CN108421898B

CN108421898B - Conformal cooling pipeline mold with internal threads and manufacturing method thereof

Info

Publication number: CN108421898B
Application number: CN201810373039.6A
Authority: CN
Inventors: 盈亮; 高天涵; 戴明华; 胡平; 韩啸
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2018-04-24
Filing date: 2018-04-24
Publication date: 2024-05-03
Anticipated expiration: 2038-04-24
Also published as: CN108421898A

Abstract

The invention provides a conformal cooling pipeline die with internal threads and a manufacturing method thereof, wherein the structure is as follows: the shape of the cooling pipeline in the die is the same as or similar to the shape of the processing surface of the die, namely, the cooling pipeline has curvature distribution which is the same as or similar to the shape of the die surface, the inner wall of the cooling pipeline is provided with a convex thread tooth mouth, the diameter of the cooling pipeline, the cross-sectional shape and the size of the threads, the thread pitch value and the distance between the pipelines are obtained optimally according to the cooling temperature field of the die surface, and the cooling pipeline is related to actual production process parameters; the conformal cooling pipeline mold with the internal threads is manufactured by sequentially embedding a mold matrix part and a mold embedded conformal cooling pipeline part through a selective laser deposited metal 3D printing technology. The invention has the advantages of high cooling efficiency, good uniformity, good quality of part products, high die manufacturing precision, low cost, good manufacturing environment and the like, and the technology can be widely applied to the related industries such as injection molding, hot stamping and the like.

Description

Conformal cooling pipeline mold with internal threads and manufacturing method thereof

Technical Field

The invention relates to the related fields of injection molding, hot stamping and the like, in particular to a conformal cooling pipeline mold with internal threads and a manufacturing method thereof.

Background

The metal mould is a tool for processing and forming parts in the manufacturing industry, is widely applied to the fields of stamping, die casting, die forging, injection molding, blow molding and the like, and is known as a master of the industry. The structure and the manufacturing precision of the die are the problems focused on the current die design, and in the field of hot working, the heat dissipation capacity of the die is important to the quality of the obtained part, and particularly, the heat dissipation efficiency of the workpiece in the hot working process and the injection molding of plastic products are high and low, and the heat dissipation uniformity directly influences the quality and the production efficiency of the products. At present, the cooling mode of a hot working die is mainly to add a cooling pipeline in the die, take away the heat of the die by using modes such as liquid, gas and the like, force the die to cool down, and the inner wall of the cooling pipeline is mostly of a smooth and convex-concave-free structure due to machining limitation. However, it is difficult to further enhance the heat dissipation capability of the mold by such a cooling pipe having smooth inner walls and no projections and depressions. If the central axis of the cooling pipe is infinitely close to the surface of the mold, the structural strength and fatigue life of the mold are reduced.

In addition, the traditional casting, counter drilling, CNC numerical control milling and other modes are difficult to effectively manufacture the cooling pipeline die with the complex cross-sectional shape: the hot working mold for manufacturing the conformal cooling pipeline by adopting the traditional casting method needs a precise casting mold, the precise casting mold is processed by depending on more precise manufacturing and assembling technologies, and the precise pipeline internal mold is easy to deform due to residual stress generated by uneven cooling and high temperature in the casting process; the machining mode of the drill can only be used for machining the die insert with smaller length, and the machining of the internal threaded pipeline cannot be realized. Publication number CN102744328a also discloses a method for manufacturing a hot stamping die for a high-strength steel plate, which comprises the steps of firstly bending, prefabricating and connecting a cooling water channel pipeline, then separately processing a die groove for placing the water channel, and finally assembling and fixing to form a built-in conformal cooling water channel. The method is essentially a design and processing method of a combined cooling pipeline. Meanwhile, although the mould base with the complex pipeline can be manufactured accurately by using the CNC numerical control milling corresponding structure, the mould base is usually assembled after being manufactured separately, the problems of water seepage sealing, fatigue dislocation of connecting parts and the like exist, and the dimensional accuracy and the service life of the mould are further affected. For the cooling pipeline structure with a special cross section shape, the tool is required to be frequently replaced and the clamping position and angle of the workpiece are required to be changed during milling, so that the processing difficulty is increased, and the manufacturing cost is high.

In summary, it is necessary to provide a cooling water channel structure facilitating heat dissipation of a mold and a manufacturing method for processing the cooling water channel structure to solve the above-mentioned problems.

Disclosure of Invention

According to the technical problem, a conformal cooling pipe mold with internal threads and a manufacturing method thereof are provided. The invention is mainly designed by arranging a cooling pipeline in the die, wherein the shape of the cooling pipeline is the same as or similar to the surface shape of the die, the inner wall of the cooling pipeline is provided with a convex thread shape, and the diameter of the pipeline, the section shape and the size of the threads, the thread pitch value and the distance between the pipelines are optimized; and the die is prepared by a selective laser deposited metal 3D printing technology, so that the effects of strong structural adaptability, high heat dissipation efficiency, simplicity in manufacturing and the like are achieved.

The invention adopts the following technical means:

The conformal cooling pipeline mould with the internal thread is characterized in that a cooling water channel arranged in the mould consists of a plurality of cooling pipelines in a conformal trend or alternate winding form, and the axis of each cooling pipeline is a curve which has the same or similar curvature distribution with the surface of the mould;

The inner wall of the cooling pipeline is provided with raised internal threads so as to ensure that the medium in the inner pipeline is in a turbulent flow form and improve the heat exchange efficiency between the cooling medium and the inner wall (inner surface of the cooling pipeline) of the mould pipeline; the diameter of the cooling pipeline, the cross-sectional shape and size of the threads, the screw pitch value and the distance between the cooling pipelines are regularly changed according to a preset optimal design value.

The number of the conformal cooling pipelines in the die, the spacing between the parts of the conformal cooling pipelines and the normal distance parameter of the central axis of each part of the pipelines from the surface of the die are obtained through optimal design, so that the optimal heat exchange efficiency is obtained according to different die technological parameters; the optimization parameters are related to the actual processing parameters.

Further, according to different hardness requirements of processed products, the cross section shape of the internal thread of the cooling pipeline is divided into an involute tooth shape, a trapezoid shape, a semicircular shape, a semi-elliptic shape, a rectangular shape or a triangular shape, and the total diameter of the cooling pipeline and the geometric parameters of the cross section of the thread are obtained by optimizing design according to the screw pitch value of the thread so as to obtain optimal heat exchange efficiency and temperature field uniformity aiming at different mold process parameters.

Further, the screw pitch value of the internal thread of the cooling pipeline comprises an equivalent value, a variable value, a combination form of the equivalent value and the variable value, and the like, and the screw pitch parameter is also obtained by optimizing the design of the process and the temperature field so as to obtain the optimal heat exchange efficiency aiming at different types of mold process parameters.

Further, the variable form of the pitch value of the internal thread of the cooling pipe means that the thread value from the inlet to the outlet of the cooling pipe is distributed as a function along the axis.

Further, the thread values from the inlet to the outlet of the cooling pipe are distributed as a cubic or linear function along the axis.

Further, the cross-sectional diameters from the inlet to the outlet of the cooling duct are functionally or equi-valued along the axis, said functional distribution being a cubic or linear functional distribution.

Further, the material of the die is metal or resin.

The invention also discloses a manufacturing method of the conformal cooling pipeline mold with the internal threads, which is characterized in that a matrix part of the mold and a conformal cooling pipeline part are sequentially manufactured, a metal selective laser deposition (SLM) technology is adopted, the matrix part of the mold is prepared firstly based on casting and other modes, then a mold surface with the conformal cooling pipeline part is printed on the prepared matrix part in a mode of stacking layer by layer through 3D printing, and the 3D printed metal powder and the matrix part of the mold are made of the same material; or 3D printing of the whole die is carried out by adopting an SLM technology, or a core with a conformal cooling pipeline part is obtained by ceramic core printing and precoated sand printing, and then indirect 3D printing manufacturing is carried out.

The design structure and the manufacturing method related by the invention are applicable to all cooling molds related to fluid media (including liquid and gas), including but not limited to the design and the manufacture of hot stamping molds of automobile structural parts, the design and the manufacture of resin injection molds and the like.

Compared with the prior art, the cooling pipeline with the shape inside the die is designed to be of the threaded inner wall structure, so that the turbulence intensity of a cooling medium and the contact area between the cooling medium and the inner wall of the die can be improved, and particularly, the cooling medium flowing in laminar flow is divided into spiral flow moving along the small diameter of the threads and rotational flow and turbulent flow generated under the action of the resistance of the protruding parts of the threads, so that the heat exchange capacity of cooling water and the pipe wall is improved, and the cooling capacity of the hot working die is further improved. Different thread cross-sectional shapes and dimensional parameters have different disturbance effect capacities on cooling water, and in addition, different thread pitch values can also lead to different actual contact areas of cooling media and inner walls of the pipelines, and the influence can further lead to different cooling capacities of the dies. In addition, the distance between the conformal cooling pipes with the internal thread structures can influence the cooling capacity of the die, and in sum, the parameters can be optimized according to the index performance requirements of actual hot working on the die.

In addition, the conformal cooling pipe mold with the internal threads can be manufactured by selective laser melting metal 3D printing technology (SLM: SELECTIVE LASER MELTING) or can be obtained by special casting modes (such as ceramic core printing casting). Compared with the prior art, the SLM technology or the special casting mode of metal 3D printing can be used for manufacturing the high-precision conformal internal thread cooling pipeline die, so that the cooling efficiency of the die can reach the design cooling efficiency of the die easily, the related problems of sealing water leakage and the like are avoided, and the method has remarkable help for improving the quality of processed parts.

In summary, the cooling pipelines in the die are designed to be distributed along with the shape, the inner wall of the cooling pipeline along with the shape is designed to have a convex thread shape, and parameters of the thread, such as the section shape of the thread, the parameters of the thread, the pitch parameters, the number, the position and the distance of the cooling pipeline along with the shape are all optimized based on the requirement of hot working, so that the die achieves the optimal cooling effect; the mold with the internal thread conformal cooling pipeline is manufactured by a selective laser deposited metal 3D printing technology, and the related mold with the complex structure can be manufactured more conveniently and accurately. The invention has the advantages of strong structural adaptability, high heat dissipation efficiency, good uniformity, simple manufacture, good quality of part products, high die manufacturing precision, low cost, good manufacturing environment and the like, and can be widely applied to the related industries such as injection molding, hot stamping and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort to a person skilled in the art.

Fig. 1 is a schematic view showing the external structure of a conformal cooling pipe mold with internal threads according to embodiment 1 of the present invention.

Fig. 2 is a schematic diagram showing the distribution of the conformal cooling pipes inside the conformal cooling pipe mold with internal threads (before the internal thread structure design) in example 1 of the present invention.

Fig. 3 is a schematic diagram showing the distribution of the conformal cooling pipe inside the conformal cooling pipe mold with internal threads (after internal thread design) in example 1 of the present invention.

Fig. 4 is a schematic view of a high strength steel hot stamped structural member in example 1 of the present invention.

FIG. 5 shows the internal thread design in the conformal cooling pipe of the conformal cooling pipe mold with internal threads of example 1 of the present invention (examples 1-1).

Fig. 6 is a design drawing ii (examples 1-2) of the internal thread structure in the conformal cooling pipe of the conformal cooling pipe mold with the internal thread in example 1 of the present invention.

Fig. 7 is a design drawing iii (examples 1-2) of the internal thread structure in the conformal cooling pipe of the conformal cooling pipe mold with the internal thread in example 1 of the present invention.

Fig. 8 is a schematic distribution diagram of the conformal cooling pipe inside the injection mold with the internal thread (after the internal thread structure design) in embodiment 2 of the present invention.

FIG. 9 is a schematic view of a resin product in example 2 of the present invention.

Fig. 10 is a schematic cross-sectional view of a conformal cooling pipe i of an injection mold with an internal thread (after internal thread design) in example 2 of the present invention.

Fig. 11 is a schematic cross-sectional view of a conformal cooling pipe ii of an injection mold with an internal thread (after internal thread design) in embodiment 2 of the present invention.

Fig. 12 is a schematic diagram showing the distribution of the conformal cooling pipe injection mold with internal threads (after internal thread design) in example 3 of the present invention.

FIG. 13 is a schematic view of a resin product in example 3 of the present invention.

Fig. 14 is a schematic view of a manufacturing process of a hot stamping die (example 1) with an internally threaded conformal cooling pipe according to the present invention.

Fig. 15 is a schematic diagram showing the structural comparison of the conformal cooling pipe mold (a) with internal threads and the conformal cooling pipe mold (b) without internal threads and the non-conformal cooling pipe mold (c) without internal threads according to the present invention.

FIG. 16 is a comparative schematic diagram of temperature field distribution simulation performed by three different molds of FIG. 15.

In the figure: 1. a mold base portion; 2. a mold bulge; 3. a conformal water-cooling pipeline A; 4. a conformal water-cooling pipeline B; 5. a conformal water-cooling pipeline I; 6. a conformal water-cooling pipeline II; 7. shape-following water-cooling pipeline III; 8. a water-cooling pipeline I; 9. a water-cooling pipeline II; 10. a water-cooling pipeline III; 11. a die base flange surface; 12. concave fillets of the die base; 13. a male die fillet; 14. a male die surface; 15. high-strength boron steel hot stamping structural parts; 16. a convex front half; 17. a convex rear half; 18. bending the round-corner convexity; 19. a convex surface; 20. a flange fillet concave surface; 21. a part flange surface; 22. the rear half of the die; 23. a mold front half; 24. an axis II; 25. an axis III; 26. an axis I; 27. an inlet II; 28. an inlet III; 29. an inlet I; 30. an outlet II; 31. an outlet III; 32. an outlet I; 33. a thread section II; 34. a thread section III; 35. a thread section I; 36. a pitch value II; 37. a pitch value III; 38. a pitch value I; 39. thread section II'; 40. thread section III'; 41. pitch value ii'; 42. pitch value III'; 43. thread height II; 44. thread height III; 45. diameter II; 46. diameter III; 47. diameter II'; 48. diameter III'; 49. a die clamping table; 50. a mold body; 51. a mold cavity; 52. a conformal water-cooling pipeline I; 53. a conformal water-cooling pipeline II; 54. shape-following water-cooling pipeline III; 55. a resin product; 56. a central region; 57. a transition region; 58. an edge region; 59. an axis I'; 60. an axis II'; 61. a die clamping table I; 62. a die main body I; 63. a mold cavity I; 64. a conformal water-cooling pipeline; 65. a resin product I; 66. a base portion; 67. an additive printing portion; 68. a metal powder; 69. a laser emitter.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The shape-following cooling pipeline mold with internal threads is made of metal or resin, a cooling water channel arranged in the mold consists of a plurality of cooling pipelines in shape-following trend or alternate winding mode, and the axis of each cooling pipeline is a curve which has the same or similar curvature distribution as the surface of the mold;

the inner wall of the cooling pipeline is provided with a convex internal thread, and the diameter of the cooling pipeline, the cross-sectional shape and size of the thread, the screw pitch value and the distance between the cooling pipelines are regularly changed according to a preset optimal design value.

The cross section of the internal thread of the cooling pipeline is divided into involute tooth profile, trapezoid, semicircle, semi-ellipse, rectangle or triangle according to different hardness requirements of the processed product.

The pitch value of the internal thread of the cooling pipeline comprises an equivalent value, a variable value and a combination of the equivalent value and the variable value. The variable value form means that the thread value from the inlet to the outlet of the cooling pipeline is distributed along the axis in a function mode, and can be distributed in a cubic function mode or a linear function mode.

The cross-sectional diameters from the inlet to the outlet of the cooling pipe are distributed in a function or an equivalent distribution along the axis, wherein the function distribution is a linear function distribution or a nonlinear function distribution.

The invention also discloses a manufacturing method of the conformal cooling pipeline mold with the internal threads, which comprises the steps of sequentially manufacturing a matrix part and a mosaic conformal cooling pipeline part of the mold, and printing the mold surface with the conformal cooling pipeline part on the prepared matrix part layer by adopting a metal selective laser deposition technology (SLM); or 3D printing of the whole die is carried out by adopting an SLM technology, or a core with a conformal cooling pipeline part is obtained by ceramic core printing and precoated sand printing, and then indirect 3D printing manufacturing is carried out.

The method of designing the above-described mold and the method of manufacturing the same are described below in connection with specific embodiments.

Example 1

The die described in example 1 is a sheet metal hot stamping die (male die portion) which uses cooling water as a cooling medium. The method is particularly applied to a hot stamping forming process of a high-strength 22MnB5 boron steel plate to obtain a high-strength automobile boron steel structural member 15 with variable strength property distribution, and is described with reference to FIGS. 1-7.

As shown in fig. 1, the high-strength steel hot stamping die is composed of two parts, namely a hot stamping die base part 1 and a hot stamping die convex part 2, wherein the die base part 1 comprises a die base flange surface 11, a die base concave round corner 12, a conformal water-cooling pipeline A3 and a conformal water-cooling pipeline B4 under the base flange surface 11, a conformal water-cooling pipeline I5 under the die base concave round corner 12, and the die convex part 2 comprises a male die face 14, a male die round corner 13, a conformal water-cooling pipeline III7 under the male die face 14 and a conformal water-cooling pipeline II6 under the male die round corner 13.

The arrangement of the conformal water-cooling pipes inside the hot stamping die (before the design and addition of the internal thread structure) is as shown in fig. 2, the hot stamping die is of a central plane symmetrical structure (axisymmetrical structure), wherein the flange face 11 of the base part 1 of the hot stamping die is designed to be a plane, and the axes of the base concave round corners 12 are designed to be straight lines, so that the axes of the conformal water-cooling pipes A3, B4 and I5 are designed to be straight lines; the axes of the conformal water-cooling pipeline III7 and the conformal water-cooling pipeline II6 under the male die surface 14 and the male die fillet 13 of the male die convex part 2 are designed to be curves, and the shape and the curvature of the axes are the same as those of the male die surface 14.

In the actual production process, the upper convex surface 19 (shown in fig. 4) of the high-strength boron steel hot stamping structural member 15 has higher hardness requirement, the curved fillet convex surface 18 has highest hardness requirement, the flange fillet concave surface 20 of the high-strength boron steel hot stamping structural member 15 has lower hardness requirement, and the flange surface 21 of the part has lowest hardness requirement, so in the design of the conformal water cooling pipeline, the conformal water cooling pipeline I5, the conformal water cooling pipeline II6 and the conformal water cooling pipeline III7, internal thread structures are required to be added, as shown in fig. 3, the conformal water cooling pipeline after the internal thread structures are represented by the water cooling pipeline I8, the water cooling pipeline II 9 and the water cooling pipeline III 10, and the conformal water cooling pipeline A3 and the conformal water cooling pipeline B4 still adopt smooth inner wall structures. The specific cross-sectional geometry parameter design of the conformal water-cooled pipeline with internal threads based on the embodiment 1 is specifically developed from the embodiments 1-1 to 1-3.

Example 1-1

Embodiment 1-1 is a first design scheme of a water-cooling pipeline I8, a water-cooling pipeline II 9 and a water-cooling pipeline III 10 with internal threads inside the hot stamping die of embodiment 1, and is suitable for preparing hot stamping parts with uniform strength. As shown in fig. 5, the axis ii 24 of the water-cooling pipe ii 9 and the axis iii 25 of the water-cooling pipe iii 10 are identical to the shape and curvature of the male die face 14 of the male portion 2 of the hot stamping die, and the axis i 26 of the water-cooling pipe i 8 is still designed as a straight line. Because the high-strength boron steel hot stamping structural member 15 has higher hardness requirements on the upper convex surface 19 (shown in fig. 4) and the curved rounded convex surface 18 has highest hardness requirements, and the high-strength steel hot stamping structural member 15 has lower hardness requirements on the flange rounded concave surface 20, the thread section II 33 of the water cooling pipeline II 9 is triangular, the thread section III 34 of the water cooling pipeline III 10 is isosceles trapezoid, and the thread section I35 of the water cooling pipeline I8 is semicircular as shown in fig. 5; the screw pitch of the water cooling pipeline I8, the water cooling pipeline II 9 and the water cooling pipeline III 10 is designed to be constant, wherein the screw pitch II 36 of the water cooling pipeline II 9 is minimum, the screw pitch I38 of the water cooling pipeline I8 is maximum, the screw pitch III 37 of the water cooling pipeline III 10 is between the two, and the screw pitch and the geometric dimension of each water cooling pipeline are obtained through optimizing high-strength boron steel plate hot stamping conditions and parameters. Through the design, when the cooling water flow at the inlet of each water-cooling pipeline is equal, the conformal water-cooling pipeline II 9 has the maximum heat exchange efficiency, and the water-cooling pipeline I8 has the lowest heat exchange efficiency in all the threaded water channels; compared with the conformal water-cooling pipeline with the internal thread structure, the heat exchange efficiency of the conformal water-cooling pipeline I3 and the conformal water-cooling pipeline II 4 with the circular cross section of the smooth wall surface is obviously lower, and the design method can meet the hardness distribution requirement of the high-strength boron steel hot stamping structural member 15 in the embodiment 1-1.

Examples 1 to 2

Examples 1-2 are a second design of the water-cooled pipes I8, II 9 and III 10 with internal threads inside the conventional hot stamping die of example 1, and are suitable for preparing variable-strength hot stamped parts. Wherein the shape and curvature of the axis I26 of the water-cooled pipe I8, the axis II 24 of the water-cooled pipe II 9 and the axis III 25 of the water-cooled pipe III 10 are the same as those described in example 1-1. In this embodiment, the high strength boron steel hot stamped structural member 15 has a higher hardness requirement for the convex surface 19 (as shown in fig. 4) and the curved rounded convex surface 18 has the highest hardness requirement, the flange rounded concave surface 20 has a lower hardness requirement, and the part has a higher hardness distribution requirement for the convex rear half 17 than the convex front half 16, and the hot stamped structural member flange rounded concave surface 20 has the same hardness requirement as in embodiment 1-1. So the thread section II '39 of the water cooling pipeline II 9 uses a semicircle, the thread section III '40 of the water cooling pipeline III 10 uses a semicircle with a thread height III 44 slightly smaller than the thread height II 43 of the thread section II '39, and the water cooling pipeline II 9 and the water cooling pipeline III 10 adopt a variable pitch design, as shown in figure 6. From an inlet II 27 to an outlet II 30 of the water-cooling pipeline II 9, the pitch value II' 41 of the screw thread is distributed along the axis II 24 in a cubic function, the pitch value of the screw thread at the inlet II 27 is larger, and the pitch value at the outlet II 30 is smaller; from the inlet III 28 to the outlet III 31 of the water-cooled pipe III 10, the pitch value III' 42 of the thread is distributed as a linear function along the axis III 25, as shown in FIG. 6, and the pitch value of the thread at the inlet III 28 is larger and is also equal to the pitch value at the inlet II 27 of the water-cooled pipe II 9, and the pitch value at the outlet III 31 is smaller and is greater than the pitch value at the outlet II 30 of the water-cooled pipe II 9; the screw pitch values and the change rules (function parameter values along the axis) of the water-cooling pipeline II 9 and the water-cooling pipeline III 10 are obtained through optimizing the hot stamping conditions and parameters of the high-strength boron steel plate; the design of the geometrical parameters and the pitch I38 of the thread section I35 is the same as the design of the internal thread parameters of the water-cooled pipeline I8 in example 1-1, and the pitch I38 of the water-cooled pipeline I8 is still constant from the inlet I29 to the outlet I32 of the water-cooled pipeline I8. Through the design, when the cooling water flow rate of each water cooling pipeline inlet is equal, the heat exchange efficiency of the water cooling pipeline II 9 and the water cooling pipeline III 10 in the second half part 22 of the die can be higher than that of the first half part 23 of the die, the overall heat exchange efficiency of the water cooling pipeline II 9 is higher than that of the water cooling pipeline III 10, and the overall heat exchange efficiency of the water cooling pipeline I8 is equal to that of the water cooling pipeline I8 in the embodiment 1-1, and the design method can meet the hardness distribution requirement of the high-strength boron steel hot stamping structural part 15 in the embodiment 1-2.

Examples 1 to 3

Embodiments 1-3 are a third design scheme of the water-cooling pipeline I8, the water-cooling pipeline II 9 and the water-cooling pipeline III 10 with internal threads inside the hot stamping die of embodiment 1, and the method is suitable for preparing variable-strength hot stamping parts. Wherein the shape and curvature of the axis I26 of the water-cooled pipe I8, the axis II 24 of the water-cooled pipe II 9 and the axis III 25 of the water-cooled pipe III 10 are the same as those described in example 1-1. In this embodiment, the upper convex surface 19 (as shown in fig. 4) of the high-strength boron steel hot-stamped structural member 15 has higher hardness requirements, the curved rounded convex surface 18 has highest hardness requirements, the flange rounded concave surface 20 has lower hardness requirements, and the hardness distribution requirements of the convex rear half 17 of the high-strength boron steel hot-stamped structural member 15 are higher than those of the convex front half 16, and the flange rounded concave surface 20 of the hot-stamped structural member has higher hardness requirements and

The same is true for example 1-1, so in this example, water-cooled pipes II 9 and III 10 are not only still of variable pitch design, but also of variable cross-sectional diameter design, as shown in FIG. 7. The diameter of the cross section of the water-cooling pipeline II 9 is distributed along the axis II 24 in a cubic function, and the diameter II 45 of the water-cooling pipeline II 9 at the inlet II 27 is larger than the diameter II' 47 of the water-cooling pipeline II at the outlet II 30; the cross-sectional diameter of the water-cooled conduit III 10 is distributed as a linear function along the axis III 25, and the diameter III 46 at the inlet III 28 of the water-cooled conduit III 10 is greater than the diameter III '48 at the outlet III 31, the value of the diameter III '48 is greater than the value of the diameter II '47, and the value of the diameter III 46 is equal to the value of the diameter II 45; the thread cross-sectional shapes and the geometric dimensions, the thread pitch values and the change rules of the water-cooling pipelines II 9 and III 10 are the same as those of the water-cooling pipelines II 9 and III 10 in the embodiment 1-2; the section diameter values and the change rules (function parameter values along the axis) of the water-cooling pipeline II 9 and the water-cooling pipeline III 10 are obtained through optimizing the hot stamping conditions and parameters of the high-strength boron steel plate; the thread pitch I38 of the water-cooled pipe I8 is still constant, and the geometric parameters and the thread pitch I38 of the thread section I35 are designed in the same manner as those of the internal thread of the water-cooled pipe I8 in example 1-1. Through the design, when the cooling water flow rate of each water cooling pipeline inlet is equal, the heat exchange efficiency of the water cooling pipeline II 9 and the water cooling pipeline III 10 in the second half part 22 of the die can be more than that of the first half part 23 of the die, the overall heat exchange efficiency of the water cooling pipeline II 9 can also be more than that of the water cooling pipeline III 10, and the overall heat exchange efficiency of the water cooling pipeline I8 is equal to that of the water cooling pipeline I8 in the embodiment 1-1, so that the design method can meet the hardness distribution requirement of the high-strength boron steel hot stamping structural member 15 in the embodiment 1-3.

Example 2

The mold described in embodiment 2 is a resin injection mold (female mold part) which uses cooling water as a cooling medium. The present invention is particularly applicable to the processing of resin products to allow the resin to rapidly cool in the mold cavity to form the product, as described with reference to fig. 8-11.

As shown in fig. 8, the injection mold is composed of a mold clamping table 49, a mold main body 50, a mold cavity 51, a conformal water-cooling pipe i 52, a conformal water-cooling pipe ii 53, and a conformal water-cooling pipe iii 54 (other structures such as a feed inlet, a demolding mechanism, etc. are omitted). The resin product 55 produced by the injection mold is shown in fig. 9, wherein the resin product 55 is divided into three parts including a central region 56 having the greatest average thickness, a transition region 57 having the moderate average thickness, and an edge region 58 having the smallest average thickness.

In order to allow the resin product to be cooled rapidly and uniformly in the mold cavity, the conformal water-cooling pipe design in the mold main body 50 is as shown in fig. 8, 10 and 11, since the average thickness of the edge region 58 of the resin product 55 is thin, the heat dissipation speed of this region is relatively high, the conformal water-cooling pipe iii 54 under this region is designed as a smooth water-cooling pipe, and the axis of the conformal water-cooling pipe iii 54 is designed as a straight line, because the edge region 58 does not require a high heat exchange efficiency; because the average thickness of the transition area 57 of the resin product is larger, the requirement of the area on the heat exchange efficiency of the water-cooling pipeline is higher than that of the edge area 58, so the following water-cooling pipeline II 53 below the area is designed into a threaded pipe to increase the heat exchange efficiency of the water-cooling pipeline; meanwhile, as the average thickness of the central area 56 of the resin product 55 is the largest, the area has the highest requirement on the heat exchange efficiency of the water-cooling pipeline, the follow-up water-cooling pipeline I52 below the area is also designed into a threaded pipe, and the pitch value of the follow-up water-cooling pipeline I52 is smaller than that of the follow-up water-cooling pipeline II 53; the shape and curvature of the axes I '59 and II' 60 of the conformal water-cooling pipelines I52 and II 53 are the same as the shape and curvature of the die surface, the cross sections of the threads of the two water-cooling pipelines are designed into semi-circles with equal diameters, and the screw pitch value of each water-cooling pipeline is obtained through optimization of the cooling process parameters after resin injection molding. Through the above design, when the cooling water flow rate at the inlet of each water cooling pipe is equal, the cooling rate of almost all areas of the resin product 55 is rapid and the same, thereby ensuring the production efficiency and quality of the resin product.

Example 3

The mold of embodiment 3 is a resin injection mold (female mold part), and is specifically applied in the process of processing a resin product, so that the resin can be rapidly cooled in a mold cavity to form the product, and the cooling pipe is in a spiral winding form, which is described with reference to fig. 12 and 13.

As shown in fig. 12, the injection mold is composed of a mold clamping table i 61, a mold body i 62, a mold cavity i 63, and a conformal water cooling pipe 64 (other structures such as a feed port, a demolding mechanism, etc. are omitted). The resin product I65 produced by the injection mold is shown in FIG. 13. Due to the conical shape of the resin product I65 and the high heat dissipation efficiency required by the resin product, the axial shape of the conformal water cooling pipeline 64 in the injection mold main body I62 presents a spiral shape, the inner wall of the water cooling pipeline 64 is also designed with an internal thread structure, the section shape of the internal thread is designed into a triangle, and the height, the tooth root width, the pitch value and the change rule of the internal thread of the section triangle are all obtained through the optimization of the cooling process parameters after the resin injection molding. Compared with the design of a smooth conformal water cooling pipeline, the cooling efficiency of the resin product I65 can be improved, and the cooling rates of all parts of the product can be synchronized, so that the residual stress in the cooling process is reduced, and the production efficiency and the production quality of the resin product are ensured.

Example 1 Process for manufacturing Hot stamping die

As shown in fig. 14, the hot stamping die may be divided into two parts during manufacture, a base portion 66 of the die and an additive printed portion 67. The base portion 66 is simple in structure because of the absence of curved surfaces and internal thread structures, and thus can be mass-produced by conventional casting techniques to reduce manufacturing costs; the additive printing portion 67 cannot be obtained by casting or other traditional machining methods due to the curvature parameters of the die surface and the complex and precise internal thread structure of the conformal water-cooled pipeline, so that the additive printing portion can be obtained by an SLM metal 3D printing technology to ensure the manufacturing precision and the strength of the integral die structure. As shown in fig. 14, in the process of manufacturing the hot stamping die, a base portion 66 of the hot stamping die is first fixed, then a first layer of metal powder 68 is spread on the upper surface of the base portion, the kind of material of the metal powder is the same as that of the base portion 66 obtained by casting, then the metal powder layer 68 is selectively melted using a laser emitter 69 in an SLM device so that the first layer of metal powder 68 is clad with the surface of the die base portion to secure the strength of the structure, and then the metal powder spreading and laser melting are repeated until the additive printing portion 67 is manufactured. By such a manufacturing process, the manufacturing cost of the hot stamping die can be reduced, and the processing quality and manufacturing efficiency will be improved. For cooling molds with other structures, the manufacturing method can also adopt the SLM technology to carry out 3D printing manufacture of the whole mold or adopting special casting mode (such as ceramic core printing casting) to produce, so as to obtain the lowest manufacturing cost and the highest production quality and efficiency.

To describe in detail the cooling capacity of a conformal cooling pipe mold with internal threads, three different types of cooling molds were introduced for simulation analysis, namely a cooling mold with a conformal water cooling pipe with a threaded structure (as shown in fig. 15 a), a cooling mold without a conformal water cooling pipe with an internal thread structure (as shown in fig. 15 b), and a cooling mold without a non-conformal water cooling pipe with an internal thread structure (as shown in fig. 15 c). In simulation, the upper die surface of the die is added with the same inward heat flux density, and the simulation result is shown in fig. 16. Fig. 16a is a cooling effect of a mold with a follow-up type water-cooling pipe with an internal thread structure, fig. 16b is a cooling effect of a mold without a follow-up type water-cooling pipe with an internal thread structure, fig. 16c is a cooling effect of a non-follow-up type water-cooling pipe without an internal thread structure, and in a simulated cloud diagram, a unit of temperature is kelvin. It can be seen that the mold with the following cooling pipe having the internal thread structure has the lowest temperature, and the cooling effect is proved to be the best.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. The conformal cooling pipeline die with the internal threads is characterized in that the die is a metal plate hot stamping die; the hot stamping die comprises a hot stamping die base part and a hot stamping die convex part, wherein the die base part comprises a die base flange surface, a die base concave fillet, a conformal cold water pipeline A and a conformal water cooling pipeline B below the base flange surface, a conformal water cooling pipeline I below the die base concave fillet, and the die convex part comprises a male die surface, a male die fillet, a conformal water cooling pipeline III below the male die surface and a conformal water cooling pipeline II below the male die fillet;

The axes of the conformal water-cooling pipeline A, the conformal water-cooling pipeline B and the conformal water-cooling pipeline I are straight lines; the axes of the conformal water-cooling pipeline III and the conformal water-cooling pipeline II are curves, and the shape and the curvature of the axes are the same as those of the male die surface;

The conformal water-cooling pipeline I, the conformal water-cooling pipeline II and the conformal water-cooling pipeline III are added with internal thread structures, and the conformal water-cooling pipeline A and the conformal water-cooling pipeline B still adopt smooth inner wall structures;

The conformal water-cooling pipeline II and the conformal water-cooling pipeline III adopt variable pitch designs; the conformal water-cooling pipeline II and the conformal water-cooling pipeline III adopt a variable cross-section diameter design.

2. The conformal cooling pipe mold with internal threads according to claim 1, wherein the cross-sectional shape of the internal threads of the cooling pipe is classified as involute tooth profile, trapezoid, semicircle, semi-ellipse, rectangle or triangle according to hardness requirements of the processed product.

3. The conformal cooling pipe mold with internal threads according to claim 1, wherein the variable value form of the pitch value of the internal threads of the conformal water cooling pipe II and the conformal water cooling pipe III means that the thread value from the inlet to the outlet of the conformal water cooling pipe II and the conformal water cooling pipe III is distributed as a function along the axis.

4. A conformal cooling pipe mold with internal threads according to claim 3, wherein the thread values from the inlet to the outlet of the conformal water cooling pipe II and III are distributed as a cubic or linear function along the axis.

5. The internally threaded conformal cooling pipe mold of claim 1, wherein the cross-sectional diameters from the entrance to the exit of the conformal water cooling pipe II and III are distributed as a function along an axis, the function distribution being a cubic function distribution or a linear function distribution.

6. A method of manufacturing a conformal cooling pipe mold with internal threads as claimed in any one of claims 1 to 5, wherein a base portion of the mold and a mosaic conformal cooling pipe portion are sequentially manufactured, and a mold face having the conformal cooling pipe portion is deposited layer by layer on the prepared base portion by using a metal selective laser deposition technique SLM; or 3D printing of the whole die is carried out by adopting an SLM technology, or a core with a conformal cooling pipeline part is obtained by ceramic core printing and precoated sand printing, and then indirect 3D printing manufacturing is carried out.