CN109605733B

CN109605733B - Magnetic material 3D printing apparatus

Info

Publication number: CN109605733B
Application number: CN201910069223.6A
Authority: CN
Inventors: 李志祥; 张海青; 程昱川; 张建飞; 许高杰; 郭建军
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2019-01-24
Filing date: 2019-01-24
Publication date: 2021-05-04
Anticipated expiration: 2039-01-24
Also published as: CN109605733A

Abstract

The invention relates to a magnetic material 3D printing device. Specifically, on the basis of the traditional fused deposition modeling equipment (FDM), the equipment adopts a screw extrusion structure to replace a traditional gear wire feeding mechanism, and a magnetizing device is arranged at the lower end of the screw extrusion structure, so that the molding efficiency and the magnetic performance of a magnetic material can be greatly improved.

Description

Magnetic material 3D printing apparatus

Technical Field

The invention relates to the field of material processing, in particular to a magnetic material 3D printing device.

Background

Additive manufacturing technology (also called "3D printing") is a method of directly manufacturing a three-dimensional physical entity in a layer-by-layer build-up manner based on a computer three-dimensional CAD model. The additive manufacturing technology can rapidly and precisely manufacture parts with any complex shapes and structures on one piece of equipment, thereby realizing 'free manufacturing'. Compared with the traditional processing technology, the additive manufacturing can reduce the processing cost by more than 20-40%, and shorten the product research and development period by about 80%.

In the last 20 years, additive manufacturing technology has been rapidly developed, forming a variety of forming techniques and equipment. The technologies are oriented to the high-end manufacturing fields of aerospace, weaponry, automobiles, molds, biomedical science and the like, the three-dimensional complex structure is directly manufactured, and the manufacturing problem that the traditional manufacturing process is difficult or even impossible to process is solved. The 3D printing technology (additive manufacturing) can be processed into an ideal shape based entirely on the results of electromagnetic theory calculations. Through reasonable magnetic circuit design, can solve the outer magnetic leakage of stator and tip magnetic leakage. Meanwhile, the magnetic powder/plastic composite material is generally used as a raw material for 3D printing, so that the conductivity of the material is lower than that of a silicon steel sheet, and the influence of a direct-current bias magnetic field on iron loss can be further reduced. And the 3D printing technology does not need die sinking, has short processing period and wide processing size range, and can timely and rapidly adjust the design scheme according to theoretical design and practical results. The preparation process is free from the thought limit of designers, and a powerful technical guarantee is provided for developing a novel permanent magnet motor with a complex structure, high electric energy conversion efficiency and high rare earth material utilization rate.

At present, the 3D printing technology is mainly used for structural part forming. Development and optimization of 3D printing processes of functional parts such as magnetic parts and the like are still in the research and development stage. Due to the fact that no special magnetic material for 3d printing exists, the difference of magnetic properties of magnets prepared by different research institutions is large. Moreover, special magnetic material printing equipment is lacked, the mode of firstly printing and then magnetizing is adopted at present, the advantages of 3d printing of complex magnetic circuit devices are not fully exerted, and a certain gap is left from practical application.

Therefore, the research and development of special materials, equipment, processes and applications for 3D printing of the magnetic materials are of great significance.

Disclosure of Invention

The invention aims to provide a magnetic material 3D printing device and a method for printing a magnetic part by using the device.

In a first aspect of the present invention, there is provided a magnetic material 3D printing apparatus, the apparatus comprising: an extrusion mechanism, a forming platform, a displacement mechanism and a control unit, wherein,

the extrusion mechanism is used for conveying raw materials to the forming platform, the displacement mechanism is used for moving the extrusion mechanism to a required printing position, and the control unit is used for controlling the equipment.

In another preferred example, the extruding mechanism includes a first extruding mechanism for extruding a first raw material, and the first extruding mechanism includes a feeding portion, an extruding portion, and a first heating portion which is located at an end of the first extruding mechanism and is used for heat-treating the first raw material to be extruded.

In another preferred example, the first raw material comprises a powder material and a plastic.

In another preferred embodiment, the powder material includes (but is not limited to) magnetic powder, such as neodymium iron boron, samarium cobalt, alnico, ferrite, or combinations thereof.

In another preferred embodiment, the plastic includes (but is not limited to): nylon 12, nylon 6, nylon 66, ABS, PC, POM, PEEK, PEI, PI, PETG, PLA, PPS, and the like.

In another preferred embodiment, the mass content of the powder material in the first raw material is 5 to 95wt%, preferably 30 to 90 wt%, more preferably 40 to 85 wt%, and most preferably 50 to 80 wt%.

In another preferred embodiment, the bending strength of the wire processed from the first raw material is 20MPa or less, preferably 15MPa or less, more preferably 10MPa or less.

In another preferred embodiment, the diameter of the wire is 1.5-5 mm, preferably 1.75. + -. 0.02mm or 3. + -. 0.05 mm.

In another preferred embodiment, the supply portion is funnel-shaped for transferring the first raw material into the sleeve.

In another preferred embodiment, the extruded portion comprises: extrude motor, shaft coupling, extrude screw rod, sleeve and shaping part, extrude motor, shaft coupling, extrude the screw rod and set up according to the preface, the sleeve is located extrude the screw rod periphery and with the terminal intercommunication of feed part, the shaping part is located telescopic end just is used for will extruding the screw rod first raw and other materials shaping after conveying the shaping platform.

In another preferred example, the coupling is used for connecting the extrusion electrode and the extrusion screw so as to transmit the power of the extrusion electrode to the extrusion screw.

In another preferred example, the end of the supply portion communicates with an opening at the middle upper end of the sleeve.

In another preferred example, the first extruding means is for extruding a first raw material forming the body of the magnetic material.

In another preferred embodiment, the extruding mechanism further includes a second extruding mechanism, the second extruding mechanism is used for extruding a second raw material, and the second extruding mechanism includes a material guiding pipe, a wire feeding gear, a second heating portion and an extruding head, the second heating portion is located at the tail end of the material guiding pipe and is used for heating the second raw material which is about to leave the material guiding pipe.

In another preferred example, the wire feeding gear is used for conveying the second raw material in the guide pipe to the forming platform.

In another preferred example, the extrusion head is located at the end of the guide tube for extruding the second raw material to be discharged from the guide tube.

In another preferred embodiment, the second raw material is a wire.

In another preferred embodiment, the diameter of the wire is 1.5-5 mm, preferably 1.6-1.8 mm or 2.6-3.2mm, more preferably 1.75 + -0.02 mm or 3 + -0.05 mm.

In another preferred example, the second extruding means is for extruding a second raw material forming a supporting material of the magnetic material.

In another preferred example, the forming platform comprises a printing platform, a heating device and a leveling device, the heating device is located below the printing platform, and the leveling device is used for adjusting the table top of the printing platform to be parallel to the movement axis of the displacement mechanism.

In another preferred example, the apparatus further includes a magnetizing device located at an outer periphery of the first heating portion and configured to magnetize the heated first raw material.

In another preferred example, the magnetizing device comprises an electromagnet exciting part, a soft magnet magnetic conducting part, a rotating mechanism and a shielding cover.

In another preferred example, the electromagnet excitation part is located above the soft magnetic conducting part.

In another preferred example, the rotating mechanism is used for rotating the magnetizing device.

In another preferred example, the structure formed by the electromagnet excitation part, the soft magnet magnetic conduction part and the rotating mechanism is surrounded by the shielding cover except the lower part of the structure.

In another preferred embodiment, non-magnetic material is used to connect the following parts: extrusion mechanism, pay-off structure, moving part.

In another preferred example, the displacement mechanism includes an up-down, left-right movement control section and a front-rear movement control section.

In another preferred example, the up-down, left-right movement control section and the front-rear movement control section each include a movement axis.

In another preferred embodiment, the control unit comprises a controller, a display and an input terminal.

In a second aspect of the invention, a 3D printing method of a magnetic material is provided, printing being performed using the apparatus of the first aspect of the invention.

In another preferred embodiment, a first raw material is delivered to the forming station by a first extrusion mechanism, and the first raw material is heated prior to exiting the first extrusion mechanism.

In another preferred example, the first raw material is further subjected to an in-situ magnetization treatment during the heating treatment.

In another preferred embodiment, a second raw material is delivered to the forming station by a second extrusion mechanism, and the second raw material is heated before exiting the second extrusion structure.

In another preferred embodiment, the forming table is heat-treated by the heating device before (and while) the first and second raw materials are conveyed to the forming table.

The technical scheme of the invention is provided aiming at the problems that the powder addition content is high, the plastic binder phase is less, the brittleness is high after the wire material is prepared, and the wire material cannot be printed by adopting the gear wire feeding (because the wire is too brittle, the wire material is clamped and broken in the feeding process of the rule wheel, the wire material cannot be smoothly pushed forward, and the printing cannot be finished).

The existing magnetic material is printed and then magnetized, magnetic domains are not pre-oriented in the printing process, so that the magnetism is low, the early-stage foundation of a house is not firm, the later-stage magnetization (equivalent to re-reinforcement) is realized, and the overall performance is not too high.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

Drawings

Fig. 1 is a schematic structural diagram of a magnetic material 3D printing apparatus according to the present invention.

Fig. 2 is a schematic structural diagram of an extrusion mechanism in the magnetic material 3D printing device according to the present invention.

Fig. 3 is a schematic structural diagram of a forming platform in the magnetic material 3D printing apparatus of the present invention.

Fig. 4 is a schematic structural diagram of a magnetizing device in the magnetic material 3D printing apparatus according to the present invention.

Fig. 5 is a schematic structural diagram of a control unit in the magnetic material 3D printing apparatus according to the present invention.

Detailed Description

Through long-term and intensive research, the inventor introduces a screw extrusion structure to replace a traditional gear wire feeding mechanism on the basis of the traditional Fused Deposition Modeling (FDM), directly converts raw materials into products, omits a processing step of converting the raw materials into printable wires, and improves the modeling efficiency. The equipment is particularly suitable for the fields of high powder addition content, less plastic binder phase, high brittleness after being made into wires and incapability of printing by adopting a gear to feed wires. Meanwhile, a magnetizing device which can rotate independently is added at the lower end of a forming device of the equipment, and the magnetic material is pre-oriented according to the requirement, so that the magnetic property of a printed part is improved, and the processing of a complex magnetic circuit device is realized; in addition, in order to prevent the introduction of a magnetic field from causing adverse effects on a motor, a displacement control component and the like, a shielding cover is added outside the magnetizing device to ensure that the magnetic field is intensively acted on a printing piece; and the magnetic field influence areas are connected by adopting non-magnetic materials. On this basis, the inventors have completed the present invention.

The term "magnetization" as used herein refers to a phenomenon that a magnetic material exhibits a certain magnetic property due to the fact that the magnetic moments in the material tend to be aligned when aligned under the action of a magnetic field.

"fused deposition modeling" in the present invention is the melt deposition at a fixed rate and following a predetermined trajectory for each layer of the part by extruding a fuse of filamentary material, such as thermoplastic, wax or metal, from a heated nozzle. And when one layer is finished, the workbench descends one layer thickness to carry out superposition deposition on a new layer, and the steps are repeated to finally realize the processing of the 3-dimensional part.

The electromagnet in the invention is a device which generates a magnetic field when being electrified. The core is wound with an electrically conductive winding adapted to its power, and the coil, which is energized with electric current, is magnetic like a magnet.

The permanent magnet is a material with wide magnetic hysteresis loop, high coercive force and high remanence, and can keep constant magnetism after being magnetized, and is also called permanent magnet material and hard magnet material.

Compared with the prior art, the invention has the following main advantages:

(a) the magnetic material 3D printing equipment adopts a double-nozzle structure, can respectively form the removable supporting material and the main magnetic material on one piece of equipment, is suitable for preparing a magnet with a complex shape, and has good surface smoothness of the prepared magnet;

(b) the equipment adopts a screw extrusion structure to replace the traditional gear wire feeding mechanism, directly converts raw materials into products, omits the processing step of converting the raw materials into printable wires, and improves the molding efficiency. The equipment is particularly suitable for the fields of high powder addition content, less plastic binder phase, high brittleness after being made into wires and incapability of printing by adopting a gear to feed wires.

(c) The magnetic material 3D printing equipment adopts an in-situ magnetization mode, the magnetic field pre-orientation efficiency is high, and the orientation direction is flexible and controllable;

(d) the magnetic material printing process converts the magnetic field orientation into printing path control, and can realize perfect compatibility with the existing 3d printing control software;

(e) the magnetic material printing process has the advantages of no need of mold opening, short processing period, wide processing size range, capability of designing a magnetic field as required and the like.

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers. Unless otherwise indicated, percentages and parts are by weight.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred embodiments and materials described herein are intended to be exemplary only.

Examples

Fig. 1 is a schematic structural diagram of a magnetic material 3D printing apparatus according to the present invention. The whole equipment comprises: the device comprises five parts, namely an extrusion mechanism 1, a forming platform 2, a displacement mechanism 3, a magnetizing device 4 and a control unit 5. Wherein the extrusion mechanism 1 comprises a feeding part 1-1, a heating part 1-2, an extrusion motor 1-3, a coupling 1-4, an extrusion screw 1-5, a sleeve 1-6, a forming part 1-7, a material guide pipe 1-8, a wire feeding gear 1-9, a heater 1-10 and an extrusion head 1-11; the forming platform 2 comprises a printing platform 2-1, a heating device 2-2 and a leveling device 2-3; the displacement mechanism 3 comprises an up-down left-right movement control 3-1 and a front-back movement control 3-2; the magnetizing device 4 comprises an electromagnet exciting part 4-1, a soft magnet magnetic conducting part 4-2, a rotating mechanism 4-3 and a shielding case 4-4; the control unit 5 comprises a controller 5-1, a display 5-2 and an input terminal 5-3.

Specifically, the extrusion mechanism is responsible for stacking raw materials to a specific place as required, the forming platform is a processing working space, the displacement mechanism is responsible for moving the printing head to a specific position, the magnetizing device is used for pre-orienting a magnetic domain of a printed magnet as required, and the control unit is responsible for operation control and external interaction of equipment.

Fig. 2 is a schematic structural diagram of an extrusion mechanism in the magnetic material 3D printing device according to the present invention. Wherein, the feeding part 1-1 is funnel-shaped, the material is added from the top and leaks from the slit at the lower right side; the heating part 1-2 is a block-shaped heater which can be a copper heating ring for a screw rod, a heating spring or a metal ring with a heating rod, and aims to realize local heating; the extrusion motor 1-3 is responsible for rotating and generating power; the shaft coupling 1-4 transmits the rotation of the motor to the extrusion screw; the extrusion screws 1-5 generate spiral motion to drive the materials to move forwards; the sleeves 1-6 are a barrel-shaped shell outside the screw to limit the material from moving towards two sides and ensure the material to move forwards or backwards.

FIG. 3 is a schematic structural diagram of a forming platform in the magnetic material 3D printing apparatus of the present invention, which is an operation space for printing and forming, wherein the printing platform 2-1 is a work table; the heating device 2-2 heats the table top, and the printed objects are prevented from warping or deforming due to too large change of cold and heat; and the leveling device 2-3 is used for adjusting the table top to be parallel to the movement axis of the displacement mechanism, so that the printing precision is ensured.

Fig. 4 is a schematic structural diagram of a magnetizing device in the magnetic material 3D printing apparatus according to the present invention. The electromagnet excitation part 4-1 generates a magnetic field with a certain size according to requirements; the soft magnetic part 4-2 turns the magnetic field generated by the electromagnet and guides the magnetic field to a specific position; the rotating mechanism 4-3 rotates the magnetizing device to form 360-degree dead-angle-free operation; and the shielding cover 4-4 is used for shielding the internal magnetic field and preventing the magnetic field from diffusing outwards to cause electromagnetic interference on the motor and the controller. The equipment can carry out magnetic pre-orientation on the raw materials with high efficiency, and the orientation direction is flexible and controllable.

Fig. 5 is a schematic structural diagram of a control unit in the magnetic material 3D printing apparatus according to the present invention. Wherein, the controller 5-1 is a central controller and is responsible for controlling internal motion, magnetic field and the like; the display 5-2 displays the implementation state of the printer, so that man-machine interaction is facilitated; the input terminal 5-3 is a human-computer interaction terminal, which is convenient for a person to control the equipment.

The device according to the invention is particularly suitable for 3D printing of raw materials having the following characteristics: high powder addition content, less plastic binder phase, high brittleness after being made into wire materials, and incapability of printing by adopting gear wire feeding. Particularly, when the magnetic powder content is high, it is important to achieve uniform feeding and fixed molding of raw materials for the performance of the magnetic material obtained by printing. The magnetic powder can be understood as a disk of loose sand, how to smoothly convey the sand, and after the conveying is finished, the sand can be directly changed into concrete with a specific required configuration instead of a disk of loose sand. The above-mentioned apparatus of the present invention can effectively solve the above-mentioned printing problem of the above-mentioned special raw material.

In addition, in a local narrow space, ensuring that the magnetic field is oriented according to a designed path and causing no interference to surrounding motors and the like is very important for realizing pre-orientation of the magnetic material and smooth printing of the magnetic material.

Compared with the existing magnetic material 3D printing equipment, the equipment disclosed by the invention has the advantages of wide range of applicable materials, high forming efficiency, capability of magnetizing raw materials in situ before forming and capability of obtaining a magnetic material 3D printing piece with excellent magnetic performance.

For example, for a raw material composed of nylon 12 and neodymium iron boron with 0.5 wt% of Pr added, wherein the weight percentage of the nylon 12 is 30%, and the weight of the magnetic powder is 70%, the content of the magnetic powder is too high by adopting the traditional FDM printing equipment, the wire is too brittle, and the bending strength is less than 5Mpa, so that the printing cannot be performed. But the equipment is adopted, the wire does not need to be prepared, and the wire can be directly formed. In the printing process, if an external magnetic field of 0.8T is not added, magnetization is carried out after printing, the magnetic induction coercive force is below 0.4T, if the external magnetic field which is increased by 0.8T along the printing direction is adopted, the magnetic induction coercive force can reach 0.8T to the maximum extent, and the space is further improved through magnetic powder component optimization.

All documents referred to herein are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes and modifications of the present invention can be made by those skilled in the art after reading the above teachings of the present invention, and these equivalents also fall within the scope of the present invention as defined by the appended claims.

Claims

1. A 3D printing apparatus for magnetic material, the apparatus comprising: an extrusion mechanism, a forming platform, a displacement mechanism, a magnetizing device and a control unit, wherein,

the extrusion mechanism is used for conveying raw materials to the forming platform, the displacement mechanism is used for moving the extrusion mechanism to a required printing position, and the control unit is used for realizing control over the equipment;

the extrusion mechanism comprises a first extrusion mechanism, the first extrusion mechanism is used for extruding a first raw material, the first extrusion mechanism comprises a feeding part, an extrusion part and a first heating part, and the first heating part is positioned at the tail end of the first extrusion mechanism and is used for heating the first raw material to be extruded;

the extruded portion comprises: the device comprises an extrusion motor, a coupler, an extrusion screw, a sleeve and a forming part, wherein the extrusion motor, the coupler and the extrusion screw are sequentially arranged, the sleeve is positioned on the periphery of the extrusion screw and is communicated with the tail end of the feeding part, and the forming part is positioned at the tail end of the sleeve and is used for forming a first raw material extruded by the extrusion screw and then conveying the first raw material to the forming platform;

the first raw material comprises a powder material and a plastic;

the powder material is magnetic powder;

in the first raw material, the mass content of the powder material is 50-95 wt%;

the extruding mechanism further comprises a second extruding mechanism, the second extruding mechanism is used for extruding a second raw material, the second extruding mechanism comprises a material guide pipe, a wire feeding gear, a second heating part and an extruding head, and the second heating part is located at the tail end of the material guide pipe and is used for heating the second raw material which is about to leave the material guide pipe;

the second raw material is a wire material;

the magnetizing device is located on the periphery of the first heating portion and is used for carrying out magnetization treatment on the heated first raw material.

2. The apparatus of claim 1, wherein the extrusion mechanism is vertically disposed.

3. The apparatus according to claim 1, wherein the second extruding mechanism is adapted to extrude a second raw material forming a support material for the magnetic material.

4. The apparatus of claim 1, wherein the forming table comprises a printing table, a heating device located below the printing table, and a leveling device for adjusting a table of the printing table to be parallel to an axis of movement of the displacement mechanism.

5. The apparatus of claim 1, wherein the first extrusion mechanism is to extrude a first stock material that forms the body of magnetic material.

6. The apparatus according to claim 1, wherein the displacement mechanism comprises an up-down, left-right movement control section and a front-back movement control section.

7. A method of 3D printing of magnetic material, characterized in that printing is performed using the apparatus of claim 1.

8. The method of claim 7, wherein a first raw material is delivered to the forming station by a first extrusion mechanism, and the first raw material is heat treated prior to exiting the first extrusion mechanism.

9. The method of claim 8, wherein the first raw material is further subjected to an in-situ magnetization process during the heating process.

10. The method of claim 7, wherein a second raw material is delivered to the forming station by a second extrusion mechanism, the second raw material being heat treated prior to exiting the second extrusion structure.