to-be-expanded sleeve sample appears wrinkles in an expansion process based on a wrinkle state evaluation value; extracting wrinkle features of a wrinkle area of the to-be-expanded sleeve sample in the expansion process, determining whether expansion uniformity of the to-be-expanded sleeve sample is up to standard based on wrinkle generation characteristic parameters, and determining to adjust expansion temperature or expansion pressure of the to-be-expanded sleeve according to a difference value; determining whether thermal stability of the to-be-expanded sleeve sample in the expansion process is qualified based on a thermal distribution value of the wrinkle area, and determining to adjust a hot air blowing speed of the to-be-expanded sleeve according to a relative difference; determining whether expansion stability of the to-be-expanded sleeve sample is up to standard based on a wrinkle resilience coefficient, and determining to adjust an expansion time of the to-be-expanded sleeve according to a ratio; and obtaining a target heat-shrinkable sleeve under the condition that the to-be-expanded sleeve does not appear wrinkles in the expansion process. The present application improves manufacturing efficiency of the heat-shrinkable sleeve.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sleeve manufacturing, in particular to a manufacturing method of heat-shrinkable sleeve. BACKGROUND

[0002] The heat-shrinkable sleeve is a kind of high polymer material product that can shrink radially after being heated, and is widely used in wire harness insulation protection, sealing, corrosion prevention and identification in the fields of power, communication, automobile, aerospace, etc. The expansion process is the core link to determine the final size, performance and quality of the heat-shrinkable sleeve. In this process, the crosslinked base pipe is heated to an elastic state and is radially expanded by applying internal pressure, and then is cooled and shaped to obtain heat-shrinkable performance. However, in the expansion process, due to various complex factors such as uneven heating of the material and unbalanced internal stress distribution, the pipe wall is prone to buckling instability and wrinkle. The existence of these wrinkles directly affects the appearance quality and size uniformity of the product, resulting in uneven wall thickness. As stress concentration points, wrinkles can significantly degrade the mechanical strength and long-term service life of the sleeve. Currently, the control of the expansion process generally relies on the experience of the operator, and it is impossible to quantitatively and accurately evaluate the wrinkles and to realize real-time quality monitoring during the production process. When quality problems are found, a large number of unqualified products have usually been produced, resulting in waste of raw materials and energy.

[0003] Chinese patent application publication No. CN112391037A discloses a preparation method of a PET sleeve material for easy-shrinking battery and capacitor, which comprises the following components and their mass percentages: PET 30%-60%, PETG 25%-45%, PBT 7%-12%, SEBS 3%-8%, antioxidant 0.1%-3%, chain extender 0.1%-2%, and the sum of the mass percentages of the above components is 100%. The PET heat-shrinkable sleeve material using the technical solution of the present application has excellent mechanical strength and toughness. The most outstanding feature is that it can shrink perfectly very quickly during the shrinking process, especially when shrinking on an imported battery automatic sleeve machine, there are very few appearance wrinkles, and it meets the requirement of running speed of more than 200 per minute, which is significantly better than the general PET heat-shrinkable sleeve used on ordinary capacitors and domestic battery sleeve machines.

[0004] However, the existing technology has the following problems: relying on a specific material formula to make the material itself more wrinkle-resistant cannot solve the wrinkles caused by improper parameter setting or disturbance during the expansion process, thereby leading to low manufacturing efficiency of the heat-shrinkable sleeve. SUMMARY

[0005] To this end, the present application provides a method for manufacturing heat-shrinkable sleeves to overcome the problem of low manufacturing efficiency of heat-shrinkable sleeves in the prior art, which relies on a specific material formula to make the material itself more wrinkle-resistant, and cannot solve the wrinkles caused by improper parameter settings or disturbances during the expansion process.

[0006] To achieve the above-mentioned purpose, the present application provides a method for manufacturing heat-shrinkable sleeves, comprising:

[0007] After heating the material to a preset temperature, extruding and forming and irradiating cross-linking to obtain a sample of a sleeve to be expanded;

[0008] Using an expansion device to expand the sample of the sleeve to be expanded under preset expansion parameters, and using an image acquisition device to obtain real-time surface images of the sample of the sleeve to be expanded during the expansion process;

[0009] Based on the surface images, a wrinkle state evaluation value is determined to determine whether the sample of the sleeve to be expanded has wrinkles during the expansion process;

[0010] Extracting wrinkle features of the wrinkle region of the sample of the sleeve to be expanded during the expansion process, determining a wrinkle generation characterization parameter based on the wrinkle features, determining whether the expansion uniformity of the sample of the sleeve to be expanded meets the standard, and adjusting the expansion temperature or expansion pressure of the sleeve to be expanded according to the difference between the wrinkle generation characterization parameter and the preset wrinkle generation characterization parameter;

[0011] Obtaining an infrared image of the wrinkle region, determining a wrinkle region heat distribution value based on the infrared image and the wrinkle features, determining whether the thermal stability of the sample of the sleeve to be expanded during the expansion process is qualified, and adjusting the hot air blowing speed of the sleeve to be expanded according to the relative difference between the wrinkle region heat distribution value and the preset wrinkle region heat distribution value;

[0012] Determining a wrinkle rebound coefficient based on the wrinkle features of the sample of the sleeve to be expanded and the sample of the sleeve during the expansion process to determine whether the expansion stability of the sample of the sleeve to be expanded meets the standard, and adjusting the expansion time of the sleeve to be expanded according to the ratio of the preset wrinkle rebound coefficient to the wrinkle rebound coefficient;

[0013] In the case where it is determined that the sleeve to be expanded does not have wrinkles during the expansion process, a target heat-shrinkable sleeve is obtained.

[0014] Further, the occurrence of wrinkles in the sample of the sleeve to be expanded during the expansion process is determined based on the comparison result that the wrinkle state evaluation value is greater than the preset wrinkle state evaluation value.

[0015] The wrinkle state evaluation value is determined according to the actual length of the edge contour, the straight line distance between the two endpoints of the contour, the number of edges, and the gradient amplitude.

[0016] Further, the expansion uniformity of the sample of the pipe to be expanded is determined to be substandard based on a comparison result that a wrinkle generation characteristic parameter is greater than a preset wrinkle generation characteristic parameter, wherein,

[0017] The wrinkle generation characteristic parameter is determined according to a total area of a wrinkle region, a total area of a pipe surface, and a wrinkle depth.

[0018] Further, the process of adjusting the expansion temperature of the pipe to be expanded includes:

[0019] A difference between the wrinkle generation characteristic parameter of the sample of the pipe to be expanded under the condition of the expansion uniformity being substandard and the preset wrinkle generation characteristic parameter is calculated.

[0020] An increase in the expansion temperature is determined based on a comparison result that the difference is less than or equal to a preset difference.

[0021] The increased expansion temperature is determined according to the expansion temperature and a preset expansion temperature adjustment coefficient.

[0022] Further, the process of adjusting the expansion pressure of the pipe to be expanded includes:

[0023] A difference between the wrinkle generation characteristic parameter of the sample of the pipe to be expanded under the condition of the expansion uniformity being substandard and the preset wrinkle generation characteristic parameter is calculated.

[0024] An increase in the expansion pressure is determined based on a comparison result that the difference is greater than a preset difference.

[0025] The increased expansion pressure is determined according to the expansion pressure and a preset expansion pressure adjustment coefficient.

[0026] Further, the heat stability of the sample of the pipe to be expanded during the expansion process is determined to be unqualified based on a comparison result that a wrinkle region heat distribution value is greater than a preset wrinkle region heat distribution value, wherein,

[0027] The wrinkle region heat distribution value is determined according to a maximum temperature, a minimum temperature, an average temperature of the wrinkle region, and a depth average value of the wrinkle region.

[0028] Further, the process of adjusting the hot air blowing speed of the pipe to be expanded includes:

[0029] A relative difference between the wrinkle region heat distribution value of the sample of the pipe to be expanded under the condition of the heat stability during the expansion process being unqualified and the preset wrinkle region heat distribution value is calculated.

[0030] An increase in the hot air blowing speed by a first preset blowing speed adjustment coefficient is determined based on a comparison result that the relative difference is less than or equal to a preset relative difference.

[0031] determine to increase the hot air blowing speed by a second preset blowing speed adjustment coefficient based on the comparison result that the relative difference is greater than a preset relative difference.

[0032] Further, the expansion stability of the to-be-expanded sleeve sample is determined to be substandard based on a comparison result that the wrinkle rebound coefficient is greater than a preset wrinkle rebound coefficient.

[0033] Further, the wrinkle rebound coefficient is the ratio of the absolute value of the difference between the number of all wrinkle profiles of the expanded sleeve sample and the number of the wrinkle of the sleeve sample in the expansion process to the number of the wrinkle of the sleeve sample in the expansion process.

[0034] Further, the process of adjusting the expansion time of the to-be-expanded sleeve comprises:

[0035] calculating the ratio of the preset wrinkle rebound coefficient to the wrinkle rebound coefficient under the condition that the expansion stability of the to-be-expanded sleeve sample is substandard;

[0036] determining to increase the expansion time by a first preset expansion time adjustment coefficient based on a comparison result that the ratio is less than or equal to a preset ratio;

[0037] determining to increase the expansion time by a second preset expansion time adjustment coefficient based on a comparison result that the ratio is greater than the preset ratio.

[0038] Compared with the prior art, the beneficial effects of the present application are that the present application determines whether the to-be-expanded sleeve sample appears wrinkle in the expansion process through the wrinkle state evaluation value, determines whether the expansion uniformity of the to-be-expanded sleeve sample is up to standard according to the wrinkle generation characteristic parameter when the wrinkle exists, adjusts the expansion temperature or the expansion pressure of the next batch of to-be-expanded sleeve when the expansion uniformity is substandard, determines whether the thermal stability of the to-be-expanded sleeve sample in the expansion process is qualified according to the wrinkle area heat distribution value, adjusts the hot air blowing speed of the to-be-expanded sleeve when the thermal stability is unqualified, determines whether the expansion stability of the to-be-expanded sleeve sample is up to standard according to the wrinkle rebound coefficient, adjusts the expansion time of the to-be-expanded sleeve when the expansion stability is substandard, so that the process parameters and the material characteristics are matched in real time, the precision of the expansion process of the heat-shrinkable sleeve is improved, the wrinkle generation characteristic parameter quantifies the uniformity of the expansion process, and thus the manufacturing efficiency of the heat-shrinkable sleeve is improved.

[0039] Further, the present application determines whether the to-be-expanded sleeve sample appears wrinkle in the expansion process through the wrinkle state evaluation value, improves the detection accuracy of the micro-wrinkle, reduces the missed detection rate, quantifies the coverage range of the wrinkle according to the wrinkle generation characteristic parameter, avoids the uneven shrinkage caused by local dense wrinkle and prevents the sealing failure caused by deep wrinkle, reduces the circumferential shrinkage rate deviation of the heat-shrinkable sleeve, and thus the manufacturing efficiency of the heat-shrinkable sleeve is improved.

[0040] Further, the present application judges the thermal stability of the sample of the to-be-expanded sleeve in the expansion process through the wrinkle area heat distribution value, dynamically increases the hot air blowing speed when the thermal stability is unqualified, and the temperature distribution coefficient reflects the temperature uniformity of the wrinkle area, so that the molecular chain rupture caused by local overheating is avoided, the form coefficient combines the spatial distribution and severity of the wrinkle, the local high temperature caused by poor heat dissipation of the deep wrinkle is prevented, and thus the molecular chain degradation caused by local overheating or the insufficient crosslinking caused by insufficient heat is avoided, the precise hot air blowing regulation can inhibit the thermal stress concentration caused by uneven temperature in the expansion process, and the sleeve surface roughness value is reduced.

[0041] Further, the present application judges the thermal stability of the sample of the to-be-expanded sleeve in the expansion process through the wrinkle area heat distribution value, dynamically increases the hot air blowing speed when the thermal stability is unqualified, and the temperature distribution coefficient reflects the temperature uniformity of the wrinkle area, so that the molecular chain rupture caused by local overheating is avoided, the form coefficient combines the spatial distribution and severity of the wrinkle, the local high temperature caused by poor heat dissipation of the deep wrinkle is prevented, and thus the molecular chain degradation caused by local overheating or the insufficient crosslinking caused by insufficient heat is avoided, the precise hot air blowing regulation can inhibit the thermal stress concentration caused by uneven temperature in the expansion process, and the sleeve surface roughness value is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The flow chart of the manufacturing method of the heat-shrinkable sleeve of the embodiment of the present application is shown in the figure.

[0043] Figure 2 The flow chart of the method for determining whether the sample of the to-be-expanded sleeve appears wrinkles in the expansion process is shown in the figure.

[0044] Figure 3 The flow chart of the method for determining whether the expansion uniformity of the sample of the to-be-expanded sleeve is qualified is shown in the figure.

[0045] Figure 4 The flow chart of the method for determining whether the thermal stability of the sample of the to-be-expanded sleeve in the expansion process is qualified is shown in the figure. DETAILED DESCRIPTION

[0046] In order to make the purpose and advantages of the present application more clear and explicit, the present application is further described below in combination with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0047] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0048] It should be noted that the data in the embodiment are obtained by comprehensive analysis and evaluation of historical detection data and corresponding historical detection results in the three months before the detection. Those skilled in the art can understand that the determination method of the present application for a single parameter can be to select the value with the highest proportion as the preset standard parameter according to the data distribution, to use weighted summation to obtain the value as the preset standard parameter, to substitute each historical data into a specific formula and to obtain the value by using the formula as the preset standard parameter, or other selection methods, as long as the present application can clearly define different specific situations in the single determination process by the obtained value.

[0049] Referring to FIG. 1, a flowchart of a manufacturing method of a heat-shrinkable sleeve according to an embodiment of the present application is shown. Figure 1

[0050] The manufacturing method of the heat-shrinkable sleeve according to an embodiment of the present application comprises the following steps.

[0051] In step S1, the material is heated to a preset temperature, extruded and formed, and irradiated and cross-linked to obtain a to-be-expanded sleeve sample.

[0052] In step S2, the to-be-expanded sleeve sample is expanded under preset expansion parameters by using an expansion device, and a surface image of the to-be-expanded sleeve sample in the expansion process is obtained in real time by using an image acquisition device.

[0053] In step S3, a wrinkle state evaluation value is determined based on the surface image to determine whether the to-be-expanded sleeve sample appears wrinkles in the expansion process.

[0054] In step S4, a wrinkle feature of a wrinkle region of the to-be-expanded sleeve sample in the expansion process is extracted, a wrinkle generation characteristic parameter is determined based on the wrinkle feature to determine whether the expansion uniformity of the to-be-expanded sleeve sample meets the standard, and the expansion temperature or expansion pressure of the to-be-expanded sleeve is adjusted according to the difference between the wrinkle generation characteristic parameter and a preset wrinkle generation characteristic parameter.

[0055] In step S5, an infrared image of the wrinkle region is obtained, a wrinkle region heat distribution value is determined based on the infrared image and the wrinkle feature to determine whether the thermal stability of the to-be-expanded sleeve sample in the expansion process is qualified, and the hot air blowing speed of the to-be-expanded sleeve is adjusted according to the relative difference between the wrinkle region heat distribution value and a preset wrinkle region heat distribution value.

[0056] In step S6, a wrinkle rebound coefficient is determined based on the wrinkle features of the sleeve sample after completion of expansion and the sleeve sample in the expansion process to determine whether the expansion stability of the to-be-expanded sleeve sample meets the standard, and the expansion time of the to-be-expanded sleeve is adjusted according to the ratio of the preset wrinkle rebound coefficient to the wrinkle rebound coefficient.

[0057] ​Step S7, obtaining the target heat-shrinkable sleeve under the condition that no wrinkles of the to-be-expanded sleeve occur in the expansion process.

[0058] Specifically, the present application determines whether wrinkles occur in the to-be-expanded sleeve sample during the expansion process through the wrinkle state evaluation value, and when wrinkles exist, determines whether the expansion uniformity of the to-be-expanded sleeve sample meets the standard according to the wrinkle generation characteristic parameter, adjusts the expansion temperature or expansion pressure of the next batch of to-be-expanded sleeve when it does not meet the standard, determines whether the thermal stability of the to-be-expanded sleeve sample in the expansion process is qualified according to the wrinkle area thermal distribution value, adjusts the hot air blowing speed of the to-be-expanded sleeve when it is unqualified, determines whether the expansion stability of the to-be-expanded sleeve sample meets the standard according to the wrinkle resilience coefficient, and adjusts the expansion time of the to-be-expanded sleeve when it does not meet the standard, so that the process parameters and material characteristics are matched in real time, the accuracy of the heat-shrinkable sleeve expansion process is improved, the wrinkle generation characteristic parameter quantifies the uniformity of the expansion process, and therefore the manufacturing efficiency of the heat-shrinkable sleeve is improved.

[0059] In the embodiment of the present application, the material is a polyolefin, the preset temperature is 180-220 DEG C, preferably 200 DEG C, the irradiation crosslinking is performed by an electron accelerator, the irradiation dose is 10-30 kGy, preferably 20 kGy, and the material is not limited, and is selected according to the actual application scene.

[0060] Specifically, the present application adopts an expansion device to expand the to-be-expanded sleeve sample under preset expansion parameters, and an image acquisition device is used to acquire the surface image of the to-be-expanded sleeve sample in the expansion process

[0061] In the embodiment of the present application, the preset expansion parameters include that the expansion temperature is 100-130 DEG C, preferably 115 DEG C, the expansion pressure is 0.1-0.3 MPa, preferably 0.2 MPa, the expansion time is 40-60 s, preferably 50 s, the hot air blowing speed is 5-15 m / s, preferably 10 m / s, and the image acquisition device is an industrial camera.

[0062] Please refer to Figure 2 As shown in the figure, it is a flow chart for determining whether the to-be-expanded sleeve sample has wrinkles in the expansion process.

[0063] Specifically, under the condition that the surface image of the to-be-expanded sleeve sample is obtained, whether the to-be-expanded sleeve sample has wrinkles in the expansion process is determined according to the comparison result of the wrinkle state evaluation value determined according to the surface image and the preset wrinkle state evaluation value.

[0064] When the wrinkle state evaluation value is less than or equal to the preset wrinkle state evaluation value, it is determined that the to-be-expanded sleeve sample does not have wrinkles in the expansion process.

[0065] When the wrinkle state evaluation value is greater than the preset wrinkle state evaluation value, it is determined that the to-be-expanded casing sample has wrinkles during the expansion process.

[0066] In the embodiment of the present application, the preset wrinkle state evaluation value is in the range of [0.05, 0.15], preferably 0.1, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to actual needs.

[0067] In the embodiment of the present application, the process of obtaining the wrinkle state evaluation value is as follows: after the surface image is subjected to grayscale processing and denoising, a grayscale image is obtained; the inter-class variance of the grayscale image is calculated using the OTSU threshold segmentation algorithm, the grayscale value at which the variance is maximum is selected as the threshold value, the region with a pixel value greater than or equal to the threshold value is marked as the casing region, and the region with a pixel value less than the threshold value is marked as the background region; the profile of the casing region with an edge continuous length greater than or equal to 10 pixels is extracted using the Canny algorithm, and the ratio of the actual length of the edge profile of a plurality of edges to the ratio of the straight line distance between the two endpoints of the profile is summed, denoted as edge irregularity; the gradient amplitude of each pixel of the casing region is calculated by the Sobel operator; the ratio of the standard deviation to the average value of the gradient amplitude of the casing region is denoted as the gray gradient variation coefficient; the wrinkle state evaluation value is the product of the wrinkle state evaluation value and the weight 0.5 plus the product of the gray gradient variation coefficient and the weight 0.5.

[0068] Specifically, the embodiment of the present application marks the region where the to-be-expanded casing sample has wrinkles during the expansion process as a wrinkle region, and extracts the wrinkle characteristics of the wrinkle region, wherein the wrinkle characteristics include the width, depth, number and area of the wrinkles.

[0069] Please refer to Figure 3 As shown in the flowchart of FIG. 1, which is the process of determining whether the expansion uniformity of the to-be-expanded casing sample meets the standard in the embodiment of the present application.

[0070] Specifically, the embodiment of the present application extracts the wrinkle characteristics of the wrinkle region of the to-be-expanded casing sample during the expansion process, and determines whether the expansion uniformity of the to-be-expanded casing sample meets the standard according to the comparison result of the wrinkle generation representation parameter determined according to the wrinkle characteristics and the preset wrinkle generation representation parameter;

[0071] When the wrinkle generation representation parameter is less than or equal to the preset wrinkle generation representation parameter, it is determined that the expansion uniformity of the to-be-expanded casing sample meets the standard;

[0072] When the wrinkle generation representation parameter is greater than the preset wrinkle generation representation parameter, it is determined that the expansion uniformity of the to-be-expanded casing sample does not meet the standard.

[0073] In the embodiment of the present application, the preset wrinkle generation characteristic parameter value range is [0.1, 0.2], preferably 0.15, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to actual needs.

[0074] In the embodiment of the present application, the wrinkle generation characteristic parameter is obtained by obtaining the ratio of the total area of the wrinkle region to the total area of the sleeve surface through image segmentation, denoted as the wrinkle distribution density; the ratio of the standard deviation of the wrinkle depth of all extracted wrinkles to the average value of the wrinkle depth is denoted as the wrinkle distribution depth; the product of the wrinkle distribution density and the weight 0.6 is added to the product of the wrinkle distribution depth and the weight 0.4, denoted as the wrinkle generation characteristic parameter.

[0075] Specifically, under the condition that the expansion uniformity of the to-be-expanded sleeve sample does not meet the standard, the difference between the wrinkle generation characteristic parameter and the preset wrinkle generation characteristic parameter is compared with the preset difference value to determine whether to adjust the expansion temperature or expansion pressure of the to-be-expanded sleeve.

[0076] When the difference is less than or equal to the preset difference value, it is determined that the expansion temperature is increased to the corresponding value by a preset expansion temperature adjustment coefficient 1.1;

[0077] When the difference is greater than the preset difference value, it is determined that the expansion pressure is increased to the corresponding value by a preset expansion pressure adjustment coefficient 1.2.

[0078] The difference is the difference between the wrinkle generation characteristic parameter and the preset wrinkle generation characteristic parameter.

[0079] In the embodiment of the present application, the preset difference value range is [0.05, 0.09], preferably 0.07, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to actual needs.

[0080] In the embodiment of the present application, the increased expansion temperature is the product of the expansion temperature and the preset expansion temperature adjustment coefficient, the preset expansion temperature adjustment coefficient is 1.1, the increased expansion pressure is the product of the expansion pressure and the preset expansion pressure adjustment coefficient, the preset expansion pressure adjustment coefficient is 1.2, in order to ensure that the adjusted expansion temperature and expansion pressure adjustment coefficient meet the actual needs, the adjustment range should not be too large, so the adjustment coefficient is set to control the adjustment range.

[0081] Specifically, the present application determines whether the to-be-expanded sleeve sample is wrinkled in the expansion process by the wrinkle state evaluation value, improves the detection accuracy of the micro-wrinkle, reduces the missed detection rate, quantifies the coverage of the wrinkle according to the wrinkle generation characteristic parameter, avoids the uneven shrinkage caused by the local dense wrinkle and prevents the sealing failure caused by the deep wrinkle, reduces the deviation of the circumferential shrinkage rate of the heat-shrinkable sleeve, and thus improves the manufacturing efficiency of the heat-shrinkable sleeve.

[0082] Referring to Figure 4 As shown in the figure, it is a flow chart for determining whether the heat stability of the to-be-expanded sleeve sample in the expansion process is qualified according to the present application.

[0083] Specifically, the present application determines whether the to-be-expanded sleeve sample is wrinkled in the expansion process by the wrinkle state evaluation value, improves the detection accuracy of the micro-wrinkle, reduces the missed detection rate, quantifies the coverage of the wrinkle according to the wrinkle generation characteristic parameter, avoids the uneven shrinkage caused by the local dense wrinkle and prevents the sealing failure caused by the deep wrinkle, reduces the deviation of the circumferential shrinkage rate of the heat-shrinkable sleeve, and thus improves the manufacturing efficiency of the heat-shrinkable sleeve.

[0084] When the wrinkle region heat distribution value is less than or equal to the preset wrinkle region heat distribution value, it is determined that the heat stability of the to-be-expanded sleeve sample in the expansion process is qualified.

[0085] When the wrinkle region heat distribution value is greater than the preset wrinkle region heat distribution value, it is determined that the heat stability of the to-be-expanded sleeve sample in the expansion process is unqualified.

[0086] In the present application, the preset wrinkle region heat distribution value is in the range of [0.2, 0.3], preferably 0.25, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to the actual needs.

[0087] In the present application, the process of obtaining the wrinkle region heat distribution value is as follows: temperature calibration is performed on the infrared image, the pixel value is converted into the actual temperature value, the highest temperature, the lowest temperature and the average temperature of the wrinkle region are extracted; the ratio of the difference between the highest temperature and the lowest temperature to the average temperature is denoted as the wrinkle temperature distribution coefficient; the ratio of the average depth of the wrinkle region to the maximum wrinkle depth threshold multiplied by the weight 0.6 plus the product of the wrinkle distribution density and the weight 0.4 is denoted as the wrinkle shape coefficient, wherein the maximum wrinkle depth threshold is set to 0.3 mm; the product of the wrinkle temperature distribution coefficient and the weight 0.7 plus the product of the wrinkle shape coefficient and the weight 0.3 is denoted as the wrinkle region heat distribution value.

[0088] Specifically, under the condition that the heat stability of the to-be-expanded sleeve sample in the expansion process is unqualified, the present application adjusts the hot air blowing speed of the to-be-expanded sleeve according to the comparison result of the relative difference between the wrinkle region heat distribution value and the preset wrinkle region heat distribution value and the preset relative difference.

[0089] When the relative difference is less than or equal to the preset relative difference, it is determined that the hot air blowing speed is increased to a corresponding value by a first preset blowing speed adjustment coefficient 1.15;

[0090] When the relative difference is greater than the preset relative difference, it is determined that the hot air blowing speed is increased to a corresponding value by a second preset blowing speed adjustment coefficient 1.25;

[0091] The relative difference is the relative difference between the wrinkle area heat distribution value and the preset wrinkle area heat distribution value.

[0092] In the embodiment of the application, the preset relative difference is in the range of [0.4, 0.5], preferably 0.45, but the above values are not limited thereto, and a person skilled in the art can adjust the values according to actual needs.

[0093] In the embodiment of the application, the increased hot air blowing speed is the product of the hot air blowing speed and the preset blowing speed adjustment coefficient, the preset blowing speed adjustment coefficient includes the first preset blowing speed adjustment coefficient with a value of 1.15 and the second preset blowing speed adjustment coefficient with a value of 1.25, in order to ensure that the adjusted hot air blowing speed meets the actual needs, the adjustment range should not be too large, so the adjustment coefficient is set to control the adjustment range.

[0094] Specifically, the application judges the thermal stability of the to-be-expanded sleeve sample in the expansion process through the wrinkle area heat distribution value, dynamically increases the hot air blowing speed when the thermal stability is unqualified, the temperature distribution coefficient reflects the temperature uniformity of the wrinkle area, avoids the molecular chain rupture caused by local overheating, the form coefficient combines the spatial distribution and severity of the wrinkle, prevents local high temperature caused by poor heat dissipation of deep wrinkles, thereby avoiding the molecular chain degradation caused by local overheating or insufficient crosslinking caused by insufficient heat, and the precise hot air blowing regulation can inhibit the thermal stress concentration caused by uneven temperature in the expansion process, and reduces the sleeve surface roughness value.

[0095] Specifically, the application determines whether the expansion stability of the to-be-expanded sleeve sample meets the standard according to the comparison result of the wrinkle rebound coefficient determined according to the final wrinkle of the expanded sleeve sample and the process wrinkle in the expansion process and the preset wrinkle rebound coefficient;

[0096] When the wrinkle rebound coefficient is less than or equal to the preset wrinkle rebound coefficient, it is determined that the expansion stability of the to-be-expanded sleeve sample meets the standard;

[0097] When the wrinkle rebound coefficient is greater than the preset wrinkle rebound coefficient, it is determined that the expansion stability of the to-be-expanded sleeve sample does not meet the standard.

[0098] In the embodiment of the present application, the preset wrinkle resilience coefficient value range is [0.13, 0.23], preferably 0.17, but the above-mentioned value is not limited thereto, and the person skilled in the art can also adjust the value according to actual needs.

[0099] In the embodiment of the present application, the process of obtaining the wrinkle resilience coefficient is the ratio of the absolute value of the difference between the number of all wrinkle profiles of the expanded sleeve sample and the number of the sleeve sample wrinkle in the expansion process to the number of the sleeve sample wrinkle in the expansion process.

[0100] Specifically, under the condition that the expansion stability of the to-be-expanded sleeve sample is not up to standard, the present application adjusts the expansion time of the to-be-expanded sleeve according to the comparison result of the ratio of the preset wrinkle resilience coefficient to the wrinkle resilience coefficient and the preset ratio;

[0101] When the ratio is less than or equal to the preset ratio, the expansion time of the to-be-expanded sleeve is increased to the corresponding value by a first preset expansion time adjustment coefficient 1.05;

[0102] When the ratio is greater than the preset ratio, the expansion time of the to-be-expanded sleeve is increased to the corresponding value by a second preset expansion time adjustment coefficient 1.35.

[0103] The ratio is the ratio of the preset wrinkle resilience coefficient to the wrinkle resilience coefficient.

[0104] In the embodiment of the present application, the preset ratio value range is [0.6, 0.7], preferably 0.65, but the above-mentioned value is not limited thereto, and the person skilled in the art can also adjust the value according to actual needs.

[0105] In the embodiment of the present application, the increased expansion time is the product of the expansion time and the preset expansion time adjustment coefficient, the preset expansion time adjustment coefficient includes the first preset expansion time adjustment coefficient with a value of 1.05 and the second preset expansion time adjustment coefficient with a value of 1.35, in order to ensure that the adjusted expansion time meets the actual needs, the adjustment range should not be too large, so the adjustment coefficient is set to control the adjustment range.

[0106] Specifically, the present application judges the expansion stability by comparing the difference between the number of wrinkles of the expanded sleeve and the number of wrinkles of the sleeve in the expansion process, and dynamically extends the expansion time when the stability is not up to standard, and evaluates the expansion stability according to the wrinkle resilience coefficient, which improves the control precision, ensures the size consistency of the heat-shrinkable sleeve, and precisely extends the expansion time, which can promote the full relaxation of molecular chains, reduce the internal stress caused by resilience, reduce the internal diameter deviation of the sleeve after shrinkage, and improve the adhesion to the protected member.

[0107] The technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical schemes after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A method for manufacturing a heat shrink tubing, characterized in that, include: The material is heated to a preset temperature, extruded and then cross-linked by irradiation to obtain the tube sample to be expanded; The expansion device is used to expand the sleeve sample under preset expansion parameters, and the surface image of the sleeve sample to be expanded is acquired in real time through an image acquisition device. Based on the surface image, a wrinkle status evaluation value is determined to determine whether wrinkles appear in the sleeve sample to be expanded during the expansion process; The determination of wrinkles appearing in the cannula sample during expansion is based on a comparison of the wrinkle state evaluation value with a preset wrinkle state evaluation value. The wrinkle state evaluation value is determined based on the actual length of the edge contour, the straight-line distance between the two ends of the contour, the number of edges, and the gradient magnitude. Extract the wrinkle features of the wrinkled area of ​​the folded area of ​​the folded tube sample during the expansion process, determine the wrinkle generation characterization parameters based on the wrinkle features, determine whether the expansion uniformity of the folded tube sample meets the standard, and determine the expansion temperature or expansion pressure of the folded tube to be expanded based on the difference between the wrinkle generation characterization parameters and the preset wrinkle generation characterization parameters. Infrared images of the folded region are acquired, and the heat distribution value of the folded region is determined based on the infrared images and the folded features to determine whether the thermal stability of the sleeve sample to be expanded is qualified during the expansion process. The hot air blowing speed of the sleeve to be expanded is adjusted according to the relative difference between the heat distribution value of the folded region and the preset heat distribution value of the folded region. The failure of the expansion stability of the tube sample to be expanded to meet the standard is determined based on the comparison result that the wrinkle rebound coefficient is greater than the preset wrinkle rebound coefficient. The wrinkle rebound coefficient is determined based on the wrinkle characteristics of the completed expansion tube sample and the tube sample during the expansion process, so as to determine whether the expansion stability of the tube sample to be expanded meets the standard, and the expansion time of the tube to be expanded is adjusted according to the ratio of the preset wrinkle rebound coefficient to the wrinkle rebound coefficient. Wherein, the wrinkle resilience coefficient is the ratio of the absolute value of the difference between the total number of wrinkles in the expanded sleeve sample and the number of wrinkles in the sleeve sample during the expansion process to the total number of wrinkles in the sleeve sample during the expansion process. The process of adjusting the expansion time of the sleeve to be expanded includes: Calculate the ratio of the preset wrinkle springback coefficient to the wrinkle springback coefficient under the condition that the expansion stability of the cannula sample does not meet the standard. Based on the comparison results where the ratio is less than or equal to a preset ratio, the expansion time is increased by a first preset expansion time adjustment coefficient. Based on the comparison results where the ratio is greater than a preset ratio, the expansion time is increased by a second preset expansion time adjustment coefficient. The target heat shrink tubing is obtained after confirming that no wrinkles appear in the tubing to be expanded during the expansion process.

2. The method for manufacturing heat shrink tubing according to claim 1, characterized in that, The failure of the expansion uniformity of the cannula sample to be expanded was determined based on the comparison results of the wrinkle generation characterization parameter being greater than the preset wrinkle generation characterization parameter. The wrinkle generation characterization parameters are determined based on the total area of ​​the wrinkled region, the total area of ​​the casing surface, and the wrinkle depth.

3. The method for manufacturing heat shrink tubing according to claim 2, characterized in that, The process of adjusting the expansion temperature of the sleeve to be expanded includes: Calculate the difference between the wrinkle generation characterization parameter and the preset wrinkle generation characterization parameter under the condition that the expansion uniformity of the tube sample is not up to standard. The expansion temperature is increased based on the comparison results where the difference is less than or equal to a preset difference. The increased expansion temperature is determined based on the expansion temperature and the preset expansion temperature adjustment coefficient.

4. The method for manufacturing a heat shrink tubing according to claim 3, characterized in that, The process of adjusting the expansion pressure of the sleeve to be expanded includes: Calculate the difference between the wrinkle generation characterization parameter and the preset wrinkle generation characterization parameter under the condition that the expansion uniformity of the tube sample is not up to standard. Based on the comparison results where the difference is greater than a preset difference, the expansion pressure is increased; The increased expansion pressure is determined based on the expansion pressure and the preset expansion pressure adjustment coefficient.

5. The method for manufacturing a heat shrink tubing according to claim 4, characterized in that, The failure of the thermal stability of the tube sample to be expanded during the expansion process was determined based on a comparison result showing that the thermal distribution value of the wrinkled region was greater than the preset thermal distribution value of the wrinkled region. The heat distribution value of the folded region is determined based on the highest temperature, lowest temperature, average temperature of the folded region, and the average depth of the folded region.

6. The method for manufacturing a heat shrink tubing according to claim 5, characterized in that, The process of adjusting the hot air blowing speed of the sleeve to be expanded includes: Calculate the relative difference between the thermal distribution value of the wrinkled region and the preset thermal distribution value of the wrinkled region of the sample to be expanded under the condition of unqualified thermal stability during the expansion process. Based on the comparison results where the relative difference is less than or equal to the preset relative difference, the hot air blowing speed is increased by the first preset blowing speed adjustment coefficient. Based on the comparison result that the relative difference is greater than the preset relative difference, the hot air blowing speed is increased by the second preset blowing speed adjustment coefficient.

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