A cable shaping and processing technology

Abstract

This invention discloses a cable shaping process, which includes the following steps: S1, arranging at least two insulated cores and two ground wires parallel to each other along the same plane, with the two ground wires located on the outermost side; S2, extruding a thermoplastic sheath over the arranged cores using an extruder to form a cable to be shaped; S3, while the sheath is not yet fully cooled and solidified, passing the cable to be shaped through at least one shaping guide wheel, the outer circumference of which has a circumferential groove, the radial cross-section of which is a trapezoid symmetrical along both sides; S4, cooling the shaped cable to obtain the finished product. This cable shaping process sets the constraint cross-section of the shaping guide wheel to a radially symmetrical trapezoidal groove and performs precise shaping during the critical process window when the sheath is in a thermoplastic state, thus systematically solving the core problems that have long existed in existing cable production, such as inaccurate ground wire positioning, difficulty in stripping, and poor cross-section control.

Description

Technical Field

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

[0002] Cables with grounding wires on both sides are special cables with symmetrically arranged grounding conductors on both sides of a flat sheath. Due to their ease of quick grounding and piercing splicing, they are widely used in intelligent buildings, security monitoring, industrial automation, and new energy fields. A typical structure involves two insulated cores arranged parallel to each other in the center, with two bare copper ground wires placed on the outermost sides. An insulating sheath is then applied over the sheath using an extrusion process, integrating the ground wires with the insulating cores. In existing production processes, after the cable sheath is extruded, it is typically shaped and its dimensions controlled by a shaping device while in a hot state. The most common method uses a shaping guide wheel with annular grooves on its outer circumference. To ensure the clamping and guiding of the flat cable, the radial cross-section of the annular grooves on existing guide wheels is generally designed as rectangular, meaning the groove walls and bottom are at right angles, the groove width equals the width of the target cable, and the groove depth corresponds to its thickness. During production, the sheath, freshly extruded from the die and in a plastic state, enters the rectangular groove. The bottom and side walls of the rectangular groove constrain the sheath surface, and it is then cooled and solidified in a water tank.

[0003] However, the production of cables with ground wires on both sides using shaping guide rollers with rectangular cross-section grooves has revealed several defects. First, the sidewalls of the rectangular groove are vertical planes, which cannot provide lateral positioning guidance for the ground wire during the extrusion and flow of the sheath. The ground wire only relies on a brief positioning at the die exit and floats in the molten sheath, making it prone to inward shifting or vertical movement during travel. This results in inconsistent ground wire positions, uncontrollable sheath thickness, and in severe cases, the ground wire may even be squeezed between the insulation cores, rendering the finished product unusable. Second, the produced cables have right-angled edges on both sides, which not only looks dull but also creates significant stress concentration at the base of the right angles when bent. After long-term use or frequent dragging, the sheath is prone to cracking at the corners, shortening the cable's service life. More importantly, because the ground wire is completely covered by the right-angled sheath, when stripping the sheath for grounding during on-site construction, the direction of the ground wire is not clearly visible, and there is a lack of reliable tearing guidance. Operators often need to use wire strippers or even blades, resulting in low stripping efficiency and a high risk of damaging the ground wire conductor or cutting the internal insulation core. Summary of the Invention

[0004] Therefore, it is necessary to provide a cable shaping process to address the technical problem that the existing cable shaping process is no longer sufficient.

[0005] A cable shaping process includes the following steps: S1. Arrange at least two insulated wire cores and two ground wires in parallel along the same plane, with the two ground wires located on the outermost side; S2. A thermoplastic sheath is extruded onto the outside of the arranged wire cores using an extruder to form a cable to be shaped; S3. Before the sheath has completely cooled and solidified, the cable to be shaped is passed through at least one shaping guide wheel. The outer circumferential surface of the shaping guide wheel is provided with a circumferential groove. The radial cross-section of the groove is a trapezoidal shape that is symmetrical along both sides of the radial direction, that is, the width of the bottom of the groove is smaller than the width of the opening of the groove, and the two sides of the groove wall are symmetrical inclined surfaces. The side walls of the trapezoidal groove are used to apply lateral constraints to the sheath, so that the two sides of the sheath are respectively formed into inclined sides that fit with the inclined surfaces, and the ground wire is positioned and constrained within the corresponding inclined sides. S4. Cool the shaped cable to obtain the finished product.

[0006] In one embodiment, the included angle between the two inclined surfaces of the trapezoidal groove of the shaping guide wheel is 20°-40°.

[0007] In one embodiment, the depth of the trapezoidal groove is equal to the total thickness of the target cable, and the width of the groove bottom is equal to the sum of the outer diameters of the two insulated cores plus the target thickness of the sheath.

[0008] In one embodiment, the shaping guide wheel is made of stainless steel or polyoxymethylene, and the groove surface is polished.

[0009] In one embodiment, the shaping guide wheel is a passive rotating wheel, which is installed in the starting section of the cooling water tank 300-500mm after the extruder die.

[0010] In one embodiment, in step S3, when the cable to be shaped passes through the shaping guide roller, the water temperature in the cooling water tank is controlled at 40-50°C.

[0011] In one embodiment, the ground wire is a bare copper wire, and the thickness of the sheath covering the ground wire at the inclined side after shaping is 0.4-0.6mm.

[0012] In one embodiment, the bottom corner and the edge of the trapezoidal groove are provided with a transition fillet with a radius of not less than 0.5 mm.

[0013] In one embodiment, after the cooling process in step S4, a step S5 is further included, in which tear grooves are pressed into the inclined sides on both sides of the sheath.

[0014] In one embodiment, the die used in step S2 to extrude the sheath is a rectangular die, the opening size of which is slightly larger than the target envelope rectangle size of the cable to be shaped.

[0015] In one embodiment, the insulated wire core and the ground wire are arranged in a parallel line in the order of "ground wire-insulated wire core-insulated wire core-ground wire" with an infinite pitch.

[0016] The aforementioned cable shaping process innovates the constraint section of the shaping guide roller from the traditional rectangular groove to a radially symmetrical trapezoidal groove. It precisely shapes the cable during the critical process window when the sheath is in a thermoplastic state, thus systematically solving the core problems that have long existed in existing cable production, such as inaccurate ground wire positioning, difficult stripping, and poor cross-section control. Because the trapezoidal groove has inclined surfaces on both sides, when the cable passes through the guide roller in a hot state, the inclined surfaces generate a directional and gentle lateral constraint force on the still-flowing sheath material. Like a mold, this simultaneously and precisely shapes both sides of the sheath into inclined sides that fit the inclined surfaces. This lateral constraint creates a "self-centering" effect, accurately and stably positioning and constraining the outermost ground wire within the corresponding inclined side, completely avoiding the defects of random ground wire position drift and uneven sheath thickness caused by the lack of lateral guidance in rectangular grooves. This invention simultaneously completes the cross-section shaping of the cable sheath and the embedding and positioning of the ground wire in one step, simplifying process control nodes. The resulting finished cable features ground wires on both sides with highly consistent spatial positions and fixed sheathing. This not only provides an ideal and predictable mating slope for subsequent piercing connectors, ensuring reliable contact, but also offers a natural guiding path and stress concentration point when the sheath needs to be stripped for grounding. This allows construction workers to easily and controllably tear open the sheath along the slope to quickly expose the ground conductor, greatly improving the efficiency and convenience of on-site grounding operations. Furthermore, the trapezoidal cross-section eliminates the sharp right angles of traditional rectangular cables, resulting in a more uniform stress distribution during bending and dragging, effectively reducing the risk of sheath cracking. This comprehensively improves the cable's structural consistency, ease of installation, and long-term service reliability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the shaping guide wheel structure in the cable shaping process of one embodiment. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, a detailed description of specific embodiments of the present invention is provided below in conjunction with the following description. 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.

[0019] 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 below, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Please see Figure 1 This invention discloses a cable shaping process, which includes the following steps: S1. Arrange at least two insulated wire cores and two ground wires in parallel along the same plane, with the two ground wires located on the outermost side; S2. A thermoplastic sheath is extruded onto the outside of the arranged wire cores using an extruder to form the cable to be shaped 1; S3. Before the sheath has completely cooled and solidified, the cable 1 to be shaped is passed through at least one shaping guide wheel 2. The outer circumferential surface of the shaping guide wheel 2 is provided with a circumferential groove. The radial cross section of the groove is a trapezoidal shape that is symmetrical along both sides of the radial direction, that is, the width of the bottom of the groove is smaller than the width of the opening of the groove, and the two sides of the groove wall are symmetrical inclined surfaces. The side walls of the trapezoidal groove are used to apply lateral constraints to the sheath, so that the two sides of the sheath are respectively formed into inclined sides that fit with the inclined surfaces, and the ground wire is positioned and constrained within the corresponding inclined sides. S4. Cool the shaped cable to obtain the finished product.

[0025] This method changes the constraint section of the shaping guide wheel 2 from a traditional rectangle to a symmetrical trapezoid. In the thermoplastic state of the sheath, the trapezoidal bevels provide directional guidance and lateral constraint to the flowing sheath material, allowing the ground wire to be precisely "pushed" and confined within the two bevels, forming a semi-embedded structure. This solves the problems of ground wire position drift and uncontrollable sheath thickness in rectangular grooves, completing cable cross-section forming and ground wire positioning in one step. The finished cable has a consistent geometry on both sides; when stripping the ground wire, the bevels provide natural tearing guidance, significantly improving the convenience of grounding operations and the reliability of connector piercing contact.

[0026] Furthermore, the included angle between the two inclined surfaces of the trapezoidal groove of the shaping guide wheel 2 is 20°-40°. By limiting the included angle of the trapezoidal inclined surfaces within this range, a suitable taper can be formed on the side of the sheath. If the included angle is too large, the lateral restraint force will be insufficient, and the ground wire will easily slip or misalign; if the included angle is too small, the inclined surface will be too tightly covered, resulting in excessively thin sheath points or even damage to the ground wire. This range balances the firmness of the ground wire's fixation with the ease of tearing the sheath when peeling it off, giving the sheath both protective strength and process-friendly characteristics.

[0027] Furthermore, the depth of the trapezoidal groove is equal to the total thickness of the target cable, and the width of the groove bottom is equal to the sum of the outer diameters of the two insulated cores plus the target thickness of the sheath. This ensures that the groove dimensions of the shaping guide roller 2 precisely correspond to the thickness of the insulated cores and the sheath of the target cable. This guarantees that the total thickness of the cable and the thickness of the main sheath portion after forming fully meet the design values, eliminating dimensional deviations. The groove bottom width precisely accommodates the insulated cores, preventing them from swaying within the groove, thereby ensuring the symmetry and consistency of the forming of the two inclined surfaces and the position of the ground wire.

[0028] Furthermore, the shaping guide wheel 2 is made of stainless steel or polyoxymethylene, and the groove surface is polished. Using stainless steel or polyoxymethylene and polishing it results in an extremely low coefficient of surface friction and excellent anti-adhesion properties. When the hot sheath passes through the groove, it will not experience dragging, tearing, or "material sticking," ensuring the smoothness of the cable surface and the precise shape of the bevel. In particular, the polyoxymethylene material also has a certain degree of self-lubrication, which can further reduce micro-scratches and improve the appearance quality of the finished product.

[0029] Furthermore, the shaping guide wheel 2 is a passive rotating wheel, installed in the initial section of the cooling water tank 300-500mm after the extruder die. The guide wheel adopts a passive rotating structure; as the cable travels, it rotates synchronously, converting sliding friction into rolling friction, fundamentally avoiding scratches on the sheath's inclined surface. Installing it 300-500mm after the die ensures the sheath material temperature is moderate, within the optimal plastic deformation window. This provides sufficient fluidity for shaping on the inclined surface while maintaining initial strength to retain the shape, resulting in the highest shaping efficiency.

[0030] Furthermore, in step S3, when the cable 1 to be shaped passes through the shaping guide roller 2, the water temperature in the cooling water tank is controlled at 40-50℃. Maintaining a gradient water temperature of 40-50℃ in the shaping section of the guide roller allows the sheath surface to rapidly "cool" and form a solidified thin shell, instantly locking the trapezoidal cross-sectional profile. This prevents the cross-section from springing back or collapsing due to gravity or traction after exiting the guide roller, and also avoids large shrinkage stress caused by overall rapid cooling. Compared to room temperature water, the cooling rate in this temperature range makes the sheath around the ground wire shrink more evenly, enhancing the sheath's grip on the ground wire.

[0031] Furthermore, the ground wire is a bare copper wire, and after shaping, the sheath covering the ground wire at the inclined side has a thickness of 0.4-0.6mm. This limits the ground wire to bare copper wire, and controls the sheath thickness at the inclined surface to 0.4-0.6mm, creating a controllable weak tear zone while ensuring effective insulation protection for the ground wire. During on-site construction, the sheath can be easily torn open along the inclined surface using only a fingernail or a simple tool to expose the ground wire, without the need for special wire strippers; wires thinner than 0.4mm may have core breakage, while those thicker than 0.6mm are difficult to strip. This range represents the optimal balance between ergonomics and protection.

[0032] Furthermore, the trapezoidal trench has rounded corners with a radius of not less than 0.5mm at both the bottom corners and the edges of the opening. These rounded corners at the trench intersections eliminate sharp edges on the trapezoidal cross-section of the cable. This fundamentally prevents sheath cracking caused by stress concentration at right angles during bending and stretching, significantly extending the cable's dynamic service life. Simultaneously, the smooth edges reduce the risk of cutting adjacent cables or workers during reeling and laying, improving safety.

[0033] Furthermore, following the cooling process in step S4, a step S5 is included where tear grooves are pressed into the inclined sides of the sheath. On the already shaped inclined surfaces of the sheath, additional tear grooves are pressed along the ground wire direction, providing a precise and linear tearing path for opening the sheath. This further reduces the tearing force required to peel off the sheath, ensuring clean tear edges that do not damage the ground wire conductor and controlling the length of the exposed ground wire, making it suitable for batch wiring of automated equipment and rapid on-site repair scenarios.

[0034] Furthermore, in step S2, a rectangular die is used for extruding the sheath, with an opening size slightly larger than the target envelope rectangle size of the cable to be shaped. Thus, a stepped forming strategy of "first roughly forming the blank, then finely shaping" is formed by using a rectangular die for pre-forming and then using a trapezoidal guide roller for final shaping. This mitigates problems such as uneven glue distribution and material flow impacting the ground wire, which could be caused by a single extrusion into a complex trapezoidal die. It also reduces die head pressure and design complexity, making the production process more stable and ensuring greater density and precision of the finished product cross-section.

[0035] Furthermore, the insulated cores and ground wire are arranged in a parallel line in the order of "ground wire-insulated core-insulated core-ground wire" with an infinite pitch. This clearly defines the arrangement order and pitch, ensuring that the insulated cores and ground wire are absolutely parallel inside the sheath, without any twisting or turning. This layout ensures that the trapezoidal cross-section of the cable is completely consistent along its length, and the ground wire is always precisely positioned at the center of the side, without fluctuating in height due to twisting. Ultimately, this guarantees a high degree of consistency in the shape of any cross-section and the coverage of the ground wire, providing perfect consistency for subsequent automated assembly and long-distance cabling.

[0036] In summary, the cable shaping process disclosed in this invention revolutionizes the constraint section of the shaping guide wheel from the traditional rectangular groove to a radially symmetrical trapezoidal groove, and performs precise shaping during the critical process window when the sheath is in a thermoplastic state. This systematically solves the core problems that have long existed in existing cable production, such as inaccurate ground wire positioning, difficult stripping, and poor cross-section control. Because the trapezoidal groove has inclined surfaces on both sides, when the cable passes through the guide wheel in a hot state, the inclined surfaces generate a directional and gentle lateral constraint force on the still fluid sheath material. Like a mold, this simultaneously and precisely shapes both sides of the sheath into inclined sides that fit the inclined surfaces. This lateral constraint creates a "self-centering" effect, accurately and stably positioning and constraining the outermost ground wire within the corresponding inclined side, completely avoiding the defects of random ground wire position drift and uneven sheath thickness caused by the lack of lateral guidance in rectangular grooves. This invention simultaneously completes the cross-section shaping of the cable sheath and the embedding and positioning of the ground wire in one step, simplifying process control nodes. The resulting finished cable features ground wires on both sides with highly consistent spatial positions and fixed sheathing. This not only provides an ideal and predictable mating slope for subsequent piercing connectors, ensuring reliable contact, but also offers a natural guiding path and stress concentration point when the sheath needs to be stripped for grounding. This allows construction workers to easily and controllably tear open the sheath along the slope to quickly expose the ground conductor, greatly improving the efficiency and convenience of on-site grounding operations. Furthermore, the trapezoidal cross-section eliminates the sharp right angles of traditional rectangular cables, resulting in a more uniform stress distribution during bending and dragging, effectively reducing the risk of sheath cracking. This comprehensively improves the cable's structural consistency, ease of installation, and long-term service reliability.

[0037] 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.

[0038] 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 cable shaping and processing technology, characterized in that, Includes the following steps: S1. Arrange at least two insulated wire cores and two ground wires in parallel along the same plane, with the two ground wires located on the outermost side; S2. A thermoplastic sheath is extruded onto the outside of the arranged wire cores using an extruder to form a cable to be shaped; S3. Before the sheath has completely cooled and solidified, the cable to be shaped is passed through at least one shaping guide wheel. The outer circumferential surface of the shaping guide wheel is provided with a circumferential groove. The radial cross-section of the groove is a trapezoidal shape that is symmetrical along both sides of the radial direction, that is, the width of the bottom of the groove is smaller than the width of the opening of the groove, and the two sides of the groove wall are symmetrical inclined surfaces. The side walls of the trapezoidal groove are used to apply lateral constraints to the sheath, so that the two sides of the sheath are respectively formed into inclined sides that fit with the inclined surfaces, and the ground wire is positioned and constrained within the corresponding inclined sides. S4. Cool the shaped cable to obtain the finished product.

2. The cable shaping and processing technology according to claim 1, characterized in that, The included angle between the two inclined surfaces of the trapezoidal groove of the shaped guide wheel is 20°-40°.

3. The cable shaping and processing technology according to claim 1, characterized in that, The depth of the trapezoidal groove is equal to the total thickness of the target cable, and the width of the groove bottom is equal to the sum of the outer diameters of the two insulated cores plus the sum of the target thickness of the sheath.

4. The cable shaping and processing technology according to claim 1, characterized in that, The shaping guide wheel is made of stainless steel or polyoxymethylene, and the groove surface is polished.

5. The cable shaping and processing technology according to claim 1, characterized in that, The shaping guide wheel is a passive rotating wheel, which is installed in the starting section of the cooling water tank 300-500mm after the extruder die.

6. The cable shaping and processing technology according to claim 1, characterized in that, In step S3, when the cable to be shaped passes through the shaping guide roller, the water temperature in the cooling water tank is controlled at 40-50℃.

7. The cable shaping and processing technology according to claim 1, characterized in that, The ground wire is a bare copper wire, and after shaping, the thickness of the sheath covering the ground wire at the inclined side is 0.4-0.6mm.

8. The cable shaping and processing technology according to claim 1, characterized in that, The trapezoidal groove has a transition fillet with a radius of not less than 0.5 mm at both the bottom corner and the edge of the groove opening.

9. The cable shaping and processing technology according to claim 1, characterized in that, After the cooling process in step S4, step S5 further includes pressing tear grooves into the inclined sides on both sides of the sheath.

10. The cable shaping and processing technology according to claim 1, characterized in that, The die used in step S2 to extrude the sheath is a rectangular die, and its opening size is slightly larger than the target envelope rectangle size of the cable to be shaped.

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