A forming method and system for large creepage distance transformer bushings

Abstract

The present invention relates to the technical field of transformer bushing processing and forming, and particularly relates to a forming method and system for a large creepage distance transformer bushing, including: after heating the material, injecting the material into a mold under a preset injection pressure and a preset injection temperature, maintaining pressure and cooling to obtain a target bushing; when it is determined that the injection of the bushing does not meet the preset standard according to the surface density characterization value, obtaining a bubble evaluation value by the bubble diameter at the root of the petticoat and the number of bubbles at the top of the petticoat, and obtaining a thickness distribution characterization value by the thickness at the edge of the top of the petticoat; when it is determined that the injection of the bushing does not meet the preset standard, re-determining whether the injection of the bushing meets the preset standard according to the bubble evaluation value of the petticoat, or determining the reason for the injection not meeting the preset standard according to the thickness distribution characterization value of the petticoat, thereby improving the forming accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of transformer bushing processing and forming, and in particular to a large creepage distance transformer bushing forming method and system. Background Art

[0002] As a key insulating component of high-voltage equipment, the core function of transformer bushing is to ensure reliable insulation between live conductors and grounded shells, and withstand complex mechanical loads and environmental stresses. The insulation performance of the bushing is mainly determined by its external shed structure, and the creepage distance of the shed directly affects the arc resistance of the equipment under dirty, humid and other harsh working conditions.

[0003] Creepage distance, or creepage distance, refers to the shortest distance from one conductor to another along the surface of the insulator between them. Creepage distance is an important performance parameter of transformer bushing. Usually, the creepage distance is extended by increasing the number of sheds. Although sheds increase the creepage distance at both ends of the bushing, and each additional shed can increase the creepage distance, the shed spacing needs to be maintained within a reasonable range to avoid electric field distortion between sheds, which causes the axial length of the bushing to increase linearly with the number of sheds.

[0004] Excessive length not only increases the difficulty of transportation and installation, but also significantly increases material costs; In order to ensure the structural strength during injection molding, traditional sheds often adopt a uniformly thickened design, but the edges of overly thick sheds are prone to cause local discharge under strong electric fields, hinder the heat dissipation of the bushing, and accelerate insulation aging.

[0005] Chinese patent application publication number: CN119170360A, discloses an integrated shed structure casing and its production method, which relates to the technical field of glass fiber reinforced plastic dry type casing, firstly, glass fiber and conductive tape are mixed and wound to form a glass fiber reinforced plastic core, and then the glass fiber reinforced plastic core is vulcanized to obtain a vulcanized casing, and then an integrated vulcanization technology is used to vulcanize the vulcanized area of ​​the vulcanized casing to form an outer insulating shed. The structural casing obtained by the above production method is not easy for moisture and foreign matter to penetrate between the outer insulating shed and the vulcanized casing, and if the insulating shed is damaged in subsequent use, the damaged shed can be repaired in a constant temperature heating environment after pre-treatment of the damaged shed. Compared with the traditional technology in which multiple sheds are bonded together, it is not necessary to repair the shed as a whole, and only the damaged part needs to be vulcanized.

[0006] It can be seen that the above technical solution does not consider the influence of the large creepage distance shed and the thin-wall structure of the shed on the preparation process, and does not consider the influence of the density difference between the root and the top of the shed, the bubbles on the surface of the shed and the thickness of the edge of the shed on the product quality, which leads to the problem of low molding accuracy of the casing. Summary of the invention

[0007] To this end, the present invention provides a method and system for forming a large creepage distance transformer bushing, which are used to overcome the problems in the prior art that the influence of the thin-walled structure of the large creepage distance umbrella skirts on the manufacturing process is not considered, the influence of the density difference between the root and the top of the umbrella skirt, the surface bubbles of the umbrella skirt, and the thickness of the edge of the umbrella skirt on the product quality is not considered, resulting in low forming accuracy of the bushing.

[0008] To achieve the above object, on the one hand, the present invention provides a method for forming a large creepage distance transformer bushing, including:

[0009] After heating the material, injecting the material into the mold under a preset injection pressure and a preset injection temperature, holding the pressure and cooling to obtain a target bushing;

[0010] Obtaining the densities of several umbrella skirts of the target bushing, and obtaining a surface density characterization value of the umbrella skirt;

[0011] When it is determined that the injection molding of the bushing does not meet the preset standard according to the surface density characterization value, obtaining a bubble evaluation value by the bubble diameter at the root of the umbrella skirt and the number of bubbles at the top of the umbrella skirt, and obtaining a thickness distribution characterization value by the thickness of the edge at the top of the umbrella skirt;

[0012] When it is determined that the injection molding of the bushing does not meet the preset standard, re-determining whether the injection molding of the bushing meets the preset standard according to the bubble evaluation value of the umbrella skirt, or determining the reason for the non-compliance of the injection molding with the preset standard according to the thickness distribution characterization value of the umbrella skirt, where the reasons include poor mold exhaust or poor fluidity of the material.

[0013] Further, the target bushing includes an insulating tube and several umbrella skirts uniformly arranged along the axial direction of the insulating tube. Among them, the end connecting the umbrella skirt to the insulating tube is denoted as the root of the umbrella skirt, and the end of the umbrella skirt away from the insulating tube is denoted as the top of the umbrella skirt.

[0014] Further, it is determined that the injection molding of the bushing does not meet the preset standard in response to the surface density characterization value of the umbrella skirt being greater than or equal to the first preset surface density characterization value.

[0015] Further, the process of obtaining the surface density characterization value includes:

[0016] Measuring the densities of several measurement points in the first annular region and the second annular region respectively to obtain the density of the first annular region and the density of the second annular region, and obtaining the difference between the density of the first annular region and the density of the second annular region, denoted as the regional density difference;

[0017] Obtaining the regional density differences of several umbrella skirts;

[0018] Calculating the arithmetic mean of the regional density differences of all umbrella skirts, denoted as the surface density characterization value;

[0019] Among them, the first annular region is located at the root where the umbrella skirt is connected to the insulating tube, the second annular region is located at the top of the umbrella skirt far from the insulating tube, the ring width of the first annular region is greater than that of the second annular region, and the number of measurement points of the first annular region is equal to that of the second annular region.

[0020] Further, under the condition that the surface density characterization value is greater than or equal to the first preset surface density characterization value and less than the second preset surface density characterization value, the injection molding of the casing is secondarily determined whether it meets the preset standard according to the bubble evaluation value of the umbrella skirt, and, under the condition that the surface density characterization value is greater than or equal to the second preset surface density characterization value, the reason for the injection molding not meeting the preset standard is determined according to the thickness distribution characterization value of the umbrella skirt.

[0021] Further, the process of secondarily determining that the injection molding of the casing does not meet the preset standard according to the bubble evaluation value of the umbrella skirt includes:

[0022] Comparing the bubble evaluation value with the first preset bubble threshold and the second preset bubble threshold respectively;

[0023] If the bubble evaluation value is greater than or equal to the first preset bubble threshold and less than the second preset bubble threshold, it is determined that the injection molding of the casing does not meet the preset standard, and the injection pressure is increased according to the difference between the bubble evaluation value and the first preset bubble threshold;

[0024] If the bubble evaluation value is greater than or equal to the second preset bubble threshold, it is determined that the injection molding of the casing does not meet the preset standard, and the injection molding is stopped for maintenance;

[0025] The bubble evaluation value is jointly determined by the bubble diameter at the root of the umbrella skirt and the number of bubbles at the top of the umbrella skirt.

[0026] Further, there are several adjustment methods for increasing the injection pressure, and each adjustment method has a different increase range for the injection pressure.

[0027] Further, determining the reason for the injection molding not meeting the preset standard according to the thickness distribution characterization value at the top of the umbrella skirt includes that the mold exhaust is poor and a warning is issued, or, the fluidity of the material is poor and the injection temperature of the material is increased according to the difference between the thickness distribution characterization value and the preset thickness distribution characterization value;

[0028] The thickness distribution characterization value is determined by the thickness of the edge at the top of the umbrella skirt.

[0029] Further, the increase range of the injection temperature of the material is positively correlated with the thickness difference, where the thickness difference is the difference between the thickness distribution characterization value and the preset thickness distribution characterization value.

[0030] On the other hand, the present invention provides a forming system applicable to a forming method for a large creepage transformer bushing, including an injection molding module, which includes an injection unit for injecting materials, a mold unit for forming the materials, and a cooling unit for cooling the target bushing;

[0031] A data acquisition module, which is connected to the injection molding module, includes a density acquisition unit for obtaining the density of the umbrella skirt, an image acquisition unit for obtaining the surface bubbles of the umbrella skirt, and a thickness acquisition unit for obtaining the thickness of the umbrella skirt;

[0032] An injection control module, which is respectively connected to the injection molding module and the data acquisition module, is used to, when it is determined that the injection of the bushing does not meet the preset standard according to the surface density characterization value, re-determine whether the injection of the bushing meets the preset standard according to the bubble evaluation value of the umbrella skirt, or determine the reason why the injection does not meet the preset standard according to the thickness distribution characterization value of the umbrella skirt.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention preliminarily checks the quality of the bushing injection molding by setting the surface density characterization value; when the comparison result is in the intermediate threshold range, a bubble evaluation value is set for secondary inspection, and a composite calculation model of the root bubble diameter and the top bubble quantity is adopted to distinguish repairable defects from serious defects that require shutdown for maintenance when it is determined that the quality of the bushing injection molding does not meet the standard; when the comparison result is in the high threshold range, the problems of poor mold exhaust or poor material fluidity are quickly located through the thickness distribution characterization value; the defect detection dimension is extended from a single detection value to density distribution, bubble morphology, and thickness uniformity, and a multi-dimensional quality evaluation system is constructed, thereby improving the forming accuracy.

[0034] Furthermore, the present invention sets measurement areas with equal area but different ring widths, fully adapts to the geometric characteristics of the umbrella skirt, obtains the surface density characterization value, and determines the preparation effect of the bushing according to the surface density characterization value, effectively capturing the density abnormality of the umbrella skirt and making corresponding adjustments, thereby improving the preparation process accuracy of the bushing.

[0035] Furthermore, the present invention constructs a bubble evaluation value based on a composite parameter model of the root bubble diameter of the umbrella skirt and the spacing of the top bubbles of the umbrella skirt, breaks through the limitations of traditional single bubble size detection, can simultaneously characterize the two defects of material flow front stagnation and poor exhaust, and combines the surface density characterization value with the bubble evaluation value for determination, thereby improving the reliability of the evaluation.

[0036] Furthermore, the present invention provides several adjustment methods for the increase of the injection pressure, and each adjustment method has a different increase amplitude for the injection pressure, thereby realizing precise control of the increase amplitude of the injection pressure.

[0037] Furthermore, when the thickness distribution characterization value is lower than the threshold, the present invention directly associates it with an abnormality in the mold exhaust system and triggers a warning; when the thickness distribution characterization value is higher than the threshold, it is determined that the material fluidity is insufficient, and the temperature compensation program is automatically started, thereby realizing the rapid distinction of the root cause of process abnormalities. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flowchart of the forming method of the large creepage distance transformer bushing according to the embodiment of the present invention;

[0039] Figure 2 It is a flowchart of determining whether the injection molding of the bushing meets the preset standard according to the surface density characterization value in the embodiment of the present invention;

[0040] Figure 3 It is a flowchart of determining the reason why the injection molding does not meet the preset standard in the embodiment of the present invention;

[0041] Figure 4 It is a schematic diagram of the module connection of the forming system applicable to the forming method of the large creepage distance transformer bushing according to the embodiment of the present invention;

[0042] Figure 5 It is a schematic structural diagram of the large creepage distance transformer bushing according to the embodiment of the present invention;

[0043] In the figure, 1 is an insulating tube; 2 is a petticoat. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] The preferred embodiments of the present invention will be 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 invention and do not limit the protection scope of the present invention.

[0046] It should be noted that the data in this embodiment are obtained through comprehensive analysis and evaluation of the historical test data and the corresponding historical test results of the present invention in the three months before this test. Those skilled in the art can understand that the determination method of the present invention for a single above-mentioned parameter can be to select the value with the highest proportion according to the data distribution as the preset standard parameter, use weighted summation to obtain the value as the preset standard parameter, substitute each historical data into a specific formula and use the value obtained by the formula as the preset standard parameter or other selection methods, as long as it satisfies that the method of the present invention can clearly define different specific situations in the single determination process through the obtained value.

[0047] Please refer toFigure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown respectively in the flowchart of the forming method of the large creepage distance transformer bushing according to the embodiment of the present invention; the flowchart of determining whether the injection molding of the bushing meets the preset standard according to the surface density characterization value; the flowchart of determining the reason why the injection molding does not meet the preset standard; the schematic diagram of the module connection of the forming system applicable to the forming method of the large creepage distance transformer bushing and the structural schematic diagram of the large creepage distance transformer bushing according to the embodiment of the present invention.

[0048] On the one hand, the embodiment of the present invention provides a forming method for a large creepage distance transformer bushing, including:

[0049] Step S1, after heating the material, injecting the material into the mold under a preset injection pressure and a preset injection temperature for pressure holding and cooling to obtain a target bushing;

[0050] Step S2, obtaining the density of a plurality of umbrella skirts 2 of the target bushing, and obtaining the surface density characterization value of the umbrella skirts 2;

[0051] Step S3, when it is determined that the injection molding of the bushing does not meet the preset standard according to the surface density characterization value, obtaining a bubble evaluation value by the bubble diameter at the root of the umbrella skirt 2 and the number of bubbles at the top of the umbrella skirt 2 and obtaining a thickness distribution characterization value by the thickness at the edge of the top of the umbrella skirt 2;

[0052] Step S4, when it is determined that the injection molding of the bushing does not meet the preset standard, re-determining whether the injection molding of the bushing meets the preset standard according to the bubble evaluation value of the umbrella skirt 2, or determining the reason why the injection molding does not meet the preset standard according to the thickness distribution characterization value of the umbrella skirt 2, where the reasons include poor mold exhaust or poor fluidity of the material.

[0053] In step S1 of this embodiment, the material is selected as epoxy resin, heated to a molten state at a preset injection temperature of 175 °C, the molten material is injected into the mold cavity under a preset injection pressure of 80 MPa for pressure holding for 30 s, the water cooling system is started, and after cooling the mold cavity temperature, demolding is performed to obtain a target bushing.

[0054] Please refer to Figure 5 As shown, specifically, the target bushing includes an insulating tube 1 and a plurality of umbrella skirts 2 uniformly arranged along the axial direction of the insulating tube. Among them, the end where the umbrella skirt 2 is connected to the insulating tube 1 is denoted as the root of the umbrella skirt 2, and the end of the umbrella skirt 2 away from the insulating tube 1 is denoted as the top of the umbrella skirt 2.

[0055] Specifically, the root of the umbrella skirt 2 refers to the part where the umbrella skirt is directly connected to the insulating tube, which is located at the starting end of the axial length of the umbrella skirt; the top of the umbrella skirt 2 is located at the end of the axial length of the umbrella skirt, and its ring width is smaller than that of the root and has a tapered structure.

[0056] Specifically, it is determined whether the injection molding of the casing meets the preset standard according to the surface density characterization value of the umbrella skirt 2. Among them, if the surface density characterization value is less than the first preset surface density characterization value of 0.08 g / cm 3 , it is determined that the injection molding of the casing meets the preset standard;

[0057] If the surface density characterization value is greater than or equal to the first preset surface density characterization value and less than the second preset surface density characterization value of 0.13 g / cm 3 , it is determined that the injection molding of the casing does not meet the preset standard, and it is further determined whether the injection molding of the casing meets the preset standard according to the bubble evaluation value of the umbrella skirt 2;

[0058] If the surface density characterization value is greater than or equal to the second preset surface density characterization value, it is determined that the injection molding of the casing does not meet the preset standard, and the reason for the non-compliance of the injection molding is determined according to the thickness distribution characterization value of the umbrella skirt 2.

[0059] Specifically, the overall injection molding uniformity is reflected by the density difference (regional density difference) between the root and the top of the umbrella skirt; when the surface density is greater than or equal to the first preset surface density characterization value and less than the second preset surface density characterization value, the specific defect type is further located by the bubble parameters (root bubble diameter, top bubble number). The root bubbles affect the bending strength, so a higher weight is given to the root bubble diameter; the top bubbles can be alleviated by the coating, so the weight is lower; when the surface density is greater than or equal to the second preset surface density characterization value, it is judged whether the local compaction or poor fluidity caused by poor exhaust leads to insufficient end filling through the thickness standard deviation; this design conforms to the troubleshooting logic of "first overall then local" in the injection molding process.

[0060] Specifically, the value range of the first preset surface density characterization value is (0.07 g / cm 3 , 0.09 g / cm 3 ), and the value range of the second preset surface density characterization value is (0.10 g / cm 3 , 0.17 g / cm 3 ). Preferably, the first preset surface density characterization value is 0.08 g / cm 3 , and the second preset surface density characterization value is 0.13 g / cm 3 .

[0061] Specifically, the process of obtaining the surface density characterization value includes:

[0062] Measure the densities of a number of measurement points in the first annular region and the second annular region respectively to obtain the density of the first annular region and the density of the second annular region, and obtain the difference between the density of the first annular region and the density of the second annular region, which is denoted as the regional density difference;

[0063] Obtain the regional density differences of a number of petticoats 2;

[0064] Calculate the arithmetic mean of the regional density differences of all petticoats 2, which is denoted as the surface density characterization value;

[0065] Among them, the ring width of the first annular region is greater than the ring width of the second annular region, the area of the first annular region is equal to the area of the second annular region, and the number of measurement points in the first annular region is equal to the number of measurement points in the second annular region.

[0066] Specifically, the first annular region is located at the root where the petticoat is connected to the insulating tube, and the second annular region is located at the top of the petticoat far from the insulating tube.

[0067] In this embodiment, the ring width of the first annular region is set to 30% of the total radial length of the petticoat, and the ring width of the second annular region is set to 10% of the total radial length of the petticoat.

[0068] In this embodiment, an ultrasonic densitometer is used to measure the densities of a number of measurement points in the first annular region and the second annular region.

[0069] Specifically, under the condition that the surface density characterization value is greater than or equal to the first preset surface density characterization value and less than the second preset surface density characterization value, the injection molding of the casing is re-determined according to the bubble evaluation value of the petticoat 2 whether it meets the preset standard, and, under the condition that the surface density characterization value is greater than or equal to the second preset surface density characterization value, determine the reason for the non-compliance of the injection molding according to the thickness distribution characterization value of the petticoat 2.

[0070] Specifically, re-determine whether the injection molding of the casing meets the preset standard according to the bubble evaluation value of the petticoat 2. Among them, if the bubble evaluation value is less than the first preset bubble threshold of 0.45, it is determined that the injection molding of the casing meets the preset standard;

[0071] If the bubble evaluation value is greater than or equal to the first preset bubble threshold and less than the second preset bubble threshold of 0.85, it is determined that the injection molding of the casing does not meet the preset standard, and the injection pressure is increased according to the difference between the bubble evaluation value and the first preset bubble threshold;

[0072] If the bubble evaluation value is greater than or equal to the second preset bubble threshold, it is determined that the injection molding of the casing does not meet the preset standard, and the injection molding is stopped for maintenance.

[0073] The value range of the first preset bubble threshold is (0.31, 0.65), and the value range of the second preset bubble threshold is (0.66, 0.95). Preferably, the first preset bubble threshold is selected as 0.45, and the second preset bubble threshold is selected as 0.85.

[0074] The bubble evaluation value of a single umbrella skirt is calculated by the following formula:

[0075]

[0076] In the formula, P i represents the bubble evaluation value of the i-th umbrella skirt 2; α represents the first weight, and α is set to 0.7; D i represents the diameter of the largest bubble at the root of the i-th umbrella skirt 2; D0 represents the preset bubble diameter at the root of the umbrella skirt 2, and D0 is set to 0.3 mm; β represents the second weight, and β is set to 0.3; N i represents the number of bubbles at the top of the i-th umbrella skirt 2; N0 represents the preset number of bubbles at the top of the umbrella skirt 2, and N0 is set to 15.

[0077] In this embodiment, D0 is set to 0.3 mm, which is obtained by taking the arithmetic mean of the bubble diameters of qualified products through historical data statistics. N0 is set to 15, which is obtained by taking the maximum allowable number of top bubbles of qualified products through historical data statistics.

[0078] The bubble evaluation value of the umbrella skirt 2 is the arithmetic mean of the bubble evaluation values of all umbrella skirts 2.

[0079] Specifically, an industrial camera is used to collect images of the root area and the top area of the umbrella skirt 2. An image segmentation algorithm such as threshold segmentation or edge detection is used to identify the bubble area, and the maximum diameter of the root bubbles and the number of top bubbles are calculated. The specific type of the image segmentation algorithm is not limited, as long as it can meet the bubble acquisition requirements.

[0080] Specifically, the root of the umbrella skirt 2 directly bears mechanical loads, and the bubbles generated at the root will reduce the bending strength of the umbrella skirt 2; the top bubbles of the umbrella skirt 2 will cause surface discharge, but it can be partially alleviated by a hydrophobic coating. Therefore, the value of the first weight at the root of the umbrella skirt 2 is greater than the value of the second weight at the top of the umbrella skirt 2;

[0081] Specifically, through the quantification of the bubble evaluation value, the abnormal state of the injection molding process can be accurately identified, and targeted measures can be triggered, improving the product reliability.

[0082] Specifically, several adjustment methods are set for the increase of the injection molding pressure. Among them, if the bubble difference is less than the first preset bubble difference of 0.15, the injection molding pressure is increased to the corresponding value by using the first pressure adjustment coefficient of 1.02;

[0083] If the bubble difference is greater than or equal to the first preset bubble difference and less than the second preset bubble difference of 0.27, the injection pressure is increased to the corresponding value using the second pressure adjustment coefficient of 1.04;

[0084] If the bubble difference is greater than or equal to the second preset bubble difference, the injection pressure is increased to the corresponding value using the third pressure adjustment coefficient of 1.06;

[0085] The bubble difference is the difference between the bubble evaluation value and the first preset bubble threshold.

[0086] Specifically, the reason for the injection molding not meeting the preset standard is determined according to the thickness distribution characterization value at the top of the umbrella skirt 2, where,

[0087] If the thickness distribution characterization value is less than the preset thickness distribution characterization value of 0.06 mm, it is determined that the reason for the injection molding not meeting the preset standard is poor mold exhaust and a warning is issued;

[0088] If the thickness distribution characterization value is greater than or equal to the preset thickness distribution characterization value, it is determined that the reason for the injection molding not meeting the preset standard is poor fluidity of the material, and the injection temperature of the material is increased according to the difference between the thickness distribution characterization value and the preset thickness distribution characterization value;

[0089] Specifically, when it is determined that the injection molding of the transformer bushing does not meet the preset standard, it is necessary to determine whether the problem is caused by the uneven thickness distribution at the top of the thin umbrella skirt 2;

[0090] When the mold exhaust hole is blocked, gas retention causes local compaction of the material, forming a high-density area, but the thickness uniformity is not damaged due to the high precision of the mold cavity;

[0091] Poor fluidity of the melt material will cause insufficient filling at the filling end, that is, the top of the umbrella skirt 2, resulting in a local thickness reduction.

[0092] In this embodiment, the preset thickness distribution characterization value is selected as 0.06 mm. The preset thickness distribution characterization value is obtained by taking the maximum value of the thickness distribution characterization values of several qualified umbrella skirts 2 in history, but the above values are not limited to this, and those skilled in the art can also adjust the values according to actual needs.

[0093] The thickness distribution characterization value is determined by the thickness at the edge of the top of the umbrella skirt 2;

[0094] The process of obtaining the thickness distribution characterization value:

[0095] Use an X-ray CT scanner to scan the target bushing, three-dimensionally reconstruct the structure of the umbrella skirt 2, and extract the outer edge contour curve of the top of the umbrella skirt 2;

[0096] Use a laser thickness gauge to measure the distance between the inner and outer walls of several observation points on the edge contour curve of the top of a single umbrella skirt 2, and obtain the arithmetic mean of the distance between the inner and outer walls of the top edge of the single umbrella skirt 2, which is denoted as the thickness of the top edge of the single umbrella skirt 2;

[0097] Obtain the thicknesses of the top edges of all umbrella skirts 2, and calculate the standard deviation of the thicknesses, which is denoted as the thickness distribution characterization value.

[0098] Specifically, the increase amplitude of the injection molding temperature of the material is positively correlated with the thickness difference. Among them, the positive correlation is, for example, a linear positive correlation or a non-linear positive correlation. The linear slope of the linear positive correlation is not specifically limited. It can be understood that the larger the thickness difference, the greater the increase amplitude of the injection molding temperature of the material; the thickness difference is the difference between the thickness distribution characterization value and the preset thickness distribution characterization value.

[0099] On the other hand, the embodiment of the present invention provides a molding system applicable to the molding method of a large creepage transformer bushing, including an injection molding module, which includes an injection unit for injecting the material, a mold unit for molding the material, and a cooling unit for cooling the target bushing;

[0100] A data acquisition module, which is connected to the injection molding module, includes a density acquisition unit for acquiring the density of the umbrella skirt 2, an image acquisition unit for acquiring the surface bubbles of the umbrella skirt 2, and a thickness acquisition unit for acquiring the thickness of the umbrella skirt 2;

[0101] An injection control module, which is respectively connected to the injection molding module and the data acquisition module, is used to, when it is determined that the injection molding of the bushing does not meet the preset standard according to the surface density characterization value, secondarily determine whether the injection molding of the bushing meets the preset standard according to the bubble evaluation value of the umbrella skirt 2, or determine the reason for the injection molding not meeting the preset standard according to the thickness distribution characterization value of the umbrella skirt 2.

[0102] In this embodiment, the injection unit uses an injection molding machine; the mold unit includes an upper mold, a lower mold, and a mold core. The mold cavity is designed as an axially arranged umbrella skirt 2 structure, and several groups of exhaust grooves are provided in the mold; the cooling unit uses a water cooling circulation system, and the cooling pipes are arranged along the contour of the mold cavity.

[0103] Specifically, the density acquisition unit is an ultrasonic density meter, the image acquisition unit is an industrial camera, and the thickness acquisition unit is a laser thickness gauge.

[0104] In this embodiment, the specific structure of the injection control module is not limited. It itself and each unit therein can be composed of logic components, and the logic components include field programmable components, computers, or microprocessors in computers.

[0105] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle 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 these changes or substitutions will all fall within the protection scope of the present invention.

[0106] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A forming method for a large creepage transformer bushing, characterized in that, Including: After heating the material, injecting the material into a mold under a preset injection pressure and a preset injection temperature, maintaining pressure and cooling to obtain a target sleeve; Obtaining the densities of several umbrella skirts of the target sleeve, and obtaining a surface density characterization value of the umbrella skirt; When it is determined that the injection molding of the sleeve does not meet the preset standard according to the surface density characterization value, obtaining a bubble evaluation value by the bubble diameter at the root of the umbrella skirt and the number of bubbles at the top of the umbrella skirt, and obtaining a thickness distribution characterization value by the thickness of the edge at the top of the umbrella skirt; Under the condition that the surface density characterization value is greater than or equal to a first preset surface density characterization value and less than a second preset surface density characterization value, secondarily determining whether the injection molding of the sleeve meets the preset standard according to the bubble evaluation value of the umbrella skirt, and, under the condition that the surface density characterization value is greater than or equal to the second preset surface density characterization value, determining the reason for the non - compliance of the injection molding with the preset standard according to the thickness distribution characterization value of the umbrella skirt.

2. The forming method of the large creepage transformer bushing according to claim 1, characterized in that, The target sleeve includes an insulating tube and several umbrella skirts uniformly arranged along the axial direction of the insulating tube. Among them, the end connecting the umbrella skirt to the insulating tube is denoted as the root of the umbrella skirt, and the end of the umbrella skirt away from the insulating tube is denoted as the top of the umbrella skirt.

3. The forming method of the large creepage transformer bushing according to claim 2, characterized in that In response to the surface density characterization value of the umbrella skirt being greater than or equal to the first preset surface density characterization value, it is determined that the injection molding of the sleeve does not meet the preset standard.

4. The forming method of the large creepage transformer bushing according to claim 3, characterized in that The process of obtaining the surface density characterization value includes: Measuring the densities of several measurement points in a first annular region and a second annular region respectively to obtain the density of the first annular region and the density of the second annular region, and obtaining the difference between the density of the first annular region and the density of the second annular region, denoted as the regional density difference; Obtaining the regional density differences of several umbrella skirts; Calculating the arithmetic mean of the regional density differences of all umbrella skirts, denoted as the surface density characterization value; Among them, the first annular region is located at the root where the umbrella skirt is connected to the insulating tube, the second annular region is located at the top of the umbrella skirt away from the insulating tube, the ring width of the first annular region is greater than the ring width of the second annular region, and the number of measurement points in the first annular region is equal to the number of measurement points in the second annular region.

5. The forming method of the large creepage transformer bushing according to claim 4, characterized in that, The process of secondarily determining that the injection molding of the sleeve does not meet the preset standard according to the bubble evaluation value of the umbrella skirt includes: Comparing the bubble evaluation value with a first preset bubble threshold and a second preset bubble threshold respectively; If the bubble evaluation value is greater than or equal to the first preset bubble threshold and less than the second preset bubble threshold, it is determined that the injection molding of the sleeve does not meet the preset standard, and the injection pressure is increased according to the difference between the bubble evaluation value and the first preset bubble threshold; If the bubble evaluation value is greater than or equal to the second preset bubble threshold, it is determined that the injection molding of the sleeve does not meet the preset standard, and the injection is stopped for maintenance; The bubble evaluation value is jointly determined by the bubble diameter at the root of the umbrella skirt and the number of bubbles at the top of the umbrella skirt.

6. The forming method of the large creepage transformer bushing according to claim 5, characterized in that, There are several adjustment methods for increasing the injection pressure, and each adjustment method has a different increase range for the injection pressure.

7. The forming method of the large creepage transformer bushing according to claim 6, characterized in that, Determine the reasons for the injection molding not meeting the preset standards based on the thickness distribution characterization value of the top of the umbrella skirt, including poor mold exhaust and issuing a warning, or poor fluidity of the material and increasing the injection temperature of the material according to the difference between the thickness distribution characterization value and the preset thickness distribution characterization value; The thickness distribution characterization value is determined by the thickness of the edge of the top of the umbrella skirt.

8. The forming method of the large creepage transformer bushing according to claim 7, characterized in that, The increase range of the injection temperature of the material is positively correlated with the thickness difference, where the thickness difference is the difference between the thickness distribution characterization value and the preset thickness distribution characterization value.

9. A forming system applicable to the forming method of the large creepage transformer bushing according to any one of claims 1-8, characterized in that, Including an injection molding module, which includes an injection unit for injecting the material, a mold unit for molding the material, and a cooling unit for cooling the target casing; A data acquisition module, which is connected to the injection molding module, includes a density acquisition unit for acquiring the density of the umbrella skirt, an image acquisition unit for acquiring the surface bubbles of the umbrella skirt, and a thickness acquisition unit for acquiring the thickness of the umbrella skirt; An injection control module, which is respectively connected to the injection molding module and the data acquisition module, is used to determine whether the injection of the casing meets the preset standards according to the surface density characterization value. Under the condition that the injection of the casing does not meet the preset standards, determine whether the injection of the casing meets the preset standards according to the bubble evaluation value of the umbrella skirt, or determine the reasons for the injection molding not meeting the preset standards according to the thickness distribution characterization value of the umbrella skirt.

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