Acoustic vibration member and method for manufacturing the same

Abstract

The present invention provides a method for manufacturing an acoustic vibration member made of a resin material and adjusted to a predetermined natural frequency and vibration mode, and the acoustic vibration member. [Solution] A method for manufacturing an acoustic vibration member, comprising the steps of: creating three-dimensional CAD data of an acoustic vibration member on a computer; predicting the natural frequency and vibration mode of the acoustic vibration member based on a model obtained by dividing the three-dimensional CAD data into finite elements; modifying the three-dimensional CAD data in accordance with the predicted natural frequency and vibration mode of the acoustic vibration member and determining the shape of the acoustic vibration member; additively manufacturing the acoustic vibration member based on the determined shape of the acoustic vibration member; measuring the natural frequency and vibration mode of the additively manufactured acoustic vibration member; and post-processing the acoustic vibration member so that the acoustic vibration member has a predetermined natural frequency and vibration mode in accordance with the measured natural frequency and vibration mode.

Description

[Technical Field]

[0001] The present disclosure relates to an acoustic vibration member and a method for manufacturing an acoustic vibration member. [Background technology]

[0002] 2. Description of the Related Art Conventionally, acoustic vibration members made of resin materials are known as acoustic vibration members that do not use metal or glass materials.

[0003] Patent Document 1 discloses "an acoustic vibration component made of a resin material that generates sound by vibrating, and whose loss tangent (tanδ) at 25°C and a frequency of 100 Hz, as determined by dynamic solid viscoelasticity, is 0.030 or less." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-215453 Summary of the Invention [Problem to be solved by the invention]

[0005] Compared to acoustic vibration members made of metal or glass materials, acoustic vibration members made of the above resin materials have advantages such as being lightweight, highly moldable, less likely to break, and easier to color. They also produce pure tones (sounds consisting of a single frequency) and can produce beautiful tones.

[0006] However, until now, there has been no known method for adjusting an acoustic vibration member made of a resin material to a predetermined natural frequency and vibration mode, and for easily manufacturing such an adjusted acoustic vibration member, and as a result, acoustic vibration members made of a resin material have not been able to fully demonstrate their acoustic effects.

[0007] An object of one embodiment of the present disclosure is to provide a method for manufacturing an acoustic vibration member that is made of a resin material and is adjusted to a predetermined natural frequency and vibration mode, and that has excellent acoustic effects. [Means for solving the problem]

[0008] The means for solving the above problems include the following aspects. <1> A method for manufacturing an acoustic vibration member, comprising the steps of: creating three-dimensional CAD data of an acoustic vibration member on a computer; predicting a natural frequency and vibration mode of the acoustic vibration member based on a model obtained by finite element division of the three-dimensional CAD data; modifying the three-dimensional CAD data in accordance with the predicted natural frequency and vibration mode of the acoustic vibration member and determining a shape of the acoustic vibration member; additively manufacturing the acoustic vibration member based on the determined shape of the acoustic vibration member; measuring the natural frequency and vibration mode of the additively manufactured acoustic vibration member; and post-processing the acoustic vibration member so that the acoustic vibration member has a predetermined natural frequency and vibration mode in accordance with the measured natural frequency and vibration mode. <2> The acoustic vibration member includes a thermoplastic resin. <1> A method for manufacturing the acoustic vibration member according to claim 1. <3> the acoustic vibration member includes a thermoplastic resin, the thermoplastic resin includes a cyclic olefin polymer, and the cyclic olefin polymer includes at least one selected from a copolymer of ethylene or an α-olefin with a cyclic olefin and a ring-opening polymer of a cyclic olefin; <1> or <2> A method for manufacturing the acoustic vibration member according to claim 1. <4> An acoustic vibration member comprising a thermoplastic resin, the thermoplastic resin including a cyclic olefin polymer, the cyclic olefin polymer including at least one selected from a copolymer of ethylene or an α-olefin with a cyclic olefin, and a ring-opening polymer of a cyclic olefin, the acoustic vibration member having a hollow portion and an opening at least at one end of the hollow portion. <5> The volume of the hollow portion occupies 60% or more of the volume of the acoustic vibration member. <4> The acoustic vibration member according to claim 1. <6> having an opening at only one end, <4> or <5> The acoustic vibration member according to claim 1. <7> The tube has openings at one end and the other end, and the diameter of the opening at the one end is larger than the diameter of the opening at the other end. <4> or <5> The acoustic vibration member according to claim 1. <8> It has a laminated structure of an uncolored layer and a layer colored with one or more colorants. <4> ~ <7> 10. An acoustic vibration member according to any one of the preceding claims. <9> The scale was adjusted <4> ~ <8> 10. An acoustic vibration member according to any one of the preceding claims. [Effects of the Invention]

[0009] According to one embodiment of the present disclosure, there is provided a method for manufacturing an acoustic vibration member made of a resin material and adjusted to a predetermined natural frequency and vibration mode, and an acoustic vibration member having excellent acoustic effects. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of the shape of an acoustic vibration member according to the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing another example of the shape of the acoustic vibration member of the present disclosure. [Figure 3] FIG. 3 is a schematic diagram showing another example of the shape of the acoustic vibration member of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram showing another example of the shape of the acoustic vibration member of the present disclosure. [Figure 5] FIG. 5 is a schematic diagram showing another example of the shape of the acoustic vibration member of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present disclosure, in the numerical ranges described in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with the value shown in the examples. In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0012] <Method of manufacturing acoustic vibration member> The method for manufacturing an acoustic vibration member according to the present disclosure includes the steps of: creating three-dimensional CAD data of the acoustic vibration member on a computer; and predicting the natural frequency and vibration mode of the acoustic vibration member based on a model obtained by finite element division of the three-dimensional CAD data (hereinafter also referred to as the "natural frequency and vibration mode prediction step"); modifying the three-dimensional CAD data in accordance with the predicted natural frequency and vibration mode of the acoustic vibration member to determine the shape of the acoustic vibration member (hereinafter also referred to as the "shape determination step"); additively manufacturing the acoustic vibration member based on the determined shape of the acoustic vibration member (hereinafter also referred to as the "additive manufacturing step"); measuring the natural frequency and vibration mode of the additively manufactured acoustic vibration member (hereinafter also referred to as the "natural frequency and vibration mode measurement step"); and post-processing the acoustic vibration member in accordance with the measured natural frequency and vibration mode so that the acoustic vibration member has a predetermined natural frequency and vibration mode (hereinafter also referred to as the "post-processing step").

[0013] By including the above steps, it is possible to manufacture an acoustic vibration member made of a resin material and adjusted to a predetermined natural frequency and vibration mode. In this disclosure, the term "acoustic vibration member" includes wind chimes, bells, musical instruments, etc.

[0014] The following explains each in order.

[0015] - Natural frequency and vibration mode prediction process - First, in the natural frequency and vibration mode prediction process, 3D CAD data of the acoustic vibration component is created on a computer. The 3D CAD data may be a model that reproduces the layered structure, or a model that does not. A model that reproduces the layered structure will provide higher prediction accuracy, but from the perspective of efficient shape consideration, a simple model that does not reproduce the layered structure is preferable.

[0016] Although there are no particular limitations on the shape of the acoustic vibration member, a structure having a hollow portion is preferable, as the acoustic vibration member can be easily adjusted to a predetermined natural frequency and vibration mode by having a hollow portion.

[0017] The structure having a hollow portion may have an opening at at least one end of the hollow portion, and the volume of the hollow portion may occupy 60% or more of the volume of the acoustic vibration member.

[0018] Specific shapes of the acoustic vibration member include a bell shape, a gourd shape, a cylinder shape, a rectangular cylinder shape, a truncated pyramidal cylinder shape, and a truncated conical cylinder shape.

[0019] The acoustic vibration member may have an opening only at one end, or may have openings at both ends. When the acoustic vibration member has openings at both ends, the diameter of the opening at one end may be larger than the diameter of the opening at the other end.

[0020] When creating the three-dimensional CAD data, the size (length, width, height) and thickness of the acoustic vibration member may be determined arbitrarily in the initial stage.

[0021] Next, the natural frequency and vibration mode of the acoustic vibration component are predicted based on a model obtained by dividing the three-dimensional CAD data into finite elements.

[0022] The natural frequency and vibration mode of an acoustic vibration component can be predicted by converting the 3D CAD data of the created acoustic vibration component into a model (mesh model) that can be analyzed by finite element method (FEM), and then performing eigenvalue analysis (modal analysis).Finite element analysis can be performed using finite element analysis software.

[0023] In the finite element (FEM) analysis, the finite element division may be tetrahedral division, hexahedral division, etc. The length of one side of each element may be 1 mm to 7 mm.

[0024] The boundary value conditions can be determined arbitrarily.

[0025] The material characteristic values ​​of the acoustic vibration member to be input may be thickness, Young's modulus (modulus of longitudinal elasticity), Poisson's ratio, density, and the like.

[0026] -Shape determination process- Next, in the shape determination step, the three-dimensional CAD data is modified in accordance with the natural frequency and vibration mode of the acoustic vibration member predicted based on the three-dimensional CAD data of the acoustic vibration member, and the shape of the acoustic vibration member is determined.

[0027] In this process, the 3D CAD data of the acoustic vibration member is modified until the natural frequency and vibration mode of the acoustic vibration member fall within a predetermined allowable range for the natural frequency and vibration mode of the acoustic vibration member. Modifications are made to one or more parameters related to the shape of the acoustic vibration member.

[0028] The parameter that is modified may be the size, height, or thickness of the acoustically vibrating member.

[0029] -Additive manufacturing process- Next, in the additive manufacturing process, the acoustic vibration member is additively manufactured based on the determined shape of the acoustic vibration member.

[0030] In the disclosed method, additive manufacturing is performed using a 3D printer. Using a 3D printer eliminates the need for molds and draft tapers, which are essential for injection molding, and allows for the easy creation of complex three-dimensional shapes that are difficult to mold using injection molding in a short amount of time. This allows for the production of acoustic vibration components tuned to a predetermined natural frequency and vibration mode.

[0031] Additive manufacturing methods using 3D printers include material extrusion (MEX), powder bed fusion (PBF), binder jetting (BJT), directed energy deposition (DED), material jetting (MJT), sheet lamination (SHL), and vat photopolymerization (VPP), etc. Among these, material extrusion (MEX) is preferred from the standpoint of economy and shortening the manufacturing time.

[0032] In the material extrusion method, first, pellet- or filament-shaped additive manufacturing material is inserted into the extrusion head of the 3D printer. The inserted additive manufacturing material is heated and melted by the heating means inside the extrusion head, and is continuously extruded from the nozzle onto the stage. The extruded material is layered on top of the already layered material, and then cools and solidifies, becoming one with it. This results in the additive manufacturing material being modeled three-dimensionally.

[0033] In the method of the present disclosure, from the viewpoint of additive manufacturing using a material extrusion method, it is preferable that the acoustic vibration member contains a thermoplastic resin.

[0034] Examples of thermoplastic resins include polyolefin resins such as polypropylene (PP) resin, polyethylene (PE) resin, and cyclic olefin polymers; polystyrene-based resins such as polystyrene (PS) resin, syndiotactic polystyrene (SPS) resin, high impact polystyrene (HIPS) resin, and acrylonitrile-butylene-styrene copolymer (ABS) resin; polyester-based resins such as polylactic acid (PLA) resin, polyethylene terephthalate (PET) resin, and polybutylene terephthalate (PBT) resin; polyacetal (POM) resin; polycarbonate (PC) resin; polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 46, copolymers of polyamide 6 and polyamide 66 (polyamide 6 / 66), and copolymers of polyamide 6 and polyamide 1. Examples of suitable polyamides include aliphatic polyamide (PA) resins such as copolymers of 2 (polyamide 6 / 12); semi-aromatic polyamide (PA) resins consisting of structural units with aromatic rings and structural units without aromatic rings, such as polyamide MXD6, polyamide MXD10, polyamide 6T, polyamide 9T, and polyamide 10T; polyphenylene sulfide (PPS) resin; polyethersulfone (PES) resin; liquid crystal polyester (LCP) resin; polyether aromatic ketone resins such as polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, and polyether ether ketone ketone (PEEKK) resin; polyetherimide (PEI) resin; polyamide-imide (PAI) resin; and thermoplastic polyimide (TPI) resin.

[0035] As the thermoplastic resin, a cyclic olefin polymer is preferred from the viewpoint of having better acoustic properties.

[0036] Examples of the cyclic olefin polymer include at least one selected from copolymers of ethylene or α-olefins with cyclic olefins, and ring-opening polymers of cyclic olefins.

[0037] As the copolymer of ethylene or α-olefin and cyclic olefin, for example, the polymers described in paragraphs 0030 to 0123 of WO 2008 / 047468 can be used.

[0038] For example, it is a polymer having an alicyclic structure in at least a part of its repeating structural units (hereinafter also simply referred to as "polymer having an alicyclic structure"), and it is sufficient that at least a part of the repeating units of the polymer have an alicyclic structure. Specifically, it is preferable that the polymer includes a polymer having one or more structures represented by the following formula (1):

[0039] [ka]

[0040] In formula (1), x and y represent copolymerization ratios and are real numbers that satisfy the relationship 0 / 100≦y / x≦95 / 5. x and y are expressed on a molar basis. n represents the number of substituents Q and is a real number in the range of 0≦n≦2. R a is a 2+n valent group selected from the group consisting of hydrocarbon groups having 2 to 20 carbon atoms. R b is a hydrogen atom or a monovalent group selected from the group consisting of hydrocarbon groups having 1 to 10 carbon atoms. R c is a tetravalent group selected from the group consisting of hydrocarbon groups having 2 to 10 carbon atoms. Q is COOR d (R d is a hydrogen atom or a monovalent group selected from the group consisting of hydrocarbon groups having 1 to 10 carbon atoms. R a , R b , R c and Q may each be one type, or may each be two or more types in any ratio.)

[0041] In the above formula (1), R ais preferably one or more divalent groups selected from hydrocarbon groups having 2 to 12 carbon atoms, more preferably a divalent group represented by the following formula (2) when n=0, and most preferably a divalent group in which p is 0 or 1 in the following formula (2). a The structure may be used alone or in combination of two or more.

[0042] [ka]

[0043] In formula (2), p is an integer of 0 to 2.

[0044] Furthermore, the copolymer of ethylene or an α-olefin with a cyclic olefin is a cyclic olefin copolymer represented by the following formula (3): For example, it comprises a structural unit (A) derived from ethylene or a linear or branched α-olefin having 3 to 30 carbon atoms, and a structural unit (B) derived from a cyclic olefin.

[0045] [ka]

[0046] In formula (3), R a is a divalent group selected from the group consisting of hydrocarbon groups having 2 to 20 carbon atoms. R b is a hydrogen atom or a monovalent group selected from the group consisting of hydrocarbon groups having 1 to 10 carbon atoms. R a and R b may each be one type, or two or more types may be present in any ratio. x and y represent copolymerization ratios and are real numbers satisfying 5 / 95≦y / x≦95 / 5, preferably 50 / 50≦y / x≦95 / 5, and more preferably 55 / 45≦y / x≦80 / 20. x and y are on a molar basis.

[0047] The copolymer of ethylene or an α-olefin with a cyclic olefin is preferably a copolymer consisting of ethylene and a cyclic olefin, and the cyclic olefin is preferably one or more selected from the group consisting of bicyclo[2.2.1]-2-heptene, tetracyclo[4.4.0.12,5.17,10]-3-dodecene, 1,4-methano-1,4,4a,9a-tetrahydrofluorene, a cyclopentadiene-benzyne adduct, and a cyclopentadiene-acenaphthylene adduct, and more preferably at least one selected from bicyclo[2.2.1]-2-heptene and tetracyclo[4.4.0.12,5.17,10]-3-dodecene. The copolymer of ethylene or an α-olefin with a cyclic olefin may be a polymer having one or more structures represented by the above formula (1) or a polymer obtained by hydrogenating a cyclic olefin copolymer represented by the above formula (3).

[0048] The cyclic olefin polymer may be a ring-opened polymer of a cyclic olefin, such as a ring-opened polymer of a norbornene monomer, a ring-opened polymer of a norbornene monomer and another monomer capable of ring-opening copolymerization with the norbornene monomer, or a hydrogenated product thereof.

[0049] Examples of norbornene-based monomers include bicyclo[2.2.1]hept-2-ene (common name: norbornene) and its derivatives (those with ring substituents), tricyclo[4.3.01,6.12.5]deca-3,7-diene (common name: dicyclopentadiene) and its derivatives, 7,8-benzotricyclo[4.3.0.12.5]dec-3-ene (common name: methanotetrahydrofluorene, also known as 1,4-methano-1,4,4a,9a-tetrahydrofluorene) and its derivatives, and tetracyclo[4.4.0.12,5.17,10]-3-dodecene (common name: tetracyclododecene) and its derivatives. Substituents on the rings of these derivatives include alkyl groups, alkylene groups, vinyl groups, alkoxycarbonyl groups, and alkylidene groups. The substituents may be one or more. Examples of derivatives having a substituent on such a ring include 8-methoxycarbonyl-tetracyclo[4.4.0.12,5.17,10]dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo[4.4.0.12,5.17,10]dodec-3-ene, and 8-ethylidene-tetracyclo[4.4.0.12,5.17,10]dodec-3-ene. These norbornene-based monomers may be used alone or in combination of two or more.

[0050] A ring-opening polymer of a norbornene-based monomer, or a ring-opening polymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization therewith, can be obtained by polymerizing the monomer components in the presence of a known ring-opening polymerization catalyst. Examples of the ring-opening polymerization catalyst that can be used include catalysts composed of a halide of a metal such as ruthenium or osmium, a nitrate or an acetylacetone compound, and a reducing agent; and catalysts composed of a halide or an acetylacetone compound of a metal such as titanium, zirconium, tungsten, or molybdenum, and an organoaluminum compound. Examples of other monomers capable of undergoing ring-opening copolymerization with norbornene-based monomers include monocyclic olefin-based monomers such as cyclohexene, cycloheptene, and cyclooctene.

[0051] A hydrogenated ring-opening polymer of a norbornene-based monomer or a hydrogenated ring-opening polymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization with the norbornene-based monomer can usually be obtained by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to a polymerization solution of the ring-opening polymer and hydrogenating the carbon-carbon unsaturated bonds.

[0052] The thermoplastic resins may be used alone or in combination of two or more.

[0053] When the acoustic vibration member of the present disclosure contains a thermoplastic resin, the content of the thermoplastic resin may be 0.1% by mass to 100% by mass, 1% by mass to 90% by mass, or 10% by mass to 80% by mass relative to the total amount of the acoustic vibration member.

[0054] The acoustic vibration member may contain additives as long as they do not impair the effects of the present disclosure. Examples of additives include one or more additives selected from the group consisting of heat stabilizers, weather stabilizers, radiation resistant agents, plasticizers, lubricants, release agents, nucleating agents, friction and wear improvers, flame retardants, foaming agents, antistatic agents, colorants, anti-fogging agents, anti-blocking agents, impact resistance agents, surface wetting improvers, fillers, hydrochloric acid absorbers, and metal deactivators.

[0055] When the acoustic vibration member contains an additive, the content of the additive can be selected appropriately depending on the application, as long as the effects of the present disclosure are not impaired. If the content of the additive is high, additive manufacturing of the acoustic vibration member by the material extrusion method may become difficult due to clogging of the extrusion head, etc.

[0056] When an acoustic vibration member contains a colorant, it is colored and given a design. In particular, when an acoustic vibration member is additively manufactured under conditions in which it contains two or more thermoplastic resins with different melting points, at least one of which is uncolored pellets containing no colorant and the other thermoplastic resins are colored pellets containing a colorant, the multiple thermoplastic resins do not completely mix with each other during additive manufacturing, resulting in the coexistence of colored and uncolored layers, and giving the acoustic vibration member a distinctive design (marbled appearance) that cannot be achieved by injection molding. The acoustic vibration member has a laminated structure of uncolored layers and layers colored with one or more colorants.

[0057] When additive manufacturing is performed by a material extrusion method, the manufacturing speed may be 100 mm / min to 750 mm / min. From the viewpoint of shortening the manufacturing time and from the viewpoint that a manufacturing speed that is too fast deteriorates the manufacturing quality, a manufacturing speed of 200 mm / min to 500 mm / min is preferable.

[0058] When additive manufacturing is performed by a material extrusion method, the nozzle temperature can be selected appropriately depending on the thermoplastic resin used.

[0059] When additive manufacturing is performed by a material extrusion method, the layer pitch may be 1 mm to 4 mm. "Layer pitch" refers to the thickness of one resin layer formed during modeling using a 3D printer.

[0060] When additive manufacturing is performed using the material extrusion method, it is preferable to dry the modeling material beforehand. If the modeling material is not dried, it may absorb moisture and foam, causing the surface of the model to become rough.

[0061] When additive manufacturing is performed by material extrusion, the manufacturing material used may be in pellet or filament form.

[0062] - Natural frequency and vibration mode measurement process - Next, in the natural frequency and vibration mode measuring step, the natural frequency and vibration mode of the actual acoustic vibration member that has been additively manufactured are measured.

[0063] There are no particular limitations on the method for measuring the natural frequency and vibration mode. Measurements can be performed using, for example, a commercially available microphone or a smartphone measurement app. The acoustic vibration component is placed on a material that prevents vibration transmission, such as urethane foam, and an excitation force (impact) is applied in a direction and at a location that will result in the vibration mode in the predicted process, causing the component to vibrate and undergo measurement.

[0064] -Post-processing process- Next, in the post-processing step, the acoustic vibration member is post-processed so that it has a predetermined natural frequency and vibration mode in accordance with the natural frequency and vibration mode of the acoustic vibration member measured in the natural frequency and vibration mode measurement step.

[0065] Post-processing can be performed by, for example, cutting. If the measured natural frequency of the acoustic vibration member is higher than the predetermined natural frequency of the acoustic vibration member, the thickness or height of the acoustic vibration member is reduced by cutting. By reducing the thickness or height, the rigidity of the acoustic vibration member can be reduced, thereby lowering the natural frequency. This allows the natural frequency of the acoustic vibration member to be adjusted to the predetermined natural frequency and tuned to the desired scale. On the other hand, if the measured natural frequency of the acoustic vibration member is lower than the predetermined natural frequency, it is difficult to adjust the natural frequency by cutting, so the 3D CAD model or molding conditions are adjusted to reshape the acoustic vibration member. Assuming that the natural frequency will be adjusted by post-processing, the shape may be determined from the design stage with a target frequency higher than the desired natural frequency and scale.

[0066] According to the method described above, it is possible to manufacture an acoustic vibration member made of a resin material and adjusted to a predetermined natural frequency and vibration mode.

[0067] <Acoustic vibration components> The acoustic vibration member of the present disclosure includes a thermoplastic resin, and the thermoplastic resin includes a cyclic olefin-based polymer, and the cyclic olefin-based polymer includes at least one selected from a copolymer of ethylene or an α-olefin with a cyclic olefin and a ring-opening polymer of a cyclic olefin. The acoustic vibration member of the present disclosure has a hollow portion and an opening at least at one end of the hollow portion.

[0068] With the above-described configuration, the acoustic vibration member is made of a resin material and is adjusted to a predetermined natural frequency and vibration mode, and has an excellent acoustic effect.

[0069] The details of the thermoplastic resin and the cyclic olefin polymer are as described above in the section on the production method, and therefore will not be described here.

[0070] A preferred embodiment of the acoustic vibration member is one in which the volume of the hollow portion occupies 60% or more of the volume of the acoustic vibration member, from the viewpoint of the acoustic effect in the hollow portion.

[0071] Another preferred embodiment of the acoustic vibration member is an acoustic vibration member having an opening at only one end, from the viewpoint of preventing sound buildup inside the vibration member. An opening may also be provided at the other end.

[0072] Another preferred embodiment of the acoustic vibration member, from the viewpoint of threading a string through both holes to make it into a wind chime, is an acoustic vibration member having openings at one end and the other end, with the diameter of the opening at one end being larger than the diameter of the opening at the other end.

[0073] Another preferred embodiment of the acoustic vibration member from the viewpoint of design is an acoustic vibration member having a laminated structure of an uncolored layer and a layer colored with one or more colorants.

[0074] Another preferred embodiment of the acoustic vibration member is an acoustic vibration member whose pitch is adjusted in order to have an excellent acoustic effect.

[0075] The acoustic vibration member of the present disclosure can be manufactured by the method for manufacturing an acoustic vibration member already described.

Claims

1. a step of creating three-dimensional CAD data of the acoustic vibration member on a computer, and predicting the natural frequency and vibration mode of the acoustic vibration member based on a model obtained by dividing the three-dimensional CAD data into finite elements; modifying the three-dimensional CAD data in accordance with the predicted natural frequency and vibration mode of the acoustic vibration member, and determining the shape of the acoustic vibration member; a step of additively manufacturing the acoustic vibration member based on the determined shape of the acoustic vibration member; measuring the natural frequency and vibration mode of the additively manufactured acoustic vibration member; post-processing the acoustic vibration member so that the acoustic vibration member has a predetermined natural frequency and vibration mode in accordance with the measured natural frequency and vibration mode; A method for manufacturing an acoustic vibration member, comprising:

2. The method for manufacturing an acoustic vibration member according to claim 1 , wherein the acoustic vibration member includes a thermoplastic resin.

3. 2. The method for producing an acoustic vibration member according to claim 1, wherein the acoustic vibration member contains a thermoplastic resin, the thermoplastic resin containing a cyclic olefin polymer, and the cyclic olefin polymer containing at least one selected from a copolymer of ethylene or an α-olefin with a cyclic olefin and a ring-opening polymer of a cyclic olefin.

4. An acoustic vibration member comprising a thermoplastic resin, the thermoplastic resin comprising a cyclic olefin polymer, the cyclic olefin polymer comprising at least one selected from a copolymer of ethylene or an α-olefin with a cyclic olefin, and a ring-opening polymer of a cyclic olefin, An acoustic vibration member having a hollow portion and an opening at at least one end of the hollow portion.

5. 5. The acoustic vibration member according to claim 4, wherein the volume of the hollow portion occupies 60% or more of the volume of the acoustic vibration member.

6. 5. The acoustic vibration member according to claim 4, having an opening at only one end.

7. 5. The acoustic vibration member according to claim 4, wherein the acoustic vibration member has openings at one end and the other end, the diameter of the opening at the one end being larger than the diameter of the opening at the other end.

8. 5. The acoustic vibration member according to claim 4, having a laminated structure of an uncolored layer and a layer colored with one or more colorants.

9. 5. The acoustic vibrating member according to claim 4, wherein the pitch is tuned.

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