Elliptical extrusion mold with eccentric compensation function

Abstract

The invention discloses an elliptical extrusion mold with an eccentric compensation function. An elliptical extrusion mold with an eccentric compensation function is applied to a special cable production process, and a processing method of the elliptical extrusion mold comprises the following steps: S1, preparing a mold body blank, and determining basic size parameters of a mold body according to a special cable insulation layer forming requirement; s2, measuring and calculating eccentric compensation parameters, and calculating pre-deformation compensation parameters of the elliptical mold based on the conductor diameter of the special cable, the target thickness of an insulating layer, the melt flow characteristic of an extrusion molding material and a material deviation rule under the action of gravity. The elliptical extrusion molding die with the eccentric compensation function has the beneficial effects that uneven flowing of an extrusion molding material caused by gravity is counteracted from the source, the concentricity of a special cable insulating layer is remarkably improved, the defect that the insulating layer is eccentric due to the fact that the gravity influence is neglected during machining of a traditional die is overcome, and the production efficiency is improved. And the electrical insulation performance and the structural stability of the special cable are ensured.

Description

Technical Field

[0001] This invention belongs to the field of special cable mold processing, specifically relating to an elliptical extrusion mold with eccentric compensation function. Background Technology

[0002] The patent application, with publication number CN110920021A and subject title "An Invention Patent on a Method for Adjusting the Eccentricity of a Semi-Extrusion Tube Die for Cable Extrusion," and IPC classification number B29C48 / 30, discloses a method for "adjusting the eccentricity of a semi-extrusion tube die by using an insulating eccentricity correction tube. The insulating eccentricity correction tube has a circular annular tube at its front end, and the wall thickness of the circular annular tube is slightly less than the net distance between the core sizing area and the sleeve sizing area of ​​the semi-extrusion tube die. The specific operation steps are as follows: 1) Push the circular annular tube of the insulating eccentricity correction tube between the core sizing area and the sleeve sizing area of ​​the semi-extrusion tube die; 2) Fix the sleeve of the semi-extrusion tube die to the extruder head using a fastening tool; 3) Remove the insulating eccentricity correction tube to complete the eccentricity adjustment of the semi-extrusion tube die."

[0003] Therefore, the above-mentioned invention patents have disclosed one technical solution for adjusting the eccentricity of a semi-extrusion tube mold used for cable extrusion. However, the technical solution disclosed in the above-mentioned invention patents focuses on using an insulating eccentricity correction tube to adjust the eccentricity of the semi-extrusion tube mold, and does not further solve the problem of insulation layer eccentricity defects caused by neglecting the influence of gravity in traditional mold processing, which requires further improvement. Summary of the Invention

[0004] In view of the current situation of the prior art, the present invention overcomes the above-mentioned defects and provides an elliptical extrusion mold with eccentricity compensation function.

[0005] This invention employs the following technical solution: an elliptical extrusion mold with eccentricity compensation function, applied to the production process of special cables. The processing method of the elliptical extrusion mold includes the following steps: S1: Preparation of mold body blank, determining the basic size parameters of the mold body according to the molding requirements of special cable insulation layer; S2: Calculation of eccentricity compensation parameters. Based on the conductor diameter of the special cable, the target thickness of the insulation layer, the melt flow characteristics of the extruded material, and the material offset law under gravity, the pre-deformation compensation parameters of the elliptical die are calculated. S3: Pre-deformed structure processing: Based on the compensation parameters calculated in step S2, a pre-deformed curved surface is processed in the mold cavity of the mold body. The contour of the pre-deformed curved surface is adapted to the opposite direction of the material flow offset caused by gravity. S4: Precision finishing and assembly. The dimensions of the finished mold body are inspected and finished, mold parts are assembled, and trial operation and debugging are carried out.

[0006] As a preferred technical solution of the above technical solution, in step S1, the mold body blank is made of Cr12MoV mold steel by forging process, and after forging, it is annealed. The annealing temperature is controlled at 780-820℃ and the holding time is 3-4h.

[0007] As a preferred technical solution of the above technical solutions, in step S1, the basic dimensional parameters include the outer diameter and length of the mold body, the inlet diameter of the mold cavity and the outlet ellipse size, wherein the difference between the major axis and minor axis of the outlet ellipse size is determined to be 0.1-0.5mm according to the ellipticity requirements of the special cable insulation layer.

[0008] As a preferred technical solution of the above technical solution, the calculation of the eccentricity compensation parameter in step S2 specifically includes: establishing a gravity flow offset model of extruded material, inputting special cable extrusion process parameters and material parameters, obtaining the material offset at different positions through simulation, and then determining the concavity and convexity amplitude and extension trajectory of the pre-deformed surface.

[0009] As a preferred technical solution to the above technical solutions, in the simulation process, for the extrusion scenario of high temperature resistant special cables, an additional high temperature fluidity attenuation coefficient of the material is introduced to correct the material offset calculation results.

[0010] As a preferred technical solution to the above technical solutions, in step S3, the pre-deformed structure is processed using a five-axis linkage machining center. During the processing, diamond tools are used, the milling speed is controlled at 8000-12000 r / min, the feed rate is controlled at 50-100 mm / min, and the cutting depth per cut does not exceed 0.1 mm.

[0011] As a preferred technical solution to the above technical solutions, the tool wear is monitored in real time during the processing. When the wear exceeds 0.005mm, the tool is automatically replaced and the processed area is re-trimmed.

[0012] As a preferred technical solution of the above technical solution, in step S3, the pre-deformed surface includes an inlet transition section, a main compensation section and an outlet shaping section, wherein the inlet transition section adopts a smooth arc transition with an arc radius of 5-10mm, the concave and convex amplitude of the main compensation section is gradually distributed along the material flow direction, and the outlet shaping section has a standard elliptical contour.

[0013] As a preferred technical solution of the above technical solutions, in step S4, the dimensional accuracy detection is carried out using a coordinate measuring machine to perform full-dimensional detection on the pre-deformed surface contour, ellipse size and transition accuracy of each segment of the mold cavity, and the detection accuracy is controlled within ±0.005mm.

[0014] The elliptical extrusion mold with eccentricity compensation function disclosed in this invention has the following advantages: by calculating the pre-deformation parameters and processing the structure, it can fundamentally offset the uneven flow of extruded material caused by gravity, significantly improve the concentricity of the insulation layer of special cables, solve the eccentricity defect of the insulation layer caused by neglecting the influence of gravity in traditional mold processing, and ensure the electrical insulation performance and structural stability of special cables. Detailed Implementation

[0015] This invention discloses an elliptical extrusion mold with eccentricity compensation function. The specific implementation of this invention will be further described below with reference to the preferred embodiment (Example 1).

[0016] Example 1.

[0017] Preferably, an elliptical extrusion mold with eccentricity compensation function is used in the production process of special cables, and the processing method of the elliptical extrusion mold includes the following steps: S1: Preparation of mold body blank, determining the basic size parameters of the mold body according to the molding requirements of special cable insulation layer; S2: Calculation of eccentricity compensation parameters. Based on the conductor diameter of the special cable, the target thickness of the insulation layer, the melt flow characteristics of the extruded material, and the material offset law under gravity, the pre-deformation compensation parameters of the elliptical die are calculated. S3: Pre-deformed structure processing: Based on the compensation parameters calculated in step S2, a pre-deformed curved surface is processed in the mold cavity of the mold body. The contour of the pre-deformed curved surface is adapted to the opposite direction of the material flow offset caused by gravity. S4: Precision finishing and assembly, performing dimensional accuracy inspection and finishing on the processed mold body, assembling mold accessories and conducting trial operation and debugging; By addressing the pre-deformation parameter calculation and structural processing, the uneven flow of extruded materials caused by gravity is fundamentally offset, significantly improving the concentricity of the insulation layer of special cables. This solves the insulation layer eccentricity defect caused by neglecting the influence of gravity in traditional mold processing, ensuring the electrical insulation performance and structural stability of special cables.

[0018] In step S1, the mold body blank is prepared by forging Cr12MoV mold steel. After forging, it is annealed at a temperature of 780-820℃ for 3-4 hours. The main purpose is to eliminate forging stress. By selecting high-strength wear-resistant mold steel and using a reasonable annealing process, the mechanical properties and dimensional stability of the mold body blank are improved, the deformation risk during subsequent processing and use is reduced, the service life of the mold is extended, and it is suitable for the long-term continuous production of special cables.

[0019] In step S1, the basic dimensional parameters include the outer diameter and length of the mold body, the inlet diameter of the mold cavity, and the outlet ellipse size. The difference between the major axis and minor axis of the outlet ellipse size is determined to be 0.1-0.5mm according to the ellipticity requirements of the special cable insulation layer. The specificity of the outlet ellipse size difference ensures that the mold and the ellipse forming requirements of the special cable insulation layer are accurately matched, avoiding the problem of poor subsequent eccentricity compensation effect caused by the deviation of the basic dimensions.

[0020] In step S2, the calculation of the eccentricity compensation parameters specifically includes: establishing a gravity flow offset model for extruded materials, inputting special cable extrusion process parameters (including extrusion temperature, extrusion pressure, and traction speed) and material parameters (including melt viscosity and density), obtaining the material offset at different positions through simulation, and then determining the concavity and convexity amplitude and extension trajectory of the pre-deformed surface; by establishing a dedicated simulation model and incorporating the specific process and material parameters of special cables, the calculation of eccentricity compensation parameters becomes more accurate and targeted, avoiding the deviation of traditional empirical parameters, and ensuring that the pre-deformed structure can accurately offset the material flow offset.

[0021] In the simulation process, for the extrusion scenario of high-temperature resistant special cables, an additional high-temperature flowability attenuation coefficient of the material is introduced to correct the material offset calculation results. This is equivalent to modifying the parameters for the special working conditions of high-temperature resistant special cables, improving the adaptability of the eccentricity compensation parameters under high-temperature conditions, avoiding compensation failure caused by changes in material flow characteristics due to high temperature, and ensuring the molding quality of the insulation layer of high-temperature resistant special cables.

[0022] In step S3, the pre-deformed structure is processed using a five-axis linkage machining center. Diamond tools are used during the process, with the milling speed controlled at 8000-12000 r / min and the feed rate controlled at 50-100 mm / min. The depth of cut per cut does not exceed 0.1 mm. High-precision five-axis machining equipment and special tools are used, along with optimized machining parameters, to ensure the forming accuracy of the pre-deformed surface and avoid problems such as surface roughness and dimensional deviations during the machining process, thus ensuring the stable and reliable eccentricity compensation effect of the pre-deformed structure.

[0023] During the processing, the tool wear is monitored in real time. When the wear exceeds 0.005mm, the tool is automatically replaced and the processed area is repaired. Through real-time tool wear monitoring and timely replacement and repair, the decrease in processing accuracy caused by tool wear is avoided, the processing quality of the pre-deformed surface is further improved, the consistency of the mold cavity contour is ensured, and the stability of the concentricity of the insulation layer is guaranteed when mass-producing special cables.

[0024] In step S3, the pre-deformed surface includes an inlet transition section, a main compensation section, and an outlet shaping section. The inlet transition section adopts a smooth arc transition with a radius of 5-10mm. The concave and convex amplitude of the main compensation section is gradually distributed along the material flow direction. The outlet shaping section has a standard elliptical contour. Through the segmented pre-deformed surface, the extruded material is smoothly introduced, accurately compensated, and finally shaped, avoiding turbulence at the mold cavity inlet, reducing flow resistance, and ensuring uniform and sufficient eccentric compensation, thereby improving the smoothness and dimensional consistency of the insulation layer.

[0025] In step S4, the dimensional accuracy inspection uses a coordinate measuring machine to perform full-dimensional inspection of the pre-deformed surface contour, ellipse size, and transition accuracy of each segment of the mold cavity. The inspection accuracy is controlled within ±0.005mm. The high-precision full-dimensional inspection method ensures that the mold processing dimensions meet the requirements, promptly detects and corrects processing deviations, avoids defects in special cable products caused by unqualified molds being put into production, and improves the qualification rate of mold processing.

[0026] In step S4, the trial operation and debugging specifically includes: installing the mold onto the special cable extrusion equipment, conducting a trial extrusion test using the same extrusion materials and process parameters as in actual production, monitoring the thickness of the insulation layer in all directions in real time using an ultrasonic thickness gauge, and recording the thickness deviation data; through the trial operation and debugging simulating actual production conditions, accurately verifying the eccentricity compensation effect of the mold, obtaining thickness deviation data under real production scenarios, providing a reliable basis for possible subsequent adjustments and optimizations, and ensuring that the mold can directly adapt to actual production needs.

[0027] If the insulation layer thickness deviation obtained from the trial extrusion test exceeds ±0.01mm, the process returns to step S2 to recalculate the eccentricity compensation parameters and performs secondary processing and adjustment on the mold cavity. The cutting amount of the secondary processing is determined based on the thickness deviation data, and the single cutting amount does not exceed 0.008mm. Based on the closed-loop debugging and adjustment mechanism, the deviations that occur during the trial extrusion process are accurately corrected to avoid mold scrapping due to one-time processing deviations, reduce production costs, and ensure that the eccentricity compensation accuracy of the final mold can meet the stringent requirements of special cables.

[0028] In response to the production requirements of flexible special cables, when calculating the eccentricity compensation parameters in step S2, the flexible rebound characteristics of the insulation material are taken into account, and a rebound margin of 0.02-0.05mm is reserved for the pre-deformation compensation parameters. This is to reserve a compensation margin in combination with the rebound characteristics of the flexible special cable insulation material, so as to avoid dimensional deviations and eccentricity problems caused by rebound after the insulation layer is extruded, and ensure that the final size and concentricity of the flexible special cable insulation layer meet the requirements, thereby improving the flexibility and reliability of the product.

[0029] The processing method of the elliptical extrusion mold further includes step S5: mold surface protection treatment, spraying a high-temperature resistant and anti-corrosion coating on the outer surface of the mold body, the coating thickness is 0.05-0.1mm, and the coating material is polytetrafluoroethylene modified coating; through the outer surface protective coating treatment, the high temperature resistance and anti-corrosion performance of the mold are improved, adapting to the complex environment of the special cable production workshop, reducing the erosion of the mold body by environmental factors, extending the service life of the mold, and facilitating the cleaning and maintenance of the mold.

[0030] In step S2, the calculation of the eccentricity compensation parameter also incorporates a mold processing error coefficient. The processing error coefficient is determined based on the accuracy level of the selected processing equipment and has a value range of 1.02-1.05. By introducing the processing error coefficient, deviations caused by the accuracy of the processing equipment can be avoided in advance, making the calculated eccentricity compensation parameter more practical and ensuring that the finished mold can accurately achieve the eccentricity compensation effect, thereby improving the first-pass yield of mold processing.

[0031] Specifically, to meet the production needs of special cables for extreme environments such as deep sea and high-altitude cold regions, a temperature regulation channel is set in the mold cavity of the mold body. The mold cavity temperature is precisely controlled by circulating temperature control medium with a temperature control accuracy of ±1℃. The influence factor of temperature on material flow characteristics is incorporated into the calculation of the eccentricity compensation parameters. This enables precise control of the mold cavity temperature in extreme environments. With the help of targeted compensation parameter calculations, it ensures that the extruded material can maintain stable flow characteristics under extreme working conditions, guarantee the eccentricity compensation effect and molding quality of the insulation layer, expand the applicability of the mold, and meet the stringent production requirements of special cables for extreme environments.

[0032] The temperature regulating channel is spirally wrapped around the mold cavity of the mold body. The diameter of the temperature regulating channel is 3-5mm. The temperature control medium is heat-conducting oil. The spiral wrapping ensures uniform temperature distribution in the mold cavity and avoids uneven material flow caused by local temperature deviations.

[0033] It is worth mentioning that the specific structure and other technical features of the ultrasonic thickness gauge involved in this patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement of these technical features can be conventionally selected in the field and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0034] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. An elliptical extrusion mold with eccentricity compensation function, characterized in that, The processing method of the elliptical extrusion mold, applied to the production process of special cables, includes the following steps: S1: Preparation of mold body blank, determining the basic size parameters of the mold body according to the molding requirements of special cable insulation layer; S2: Calculation of eccentricity compensation parameters. Based on the conductor diameter of the special cable, the target thickness of the insulation layer, the melt flow characteristics of the extruded material, and the material offset law under gravity, the pre-deformation compensation parameters of the elliptical die are calculated. S3: Pre-deformed structure processing: Based on the compensation parameters calculated in step S2, a pre-deformed curved surface is processed in the mold cavity of the mold body. The contour of the pre-deformed curved surface is adapted to the opposite direction of the material flow offset caused by gravity. S4: Precision finishing and assembly. The dimensions of the finished mold body are inspected and finished, mold parts are assembled, and trial operation and debugging are carried out.

2. The elliptical extrusion mold with eccentricity compensation function according to claim 1, characterized in that, In step S1, the mold body blank is made of Cr12MoV mold steel by forging process, and then annealed after forging. The annealing temperature is controlled at 780-820℃ and the holding time is 3-4h.

3. The elliptical extrusion mold with eccentricity compensation function according to claim 1, characterized in that, In step S1, the basic dimensional parameters include the outer diameter and length of the mold body, the inlet diameter of the mold cavity, and the outlet ellipse size. The difference between the major axis and minor axis of the outlet ellipse size is determined to be 0.1-0.5 mm according to the ellipticity requirements of the special cable insulation layer.

4. The elliptical extrusion mold with eccentricity compensation function according to claim 1, characterized in that, In step S2, the calculation of the eccentricity compensation parameters specifically includes: establishing a gravity flow offset model of extruded material, inputting special cable extrusion process parameters and material parameters, obtaining the material offset at different positions through simulation, and then determining the concavity and convexity amplitude and extension trajectory of the pre-deformed surface.

5. The elliptical extrusion mold with eccentricity compensation function according to claim 4, characterized in that, In the simulation process, for the extrusion scenario of high-temperature resistant special cables, an additional high-temperature fluidity attenuation coefficient of the material is introduced to correct the material offset calculation results.

6. The elliptical extrusion mold with eccentricity compensation function according to claim 1, characterized in that, In step S3, the pre-deformed structure is processed using a five-axis linkage machining center. Diamond tools are used during the processing, the milling speed is controlled at 8000-12000 r / min, the feed rate is controlled at 50-100 mm / min, and the cutting depth per cut does not exceed 0.1 mm.

7. The elliptical extrusion mold with eccentricity compensation function according to claim 6, characterized in that, The tool wear is monitored in real time during the machining process. When the wear exceeds 0.005mm, the tool is automatically replaced and the machined area is re-trimmed.

8. The elliptical extrusion mold with eccentricity compensation function according to claim 1, characterized in that, In step S3, the pre-deformed surface includes an inlet transition section, a main compensation section, and an outlet shaping section. The inlet transition section adopts a smooth arc transition with a radius of 5-10 mm. The concave and convex amplitudes of the main compensation section are gradually distributed along the material flow direction. The outlet shaping section has a standard elliptical contour.

9. The elliptical extrusion mold with eccentricity compensation function according to claim 1, characterized in that, In step S4, the dimensional accuracy detection is performed using a coordinate measuring machine to detect the pre-deformed surface contour, ellipse size, and transition accuracy of each segment of the mold cavity in all dimensions, with the detection accuracy controlled within ±0.005mm.