A thin-walled sheathed cable and its rapid prototyping process

Abstract

The present invention discloses a thin-wall sheathed cable and its rapid prototyping process. Among them, the thin-wall sheathed cable includes a cable core, an insulating layer wrapped around the cable core, and an outermost sheath; wherein, the cable core is formed by stranding multiple copper single wires; the insulating layer uses a flame-retardant cross-linked polyethylene material; the sheath uses a modified nylon material. The printed mark of the thin-wall sheathed cable body of the present invention is on the surface of the insulation, the insulating layer and the sheath are extruded in sections, and the cable is formed in one step. The thin-wall sheathed cable of the present invention has the characteristics of flame retardancy, environmental protection, wear resistance, small outer diameter, light weight, fast heat dissipation, large relative current-carrying capacity, easy pipe threading construction, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and particularly to a thin-wall sheathed cable and its rapid prototyping process. Background Art

[0002] In the fields of modern power transmission and communication, cables, as key connecting components, their performance is directly related to the stability and safety of the entire system. With the booming development of aircraft, drones and other aircraft, the demand for thin-wall sheathed cables is also increasing. The aerospace field has extremely strict requirements for the performance of cables. It not only requires the cables to have excellent electrical and mechanical properties, but also needs to reduce the weight and volume of the cables as much as possible to improve the payload capacity and fuel efficiency of the aircraft. In addition, when the aircraft is flying at high altitudes, it will face more complex and harsh environmental conditions, such as drastic temperature changes, strong vibrations, radiation and humidity. This requires the cables to have excellent temperature resistance, wear resistance, moisture resistance and electromagnetic interference resistance.

[0003] The application advantages of thin-wall sheathed cables in the aerospace field are significant. First of all, by reducing the thickness of the insulation layer and the sheath, the thin-wall cables can significantly reduce the overall weight of the cables on the premise of ensuring electrical safety, thus contributing to the lightweight design of the aircraft. Secondly, the smaller outer diameter of the thin-wall sheathed cables helps to optimize the wiring layout inside the aircraft, improve the space utilization efficiency, and reduce the installation difficulty of the cables in a limited space. In addition, the rapid heat dissipation ability of the thin-wall sheathed cables enables them to better adapt to the complex thermal management requirements inside the aircraft and reduce the performance attenuation and safety hazards caused by temperature rise.

[0004] However, there are still some technical challenges in the existing thin-wall sheathed cables. On the one hand, how to further reduce the outer diameter and sheath thickness of the cables while maintaining electrical and mechanical properties is an urgent problem to be solved. On the other hand, in the production process, achieving an efficient and stable forming process to meet the needs of mass production is also a key issue in the research and development of thin-wall sheathed cables. Summary of the Invention

[0005] Based on the problems existing in the background art, the present invention provides a thin-wall sheathed cable and its rapid prototyping process. Compared with conventional cables, the thin-wall sheathed cable of the present invention has a small outer diameter, light weight, easy pipe threading, fast heat dissipation, large relative current-carrying capacity and convenient installation.

[0006] The present invention is implemented through the following technical solutions:

[0007] On the one hand, the present invention discloses a thin-wall sheathed cable, which includes a cable core, an insulation layer coated on the cable core, and an outermost sheath; wherein, the cable core is composed of multiple copper single wires stranded together; the insulation layer uses flame-retardant cross-linked polyethylene material; the sheath uses modified nylon material.

[0008] Further, the flame-retardant crosslinked polyethylene material comprises the following raw materials in parts by weight: 100 parts of low-density polyethylene resin, 6-15 parts of modified ethylene-methyl acrylate copolymer, 2-8 parts of melamine formaldehyde resin, 0.5-1.4 parts of crosslinking agent, 0.8-1.6 parts of nano filler, 0.1-1 part of antioxidant, and 1-3 parts of lubricant.

[0009] Further, the preparation method of the modified ethylene-methyl acrylate copolymer is specifically as follows: dissolving the ethylene-methyl acrylate copolymer in N-formyldimethylamine, adding vinyltriethoxysilane under nitrogen protection, stirring and mixing, heating to 60-70 °C, dropping an initiator azodiisobutyronitrile, controlling the dropping of the initiator within 2 hours, continuously stirring and reacting for 7-9 h after the dropping of the initiator is completed, adding chloroform, filtering, washing, and drying under vacuum conditions to obtain the modified ethylene-methyl acrylate copolymer.

[0010] Further, the molar ratio of the ethylene-methyl acrylate copolymer to vinyltriethoxysilane is (3-8):1, and the mass of the initiator accounts for 0.1-0.3% of the total mass of vinyltriethoxysilane.

[0011] Further, the crosslinking agent is dicumyl peroxide;

[0012] The nano filler is nano magnesium oxide treated with silane coupling agent on the surface;

[0013] The antioxidant is antioxidant 1010;

[0014] The lubricant is calcium stearate.

[0015] Further, the modified nylon material comprises the following raw materials in parts by weight: 60-70 parts of nylon 66, 30-40 parts of nylon 66, 3-6 parts of maleic anhydride grafted ethylene-propylene-diene monomer rubber, 5-10 parts of halogen-free flame retardant, 4-6 parts of modified nano silica, 1-3 parts of wear-resistant agent, 0.1-1 part of antioxidant, and 0.2-0.8 part of lubricant.

[0016] Further, the preparation method of the modified nano silica is specifically as follows: dispersing nano silica in toluene, dropping γ-aminopropyltriethoxysilane under nitrogen protection, reacting at 80 °C for 24 h, filtering, washing, and drying under vacuum to obtain substance A; dispersing substance A in methanol, dropping methyl acrylate under nitrogen protection, reacting at 50 °C for 72 h, filtering, washing, and drying under vacuum to obtain substance B; dispersing substance B in methanol, dropping ethylenediamine under nitrogen protection, reacting at 50 °C for 72 h, filtering, washing, and drying under vacuum to obtain the modified nano silica.

[0017] Further, the halogen-free flame retardant is Fyro l f l ex RDP;

[0018] The wear-resistant agent is PTFE micropowder;

[0019] The antioxidant is antioxidant 1010;

[0020] The lubricant is calcium stearate.

[0021] On the other hand, the present invention discloses a rapid prototyping process for a thin-wall sheathed cable, comprising the following steps:

[0022] S1. Mix the low-density polyethylene resin, modified ethylene-methyl acrylate copolymer, and melamine formaldehyde resin in the raw materials of the flame-retardant cross-linked polyethylene material evenly, heat, and add a cross-linking agent, nano-fillers, antioxidants, and lubricants, and mix evenly to obtain mixture A;

[0023] S2. Extrude mixture A outside the cable core and cool it to form an insulating layer;

[0024] S3. Print letter codes on the surface of the insulating layer;

[0025] S4. Put nylon 6, nylon 66, maleic anhydride-grafted ethylene propylene diene monomer rubber, halogen-free flame retardant, modified nano-silica, wear-resistant agent, antioxidant, and lubricant in the raw materials of the modified nylon material into a high-speed mixer and mix evenly to obtain mixture B;

[0026] S5. Extrude mixture B outside the insulating layer and cool it to form a sheath, thereby obtaining the thin-wall sheathed cable.

[0027] Further, the thickness of the sheath is 0.1 - 0.3 mm.

[0028] Advantages of the present invention:

[0029] 1. The printed mark of the thin-wall sheathed cable body of the present invention is on the surface of the insulation. The insulating layer and the sheath are extruded in sections, and the cable is formed in one step. The thin-wall sheathed cable of the present invention has the characteristics of flame retardancy, environmental protection, wear resistance, small outer diameter, light weight, fast heat dissipation, large relative current-carrying capacity, and easy pipe threading construction.

[0030] 2. The insulation layer of the thin-wall sheathed cable of the present invention is designed based on a flame-retardant cross-linked polyethylene material. By reasonably proportioning low-density polyethylene resin, modified ethylene-methyl acrylate copolymer, melamine formaldehyde resin, cross-linking agent, nano-fillers, etc., it is ensured that the cable still has excellent dielectric properties and mechanical strength even when the insulation layer thickness is reduced to 70% (or even lower) of that of conventional products. The modified ethylene-methyl acrylate copolymer realizes further functionalization of the polymer by introducing vinyltriethoxysilane into the basic ethylene-methyl acrylate chain. Vinyltriethoxysilane can not only undergo cross-linking reactions with active groups in the polymer matrix, but also improve the compatibility between the polymer and inorganic fillers, thereby enhancing the overall performance of the material. The modified ethylene-methyl acrylate copolymer and the cross-linking agent together promote the formation of a cross-linked network between polymer chains. The formation of the cross-linked network improves the thermal stability, mechanical strength, and creep resistance of the material, enabling the material to maintain excellent structural stability under high-temperature and stress conditions, and being suitable for use as a thin-wall cable sheath.

[0031] 3. The outer sheath of the thin-wall sheathed cable of the present invention is mainly composed of nylon 6 and nylon 66. The ratio of the two enables the sheath to have good mechanical properties while having good thermal stability and wear resistance. The addition of maleic anhydride-grafted ethylene propylene diene monomer improves the toughness of the nylon material and enhances its impact resistance, ensuring that even when the sheath is thin, the material can still maintain excellent physical properties and is not easily cracked or worn. Nano-silica, through surface modification (three-step modification with γ-aminopropyltriethoxysilane, methyl acrylate, and ethylenediamine), improves its compatibility with the nylon matrix, forms a strong interfacial bonding force, and significantly enhances the mechanical strength and wear resistance of the material. The nano-effect of nano-silica particles can also enhance the rigidity and heat resistance of the material, while improving the anti-aging property of the sheath material. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings are used to provide further explanation of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0033] Figure 1 It is the external view of the thin-wall sheathed cable prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solutions of the present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0035] Example 1

[0036] A rapid prototyping process for a thin-wall sheathed cable includes the following steps:

[0037] S1. Prepare the raw materials in parts by weight of the following flame-retardant crosslinked polyethylene material: 100 parts of low-density polyethylene resin, 12 parts of modified ethylene-methyl acrylate copolymer, 6 parts of melamine formaldehyde resin, 1.0 part of crosslinking agent, 1.2 parts of nano filler, 0.5 part of antioxidant, and 2 parts of lubricant; Mix the low-density polyethylene resin, modified ethylene-methyl acrylate copolymer, and melamine formaldehyde resin in the raw materials of the flame-retardant crosslinked polyethylene material evenly, heat, and add the crosslinking agent, nano filler, antioxidant, and lubricant, and mix evenly to obtain mixture A;

[0038] Among them, the preparation method of the modified ethylene-methyl acrylate copolymer is specifically as follows: Dissolve the ethylene-methyl acrylate copolymer in N-formyldimethylamine, add vinyltriethoxysilane under nitrogen protection, and stir and mix the molar ratio of ethylene-methyl acrylate copolymer to vinyltriethoxysilane at 4:1, heat up to 70 °C, dropwise add the initiator azobisisobutyronitrile, the mass of the initiator accounts for 0.2% of the total mass of vinyltriethoxysilane, the dropping of the initiator is controlled within 2 hours, and continue to stir and react for 8 hours after the dropping of the initiator is completed, add chloroform, filter, wash, and dry under vacuum conditions to obtain the modified ethylene-methyl acrylate copolymer;

[0039] The crosslinking agent is dicumyl peroxide;

[0040] The nano filler is nano magnesium oxide treated with silane coupling agent on the surface;

[0041] The antioxidant is antioxidant 1010;

[0042] The lubricant is calcium stearate;

[0043] S2. Extrude mixture A outside the cable core and cool it to form an insulating layer;

[0044] Among them, the cable core is stranded by 19 copper single wires, and the diameter of a single copper single wire is 0.55 mm;

[0045] S3. Spray print the letter code on the surface of the insulating layer;

[0046] S4. Prepare the raw materials in parts by weight of the following nylon material: 5 parts of nylon 6, 35 parts of nylon 66, 5 parts of maleic anhydride grafted ethylene-propylene-diene monomer rubber, 8 parts of halogen-free flame retardant, 5 parts of modified nano silica, 2 parts of wear-resistant agent, 0.5 part of antioxidant, and 0.6 part of lubricant; Put the nylon 6, nylon 66, maleic anhydride grafted ethylene-propylene-diene monomer rubber, halogen-free flame retardant, modified nano silica, wear-resistant agent, antioxidant, and lubricant in the raw materials of the modified nylon material into a high-speed mixer and mix evenly to obtain mixture B;

[0047] Among them, the preparation method of the modified nano-silica is specifically as follows: Disperse nano-silica in toluene, dropwise add γ-aminopropyltriethoxysilane under nitrogen protection, react at a constant temperature of 80 °C for 24 h, filter, wash, and vacuum dry to obtain Substance A; Disperse Substance A in methanol, dropwise add methyl acrylate under nitrogen protection, react at a constant temperature of 50 °C for 72 h, filter, wash, and vacuum dry to obtain Substance B; Disperse Substance B in methanol, dropwise add ethylenediamine under nitrogen protection, react at a constant temperature of 50 °C for 72 h, filter, wash, and vacuum dry to obtain the modified nano-silica;

[0048] The halogen-free flame retardant is Fyro l f l ex RDP;

[0049] The wear-resistant agent is PTFE fine powder;

[0050] The antioxidant is antioxidant 1010;

[0051] The lubricant is calcium stearate;

[0052] S5. Extrude the mixture B outside the insulating layer, cool and form to obtain a sheath, thus obtaining the thin-wall sheath cable.

[0053] The finally obtained thin-wall sheath cable has an insulating layer thickness of 0.575 mm, a sheath thickness of 0.15 mm, and a minimum thickness of 0.10 mm.

[0054] Example 2

[0055] The difference between this example and Example 1 is that in step S1, the following raw materials in parts by weight of the flame-retardant cross-linked polyethylene material are prepared: 100 parts of low-density polyethylene resin, 10 parts of modified ethylene-methyl acrylate copolymer, 6 parts of melamine formaldehyde resin, 0.8 part of cross-linking agent, 1.4 parts of nano-filler, 0.5 part of antioxidant, and 2 parts of lubricant.

[0056] Example 3

[0057] The difference between this example and Example 1 is that in step S4, the following raw materials in parts by weight of the nylon material are prepared: 5 parts of nylon 66, 35 parts of nylon 66, 4 parts of maleic anhydride-grafted ethylene propylene diene monomer rubber, 8 parts of halogen-free flame retardant, 6 parts of modified nano-silica, 2 parts of wear-resistant agent, 0.5 part of antioxidant, and 0.6 part of lubricant.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that in step S1, ethylene-methyl acrylate copolymer is directly used.

[0060] Comparative Example 2

[0061] The difference between this comparative example and Example 1 is that in step S1, no nano-filler is added.

[0062] Comparative Example 3

[0063] The difference between this comparative example and Example 1 is that nano-silica is directly added in step S4.

[0064] Comparative Example 4

[0065] The difference between this comparative example and Example 1 is that the modification step of nano-silica in step S4 is as follows: nano-silica is dispersed in toluene, γ-aminopropyltriethoxysilane is added dropwise under nitrogen protection, the reaction is carried out at a constant temperature of 80 °C for 24 h, filtered, washed, and dried in vacuum to obtain modified nano-silica.

[0066] Comparative Example 5

[0067] The difference between this comparative example and Example 1 is that maleic anhydride grafted ethylene-propylene-diene rubber is not added in step S4.

[0068] Test Example 1

[0069] This test example tested the properties of the flame-retardant crosslinked polyethylene materials prepared in Examples 1-2 and Comparative Examples 1-2. The tensile strength and elongation at break were tested with reference to JB / T 10437-2004 "Crosslinkable Polyethylene Insulating Material for Electric Wire and Cable"; the relative permittivity of the test specimens was tested using a Concept80 type broadband dielectric and impedance spectrometer under the test conditions of 0.1 Hz and a test temperature of 20 °C; with reference to Appendix C of GB / T 14049 2008 "Rated Voltage 10 kV Aerial Insulated Cable", a xenon lamp weathering chamber was used for the aging resistance test, and the tensile strength, elongation at break, and permittivity were measured after 42 d of aging; the specific data are shown in Table 1.

[0070] Table 1

[0071] Group Example 1 Example 2 Comparative Example 1 Comparative Example 2 Tensile strength / MPa 23.4 22.0 19.6 18.7 Tensile strength after 42 days of aging / MPa 22.1 20.9 16.2 14.9 Elongation at break / % 554 536 481 493 Elongation at break after 42 days of aging / % 550 540 467 462 Dielectric constant 2.07 2.11 2.43 2.64 Dielectric constant after 42 days of aging 2.15 2.19 2.67 2.82

[0072] As can be seen from the data in Table 1, the flame-retardant crosslinked polyethylene materials prepared in Example 1 and Example 2 of the present invention have good mechanical properties and dielectric properties while reducing the thickness of the insulating layer. The introduction of the modified ethylene-methyl acrylate copolymer, melamine formaldehyde resin and nano-fillers has formed a denser crosslinked network inside the material, which improves the tensile strength of the material. In particular, the modification effect of vinyltriethoxysilane not only improves the mechanical properties of the copolymer, but also enhances the overall strength of the material through the interaction with the nano-fillers. The introduction of the modified ethylene-methyl acrylate copolymer significantly improves the polarity uniformity of the material. In particular, the silanization effect of vinyltriethoxysilane reduces the dielectric loss of the material and makes the dielectric constant tend to be stable. The addition of nano-fillers further improves the insulation of the material, making the decline rate of the dielectric constant slower during the aging process. In Comparative Example 1, the unmodified ethylene-methyl acrylate copolymer is directly used. Due to its poor compatibility with the low-density polyethylene matrix, the crosslinked network is not as dense as that of the modified copolymer, so the tensile strength will be lower. Due to the poor compatibility between the unmodified ethylene-methyl acrylate copolymer and the matrix and the uneven distribution of polar groups, the dielectric constant is relatively high, and it is easily affected by the electric field during the aging process, resulting in a significant increase in the dielectric constant. In Comparative Example 2, no nano-fillers are used, resulting in a significant reduction in the strength and toughness of the material. The filler can improve the mechanical properties of the material. Comparative Example 2 without filler will perform poorly in terms of tensile strength and elongation at break. Due to the lack of nano-fillers, its insulation performance is reduced, resulting in a relatively high dielectric constant and a faster decline during the aging process.

[0073] Test Example 2

[0074] In this test example, the properties of the nylon materials prepared in Example 1, Example 3 and Comparative Examples 3-5 were tested. The tensile strength and elongation at break were tested according to GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets"; the wear resistance was tested according to GB / T 3960-2016 "Test Method for Sliding Friction and Wear of Plastics". The test results are shown in Table 2.

[0075] Table 2

[0076]

[0077]

[0078] As can be seen from the data in Table 2, the nylon sheath prepared by the present invention not only has good tensile strength and elongation at break, but also has excellent wear resistance. In Comparative Example 3, nano-silica was directly added, and its interfacial bonding force with the nylon matrix was poor, which easily formed interfacial defects, resulting in a significant decrease in the tensile strength of the material. Due to the relatively large rigidity of the nano-silica particles, the unmodified nano-silica would reduce the toughness of the material, so the elongation at break also decreased accordingly. Although nano-silica has the potential to enhance wear resistance, due to the poor bonding force with the matrix, the improvement of wear resistance is limited. In Comparative Example 4, only aminopropyl-modified nano-titanium dioxide was used, and its material properties were significantly better than those in Comparative Example 3, but not as good as those in Examples 1 and 3. In Comparative Example 5, maleic anhydride-grafted ethylene-propylene-diene rubber was not used. As a toughening agent, without adding it, the various properties of the material were significantly reduced. Especially when the sheath material is relatively thin, it can reduce the risk of cracking and breakage. In the present invention, through three-step modification of nano-silica, in the first step, aminopropyl modification introduces amino groups, enhancing the surface polarity of nano-silica, making it easier to be compatible with nylon and increasing the interfacial strength; in the second step, methyl acrylate modification, methyl acrylate undergoes a nucleophilic addition reaction with the amino group through its carboxyl part to form an ester bond, thereby introducing acrylate groups on the surface of nano-silica. The acrylic groups also have good compatibility with nylon groups, and acrylate has relatively high reactivity, which helps subsequent chemical reactions with other functional groups or the matrix to improve the overall mechanical properties of the material; in the third step, ethylenediamine modification, amine functional groups are introduced through the cross-linking reaction of acrylate groups with the amino groups of ethylenediamine. The presence of amine groups helps to further enhance the compatibility between nano-silica and the nylon matrix, forming a stronger interfacial bond. The ethylenediamine-modified nano-silica has better dispersibility and mechanical enhancement effect, and the amine groups can also form hydrogen bonds or chemical bonds with the polymer chains, enhancing the tensile strength and elongation at break of the material.

[0079] Example 4

[0080] During the manufacturing process of the cable according to any one of Examples 1-3, based on the cable encapsulation length, a plurality of acquisition start points and acquisition end points of the cable are determined, and an insulation layer data set and a sheath data set are established;

[0081] And after the insulation layer or the sheath film is completed respectively, starting from the acquisition start point and ending at the acquisition end point, at a preset interval, the radius of the insulation layer film-covered cable and the radius of the sheath film-covered cable of the current detected cable segment are respectively collected;

[0082] And the radius of the insulation layer film-covered cable and the radius of the sheath film-covered cable are respectively compared with their corresponding initial cable radii to obtain the measured thickness of the insulation layer and the measured thickness of the sheath at each acquisition point;

[0083] Send the measured thickness of the insulation layer to the insulation layer data set, and send the measured thickness of the sheath to the sheath data set for temporary storage;

[0084] Meanwhile, compare the latest data in the insulation layer data set and the sheath data set with the preset minimum value respectively;

[0085] If the latest data in both the insulation layer data set and the sheath data set are greater than or equal to the preset minimum value, determine that the currently detected cable section is qualified, and compare the latest data in the insulation layer data set with the preset insulation layer thickness to obtain the insulation layer error. When the insulation error is greater than the first preset value, increment the insulation layer error count by 1;

[0086] Compare the latest data in the sheath data set with the preset sheath thickness to obtain the sheath layer error. When the sheath layer error is greater than the second preset value, increment the sheath layer error count by 1;

[0087] Based on the insulation layer error count result, determine the first error count frequency corresponding to the acquisition point on the insulation layer of the currently detected cable section. Meanwhile, based on the insulation layer error count result, determine the second error count frequency corresponding to the acquisition point on the sheath layer of the currently detected cable section;

[0088] When the first error count frequency or the second error count frequency is greater than the preset frequency threshold, send a feed speed adjustment instruction to the control end;

[0089] Otherwise, continue the detection;

[0090] If the latest data in either the insulation layer data set or the sheath data set is less than the preset minimum value, determine that the currently detected cable section is unqualified, replace the acquisition end point with the current acquisition point as the imperfect end point, and generate a packaging unqualified information based on the acquisition start point and the imperfect end point and send it to the control end for display.

[0091] In this embodiment, the cable packaging length refers to the length of a roll of cable in the packaging stage. For example, 100m, 200m, 500m, etc., which can be flexibly set according to actual production requirements.

[0092] In this embodiment, the initial cable radius refers to the radius of the bare wire without the insulation layer or the radius of the cable without the protective sheath.

[0093] In this embodiment, the insulation layer data set refers to a data set storing all the measured thickness data of the insulation layer corresponding to each encapsulated cable segment, and the sheath data set refers to a data set storing all the measured thickness data of the sheath corresponding to each encapsulated cable segment. Each encapsulated cable segment corresponds to an insulation layer data set and a sheath layer data set. When a new acquisition starting point is detected, the corresponding insulation layer data set or sheath layer data set is automatically generated. After the acquisition end point data is detected, the system automatically uploads the data in the insulation layer data set and the sheath layer data set to the cloud and then deletes the insulation layer data set and the sheath layer data set.

[0094] The preset interval refers to the interval for setting acquisition points. For example, 0.05m, 0.1m, 0.5m, etc., which can be flexibly set according to the detection requirements.

[0095] In this embodiment, the first preset value being less than means the absolute value of the ratio of the difference between the expected insulation layer thickness and the thinnest value to the expected insulation layer thickness (i.e., the preset insulation layer thickness, which can be flexibly set according to production requirements); the second preset value is less than the absolute value of the ratio of the difference between the expected sheath thickness (i.e., the preset sheath thickness, which can be flexibly set according to production requirements) and the thinnest value to the expected sheath thickness.

[0096] In this embodiment, the insulation layer error refers to the absolute value of the ratio of the difference between the measured thickness of the insulation layer and the preset insulation layer thickness to the preset insulation layer thickness; the sheath layer error refers to the absolute value of the ratio of the difference between the measured thickness of the sheath and the preset sheath thickness to the preset sheath thickness.

[0097] In this embodiment, the first error counting frequency refers to the ratio of the current insulation layer error count value of the detected cable segment to the total number of acquisition points of the current detected cable segment; the second error counting frequency refers to the ratio of the current sheath layer error count value of the detected cable segment to the total number of acquisition points of the current detected cable segment.

[0098] Advantages of the above technical solution: In the process of cable manufacturing, the present invention segments the cable according to the encapsulation length of the cable, determines the data acquisition start point and end point of the cable segment corresponding to each detection, and uses the acquisition start point as the start point and the acquisition end point as the end point to perform equidistant data acquisition, obtains the radius of the insulated layer-coated cable and the radius of the sheath-coated cable of the currently detected cable segment, and compares them with the corresponding initial cable radius, obtains the measured thickness of the insulated layer and the measured thickness of the sheath at each acquisition point and temporarily stores them in the insulated layer data set and the sheath data set corresponding to the currently detected cable segment respectively, and respectively compares the latest data in the insulated layer data set and the sheath data set with the preset minimum value, and determines whether the currently detected power segment is qualified according to the comparison result, which can ensure that the thickness of the protective layer (including the insulated layer and the sheath layer) of the cable product is greater than the minimum value, realizes the detection of the protective layer of the whole cable, provides a basis for the encapsulation of the cable, and at the same time, when the currently detected cable segment is qualified, compares the latest data in the insulated layer data set with the preset insulated layer thickness to obtain the insulated layer error. When the insulation error is greater than the first preset value, the insulation error count is incremented by 1; compares the latest data in the sheath data set with the preset sheath thickness to obtain the sheath layer error. When the sheath layer error is greater than the second preset value, the sheath layer error count is incremented by 1; based on the insulation error count result, determines the first error count frequency corresponding to the acquisition points on the insulated layer of the currently detected cable segment, and at the same time, based on the insulation error count result, determines the second error count frequency corresponding to the acquisition points on the sheath layer of the currently detected cable segment; when the first error count frequency or the second error count frequency is greater than the preset frequency threshold, sends a feed speed adjustment instruction to the control end, realizes the purpose of real-time correction of the subsequent cable manufacturing according to the real-time manufacturing situation of the current cable, can minimize the thickness error of the cable protective layer, improve the subsequent cable manufacturing accuracy and cable quality, and enhance the safety of the cable in use.

[0099] Embodiment 5

[0100] On the basis of Embodiment 4, when the first error count frequency or the second error count frequency is greater than the preset frequency threshold, sending a feed speed adjustment instruction to the control end includes:

[0101] When the first error count frequency is greater than the preset frequency threshold, obtain the insulation errors corresponding to all acquisition points in the insulation layer data set corresponding to the currently detected cable segment, calculate the average error of the insulation layer of the currently detected cable segment, and cluster the counted insulation layer errors to obtain the first large error set, and calculate the average value of the first large error;

[0102] Based on the average value of the first large error and the average error of the currently detected cable segment's insulation layer, obtain the first error large fluctuation index. Combine the insulation layer error counting frequency and the floating direction of each insulation layer error to respectively determine the first positive error large fluctuation index and the first negative error large fluctuation index of the currently detected cable segment's insulation layer;

[0103] Based on the first positive error large fluctuation index and the first negative error large fluctuation index, correct the average error of the cable segment's insulation layer to obtain the first error to be calibrated of the currently detected cable segment's insulation layer;

[0104] Based on the corresponding relationship between the thickness of mixture A and the extrusion speed, combine the current extrusion speed and the first error to be calibrated to determine the adjustment strategy for the extrusion speed of mixture A, generate the first extrusion speed adjustment instruction, and send it to the control end;

[0105] When the second error counting frequency is greater than the preset frequency threshold, obtain the sheath layer errors corresponding to all the acquisition points in the sheath dataset corresponding to the currently detected cable segment, calculate the average error of the sheath layer of the currently detected cable segment, and cluster the counted sheath layer errors to obtain the second large error set, and calculate the average value of the second large error;

[0106] Based on the average value of the second large error and the average error of the currently detected cable segment's insulation layer, obtain the second error large fluctuation index. Combine the insulation layer error counting frequency and the floating direction of each sheath layer error to respectively determine the second positive error large fluctuation index and the second negative error large fluctuation index of the currently detected cable segment's insulation layer;

[0107] Based on the second positive error large fluctuation index and the second negative error large fluctuation index, correct the average error of the cable segment's sheath layer to obtain the second error to be calibrated of the currently detected cable segment's insulation layer;

[0108] Based on the corresponding relationship between the thickness of mixture B and the extrusion speed, combine the current extrusion speed and the second error to be calibrated to determine the adjustment strategy for the extrusion speed of mixture B, generate the second extrusion speed adjustment instruction, and send it to the control end.

[0109] In this embodiment, the first large error set refers to the dataset composed of the counted insulation layer errors of the currently detected cable segment; the second large error set refers to the dataset composed of the counted sheath layer errors of the currently detected cable segment.

[0110] In this embodiment, the average value of the first large error refers to the average value of the insulation layer errors included in the first large error set. The average value of the second large error refers to the average value of the insulation layer errors included in the second large error set.

[0111] In this embodiment, the first error large fluctuation index is the ratio of the difference between the average value of the first large error and the average error of the insulating layer of the currently detected cable section to the average error of the insulating layer of the currently detected cable section. The second error large fluctuation index is the ratio of the difference between the average value of the second large error and the average error of the sheath layer of the currently detected cable section to the average error of the sheath layer of the currently detected cable section.

[0112] In this embodiment, the first positive error large fluctuation index is the product of the large insulating layer error counting frequency corresponding to the insulating error where the difference between the measured thickness of the insulating layer and the preset thickness of the insulating layer is greater than 0 and the first error large fluctuation index. The second positive error large fluctuation index is the product of the insulating layer error counting frequency corresponding to the large insulating error where the difference between the measured thickness of the insulating layer and the preset thickness of the insulating layer is less than 0 and the first error large fluctuation index;

[0113] Among them, the first positive error large fluctuation index is positive; the first positive error large fluctuation index is negative.

[0114] In this embodiment, the second positive error large fluctuation index is the product of the large sheath layer error counting frequency corresponding to the insulating error where the difference between the measured thickness of the sheath and the preset thickness of the sheath is greater than 0 and the second error large fluctuation index. The second positive error large fluctuation index is the product of the insulating layer error counting frequency corresponding to the large sheath layer error where the difference between the measured thickness of the sheath and the preset thickness of the sheath is less than 0 and the second error large fluctuation index;

[0115] Among them, the second positive error large fluctuation index is positive; the second positive error large fluctuation index is negative.

[0116] In this embodiment, the first error to be calibrated is the product of the sum of the first positive error large fluctuation index and the first negative error large fluctuation index and the average error of the insulating layer of the cable section.

[0117] In this embodiment, the second error to be calibrated is the product of the sum of the second positive error large fluctuation index and the second negative error large fluctuation index and the average error of the sheath layer of the cable section.

[0118] Beneficial effects of the above counting scheme: When the first error counting frequency or the second error counting frequency is greater than the preset frequency threshold in the present invention, the probability of significant fluctuations in the manufacturing thickness error of the insulating layer or sheath layer of the current detected cable section is determined according to the difference between the average error of the insulating layer or sheath layer and the average value of the large amplitude errors being counted (i.e., the first error large fluctuation index or the second error large fluctuation index). Then, according to the fluctuation distribution of the large amplitude errors in the positive and negative directions, the positive error large fluctuation index and the negative error large fluctuation index are determined. Then, based on the positive error large fluctuation index and the negative error large fluctuation index, the average error is corrected to determine the final error (i.e., the error to be calibrated), and according to the corresponding relationship between the mixture thickness and the extrusion speed, combined with the current extrusion speed and the final error, the adjustment strategy for the mixture extrusion speed is determined, a corresponding extrusion speed adjustment instruction is generated, and sent to the control end to control the extrusion to complete the extrusion speed adjustment, so that the correction of the extrusion speed conforms to the actual situation, ensuring that the cable manufacturing after the extrusion speed adjustment is closer to the expectation, providing a reliable basis for the automatic correction in the cable manufacturing process.

[0119] Finally, it should be noted that the above embodiments only represent several implementation manners of the present invention, and are not intended to limit the present invention. For those of ordinary skill in the art, any modifications, equivalent replacements, improvements, etc. made without departing from the concept of the present invention shall be included within the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. A thin-walled sheathed cable, characterized in that: It includes a cable core, an insulating layer covering the cable core, and an outermost sheath; wherein the cable core is formed by twisting multiple copper single wires; the insulating layer is made of flame-retardant cross-linked polyethylene material; and the sheath is made of modified nylon material; The flame retardant cross-linked polyethylene material comprises the following raw materials in parts by weight: 100 parts of low-density polyethylene resin, 6-15 parts of modified ethylene-methyl acrylate copolymer, 2-8 parts of melamine formaldehyde resin, 0.5-1.4 parts of cross-linking agent, 0.8-1.6 parts of nano filler, 0.1-1 parts of antioxidant, and 1-3 parts of lubricant; The modified nylon material comprises the following raw materials in parts by weight: nylon 660-70 parts, nylon 6630-40 parts, maleic anhydride grafted EPDM rubber 3-6 parts, halogen-free flame retardant 5-10 parts, modified nano-silicon dioxide 4-6 parts, wear-resistant agent 1-3 parts, antioxidant 0.1-1 parts, lubricant 0.2-0.8 parts; The preparation method of modified nano-silica is specifically as follows: disperse nano-silica in toluene, add γ-aminopropyltriethoxysilane dropwise under nitrogen protection, react at a constant temperature of 80°C for 24 hours, filter, wash, and vacuum dry to obtain substance A; disperse substance A in methanol, add methyl acrylate dropwise under nitrogen protection, react at a constant temperature of 50°C for 72 hours, filter, wash, and vacuum dry to obtain substance B; disperse substance B in methanol, add ethylenediamine dropwise under nitrogen protection, react at a constant temperature of 50°C for 72 hours, filter, wash, and vacuum dry to obtain modified nano-silica.

2. The thin-walled sheathed cable according to claim 1, characterized in that: The preparation method of the modified ethylene-methyl acrylate copolymer is specifically as follows: dissolving the ethylene-methyl acrylate copolymer in N-formyl dimethyl amide, adding vinyl triethoxysilane under nitrogen protection, stirring and mixing, heating to 60-70° C., dropping an initiator azobisisobutyl, and controlling the dropping of the initiator to be within 2 hours. After the dropping of the initiator is completed, stirring and reacting for 7-9 hours, adding chloroform, filtering, washing, and drying under vacuum conditions to obtain the modified ethylene-methyl acrylate copolymer.

3. The thin-walled sheathed cable according to claim 2, characterized in that: The molar ratio of ethylene-methyl acrylate copolymer to vinyl triethoxysilane is (3-8):1, and the mass of the initiator accounts for 0.1-0.3% of the total mass of vinyl triethoxysilane.

4. The thin-walled sheathed cable according to claim 1, characterized in that: The cross-linking agent is dicumyl peroxide; The nano filler is nano magnesium oxide with the surface treated by a silane coupling agent; The antioxidant was antioxidant 1010; The lubricant is calcium stearate.

5. The thin-walled sheathed cable according to claim 1, characterized in that: The halogen-free flame retardant is Fyrolflex RDP; The wear-resistant agent is PTFE micropowder; The antioxidant was antioxidant 1010; The lubricant is calcium stearate.

6. A rapid prototyping process for a thin-walled sheathed cable as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The flame retardant cross-linked polyethylene material raw material low-density polyethylene resin, modified ethylene - methyl acrylate copolymer, melamine formaldehyde resin, mixed uniformly, heated, added cross-linking agent, nano filler, antioxidant, lubricant, mixed uniformly to obtain a mixture A; S2. Extruding the mixture A outside the cable core, cooling and molding, and obtaining an insulating layer; S3. Printing code on the surface of the insulation layer; S4. The modified nylon material raw materials of nylon 6, nylon 66, maleic anhydride grafted EPDM rubber, halogen-free flame retardant, modified nano-silica, wear agent, antioxidant, lubricant according to the ratio into a high-speed mixer and mixed evenly to obtain a mixture B; S5. Extrude the mixed material B outside the insulating layer, cool and shape it to obtain a sheath, that is, a thin-walled sheathed cable.

7. The rapid prototyping process for thin-walled sheathed cables according to claim 6, characterized in that: The thickness of the sheath is 0.1-0.3 mm.

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