A method for manufacturing enameled wire for stranding bare metal conductors and then coating it.

Abstract

This invention relates to the field of enameled wire technology. To address the technical problem of uneven enamel filling and unstable surface properties caused by textures and gaps on the surface of stranded conductors, this invention provides a method for manufacturing enameled wire after stranding bare metal conductors and then coating it. The method includes the following steps: S1, annealing and softening a single-core metal conductor; S2, stranding multiple annealed conductors; S3, annealing the stranded conductors again; S4, coating the stranded conductors sequentially through a pre-heater and a post-heater. The pre-heater uses low-viscosity insulating varnish, applying it using a felt method and applying pressure to fill gaps, extending the furnace body and cyclically baking multiple times; the post-heater uses high-viscosity insulating varnish with a mold, applying it for the first four times with a slightly larger mold to adjust roundness, and then using a conventional mold for multiple more coatings and bakings. The post-heater body is shorter than the pre-heater to prevent over-baking; S5, applying lubricating oil or wax; S6, winding the finished product. This method achieves a stranded enameled wire with a dense structure, smooth surface, excellent flexibility, and superior bending resistance.

Description

Technical Field

[0001] This invention relates to the field of enameled wire technology, and more specifically to a method for manufacturing enameled wire for coating bare metal conductors after stranding. Background Technology

[0002] Enamelled wire is a type of insulated conductor commonly used in electromagnetic coils, motors, transformers, and other fields. Conventional enamelled wire typically uses a single-core metallic conductor, uniformly coated with multiple layers of insulating varnish and cured at high temperatures, resulting in good insulation properties and mechanical strength. However, in certain applications, such as electronic products used for repeatedly bent, moving parts or flexible connections, higher requirements are placed on the flexibility and bending resistance of the enamelled wire, while strict control standards are also applied to its electrical properties, particularly its resistance value. Existing conventional single-core pure copper or alloy conductor enamelled wires, due to their high rigidity and limited fatigue resistance, are insufficient to meet the reliability requirements of such products in dynamic applications.

[0003] To improve flexibility, one approach is to strand multiple thin-diameter bare metal wires together and then insulate the entire strand as a conductor. The stranded structure can significantly improve the bending flexibility of the wire. However, if ordinary single-core enameled wire is used first and then stranded, the insulating varnish layers on the surfaces of each core are isolated from each other, resulting in electrical isolation within the conductor. This leads to problems such as high overall resistance and unstable conductivity. Furthermore, if there are insulation defects in the individual wires before stranding, it may further exacerbate the risk of fluctuations in electrical performance.

[0004] Another solution is to use bare metal conductors stranded together and then directly extruded to form a composite structure with multiple layers of insulation, such as triple-insulated wire. However, the insulation thickness of this type of wire is relatively large, usually requiring an increase of about 0.150 mm or more. Taking the 0.18 mm specification as an example, the outer diameter of the finished product is 0.33 to 0.38 mm, which leads to a significant increase in the overall wire diameter, which is not conducive to the design of small-size windings. At the same time, its surface roughness is high and its smoothness is poor, which also limits its direct soldering and winding performance during processing.

[0005] Therefore, stranding bare metal conductors first, followed by coating and curing using traditional enameled wire techniques, is an ideal method that balances flexibility, bending resistance, and electrical performance. For example, a φ0.18mm single-core copper enameled wire has a resistance of approximately 0.672Ω / m. A conductor made by stranding seven φ0.068mm bare copper wires has a resistance comparable to that of a φ0.18mm single-core copper wire, while the overall conductor outer diameter is only slightly less than 0.027mm. If a standard thickness of insulating enamel layer is successfully applied, the finished wire diameter is almost identical to that of the original single-core enameled wire, effectively improving performance and avoiding excessive outer diameter.

[0006] However, traditional enameled wire manufacturing processes require extremely high surface smoothness of the conductor. The stranded conductor surface contains spiral patterns and gaps, and the high-temperature curing process after applying liquid enamel easily leads to defects such as enamel particles, enamel nodules, uneven filling, and pinholes, resulting in insufficient smoothness and affecting the product's appearance and voltage withstand performance. Furthermore, how to evenly fill the gaps with enamel and form a dense and smooth insulating layer on the outer periphery of the conductor remains a major challenge in current technology.

[0007] Therefore, there is an urgent need for a manufacturing process for stranded conductor enameled wire that can balance insulation performance, finished product smoothness, and electrical performance consistency, in order to meet the pressing demand for highly flexible and reliable enameled wires in special applications. Summary of the Invention

[0008] To address the technical problem of uneven enamel filling and unstable surface properties caused by textures and gaps on the surface of stranded conductors, this invention provides a method for manufacturing enameled wire for coating bare metal conductors after stranding.

[0009] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0010] This invention provides a method for manufacturing enameled wire for coating bare metal conductors after stranding, comprising the following steps:

[0011] S1. Annealing and softening treatment is performed on the single-core metal conductor;

[0012] S2. Twist together multiple single-core metal conductors after annealing and softening;

[0013] S3. Anneal the stranded conductors again.

[0014] S4. The stranded conductors are sequentially passed through a front furnace and a rear furnace for enameling treatment, wherein:

[0015] a) The front furnace uses a diluted insulating varnish with low viscosity and high fluidity. It is coated using the felt method, with pressure blocks added to the felt to increase pressure, so that a small amount of low viscosity varnish fills the conductor stranding gaps, and there is almost no adhesion on the outer perimeter.

[0016] b) The length of the front furnace is extended to meet the baking time required for the curing of low-viscosity paint, and multiple rounds of coating and baking processes are performed;

[0017] c) The post-furnace uses a high-concentration, high-viscosity insulating varnish of the same type for eye mold coating. When the post-furnace performs the first four coatings, the inner diameter of the varnish eye mold used is 1.04 to 1.06 times the outer diameter of the stranded conductor. This is used to fill the gaps and round the outer diameter of the stranded conductor, making the conductor more round.

[0018] d) Starting from the fifth coat of paint, the inner diameter of the paint eye mold shall be 1.09 times or more the outer diameter of the stranded conductor, for further rounding and thickening;

[0019] e) The length of the rear furnace body is shorter than that of the front furnace to prevent excessive baking damage to the insulation layer;

[0020] S5. Apply lubricating oil or wax to the surface of the enameled wire coming out of the furnace.

[0021] S6. Rewind the finished product line.

[0022] The process involves first annealing the single-core metal conductors before stranding them, followed by a second annealing to stabilize the stranded structure, ensuring conductor flexibility and consistency. The front furnace uses low-viscosity, highly fluid insulating varnish applied under pressure with felt to effectively penetrate the stranding gaps, leaving no excess varnish adhering to the outer perimeter. Combined with an extended furnace body and multiple rounds of baking, this achieves gap filling and initial surface smoothing. The rear furnace employs high-viscosity varnish and a die-casting method, rounding the conductor shape at the front and constructing a uniform and dense insulation layer at the rear. The shortened furnace length prevents over-baking of the insulation. Finally, wax or lubricant is applied to improve the finished product's smoothness. This overall process produces high-performance stranded enameled wires with a dense structure, smooth surface, stable resistance, and excellent flexibility and bending resistance, making it particularly suitable for applications requiring high insulation quality, electrical consistency, and mechanical performance.

[0023] Furthermore, the inner diameter of the coating mold used in the first four coating processes was 1.04 times, 1.04 times, 1.05 times, and 1.06 times the outer diameter of the stranded conductor, respectively. From the fifth coating onwards, the inner diameter of the coating mold was set starting at 1.09 times the outer diameter of the stranded conductor and increasing in an arithmetic progression. Using coating molds with a small multiple difference from the outer diameter of the stranded conductor in the first four coating processes helps to gradually shape and round the conductor contour in the early stages of coating, making the conductor shape more consistent, thus providing a stable benchmark for subsequent coatings. From the fifth coating onwards, using a mold inner diameter starting at 1.09 times the outer diameter and increasing in an arithmetic progression enables the insulation coating to thicken uniformly layer by layer, effectively controlling the morphology and thickness distribution of the coating layer. This avoids surface defects caused by excessively rapid coating accumulation and improves the insulation density and smoothness of the final product, ensuring the mechanical flexibility, electrical stability, and surface quality of the enameled wire.

[0024] Furthermore, the solvent ratio of the low-viscosity insulating varnish used in the pre-furnace is significantly lower than that used in conventional enameling processes. Consequently, the solid content of the insulating varnish is significantly lower than that of conventional products. Specifically, the low-viscosity, low-solids insulating varnish used in the pre-furnace has a solid content of less than 5%, while conventional varnishes have a solid content of over 15%. This significantly improves the fluidity and penetration of the varnish, making it easier to penetrate and fill the tiny gaps on the surface of the stranded conductor. This effectively avoids bubbles, voids, or insulation defects caused by insufficient filling, thereby improving the integrity and density of the insulation layer. Simultaneously, since the low-solids varnish has almost no excess adhesion to the surface of the gaps, unnecessary coating accumulation is avoided, which helps to achieve initial smoothness on the surface of the stranded conductor.

[0025] Furthermore, in the felt coating process, felt blocks are used to ensure closer contact between the conductor and the felt as the conductor passes through, thereby enhancing the penetration of the varnish. By applying blocks to the felt to increase the contact pressure between the conductor and the felt, the low-viscosity varnish can penetrate more fully into the gaps in the stranded wire, improving the adhesion and filling effect of the varnish, reducing voids, and enhancing the mechanical reliability and electrical insulation performance of the finished product.

[0026] Furthermore, the number of coating cycles in the front furnace is 8 to 10, and the number of coating cycles in the rear furnace is about 5, with 4 to 6 being preferred. Multiple cycles of coating and baking can gradually build a dense and uniform insulation layer. The front furnace achieves gap filling and preliminary shaping, while the rear furnace forms a surface coating and improves smoothness and insulation strength, giving the enameled wire both good mechanical flexibility and stable insulation performance.

[0027] Furthermore, the high-viscosity, high-solids-content insulating varnish used in the rear furnace has a solids content of 38% or more; the low-viscosity, low-solids-content insulating varnish used in the front furnace has a solids content of less than 5%.

[0028] By using low-viscosity insulating varnish with a solid content of less than 5% in the front furnace, the fine gaps on the surface of the stranded conductor can be fully penetrated and filled, achieving uniform coverage of the insulation layer inside the gaps. Meanwhile, by using high-viscosity insulating varnish with a solid content of more than 38% in the back furnace, a uniform, dense, and firmly adhered outer insulation layer can be quickly formed on the conductor surface. The combination of the two not only takes into account the permeability of the internal filling and the integrity of the outer coating, but also effectively controls the total thickness and flatness of the insulation layer, thereby significantly improving the electrical consistency, surface smoothness, and mechanical strength of the enameled wire, meeting the stringent requirements of high-performance flexible applications for insulation reliability and finished product consistency.

[0029] Furthermore, the linear speeds in the front and rear furnaces are the same, and the baking temperature range is 370°C to 390°C, preferably 390°C. Maintaining consistent linear speeds in the front and rear furnaces ensures a continuous and stable enameling process, preventing abnormal tension from causing wire deformation or insulation damage. A controlled temperature range helps the same enameled material achieve optimal curing at different stages, improving process stability and product consistency.

[0030] The beneficial effects of implementing this invention are as follows:

[0031] The method for manufacturing enameled wire for coating bare metal conductors after stranding, provided by this invention, can effectively solve technical problems such as uneven filling of varnish, unstable surface properties, and poor product consistency caused by spiral patterns and gaps on the surface of stranded conductors. By performing annealing treatments before and after conductor stranding, the flexibility and structural stability of the conductor are improved. The first coating is performed using an insulating varnish with extremely low viscosity and high solvent ratio in conjunction with a felt pressing block, which allows the varnish to penetrate smoothly and fill the gaps without accumulating on the outer surface. Combined with an extended furnace body and multiple rounds of baking, full curing and smooth transition are achieved. Subsequently, a higher viscosity insulating varnish is applied layer by layer using a mortise method to round the conductor. The slightly larger mortise in the first stage makes the wire more round, while the conventional mortise in the second stage further improves the surface smoothness and insulation strength. The overall process ensures structural density and gap filling integrity, and achieves a finished product with a round appearance, stable insulation, and good smoothness. It is especially suitable for important fields that require high flexibility, high bending resistance, resistance consistency, and insulation reliability. Attached Figure Description

[0032] Figure 1 This is a front view structural diagram of the enameled wire coating equipment of the present invention;

[0033] Figure 2 This is a three-dimensional structural diagram of the enameled wire coating equipment of the present invention;

[0034] Figure 3 This is an assembly diagram of the base, wire feeding mechanism, guide wheel 1, and annealing furnace in this invention;

[0035] Figure 4 This is an assembly diagram of the base, lubrication mechanism, and winding mechanism in this invention;

[0036] Figure 5 This is an assembly diagram of the base, felt mechanism, and front furnace in this invention;

[0037] Figure 6 This is a flowchart of the enameled wire manufacturing method in this invention.

[0038] In the diagram: 1. Base; 2. Wire feeding mechanism; 21. Mounting block one; 22. Concave block one; 23. Threaded rod one; 24. Moving block one; 25. Mounting plate one; 26. Sleeve one; 27. Unwinding roller; 3. Guide roller one; 4. Annealing furnace; 5. Guide roller two; 6. First guide roller; 7. Felt mechanism; 71. Insulating varnish coating box; 72. Fixing plate one; 73. Coating felt; 74. Material pump; 75. 8. Discharge pipe; 9. Front furnace; 10. Eye mold; 11. Rear furnace; 12. Second guide wheel; 13. Lubrication oil mechanism; 14. Lubrication oil tank; 15. Water pump; 16. Fixed plate II; 17. Pulley; 18. Oil spray pipe; 19. Winding mechanism; 10. Concave block II; 11. Threaded rod II; 12. Moving block II; 13. Mounting plate II; 14. Sleeve II; 15. Winding wheel. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] See Figure 1 and Figure 2 The present invention provides an enameling device for stranded bare metal conductors, which is provided in sequence from one side to the other, including a wire feeding mechanism 2, a first guide wheel 3, an annealing furnace 4, a second guide wheel 5, a first guide wheel 6, a felt mechanism 7, a front furnace 8, a die mold 9, a rear furnace 10, a second guide wheel 11, a lubricating oil mechanism 12, and a winding mechanism 13.

[0041] The wire feeding mechanism 2 winds stranded wire made of bare metal wire that has been annealed and softened.

[0042] See Figure 2 The wire feeding mechanism 2 includes a mounting block 21, a concave block 22, a threaded rod 23, two movable blocks 24, two mounting plates 25, two sleeves 26, and a winding wheel 27. The mounting block 21 is mounted on the top of the base 1, the concave block 22 is mounted on the mounting block 21, the threaded rod 23 is rotatably mounted in the concave block 22, and the two movable blocks 24 are symmetrically slidably mounted in the concave block 22. Both movable blocks 24 are threadedly connected to the threaded rod 23.

[0043] Two mounting plates 25 are respectively mounted on two movable blocks 24, and two sleeves 26 are respectively rotatably mounted on the outer wall of the two mounting plates 25 on the side close to each other. The unwinding wheel 27 is set between the two sleeves 26, and the two sleeves 26 are respectively adapted to the two ends of the unwinding wheel 27.

[0044] One end of the threaded rod 23 extends to one side of the concave block 22 and is fitted with a turntable 1. The guide wheel 3, the annealing furnace 4, and the guide wheel 5 are all mounted on the top of the base 1.

[0045] The front furnace 8 is installed on the top of the base 1, and two first guide wheels 6 are symmetrically installed on the front furnace 8. The felt mechanism 7 is set on the front furnace 8 and is located between the corresponding first guide wheel 6 and the front furnace 8.

[0046] See Figure 5 The felt mechanism 7 includes an insulating varnish coating box 71, a fixing plate 72, two coated felts 73, a material pump 74, and two discharge pipes 75. The insulating varnish coating box 71 and the fixing plate 72 are both installed on the front furnace 8. The fixing plate 72 is located in front of the insulating varnish coating box 71. The two coated felts 73 are symmetrically rotated and installed on the fixing plate 72. A vertical pipe is installed on the rear outer wall of the fixing plate 72. The material pump 74 is installed on the insulating varnish coating box 71. The suction pipe on the material pump 74 extends into the insulating varnish coating box 71. The injection pipe on the material pump 74 is connected to the vertical pipe. The two discharge pipes 75 are symmetrically installed on the fixing plate 72. One end of the two discharge pipes 75 is aligned with the two coated felts 73, and the other end of the two discharge pipes 75 is connected to the vertical pipe.

[0047] The rear furnace 10 is installed on the base 1, two second guide wheels 11 are symmetrically installed on the rear furnace 10, and the eye mold 9 is installed on the rear furnace 10, with the eye mold 9 located between the corresponding second guide wheel 11 and the rear furnace 10.

[0048] See Figure 4 The lubrication mechanism 12 is mounted on the base 1. The lubrication mechanism 12 includes a lubrication oil tank 121, a water pump 122, a second fixing plate 123, a pulley 124, and an oil spray pipe 125. The lubrication oil tank 121 is mounted on the base 1. The water pump 122 is mounted on the top of the lubrication oil tank 121. The second fixing plate 123 is mounted on the front outer wall of the lubrication oil tank 121. Two pulleys 124 are mounted symmetrically on the second fixing plate 123. The oil suction pipe of the water pump 122 extends into the lubrication oil tank 121. The oil discharge pipe of the water pump 122 extends to one side of the second fixing plate 123 and is aligned with the pulley 124 located above it.

[0049] The winding mechanism 13 is mounted on the base 1. The winding mechanism 13 includes a mounting block 2, a concave block 2 131, a threaded rod 2 132, two movable blocks 2 133, two mounting plates 2 134, two sleeves 2 135, and a winding wheel 136. The mounting block 2 is mounted on the top of the base 1. The concave block 2 131 is mounted on the mounting block 2. The threaded rod 2 132 is rotatably mounted on the concave block 2 131. The two movable blocks 2 133 are symmetrically slidably mounted on the concave block 2 131. Both movable blocks 2 133 are threaded with the threaded rod 2 132. The connection consists of two mounting plates 134 mounted on two movable blocks 133, two sleeves 135 rotatably mounted on the outer walls of the two mounting plates 134 on their adjacent sides, a winding wheel 136 positioned between the two sleeves 135, with both ends of the winding wheel 136 adapted to the two sleeves 135 respectively, a motor mounted on the corresponding mounting plate 134, the output shaft of the motor fixedly connected to one end of the corresponding sleeve 135, and one end of the threaded rod 132 extending to one side of the concave block 131 and mounted on a turntable 2.

[0050] See Figure 6 Based on the above-mentioned equipment, the present invention provides a method for manufacturing enameled wire after stranding bare metal conductors and then coating it with enamel. This method is suitable for improving the flexibility, surface quality and insulation performance of enameled wire, and in particular, it proposes an improved process to address the problem of difficulty in filling the gaps in the stranded structure of multi-strand metal conductors.

[0051] First, several single-core metal conductor wires are annealed and softened to improve their ductility and stranding consistency. The annealed single-core metal wires are then stranded under controlled tension and pitch to form a tightly stranded conductor. Subsequently, the stranded conductor undergoes another annealing treatment to eliminate stress generated during stranding, ensuring good structural stability during subsequent processing.

[0052] Next, the stranded conductors undergo two stages of enameling treatment: front furnace 8 and rear furnace 10. Front furnace 8 uses a felt coating method, employing a highly diluted, single-variety insulating varnish with viscosity and concentration far lower than conventional coating requirements. This varnish exhibits excellent fluidity, allowing it to penetrate and fill the tiny gaps between conductors in small amounts under the pressure of the felt. To enhance varnish penetration, pressure blocks are added to the felt to ensure full adhesion between the felt and the conductor surface, guaranteeing effective penetration of the low-viscosity varnish into the spiral grooves between the conductors. This step involves repeated coating and baking, typically requiring 8 to 10 cycles. After these cycles, the conductor gaps are gradually filled, the surface becomes smooth, and waste caused by uneven coating on the outer perimeter is effectively avoided.

[0053] Since the insulating varnish used in the front furnace 8 is low-viscosity and high-solvent-content, it is difficult to completely dry and cure at the standard process temperature (around 380°C). Therefore, this invention significantly extends the length of the front furnace 8 to prolong the heating time and improve the curing adequacy. Considering that the low-viscosity varnish is difficult to form a good coating layer on the conductor surface, further increasing the number of cycles in the front furnace 8 will not provide significant improvement. At this point, the conductor enters the rear furnace 10 section.

[0054] In the 10th section of the rear furnace, undiluted high-viscosity, high-concentration insulating varnish of the same type as that used in the 8th section of the front furnace is employed, and a die coating process is used. The initial die configuration consists of four molds, each slightly larger than the outer diameter of the stranded conductor and of uniform size. For the first four coats, the inner diameter of the die is successively 1.04, 1.04, 1.05, and 1.06 times the outer diameter of the stranded conductor. Through multiple cycles, the conductor is gradually rounded while only slightly increasing the outer diameter and varnish thickness. After the fourth die coating, subsequent die sizes are configured according to conventional enameled wire process requirements, and approximately five more rounds of coating and baking are performed to achieve the target thickness and uniformity of the enameled layer. From the fifth coat onwards, the inner diameter of the die is set starting at 1.09 times the outer diameter of the stranded conductor, increasing arithmetically. Specifically, the sixth and seventh coats are 1.12 and 1.15 times the outer diameter of the stranded conductor, respectively, and so on for subsequent coats.

[0055] Because the rear furnace 10 uses high-viscosity paint, the curing speed is faster, and the furnace length can be significantly shorter than the front furnace 8. This avoids problems such as thermal degradation or cracking of the insulating paint due to overheating. The conductor running speed is kept consistent between the front and rear furnaces 10 throughout the coating process to adapt to the curing temperature range of the same type of paint, ensuring product consistency and process controllability.

[0056] After coating, the conductor surface is further coated with lubricating oil or wax to improve its slip properties and processing compatibility, and to prevent wear or scratches to the enamel film during subsequent winding and use. Finally, the finished enameled wire is wound up by a winding device to obtain a packaged finished product.

[0057] The stranded conductor enameled wire produced by the above manufacturing method has the characteristics of small outer diameter, good flexibility, high bending resistance, and smooth and flat surface. Especially when the conductor is a highly flexible material such as copper alloy or aluminum alloy, this method can further improve its comprehensive mechanical properties on the basis of its inherent toughness. It is particularly suitable for applications with high requirements for dimensional accuracy and bending ability, such as high-frequency winding coils, flexible wires, and micro motor coils.

[0058] The beneficial effects of implementing the enameled wire manufacturing method for stranding and coating bare metal conductors provided by the present invention are as follows:

[0059] This method involves sequentially coating the stranded conductors with the same insulating varnish at low and high viscosity, combined with a front-furnace felt method and a rear-furnace eye mold method. This achieves thorough filling of the gaps in the stranded conductors and uniform outer coating, effectively solving the problems of difficult gap filling and uneven outer layer in multi-strand conductor structures. It also improves the roundness and insulation performance of the enameled wire. The front furnace extends the furnace body and uses diluted varnish with multiple cycles of curing, allowing the low-viscosity varnish to gradually fill the gaps. The rear furnace uses high-viscosity varnish to form a dense outer coating layer, effectively controlling the coating thickness and quality. The resulting enameled wire has advantages such as small outer diameter, good flexibility, high bending resistance, and smooth surface. It is especially suitable for applications with high requirements for wire forming and winding performance. Furthermore, the good density and adhesion of the varnish film are beneficial to improving the long-term electrical stability and mechanical reliability of the product.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for manufacturing an enameled wire for painting after stranding of bare metal conductors, characterized by, It comprises the following steps: S1, annealing softening treatment is carried out on single-core metal conductor; S2, the annealed softening multiple single-core metal conductor is twisted; S3, the twisted conductor is annealed again; S4, the twisted conductor is sequentially subjected to varnishing treatment in the front furnace and the rear furnace, wherein: a) the front furnace adopts insulating paint with a first concentration value and a first viscosity value, and the paint is coated by felt method, and a pressing block is additionally arranged on the felt to increase the pressure; b) the length of the front furnace is extended to meet the baking time required for curing the low-viscosity paint, and multiple tour coating and baking treatment is carried out; c) the rear furnace adopts the same type of insulating paint with a second concentration value and a second viscosity value to perform eye mold coating, the second concentration value is greater than the first concentration value, and the second viscosity value is greater than the first viscosity value, and when the first four times of coating are performed, the inner diameter of the coating eye mold used is 1.04-1.06 times the outer diameter of the twisted conductor; d) from the fifth time of coating, the inner diameter of the coating eye mold is 1.09 times the outer diameter of the twisted conductor or more; e) the length of the rear furnace is less than that of the front furnace; S5, the surface of the varnished wire coming out of the rear furnace is smeared with lubricating oil or wax; S6, the finished wire is wound; The high-viscosity high-solid-content insulating paint used in the rear furnace has a solid content of 38% or more, and the low-viscosity low-solid-content insulating paint used in the front furnace has a solid content of 5% or less.

2. A process for manufacturing enameled wire for a bare metal conductor after stranding and painting according to claim 1, characterized in that, The inner diameters of the coating eye molds used in the first four times of coating are 1.04 times, 1.04 times, 1.05 times and 1.06 times the outer diameter of the twisted conductor respectively, and from the fifth time of coating, the inner diameter of the coating eye mold is 1.09 times the outer diameter of the twisted conductor, and is set in an arithmetic progression.

3. A process for manufacturing enameled wire for a bare metal conductor after stranding and painting, according to claim 1, characterized in that, The number of coating times of the front furnace is 8-10, and the number of coating times of the rear furnace is 7-9.

4. The enameled wire manufacturing method for painting a bare metal conductor after stranding according to claim 1, characterized by, The wire speed in the front furnace and the rear furnace is the same, and the baking temperature range is 370-390℃.

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