Acoustic sensor attachment member and acoustic sensor attachment method

Abstract

To provide an attachment member for attaching an acoustic sensor to an outer surface of a mold to detect a defect occurring in a molded product formed by the mold.SOLUTION: An aspect of the present invention is an acoustic sensor attachment member 15 that attaches an acoustic sensor 12 to a mold 11. The attachment member 15 has a metal chip 13 and a solid couplant 14. The metal chip 13 is in contact with the acoustic sensor 12. One face of the solid couplant 14 is in contact with the metal chip 13. The other face of the solid couplant 14 is in contact with an outer surface of the mold 11. The acoustic sensor 12 is a sensor that detects an acoustic signal generated from the inside of or scattered inside an analyte in the mold 11. The metal chip 13 has an acoustic impedance within ±15% of the acoustic impedance of the mold 11. The proof stress or hardness of the solid couplant 14 is equal to or less than the proof stress or hardness of the metal chip 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mounting member for an acoustic sensor and a method for mounting an acoustic sensor. [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 occurring in the molded product during processing or before the molded product is removed from the mold. For example, possible defects occurring in the molded product include whether the molten material is filled into the mold without gaps, and defects such as voids and cracks occurring 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] Various aspects of the present invention have an objective of providing an acoustic sensor mounting member and an acoustic sensor mounting method for mounting an acoustic sensor on the outer surface of a mold in order to detect defects that occur in a molded product molded with the mold. [Means for solving the problem]

[0006] Various aspects of the present invention are described below. [1] An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, comprising: The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip.

[0007] [2] An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor, the acoustic sensor being mounted on the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip.

[0008] [3] In [1] or [2] above, the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is less than the strength or hardness of the metal tip.

[0009] [4] An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is less than the strength or hardness of the metal tip.

[0010] [5] An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is less than the strength or hardness of the metal tip.

[0011] [6] In any one of paragraphs [1], [2], [4] and [5] above, A mounting member for an acoustic sensor, characterized in that the force tightening the metal tip to the die is 1.1 times or more the product of the contact area between the die or the metal tip and the solid couplant and the yield strength of the solid couplant.

[0012] [7] In any one of paragraphs [1], [2], [4] and [5] above, The mounting member for an acoustic sensor, wherein the material of the solid couplant has a sound pressure reflectance of 0.5 or less (preferably 0.4 or less).

[0013] [8] In any one of paragraphs [1], [2], [4] and [5] above, The solid couplant has a Vickers hardness of 15 or more and less than 100.

[0014] [9] In any one of paragraphs [1], [2], [4] and [5] above, An acoustic sensor mounting member, 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], [2], [4] and [5] above, A mounting member for an acoustic sensor, characterized in that when the temperature during molding using the mold is 100°C or higher, the mounting member has a function of cooling the acoustic sensor side of the metal chip.

[0016]

[11] In any one of paragraphs [1], [2], [4] and [5] above, 13. A mounting member for an acoustic sensor, wherein the metal tip has a function of pressing the solid couplant against the mold with a pressure of 20 MPa or more.

[0017]

[12] In any one of paragraphs [1], [2], [4] and [5] above, An acoustic sensor mounting member, characterized in that the mold is made of steel.

[0018]

[13] A method for attaching an acoustic sensor to an outer surface of a mold using an attachment member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 11. A method for mounting an acoustic sensor, comprising the steps of: (a) providing a solid couplant with a resistance or hardness equal to or less than that of the metal tip;

[0019]

[14] A method for attaching an acoustic sensor to an outer surface of a mold using an attachment member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 11. A method for mounting an acoustic sensor, comprising the steps of: (a) providing a solid couplant with a resistance or hardness equal to or less than that of the metal tip;

[0020]

[15] In paragraph

[13] or

[14] above, the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 11. A method for mounting an acoustic sensor, comprising the steps of: providing a solid couplant having a strength or hardness that is less than a strength or hardness of the metal tip;

[0021]

[16] A method for attaching an acoustic sensor to an outer surface of a mold using an attachment member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 11. A method for mounting an acoustic sensor, comprising the steps of: providing a solid couplant having a strength or hardness that is less than a strength or hardness of the metal tip;

[0022]

[17] A method for attaching an acoustic sensor to an outer surface of a mold using an attachment member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 11. A method for mounting an acoustic sensor, comprising the steps of: providing a solid couplant having a strength or hardness that is less than a strength or hardness of the metal tip; Effect of the Invention

[0023] According to various aspects of the present invention, a mounting member for mounting an acoustic sensor on the outer surface of a mold and a method for mounting the acoustic sensor can be provided in order to detect defects that occur in a molded product molded with the mold. [Brief description of the drawings]

[0024] [Figure 1] 1A and 1B are schematic diagrams illustrating a mounting member for an acoustic sensor according to an embodiment of the present invention. [Diagram 2]This is data showing an example of the case where the reflection intensity shown in Table 1 and FIG. 5 is "◯". [Diagram 3] This is data showing an example in which the reflection intensity shown in Table 1 and FIG. 5 is "x". [Figure 4] This is data showing an example of the reflection intensity shown in Table 1 and FIG. 5 as "Δ". [Diagram 5] These are the measurement results when the force clamping the metal tip 13 to the mold 11 satisfies the condition that it is 1.1 times or more the product of the contact area between the mold 11 or the metal tip 13 and the solid couplant 14 and the yield strength of the solid couplant 14. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] 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.

[0026] FIG. 1 is a schematic diagram for explaining a mounting member for an acoustic sensor according to one embodiment of the present invention. An acoustic sensor 12 is attached to the outer surface of the mold 11 by an attachment member 15 for the acoustic sensor. In other words, the attachment member 15 is disposed between the outer surface of the mold 11 and the acoustic sensor 12. In this specification, the 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.

[0027] The mounting member 15 has a metallic tip 13 and a solid couplant 14. The metallic tip 13 is in contact with the acoustic sensor 12. One side of the solid couplant 14 is in contact with the metallic tip 13, and the other side of the solid couplant 14 is in contact with the outer surface of the mold 11. That is, the lower surface of the solid couplant 14 is in contact with the outer surface of the mold 11, the lower surface of the metallic tip 13 is in contact with the upper surface of the solid couplant 14, and the upper surface of the metallic tip 13 is in contact with the acoustic sensor. The solid couplant 14 is a couplant installed as an acoustic coupling between the metallic tip 13 and the mold 11. The planar shape of the solid couplant 14 may be the same as that of the metallic tip 13, or the solid couplant 14 may be smaller than the metallic tip 13.

[0028] The acoustic sensor 12 may be a sensor that detects an acoustic signal generated from or scattered inside a test object (not shown) in the mold 11, or a sensor that supplies an acoustic signal for detection (e.g., ultrasonic wave) to the inside of the test object in the mold 11 and detects a reflected signal of the acoustic signal. The metallic tip 13 has an acoustic impedance within ±15% of the acoustic impedance of the mold 11, and the strength or hardness of the solid couplant 14 is preferably equal to or less than the strength or hardness of the metallic tip 13. The acoustic impedance is calculated by "sound speed x density".

[0029] The mounting member 15 may have the following various configurations. The solid couplant 14 preferably has a thickness of 1.5 times or less than the wavelength of the acoustic signal propagating within the solid couplant 14, and the strength or hardness of the solid couplant 14 preferably is less than the strength or hardness of the metal tip 13.

[0030] In addition, it is preferable that the metallic tip 13 has an acoustic impedance of more than ±15% of the acoustic impedance of the mold 11, the solid couplant 14 has an acoustic impedance within ±15% of the geometric mean value of the acoustic impedance of the metallic tip 13 and the acoustic impedance of the mold 11, and the solid couplant 14 has a thickness of 1.5 times or less the wavelength of the acoustic signal propagating through the solid couplant 14. It is preferable that the strength or hardness of the solid couplant 14 is less than the strength or hardness of the metallic tip 13.

[0031] The combination of the acoustic properties of the metal tip 13 and solid couplant 14 as described above can improve the propagation characteristics of the acoustic signal.

[0032] As described above, by making the thickness of the solid couplant 14 equal to or less than 1.5 times the wavelength of the acoustic signal propagating through the solid couplant 14, the acoustic signal can easily pass through the solid couplant 14.

[0033] In this embodiment, when using a sensor that supplies an acoustic signal for detection to the inside of the mold 11 and detects the reflected signal of the acoustic signal as described above, it is preferable to provide a mechanism for supplying the acoustic signal for detection to the inside of the mold 11 through the metal tip 13 and the solid couplant 14 together with the acoustic sensor 12.

[0034] When the acoustic sensor 12 is attached to the outer surface of the mold 11 by the attachment member 15, the force for fastening the metal tip 13 to the mold 11 is preferably 1.1 times or more the product of the contact area between the mold 11 or the metal tip 13 and the solid couplant 14 and the yield strength of the solid couplant 14. This increases the degree of adhesion between the metal tip 13, the solid couplant 14, and the mold 11, and prevents air from entering between the solid couplant 14 and the outer surface of the mold 11 and between the solid couplant 14 and the metal tip 13. As a result, the reflection of the acoustic signal can be reduced, and the acoustic signal can be easily transmitted between the solid couplant 14 and the metal tip 13. Since the force is 1.1 times or more the product of the contact area and the yield strength of the solid couplant 14, if the yield strength is constant, the smaller the contact area, the smaller the fastening force can be. Therefore, the shape (outer diameter) of the solid couplant 14 is also an important factor.

[0035] Furthermore, as described above, by setting the yield strength or hardness of the solid couplant 14 to be equal to or less than the yield strength or hardness of the metal tip 13, the solid couplant 14 becomes more easily deformed, and the degree of adhesion between the metal tip 13, the solid couplant 14, and the mold 11 can be increased, and the infiltration of air between the mold 11, the solid couplant 14, and the metal tip 13 can be suppressed. As a result, the reflection of the acoustic signal can be reduced, and the acoustic signal can be more easily transmitted between the solid couplant 14 and the metal tip 13. The high degree of adhesion is realized 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.

[0036] As shown in FIG. 1, the acoustic sensor 12 is connected via a wiring 16 to a measuring instrument 17 that measures an acoustic signal.

[0037] Moreover, the material of solid couplant 14 should have a sound pressure reflectance of 0.5 or less (preferably 0.4 or less).

[0038] Moreover, it is preferable that the solid couplant 14 has a Vickers hardness of 15 or more and less than 100. The reason for setting the upper limit hardness to less than 100 is that by making it smaller than the hardness of the mold material, which is about 400 to 500, it is possible to increase adhesion without deforming the mold.

[0039] 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 mounting member 15 having 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, it is possible to make it difficult for air to enter 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 acoustic sensor 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.

[0040] The material of the metal tip 13 is preferably acoustically equivalent to the material of the mold 11, or a material whose geometric mean of acoustic impedance with the mold 11 is equivalent to the acoustic impedance of the solid couplant 14. This makes it easier for the acoustic signal from the mold 11 to be transmitted to the metal tip 13, and easier to detect with an acoustic sensor. Note that "equivalent geometric mean" means that the geometric mean value is the same or within a range of ±15%.

[0041] Furthermore, if the temperature during molding using the die 11 is 100°C or higher, it is preferable to have a function for cooling the outer periphery of the metallic tip 13 on the acoustic sensor side. This cooling function may be, for example, a function for water-cooling the metallic tip 13. In detail, by providing a path 13a for supplying cooling water to the outer periphery of the metallic tip 13 and flowing the cooling water through the path 13a, it is possible to maintain the metallic tip 13 at a predetermined temperature or lower. This allows the use of an inexpensive general-purpose sensor that is not designed for high temperatures.

[0042] In addition, the metal tip 13 may have a function of pressing the solid couplant 14 against the die 11 with a pressure of 20 MPa or more. One example of this function is a means for placing the solid couplant 14 between the metal tip 13 and the die 11, and fastening the metal tip 13 to the die 11 with a fastening bolt to press the solid couplant 14 against the die 11. This allows the attachment member 15 having the metal tip 13 and the solid couplant 14 to be tightly attached to the outer surface of the die 11. In addition, when there is a difference in thermal expansion coefficient between the metal tip 13, the solid couplant 14, and the die 11, and the temperature during molding using the die 11 is 100°C or higher, even if these three expand thermally, the attachment member 15 having the metal tip 13 and the solid couplant 14 can be securely attached to the outer surface of the die 11. As a result, it is possible to make it difficult for air to enter between the die 11 and the solid couplant 14, and between the metal tip 13 and the solid couplant 14. The material of the die 11 is preferably steel.

[0043] Next, a method for attaching the acoustic sensor 12 to the outer surface of the mold 11 will be described. In a method for mounting an acoustic sensor 12 on the outer surface of a mold 11 by a mounting member 15, the mounting member 15 having a metal tip 13 in contact with a solid couplant 14 is disposed between the outer surface of the mold 11 and the acoustic sensor 12, and the solid couplant 14 and the metal tip 13 are mounted in a state of being pressed against the mold 11 with a pressure of 20 MPa or more. The metal tip 13 is in contact with the acoustic sensor 12. That is, the upper surface of the metal tip 13 is mounted in contact with the acoustic sensor 12, and both surfaces of the solid couplant 14 are mounted in contact with the metal tip 13 and the mold 11. In this case, it is preferable to fix the metal tip 13 and the mold 11 with a tightening bolt in a state where the solid couplant 14 is disposed between the metal tip 13 and the mold 11. In this way, it is preferable that the metal tip 13 is pressed against the mold 11 via the solid couplant 14 with a pressure of 20 MPa or more. The acoustic sensor 12 is a sensor that detects an acoustic signal generated from or scattered within the inside of the specimen in the mold 11. The metallic tip 13 preferably has an acoustic impedance within ±15% of the acoustic impedance of the mold 11. The strength or hardness of the solid couplant 14 is preferably equal to or less than the strength or hardness of the metallic tip 13.

[0044] Furthermore, the acoustic sensor 12, the metal tip 13 and the solid couplant 14 may be of any of the various configurations described above.

[0045] After the acoustic sensor 12 is attached to the mold 11 as described above, when the acoustic sensor 12 detects an acoustic signal generated or scattered from inside the specimen in the mold 11, it is preferable that the metallic tip 13 is pressed against the mold 11 via the solid couplant 14 at a pressure of 20 MPa or more. This may be achieved by pressing the metallic tip 13 and the mold 11 together with a fastening bolt as described above, but may also be achieved by other methods. Other methods include, for example, a mechanical restraint method, a hydraulic restraint, and an adhesive type, and mechanical restraint methods include a screw type, a band type, a spring type, and the like.

[0046] After the acoustic sensor 12 is attached to the mold 11 as described above, when an acoustic signal for detection is supplied to the inside of the mold 11 and the reflected signal of the acoustic signal is detected by the acoustic sensor 12, it is preferable that the metal tip 13 is pressed against the mold 11 via the solid couplant 14 with a pressure of 20 MPa or more. This method is preferably the same as the above method.

[0047] According to this embodiment, the acoustic sensor 12 is attached to the mold 11 by the attachment member 15. That is, the lower surface of the solid couplant 14 is in contact with the outer surface of the mold 11, the lower surface of the metal tip 13 is in contact with the upper surface of the solid couplant 14, and the acoustic sensor 12 is in contact with the upper surface of the metal tip 13. Therefore, while a material such as a molten metal is poured 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 inside the material or molded product is detected by the acoustic sensor 12, and the signal is imported to the measuring instrument 17 through the wiring 16. By measuring the acoustic signal with this measuring instrument 17, it is possible to detect defects occurring in the molded product. By attaching a plurality of acoustic sensors 12 to the outer surface of the mold 11, it is also possible to identify the position of a defect occurring in the molded product.

[0048] Also, an acoustic signal for detection is supplied to the inside of the mold 11 by the acoustic sensor 12 through the metal tip 13 and the solid couplant 14, a reflected signal of the acoustic signal for detection supplied to the inside of the mold 11 is detected by the acoustic sensor 12, and the signal is imported to the measuring instrument 17 through the wiring 16. By measuring the reflected signal with this measuring instrument 17, it is possible to detect defects occurring in the molded product in the mold 11. As in the case of detecting acoustic signals generated from the above-mentioned material or molded product or scattered inside the same, it is also possible to identify the location of defects occurring in the molded product by attaching a plurality of acoustic sensors 12 to the outer surface of the mold 11.

[0049] In addition, since the metallic chip 13 and the solid couplant 14 are simply disposed between the acoustic sensor 12 and the mold 11, the boundary surface between the acoustic sensor 12 and the mold 11 is the boundary surface between the metallic chip 13 and the solid couplant 14, and the solid couplant 14 and the mold 11, and the sound pressure reflectance at the boundary surface is set to 0.5 or less (preferably 0.4 or less). Therefore, as shown in FIG. 1, the acoustic signal for detection is reflected and transmitted at the boundary surface (the remainder of the reflected acoustic signal is transmitted), so that the smaller the sound pressure reflectance at the boundary surface, the more the transmitted acoustic signal can be increased, and the easier it is to transmit the acoustic signal for detection. This point is also true for the acoustic signal generated or scattered inside the subject. Therefore, by suppressing the sound pressure reflectance at the boundary surface through the combination of the metallic chip and the solid couplant, the acoustic sensor 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. EXAMPLES

[0050] As shown in FIG. 1, the acoustic sensor 12 was attached to the mold 11 by the attachment member 15. The attachment method was to fasten the metal tip 13 to the mold 11 by four fastening bolts (not shown) and press the solid couplant 14 against the mold 11. The mold 11 was made of steel, and the materials of the metal tip 13 and the solid couplant 14 of the attachment member 15 were changed to measure whether the reflection intensity of the acoustic signal (intensity of the reflected signal) could be detected. The measurement method was a method in which an acoustic signal for detection was supplied to the inside of the mold 11 by the acoustic sensor 12, and a reflected signal of the acoustic signal was detected by the acoustic sensor 12. The measurement results are shown in Table 1 and FIG. 5. For reference, the surface pressure estimated from the surface roughness and fastening torque of the metal tip 13 is shown in Table 1. FIG. 5 shows the measurement results when the force for fastening the metal tip 13 to the mold 11 satisfies the condition that the force is 1.1 times or more the product of the contact area between the mold 11 or the metal tip 13 and the solid couplant 14 and the yield strength of the solid couplant 14.

[0051] When the reflection intensity shown in Table 1 and Figure 5 is "◯", it means that an acoustic signal reflected from inside the mold could be detected, for example, as shown in Figure 2. When the reflection intensity shown in Table 1 and Figure 5 is "×", it means that an acoustic signal due to multiple reflections in the metal tip was detected, but the reflection intensity could not be detected accurately, for example, as shown in Figure 3. When the reflection intensity shown in Table 1 and Figure 5 is "△", it means that the contact state between the solid couplant and the metal tip or mold is one-sided, and a reflection intensity (acoustic signal) of "◯" or "×" is detected depending on the measurement position, for example, as shown in Figure 4. In addition, in Table 1 of this embodiment, the maximum pressing load is 25.7 kN, and the reflection intensity also depends on the manufacturing technology of the solid couplant. The surface pressure is calculated by taking the value at the time of measuring the reflection intensity as the proof stress (σ y ) is shown as a percentage. In Table 1, roughness*1 is the surface roughness of the metal tip measured using a non-contact roughness measurement method. Sq is the root mean square height, and Sa is the arithmetic mean height. Surface pressure*2 is the surface pressure (MPa) estimated from the tightening torque.

[0052] [Table 1]

[0053] From the measurement results in Table 1 and Fig. 5, it was found that the reflection intensity of an acoustic signal reflected from inside the mold can be detected by satisfying the conditions that the materials of the metallic tip 13 and the mold 11 are acoustically equivalent (i.e., the metallic tip 13 has an acoustic impedance within ±15% of the acoustic impedance of the mold 11) and the strength or hardness of the solid couplant 14 is equal to or less than the strength or hardness of the metallic tip 13. This is based on the measurement results when the combinations of the metallic tip and solid couplant in Table 1 and Fig. 5 are steel-solder, steel-zinc, steel-brass, steel-aluminum alloy, nickel-zinc, copper-zinc, copper-brass, and brass-zinc.

[0054] In addition, from the measurement results in Table 1 and FIG. 5, it was found that the reflection intensity of the acoustic signal reflected from inside the mold can be detected by satisfying the conditions that the solid couplant 14 has a thickness of 1.5 times or less than the wavelength of the acoustic signal propagating inside the solid couplant 14 and the strength or hardness of the solid couplant 14 is less than the strength or hardness of the metal tip 13. This is because the two conditions for the acoustic signal to pass through the three layers of the metal tip, solid couplant, and mold, that is, the removal of the air layer from the interface and the acoustic characteristics required for the solid couplant in the middle layer when the metal tip and the mold have similar acoustic characteristics, are satisfied. In other words, by making the thickness of the solid couplant 14 1.5 wavelengths or less, the air layer is removed from the interface by the plastic deformation of the entire solid couplant and the local flow to the uneven parts of the mold and metal tip surfaces, and the frequency distribution of the pulse wave sensor used widens the wavelength range of the acoustic signal that can pass through the three layers. It was found that this makes it possible to detect the acoustic signal generated and scattered inside the mold, or the acoustic signal reflected inside the mold. This is based on the results of measurements taken with the following combinations of metal tip and solid couplant in Table 1 and Figure 5: steel-solder, steel-zinc, steel-brass, steel-aluminum alloy, nickel-zinc, copper-zinc, copper-brass, and brass-zinc.

[0055] 5, it was found that even if the materials of the metallic tip 13 and the mold 11 are not acoustically equivalent (i.e., the metallic tip 13 has an acoustic impedance of more than ±15% of the acoustic impedance of the mold 11), the reflection intensity of the acoustic signal can be detected by satisfying the following conditions: the solid couplant 14 has an acoustic impedance within ±15% of the geometric mean value of the acoustic impedance of the metallic tip 13 and the acoustic impedance of the mold 11, the solid couplant 14 has a thickness of 1.5 times or less the wavelength of the acoustic signal propagating through the solid couplant 14, and the strength or hardness of the solid couplant 14 is less than the strength or hardness of the metallic tip 13. This is because the two conditions for the acoustic signal to pass through the three layers of the metallic tip, solid couplant, and mold, that is, the removal of an air layer from the interface, and the acoustic characteristics required for the solid couplant in the middle layer even when the acoustic impedances of the metallic tip and the mold are different, are satisfied. That is, by making the thickness of the solid couplant 14 1.5 wavelengths or less, the air layer is removed from the interface by plastic deformation of the entire solid couplant and local flow to the uneven parts of the mold and metal chip surfaces, and the frequency distribution of the pulse wave of the sensor used widens the wavelength range of the acoustic signal that can pass through the three layers. As a result, it was found that it is possible to detect acoustic signals generated and scattered inside the mold, or acoustic signals reflected within the mold. This is based on the measurement results when the combinations of metal chip and solid couplant in Table 1 and Figure 5 were aluminum alloy-solder, aluminum alloy-zinc, and aluminum alloy-brass.

[0056] Furthermore, from the measurement results in Table 1 and Fig. 5, it was found that the reflection intensity of an acoustic signal can be detected by satisfying the condition that the force for fastening the metallic tip 13 to the mold 11 is 1.1 times or more the product of the contact area between the mold 11 or the metallic tip 13 and the solid couplant 14 and the yield strength of the solid couplant 14. This is based on the measurement results when the combinations of the metallic tip and solid couplant in Table 1 and Fig. 5 are steel-solder, steel-zinc, steel-brass, steel-aluminum alloy, nickel-zinc, copper-zinc, copper-brass, brass-zinc, aluminum alloy-solder, aluminum alloy-zinc, and aluminum alloy-brass. [Explanation of symbols]

[0057] 11 Mold 12 Acoustic Sensor 13 Metal Tip 13a Cooling water supply path 14 Solid Couplant 15 Acoustic sensor mounting material 16 Wiring 17 Measuring Instruments

Claims

1. An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip.

2. An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is equal to or less than the strength or hardness of the metal tip.

3. In claim 1 or 2, the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is less than the strength or hardness of the metal tip.

4. An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is less than the strength or hardness of the metal tip.

5. An acoustic sensor mounting member disposed between an outer surface of a mold and an acoustic sensor for mounting the acoustic sensor to the mold, The attachment member has a metallic tip and a solid couplant; the metallic tip is in contact with the acoustic sensor; one side of the solid couplant contacts the metallic tip and the other side of the solid couplant contacts an outer surface of the mold; the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 13. A mounting member for an acoustic sensor, wherein the strength or hardness of the solid couplant is less than the strength or hardness of the metal tip.

6. In any one of claims 1, 2, 4 and 5, A mounting member for an acoustic sensor, characterized in that the force tightening the metal tip to the die is 1.1 times or more the product of the contact area between the die or the metal tip and the solid couplant and the yield strength of the solid couplant.

7. In any one of claims 1, 2, 4 and 5, 10. A mounting member for an acoustic sensor, comprising: a solid couplant made of a material having a sound pressure reflection coefficient of 0.5 or less.

8. In any one of claims 1, 2, 4 and 5, The solid couplant has a Vickers hardness of 15 or more and less than 100.

9. In any one of claims 1, 2, 4 and 5, 13. A mounting member for an acoustic sensor, wherein an outer surface of the mold and a surface of the metallic tip 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, 2, 4 and 5, A mounting member for an acoustic sensor, characterized in that when the temperature during molding using the mold is 100°C or higher, the mounting member has a function of cooling the acoustic sensor side of the metal chip.

11. In any one of claims 1, 2, 4 and 5, 11. An acoustic sensor mounting member, comprising: said metal tip having a function of pressing said solid couplant against said mold with a pressure of 20 MPa or more.

12. In any one of claims 1, 2, 4 and 5, An acoustic sensor mounting member, characterized in that the mold is made of steel.

13. A method for attaching an acoustic sensor to an outer surface of a mold using a mounting member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 11. A method for mounting an acoustic sensor, comprising the steps of: (a) providing a solid couplant with a resistance or hardness equal to or less than that of the metal tip;

14. A method for attaching an acoustic sensor to an outer surface of a mold using a mounting member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; the metallic tip has an acoustic impedance within ±15% of the acoustic impedance of the mold; 11. A method for mounting an acoustic sensor, comprising the steps of: (a) providing a solid couplant with a resistance or hardness equal to or less than that of the metal tip;

15. In claim 13 or 14, the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 11. A method for mounting an acoustic sensor, comprising the steps of: providing a solid couplant having a strength or hardness that is less than a strength or hardness of the metal tip;

16. A method for attaching an acoustic sensor to an outer surface of a mold using a mounting member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor for detecting an acoustic signal generated from or scattered within the inside of the specimen in the mold, The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 11. A method for mounting an acoustic sensor, comprising the steps of: providing a solid couplant having a strength or hardness that is less than a strength or hardness of the metal tip;

17. A method for attaching an acoustic sensor to an outer surface of a mold using a mounting member, comprising: a mounting member having a metallic tip for contacting a solid couplant, the mounting member being disposed between an outer surface of the mold and the acoustic sensor; The solid couplant and the metal tip are attached to the mold while being pressed against the mold with a pressure of 20 MPa or more. the acoustic sensor is a sensor that supplies an acoustic signal for detection to an inside of a test object in the mold and detects a reflected signal of the acoustic signal; The metallic tip has an acoustic impedance of more than ±15% of the acoustic impedance of the mold; the solid couplant has an acoustic impedance within ±15% of the geometric mean of the acoustic impedance of the metallic tip and the acoustic impedance of the mold; the solid couplant has a thickness that is less than or equal to 1.5 times the wavelength of the acoustic signal propagating through the solid couplant; 11. A method for mounting an acoustic sensor, comprising the steps of: providing a solid couplant having a strength or hardness that is less than a strength or hardness of the metal tip;

Images