Powder forming apparatus and method for a metal soft magnetic composite

Abstract

The application discloses a kind of powder forming equipment and method of metal soft magnetic composite material, belong to metal soft magnetic composite material forming technical field.The powder forming equipment of metal soft magnetic composite material disclosed in the application is provided with pressure driving unit, axial ultrasonic pressing rod assembly and radial ultrasonic mould assembly, realizes the process of powder material downward pressing, is subjected to axial vibration generated by axial ultrasonic pressing rod assembly and radial vibration generated by radial ultrasonic mould assembly, this axial radial bidirectional same-frequency ultrasonic vibration effectively solves the problem of intergranular friction force when unidirectional vibration compression, only relies on large load pressure forced compression to cause magnetic powder insulation layer to break, causes the problem of electromagnetic performance decline of forming product.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal soft magnetic composite material forming, and particularly relates to a powder forming device and method of metal soft magnetic composite material. BACKGROUND

[0002] Soft magnetic ferrite and metal soft magnetic composite material are the most important two types of soft magnetic materials constituting a soft magnetic powder core. The biggest advantage of soft magnetic ferrite is high resistivity, which enables it to maintain a low level of magnetic core loss at high frequency, but its saturation magnetization is generally lower than 0.5 T, which limits its application range and does not meet the development trend of miniaturization. The saturation magnetic induction of metal soft magnetic composite material is 0.75-1.6 T, but its resistivity is at least 4 orders of magnitude lower than that of soft magnetic ferrite, which makes the loss of metal soft magnetic composite material often higher in a high-frequency environment. Therefore, finding a method to control the high-frequency magnetic core loss has become a hot spot in the field of metal soft magnetic composite material research.

[0003] In the field of high-frequency applications, suppressing eddy current loss requires increasing resistivity, and for a magnetic powder core, the eddy current space can be suppressed by enhancing the insulation between powders. Therefore, improving and optimizing the insulation coating effect between magnetic powders is an important part of improving the performance of the magnetic powder core. The traditional preparation method of metal magnetic powder core includes cold pressing, hot (warm) pressing, and spark plasma sintering. The direct solution to improve the density is to increase the pressure and temperature. However, studies have found that simply increasing the pressure cannot improve the uniformity of the distribution of magnetic powders and binders in the mold and high packing density, etc., but can crush the magnetic powders and break the insulation layer, resulting in an increase in eddy current loss and even damage to the mold and press head. Local accumulation of binders can exacerbate pinning effects, causing poor soft magnetic performance and increased hysteresis loss. Based on the above industrial demand for high-frequency high-power density soft magnetic materials, the application potential of amorphous nanocrystalline materials, and the current status of pressing forming technology, it is urgent to innovate the pressing forming technology and process of amorphous nanocrystalline soft magnetic powder to achieve high-density pressing forming of magnetic powders.

[0004] Ultrasonic pressing technology has good directionality, high energy, and strong penetration ability, and can achieve tight forming of materials through its thermal and mechanical effects; ultrasonic vibration can effectively reduce the friction between particles, and the density of the powder forming body will increase due to the reduction of friction, and ultrasonic pressing technology can help the development of small-sized electronic devices and the improvement of manufacturing efficiency in the industry.

[0005] So far, ultrasonic pressing technology has not been applied to the preparation and production of magnetic powder cores, which is a research and technical blank. The ultrasonic vibration pressing equipment used in the current research also focuses on the needs of structural material preparation, and the adaptability to soft magnetic composite materials is poor. For example: the preparation of structural materials requires large pressure to deform plastically to increase density, while the plastic deformation of soft magnetic composite materials is not conducive to magnetic performance; soft magnetic materials should also weaken the thermal effect of ultrasonic vibration as much as possible, because high temperature may destroy the insulating layer on the surface of the powder, thereby deteriorating the performance. At the same time, the adjustable parameter range and precision integration of the equipment on the market are difficult to meet the needs of scientific research experiments, so it is urgent to develop new high-precision intelligent ultrasonic vibration pressing equipment. At present, the manufacturing field of soft magnetic powder core industry generally adopts axial pressure pressing forming process, and also adopts heating assisted forming process, and the related patents of ultrasonic assisted forming are only limited to one-way axial vibration mode. Such process is a one-way pressure action mode, which increases the density of single crystal soft magnetic powder, but inevitably crushes the magnetic powder and pierces the insulating layer, resulting in the increase of eddy current loss, and even damages the mold and the press head; Local binder aggregation can exacerbate pinning effect and cause soft magnetic performance to deteriorate and hysteresis loss to rise; For example, the Chinese patent application with publication number CN 106955998 A discloses a powder blank forming device and method. The scheme disclosed in the invention adopts a mold radial ultrasonic vibration method to compact the powder blank, which has the disadvantages of insufficient compaction and piercing the insulating layer, because the extrusion rod is axially compressed under the action of heavy load pressure. Such large load will limit the flowability of the powder particles, and one-way radial vibration does not effectively improve the flowability of the particles. If this process is applied to the pressing of metal soft magnetic composite magnetic cores, it will inevitably crush the magnetic powder and pierce the insulating layer, resulting in the increase of eddy current loss and the decline of electromagnetic performance of the finished product. For example, the Chinese patent application with publication number CN 117340243 A discloses a powder forming device, which can quickly transfer the ultrasonic wave energy emitted by the ultrasonic wave generator to the powder to achieve rapid forming by embedding the upper punch diamond coating of the upper punch with good acoustic wave conductor and the lower punch diamond coating with good acoustic wave conductor outside the mold cavity. The patent adopts an upper and lower punch moving towards each other method to compact the powder, and the vibration mode of the ultrasonic vibration and the upper and lower punch is not explicitly stated in the patent. The two vibration modes do not have associated actions, and each vibrates under the action of axial large load, which will inevitably limit the flowability of the powder particles, and also cause the process defects of crushing the magnetic powder, piercing the insulating layer and insufficient compaction. SUMMARY

[0006] The purpose of the present application is to provide a powder forming device and method for metal soft magnetic composite materials, which solves the technical problems of inevitable crushing of magnetic powder and piercing of insulating layer in the existing process.

[0007] In order to achieve the above object, the present application adopts the following technical solutions to achieve the above object:

[0008] The application discloses a powder forming device for a metal soft magnetic composite material, which comprises a pressure driving unit, a pressure rod, an upper pressing plate, an axial ultrasonic pressure rod assembly, a radial ultrasonic die assembly and a lower pressing plate.

[0009] Further, the axial ultrasonic pressure rod assembly comprises a press base, an axial transducer, an ultrasonic amplitude transformer, a pressure head and a positioning device.

[0010] Further, the positioning device comprises a spherical hinge flange base, a spherical hinge flange, a gland, a positioning flange, a positioning screw and a stud.

[0011] Further, the radial ultrasonic die assembly comprises a radial vibration pressing die, a mounting column, a stud, a radial transducer and a base.

[0012] Further, the radial vibration pressing die is connected with one end of the mounting column and is in contact with the base.

[0013] Further, the upper pressing plate and the lower pressing plate are connected and fixed through guide columns.

[0014] Further, the pressure driving unit and the pressure rod are connected with a die frame.

[0015] Further, the die frame and the upper pressing plate are connected and fixed through guide columns.

[0016] Further, the pressure driving unit is a servo cylinder.

[0017] The application further discloses a use method of the powder forming equipment of the metal soft magnetic composite material.

[0018] First, the powder material is added into the annular cavity formed in the radial ultrasonic mold assembly, and then the pressure driving unit is started to drive the upper pressing plate to drive the axial ultrasonic pressing rod assembly to start the pressing work, when the axial ultrasonic pressing rod assembly is 1-3 mm away from the upper end surface of the radial ultrasonic mold assembly, the axial ultrasonic pressing rod assembly and the radial ultrasonic mold assembly are started at the same time, and the axial ultrasonic pressing rod assembly continuously descends to press, so that in the pressing work, the powder material in the annular cavity is subjected to the axial vibration generated by the axial ultrasonic pressing rod assembly and the radial vibration generated by the radial ultrasonic mold assembly, under the action of the axial vibration and the radial vibration, when the pressure acting on the powder material reaches the rated pressure, the pressing is stopped, and the pressing product is obtained.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] The application discloses a powder forming equipment of a metal soft magnetic composite material, which realizes the axial vibration generated by the axial ultrasonic pressing rod assembly and the radial vibration generated by the radial ultrasonic mold assembly in the process of descending pressing of the powder material, and the axial and radial bidirectional ultrasonic vibration effectively solves the problem that the friction between particles in one-way vibration compression is forced to compress by large load pressure, the insulation layer of the magnetic powder is broken, and the electromagnetic performance of the formed product is reduced.

[0021] Further, under the action of the axial vibration generated by the axial ultrasonic pressing rod assembly and the radial vibration generated by the radial ultrasonic mold assembly, and the phase difference of 180 degrees in the two directions, when the maximum value of the axial negative displacement of the pressing head at the same time is ensured, the radial displacement of the mold cavity is the maximum value, when the axial displacement of the pressing head is the maximum positive value, the radial displacement of the mold cavity is the maximum negative value, the maximum hole of the mold cavity is expanded when the pressing head is under the action of the pressure, and the minimum hole of the mold cavity is contracted when the pressing head is retracted by vibration; the action mode can effectively increase the flowability of the powder particles, reduce the friction between the particles, effectively avoid the problem that the friction between the particles is too large in one-way vibration compression, the flowability of the powder material is affected, and the insulation layer of the magnetic powder is broken by forced compression by large load pressure, resulting in the reduction of the electromagnetic performance of the formed product.

[0022] Further, the ultrasonic pressing technology adopted has the characteristics of good directivity, large energy and strong penetration ability, and the material can be tightly formed by using the thermal effect and mechanical effect thereof; the ultrasonic vibration can effectively reduce the friction between the particles, and the powder forming body density will be improved due to the reduction of friction, and the ultrasonic pressing technology is helpful to the development of miniaturization of electronic devices and the improvement of manufacturing efficiency in the industry application field.

[0023] The application further discloses a use method of the powder forming equipment of the metal soft magnetic composite material. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Fig. 1 is a schematic diagram of the overall structure of the powder forming equipment of the metal soft magnetic composite material;

[0025] Figure 2 Fig. 2 is a perspective view of the powder forming equipment of the metal soft magnetic composite material;

[0026] Figure 3 Fig. 3 is a schematic diagram of the structure of the axial ultrasonic pressing rod assembly;

[0027] Figure 4 Fig. 4 is a top view of the radial ultrasonic mold assembly;

[0028] Figure 5 Fig. 5 is a schematic diagram of the structure of the radial ultrasonic mold assembly;

[0029] Figure 6 Fig. 6 is a mode correlation curve of axial vibration and radial vibration;

[0030] 1-servo cylinder; 2-mold frame; 3-pressing rod; 4-upper pressing plate; 5-axial ultrasonic pressing rod assembly; 5.1-pressing machine base; 5.2-axial transducer; 5.3-ball hinge flange base; 5.4-ball hinge flange; 5.5-pressing cover; 5.6-positioning flange; 5.7-positioning screw; 5.8-first stud; 5.9-ultrasonic amplitude rod; 5.10-pressing head; 6-guide column; 7-radial ultrasonic mold assembly; 7.1-radial vibration pressing mold; 7.2-powder material; 7.3-washer; 7.4-mounting column; 7.5-second stud; 7.6-radial transducer; 7.7-base; 8-lower pressing plate. DETAILED DESCRIPTION

[0031] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of embodiments of the present application, rather than all embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work should fall within the protection scope of the present application.

[0032] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in other than the order illustrated or described herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a list of steps or units need not be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to such processes, methods, products or devices.

[0033] The present application will be described in further detail below with reference to the drawings:

[0034] As shown in Figure 1 and Figure 2 The powder forming device of the disclosed metal soft magnetic composite material comprises a pressure driving unit, a pressure rod 3, an upper pressing plate 4, an axial ultrasonic pressure rod assembly 5, a radial ultrasonic mold assembly 7 and a lower pressing plate 8. After the pressure driving unit is connected with the mold frame 2, the mold frame 2 is connected with one end of the pressure rod 3 and the upper pressing plate 4. The other end of the upper pressing plate 4 is connected with one end of the axial ultrasonic pressure rod assembly 5. The radial ultrasonic mold assembly 7 is arranged on the surface of the lower pressing plate 8. One end of the axial ultrasonic pressure rod assembly 5 is opposite to the annular cavity formed in the radial ultrasonic mold assembly 7. The pressure driving unit is a servo cylinder 1.

[0035] As shown in Figure 3As shown in the figure, the axial ultrasonic pressure rod assembly 5 includes a press base 5.1, an axial transducer 5.2, an ultrasonic amplitude rod 5.9, a pressure head 5.10 and a positioning device; wherein the positioning device includes a ball hinge flange base 5.3, a ball hinge flange 5.4, a gland 5.5, a positioning flange 5.6, a positioning screw 5.7 and a first stud 5.8; one end of the press base 5.1 is fixed to the other end of the upper pressing plate 4; one end of the axial transducer 5.2 and one end of the ultrasonic amplitude rod 5.9 are connected; the other end of the ultrasonic amplitude rod 5.9 and one end of the pressure head 5.10 are connected; the other end of the pressure head 5.10 is opposite to the annular cavity formed in the radial ultrasonic mold assembly 7; one end of the ball hinge flange base 5.3 is connected to the other end of the press base 5.1; the ball hinge flange 5.4 is fixed on the ball hinge flange base 5.3; the axial transducer 5.2 is fixed on the ball hinge flange base 5.3; the other end of the ball hinge flange base 5.3 is connected through the positioning screw 5.7 and the positioning flange 5.6; the gland 5.5 is fixed on the ball hinge flange 5.4 through bolt coupling, so that the axial transducer 5.2 is fixedly coupled to the ball hinge flange 5.4.

[0036] As shown in the figure, Figure 4 and Figure 5 As shown in the figure, the radial ultrasonic mold assembly 7 includes a radial vibration pressure mold 7.1, a mounting column 7.4, a gasket 7.3, a second stud 7.5, a radial transducer 7.6 and a base 7.7, the base 7.7 is fixed on the surface of the lower pressing plate 8; the mounting column 7.4 is vertically arranged on the base 7.7; one end of the mounting column 7.4 is connected with the radial vibration pressure mold 7.1, and an annular cavity is formed with the center of the radial vibration pressure mold 7.1; both ends of the radial vibration pressure mold 7.1 are connected with the radial transducer 7.6 through the second stud 7.5; the radial vibration pressure mold 7.1 is connected with one end of the mounting column 7.4 and contacts with the base 7.7; the gasket 7.3 is arranged at the position where the radial vibration pressure mold 7.1 contacts with the base 7.7.

[0037] The powder forming equipment of the metal soft magnetic composite material has the following steps when working:

[0038] First, the powder material 7.2 is added into the annular cavity formed in the radial ultrasonic mold assembly 7. The servo cylinder 1 is activated to drive the upper pressure plate 4 to move the axial ultrasonic pressure rod assembly 5 downward to start the pressing process. When the pressure head 5.10 moves to a distance of 1~3mm from the upper end face of the radial vibration mold 7.1, the axial transducer 5.2 and the radial transducer 7.6 are activated at the same time. The axial vibration of the axial transducer 5.2 is converted into the axial high-frequency vibration of the ultrasonic amplitude rod 5.9 and the expansion and contraction vibration of the inner cavity of the radial vibration mold 7.1. The servo cylinder 1 continues to drive the upper pressure plate 4 to move the pressure head 5.10 downward. Under the action of bidirectional ultrasound, the powder of the metal soft magnetic composite material is compacted. When the rated pressure is reached, the servo cylinder 1 holds the pressure for a few seconds, the ultrasound stops working, and the servo cylinder 1 reverses the drive to withdraw the pressure head 5.10. The pressed finished product is taken out from the radial ultrasonic mold assembly 7, completing the ultrasonic-assisted pressing process of the magnetic ring.

[0039] The powder forming equipment for the soft magnetic metal composite material described in this invention innovatively employs bidirectional ultrasonic vibration of the same frequency in both the axial and radial directions, with a phase difference of 180 degrees between the two directions. Figure 6 As shown, when the axial negative displacement of the pressure head reaches its maximum value at the same moment, the radial displacement of the mold cavity is also at its maximum value. Conversely, when the axial displacement of the pressure head reaches its maximum positive value, the radial displacement of the mold cavity reaches its maximum negative value. This ensures that when the pressure head is under pressure, the mold cavity orifice is at its maximum expansion, and when the pressure head vibrates and retracts, the mold cavity orifice is at its minimum contraction. This mechanism effectively increases the flowability of powder particles and reduces the friction between particles. It also effectively avoids the friction between particles during unidirectional vibration compression, which can cause the magnetic powder insulation layer to crack due to forced compression under high load pressure, leading to a decrease in the electromagnetic properties of the molded product.

[0040] Secondly, by introducing ultrasonic vibration technology with bidirectional frequency but 180-degree phase difference in both axial and radial directions, the efficiency and quality of powder molding are significantly improved. The bidirectional vibration mode effectively promotes the omnidirectional flow of powder particles in three-dimensional space, not limited to a single direction, resulting in more uniform and dense powder filling, reducing porosity and defect formation, thereby improving product density and consistency. The 180-degree phase difference design ensures that the relative movement between the indenter and the mold cavity can alternately generate tensile and compressive effects. This dynamic change effectively reduces direct friction between particles and avoids stress concentration and insulation layer damage that may occur due to unidirectional vibration. It also reduces the risk of internal microcracks and electromagnetic property degradation caused by forced compression. Bidirectional vibration causes powder particles to rearrange within the mold, forming a more regular and compact stacked structure, which helps improve the dimensional accuracy and surface finish of the product and reduces the need for subsequent processing. By optimizing the arrangement of powder particles and reducing internal defects, bidirectional vibration molding technology can significantly improve the mechanical strength, electromagnetic properties, and corrosion resistance of soft magnetic composite materials, making them more suitable for high-performance and high-requirement applications.

[0041] Due to the enhanced powder flowability and optimized forming process, the defective rate and waste rate in the forming cycle are reduced, and the production efficiency and yield are improved. At the same time, the two-way vibration reduces the mold wear, prolongs the service life of the mold, and further reduces the production cost; this technology is not only suitable for metal soft magnetic materials, but also can be extended to other types of powder materials such as ceramics and hard alloys, showing wide material processing applicability and flexibility; by reducing material waste and energy consumption in the production process, and reducing the potential impact on the environment (such as reducing the emission of waste gas and wastewater), this technology not only realizes efficient production, but also meets the green development concept of modern manufacturing. The innovative design of the metal soft magnetic composite material powder forming equipment not only solves many problems in traditional single-direction vibration forming, but also significantly improves the quality and production efficiency of the product through various optimizations, providing strong support for the technological progress and industrial upgrading of the powder metallurgy industry.

[0042] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A powder forming apparatus for a metal soft magnetic composite material, characterized by, The utility model relates to a kind of axial radial bidirectional ultrasonic vibration moulding machines, including pressure driving unit, pressure rod (3), upper pressing plate (4), axial ultrasonic pressure rod assembly (5), radial ultrasonic mould assembly (7) and lower pressing plate (8);The pressure driving unit is connected by one end of pressure rod (3) and upper pressing plate (4);The other end of upper pressing plate (4) is connected with the one end of axial ultrasonic pressure rod assembly (5);Radial ultrasonic mould assembly (7) is arranged on the surface of lower pressing plate (8);The other end of axial ultrasonic pressure rod assembly (5) is opposite annular cavity formed in radial ultrasonic mould assembly (7); The axial ultrasonic pressure rod assembly (5) includes press seat (5.1), axial transducer (5.2), ultrasonic amplitude transformer (5.9), pressure head (5.10) and positioning device;One end of the press seat (5.1) is fixed to the other end of the upper pressing plate (4);The axial transducer (5.2) is fixed to the other end of the press seat (5.1) by the positioning device;One end of the axial transducer (5.2) is connected with one end of the ultrasonic amplitude transformer (5.9);The other end of the ultrasonic amplitude transformer (5.9) is connected with one end of the pressure head (5.10);The other end of the pressure head (5.10) is opposite the annular cavity formed in the radial ultrasonic mould assembly (7). The radial ultrasonic mould assembly (7) includes radial vibration pressure die (7.1), mounting column (7.4), second stud (7.5), radial transducer (7.6) and base (7.7);The base (7.7) is fixed on the surface of the lower pressing plate (8);The mounting column (7.4) is vertically arranged on the base (7.7);One end of the mounting column (7.4) is connected with the radial vibration pressure die (7.1), and forms an annular cavity with the center of the radial vibration pressure die (7.1);Both ends of the radial vibration pressure die (7.1) are connected with the radial transducer (7.6) through the second stud (7.5). The axial ultrasonic pressure rod assembly (5) generates axial vibration, and the radial ultrasonic mould assembly (7) generates radial vibration, so that axial radial bidirectional ultrasonic vibration is generated, and the phase difference of the two directions is 180 degrees.

2. A powder forming apparatus for a metal soft magnetic composite material according to claim 1, characterized in that, The positioning device includes ball hinge flange seat (5.3), ball hinge flange (5.4), gland (5.5), positioning flange (5.6), positioning screw (5.7) and first stud (5.8);One end of the ball hinge flange seat (5.3) is connected with the other end of the press seat (5.1);The ball hinge flange (5.4) is fixed on the ball hinge flange seat (5.3);The axial transducer (5.2) is fixed on the ball hinge flange seat (5.3);The other end of the ball hinge flange seat (5.3) is connected through the positioning screw (5.7) and the positioning flange (5.6);The gland (5.5) is fixed on the ball hinge flange (5.4) by bolt connection, so that the axial transducer (5.2) is fixedly connected to the ball hinge flange (5.4).

3. The powder forming apparatus of a metal soft magnetic composite material according to claim 1, wherein The radial vibration pressure die (7.1) is connected with one end of the mounting column (7.4), and contacts with the base (7.7);The position where the radial vibration pressure die (7.1) contacts with the base (7.7) is provided with a gasket (7.3).

4. The powder forming apparatus of a metal soft magnetic composite material according to claim 1, wherein The upper pressing plate (4) and the lower pressing plate (8) are connected and fixed through guide columns (6).

5. The powder forming apparatus of a metal soft magnetic composite material according to claim 1, wherein The pressure driving unit is connected with the pressing rod (3) through a mold frame (2).

6. A powder forming apparatus for a metal soft magnetic composite material according to claim 5, wherein The mold frame (2) and the upper pressing plate (4) are connected and fixed through guide columns (6).

7. The powder forming apparatus of a metal soft magnetic composite material according to claim 1, wherein The pressure driving unit is a servo cylinder (1).

8. The method of using a powder forming apparatus for a metal soft magnetic composite material according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: First, the powder material (7.2) is added into the annular cavity formed in the radial ultrasonic mold assembly (7), and then the pressure driving unit is started to drive the upper pressing plate (4) to drive the axial ultrasonic pressing rod assembly (5) to start the pressing work, when the axial ultrasonic pressing rod assembly (5) is 1-3 mm away from the upper end surface of the radial ultrasonic mold assembly (7), the axial ultrasonic pressing rod assembly (5) and the radial ultrasonic mold assembly (7) are started at the same time, and the axial ultrasonic pressing rod assembly (5) continuously descends to press, so that in the pressing work, the powder material (7.2) in the annular cavity is subjected to the axial vibration generated by the axial ultrasonic pressing rod assembly (5) and the radial vibration generated by the radial ultrasonic mold assembly (7) at the same time, under the action of the axial vibration and the radial vibration, when the pressure acting on the powder material (7.2) reaches the rated pressure, the pressing is stopped, and a pressing product is obtained.

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