JP3972769B2 - Structure manufacturing method, magnetic body manufacturing method, and structure manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a structure using a cross-sectionally laminated three-dimensional manufacturing method, and particularly to a method and an apparatus suitable for manufacturing a magnet.
[0002]
[Prior art]
As an example of a structure, there is a conventional method for producing a magnet (magnetic material). A composite particle obtained by kneading a magnetic material powder and a resin as a binder is formed into a predetermined shape of gold. When the magnetic material has magnetic anisotropy in a mold, a magnetic field is applied in order to align the magnetic direction of the composite particles, and then a precursor is obtained by pressure molding and firing, and the precursor There is a method for producing a magnet by magnetizing the magnet.
Alternatively, there is a method of forming the precursor by injection molding a mixture of a magnetic material and a binder made of a thermoplastic resin.
[0003]
However, in the conventional method, since it is molded using a mold, it is difficult to manufacture magnets having complicated irregularities. Generally, magnetic materials are hard and brittle materials. The problem that it is difficult to form irregularities, and when using a magnetic material with magnetic anisotropy, even if a magnetic field is applied before molding, the magnetic direction at the composite particle level is only aligned and the composite particle is formed. There is a problem that sufficient magnetic field directivity cannot be obtained because the magnetic direction cannot be aligned at the powder particle level of the magnetic material.
[0004]
[Problems to be solved by the invention]
The subject of this invention is providing the manufacturing method and manufacturing apparatus of a structure which can manufacture the structure of complicated shapes, such as a magnetic body, for example, without using a metal mold | die.
Another object of the present invention is to provide a method for producing a magnetic material that can produce a magnetic material having excellent magnetic field directivity using a magnetic material having magnetic anisotropy.
[0005]
[Means for Solving the Problems]
The method for producing a magnetic body of the present invention includes a powder layer forming step of forming a powder layer made of a powdered magnetic material having magnetic anisotropy, an excitation step of applying a magnetic field to the powder layer, By repeating the binder discharge step for discharging droplets containing the binder to the powder layer, the powder layer forming step, the excitation step, and the binder discharge step a plurality of times, the powder layers are sequentially laminated, A precursor forming step for forming a precursor, and applying a magnetic field in a direction different from that of the other excitation steps in at least one of the excitation steps performed a plurality of times.
[0006]
According to this method, a magnetic field having a direction different from that of the other excitation processes is applied at least once in the excitation process performed a plurality of times, so that the three-dimensional magnetization axis direction differs depending on the laminated powder layers. The magnetic body can be manufactured without using a mold.
[0007]
Another method for producing a magnetic material of the present invention includes a powder layer forming step for forming a powder layer made of a powdered magnetic material having magnetic anisotropy, and an excitation step for applying a magnetic field to the powder layer. And by repeating the binder discharge process for discharging droplets containing a binder to the powder layer, the powder layer forming process, the excitation process, and the binder discharge process multiple times, the powder layers are sequentially laminated to form a magnetic layer. A precursor forming step for forming a precursor of the body, and at least one of the excitation steps performed a plurality of times, magnetic fields having different orientations in different portions of the region where the binder of one powder layer is discharged It is characterized by applying.
[0008]
According to this method, in at least one of the excitation steps performed a plurality of times, different directions of magnetic fields are applied to different portions of the region where the binder of one powder layer is discharged. Therefore, a three-dimensional magnetic body having a plurality of regions with different easy axis directions can be manufactured without using a mold.
[0009]
In the magnetic body manufacturing methods of these inventions, the powder layer may be formed so as to have a thickness different from that of the other powder layer forming steps in at least one of the powder layer forming steps performed a plurality of times. . According to this method, the thickness of the powder layer is thin in a portion where the three-dimensional shape of the magnetic material is complicated, and the thickness is thicker than that in the former in a simple portion, that is, for each powder layer to be laminated. By adjusting the thickness, a complicated three-dimensional magnetic body can be manufactured without using a mold. In this case, it is desirable that the thickness of the powder layer is at least equal to or larger than the particle size of the magnetic material and does not cause uneven contact between the binder and the powder.
[0010]
Further, in at least one of the powder layer forming steps performed a plurality of times, the powder layer may be formed using a magnetic material different from other powder layer forming steps. According to this method, a three-dimensional magnetic body made of different magnetic materials can be manufactured without using a mold.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings. Here, as an example of a structure having a predetermined shape to be manufactured, a manufacturing apparatus and a method for manufacturing a magnet that is one of magnetic bodies will be described.
(Manufacturing equipment)
FIG. 1 shows an embodiment of a magnet manufacturing apparatus according to the present invention.
Reference numeral 1 in the figure denotes a base 1 having a recess (layer formation region) 1a capable of accommodating powder. The surface 1c of the base 1 is a horizontal plane, and the directions parallel to and perpendicular to each other are defined as the X direction and the Y direction, and the thickness direction of the base 1, that is, the depth direction of the recess 1a is defined as the Z direction. The bottom surface 1b of the recess 1a is a horizontal plane, and the bottom surface 1b is configured to be able to advance and retract in the vertical direction (Z direction). Reference numeral 7 in the figure is drive means for advancing and retracting the bottom surface 1b of the recess 1a, and is composed of, for example, a ball screw, a linear motor, an air cylinder, or the like.
A powder storage tank 2 for storing powder is provided above the base 1 so that a predetermined amount of powder is supplied from the powder storage tank 2 into the recess 1 a of the base 1. It is configured. Further, a blade 3 is provided which can move in the X direction and the Y direction while being in contact with the surface of the base 1. By moving this blade 3, the surface of the powder layer supplied into the recess 1 a is changed. It is configured so that it can be leveled with the surface of the base 1. In this embodiment, the powder layer forming means includes a powder storage tank 2 and a blade 3.
[0014]
Further, a head (ejection means) 4 having a plurality of nozzles for ejecting droplets is provided above the base 1 so as to be movable in the X direction and the Y direction. The nozzles of the head 4 are provided on the lower surface of the head 4 and are configured such that droplets containing a binder are discharged from these nozzles to the powder layer in the recess 1 a of the base 1. Yes. As the configuration of the head 4, a configuration of a droplet discharge head in a known ink jet apparatus can be used.
Reference numerals 8a and 8b in the figure are drive means for moving the head 4, and are composed of, for example, a ball screw, a linear motor, an air cylinder or the like.
Further, the heater 5 can evaporate and dry the solvent contained in the droplets applied to the powder layer by heating the powder layer in the recess 1a of the base 1 as necessary. It is configured.
[0015]
A pair of magnetic field generators (exciting means) 6 and 6 are provided outside the base 1 so as to face each other with the recess 1a of the base 1 interposed therebetween. The magnetic field generators 6 and 6 can generate a magnetic field in the direction from one to the other, and for example, an electromagnetic coil or the like is used.
Advancement and retreat of the bottom surface 1b of the recess 1, supply of powder from the powder storage tank 2 into the recess 1a of the base 1, movement of the blade 3, movement of the head 4 and discharge of droplets, on / off of the heater 5, The magnetic field generators 6 and 6 are turned on / off by a control device (not shown).
[0016]
(Production method)
Next, a method for manufacturing a magnet according to the present invention will be described.
The magnetic material used in the present invention may be any material that can be magnetized by applying a magnetic field to form a magnet, and various known magnetic materials can be used as the constituent material of the magnet. Preferably, a compound of an iron group transition metal and a rare earth metal is preferable. Specifically, an Nd—Fe—B (neodymium-iron-boron) compound, an Sm—Co (samarium-cobalt) compound, an Sm—Fe—N ( Samarium-iron-nitrogen) compounds and the like are preferable.
The magnetic material is used in the form of powder. The particle size of the magnetic material powder is not particularly limited. However, it is preferable that the handling and fluidity in the powder layer forming process, which will be described later, are good, and that the powder density when it is spread in a thin layer is higher. The average particle size is preferably about several μm to several tens of μm.
The magnetic material may have magnetic anisotropy or may exhibit magnetic isotropy. In this specification, a magnetic material having magnetic anisotropy has the property of being magnetized only in the direction of the easy axis of magnetization, and can make a stronger magnet by aligning the direction (orientation) with a magnetic field during molding. Examples of magnetic materials that can be used include Sm-Co (samarium-cobalt) compounds. The magnetic material having magnetic isotropy is a magnetic material having the property of being magnetized equally from any direction, such as an Nd—Fe—B (neodymium-iron-boron) compound.
[0017]
The binder used in the present invention can be combined with a powdered magnetic material to form a solid having a hardness that can withstand use as a magnet, and as a droplet from a discharge means of a magnet manufacturing apparatus. There is no particular limitation as long as it can be prepared in a liquid form that can be discharged. For example, a thermosetting resin such as an epoxy resin, a thermoplastic resin such as a nylon resin, an elastomer such as a synthetic rubber, a heat resistant resin such as a polyimide resin, an ultraviolet curable resin, or the like can be used.
The binder is used by mixing with a solvent as necessary. The solvent is not particularly limited, and a solvent having good compatibility with the binder to be used can be selected from known solvents. Specific examples of the solvent include alcohols such as ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, and cellosolve, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, cyclohexane, hexane, heptane, octane, mineral spirits, Examples thereof include hydrocarbon compounds such as benzene, toluene, and xylene.
[0018]
Next, an embodiment of a method for manufacturing a magnet using the manufacturing apparatus having the configuration shown in FIG. 1 will be described.
2A and 2B are diagrams for explaining the powder layer forming step and the excitation step. FIG. 2A is a perspective view, and FIG. 2B is a diagram schematically showing a cross section taken along line BB in FIG. . In the figure, reference numeral 11 denotes a powder layer, and 11a denotes a magnetic material powder (hereinafter also referred to as magnetic powder). In the present embodiment, a case where a material having magnetic anisotropy is used as a magnetic material will be described as an example.
[0019]
(Powder layer forming process)
The shape of each divided body obtained when the three-dimensional shape of the magnet to be obtained is divided into a plurality of layers by cutting planes parallel to each other is previously converted into data by a computer. In the present embodiment, the cut surface is set as an XY plane, and a direction perpendicular to the cut surface is set as a Z direction. Moreover, the thickness (distance between cut surfaces) of each divided body in the Z direction is defined as d. The thickness d of the divided body corresponds to the thickness of one layer of the powder layer 11, and the smaller the thickness d of the divided body, the more complicated the shape of the magnet can be handled, but the manufacturing time increases. The thickness d of the divided body may be equal to or larger than the particle diameter of the magnetic powder 11a. However, if the thickness d of the powder layer 11 is too large, the binder and the powder are discharged when the binder is discharged to the powder layer 11. Since the contact with the body is non-uniform and there is a possibility that the bonding of the powder becomes insufficient, it is preferable to set in a range in which such inconvenience does not occur.
It should be noted that the thicknesses d of the plurality of divided bodies constituting one magnet may not be equal to each other. For example, in a portion where the three-dimensional shape of the magnet is simple, it is more divided than a portion where the three-dimensional shape is complicated. Can be set large.
[0020]
First, the powder layer 11 for forming the lowermost divided body in the Z direction among the plurality of divided bodies constituting the magnet is formed.
That is, as shown in FIG. 2, the magnetic powder 11 a stored in the powder storage tank 2 is supplied into the recess 1 a of the base 1, and then the surface of the magnetic powder 11 a is replaced with the surface of the base 1 by the blade 3. The powder layer 11 is formed by leveling with 1c. At this time, the bottom surface 1b of the recess 1a is positioned so that the depth from the surface of the base 1 to the bottom surface 1b is the thickness d of the divided body. As a result, a powder layer 11 having a thickness d equal to the depth is formed in the recess 1a.
[0021]
(Excitation process)
Next, in this embodiment, since the magnetic powder 11a has magnetic anisotropy, a magnetic field is applied to the powder layer 11 to align the direction of the magnetic powder 11a.
Specifically, a pair of magnetic field generators 6 and 6 provided on both sides of the recess 1a of the base 1 are operated to generate an external magnetic field in a direction from one of the magnetic field generators 6 and 6 to the other. . Thereby, the direction of the individual magnetic powders 11a constituting the powder layer 11 is changed so that the easy magnetization axis direction is parallel to the direction of the external magnetic field. In the figure, the arrows indicate the direction of the external magnetic field and the easy axis of magnetization in the magnetic powder 11a.
If the strength of the external magnetic field applied to the powder layer 11 in this excitation process is too weak, sufficient energy cannot be generated to direct the powder, and if it is too strong, the powder itself is scattered in the magnetic field direction. It is desirable to adjust appropriately according to the particle size of the magnetic powder and the arrangement distance of the magnetic field generator.
[0022]
(Binder discharge process)
Next, as shown in FIG. 3, droplets containing a binder are ejected from the nozzles of the head 4 to the powder layer 11. The discharge of the droplet containing the binder can be performed by a well-known inkjet method.
At this time, the movement of the head 4 and the discharge of the liquid droplets are controlled based on the shape data of the divided body 21 which is the lowermost side of the magnet. A droplet containing a binder is ejected onto a region corresponding to the divided body 21 (shown by hatching in the figure).
The physical properties such as the viscosity and surface tension of the droplets containing the binder can wet the surface of the magnetic powder 11a at the position where the droplet is discharged to the powder layer 11, and are lower than the discharged powder layer 11. It is preferable to adjust so that it does not flow easily.
Further, if necessary, after droplets are ejected onto the powder layer 11, the powder layer 11 is heated by the heater 5 to evaporate the solvent contained in the droplets ejected onto the powder layer 11. The droplets may be dried.
Thereby, in the area | region where the droplet containing the binder was discharged among the powder layers 11, the magnetic powder 11a and the binder are couple | bonded and integrated, and the division body 21 on the lowest side of a magnet is formed.
[0023]
(Precursor formation step)
FIG. 4 is a schematic cross-sectional view for explaining the precursor forming step. This figure shows a state in which the divided bodies 21, 22, 23, 24 from the bottom to the fourth layer are formed.
After the lowermost divided body 21 of the magnet is formed as described above, the second-layer divided body 22 is formed from the bottom. That is, after the lowermost divided body 21 is formed, the bottom surface 1b of the concave portion of the base 1 is moved downward by a distance d in the Z direction, so that the lowermost division is made from the surface 1c of the base 1. The depth to the surface of the powder layer 11 including the body 21 is defined as d. Then, in the same manner as in the powder layer forming step, the magnetic powder 11a is supplied into the recess 1a, and then the surface is leveled by the blade 3 to form the second powder layer 22, and this second layer powder. An external magnetic field is applied to the body layer 22 in the same manner as the excitation step to align the direction of the magnetic powder. Thereafter, in the same manner as in the binder discharging step, droplets are discharged to a predetermined region of the second powder layer 22 based on the shape data of the second layer 22 from the bottom, By removing the solvent and drying as necessary, a second-layer divided body 22 is formed on the lowermost divided body 21 from the bottom.
Subsequently, similarly, the bottom surface 1b of the concave portion of the base 1 is moved, the third powder layer 13 is formed, the excitation process and the binder discharge process are performed on the third powder layer, By repeating a series of steps of forming a third-layer divided body 23 from the bottom on the second-layer divided body 22, the divided bodies are stacked and formed in order from the lower layer.
Then, after the formation up to the uppermost divided body is completed, the binder in each divided body is cured to integrate all the divided bodies, and the entire layer is divided from the magnetic powder 11 a in the recess 1 a of the base 1. The solid with which the body is integrated, that is, the precursor of the magnet is taken out.
[0024]
(Magnetization process)
Furthermore, a magnet is obtained by applying a magnetic field to the obtained precursor and magnetizing the precursor.
[0025]
According to the present embodiment, it is possible to easily manufacture a magnet having an uneven shape without using a mold and without performing cutting or polishing after molding.
In the conventional method, composite particles obtained by kneading a magnetic material powder and a binder in advance are used for powder compression molding or used for injection molding. Therefore, the binder is handled in the state of the composite particles. However, in this embodiment, it is not necessary to mix the magnetic powder and the binder in advance, so that the binder can be ejected as droplets. What is necessary is just to be a thing, and the selection range of the material used as a binder is expanded compared with the conventional method.
Furthermore, since an external magnetic field is applied to a magnetic material having magnetic anisotropy in a state where the magnetic powder 11a can flow, it is brought into contact with the binder, so that the easy magnetization axis directions of the individual magnetic powders 11a are aligned. A magnet that can be fixed and has excellent magnetic field directivity can be obtained.
[0026]
In the above-described embodiment, the precursor is obtained by curing the binder after completing the lamination of all the layers constituting the magnet, but when an ultraviolet curable resin is used as the binder, 1 is used. It is necessary to cure the binder by irradiating with ultraviolet rays every time a layered body is formed.
In this case, since each layer is securely fixed in a state where the magnetization easy axis directions of the magnetic powder are aligned, it is particularly effective in improving the magnetic field directivity of the magnet.
[0027]
In the above embodiment, a magnetic material having magnetic anisotropy is used. However, a magnet can be formed in the same manner using a magnetic material having magnetic isotropy. However, when the magnetic material has magnetic isotropy, the excitation step need not be performed, and the magnetic field generators 6 and 6 in the manufacturing apparatus may not be used.
[0028]
Further, the easy magnetization axis directions of the individual magnetic powders constituting the magnet may not be uniform for all the magnetic powders.
For example, if the direction of the magnetic field applied to the powder layer in an arbitrary excitation process among the excitation processes performed a plurality of times is different from the previous excitation process, the interface of the divided bodies constituting the magnet As a boundary, a magnet in which the magnetization easy axis direction of the magnetic powder is different between the upper layer and the lower layer of the boundary can be manufactured.
Or, for example, in an arbitrary excitation process among a plurality of excitation processes, a magnetic field in the X direction is applied to a part of the powder layer, and a magnetic field in the Z direction is applied to the other parts. By manufacturing the magnet including the divided body in which the magnetization easy axis direction of the magnetic powder is different in different parts in one divided body by changing the direction of the magnetic field for each part in the powder layer for each layer. Can do.
[0029]
Further, the plurality of divided bodies constituting the magnet may not be made of the same magnetic powder.
For example, magnetic powder having a composition different from that of the previous powder layer forming step may be used in the powder layer forming step of arbitrary times among the powder layer forming steps performed a plurality of times. A magnet having different magnetic powder compositions between the upper layer and the lower layer of the boundary can be manufactured with the interface of the divided bodies constituting the boundary.
In the present embodiment, an example is shown in which a magnet is manufactured using a powder magnet. However, the present invention is not limited to this, and if there is no need for excitation, for example, a metal structure using metal powder. The present invention can also be applied to a process of manufacturing a structure or a structure made of a plastic resin.
[0030]
【The invention's effect】
As described above, according to the present invention, a complex-shaped structure can be manufactured without using a mold. Particularly in the case of magnet manufacture, a magnet having excellent magnetic field directivity can be manufactured using a magnetic material having magnetic anisotropy.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a magnet manufacturing apparatus according to the present invention.
FIGS. 2A and 2B show a powder layer forming step and an excitation step in an embodiment of the magnet manufacturing method of the present invention, wherein FIG. 2A is a perspective view, and FIG. 2B is a BB line in FIG. FIG.
FIGS. 3A and 3B show a binder discharge step in an embodiment of the magnet manufacturing method of the present invention, wherein FIG. 3A is a perspective view, and FIG. 3B is a schematic cross-sectional view taken along line BB in FIG. is there.
FIG. 4 is a schematic cross-sectional view showing a precursor forming step in an embodiment of the magnet manufacturing method of the present invention.
[Explanation of symbols]
1 Base 1a Concave portion (layer formation region)
1b Bottom 4 Head (Discharge means)
6 Magnetic field generation means (excitation means)
11, 12, 13, 14 Powder layer 11a Magnetic powder (powdered magnetic material)
21, 22, 23, 24

Claims (4)

A powder layer forming step of forming a powder layer made of a powdered magnetic material having magnetic anisotropy;
An excitation step of applying a magnetic field to the powder layer;
A binder discharge step of discharging droplets containing a binder to the powder layer;
The powder layer forming step, the excitation step, and the binder discharging step are repeated a plurality of times to sequentially laminate the powder layer, and a precursor forming step of forming a magnetic precursor,
A method of manufacturing a magnetic material, wherein a magnetic field having a direction different from that of other excitation steps is applied at least once among the excitation steps performed a plurality of times. A powder layer forming step of forming a powder layer made of a powdered magnetic material having magnetic anisotropy;
An excitation step of applying a magnetic field to the powder layer;
A binder discharge step of discharging droplets containing a binder to the powder layer;
The powder layer forming step, the excitation step, and the binder discharging step are repeated a plurality of times to sequentially laminate the powder layer, and a precursor forming step of forming a magnetic precursor,
A method of manufacturing a magnetic material, wherein at least one of the excitation steps performed a plurality of times, different magnetic fields are applied to different portions of a region of the powder layer from which the binder is discharged.   The powder layer is formed so as to have a thickness different from that of other powder layer forming steps in at least one of the powder layer forming steps performed a plurality of times. Of manufacturing a magnetic material.   4. The powder layer is formed using a magnetic material different from other powder layer forming steps in at least one of the powder layer forming steps performed a plurality of times. A method for producing a magnetic material according to claim 1.

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