A mold capable of opening and closing a magnetic field

Abstract

The application discloses a mold capable of opening and closing a magnetic field, which comprises a lower magnetic conducting block, a permanent magnet arranged on the lower magnetic conducting block, and a non-magnetic conducting cavity assembly, wherein the cavity assembly is provided with a cavity penetrating from top to bottom; the permanent magnet is arranged around the cavity assembly; the lower magnetic conducting block is provided with a first magnetic conducting part close to the lower part of the cavity; a magnetic conductor is arranged on the lower mold assembly and can move close to or away from the permanent magnet; the upper mold assembly and the lower mold assembly perform a mold closing action; the second magnetic conducting part is close to the upper part of the cavity; material enters the cavity to be formed; the magnetic conductor moves outward; the permanent magnet forms a magnetic circuit between the magnetic conducting parts to magnetically orient the material in the cavity; during mold opening, the magnetic conductor moves to the outside of the permanent magnet and the lower magnetic conducting block to shield the magnetic circuit between the magnetic conducting parts; the application has the advantages of better magnetic field orientation effect on the material and convenient product removal; and the application relates to the technical field of magnet forming molds.

Description

Technical Field

[0001] This invention relates to the field of magnet forming mold technology, and more specifically to a mold with an openable and closable magnetic field. Background Technology

[0002] In the manufacturing process of injection-molded magnets, after the material (a mixture of resin matrix and neodymium iron boron permanent magnet powder) is fed into the mold cavity, it is necessary to perform magnetic orientation on the material in the cavity. Magnetic field orientation is a key step, which directly affects the performance indicators of the magnet, such as remanence, coercivity and energy product.

[0003] In conventional molds, magnets are placed on both ends of the cavity to form a unidirectional magnetic field for magnetic orientation. However, traditional molds have many shortcomings, especially for high permanent magnet magnetic field orientation molds. When the orientation magnetic field is greater than 1T, after the injection molding is completed, the magnet is difficult to remove from the cavity due to the presence of the orientation magnetic field inside the cavity and the magnetization of the injected magnet. This greatly affects production efficiency.

[0004] Therefore, how to shut off the magnetic field inside the cavity after product injection molding, so as to quickly remove the injection-molded magnet, has become an urgent problem to be solved. Summary of the Invention

[0005] To address the shortcomings and defects of existing technologies, a mold with an openable and closable magnetic field is provided, which has a better effect on the magnetic field orientation of materials and facilitates product removal.

[0006] A mold with an openable and closable magnetic field, comprising:

[0007] Upper mold assembly, wherein the upper mold assembly is provided with a second magnetic conductive part;

[0008] Lower mold assembly, wherein the lower mold assembly is provided with a lower magnetic guide block;

[0009] The lower magnetically conductive block is equipped with a permanent magnet and a non-magnetic cavity assembly.

[0010] The cavity assembly is provided with a cavity that runs through the top and bottom;

[0011] The permanent magnet is arranged around the cavity assembly;

[0012] The lower magnetic block is provided with a first magnetic part that is close to the bottom of the cavity;

[0013] The magnetic conductor is mounted on the lower mold assembly and can move inward toward the permanent magnet or outward away from the permanent magnet.

[0014] The upper mold assembly and the lower mold assembly perform a mold closing action. The second magnetic conductive part approaches the top of the cavity, the material enters the cavity for molding, the magnetic conductive body moves outward, and the permanent magnet forms a magnetic circuit between the magnetic conductive parts to orient the material in the cavity with a magnetic field.

[0015] During the mold separation process, the magnetic conductor moves to the outside of the permanent magnet and the lower magnetic block, thereby shielding the magnetic circuit between the magnetic conductors.

[0016] With the above structure, the mold with an openable and closable magnetic field of the present invention has the following advantages compared with the prior art: When the mold is closed, the magnet forms a closed magnetic circuit in the cavity through the magnetic guide part, and performs magnetic field orientation on the material in the cavity. The magnetic field lines can be focused on the center of the cavity. In addition, the magnetic guide part close to the cavity can focus the magnetic field lines on the center of the cavity, making the magnetization performance of the material better. As a result, after processing, a magnet with better performance indicators such as remanence, coercivity and magnetic energy product is obtained.

[0017] Simulation results show that the upper and lower magnetic blocks and the magnetic ring form a closed magnetic circuit with a leakage rate of <3%; the magnetic field strength reaches 1.2T with a 10mm air gap and the non-uniformity is ≤5%, which is better than the 5.91% of the current semi-closed magnetization device.

[0018] During mold separation, the magnetic conductor moves to the outside of the permanent magnet and the lower magnetic block, thereby guiding the magnetic lines of force of the permanent magnet to form a loop through the magnetic conductor, thus shielding the magnetic circuit between the magnetic conductors, so as to facilitate the removal of the object and the normal operation of the device.

[0019] The movement of the magnetic conductor can dynamically adjust the magnetic circuit, making it easier to control the magnetic field during production, adapting to different production needs, and improving the adaptability and versatility of the mold.

[0020] As an improvement of the present invention, the upper end of the cavity assembly is provided with an upper magnetic guide block, the upper magnetic guide block is disposed in contact with the upper end surface of the permanent magnet, and a through hole is provided corresponding to the cavity for the second magnetic guide part to pass through and to fit into the outer periphery of the second magnetic guide part.

[0021] As an improvement of the present invention, the lower mold assembly includes a template, the template is provided with an accommodating space, and the cavity assembly and the magnet are disposed in the middle of the accommodating space;

[0022] The magnetic conductors are multiple and arranged around the magnets and cavity components within the accommodating space;

[0023] Multiple magnetic conductors move inward to form a ring structure, and the inner ring contacts the outer side of the magnet, the upper magnetic block, and the lower magnetic block.

[0024] The plurality of magnetic conductors move outward to break the ring structure, and the inner side disengages from the outer side of the magnet, the upper magnetic block, and the lower magnetic block.

[0025] As an improvement of the present invention, a movable seat that can move up and down is also provided below the template, and the movable seat is provided with an upwardly extending and outwardly inclined guide rod, and the magnetic conductor is provided with a guide hole through which the guide rod passes and whose inclination is consistent with the inclination of the guide rod.

[0026] As the movable seat moves the guide rod upward, the magnetic conductor moves inward and approaches the cavity assembly;

[0027] As the moving seat drives the guide rod downward, the magnetic conductor moves outward and away from the cavity assembly.

[0028] As an improvement of the present invention, the accommodating space is a rectangular structure, and the magnetic conductor is independently adapted to the interior angle of the accommodating space;

[0029] An inwardly protruding triangular prism is placed at the middle position of each side of the accommodating space, and the axis of symmetry of the triangular prism coincides with the center line of the side.

[0030] The sides of the triangles on two adjacent sides form a guiding space that points to the center of the accommodating space;

[0031] The magnetic conductor is provided with mating surfaces that contact the sides of the triangular bodies on the two adjacent sides.

[0032] As an improvement of the present invention, the cavity assembly is provided with receiving holes at the upper and lower ends of the cavity, and the receiving holes are connected to the cavity.

[0033] The receiving hole located above the cavity has a structure that is wider at the top and narrower at the bottom.

[0034] The receiving hole located below the cavity has a structure that is wider at the bottom and narrower at the top;

[0035] The second magnetic conductive part can fit into the receiving hole above the cavity, and the first magnetic conductive part fits into the receiving hole below the cavity.

[0036] As an improvement of the present invention, the upper mold assembly is provided with a feeding assembly, and the discharge end of the feeding assembly is connected to the cavity through an upper magnetic block.

[0037] As an improvement of the present invention, the upper end face of the lower magnetic block is fitted with the bottom end face of the permanent magnet, and after the mold is closed, the lower end face of the upper magnetic block is fitted with the upper end face of the permanent magnet.

[0038] As an improvement of the present invention, the lower mold assembly is further provided with an ejector rod, the upper end of which extends into the lower part of the cavity, so as to eject the material in the cavity after the upper mold and the lower mold are separated.

[0039] As an improvement of the present invention, the permanent magnet, the upper magnetic block and the lower magnetic block are all ring structures;

[0040] The inner side of the magnetic conductor has a groove, and the groove is adapted to the outer periphery of the permanent magnet, the upper magnetic block and the lower magnetic block. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of the present invention.

[0042] Figure 2 This is a structural schematic diagram of the present invention viewed diagonally.

[0043] Figure 3 This is the invention Figure 2 Enlarged schematic diagram of the structure at point A in the middle.

[0044] Figure 4 This is a schematic diagram of the half-section structure of the present invention.

[0045] Figure 5 This is a schematic diagram of the structure of the magnetic conductor of the present invention.

[0046] Figure 6 This is the invention Figure 5 Enlarged schematic diagram of the structure at point B.

[0047] Figure 7 This is a schematic diagram of the magnetic conductor and the guide rod of the present invention.

[0048] Figure 8 This is a schematic diagram of the position of the magnetic conductor after mold closing in this invention.

[0049] Figure 9 This is a schematic diagram of the position of the magnetic conductor after mold separation in this invention, and the material in the diagram is pushed out by the ejector rod.

[0050] Figure 10 This is a schematic diagram of the magnetic field simulation after the mold is closed according to the present invention.

[0051] Figure 11 This is a schematic diagram of the magnetic field simulation of the present invention during module splitting.

[0052] The figure shows: 1. Upper mold assembly; 1.1. Second magnetic guide part; 2. Lower mold assembly; 2.1. Template; 2.11. Accommodating space; 3. Lower magnetic guide block; 3.1. First magnetic guide part; 4. Permanent magnet; 5. Cavity assembly; 5.1. Cavity; 5.11. Accommodating hole; 6. Magnetic guide; 6.1. Guide hole; 6.2. Mating surface; 6.3. Groove; 7. Upper magnetic guide block; 8. Moving seat; 8.1. Guide rod; 9. Triangular body; 9.1. Side; 10. Feeding assembly; 11. Ejector rod. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0054] Please see Figure 1-11 As shown, a mold with an openable and closed magnetic field includes:

[0055] Upper mold assembly 1, wherein the upper mold assembly 1 is provided with an upper magnetic guide block 7;

[0056] Lower mold assembly 2, wherein the lower mold assembly 2 is provided with a lower magnetic guide block 3;

[0057] The lower magnetic block 3 is equipped with a permanent magnet 4 and a non-magnetic cavity assembly 5.

[0058] The cavity assembly 5 is provided with a cavity 5.1 that extends vertically.

[0059] The permanent magnet 4 is arranged around the cavity assembly 5;

[0060] The lower magnetic block 3 is provided with a first magnetic part 3.1 close to the bottom of the cavity 5.1, and the upper magnetic block 7 is provided with a second magnetic part 1.1;

[0061] The magnetic conductor 6 is disposed on the lower mold assembly 2, and can move inward toward the permanent magnet 4 or outward away from the permanent magnet 4.

[0062] Based on the working mechanism of the magnetic circuit and the static magnetic field boundary condition: According to Ampere's circuital law, the total magnetomotive force of a closed magnetic circuit satisfies:

[0063]

[0064] in and These correspond to the magnetic field strengths of the material and the cavity gap, respectively. Due to the relative permeability of the magnetically conductive material... Compared to the cavity region (air medium), ≈1) Three orders of magnitude higher, the magnetic flux will preferentially form a closed loop along the high permeability path.

[0065] Based on this principle, this invention incorporates a movable magnetic conductor 6 for adjustment. The distance is used to open and close the magnetic field.

[0066] The specific implementation is as follows:

[0067] The upper mold assembly 1 and the lower mold assembly 2 perform a mold closing action. The second magnetic conductive part 1.1 approaches the top of the cavity 5.1, and the material enters the cavity 5.1 for molding. The magnetic conductive body 6 moves outward, thus reducing... Thus The increase means that the permanent magnet 4 forms a magnetic circuit between the magnetic conductive parts, which magnetically orients the material in the cavity 5.1;

[0068] During the mold separation process, the magnetic conductor 6 moves to the outside of the permanent magnet 4 and the lower magnetic block 3, and the magnetic field forms a magnetic circuit through the magnetic conductor 6, thus increasing the magnetic field strength. Thus Reducing, or preventing, the magnetic field from entering the cavity, thereby shielding the magnetic field inside the cavity, achieves the effect of closing the magnetic field inside the cavity when the mold is opened, so as to facilitate the removal of the object and the normal operation of the device.

[0069] Simulation results show that the product has a magnetic leakage rate of <3%; the magnetic field strength reaches 1.2T with a 10mm air gap and the non-uniformity is ≤5%, which is better than the 5.91% of the current semi-enclosed magnetization device.

[0070] In addition, by setting a magnetic guide part close to the cavity 5.1, the magnetic field lines can be focused on the center of the cavity 5.1, resulting in a product with better performance indicators such as remanence, coercivity and magnetic energy product;

[0071] The movement of the magnetic conductor 6 can dynamically adjust the magnetic circuit, making it easier to control the magnetic field during the production process, adapting to different production needs, and improving the adaptability and versatility of the mold.

[0072] As an improvement of the present invention, the upper end of the cavity assembly 5 is provided with an upper magnetic guide block 7, which is disposed in close contact with the upper end surface of the permanent magnet 4, and is provided with a through hole corresponding to the cavity 5.1 for the second magnetic guide part 1.1 to pass through and to fit into the outer periphery of the second magnetic guide part 1.1.

[0073] Specifically, the magnetic conductive block and the magnetic conductive part are both made of 1J21 alloy with high magnetic permeability, which can optimize the magnetic circuit distribution and obtain a product with better performance.

[0074] As an improvement of the present invention, the lower mold assembly 2 includes a template 2.1, the template 2.1 is provided with a receiving space 2.11, and the cavity assembly 5 and the magnet are disposed in the middle position of the receiving space 2.11;

[0075] The number of magnetic conductors 6 is multiple, and they are arranged around the magnets and the cavity assembly 5 within the accommodating space 2.11;

[0076] Multiple magnetic conductors 6 move inward to form a ring structure, and the inner ring contacts the outer side of the magnet, the upper magnetic conductor 7, and the lower magnetic conductor 3.

[0077] The plurality of magnetic conductors 6 move outward to break the ring structure and disengage their inner sides from the outer sides of the magnet, the upper magnetic conductor 7, and the lower magnetic conductor 3.

[0078] The accommodating space 2.11 is located at the upper end of the template 2.1, and the cavity assembly 5 and the magnet are both annular structures.

[0079] When multiple magnetic conductors 6 work together to surround the magnet, the upper magnetic conductor 7, and the lower magnetic conductor 3, the magnetic conductors 6 are in close contact with each other, and the inner side of the magnetic conductor 6 is also in close contact with the magnet, the upper magnetic conductor 7, and the lower magnetic conductor 3, so as to form a uniform and consistent magnetic circuit, thereby providing a better shielding effect on the magnetic circuit inside the cavity 5.1.

[0080] When multiple magnetic conductors 6 work together to break away from the contact with the magnet, the upper magnetic conductor 7, and the outer side of the lower magnetic conductor 3, the magnetic circuit between the upper magnetic conductor 7, the lower magnetic conductor 3, and the magnetic conductor 6 is more effectively broken, so that the first magnetic conductor 3.1 and the second magnetic conductor 1.1 form a more uniform and powerful magnetic circuit between the cavity 5.1.

[0081] As an improvement of the present invention, a movable seat 8 that can move up and down is also provided below the template 2.1, and the movable seat 8 is provided with an upwardly extending and outwardly inclined guide rod 8.1, and the magnetic conductor 6 is provided with a guide hole 6.1 through which the guide rod 8.1 passes and whose inclination is consistent with the inclination of the guide rod 8.1;

[0082] When the movable seat 8 drives the guide rod 8.1 to move upward, the magnetic conductor 6 moves inward and approaches the cavity assembly 5;

[0083] When the movable seat 8 moves the guide rod 8.1 downward, the magnetic conductor 6 moves outward and away from the cavity assembly 5.

[0084] The guide rod 8.1 is designed to gradually slope towards the middle of the accommodating space 2.11 from top to bottom.

[0085] As the movable seat 8 moves upward, the lower end of the guide rod 8.1 gradually engages with the guide hole 6.1, thereby driving the magnetic conductor 6 to move inward.

[0086] As the movable seat 8 moves downward, the upper section of the guide rod 8.1 gradually engages with the guide hole 6.1, thereby driving the magnetic conductor 6 to move outward.

[0087] Through the cooperation of the movable seat 8 and the guide rod 8.1, precise control of the movement of the magnetic conductor 6 is achieved, which accurately controls the formation and shielding of the magnetic field, making the device highly reliable in operation.

[0088] As an improvement of the present invention, the accommodating space 2.11 has a rectangular structure, and the magnetic conductor 6 is independently adapted to the interior corners of the accommodating space 2.11;

[0089] In the middle of each side of the accommodating space 2.11, an inwardly protruding triangular body 9 is provided, wherein the axis of symmetry of the triangular body 9 coincides with the center line of the side.

[0090] The sides 9.1 of the triangular bodies 9 on two adjacent sides form a guide space pointing to the middle position of the accommodating space 2.11;

[0091] The magnetic conductor 6 is provided with a mating surface 6.2 that contacts the side surface 9.1 of the triangular body 9 on the two adjacent sides.

[0092] Specifically, the cross-section of the accommodating space 2.11 is a square structure, and the cross face of the triangular body 9 is an isosceles right triangle. After the axis of symmetry of the triangular body 9 coincides with the center line of the side of the accommodating space 2.11, a guide space is formed between the sides 9.1 of the triangular body 9, pointing towards the middle position of the accommodating space 2.11. The magnetic conductor 6 is provided with a mating surface 6.2 that contacts the side face 9.1 of the triangular body 9, which plays the role of guiding the movement of the magnetic conductor 6. In addition, with the guiding effect of the guide rod 8.1 and the guide hole 6.1, the magnetic conductor 6 can move stably inward or outward, further improving the control accuracy of the magnetic conductor 6.

[0093] As an improvement of the present invention, the cavity assembly 5 is provided with receiving holes 5.11 at the upper end and the lower end of the cavity 5.1, and the receiving holes 5.11 are connected to the cavity 5.1.

[0094] The receiving hole 5.11 located above cavity 5.1 has a structure that is wider at the top and narrower at the bottom.

[0095] The receiving hole 5.11 located below the cavity 5.1 has a structure that is wider at the bottom and narrower at the top;

[0096] The second magnetic conductive part 1.1 can fit into the receiving hole 5.11 above the cavity 5.1, and the first magnetic conductive part 3.1 fits into the receiving hole 5.11 below the cavity 5.1.

[0097] Specifically, the first magnetic conductive part 3.1 is also designed with a structure that is wider at the bottom and narrower at the top, and the second magnetic conductive part 1.1 is also designed with a structure that is wider at the top and narrower at the bottom. After the first magnetic conductive part 3.1 is engaged with the receiving hole 5.11 above the cavity 5.1, and after the second magnetic conductive part 1.1 is engaged with the receiving hole 5.11 below the cavity 5.1, it can better guide and concentrate the magnetic field lines, reduce the magnetic resistance in the magnetic circuit, and further improve the strength and uniformity of the magnetic field, thereby improving the effect of magnetic field orientation on the material in the cavity 5.1, and making the performance of the magnet after molding better.

[0098] As an improvement of the present invention, the upper mold assembly 1 is provided with a feeding assembly 10, and the discharge end of the feeding assembly 10 is connected to the cavity 5.1 through the upper magnetic block 7.

[0099] The feeding assembly 10 is used to feed the material (a mixture of resin matrix and neodymium iron boron permanent magnet powder) into the cavity 5.1 through the channel.

[0100] As an improvement of the present invention, the upper end face of the lower magnetic block 3 is fitted with the bottom end face of the permanent magnet 4, and after the mold is closed, the lower end face of the upper magnetic block 7 is fitted with the upper end face of the permanent magnet 4.

[0101] The close fit effectively reduces magnetic leakage in the magnetic circuit, better ensuring the integrity of the magnetic circuit. This allows the magnetic field generated by the permanent magnet 46 to be more effectively transmitted to the cavity 5.1 through the magnetic guide block, improving the utilization rate of the magnetic field, enhancing the magnetic field orientation effect on the material, and thus improving the performance of the magnet.

[0102] As an improvement of the present invention, the lower mold assembly 2 is further provided with an ejector rod 11, the upper end of which extends into the lower part of the cavity 5.1, so as to eject the material in the cavity 5.1 after the upper mold and the lower mold are separated.

[0103] After the magnetic conductor 6 shields the magnetic circuit inside the cavity 5.1, the upper mold assembly 1 and the lower mold assembly 2 perform the mold separation step. At this time, the magnetic circuit is formed between the lower magnetic conductor 3, the magnet, and the magnetic conductor 6. The ejector rod 11 moves upward, which can quickly and accurately eject the magnet inside the cavity 5.1, thus improving production efficiency.

[0104] As an improvement of the present invention, the permanent magnet 4, the upper magnetic block 7 and the lower magnetic block 3 are all ring structures;

[0105] The inner side of the magnetic conductor 6 has a groove 6.3, and the groove 6.3 is adapted to the outer periphery of the permanent magnet 4, the upper magnetic conductor 7 and the lower magnetic conductor 3.

[0106] Specifically, the groove 6.3 is in contact with the outer periphery of the permanent magnet 4, the upper magnetic block 7, and the lower magnetic block 3, and can fit tightly together to optimize the magnetic circuit distribution.

[0107] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A mold with an openable and closable magnetic field, characterized in that, include: Upper mold assembly (1), wherein the upper mold assembly (1) is provided with a second magnetic conductive part (1.1). The lower mold assembly (2) is provided with a lower magnetic block (3); The lower magnetic block (3) is provided with a permanent magnet (4) and a non-magnetic cavity assembly (5). The cavity assembly (5) is provided with a cavity (5.1) that runs vertically through the cavity. The permanent magnet (4) is arranged around the cavity assembly (5); The lower magnetic block (3) is provided with a first magnetic part (3.1) close to the bottom of the cavity (5.1). A magnetic conductor (6) is disposed on the lower mold assembly (2) and can move inward toward the permanent magnet (4) or outward away from the permanent magnet (4). The upper mold assembly (1) and the lower mold assembly (2) perform a mold closing action. The second magnetic conductive part (1.1) approaches the top of the cavity (5.1). The material enters the cavity (5.1) and is formed. The magnetic conductor (6) moves outward. The permanent magnet (4) forms a magnetic circuit between the magnetic conductive parts to orient the material in the cavity (5.1) with a magnetic field. During the molding process, the magnetic conductor (6) moves to the outside of the permanent magnet (4) and the lower magnetic block (3), thereby shielding the magnetic circuit between the magnetic conductors; The upper end of the cavity assembly (5) is provided with an upper magnetic guide block (7), which is attached to the upper end face of the permanent magnet (4) and has a through hole corresponding to the cavity (5.1) for the second magnetic guide part (1.1) to pass through and fit into the outer periphery of the second magnetic guide part (1.1); The lower mold assembly (2) includes a template (2.1), the template (2.1) is provided with a receiving space (2.11), and the cavity assembly (5) and the magnet are located in the middle of the receiving space (2.11); The number of magnetic conductors (6) is multiple, and they are arranged around the magnet and the cavity assembly (5) within the accommodating space (2.11); Multiple magnetic conductors (6) move inward to form a ring structure, and the inner ring contacts the outer side of the magnet, the upper magnetic conductor (7), and the lower magnetic conductor (3); The plurality of magnetic conductors (6) move outward to break the ring structure and disengage from the outer side of the magnet, the upper magnetic block (7), and the lower magnetic block (3).

2. The mold with an openable and closable magnetic field according to claim 1, characterized in that: Below the template (2.1) is a movable seat (8) that can move up and down, and the movable seat (8) is provided with an upwardly extending and outwardly inclined guide rod (8.1). The magnetic conductor (6) is provided with a guide hole (6.1) through which the guide rod (8.1) passes and whose inclination is consistent with that of the guide rod (8.1). When the movable seat (8) drives the guide rod (8.1) to move upward, the magnetic conductor (6) moves inward; When the movable seat (8) drives the guide rod (8.1) to move downward, the magnetic conductor (6) moves outward.

3. The mold with an openable and closable magnetic field according to claim 2, characterized in that: The accommodating space (2.11) has a rectangular structure, and the magnetic conductor (6) is independently adapted to the interior angle of the accommodating space (2.11); An inwardly protruding triangular body (9) is provided at the middle position of each side of the accommodating space (2.11), and the axis of symmetry of the triangular body (9) coincides with the center line of the side. The sides (9.1) of the triangular bodies (9) on two adjacent sides form a guide space pointing to the middle position of the accommodating space (2.11); The magnetic conductor (6) is provided with a mating surface (6.2) that contacts the side surface (9.1) of the triangular body (9) on the two adjacent sides.

4. The mold with an openable and closable magnetic field according to claim 1, characterized in that: The cavity assembly (5) is provided with receiving holes (5.11) at the upper and lower ends of the cavity (5.1), and the receiving holes (5.11) are connected to the cavity (5.1). The receiving hole (5.11) located above the cavity (5.1) has a structure that is wider at the top and narrower at the bottom. The receiving hole (5.11) located below the cavity (5.1) has a structure that is wider at the bottom and narrower at the top; The second magnetic conductive part (1.1) can fit into the receiving hole (5.11) above the cavity (5.1), and the first magnetic conductive part (3.1) fits into the receiving hole (5.11) below the cavity (5.1).

5. The mold with an openable and closable magnetic field according to claim 1, characterized in that: The upper mold assembly (1) is provided with a feeding assembly (10), and the discharge end of the feeding assembly (10) is connected to the cavity (5.1) through the upper magnetic block (7).

6. The mold with an openable and closable magnetic field according to claim 1, characterized in that: The lower mold assembly (2) is also provided with an ejector rod (11), the upper end of which extends into the lower part of the cavity (5.1) to eject the material in the cavity (5.1) after the upper mold and lower mold are separated.

7. The mold with an openable and closable magnetic field according to claim 1, characterized in that: The permanent magnet (4), the upper magnetic block (7) and the lower magnetic block (3) are all ring structures; The inner side of the magnetic conductor (6) has a groove (6.3), and the groove (6.3) is adapted to the outer periphery of the permanent magnet (4), the upper magnetic block (7) and the lower magnetic block (3).

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