A thin cable processing technology

Abstract

This invention discloses a thin cable processing technology, which includes the following steps: S1, feeding two conductors parallel into an extruder head and co-extruding thermoplastic insulating material to form a flat wire blank covering the two conductors; S2, after extrusion and before cooling and setting, passing the still-hot wire blank through a set of pressure roller shaping devices, which includes at least a pair of pressure rollers arranged vertically and horizontally, the axes of the pressure rollers being parallel to the cable travel direction and perpendicular to the cable width direction, the upper and lower pressure rollers applying pressure to each other along the thickness direction of the wire blank, calendering and thinning the wire blank to a preset finished thickness; S3, subsequently cooling and setting the wire blank. This thin cable processing technology utilizes the high plasticity of the insulating material at high temperatures, and through the active mechanical calendering of the pressure rollers, the thickness of the wire blank can be directly and precisely controlled to the finished product size.

Description

Technical Field

[0001] This invention relates to the field of cable processing technology, and in particular to a thin cable processing technology. Background Technology

[0002] Thin dual-conductor cables, such as dual-core parallel flat cables, transparent speaker cables, and LED strip connection cables, are widely used in consumer electronics, smart homes, and automotive lighting due to their ultra-thin, flexible, and easy-to-install characteristics. A typical structure of this type of cable consists of two round conductors arranged parallel to each other at a certain center distance, covered by a common thermoplastic insulation layer, forming a flat cross-section. Its thickness is usually much smaller than its width. Currently, the mainstream manufacturing process for such thin dual-conductor flat cables is as follows: the two conductors are fed parallel to each other into a single-screw extruder head through a guiding device, and molten insulation material is co-extruded using a die with a flat exit to form a flat wire blank covering the conductors. The wire blank is then cooled in a water bath, and its cross-sectional shape is maintained during travel by sizing guide rollers or shaping rollers. Finally, it is wound up by a traction device and a take-up device. In this process, the final size and shape of the cable mainly depend on the geometry of the extrusion die, the mechanical constraints of the guide rollers, and the cooling conditions.

[0003] However, the aforementioned traditional processes, in their pursuit of thinner and higher precision, have revealed the following significant shortcomings: First, it is difficult to overcome the technological limits of ultra-thin forming. When the finished product thickness is required to be below 1.5 mm and the insulation wall thickness is below 0.3 mm, the cross-sectional area of ​​the flow channel inside the flat die decreases sharply, and the melt flow resistance increases dramatically, easily causing problems such as uneven material output, surface flow marks, insufficient adhesive, or even exposed conductors. Relying solely on the natural extrusion molding of the die shape, the dimensional tolerance of the finished product thickness can usually only be controlled within ±0.1 mm, and it is very easy to exhibit wavy fluctuations in the thickness direction, making it difficult to meet the micron-level precision requirements of precision cables. Second, conductor eccentricity and structural asymmetry are serious problems. During the extrusion of molten insulation material into the cooling water tank, due to the influence of material fluidity, gravity settling, and water flow disturbance, the two conductors are very likely to deviate from the ideal parallel position, resulting in vertical misalignment or changes in horizontal spacing. Traditional guide rollers primarily act on the sides or localized areas of the upper surface of the cable, failing to provide uniform and symmetrical constraint on the entire wire blank in the thickness direction. Therefore, they struggle to fundamentally correct and prevent conductor eccentricity, leading to inconsistent electrical parameters such as capacitance and inductance between the two conductors, thus affecting high-frequency signal transmission performance. Third, surface quality and appearance are poor. Existing sizing guide rollers typically have point or line contact with the cable surface, easily leaving scratches, indentations, or friction marks under high speeds and temperatures. Simultaneously, due to differences in melt stretching and cooling contraction caused by the extrusion die, the cable surface often exhibits defects such as streaks and orange peel, requiring additional grinding or trimming, reducing yield and production efficiency. Fourth, flexibility in specification changes is poor, and changeover costs are high. In traditional processes, cable thickness is directly determined by the extrusion die gap. When changing the finished product thickness, the entire extrusion die set, or even the die head assembly, must be replaced, requiring lengthy temperature balancing and adjustments. This not only increases tooling costs but also leads to significant material waste and downtime, making it difficult to adapt to the flexible production needs of diverse varieties and small batches. Besides the traditional methods mentioned above, some technologies attempt to add cold-pressing rollers after cooling to flatten the cables. However, since the insulation material has completely solidified and lost its plasticity at this point, cold pressing can only play a localized finishing role and cannot fundamentally change the thickness and structural symmetry. Another method, stretching and thinning, easily leads to a thinner conductor diameter and uneven insulation layer, resulting in a decrease in electrical and mechanical strength.

[0004] In summary, existing technologies lack a processing method that can precisely control the thickness of thin double-conductor cables, significantly improve the positional symmetry and surface quality of the double conductors, and offer high dimensional flexibility. Therefore, there is an urgent need in the field for a new manufacturing process to overcome these shortcomings. Summary of the Invention

[0005] Therefore, it is necessary to provide a thin cable processing technology to address the technical problem of insufficient accuracy in controlling cable thickness in existing cable manufacturing processes.

[0006] A thin cable processing technology includes the following steps: S1. Two conductors are fed into the extruder head in parallel and co-extruded thermoplastic insulating material to form a flat wire blank covering the two conductors; S2. After extrusion molding and before cooling and shaping, the still hot wire blank is passed through a set of pressure roller shaping device, which includes at least a pair of pressure rollers arranged facing each other, the axis of the pressure rollers being parallel to the direction of cable travel and perpendicular to the direction of cable width, the upper and lower pressure rollers applying pressure to each other along the thickness direction of the wire blank to roll and thin the wire blank to the preset finished thickness. S3. The wire rod is then cooled and shaped.

[0007] In one embodiment, the pressure roller shaping device includes multiple pairs of upper and lower pressure rollers arranged sequentially along the travel direction, with the gap between the multiple pairs of pressure rollers decreasing step by step.

[0008] In one embodiment, the pressure roller shaping device includes three pairs of upper and lower pressure rollers, the gap between the first pair of pressure rollers is 1.3 to 1.8 times the thickness of the finished product, the gap between the second pair of pressure rollers is 1.1 to 1.2 times the thickness of the finished product, and the gap between the third pair of pressure rollers is equal to the thickness of the finished product.

[0009] In one embodiment, in step S2 above, a circulating cooling medium is provided inside the pressure roller to maintain the roller surface temperature between 30 and 60°C.

[0010] In one embodiment, in step S2 above, the gap between the upper and lower pressure rollers is adjusted by a servo motor driving the upper roller to rise and fall via a precision screw mechanism, with an adjustment accuracy of ±0.01mm.

[0011] In one embodiment, the pressure roller shaping device is further equipped with a pressure sensor for real-time monitoring of the roller pressure applied to the wire blank and for issuing an alarm when the pressure exceeds a set limit.

[0012] In one embodiment, in step S1 above, the two conductors are preheated before being fed into the extruder head.

[0013] In one embodiment, in step S3 above, the cooling and shaping process uses a stepped warm water bath, with the water temperature gradually decreasing from the 40°C area to the room temperature area.

[0014] In one embodiment, the thin cable processing technology further includes step S4: after cooling and shaping, the cable thickness is measured online by laser, and the measurement signal is fed back to the gap adjustment system of the pressure roller to form a closed-loop control of the finished product thickness.

[0015] In one embodiment, the surface roughness Ra of the pressure roller is ≤0.2μm, and a spraying device for applying a release agent to the surface of the pressure roller is provided on the inlet side of the pressure roller.

[0016] In one embodiment, the width of the upper and lower pressure rollers is 40-60 mm wider than the finished width of the cable.

[0017] The aforementioned thin cable processing technology utilizes the high plasticity of insulating materials at high temperatures. Through active mechanical calendering by pressure rollers, the thickness of the wire blank can be precisely controlled to the finished product size. This breaks through the limitations of traditional dies in stably forming ultra-thin flat cross-sections, allowing the insulation layer thickness to be as low as 0.2 mm with significantly narrowed thickness tolerances, achieving micron-level precision. Secondly, the upper and lower pressure rollers synchronously and uniformly press along the thickness direction, forcing the insulating melt to flow orderly and fill systematically in the width direction. This fundamentally eliminates conductor eccentricity caused by gravity settling or uneven flow channels, substantially improving the structural symmetry and center distance stability of the two conductors, significantly ensuring the consistency of the cable's electrical performance. Thirdly, the wire blank undergoes surface cooling and shaping under the uniformly distributed constraint force applied by the pressure rollers. Its surface precisely replicates the smooth working surface of the pressure rollers, forming a dense, smooth, and flat skin. This eliminates surface defects such as extrusion die streaks, flow marks, and scratches and indentations caused by traditional guide rollers, achieving a high-quality appearance without subsequent grinding or trimming. Meanwhile, this method replaces chemical shaping, which relies on die size, with mechanical calendering for sizing. Product thickness can be flexibly changed simply by adjusting the roller gap, allowing a single extrusion die to cover the production of multiple specifications, greatly improving process compatibility and changeover efficiency. Furthermore, hot calendering further compacts and orienteds the insulation material, eliminating micropores and effectively reducing internal shrinkage, thus enhancing the cable's mechanical strength and insulation density. In summary, this solution achieves high-precision, high-surface-quality, and highly efficient flexible production of thin double-conductor cables in a simple and reliable manner. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the pressure roller shaping device in a thin cable processing technology of one embodiment. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0025] Please see Figure 1 This invention discloses a thin cable processing technology, which includes the following steps: S1. Two conductors are fed into the extruder head in parallel and co-extruded thermoplastic insulating material to form a flat wire blank 1 covering the two conductors; S2. After extrusion molding and before cooling and shaping, the still hot wire blank 1 is passed through a set of pressure roller shaping device, which includes at least a pair of pressure rollers 2 arranged facing each other. The axis of the pressure rollers 2 is parallel to the direction of cable travel and perpendicular to the direction of cable width. The upper and lower pressure rollers 2 apply pressure to each other along the thickness direction of the wire blank 1 to roll and thin the wire blank 1 to the preset finished thickness. S3. Then, the wire rod 1 is cooled and shaped.

[0026] This solution utilizes opposing upper and lower pressure rollers 2 for active calendering and shaping. This solution can directly and precisely control the cable thickness, overcoming the limitations of traditional molds in forming ultra-thin flat structures; at the same time, the symmetrical pressure from the upper and lower parts can eliminate conductor eccentricity caused by gravity or uneven flow channels, making the positions of the two conductors more symmetrical, and significantly improving surface flatness and dimensional consistency.

[0027] Furthermore, the pressure roller shaping device includes multiple pairs of upper and lower pressure rollers 2 arranged sequentially along the travel direction, with the gap between the multiple pairs of pressure rollers 2 decreasing progressively. This allows the molten insulating material to undergo a gradual deformation process of "rough pressing – fine pressing – shaping." This avoids material accumulation, bubbles, or surface tearing caused by a single large deformation, while also ensuring the orderly orientation of molecular chains, improving the mechanical strength and surface fineness of the cable, and further improving thickness uniformity.

[0028] Furthermore, the pressure roller shaping device includes three pairs of upper and lower pressure rollers 2. The gap between the first pair of pressure rollers 2 is 1.3 to 1.8 times the thickness of the finished product, the gap between the second pair of pressure rollers 2 is 1.1 to 1.2 times the thickness of the finished product, and the gap between the third pair of pressure rollers 2 is equal to the thickness of the finished product. This divides the calendering process into three stages: preliminary thinning, precise thinning, and final sizing. This parameter combination allows the insulating material to be fully expanded and evenly filled around the conductor, ensuring that the conductor is not damaged and achieving a smooth surface texture and precise finished product thickness at the last pair of rollers, with dimensional tolerances stable within ±0.05mm.

[0029] Furthermore, in step S2 above, a circulating cooling medium is circulated inside the pressure roller 2 to maintain the roller surface temperature between 30 and 60°C. By circulating the cooling medium inside the pressure roller 2 and controlling the surface temperature at 30-60°C, a dense and glossy cooling layer is quickly formed on the hot insulating skin upon contact with the pressure roller 2. This thins the skin while fixing its shape, effectively preventing shrinkage, bending, and other deformations during subsequent cooling, and eliminating die marks.

[0030] Furthermore, in step S2 above, the gap between the upper and lower pressure rollers 2 is adjusted by a servo motor driving the upper roller to rise and fall via a precision screw mechanism, with an adjustment accuracy of ±0.01mm. This embodiment uses a servo motor in conjunction with a precision screw to drive the upper roller to rise and fall to adjust the gap of the pressure rollers 2, achieving an accuracy of ±0.01mm, thus enabling digital, micron-level control of thickness adjustment. This not only ensures a high degree of consistency in thickness during continuous production but also allows the same set of pressure rollers 2 to adapt to products of different thicknesses simply by changing the gap parameters, significantly improving production flexibility and changeover efficiency.

[0031] Furthermore, the pressure roller shaping device is also equipped with a pressure sensor to monitor the roller pressure applied by the pressure roller 2 to the wire blank 1 in real time, and to issue an alarm when the pressure exceeds the set limit. This embodiment introduces real-time pressure monitoring and over-limit alarm, which can detect whether the extrusion pressure of the pressure roller 2 is abnormal online, thereby effectively preventing excessive pressure caused by incorrect gap setting, material fluctuations, or conductor misalignment. If the pressure is too high, it can be adjusted in time to avoid quality accidents such as conductor flattening, insulation thinning, or even breakdown, and to ensure the roundness and electrical performance of the conductor.

[0032] Furthermore, in step S1 above, the two conductors are preheated before being fed into the extruder head. Preheating the conductors before they enter the die head increases the interface temperature between the conductor and the molten insulation material, increases the wettability and adhesion of the insulation to the conductor, and prevents the insulation from peeling off from the conductor during subsequent large deformation rolling, thereby ensuring the structural integrity and service life of the thin cable under repeated bending.

[0033] Furthermore, in step S3 above, the cooling and shaping process employs a stepped warm water bath, with the water temperature gradually decreasing from 40°C to room temperature. This stepped cooling from 40°C to room temperature significantly reduces the temperature gradient between the inside and outside of the insulation layer and the internal stress caused by cooling. This effectively suppresses longitudinal bending, lateral curling, and surface micro-cracks common in thin cables, ensuring the finished product remains flat and flexible, thus improving appearance and coil quality.

[0034] Furthermore, the thin cable processing technology also includes step S4: after cooling and shaping, the cable thickness is measured online using laser technology, and the measurement signal is fed back to the gap adjustment system of the pressure roller 2, forming a closed-loop control of the finished product thickness. This embodiment achieves fully closed-loop automatic control through online laser thickness measurement and feedback to the gap adjustment system of the pressure roller 2. This allows for real-time compensation for thickness drift caused by fluctuations in insulation material temperature and changes in traction speed, further reducing thickness deviation and achieving ultra-high precision production without human intervention, thus improving yield.

[0035] Furthermore, the surface roughness Ra of the pressure roller 2 is ≤0.2μm, and a spraying device for applying a release agent to the surface of the pressure roller 2 is provided on the inlet side of the pressure roller 2. This embodiment controls the surface roughness of the pressure roller 2 to a mirror-like level of Ra≤0.2μm, and supplements it with a small amount of release agent spray, which fundamentally prevents the adhesion of high-temperature insulating material to the surface of the pressure roller 2. This ensures that the cable surface is free from scratches and pitting during continuous high-speed production, maintains a mirror-like effect, reduces downtime for cleaning, and improves the effective operating rate of the equipment.

[0036] Furthermore, the width of the upper and lower pressure rollers 2 is 40-60mm wider than the finished width of the cable. This ensures that the width of the pressure rollers 2 is 40-60mm greater than the finished width of the cable, guaranteeing that both edges of the cable in the width direction are uniformly and fully rolled and constrained. This avoids missing material or burrs at the edges, making the width dimension of the thin cable more stable and the sides neater, eliminating the need for subsequent edge trimming processes, and improving yield and appearance quality.

[0037] In summary, the thin cable processing technology disclosed in this invention utilizes the high plasticity of insulating materials at high temperatures. Through active mechanical calendering by pressure rollers, the thickness of the wire blank can be directly and precisely controlled to the finished product size. This breaks through the technological limit of traditional dies, which struggle to stably form ultra-thin flat cross-sections, allowing the insulation layer thickness to be as low as 0.2 mm with significantly narrowed thickness tolerances, achieving micron-level precision. Secondly, the upper and lower pressure rollers synchronously and uniformly press along the thickness direction, forcing the insulating melt to flow orderly and fill systematically in the width direction. This fundamentally eliminates conductor eccentricity caused by gravity settling or uneven flow channels, substantially improving the structural symmetry and center distance stability of the two conductors, significantly ensuring the consistency of the cable's electrical performance. Thirdly, the wire blank undergoes surface cooling and shaping under the uniformly distributed constraint force applied by the pressure rollers. Its surface layer precisely replicates the smooth working surface of the pressure rollers, forming a dense, smooth, and flat skin. This eliminates surface defects such as extrusion die streaks, flow marks, and scratches and indentations caused by traditional guide rollers, achieving a high-quality appearance without subsequent grinding or trimming. Meanwhile, this method replaces chemical shaping, which relies on die size, with mechanical calendering for sizing. Product thickness can be flexibly changed simply by adjusting the roller gap, allowing a single extrusion die to cover the production of multiple specifications, greatly improving process compatibility and changeover efficiency. Furthermore, hot calendering further compacts and orienteds the insulation material, eliminating micropores and effectively reducing internal shrinkage, thus enhancing the cable's mechanical strength and insulation density. In summary, this solution achieves high-precision, high-surface-quality, and highly efficient flexible production of thin double-conductor cables in a simple and reliable manner.

[0038] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A thin cable processing technology, characterized in that, Includes the following steps: S1. Two conductors are fed into the extruder head in parallel and co-extruded thermoplastic insulating material to form a flat wire blank covering the two conductors; S2. After extrusion molding and before cooling and shaping, the still hot wire blank is passed through a set of pressure roller shaping device, which includes at least a pair of pressure rollers arranged facing each other, the axis of the pressure rollers being parallel to the direction of cable travel and perpendicular to the direction of cable width, the upper and lower pressure rollers applying pressure to each other along the thickness direction of the wire blank to roll and thin the wire blank to the preset finished thickness. S3. The wire rod is then cooled and shaped.

2. The thin cable processing technology according to claim 1, characterized in that, The pressure roller shaping device includes multiple pairs of upper and lower pressure rollers arranged sequentially along the travel direction, with the gap between the multiple pairs of pressure rollers decreasing step by step.

3. The thin cable processing technology according to claim 2, characterized in that, The pressure roller shaping device includes three pairs of upper and lower pressure rollers. The gap between the first pair of pressure rollers is 1.3 to 1.8 times the thickness of the finished product, the gap between the second pair of pressure rollers is 1.1 to 1.2 times the thickness of the finished product, and the gap between the third pair of pressure rollers is equal to the thickness of the finished product.

4. The thin cable processing technology according to claim 1, characterized in that, In step S2 above, a circulating cooling medium is circulated inside the pressure roller to maintain the roller surface temperature between 30 and 60°C.

5. The thin cable processing technology according to claim 1, characterized in that, In step S2 above, the gap between the upper and lower pressure rollers is adjusted by a servo motor driving the upper roller to rise and fall via a precision screw mechanism, with an adjustment accuracy of ±0.01mm.

6. The thin cable processing technology according to claim 5, characterized in that, The pressure roller shaping device is also equipped with a pressure sensor to monitor the roller pressure applied to the wire blank in real time and to issue an alarm when the pressure exceeds the set limit.

7. The thin cable processing technology according to claim 1, characterized in that, In step S1 above, the two conductors are preheated before being fed into the extruder head.

8. The thin cable processing technology according to claim 1, characterized in that, In step S3 above, the cooling and shaping process uses a stepped warm water bath, with the water temperature gradually decreasing from the 40°C range to the room temperature range.

9. The thin cable processing technology according to claim 1, characterized in that, The thin cable processing technology also includes step S4: after cooling and shaping, the cable thickness is measured online by laser, and the measurement signal is fed back to the gap adjustment system of the pressure roller to form a closed-loop control of the finished product thickness.

10. The thin cable processing technology according to claim 1, characterized in that, The surface roughness of the pressure roller is Ra≤0.2μm, and a spraying device for applying release agent to the surface of the pressure roller is provided on the inlet side of the pressure roller.

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