Chip type heat-resistant acoustic sensor and manufacturing method thereof

Abstract

To provide a chip-type heat-resistant acoustic sensor for detecting a defect occurring in a molding formed by a mold, and a manufacturing method thereof.SOLUTION: In one embodiment of the present invention, a chip-type heat-resistant acoustic sensor 15 arranged on an outer surface of a mold 11 and detecting an acoustic signal, has a metal chip 13, a piezoelectric film 12, and an electrode film 21. The integrated chip-type heat-resistant acoustic sensor 15 is formed by the metal chip 13 and a laminated film obtained by laminating the piezoelectric film 12 and the electrode film 21 on one side of the metal chip 13, the other side of the metal chip 13 is in contact with the outer surface of the mold 11, and the piezoelectric film 12 supplies an acoustic signal for detection to the inside of an analyte in the mold 11 through the metal chip 13 and the mold 11, and a reflected signal of the acoustic signal is detected through the mold 11 and the metal chip 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chip-type heat-resistant acoustic sensor and a method for manufacturing the same. [Background technology]

[0002] There is a technique in which a molten material such as metal is injected into a mold and solidified in the mold to obtain a molded product having a desired shape. There is also a technique in which a heated material such as metal is inserted into a mold and processed, such as extrusion, with the mold to obtain a molded product having a desired shape. In these techniques, it is required to detect defects that occur in the molded product during processing or before the molded product is removed from the mold. For example, possible defects that occur in the molded product include molding defects in which the molten material is not filled into the mold without gaps, and defects such as voids and cracks that occur in the molded product when it is solidified in the mold.

[0003] Therefore, it is considered possible to detect defects occurring in a molded product by using an acoustic sensor to detect acoustic signals generated or scattered inside a mold when a molten metal or other material is injected into the mold with an acoustic sensor attached thereto and the material is solidified inside the mold, or when a heated metal or other material is inserted into the mold and processed, such as extrusion, with the mold. It is also considered possible to detect defects occurring in a molded product by transmitting a detection acoustic signal inside the mold and detecting an acoustic signal reflected from the molten material in the mold, the material being processed, or the molded product with the acoustic sensor. A related technology is described in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-233802 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of various aspects of the present invention is to provide a chip-type heat-resistant acoustic sensor that detects defects occurring in a molded product produced using a die, and a method for manufacturing the same. [Means for solving the problem]

[0006] Various aspects of the present invention are described below. [1] A chip-type heat-resistant acoustic sensor that is placed on the outer surface of a mold to detect acoustic signals, The chip-type heat-resistant acoustic sensor has a metal chip, a piezoelectric film, and an electrode film, an integrated chip-type heat-resistant acoustic sensor is formed by the metal chip and a laminated film having the piezoelectric film and the electrode film laminated on one surface of the metal chip, and the other surface of the metal chip is in contact with an outer surface of the mold; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film supplies a detection acoustic signal to the inside of the specimen in the mold through the metal chip and the mold, and detects the reflected signal of the acoustic signal through the mold and the metal chip.

[0007] [2] A chip-type heat-resistant acoustic sensor that is placed on the outer surface of a mold to detect acoustic signals, The chip-type heat-resistant acoustic sensor has a metal chip, a piezoelectric film, and an electrode film, an integrated chip-type heat-resistant acoustic sensor is formed by the metal chip and a laminated film having the piezoelectric film and the electrode film laminated on one surface of the metal chip, and the other surface of the metal chip is in contact with an outer surface of the mold; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film detects acoustic signals generated from or scattered within the inside of the specimen in the mold through the mold and the metal chip.

[0008] [3] A chip-type heat-resistant acoustic sensor that is placed on the outer surface of a mold to detect acoustic signals, The chip-type heat-resistant acoustic sensor includes a solid couplant, a metal chip, a piezoelectric film, and an electrode film. one surface of the solid couplant contacts an outer surface of the mold, the other surface of the solid couplant contacts one surface of the metal chip, and the piezoelectric film and the electrode film are laminated on the other surface of the metal chip to form an integrated chip-type heat-resistant acoustic sensor; The strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film supplies a detection acoustic signal to the inside of the specimen in the mold through the metal chip, the solid couplant, and the mold, and detects a reflected signal of the acoustic signal through the mold, the solid couplant, and the metal chip.

[0009] [4] A chip-type heat-resistant acoustic sensor that is arranged on the outer surface of a mold to detect acoustic signals, The chip-type heat-resistant acoustic sensor includes a solid couplant, a metal chip, a piezoelectric film, and an electrode film. one surface of the solid couplant contacts an outer surface of the mold, the other surface of the solid couplant contacts one surface of the metal chip, and the piezoelectric film and the electrode film are laminated on the other surface of the metal chip to form an integrated chip-type heat-resistant acoustic sensor; The strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film detects acoustic signals generated from or scattered within the inside of the specimen in the mold through the mold, the solid couplant, and the metal tip.

[0010] [5] In [1] or [2] above, A chip-type heat-resistant acoustic sensor, wherein the metallic chip has an acoustic impedance within ±10% of the acoustic impedance of the mold.

[0011] [6] In paragraph [3] or [4] above, A chip-type heat-resistant acoustic sensor characterized in that the solid couplant has an acoustic impedance within ±15% (preferably within 10%) of the geometric mean value of the acoustic impedance of the metal chip and the acoustic impedance of the mold.

[0012] [7] In paragraph [1] or [2] above, The chip-type heat-resistant acoustic sensor is characterized in that when the chip-type heat-resistant acoustic sensor is attached to the mold, the pressure with which the metallic chip is pressed against the mold is 10 MPa or more.

[0013] [8] In [1] or [2] above, A chip-type heat-resistant acoustic sensor, characterized in that when the chip-type heat-resistant acoustic sensor is attached to the mold, the surface roughness of the contact surface of the mold where the metal chip comes into contact with the mold has a surface roughness Sa of 0.15 μm or less.

[0014] [9] In paragraph [3] or [4] above, A chip-type heat-resistant acoustic sensor, characterized in that the outer surface of the mold and the surface of the metal chip with which the solid couplant comes into contact have a surface roughness Sa of 0.5 μm or less and a flatness of 0.02 mm or less.

[0015]

[10] In any one of paragraphs [1] to [4] above, The piezoelectric film is made of bismuth titanate (Bi 4 Ti 3 O 12 ) or lithium niobate (LiNbO 3 ). A chip-type heat-resistant acoustic sensor comprising:

[0016]

[11] In paragraph

[10] above: The chip-type heat-resistant acoustic sensor is characterized in that the piezoelectric film is a porous piezoelectric film having a density of 60% or more and 90% or less.

[0017]

[12] In any one of paragraphs [1] to [4] above: A chip-type heat-resistant acoustic sensor, wherein the thickness of the piezoelectric film is 10 μm or more and 500 μm or less.

[0018]

[13] In any one of paragraphs [1] to [4] above: A chip-type heat-resistant acoustic sensor, characterized in that wiring 22 is electrically connected to the electrode film.

[0019]

[14] In paragraph

[13] above: The electrode film is heat-resistant to 400 degrees and contains metal, making it a chip-type heat-resistant acoustic sensor.

[0020]

[15] In paragraph

[14] above: 13. A chip-type heat-resistant acoustic sensor, wherein the metal is at least one selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum.

[16] In any one of paragraphs [1] to [4] above: The chip-type heat-resistant acoustic sensor is characterized in that the size of the chip-type heat-resistant acoustic sensor is such that the outer diameter of its planar shape is 20 mm or less, and the height is 15 mm or less.

[0021]

[17] A method for manufacturing a chip-type heat-resistant acoustic sensor that is disposed on an outer surface of a mold and detects an acoustic signal, comprising: (a) preparing a metal tip; Bismuth titanate (Bi 4 Ti 3 O 12 ) or lithium niobate (LiNbO 3 ) powder was mixed with titanium dioxide (TiO 2 ) and strontium carbonate (SrCO 3 (b) forming a sol-gel solution by mixing the sol-gel precursor solution containing a mixture of (c) forming a film on the metal chip by applying the sol-gel solution onto the metal chip; (d) firing the film at a temperature of 100° C. to 650° C. to form a piezoelectric film on the metal chip; having A method for manufacturing a chip-type heat-resistant acoustic sensor, wherein the metal chip has an acoustic impedance within ±10% of the acoustic impedance of the mold.

[0022]

[18] In paragraph

[17] above: After the step (d), a step (e) is provided for forming an electrode film containing at least one metal selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum on the piezoelectric film by a sputtering method or a vapor deposition method; A method for manufacturing a chip-type heat-resistant acoustic sensor, characterized in that the thickness of the electrode film is 10 nm or more and 5 μm or less.

[0023]

[19] In paragraph

[17] above: After the step (d), a step (e') of applying a paste containing at least one metal selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum onto the piezoelectric film to form a film having a thickness of 5 μm to 100 μm; (f) forming an electrode film on the piezoelectric film by firing the film; A method for manufacturing a chip-type heat-resistant acoustic sensor, comprising:

[0024]

[20] In any one of paragraphs

[17] to

[19] above: A method for producing a chip-type heat-resistant acoustic sensor, wherein the solute concentration of the sol-gel precursor solution in the step (b) is 0.05 mol / l or more and 10 mol / l or less.

[0025]

[21] In any one of paragraphs

[17] to

[19] above: 2. A method for producing a chip-type heat-resistant acoustic sensor, wherein the mixing ratio of the powder to the sol-gel precursor solution in the step (b) is (0.5-0.9):1. Effect of the Invention

[0026] According to various aspects of the present invention, it is possible to provide a chip-type heat-resistant acoustic sensor that detects defects occurring in a molded product formed using a die, and a method for manufacturing the same. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a schematic diagram showing a state in which a chip-type heat-resistant acoustic sensor according to one embodiment of the present invention is attached to a mold. [Diagram 2] 4 is a schematic diagram showing a state in which the chip-type heat-resistant acoustic sensor 15 shown in FIG. 3 is attached to a mold. FIG. [Diagram 3] 2 is a cross-sectional view showing the chip-type heat-resistant acoustic sensor shown in FIG. 1. [Figure 4] 1 is a cross-sectional view showing a chip-type heat-resistant acoustic sensor according to one embodiment of the present invention. [Diagram 5] In Example 1, a chip-type heat-resistant acoustic sensor 15 was attached to a mold 11 using the method described in the first embodiment (see FIG. 1 ) to measure whether the reflection intensity of an acoustic signal (intensity of the reflected signal) can be detected, and the detected ultrasonic waveform (RF wave) was shown as a full-wave rectified DC wave. [Figure 6] In Example 4, a chip-type heat-resistant acoustic sensor 15 was attached to a mold 11 using the method described in the first embodiment (see FIG. 1) to detect the reflection intensity of an acoustic signal (intensity of the reflected signal) at a temperature of 400 degrees, and the result is shown in the form of an ultrasonic waveform (RF wave). [Figure 7] In Example 4, a chip-type heat-resistant acoustic sensor 15 was attached to a mold 11 using the method described in the first embodiment (see FIG. 1) to detect the reflection intensity of an acoustic signal (intensity of the reflected signal) at room temperature, and the result is shown in the form of an ultrasonic waveform (RF wave). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the form and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0029] (First embodiment) Fig. 1 is a schematic diagram showing a state in which a chip-type heat-resistant acoustic sensor according to one embodiment of the present invention is attached to a mold. Fig. 3 is a cross-sectional view showing the chip-type heat-resistant acoustic sensor shown in Fig. 1. The temperature environment in which this chip-type heat-resistant acoustic sensor can be used is, for example, an outer surface temperature of a mold 11 of 600 degrees or less.

[0030] As shown in FIG. 1, a chip-type heat-resistant acoustic sensor 15 for detecting an acoustic signal is disposed on the outer surface of a mold 11. The size of this chip-type heat-resistant acoustic sensor 15 is a planar outer diameter of 7 mm to 20 mm (e.g., 10 mm) and a height of 3 mm to 15 mm (preferably 5 mm to 10 mm). Such a small chip-type heat-resistant acoustic sensor 15 enables highly accurate measurement in a high-temperature environment. In this specification, a mold refers to a mold for manufacturing metal or resin parts for industrial products by plastic processing such as casting or press processing, injection molding, or the like. The material of the mold 11 may be steel.

[0031] 1 and 3, the chip-type heat-resistant acoustic sensor 15 has a metal chip 13, a piezoelectric film 12, and an electrode film 21. The chip-type heat-resistant acoustic sensor 15 is formed as an integrated acoustic sensor by the metal chip 13 and a laminated film in which the piezoelectric film 12 and the electrode film 21 are laminated on one surface of the metal chip 13. The other surface of the metal chip 13 contacts the outer surface of the mold 11. In other words, the piezoelectric film 12 is arranged in close contact with one surface (upper surface) of the metal chip 13, and the electrode film 21 is arranged in close contact with the upper surface of the piezoelectric film 12.

[0032] The above-mentioned piezoelectric film 12 supplies a detection acoustic signal (e.g., ultrasound) to the inside of the subject in the mold 11 through the metal chip 13 and the mold 11, and detects the reflected signal of the acoustic signal through the mold 11 and the metal chip 13.

[0033] In this embodiment, as described above, an acoustic signal for detection is supplied from the piezoelectric film 12 to the inside of the specimen in the mold 11 through the metal chip 13 and the mold 11. However, it is also possible for the piezoelectric film 12 to detect an acoustic signal generated from or scattered within the specimen in the mold 11 through the mold 11 and the metal chip 13 without supplying an acoustic signal from the piezoelectric film 12.

[0034] The metallic tip 13 preferably has an acoustic impedance within ±10% of the acoustic impedance of the mold 11. The acoustic impedance is calculated by "sound speed x density". It is preferable that the acoustic impedance of the metallic tip 13 and the acoustic impedance of the mold 11 are the same, but the above ±10% range is within the allowable range.

[0035] Furthermore, it is preferable that the material of the metal tip 13 is acoustically equivalent to the material of the mold 11, or, when a solid couplant is used, the acoustic impedance of the solid couplant is the geometric mean value of the acoustic impedances of the metal tip 13 and the mold 11. This makes it easier for the acoustic signal from the mold 11 to be transmitted to the metal tip 13, making it easier to detect with an acoustic sensor. Note that "equivalent geometric mean" means that the geometric mean values ​​are the same or within a range of ±15%.

[0036] When attaching the chip-type heat-resistant acoustic sensor 15 to the mold 11, the pressure with which the metal chip 13 is pressed against the mold 11 is preferably 10 MPa or more. By applying such a pressing pressure, it is possible to prevent air from entering between the metal chip 13 and the mold 11. As a result, it is possible to reduce reflection of the acoustic signal, making it easier for the acoustic signal to pass through the mold 11 and the metal chip 13.

[0037] The above pressing pressure is generated by the pressing force exerted by the screws or the like that fasten the mounting member 31, which attaches the periphery of the metal tip 13 to the mold 11, to the mold 11 by means of screws or the like (not shown).

[0038] Furthermore, when attaching the chip-type heat-resistant acoustic sensor 15 to the mold 11, the surface roughness of the contact surface of the mold 11 where the metal chip 13 comes into contact with the mold 11 should preferably be a surface roughness Sa of 0.15 μm or less. In this way, the surface roughness should not be rough, which can prevent air from getting between the metal chip 13 and the mold 11. As a result, the reflection of the acoustic signal can be reduced, making it easier for the acoustic signal to pass between the mold 11 and the metal chip 13.

[0039] The piezoelectric film 12 is made of bismuth titanate (Bi 4 Ti 3 O 12 ) or lithium niobate (LiNbO 3 ) The piezoelectric film 12 is preferably a porous piezoelectric film having a density of 60% to 90%. The thickness of the piezoelectric film 12 is preferably 10 μm to 500 μm. The piezoelectric film 12 is preferably heat resistant and flexible.

[0040] The electrode film 21 contains a metal that is heat resistant up to 400 degrees and has good electrical conductivity. This metal is preferably made of at least one selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum.

[0041] A wiring 22 is electrically connected to the electrode film 21. The wiring 22 is preferably a wiring with a heat-resistant protective tube. In detail, one end of the wiring 22 is connected to the upper surface of the electrode film 21 by a terminal 41, and the terminal 41 is fixed to the electrode film 21 by a fixing member 34. The fixing member 34 is composed of an attachment member 32 that is attached to the mold 11, and a leaf spring 33 attached to the attachment member 32. One end of the leaf spring 33 is attached to the upper surface of the attachment member 32 by a screw or the like, and the other end of the leaf spring 33 is arranged so as to press the terminal 41 downward (toward the electrode film 21). One end of the leaf spring 33 is fixed to the mold 11 together with the attachment member 32 by a screw or the like.

[0042] In the method of fixing the terminal 41 by the leaf spring 33 described above, it is possible to mount the chip-type heat-resistant acoustic sensor in a narrow space on the mold 11.

[0043] One end of the wiring 23 with a heat-resistant protective tube is connected to the mold 11 or the mounting member 31, and this wiring 23 with a heat-resistant protective tube is electrically connected to the underside of the piezoelectric film 12. The other end of the wiring 23 with a heat-resistant protective tube is electrically connected to the ground. In other words, the wiring 23 with a heat-resistant protective tube serves as a ground line, and the wiring 22 with a heat-resistant protective tube serves as a signal line. This wiring 22 with a heat-resistant protective tube is electrically connected to a measuring device (not shown) for measuring an acoustic signal detected by the piezoelectric film 12. This measuring device may have a function of generating a signal for the piezoelectric film 12 to generate an acoustic signal (e.g., ultrasonic wave).

[0044] According to this embodiment, the chip-type heat-resistant acoustic sensor 15 attached to the mold 11 has a metal chip 13, a piezoelectric film 12, and an electrode film 21, and the metal chip 13 and the laminated film in which the piezoelectric film 12 and the electrode film 21 are laminated on one side of the metal chip 13 form an integrated chip-type heat-resistant acoustic sensor 15. Therefore, while a material such as a molten metal is injected into the mold 11 and solidified in the mold 11 to form a molded product, an acoustic signal for detection is supplied from the piezoelectric film 12 to the inside of the mold 11 through the metal chip 13, and a reflected signal of the acoustic signal for detection supplied to the inside of the mold 11 is detected by the piezoelectric film 12, and the signal is imported to a measuring instrument through the electrode film 21 and the wiring 22. By measuring the acoustic signal with this measuring instrument, it is possible to detect defects occurring in the molded product. By attaching a plurality of chip-type heat-resistant acoustic sensors 15 to the outer surface of the mold 11, it is also possible to identify the position of a defect occurring in the molded product.

[0045] In addition, when a molten material such as metal is injected into the mold 11 and solidified in the mold 11 to form a molded product, an acoustic signal generated from the material or molded product or scattered within the material or molded product is detected by the piezoelectric film 12, and the signal is imported to a measuring instrument through the electrode film 21 and the wiring 22. By measuring the acoustic signal with this measuring instrument, it is possible to detect defects occurring in the molded product. In addition, by attaching a plurality of chip-type heat-resistant acoustic sensors 15 to the outer surface of the mold 11, it is also possible to identify the location of defects occurring in the molded product.

[0046] In addition, since the metal chip 13 is simply placed between the piezoelectric film 12 and the mold 11, the boundary surface between the piezoelectric film 12 and the mold 11 is the boundary surface between the metal chip 13 and the mold 11, and since there are few reflective surfaces, the acoustic signal for detection is reflected and transmitted at the boundary surface (the remainder of the reflected acoustic signal is transmitted), so the smaller the sound pressure reflectance at the boundary surface, the more the transmitted acoustic signal can be increased, and the easier it is for the acoustic signal for detection to be transmitted. By reducing the boundary surface in this way, the sound pressure reflectance at the boundary surface can be suppressed, and the piezoelectric film 12 can more strongly receive the acoustic signal reflected by the material or molded product in the mold 11, or the acoustic signal generated from or scattered inside the material or molded product. Therefore, it is possible to detect defects occurring in the material or molded product with higher accuracy.

[0047] Second Embodiment Fig. 4 is a cross-sectional view showing a chip-type heat-resistant acoustic sensor according to one embodiment of the present invention, in which the same parts as those in Fig. 3 are given the same reference numerals and the description of the same parts is omitted. Note that the chip-type heat-resistant acoustic sensor 15a shown in Fig. 4 is also attached to the mold 11 shown in Fig. 1 for use, similarly to the chip-type heat-resistant acoustic sensor 15 shown in Fig. 3.

[0048] A chip-type heat-resistant acoustic sensor 15a shown in FIG. 4 is arranged such that a solid couplant 14 is in contact with the lower surface of the metal chip 13 in the chip-type heat-resistant acoustic sensor 15 shown in FIG.

[0049] When the chip-type heat-resistant acoustic sensor 15a shown in Fig. 4 is attached to the mold 11, the configuration is the same as that shown in Fig. 1, except that the solid couplant 14 is placed between the metal tip 13 and the mold 11. In other words, one side of the solid couplant 14 contacts the metal tip 13, and the other side of the solid couplant 14 contacts the outer surface of the mold 11. The solid couplant 14 is installed as an acoustic coupling between the metal tip 13 and the mold 11. The planar shape of the solid couplant 14 may be the same as that of the metal tip 13, or the solid couplant 14 may be smaller than the metal tip 13.

[0050] The solid couplant 14 should have an acoustic impedance within ±15% of the geometric mean value of the acoustic impedance of the metal tip 13 and the acoustic impedance of the mold 11, and preferably within 10%. This can improve the propagation characteristics of the acoustic signal. The reason why it is preferable to have an acoustic impedance within ±15% is based on the results shown in Table 2 of Example 3 described later.

[0051] The outer surface of the mold 11 and the surface of the metallic tip 13 with which the solid couplant 14 comes into contact should preferably have a surface roughness Sa of 0.5 μm or less and a flatness of 0.02 mm or less. This allows the metallic tip 13 and the solid couplant 14 to be in close contact with the outer surface of the mold 11. As a result, air is less likely to get in between the mold 11 and the solid couplant 14, between the solid couplant 14 and the metallic tip 13, and between the metallic tip 13 and the piezoelectric film 12. Flatness is a numerical value that indicates the degree of flatness (uniformity) of a surface, and indicates how much of a gap is allowable when the surface to be measured is sandwiched between two parallel planes.

[0052] Also, it is preferable that the strength or hardness of the solid couplant 14 is equal to or less than the strength or hardness of the metal tip 13. This makes the solid couplant 14 more easily deformable, and increases the degree of adhesion between the metal tip 13, the solid couplant 14, and the mold 11, thereby preventing air from entering between the mold 11, the solid couplant 14, and the metal tip 13. As a result, it is possible to reduce the reflection of acoustic signals, and to facilitate the passage of acoustic signals between the solid couplant 14 and the metal tip 13. The high degree of adhesion is achieved by the overall plastic deformation of the solid couplant 14 and local flow to the uneven parts of the outer surface of the mold 11.

[0053] According to this embodiment, a material such as a molten metal is injected into the mold 11, and while the material is solidified in the mold 11 to form a molded product, an acoustic signal for detection (e.g., ultrasonic wave) is supplied from the piezoelectric film 12 through the metallic tip 13, the solid couplant 14, and the mold 11 to the inside of the material in the mold 11 or the molded product, and a reflected signal of the acoustic signal is detected through the mold 11, the solid couplant 14, and the metallic tip 13. The detected signal is imported into a measuring instrument through the wiring 22. By measuring the acoustic signal with this measuring instrument, it becomes possible to detect defects occurring in the molded product.

[0054] In addition, while a molten material such as metal is injected into the mold 11 and solidified within the mold 11 to form a molded product, an acoustic signal generated from the material or molded product or scattered within it is detected by the piezoelectric film 12, and the signal is imported to a measuring instrument through wiring 22. By measuring the acoustic signal with this measuring instrument, it becomes possible to detect defects occurring in the molded product.

[0055] (Third embodiment) FIG. 2 is a schematic diagram showing a state in which the chip-type heat-resistant acoustic sensor 15 shown in FIG. 3 is attached to a mold. The same parts as those in FIG. 1 are given the same reference numerals, and the description of the same parts will be omitted.

[0056] The chip-type heat-resistant acoustic sensor 15 is attached to the mold 11 by the attachment member 31, and the terminal 41 is pressed downward by the coil spring 35. In detail, one side of the coil spring 35 is fixed to the plate-like member 36, and the other side of the coil spring 35 fixed to this plate-like member 36 presses the terminal 41, and in this state, the plate-like member 36 is fixed to the attachment member 31 by screws 37 and 38. In this manner, the chip-type heat-resistant acoustic sensor 15 is attached to the mold 11.

[0057] In this embodiment, the same effects as in the first embodiment can be obtained.

[0058] In this embodiment, the chip-type heat-resistant acoustic sensor 15 shown in FIG. 3 is used, but it is also possible to use a chip-type heat-resistant acoustic sensor 15a shown in FIG.

[0059] (Fourth embodiment) A method for manufacturing a heat-resistant chip-type acoustic sensor according to one embodiment of the present invention will be described with reference to FIG.

[0060] First, a metal tip 13 is prepared (step (a)). This metal tip 13 should have an acoustic impedance within ±10% of the acoustic impedance of the mold 11 shown in FIG.

[0061] Next, bismuth titanate (Bi 4 Ti 3 O 12 ) or lithium niobate (LiNbO 3 ) powder was mixed with titanium dioxide (TiO 2 ) and strontium carbonate (SrCO 3 ) into a sol-gel precursor solution containing the mixture to form a sol-gel solution (step (b)).

[0062] The solute concentration of the sol-gel precursor solution is preferably 0.05 mol / l or more and 10 mol / l or less, and the mixing ratio of the powder to the sol-gel precursor solution is preferably (0.5-0.9):1.

[0063] Thereafter, the sol-gel solution is applied onto the metal chip 13 to form a film on the metal chip 13 (step (c)). Next, this film is fired at a temperature of 100° C. or more and 650° C. or less to form the piezoelectric film 12 on the metal chip 13 (step (d)).

[0064] Thereafter, an electrode film 21 containing at least one metal selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum is formed on the piezoelectric film 12 by sputtering or vapor deposition (step (e)). The thickness of the electrode film 21 is preferably 10 nm or more and 5 μm or less.

[0065] In this embodiment, the electrode film 21 is formed by sputtering or vapor deposition, but the present invention is not limited to this and may be modified as follows. A paste containing at least one metal selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum is applied onto the piezoelectric film 12 to form a film having a thickness of 5 μm to 100 μm (step (e')).Then, the film is fired to form an electrode film 21 on the piezoelectric film 12 (step (f)). EXAMPLES

[0066] In Example 1, a chip-type heat-resistant acoustic sensor 15 was attached to a mold 11 using the method described in the first embodiment (see Fig. 1), and measurements were made at room temperature to see whether the reflection intensity of an acoustic signal (intensity of the reflected signal) could be detected. The results of the measurements are shown in Fig. 5. The measurement method used here was to supply an acoustic signal for detection inside the mold 11 using a piezoelectric film 12, and detect the reflected signal of the acoustic signal using the chip-type heat-resistant acoustic sensor 15.

[0067] The material of the metal tip 13 was steel, and the material of the die 11 was also steel. The piezoelectric film 12 and the electrode film 21 were made by the method described in the fourth embodiment. The outer surface (contact surface) of the mold 11 where the metal tip 13 and the mold 11 come into contact, and the back surface of the metal tip 13 (contact surface with the mold 11) were each polished, and their surface roughness was measured. The measurement results are shown in "Surface Roughness" in FIG. 5. In the "Surface Roughness" shown in FIG. 5, the numerical values ​​of "coarse", "medium", and "fine" are the measurement results of the outer surface (contact surface) of the mold 11 and the back surface of the metal tip 13, respectively, and chip-type heat-resistant acoustic sensors 15 with the surface roughnesses of "coarse", "medium", and "fine" for both were prepared, and the reflected signals of the acoustic signals described above were measured by these chip-type heat-resistant acoustic sensors 15. The measurement results are shown in FIG. 5.

[0068] When the measurement result of the reflection intensity shown in FIG. 5 is "◯," it means that the acoustic signal reflected from inside the mold was detected. When the measurement result of the reflection intensity is "×," it means that the acoustic signal due to multiple reflections inside the metal chip was detected, but the reflection intensity could not be detected accurately.

[0069] 5, the surface roughness (surface roughness of the contact surface of the metal tip 13 with the mold 11) was measured by a non-contact roughness measuring method. Sq is the root mean square height, and Sa is the arithmetic mean height value.

[0070] As shown in Figure 5, the chip-type heat-resistant acoustic sensor 15, which has a mirror-finished contact surface between the metal chip 13 and the mold 11, was able to detect the acoustic signal reflected from inside the mold. This is believed to be because the air layer at the interface was eliminated by polishing the back surface of the metal chip 13 and the outer surface (contact surface) of the mold 11, and the acoustic impedance of the material that constitutes the interface matched. EXAMPLES

[0071] In Example 2, the chip-type heat-resistant acoustic sensor 15 without a solid couplant described in the first embodiment (see FIG. 1) and the chip-type heat-resistant acoustic sensor 15a with a solid couplant described in the second embodiment (see FIG. 4) were attached to a mold 11, and measurements were made at room temperature to see whether the reflection intensity of an acoustic signal (intensity of a reflected signal) could be detected. The results of the measurements are shown in Table 1. The measurement method used here was the same as in Example 1. That is, Table 1 shows the effect of the solid couplant in the chip-type heat-resistant acoustic sensor and the effect of the surface roughness of the metal chip 13.

[0072] In Table 1, "film thickness (μm)" is the thickness of the piezoelectric film 12, "contact surface finish" is the surface roughness of the back surface of the metal chip 13 (contact surface with the mold 11), and the plate thickness of the solid couplant 14 was 0.4 mm. The measurement results "◯" and "×" have the same meanings as in Example 1. In addition, the outer surface (contact surface) of the mold 11 was polished, and the surface roughness of the outer surface of the mold 11 was Sq 0.107 μm and Sa 0.076 μm.

[0073] The materials of the metal tip 13 and the die are the same as those in the first embodiment. The piezoelectric film 12 and the electrode film 21 were made by the method described in the fourth embodiment. The material of the solid couplant 14 is zinc.

[0074] [Table 1]

[0075] According to Table 1, if the contact surface is unfinished and the surface roughness of the contact surface of the metal tip 13 is rough, a solid couplant is required, but if the contact surface is finished, the measurement result was ``good'' regardless of whether a solid couplant was used or not. EXAMPLES

[0076] In Example 3, the chip-type heat-resistant acoustic sensor 15 without a solid couplant described in the first embodiment (see FIG. 1) and the chip-type heat-resistant acoustic sensor 15a with a solid couplant described in the second embodiment (see FIG. 4) were attached to the mold 11, and whether or not the reflection intensity of the acoustic signal (intensity of the reflected signal) could be detected was measured at room temperature. In this example, a chip-type heat-resistant acoustic sensor 15a was prepared in which the combination of the material of the metal chip 13 ("chip material" shown in Table 2) and the material of the solid couplant 14 ("solid couplant" shown in Table 2) was changed. The measurement results are shown in Table 2. The measurement method here is the same as in Example 1. That is, Table 2 shows the influence of the relationship between the material of the metal chip 13 and the material of the solid couplant 14 in the chip-type heat-resistant acoustic sensor.

[0077] In this embodiment, a solid couplant 14 with a plate thickness of 0.4 mm was used. The "◯" and "X" in the measurement results shown in Table 2 have the same meanings as in Example 1. The surface roughness of the back surface (contact surface) of the metal tip 13 is approximately that of a lathe finish, with specific surface roughnesses of Sq of 0.639 μm and Sa of 0.493 μm (see "*" in Table 2), which correspond to no finishing shown in Table 1. The roughness of the outer surface of the mold 11 is Sq of 0.107 μm and Sa of 0.076 μm.

[0078] The material of the mold 11 is steel. The piezoelectric film 12 and the electrode film 21 were made by the method described in the fourth embodiment.

[0079] [Table 2] EXAMPLES

[0080] In Example 4, a chip-type heat-resistant acoustic sensor 15 was attached to a mold 11 using the method described in the first embodiment (see FIG. 1), and measurements were made at temperatures of 400° C. and room temperature to see whether the reflection intensity of an acoustic signal (intensity of the reflected signal) could be detected. The measurement results at 400° C. are shown in FIG. 6, and the measurement results at room temperature are shown in FIG. 7. The measurement method used here was a method in which an acoustic signal for detection was supplied to the inside of the mold 11 by the piezoelectric film 12, and the reflected signal of the acoustic signal was detected by the chip-type heat-resistant acoustic sensor 15.

[0081] The material of the metal tip 13 was steel, and the material of the die 11 was also steel. The piezoelectric film 12 and the electrode film 21 were made by the method described in the fourth embodiment. The outer surface (contact surface) of the mold 11 where the metal chip 13 and the mold 11 come into contact and the back surface (contact surface with the mold 11) of the metal chip 13 were each polished, and the polished mold 11 and metal chip 13 were used.

[0082] As shown in Figures 6 and 7, acoustic signals reflected from inside the mold could be detected at both 400 degrees and room temperature. It can be seen that the measurement results at a temperature of 400 degrees shown in Figure 6 show that the reflection from the back surface of the metal chip is smaller and the ratio of transmitted waves is larger than the measurement results at room temperature shown in Figure 7. The reason for this is thought to be that at a temperature of 400 degrees, the pressure pressing the metal chip 13 against the mold 11 increases due to thermal expansion of the metal chip 13 and the mold 11. [Explanation of symbols]

[0083] 11 Mold 12 Piezoelectric film 13 Metal Tip 14 Solid Couplant 15, 15a Chip-type heat-resistant acoustic sensor 21 Electrode membrane

Claims

1. A chip-type heat-resistant acoustic sensor that is disposed on the outer surface of a mold and detects an acoustic signal, The chip-type heat-resistant acoustic sensor has a metal chip, a piezoelectric film, and an electrode film, an integrated chip-type heat-resistant acoustic sensor is formed by the metal chip and a laminated film having the piezoelectric film and the electrode film laminated on one surface of the metal chip, and the other surface of the metal chip is in contact with an outer surface of the mold; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film supplies a detection acoustic signal to the inside of the specimen in the mold through the metal chip and the mold, and detects the reflected signal of the acoustic signal through the mold and the metal chip.

2. A chip-type heat-resistant acoustic sensor that is disposed on the outer surface of a mold and detects an acoustic signal, The chip-type heat-resistant acoustic sensor has a metal chip, a piezoelectric film, and an electrode film, an integrated chip-type heat-resistant acoustic sensor is formed by the metal chip and a laminated film having the piezoelectric film and the electrode film laminated on one surface of the metal chip, and the other surface of the metal chip is in contact with an outer surface of the mold; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film detects acoustic signals generated from or scattered within the inside of the specimen in the mold through the mold and the metal chip.

3. A chip-type heat-resistant acoustic sensor that is disposed on the outer surface of a mold and detects an acoustic signal, The chip-type heat-resistant acoustic sensor includes a solid couplant, a metal chip, a piezoelectric film, and an electrode film. one surface of the solid couplant contacts an outer surface of the mold, the other surface of the solid couplant contacts one surface of the metal chip, and the piezoelectric film and the electrode film are laminated on the other surface of the metal chip to form an integrated chip-type heat-resistant acoustic sensor; The strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film supplies a detection acoustic signal to the inside of a specimen in the mold through the metal tip, the solid couplant, and the mold, and detects a reflected signal of the acoustic signal through the mold, the solid couplant, and the metal tip.

4. A chip-type heat-resistant acoustic sensor that is disposed on the outer surface of a mold and detects an acoustic signal, The chip-type heat-resistant acoustic sensor includes a solid couplant, a metal chip, a piezoelectric film, and an electrode film. one surface of the solid couplant contacts an outer surface of the mold, the other surface of the solid couplant contacts one surface of the metal chip, and the piezoelectric film and the electrode film are laminated on the other surface of the metal chip to form an integrated chip-type heat-resistant acoustic sensor; The strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip; A chip-type heat-resistant acoustic sensor characterized in that the piezoelectric film detects acoustic signals generated from or scattered within the inside of the specimen in the mold through the mold, the solid couplant, and the metal tip.

5. In claim 1 or 2, A chip-type heat-resistant acoustic sensor, wherein the metallic chip has an acoustic impedance within ±10% of the acoustic impedance of the mold.

6. In claim 3 or 4, 13. A chip-type heat-resistant acoustic sensor, comprising: a solid couplant having an acoustic impedance within ±15% of the geometric mean value of the acoustic impedance of the metallic chip and the acoustic impedance of the mold.

7. In claim 1 or 2, 2. A chip-type heat-resistant acoustic sensor, wherein when the chip-type heat-resistant acoustic sensor is attached to the mold, the pressure with which the metallic chip is pressed against the mold is 10 MPa or more.

8. In claim 1 or 2, A chip-type heat-resistant acoustic sensor, characterized in that when the chip-type heat-resistant acoustic sensor is attached to the mold, the surface roughness of the contact surface of the mold where the metal chip comes into contact with the mold has a surface roughness Sa of 0.15 μm or less.

9. In claim 3 or 4, A chip-type heat-resistant acoustic sensor, characterized in that the outer surface of the mold and the surface of the metallic chip with which the solid couplant comes into contact have a surface roughness Sa of 0.5 μm or less and a flatness of 0.02 mm or less.

10. In any one of claims 1 to 4, The piezoelectric film is made of bismuth titanate (Bi ４ Ti ３ O １２ ) or lithium niobate (LiNbO ３ ) A chip-type heat-resistant acoustic sensor comprising:

11. In claim 10, A chip-type heat-resistant acoustic sensor, wherein the piezoelectric film is a porous piezoelectric film having a density of 60% or more and 90% or less.

12. In any one of claims 1 to 4, A chip-type heat-resistant acoustic sensor, wherein the thickness of the piezoelectric film is 10 μm or more and 500 μm or less.

13. In any one of claims 1 to 4, A chip-type heat-resistant acoustic sensor, characterized in that wiring 22 is electrically connected to the electrode film.

14. In claim 13, The electrode film is heat-resistant to 400 degrees and contains a metal.

15. In claim 14, 13. A chip-type heat-resistant acoustic sensor, wherein the metal is at least one selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum.

16. In any one of claims 1 to 4, The chip-type heat-resistant acoustic sensor is characterized in that the size of the chip-type heat-resistant acoustic sensor is such that the outer diameter of its planar shape is 20 mm or less and the height is 15 mm or less.

17. A method for manufacturing a chip-type heat-resistant acoustic sensor that is disposed on an outer surface of a mold and detects an acoustic signal, comprising the steps of: (a) preparing a metal tip; Bismuth titanate (Bi ４ Ti ３ O １２ ) or lithium niobate (LiNbO ３ ) powder, titanium oxide (TiO ２ ) and strontium carbonate (SrCO ３ (b) forming a sol-gel solution by mixing the sol-gel precursor solution containing a mixture of (c) forming a film on the metal chip by applying the sol-gel solution onto the metal chip; (d) forming a piezoelectric film on the metal chip by firing the film at a temperature of 100° C. or more and 650° C. or less; having The method for manufacturing a chip-type heat-resistant acoustic sensor is characterized in that the metallic chip has an acoustic impedance within ±10% of the acoustic impedance of the mold.

18. In claim 17, and after the step (d), a step (e) of forming an electrode film containing at least one metal selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum on the piezoelectric film by a sputtering method or a vapor deposition method, The method for manufacturing a chip-type heat-resistant acoustic sensor is characterized in that the thickness of the electrode film is 10 nm or more and 5 μm or less.

19. In claim 17, After the step (d), a step (e') of applying a paste containing at least one metal selected from the group consisting of gold, silver, platinum, nickel, titanium, and aluminum onto the piezoelectric film to form a film having a thickness of 5 μm to 100 μm; (f) forming an electrode film on the piezoelectric film by firing the film; A method for manufacturing a chip-type heat-resistant acoustic sensor, comprising:

20. In any one of claims 17 to 19, A method for producing a chip-type heat-resistant acoustic sensor, wherein the solute concentration of the sol-gel precursor solution in the step (b) is 0.05 mol / L or more and 10 mol / L or less.

21. In any one of claims 17 to 19, A method for manufacturing a chip-type heat-resistant acoustic sensor, wherein the mixing ratio of the powder to the sol-gel precursor solution in the step (b) is (0.5-0.9):1.

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