An extrusion molding die for an automobile mold
Patent Information
- Application Number
- CN202522242347.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-09-15
- Estimated Expiration
- 2035-10-23
AI Technical Summary
[0011]The beneficial effects of adopting the above-mentioned improvement scheme are as follows: The inner hole edge of the limiting support ring is set with a chamfer that matches the taper angle of the tapered guide head, so that the material can form a smooth transition contact with the chamfered surface when passing through the limiting support ring. This avoids the sudden change in flow direction caused by the right angle of the edge when the material flows through the inner hole of the support ring, reduces the generation of turbulence and eddies, and reduces the flow resistance of the material at this position. At the same time, the chamfer structure can also prevent the material from adhering and accumulating at the edge of the support ring, maintaining the unobstructed flow of the extrusion channel.
Smart Images
Figure CN224751849U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of automotive mold technology, and more specifically, relates to an extrusion molding die for automotive molds. Background Technology
[0002] In the automotive manufacturing industry, many rubber parts, plastic parts, and sealing strips are manufactured using extrusion molding. The extrusion mold, as the core equipment of this process, directly determines the molding quality of the product. Traditional extrusion molds typically employ a simple cylindrical or tapered structure with a fixed mandrel inside to form the extrusion channel. However, this structure reveals several shortcomings in practical use. Because the cross-sectional area of the extrusion channel formed between the mold cavity and the mandrel changes monotonously, the pressure distribution on the material during passage is unreasonable. Often, excessive pressure at the mold inlet damages the internal structure of the material, while insufficient pressure at the outlet results in the molded product failing to meet density requirements. Furthermore, the supports used to fix the mandrel in traditional molds... The extrusion molding process often employs right-angled reinforcing ribs or simple radial support arms. These support structures create significant flow resistance and pressure abrupt changes when materials flow through them, resulting in stagnant and eddy zones behind the support structures. This leads to uneven texture and surface defects in the extruded products at corresponding locations. Furthermore, the mandrel tip often features a flat or tapered design, causing a strong shearing effect when the material contacts the mandrel due to sudden diversion. This not only affects the plasticization quality of the material but also exacerbates the wear on the mandrel tip. After long-term use, wear on the mandrel surface and inner cavity wall causes changes in the extrusion channel dimensions, further deteriorating the stability of product quality. These technical defects limit the application of extrusion molding in the manufacturing of high-precision, high-performance automotive parts. Utility Model Content
[0003] In view of this, the present invention provides an extrusion molding die for automobile molds, which can solve the technical problems of uneven material flow during the extrusion process of existing automobile mold extrusion molding dies, resulting in inconsistent wall thickness of the molded product, loose internal structure, and easy wear of key parts of the die.
[0004] This utility model is implemented as follows:
[0005] This utility model provides an extrusion molding die for an automobile mold, comprising a mold shell, an extrusion mandrel, a limiting support ring, and a flow guiding cavity. The inner cavity of the mold shell has a tapered structure along the axial direction. The outer circumferential surface of the extrusion mandrel forms an annular extrusion channel with the inner cavity surface of the mold shell. The front end of the extrusion mandrel is provided with a tapered guide head, the taper angle of which is smaller than the taper angle of the inner cavity of the mold shell. The limiting support ring is fixedly connected to the middle section of the inner cavity of the mold shell, and the inner diameter of the limiting support ring is larger than the maximum outer diameter of the extrusion mandrel. The flow guiding cavity is disposed at the front end of the mold shell, and a confluence area is formed between the flow guiding cavity and the tapered guide head of the extrusion mandrel. The limiting support ring is fixedly connected to the inner wall of the mold shell by a number of radial reinforcing ribs, the radial reinforcing ribs being evenly distributed circumferentially, and the axial cross section of each radial reinforcing rib being streamlined.
[0006] The technical effects of the extrusion molding die for automobiles provided by this utility model are as follows: By designing the inner cavity of the die shell as a tapered structure and making the taper angle of the tapered guide head of the extrusion mandrel smaller than the taper angle of the inner cavity of the die shell, a gradually shrinking annular extrusion channel can be formed during the extrusion process, so that the material is subjected to uniformly increasing pressure when passing through, thereby achieving uniform densification of the material; at the same time, the structure of the limiting support ring fixedly connected to the die shell through radial reinforcing ribs not only ensures the concentric positioning of the extrusion mandrel, but also reduces the obstruction to the material flow through the streamlined reinforcing ribs, avoiding material stagnation and pressure sudden changes at the support structure, and improving the continuity and stability of extrusion molding.
[0007] Based on the above technical solution, the extrusion molding die for an automobile mold of this utility model can be further improved as follows:
[0008] The tapered guide head of the extrusion core rod has a smooth curved surface transition, and the front end of the tapered guide head has a rounded obtuse angle structure.
[0009] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the tapered surface of the tapered guide head adopts a smooth curved transition and is set with a rounded obtuse angle structure at the front end, which can guide the material smoothly into the annular extrusion channel, avoid stress concentration and tearing caused by sharp edges when the material contacts the front end of the extrusion mandrel, and enable the material to gradually flow along the smooth curved surface to various parts of the annular channel, reduce the internal shear stress of the material, ensure the internal uniformity of the extruded product, and prevent molding defects caused by uneven material flow.
[0010] Furthermore, the inner edge of the limiting support ring is chamfered, and the angle of the chamfer matches the taper angle of the tapered guide head of the extrusion core rod.
[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: The inner hole edge of the limiting support ring is set with a chamfer that matches the taper angle of the tapered guide head, so that the material can form a smooth transition contact with the chamfered surface when passing through the limiting support ring. This avoids the sudden change in flow direction caused by the right angle of the edge when the material flows through the inner hole of the support ring, reduces the generation of turbulence and eddies, and reduces the flow resistance of the material at this position. At the same time, the chamfer structure can also prevent the material from adhering and accumulating at the edge of the support ring, maintaining the unobstructed flow of the extrusion channel.
[0012] Furthermore, the generatrix of the inner conical structure of the mold shell is parabolic, and the radius of curvature of the parabolic generatrix gradually decreases near the discharge end.
[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: The conical structure of the inner cavity of the mold shell adopts a parabolic generatrix and the radius of curvature gradually decreases near the discharge end. This design allows the compression force on the material during the extrusion process to increase non-linearly. The relatively gentle curvature change in the first section allows the material sufficient pre-compression time, while the rapid decrease in the radius of curvature in the later section applies strong extrusion to the material before discharge. This staged pressure application method avoids the internal structural damage caused by excessive pressure in the initial stage and ensures that the material reaches the required density in the final molding stage.
[0014] Furthermore, the inner wall of the flow guiding cavity has a spiral groove structure, and the spiral angle of the spiral groove gradually increases along the axial direction.
[0015] The beneficial effects of the above-mentioned improvement scheme are as follows: The inner wall of the guide cavity is provided with a spiral groove structure with a spiral angle that gradually increases along the axial direction. This allows the material gathered in the guide cavity to be guided by the spiral groove and generate a rotational motion as it flows toward the outlet. This rotational motion can promote the mutual mixing and shearing between the layers inside the material, improve the plasticization uniformity of the material, and at the same time, the gradual increase in the spiral angle increases the rotational speed of the material, reaching the maximum rotational effect near the outlet, thereby enabling the material to obtain better flowability and filling performance at the moment of extrusion.
[0016] Furthermore, the leading edge of the streamlined cross-section of the radial stiffener is semi-elliptical, the trailing edge of the streamlined cross-section of the radial stiffener is sharply converging, and the axial length of the radial stiffener is greater than the thickness of the limiting support ring.
[0017] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: The radial reinforcing rib adopts a streamlined cross-section design with a semi-elliptical leading edge and a sharp converging trailing edge, which allows the material to be smoothly diverted along the semi-elliptical leading edge when flowing through the reinforcing rib, and quickly converged at the sharp converging trailing edge. This streamlined structure minimizes the interference of the reinforcing rib on the material flow, reduces flow resistance and pressure loss. At the same time, the design that the axial length of the reinforcing rib is greater than the thickness of the limiting support ring enhances the connection strength between the support ring and the mold shell, enabling the support ring to withstand greater radial force without deformation.
[0018] Furthermore, the gap between the extrusion mandrel and the limiting support ring is uniformly annularly distributed in the radial direction, and the width of the uniformly annularly distributed gap remains constant in the axial direction.
[0019] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the annular gap between the extrusion mandrel and the limiting support ring is maintained in a radially uniform and axially constant manner, ensuring that the material can pass through the region with a stable flow rate and uniform flow rate. This avoids the phenomenon of local material flow rate being too fast or too slow due to uneven gaps, prevents the impact of fast flow area on slow flow area, and keeps the material flow in the entire annular extrusion channel synchronized. This uniform and stable flow state plays an important role in obtaining extruded products with uniform wall thickness and accurate dimensions.
[0020] Furthermore, the outer surface of the mold shell is provided with several longitudinal heat dissipation grooves, the depth of which gradually increases along the axial direction, and the bottom of which has an arc-shaped structure.
[0021] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the longitudinal heat dissipation groove with gradually increasing depth along the axial direction and arc-shaped bottom on the outer surface of the mold shell can effectively increase the heat dissipation area of the mold shell and accelerate the transfer of heat generated during extrusion to the external environment. The axially increasing depth of the heat dissipation groove design enables stronger heat dissipation capacity in the front section of the mold where the material temperature is high, while the arc-shaped groove bottom structure avoids the stress concentration phenomenon that is easily caused by the right-angle groove bottom, improves the structural strength of the mold shell, and prevents the overall mechanical properties of the mold from being weakened due to the setting of the heat dissipation groove.
[0022] Furthermore, the extrusion mandrel is made of wear-resistant alloy steel, and the die housing is made of high-strength tool steel.
[0023] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the extrusion mandrel is made of wear-resistant alloy steel, and the mold shell is made of high-strength tool steel. The reasonable matching of the two materials ensures that the extrusion mandrel maintains its surface smoothness and dimensional accuracy under long-term material friction and scouring, and also ensures that the mold shell has sufficient strength and rigidity to resist the internal pressure and thermal stress during the extrusion process. The high hardness of the wear-resistant alloy steel makes the tapered guide head and circumferential surface of the extrusion mandrel less prone to wear, while the good toughness of the high-strength tool steel enables the mold shell to withstand long-term operation without deformation or cracking.
[0024] Furthermore, the ratio of the narrowest width of the annular extrusion channel to the maximum diameter of the inner cavity of the mold shell is in the range of 1:8 to 1:12, and the ratio of the axial length of the tapered guide head to the total length of the extrusion core rod is in the range of 1:4 to 1:6.
[0025] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By limiting the ratio of the narrowest width of the annular extrusion channel to the maximum diameter of the inner cavity of the mold shell, and the ratio of the axial length of the conical guide head to the total length of the extrusion core rod, a coordinated relationship between the key dimensions of the mold is established. The former ratio range ensures that the extrusion channel applies appropriate compression to the material, so that the internal structure of the material is not damaged due to excessive extrusion pressure caused by the channel being too narrow, nor is the material not fully compacted due to the channel being too wide. The latter ratio range ensures that the material has sufficient guiding and pre-compression area before entering the annular channel, making the pressure distribution of the entire extrusion process more reasonable and improving the stability and controllability of molding quality.
[0026] Compared with existing technologies, the advantages of the extrusion molding die for automobiles provided by this utility model are as follows: By designing the inner cavity of the die shell as a gradually tapering conical structure with a parabolic generatrix, and cooperating with the small taper angle conical guide head at the front end of the extrusion core rod, a uniformly pressure-increasing annular extrusion channel is formed between the extrusion core rod and the die shell, effectively solving the problem of uneven material flow. The limiting support ring achieves reliable positioning of the extrusion core rod through streamlined radial reinforcing ribs, while minimizing interference with material flow. The matching chamfer of the inner hole of the support ring and the constant annular gap between the core rod and the support ring further enhance the advantages. The gap further optimizes the material flow state in this area. The spiral groove structure in the guide cavity enhances the plasticization uniformity of the material. The longitudinal heat dissipation grooves on the outer surface of the shell achieve effective temperature control. The combination of wear-resistant alloy steel for the extrusion core rod and high-strength tool steel for the shell significantly improves the service life of the mold. The reasonable limitation of the ratio of each key dimension ensures the coordination of the overall structure. Compared with the prior art, this utility model can produce high-quality extruded products with uniform wall thickness, accurate dimensions, and dense internal structure. At the same time, the mold maintenance cycle is extended and the production efficiency is improved, and the overall performance is significantly improved. Attached Figure Description
[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic diagram of the structure of an extrusion molding die for an automobile.
[0029] Figure 2 This is a schematic diagram of the front end structure of the extrusion mandrel;
[0030] The attached diagram lists the components represented by each number as follows:
[0031] 10. Mold shell; 20. Extrusion mandrel; 30. Limiting support ring; 40. Flow guide cavity. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.
[0033] like Figure 1-2 The diagram shows a structural schematic of an extrusion molding die for an automobile mold provided by this utility model. The die includes a mold housing 10, an extrusion core rod 20, a limiting support ring 30, and a guide cavity 40. The inner cavity of the mold housing has a tapered structure along the axial direction. The outer circumferential surface of the extrusion core rod and the inner cavity surface of the mold housing form an annular extrusion channel. A tapered guide head is provided at the front end of the extrusion core rod, with a taper angle smaller than that of the inner cavity of the mold housing. The limiting support ring is fixedly connected to the middle section of the inner cavity of the mold housing, and the inner diameter of the limiting support ring is larger than the maximum outer diameter of the extrusion core rod. The guide cavity is located at the front end of the mold housing, forming a confluence area between the guide cavity and the tapered guide head of the extrusion core rod. The limiting support ring is fixedly connected to the inner wall of the mold housing by several radial reinforcing ribs. The radial reinforcing ribs are evenly distributed circumferentially, and the axial cross-section of each radial reinforcing rib is streamlined.
[0034] In the above technical solution, the tapered guide head of the extrusion core rod has a smooth curved transition on its tapered surface, and the front end of the tapered guide head has a rounded obtuse angle structure.
[0035] Furthermore, in the above technical solution, the inner edge of the limiting support ring is chamfered, and the angle of the chamfer matches the taper angle of the tapered guide head of the extrusion core rod.
[0036] Furthermore, in the above technical solution, the generatrix of the inner conical structure of the mold shell is parabolic, and the radius of curvature of the parabolic generatrix gradually decreases near the discharge end.
[0037] Furthermore, in the above technical solution, the inner wall of the flow guiding cavity has a spiral groove structure, and the spiral angle of the spiral groove gradually increases along the axial direction.
[0038] Furthermore, in the above technical solution, the leading edge of the streamlined cross-section of the radial stiffener is semi-elliptical, the trailing edge of the streamlined cross-section of the radial stiffener is sharply converging, and the axial length of the radial stiffener is greater than the thickness of the limiting support ring.
[0039] Furthermore, in the above technical solution, the gap between the extrusion core rod and the limiting support ring is uniformly annularly distributed in the radial direction, and the width of the uniformly annularly distributed gap remains constant in the axial direction.
[0040] Furthermore, in the above technical solution, the outer surface of the mold shell is provided with several longitudinal heat dissipation grooves, the depth of the longitudinal heat dissipation grooves gradually increases along the axial direction, and the bottom of the longitudinal heat dissipation grooves has an arc-shaped structure.
[0041] Furthermore, in the above technical solution, the extrusion mandrel is made of wear-resistant alloy steel, and the mold shell is made of high-strength tool steel.
[0042] Furthermore, in the above technical solution, the ratio of the narrowest width of the annular extrusion channel to the maximum diameter of the inner cavity of the mold shell is in the range of 1:8 to 1:12, and the ratio of the axial length of the tapered guide head to the total length of the extrusion core rod is in the range of 1:4 to 1:6.
[0043] The following is a specific embodiment 1 of this utility model: In this embodiment, the mold shell is made of H13 high-strength tool steel. The shell is cylindrical with an outer diameter of 180mm and a total length of 320mm. The inner cavity is tapered from the inlet to the outlet. The tapered structure of the inner cavity adopts a parabolic generatrix. The inner diameter at the inlet is 95mm and the inner diameter at the outlet is 38mm. The radius of curvature of the parabolic generatrix gradually transitions from 450mm in the first section to 180mm in the second section, making the shrinkage rate of the inner cavity cross-sectional area slower in the first half and faster in the second half. The extrusion core rod is made of high-chromium wear-resistant alloy steel with a total length of 280mm. The outer diameter of the rod varies at different positions. There are some changes: the outer diameter of the inlet is 70mm, the outer diameter of the middle section is 62mm, the length of the tapered guide head at the front end of the core rod is 65mm, and the taper angle of the guide head is 12°, while the equivalent taper angle of the inner cavity of the mold shell is 18 degrees. The front end of the guide head is an obtuse arc with a radius of 8mm. The entire guide head surface is precision ground to a mirror finish. The limiting support ring is made of the same H13 tool steel as the mold shell, with a thickness of 15mm and an inner diameter of 68mm. The support ring is located in the middle section of the inner cavity of the mold shell, 135mm from the inlet. The support ring and the shell are fixedly connected by 6 radial reinforcing ribs, which are spaced 60° apart circumferentially. The reinforcing ribs are evenly distributed, with each rib having a streamlined cross-section that is semi-elliptical at the leading edge (25mm major axis, 12mm minor axis) and sharply converging at the trailing edge (35° included angle). The ribs are 42mm long along the axial direction. The inner edge of the support ring is chamfered at a 45° angle with a width of 3mm. The outer diameter of the extrusion core rod at the support ring position is 62mm, forming a uniform annular gap of 3mm width between it and the inner hole of the support ring. This gap remains constant along the axial direction within a 20mm range before and after the support ring. The flow guide cavity is located at the front end of the mold shell, with an inner diameter of 42mm and a length of 55mm. The inner wall of the cavity is machined with three spiral grooves, the initial spiral angle of which is 15°. The helix angle gradually increases axially to a terminating helix angle of 35°. The groove depth is 4mm and the width is 8mm. Eight longitudinal heat dissipation grooves are machined axially on the outer surface of the mold shell. The heat dissipation grooves are evenly distributed circumferentially. The groove depth gradually increases from 5mm at the inlet end to 12mm at the outlet end. The groove width is 12mm. The bottom of the groove is an arc-shaped structure with a radius of 6mm. The width of the annular extrusion channel at its narrowest point, i.e., the outlet end, is 5mm. The ratio of this width to the maximum diameter of the mold shell cavity, 95mm, is 1:199. After calculation and adjustment, this ratio is taken as 1:190 to obtain the best extrusion effect. The ratio of the axial length of the tapered guide head, 65mm, to the total length of the extrusion core rod, 280mm, is approximately 1:4.3. Within the optimal range, the entire mold assembly underwent airtightness and dimensional accuracy testing to ensure that all fitting clearances met design requirements. This mold is used to extrude automotive door and window sealing strips, with an operating temperature set between 165 and 175°C. The material is EPDM rubber compound, which exhibits good fluidity at this temperature. The extruded sealing strip exhibits stable cross-sectional dimensions, with wall thickness deviation controlled within 0.3 mm. The product has a dense internal structure without pores and a smooth surface without flow marks. After 500 hours of continuous mold operation, inspection revealed minimal wear on the extrusion core and mold cavity, and all components functioned normally, demonstrating the rationality and practicality of this design.
[0044] The following is another specific embodiment 2 of this utility model: This embodiment 2 is based on embodiment 1, and improves the spiral groove structure of the flow guide cavity. The number of spiral grooves is increased from 3 to 5. The starting spiral angle of each groove is reduced to 10° and the ending spiral angle is increased to 40°, making the change gradient of the spiral angle greater. The groove depth remains unchanged at 4mm, but the width is reduced to 6mm. The distribution of the 5 grooves on the inner wall of the flow guide cavity is more dense, and the distance between adjacent grooves is reduced to 3mm. This improvement makes the spiral guiding effect on the material in the flow guide cavity stronger, and the rotation speed and mixing shear effect of the material are significantly enhanced. At the same time, the conical guide head of the extrusion core rod is finely adjusted, and the radius of the arc-shaped obtuse angle front end is increased from 8mm to 10mm, so that the flow diversion when the material first contacts the guide head is smoother and gentler, further reducing the shear stress of the material. The improved mold shows better plasticizing effect when extruding high viscosity rubber materials, the internal structure uniformity of the product is improved, the flow resistance of the material in the mold increases slightly but is within an acceptable range, and the overall extrusion quality is better than that of embodiment 1.
[0045] The following is another specific embodiment 3 of this utility model: This embodiment 3 is based on embodiment 1, and optimizes the radial reinforcing rib structure of the limiting support ring. The number of reinforcing ribs is increased from 6 to 8, distributed at 45° intervals along the circumference. The streamlined cross-sectional dimensions of each reinforcing rib are correspondingly reduced, the major axis of the semi-elliptical front edge is reduced to 20mm and the minor axis is reduced to 10mm, while the sharp, converging angle of the rear edge remains unchanged at 35°. The axial length of the reinforcing rib is shortened to 35mm. Increasing the number of reinforcing ribs can improve the radial support stiffness of the limiting support ring on the extrusion core rod, reducing the radial displacement of the core rod when subjected to uneven material pressure, thereby better maintaining the concentricity of the annular extrusion channel. Although the theoretical increase in the number of reinforcing ribs... While this increases the obstruction to material flow, the overall impact on material flow is comparable to that of Example 1 because the cross-sectional size of a single reinforcing rib is reduced while maintaining a streamlined design. In addition, the longitudinal heat dissipation grooves on the outer surface of the mold shell are adjusted, increasing the number of grooves from 8 to 12, reducing the width of each groove to 8 mm, and maintaining a gradient distribution of depth from 5 mm at the inlet to 12 mm at the outlet. Increasing the number of heat dissipation grooves further expands the heat dissipation area, enhancing the mold's temperature control capability during high-load continuous operation. This makes it more suitable for high-precision extrusion molding processes that require strict temperature control. The improved mold exhibits excellent dimensional stability and a longer continuous working capability when extruding automotive trim strips with complex cross-sections.
[0046] Specifically, the principle of this invention is as follows: This invention employs a combination structure of a tapered inner cavity and a guide head with a small taper angle. The spatial variation rate formed by the difference in taper angle between the two is used to control the increasing pressure on the material. When the material enters the mold, it first contacts the smooth curved surface and the obtuse-angled front end of the tapered guide head. In this area, the material experiences a gentle diversion and begins to diffuse towards both sides of the annular channel. Due to the small taper angle of the guide head, the radial diffusion speed of the material is slow, avoiding severe shear deformation. As the material continues to advance, the taper angle of the inner cavity of the mold shell becomes larger, causing the cross-sectional area of the annular channel to decrease rapidly. This accelerated contraction generates increasing extrusion pressure. The application of a parabolic generatrix makes the pressure increase exhibit a characteristic of being slow at the beginning and rapid at the end, meeting the process requirements of gradual plasticization and final strengthening and densification of the material. The setting of the limiting support ring transmits the radial force of the core rod to the outer shell wall through radial reinforcing ribs. The semi-elliptical design of the leading edge of the streamlined reinforcing ribs causes the material to be diverted when approaching the reinforcing ribs. Minimal resistance and a sharp, converging trailing edge facilitate rapid material convergence after diversion, reducing disturbance areas behind the support structure. The chamfer of the inner hole of the support ring matches the taper of the guide head, forming a continuous flow surface and eliminating abrupt changes in flow direction. A constant annular gap ensures that the material receives the same flow conditions in all circumferential positions. The spiral grooves in the guide cavity increase the mixing and shearing action within the material by inducing rotational motion, improving plasticization uniformity. The longitudinal heat dissipation grooves regulate the temperature field distribution of the mold by increasing the heat dissipation area and gradient heat dissipation capacity, ensuring that the material maintains a suitable temperature state throughout the extrusion process. The wear-resistant alloy steel core rod resists long-term erosion of the material due to its high hardness and wear resistance, while the high-strength tool steel shell maintains the structural stability of the mold with its excellent comprehensive mechanical properties. The limitation of the ratios of each dimension integrates the above technical features into a coordinated whole system, thereby achieving uniform material flow, reasonable pressure distribution, and long-life mold operation.
[0047] Before use, install the extrusion die on the die head of the extrusion equipment. Secure the die housing to the equipment flange using bolts, ensuring the axis of the extrusion mandrel is concentrically aligned with the axis of the feed screw. After installation, start the heating system to preheat the die, ensuring the die temperature reaches the required process temperature range for the material to be extruded. During preheating, the longitudinal heat dissipation grooves ensure uniform temperature distribution. Once the temperature stabilizes, start the extrusion equipment. The material enters the die cavity under the screw's push. The material first contacts the arc-shaped front end of the conical guide head, and under the guidance of the smooth curved surface, it flows outwards into the annular extrusion channel. As the material advances past the limiting support ring, the streamlined reinforcing ribs obstruct the material flow. The material flows smoothly in a constant gap. As the material continues to advance and enters the tapering section, it is subjected to gradually increasing extrusion. The parabolic inner cavity causes the pressure to increase steadily. The material rotates in the guide cavity due to the spiral grooves and is further plasticized and uniformly shaped. Finally, it is extruded from the die outlet. During the extrusion process, the screw speed and heating temperature should be adjusted appropriately according to the flow state of the material to ensure that the material passes through the die with a stable flow rate and a suitable temperature. When the die is working continuously, the longitudinal heat dissipation grooves on the outer shell can effectively dissipate heat to prevent overheating. The size and quality of the extruded products should be checked regularly. If any abnormality is found, the machine should be stopped to check whether there is material accumulation or wear of parts inside the die. After use, the heating system should be turned off and the die should be cleaned and maintained after it has cooled down naturally.
Claims
1. An extrusion molding die for an automobile mold, characterized in that, The device includes a mold shell, an extrusion mandrel, a limiting support ring, and a flow guiding cavity. The inner cavity of the mold shell has a tapered structure along the axial direction. The outer circumferential surface of the extrusion mandrel and the inner cavity surface of the mold shell form an annular extrusion channel. The front end of the extrusion mandrel is provided with a tapered guide head, the taper angle of which is smaller than the taper angle of the inner cavity of the mold shell. The limiting support ring is fixedly connected to the middle section of the inner cavity of the mold shell, and the inner diameter of the limiting support ring is larger than the maximum outer diameter of the extrusion mandrel. The flow guiding cavity is located at the front end of the mold shell, and a confluence area is formed between the flow guiding cavity and the tapered guide head of the extrusion mandrel. The limiting support ring is fixedly connected to the inner wall of the mold shell by several radial reinforcing ribs. The radial reinforcing ribs are evenly distributed along the circumference, and the axial cross-section of each radial reinforcing rib is streamlined.
2. The extrusion molding die for an automobile mold according to claim 1, characterized in that, The tapered guide head of the extrusion mandrel has a smooth curved surface transition, and the front end of the tapered guide head has a rounded obtuse angle structure.
3. The extrusion molding die for an automobile mold according to claim 2, characterized in that, The inner edge of the limiting support ring is chamfered, and the angle of the chamfer matches the taper angle of the tapered guide head of the extrusion core rod.
4. The extrusion molding die for an automobile mold according to claim 3, characterized in that, The generatrix of the inner conical structure of the mold shell is parabolic, and the radius of curvature of the parabolic generatrix gradually decreases near the discharge end.
5. The extrusion molding die for an automobile mold according to claim 4, characterized in that, The inner wall of the flow guiding cavity has a spiral groove structure, and the spiral angle of the spiral groove gradually increases along the axial direction.
6. The extrusion molding die for an automobile mold according to claim 5, characterized in that, The leading edge of the streamlined cross-section of the radial stiffener is semi-elliptical, and the trailing edge of the streamlined cross-section of the radial stiffener is sharply converging. The axial length of the radial stiffener is greater than the thickness of the limiting support ring.
7. The extrusion molding die for an automobile mold according to claim 6, characterized in that, The gap between the extrusion mandrel and the limiting support ring is uniformly annularly distributed in the radial direction, and the width of the uniformly annularly distributed gap remains constant in the axial direction.
8. The extrusion molding die for an automobile mold according to claim 7, characterized in that, The outer surface of the mold shell is provided with several longitudinal heat dissipation grooves, the depth of which gradually increases along the axial direction, and the bottom of which has an arc-shaped structure.
9. The extrusion molding die for an automobile mold according to claim 8, characterized in that, The extrusion mandrel is made of wear-resistant alloy steel, and the die housing is made of high-strength tool steel.
10. The extrusion molding die for an automobile mold according to claim 9, characterized in that, The ratio of the narrowest width of the annular extrusion channel to the maximum diameter of the inner cavity of the mold shell is in the range of 1:8 to 1:12, and the ratio of the axial length of the tapered guide head to the total length of the extrusion core rod is in the range of 1:4 to 1:6.