JP7399005B2 - Flying object, non-destructive testing equipment, and method for manufacturing flying object - Google Patents

Description

The present invention relates to a flying object, a nondestructive testing device, and a method for manufacturing a flying object.

In recent years, concrete spalling accidents caused by aging deterioration, erosion, etc. have become a social problem in concrete structures such as bridges and tunnels. Therefore, there is a need to develop a device that can accurately evaluate defects in structures.

For example, in Patent Document 1, a nozzle for flying a projectile object using compressed air is provided, and the distance between the tip of the nozzle and the surface of a concrete structure into which elastic waves are input is set at a constant distance, and the axis of the nozzle is An elastic wave input device has been proposed that includes a jig that can be installed so that the structure is at a constant angle with respect to the surface of a structure into which elastic waves are input. It is also described that the flying object is made of aluminum or titanium.

Japanese Patent Application Publication No. 2003-83942

However, if a flying object is made of aluminum or titanium and falls onto a riverbed or seabed after colliding with a structure, it cannot be assimilated into riverbed or seabed sediments because it is a metal, and it remains as a source of pollution. There was a problem that the burden on the environment was large.

Another problem is that metals have high fracture toughness, so even if they collide with a structure, they do not break into pieces and tend to remain as a large source of contamination.

The present invention was devised to solve the above problems, and provides a flying object, a non-destructive testing device, and The object of the present invention is to provide a method for manufacturing a flying object.

The flying object of the present invention is a spherical, bullet-shaped, or cylindrical flying object used for defect inspection of concrete structures, and includes powdered iron, aluminum oxide, silicon oxide, iron oxide, magnesium oxide, and water-containing flying object. It consists of a composite whose main component is at least one of magnesium silicate, titanium carbide, titanium nitride, titanium carbonitride, and ferrite, and whose subcomponent is a thermosetting resin.

The non-destructive inspection device of the present invention includes a flying object having the above configuration, a nozzle into which the flying object is loaded, and using compressed air to fire the flying object from inside the nozzle toward the structure. and a sensor that records the waveform of an elastic wave generated when a body collides with the structure.

The method for manufacturing a flying object of the present invention includes a step of obtaining a molded body using a dry pressure molding device or an injection molding device, a step of firing the molded body to obtain a sintered body, and a step of molding the sintered body into a barrel. and a polishing step.

After colliding with a concrete structure and crushing it, the flying object of the present disclosure is likely to be shattered into pieces and is less likely to impose a burden on the environment.

FIG. 1 is a schematic diagram showing an example of a non-destructive inspection device loaded with a flying object of the present disclosure. (a) is a cross-sectional view, (b) is an enlarged cross-sectional view of part A in (a), and (c) is a cross-sectional view showing an example of a flying object that can be loaded into the non-destructive inspection device shown in FIG. FIG. 3 is an enlarged cross-sectional view of part B in FIG. Another example of a flying object that can be loaded into the non-destructive testing device shown in FIG. 1 is shown in FIG. ) is an enlarged sectional view of section D in (a). It is a photograph taken with an optical microscope of an observation surface obtained by polishing a composite body forming a flying object of the present disclosure. (a) is a front view, and (b) is a bottom view showing another example of a flying object that can be loaded into the non-destructive inspection apparatus shown in FIG. 1. (a) is a front view, and (b) is a bottom view showing another example of a flying object that can be loaded into the non-destructive inspection apparatus shown in FIG. 1. FIG. 1A is a cross-sectional view, and FIG. 1B is an enlarged cross-sectional view of section E in FIG. . FIG. 2A is a cross-sectional view, and FIG. 2B is an enlarged cross-sectional view of section F in FIG. . FIG. 2 is a schematic diagram showing an example of a mold installed in a kneading machine and an injection molding device used to obtain a flying object of the present disclosure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, in all the figures of this specification, unless confusion arises, the same parts are given the same reference numerals, and the explanation thereof will be omitted as appropriate.

FIG. 1 is a schematic diagram showing an example of a non-destructive inspection device loaded with a flying object according to the present disclosure.

The nondestructive inspection device 40 shown in FIG. 1 is a device for evaluating defects in a concrete structure 32, and includes a flying object 10 used for defect inspection of the structure 32, and a nozzle 31 into which the flying object 10 is loaded. , a sensor 33 that shoots a flying object 10 toward a structure 32 from inside a nozzle 31 using compressed air and records the waveform of an elastic wave generated when the flying object 10 collides with the structure 32. Become.

As shown in FIG. 1, a plurality of nozzles 31 are attached to the arm 34 at predetermined intervals. In the example shown in FIG. 1, six nozzles 31 are attached to the arm 34, but the number may be, for example, four to eight. The arm 34 is elongated, and has a length of, for example, 1.5 m to 2.5 m, and the nozzles 31 are attached to the arm 34 at intervals of 0.3 m to 0.4 m. The arm 34 is supported by a cylindrical support member 35 for supplying compressed air. Further, the arm 34 has an internal space 34a into which a pipe 36 is inserted, and compressed air is supplied to the nozzle 31 through the support member 35 and the pipe 36. An electromagnetic valve 37 is attached to the connection portion of the piping 36 to each nozzle 31, and supply of compressed air to the nozzle 31 is started or stopped by remotely controlling the electromagnetic valve 37. A lead wire (not shown) for operating the electromagnetic valve 37 is housed in the internal space 34a.

When the electromagnetic valve 37 is opened, the flying object 10 is launched from the nozzle 31 toward the structure 32 and inputs an elastic wave to the structure 32 .

In the case of the structure shown in FIG. 1, since a plurality of nozzles 31 are attached to the arm 34, for example, the flying object 10 is sequentially fired from the left end nozzle 31 toward the right end nozzle 31 at predetermined time differences. An elastic wave can be input to the object 32.

The sensor 33 records the waveform of an elastic wave, and for example, a contact type accelerometer, a non-contact type laser displacement meter, etc. can be used.

The sensor 33 is connected to an amplifier that amplifies a weak analog signal, an A/D converter that converts the analog signal to a digital signal, a waveform recording device (none of which is shown) that records the waveform as a digital signal, and the like.

FIG. 2 shows an example of a flying object that can be loaded into the non-destructive testing device shown in FIG. (c) is an enlarged sectional view of part B in (a).

FIG. 3 shows another example of a flying object that can be loaded into the non-destructive testing device shown in FIG. (c) is an enlarged sectional view of portion D in (a).

The flying objects 10A and 10B shown in FIGS. 2 and 3 are both spherical and contain powdered iron, aluminum oxide, silicon oxide, iron oxide, magnesium oxide, hydrous magnesium silicate (talc), titanium carbide, titanium nitride, It consists of a composite whose main component is at least one of titanium carbonitride and ferrite, and whose subcomponent is a thermosetting resin. The flying objects 10A and 10B have a diameter of, for example, 8 mm or more and 12 mm or less.

The flying object may have a bullet shape or a cylindrical shape other than a spherical shape.

Since the flying objects 10A and 10B are composed of the above-mentioned composites, when the flying objects 10A and 10B collide with the structure 32 and are crushed, the powdery main component is easily shattered, and moreover, it is a subcomponent with respect to the main component. Since the thermosetting resin acts as a binding force, scattering becomes difficult. Moreover, since the thermosetting resin acts to bond the main components together in the process of molding the flying object, it is possible to improve the shape retention of the molded object.

Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin, urea resin, unsaturated polyester resin, polyimide resin, furan resin, polybutadiene resin, ionomer resin, EEA resin, AAS resin (ASA resin), AS resin, ACS resin, ethylene acetate copolymer, ethylene vinyl alcohol copolymer resin, ABS resin, vinyl chloride resin, chlorinated polyethylene resin, cellulose acetate resin, fluororesin, polyacetal resin, polyamide resin 6, 66, polyamide resin 11, 12, Polyarylate resin, thermoplastic polyurethane elastomer, liquid crystal polymer, polyetheretherketone, polysulfone resin, polyethersulfone resin, high density polyethylene, low density polyethylene, linear low density polyethylene, polyethylene terephthalate, polycarbonate resin, polystyrene resin, These include polyphenylene ether resin, polyphenylene sulfide resin, polybutadiene resin, polypropylene resin, methacrylic resin, methylpentene polymer, MMA resin, vinyl ester resin, photocurable resin, and the like. It may also contain wax or glycerin.

The wax is at least one of fatty acid ester, fatty acid amide, phthalate ester, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, carnauba wax, montan wax, urethanized wax, maleic anhydride modified wax, and polyglycol compound. That's it.

The components constituting the complex are then identified using an X-ray diffraction device. The content of each component may be determined by analyzing a spectrum obtained by an X-ray diffraction device using the Rietveld method. The main component in the present disclosure refers to a component that exceeds 50% by mass out of the total 100% by mass of components constituting the composite. The content of components that do not constitute a complex, such as unavoidable metal impurities, may be determined using a fluorescent X-ray analyzer or an ICP emission spectrometer.

The thermosetting resin is preferably connected in a network inside the composite.

If the thermosetting resin is connected in a network inside the composite, the main component will be dispersed to the inside of the flying objects 10A and 10B, so the powdery main component will be more likely to shatter. , it becomes easier to assimilate into riverbed and seabed sediments.

The surface layer of the composite may be denser than the interior.

If the surface layer is denser than the inside, the mechanical strength of the surface layer will be higher, making it easier to load the flying objects 10A, 10B into the nozzle 31.

Here, when the projectile is spherical, the surface layer refers to an area within 10% of the diameter of the projectile in the depth direction from the spherical surface 10a toward the center, and the inside refers to the area excluding the surface layer. Refers to an area.

The relative densities of the surface layer portion and the interior portion may be determined based on the Archimedes method.

The difference in relative density between the surface layer portion and the inside portion is, for example, 2% or more.

FIG. 4 is a photograph taken with an optical microscope of an observation surface obtained by polishing the composite body forming the flying object of the present disclosure.

As shown in FIG. 4, the composite has a plurality of pores 17, which are dispersed.

For example, the average equivalent circle diameter of the pores 17 included in the composite is 1 μm or more and 4 μm or less, and the area occupation rate of the pores 17 is 8% or more and 16% or less.

The kurtosis Ku of the equivalent circle diameter of the pores 17 may be 20 or more and 30 or less.

When the kurtosis Ku of the circle-equivalent diameter of the pores 17 is within this range, variations in the diameter of the pores 17 are considerably suppressed, so that locally low mechanical strength areas are reduced, and the loading into the nozzle 31 is further improved. It becomes easier.

The average value of the equivalent circle diameter, the area occupation rate, and the kurtosis Ku of the pores 17 can be determined by the following method.

First, the composite is sequentially polished with water-resistant abrasive paper having particle sizes of P320 and P600 as defined in JIS R 6010:2000.

After polishing with waterproof abrasive paper is completed, polishing is performed using a slurry containing diamond abrasive grains having an average particle size of 9 μm, and then using a slurry containing diamond abrasive grains having an average particle size of 3 μm.
After these polishing steps are completed, an observation surface is obtained by polishing using a slurry containing alumina abrasive grains having an average grain size of 0.05 μm. Note that the composite may be filled with resin in advance and then polished.

Observe the observation surface at a magnification of 100x to 200x and select an average range, such that the area is 0.354 mm ² (horizontal length 687 μm, vertical length 515 μm). An observation image is obtained by photographing the area with a CCD camera.

By analyzing this observed image using image analysis software (for example, Win ROOF, manufactured by Mitani Shoji Co., Ltd.), the equivalent circle diameter of each pore 17 can be determined.

In the analysis, the threshold value of the equivalent circle diameter of the pores 17 is set to 0.868 μm, and the equivalent circle diameter less than 0.868 μm is not subject to the average value, area occupation rate, and kurtosis.

Here, kurtosis Ku is an index (statistic) that indicates how much the peak and tail of the distribution differ from the normal distribution, and if kurtosis Ku > 0, it has a sharp peak and a long thick tail. If the kurtosis Ku=0, the distribution becomes a normal distribution; if the kurtosis Ku<0, the distribution becomes a distribution with a rounded peak and a short, thin tail.

Note that the kurtosis Ku of the circle-equivalent diameter of the pores 17 may be determined using the function KURT provided in Excel (registered trademark, Microsoft Corporation).

At least the surface layer portion of the composite may be colored.

If the surface layer is colored, it becomes easier to identify the markings on the structure 32 caused by the impact of the flying objects 10A and 10B, and it becomes easier to set the next target for the structure 32.

The composite may contain a liquid marking agent at least within the closed pores.

When a liquid marking agent is contained in the closed pores, identification of the marking becomes easier and misrecognition can be suppressed.

Examples of the marking agent include methyl blue, methyl red, methyl orange, methyl yellow, and methyl violet.

The flying object 10A shown in FIG. 2 is made of a spherical body, and includes a flange 11 extending radially outward and a recess 12 concave radially inward. The recessed portion 12 includes a first recessed portion 12a having an outer peripheral surface 12d curved in a concave shape, a second recessed portion 12b connected to the first recessed portion 12a and having an inclined outer peripheral surface 12e, and a second recessed portion 12b having an inclined outer peripheral surface 12e. A third recessed portion 12c is connected to the second recessed portion 12b and has an outer peripheral surface 12f curved in a concave shape.

The flying object 10A preferably includes a plurality of flanges 11 extending outward in the radial direction of the spherical body and at least a plurality of concave portions 12g and 12h recessed inward in the radial direction.

With such a configuration, there is an intersection 11e between the annular surface 11c of the flange 11 and the side surface 11d, which is likely to become a starting point for cracks, or an intersection 11e between the spherical surface 10a and the outer circumferential surface 12d of the first recessed portion 12a. Since a first boundary surface 13a located between the first boundary surface 13a and a second boundary surface 13b located between the spherical surface 10a and the outer circumferential surface 12f of the third recessed portion 12c are formed, it becomes easy to miniaturize the crushed pieces. .

Further, the flange portion 11 and the recessed portions 12g and 12h are preferably located parallel to each other.

With such a configuration, the straightness of the flying object 10A is increased, so the accuracy of hitting is improved.

The flying object 10B shown in FIG. 3 is made of a spherical body, and includes a central flange 11a located at the center of the spherical body, and lateral flanges 11b on both sides of the central flange 11a.

With such a configuration, the first intersection 11e between the annular surface 11c of the central flange 11a and the side surface 11d and the second intersection 11e between the annular surface 11f and the side surface 11g of the side flange 11b tend to become the starting point for cracks. Since the intersection 11h exists, it becomes easy to refine the crushed pieces.

Although the flying object 10B includes the side flange 11b, the lateral flange 11b may be replaced with a lateral recess.

Although the flying objects 10A and 10B shown in FIGS. 2 and 3 are both spherical bodies having a flange 11, the flying objects may be spheroidal or true spherical.

5 and 6 show other examples of flying objects that can be loaded into the non-destructive testing apparatus shown in FIG. 1. (a) is a front view, and (b) is a bottom view.

The flying object 10C shown in FIG. 5 is a bullet-shaped body including a cylindrical base 13a and a tip 13b that is connected to the base 13a and becomes thinner toward the tip. , a plurality of inclined grooves 15 are provided on the outer peripheral surface 13c.

The inclination angle of the flying object 10C with respect to the axis is, for example, 10° or more and 30° or less.

The flying object 10D shown in FIG. 6 is a bullet-shaped body that includes a cylindrical base 14a and a tip 14b that is connected to the base 14a and becomes thinner toward the tip side, and is opposite to the traveling direction of the bullet-shaped body. A cross-shaped blade 16 is provided at the rear end.

When the flying object is cylindrical or bullet-shaped, the surface layer refers to an area within 10% of the diameter of the bases 13a, 14a in the depth direction from the outer circumferential surfaces 13c, 14c toward the center; refers to the area excluding the surface layer.

If the flying object has the structure shown in FIGS. 2, 3, 5, and 6, the straightness of each flying object will be high, and the accuracy of the flying object will be improved.

Next, an example of a method for manufacturing a flying object according to the present disclosure will be described.

First, a powder of at least one of iron, aluminum oxide, silicon oxide, iron oxide, titanium carbide, titanium nitride, titanium carbonitride, and ferrite is mixed with a thermosetting resin, and then spray-dried to obtain granules. These granules are a powder for molding, and a molded body is obtained from the granules using a molding apparatus shown in FIGS. 7 to 9. This will be explained in detail below using figures.

Figure 7 shows an example of the main parts of a dry pressure molding device used to obtain the flying object shown in Figure 1. (a) is a cross-sectional view, and (b) is an enlarged view of section E in (a). FIG.

The dry pressure molding device 40 includes a first bowl-shaped curved surface 41a and a first bowl-shaped curved surface 41a connected to the first bowl-shaped curved surface 41a.
a cylindrical first upper punch 41 having an inclined surface 41b; a concave first annular curved surface 42a; and a second concave annular curved surface 42a connected to one end of the first annular curved surface 42a. an upper punch set 43 having a cylindrical second upper punch 42 having an inclined surface 42b and a downward surface 42c connected to the other end of the first annular curved surface; arranged vertically symmetrically with the upper punch set 43; and a cylindrical first lower punch 44 having a second bowl-shaped curved surface 44a and a third inclined surface (not shown) connected to the second bowl-shaped curved surface 44a, and on the outer peripheral side of the first lower punch 44, A concave second annular curved surface 45a, a fourth inclined surface (not shown) connected to one end of the second annular curved surface 45a, and an upward surface 45c connected to the other end of the second annular curved surface 45a. A cylindrical second lower punch 45 and a lower punch set 46 are provided. By the first bowl-shaped curved surface 41a of the first upper punch 51, the first annular curved surface 42a of the second upper punch 42, the second bowl-shaped curved surface 44a of the first lower punch 44, and the second annular curved surface 45a of the second lower punch 45. After filling the enclosed spherical internal space 47 with molding powder 48, the molding powder 48 is pressurized to obtain a molded body. By using the dry pressure molding apparatus 40, it is possible to obtain a molded body having a flange extending radially outward of the spherical body and a plurality of concave portions recessed radially inward.

FIG. 8 shows another example of the main parts of the dry pressure molding apparatus used to obtain the flying object shown in FIG. FIG. 3 is an enlarged cross-sectional view.

The dry pressure molding device 50 includes a cylindrical first upper punch 51 having a first bowl-shaped curved surface 51a and a first annular plane 51b connected to the first bowl-shaped curved surface 51a, and an outer periphery of the first upper punch 51. an upper punch set 53 having a cylindrical second upper punch 52 having a first concave annular curved surface 52a and a second annular plane 52b connected to the first annular curved surface 52a on the side; a cylindrical first lower punch 54 which is arranged vertically symmetrically and has a second bowl-shaped curved surface 54a and a third annular plane (not shown) connected to the second bowl-shaped curved surface 54a; A lower punch having a cylindrical second lower punch 55 having a concave second annular curved surface 55a, a fourth annular plane 55b connected to the second annular curved surface 55a, and a fourth annular plane 55b on the outer peripheral side of the lower punch. A set 56 is provided. By the first bowl-shaped curved surface 51a of the first upper punch 51, the first annular curved surface 52a of the second upper punch 52, the second bowl-shaped curved surface 54a of the first lower punch 54, and the second annular curved surface 55a of the second lower punch 55. After filling the enclosed spherical internal space 57 with molding powder 58, the molding powder 58 is pressurized to obtain a molded body. By using the dry pressure molding apparatus 50, it is possible to obtain a molded body that includes a central flange located at the center of the spherical body and side flange portions on both sides of the central flange symmetrically.

When the dry pressure molding devices 40 and 50 are used, the molding pressure due to pressurization is, for example, 24.5 MPa or more and 34.5 MPa or less.

Here, in order to obtain a flying object in which the surface layer of the composite is denser than the inside, the molding pressure may be set to 24.5 MPa or more and 30 MPa or less. FIG. 9 is a schematic diagram showing an example of a mold installed in a kneading machine and an injection molding apparatus used to obtain a flying object of the present disclosure.

First, powder of at least one of iron, aluminum oxide, silicon oxide, iron oxide, titanium carbide, titanium nitride, titanium carbonitride, and ferrite and a thermosetting resin are kneaded using a kneader 60. The kneader 60 may be either a batch kneader or a continuous kneader. Pellets 61 obtained by kneading are supplied from a supply port 71 of an injection molding device (not shown) toward a spherical internal space 73 of a mold 72 comprising an upper mold 72a and a lower mold 72b, and are formed into a spherical molded body. molded. Note that a gas vent (not shown) is preferably formed inside the mold 72 to exhaust gas generated within the mold 72 to the outside.

The molded body obtained by the above-mentioned molding apparatus can be impregnated with a liquid marking agent as necessary and then heat-treated at, for example, 130° C. to 170° C. for 3 to 6 hours to form a composite. .

In order to obtain a flying object in which the kurtosis Ku of the circular equivalent diameter of the pores contained in the composite is 20 or more and 30 or less, heat treatment may be performed at 150° C. to 170° C. for 3 hours to 6 hours.

Then, by barrel polishing the composite, burrs remaining on the spherical surface of the composite can be removed, and the flying object of the present disclosure can be obtained.

10A to 10D Flying object 11 Flange 12 Recessed part 13a Base 13b Tip 14a Base 14b Tip 15 Groove 16 Vane 17 Air hole 31 Nozzle 32 Structure 33 Sensor 34 Arm 35 Support member 36 Piping 40 Dry pressure molding device 41 1 upper punch 42 2nd upper punch 43 Upper punch set 44 1st lower punch 45 2nd lower punch 46 Lower punch set 47 Spherical internal space 48 Molding powder 50 Dry pressure molding device 51 1st upper punch 52 2nd upper punch 53 Upper punch set 54 First lower punch 55 Second lower punch 56 Lower punch set 57 Spherical internal space 58 Molding powder 60 Kneading machine 61 Pellet 71 Supply port 72 Molding mold

Claims (15)

A spherical, bullet-shaped, or cylindrical flying object used for defect inspection of concrete structures, containing powdered iron, aluminum oxide, silicon oxide, iron oxide, magnesium oxide, hydrous magnesium silicate, titanium carbide, and nitride. A flying object made of a composite whose main component is at least one of titanium, titanium carbonitride, and ferrite, and whose subcomponent is a thermosetting resin. The flying object according to claim 1, wherein the thermosetting resin is connected in a network inside the composite. The flying object according to claim 1 or 2, wherein the surface layer of the composite is denser than the interior. The flying object according to any one of claims 1 to 3, wherein the kurtosis Ku of the equivalent circle diameter of the pores included in the composite is 20 or more and 30 or less. The composite body is made of a spherical body, and the spherical body has a plurality of at least one of a flange extending radially outward and a plurality of concave portions concave radially inward. The flying object according to any one of 1 to 4. The flying object according to claim 5, wherein the flange portion and the recessed portion are located parallel to each other. According to claim 6, the spherical body has a central flange located at the center of the spherical body, and lateral flange parts or lateral recessed parts on both sides of the central flange symmetrically. The stated flying object. The flying object according to any one of claims 1 to 4, wherein the composite body is made of a bullet-shaped body and has a plurality of grooves on its outer peripheral surface that are inclined with respect to the axial direction of the bullet-shaped body. The flight according to any one of claims 1 to 4 or claim 8, wherein the composite body is made of a bullet-shaped body, and the bullet-shaped body is provided with cross-shaped wings at a rear end portion opposite to the traveling direction of the bullet-shaped body. body. The flying object according to any one of claims 1 to 9, wherein at least a surface layer portion of the composite is colored. The flying object according to any one of claims 1 to 10, wherein the composite contains a liquid marking agent at least in closed pores. The flying object according to any one of claims 1 to 11, a nozzle into which the flying object is loaded, the flying object being launched from the inside of the nozzle toward the structure using compressed air, and the flying object is A non-destructive inspection device equipped with a sensor that records the waveform of elastic waves generated when a structure collides with the structure. The method for producing a flying object according to any one of claims 1 to 11, comprising the steps of obtaining a molded body using a dry pressure molding device or an injection molding device, and heat-treating the molded body to obtain a composite body. and barrel polishing the composite. The dry pressure forming apparatus includes a cylindrical first upper punch having a first bowl-shaped curved surface and a first inclined surface connected to the first bowl-shaped curved surface, and an outer peripheral side of the first upper punch, A cylindrical first surface having a concave first annular curved surface, a second inclined surface connected to one end of the first annular curved surface, and a downward facing surface connected to the other end of the first annular curved surface. an upper punch set having a second upper punch, and a cylindrical upper punch set arranged vertically symmetrically with the upper punch set and having a second bowl-shaped curved surface and a third inclined surface connected to the second bowl-shaped curved surface. a first lower punch; and a second concave annular curved surface on the outer peripheral side of the first lower punch;
A lower cylindrical lower punch having a fourth inclined surface connected to one end of the second annular curved surface and an upward surface connected to the other end of the second annular curved surface. a punch set, a first bowl-shaped curved surface of the first upper punch, a first annular curved surface of the second upper punch, a second bowl-shaped curved surface of the first lower punch, and a second annular curve of the second lower punch. 14. The method for manufacturing a flying object according to claim 13, wherein the spherical internal space surrounded by the curved surface is filled with molding powder, and then the molding powder is pressurized. The dry pressure molding device includes a cylindrical first upper punch having a first bowl-shaped curved surface and a first annular plane connected to the first bowl-shaped curved surface, and an outer peripheral side of the first upper punch, an upper punch set having a cylindrical second upper punch having a first concave annular curved surface and a second annular plane connected to the first annular curved surface; arranged vertically symmetrically with the upper punch set; a cylindrical first lower punch having a second bowl-shaped curved surface and a third annular plane connected to the second bowl-shaped curved surface; a concave second annular curved surface on the outer peripheral side of the first lower punch; a cylindrical second lower punch having a third annular plane connected to the second annular curved surface; After filling the spherical internal space surrounded by the first annular curved surface, the second bowl-shaped curved surface of the first lower punch, and the second annular curved surface of the second lower punch with molding powder, the molding powder is processed. The method for manufacturing a flying object according to claim 13, wherein the flying object is compressed.

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