Quality evaluation method

Abstract

To provide a quality evaluation method of making it easy to determine whether or not the quality of a member continuously manufactured is satisfactory and also making it easy to manufacture a member that satisfies the predetermined quality.SOLUTION: There are included: an information acquisition step S101 of acquiring member measurement information obtained by continuously measuring an eddy current along the length of a member continuously manufactured; signal acquisition steps S102 and S112 of dividing the continuous member into a plurality of lots and acquiring a switching signal corresponding to a border with the adjacent lot included in the plurality of lots; information division steps S104 and S114 of creating lot measurement information obtained by dividing the member measurement information for each lot based on the switching signal; and determination steps S105 and S115 of calculating an index value based on the magnitude of a value of the separated member measurement information included in the lot measurement information and determining the quality of the lot based on the calculated index value.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for evaluating the quality of continuously manufactured parts. [Background technology]

[0002] Known continuously manufactured components include components manufactured by rolling, etc. and components manufactured by casting, etc. For example, drawn wire rods are manufactured by reducing the diameter of thick wire rods in a wire drawing process using dies or a rolling process using rolls.

[0003] In addition, drawn wire material is made by continuously processing a large-diameter wire rod that has been joined together through processes such as wire drawing and rolling to reduce the diameter, and then cutting it into a specified length. In this way, drawn wire material can be produced stably and at low cost.

[0004] On the other hand, it is required to carry out quality control so that the quality of the produced drawn wire material in the continuous longitudinal direction is stable. Here, the quality of the drawn wire material includes the presence or absence of scratches on the surface of the drawn wire material.

[0005] A method of using an eddy current flaw detector that uses eddy currents is known as a method of controlling the quality of drawn wire material (see, for example, Patent Document 1). The eddy current flaw detector detects the presence or absence of flaws in the drawn wire material to be controlled. For example, the value of a signal output from the eddy current flaw detector (hereinafter also referred to as "output signal") changes depending on the size of the flaw in the drawn wire material. The quality of the drawn wire material is controlled based on the change in the value of this output signal.

[0006] To date, quality control methods using eddy current flaw detectors have included, for example, a method of evaluation based on the number of times the output signal value exceeds a predetermined threshold, and a method of continuously recording the change in the output signal value over time on chart paper and graphing the change in the output signal value for evaluation. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 8-166372 Summary of the Invention [Problem to be solved by the invention]

[0008] The above-mentioned output signal is analog data whose value changes continuously. When a computer is used to control the quality of the drawn wire material, the analog output signal is converted into digital data whose value changes discretely so that the signal can be processed by the computer (converted into a digital output signal).

[0009] In the process of converting the analog signal into digital data, if the sampling rate is not set appropriately, the following problems may occur. If the sampling rate is long, data related to scratches contained in the analog output signal may be lost from the digital output signal, making it difficult to control the quality. If the sampling rate is short, the amount of data in the digital output signal may be too large, making it difficult to organize the data used for quality control.

[0010] Furthermore, when quality control is performed by counting the number of times the value of the output signal exceeds a predetermined threshold, there is a problem in that it is difficult to determine whether the quality is good or bad because the length of the drawn wire material is not constant.

[0011] In other words, the length of the drawn wire product is determined according to customer requests, and may be long or short. If the drawn wire product is long, the number of times the threshold is exceeded is likely to be large, and if the drawn wire product is short, the number of times the threshold is exceeded is likely to be small. Thus, there is a problem in that it is difficult to quantitatively evaluate the drawn wire product by simply counting the number of signals that exceed the threshold, making it difficult to determine whether the quality is good or bad.

[0012] The present invention has been made to solve the above-mentioned problems, and aims to provide a quality evaluation method that makes it easier to determine the quality of continuously manufactured parts and makes it easier to manufacture parts that meet specified quality standards. [Means for solving the problem]

[0013] In order to achieve the above object, the present invention provides the following means: A quality evaluation method according to a first aspect of the present invention includes an information acquiring step of acquiring component measurement information obtained by continuously measuring eddy currents along the longitudinal direction of components manufactured in succession, a signal acquiring step of acquiring a switching signal corresponding to a boundary between adjacent lots among the components divided into a plurality of lots based on the lots, an information dividing step of creating lot measurement information by dividing the component measurement information corresponding to each lot based on the switching signal, and a determination step of calculating an index value based on the magnitude of values ​​of the plurality of component measurement information included in the lot measurement information, and determining the quality of the lot based on the calculated index value.

[0014] A manufacturing method according to a second aspect of the present invention is a method for manufacturing continuously manufactured components, comprising: a processing step for continuously manufacturing the components; an inspection step for continuously measuring eddy currents along the longitudinal direction of the manufactured components using an eddy current flaw detector; an information acquisition step for acquiring component measurement information output from the eddy current flaw detector; a signal acquisition step for dividing the continuous components into a plurality of lots and acquiring a switching signal corresponding to the boundary between adjacent lots among the plurality of lots; an information division step for creating lot measurement information by dividing the component measurement information corresponding to each lot based on the switching signal; and a judgment step for calculating an index value based on the magnitude of values ​​of a plurality of the component measurement information included in the lot measurement information, and judging the quality of the lot based on the calculated index value.

[0015] According to the quality evaluation method of the first aspect and the manufacturing method of the second aspect of the present invention, lot measurement information divided according to the lot is created, and the quality is judged using an index value based on the magnitude of the values ​​of the multiple discretized component measurement information included in the lot measurement information. For example, compared to a case where the quality is judged using component measurement information with a larger amount of data, the lot measurement information with a smaller amount of data due to division is used, so that it is easier to set the sampling rate when digitizing.

[0016] Quality is judged using an index value based on the magnitude of multiple discretized component measurement information values, making it easier to make a quantitative judgment by eliminating the influence of lot length compared to when evaluating by counting the number of times a threshold is exceeded. Effect of the Invention

[0017] According to the quality evaluation method of the present invention, lot measurement information is created which is divided corresponding to the lot, and quality is judged using an index value based on the magnitude of the values ​​of the multiple discretized component measurement information contained in the lot measurement information. This makes it easier to judge the quality of continuously manufactured components, and has the effect of making it easier to manufacture components which meet the specified quality. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram illustrating steps of a method for producing a drawn wire rod according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram for explaining an outline of the configuration of the eddy current flaw detector of FIG. 1. [Diagram 3] FIG. 2 is a block diagram illustrating the configuration of the quality evaluation device of FIG. [Figure 4] 1 is a flowchart illustrating a method for producing a drawn wire material. [Diagram 5] FIG. 13 is a schematic diagram illustrating a case where a drawn wire material has a scratch. [Figure 6] 1 is a flowchart illustrating a method for evaluating the quality of a product lot of a drawn wire material. [Figure 7] 1 is a flowchart illustrating a method for evaluating the quality of a material lot of a drawn wire material. [Figure 8] 4 is a graph illustrating the details of arithmetic processing of a digital measurement signal. [Figure 9] FIG. 11 is a diagram showing an example of quality data created for each material lot. [Figure 10] FIG. 11 is a diagram showing an example of quality data created for each product lot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] A method for manufacturing and evaluating the quality of a drawn wire material according to an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 10. In this embodiment, the object to be manufactured and evaluated for quality is a drawn wire material DM (corresponding to a component), but the object may be any component that is continuously manufactured, and is not limited to a drawn wire material. Components that are continuously manufactured include components manufactured using at least one of a wire drawing process using a die, a rolling process using rolls, a casting process, and the like.

[0020] First, the configurations of a production line 1 and a quality evaluation device 50 used in producing the drawn wire material DM will be described, and then the production method and the quality evaluation method will be described. Note that the quality evaluation device 50 may or may not be included in the production line 1. Fig. 1 is a schematic diagram for explaining the production process of the drawn wire material according to this embodiment.

[0021] The manufacturing line 1 continuously manufactures drawn wire material DM, which is a relatively thin wire material having a desired diameter (e.g., an outer diameter of 0.5 mm or more and 3.0 mm or less), from a wire rod WR (corresponding to a raw wire) which is a relatively thick wire material (e.g., an outer diameter of 6 mm or more and 15 mm or less). In this embodiment, the wire rod WR and drawn wire material DM are described as being copper wire material, but are not limited to copper as long as they are a conductive material such as iron or aluminum. The wire rod WR is manufactured in an upstream process different from the manufacturing line 1 and is supplied to the manufacturing line 1.

[0022] 1, the production line 1 is mainly provided with a delivery section 10, a wire drawing section 20, an eddy current flaw detector 30, a winding section 40, and a quality evaluation device 50. In this embodiment, an example will be described in which the production line 1 includes the quality evaluation device 50.

[0023] The delivery section 10 has a wire rod WR manufactured in an upstream process disposed therein, and supplies the wire rod WR to the wire drawing section 20. The configuration of the section in which the wire rod WR is disposed and the configuration of the section in which the wire rod WR is supplied to the wire drawing section 20 may be any known configuration, and the specific configuration is not limited thereto.

[0024] For example, a wire rod WR may be arranged for each material lot, which is a unit of continuous wire rod, or a wire rod WR connecting multiple material lots may be arranged in the delivery section 10. The wire rod WR may connect material lots produced in the same upstream process, or may connect material lots produced in different upstream processes.

[0025] The delivery section 10 may be provided with a configuration that enables connection of material lots, and connection of the material lots may be performed in the delivery section 10, or connection of the material lots may be performed at a location different from the delivery section 10. The material lots may be connected by a known connection method such as welding, and the specific connection method is not limited.

[0026] The wire drawing unit 20 converts the wire rod WR supplied from the delivery unit 10 into a drawn wire material DM. Specifically, the wire drawing unit 20 processes the wire rod WR by reducing its diameter to produce the drawn wire material DM. The wire drawing unit 20 may perform at least one of a wire drawing process using a die and a rolling process using rolls. Furthermore, the wire drawing unit 20 may include other processes.

[0027] The eddy current flaw detector 30 inspects the quality of the drawn wire material DM that has been processed to a desired diameter in the wire drawing section 20. Specifically, it is to measure whether or not there is any damage to the drawn wire material DM processed in the wire drawing section 20.

[0028] Fig. 2 is a schematic diagram for explaining an outline of the configuration of the eddy current flaw detector in Fig. 1. As shown in Fig. 2, the eddy current flaw detector 30 is mainly provided with a coil 31 and a flaw detection unit 32. In this embodiment, the eddy current flaw detector 30 is a single type using a single coil 31, and is a self-induction type in which excitation and detection are performed by the same single coil 31.

[0029] The method of using the eddy current flaw detector 30 may be a single method, a self-comparison method, or a standard comparison method. The induction method of the eddy current flaw detector 30 may be a self-induction method or a mutual induction method.

[0030] The coil 31 is a conductor wire arranged in a spiral shape. An AC current is supplied to the coil 31, and a flaw detector 32 that detects flaws in the drawn wire material DM is electrically connected to the coil 31. In this embodiment, the coil 31 is arranged so that the drawn wire material DM passes through the inside of the coil 31.

[0031] In other words, the description will be given by applying it to an example in which the eddy current flaw detector 30 is of a penetration type. Note that the coil 31 may be of a penetration type, or may be of a rotary type in which a plurality of (for example, two or four) coils 31 rotate around the drawn wire material DM.

[0032] The flaw detection unit 32 has a function as a power source for supplying an AC current to the coil 31, and a function for outputting a measurement signal (corresponding to component measurement information) of the drawn wire material DM to the quality evaluation device 50. In this embodiment, the description will be given by applying the present invention to an example in which the measurement signal is a voltage whose value changes depending on the presence or absence of a flaw, the size of the flaw, etc.

[0033] The measurement signal may be a voltage value, a current value, or an impedance value, and is not particularly limited. The configuration of the flaw detection unit 32 may be a known configuration, and the type, etc., of the flaw detection unit 32 is not limited.

[0034] The winding unit 40 winds up the drawn wire material DM after being inspected by the eddy current flaw detector 30. The winding unit 40 may have a known configuration, and is not limited to a specific configuration.

[0035] The quality evaluation device 50 evaluates the quality of the drawn wire material DM based on the measurement signal output from the eddy current flaw detector 30. Specifically, the quality evaluation device 50 performs quality evaluation regarding the presence or absence and size of flaws in the drawn wire material DM.

[0036] The quality evaluation device 50 is connected to the eddy current flaw detector 30 so as to be capable of communicating information with the device. In this embodiment, the description will be given of an example in which measurement signals are sequentially transmitted and received using a wired or wireless information communication device. Note that the measurement signals may be transferred from the eddy current flaw detector 30 to the quality evaluation device 50 using a portable information storage medium.

[0037] Fig. 3 is a block diagram for explaining the configuration of the quality evaluation device. As shown in Fig. 3, the quality evaluation device 50 is an information processing device such as a computer or a server having a CPU (Central Processing Unit), a ROM, a RAM, an input / output interface, etc. The program stored in the storage device such as the ROM causes the CPU, the ROM, the RAM, and the input / output interface to cooperate with each other to function as at least an information acquisition unit 51, a signal acquisition unit 52, an information division unit 53, a judgment unit 54, a data creation unit 55, and a condition comparison unit 56.

[0038] The information acquiring unit 51 acquires a measurement signal output from the eddy current flaw detector 30 that continuously measures eddy currents along the longitudinal direction of the drawn wire material DM. In this embodiment, an analog measurement signal is output from the eddy current flaw detector 30 and converted into a digital measurement signal in the information acquiring unit 51. The position where the analog measurement signal is converted into a digital measurement signal may be the information acquiring unit 51 as described above or may be the eddy current flaw detector 30, and the position is not limited. In other words, the information acquiring unit 51 may acquire a digital measurement signal output from the eddy current flaw detector 30.

[0039] The signal acquiring unit 52 acquires a switching signal corresponding to a boundary between adjacent lots among a plurality of lots. A lot is a unit into which a drawn wire material DM (or a wire rod WR), which is a long material, is divided into a plurality of parts in the longitudinal direction. A boundary is a boundary between adjacent lots, for example, a part where a nth lot switches to an n+1th lot (hereinafter, n is an integer of 1 or more).

[0040] The switching signals acquired by the signal acquiring unit 52 include a product switching signal and a material switching signal. The switching signal is a signal obtained by detecting the boundary between adjacent lots. In this embodiment, the present invention will be described as being applied to a method of detecting the boundary between adjacent lots based on the diameter of the drawn wire material DM, the weight per unit volume, and the weight of each lot calculated from the lot length.

[0041] The method for detecting the boundary between adjacent lots may be a method for detecting a trace of joining wire rods present on the drawn wire rod DM as the boundary between adjacent lots, a method for detecting the boundary between adjacent lots based on the length of the drawn wire rod DM being sent out and the length of the lot, or a method for detecting a physical mark such as a marking provided on the drawn wire rod DM as the boundary between adjacent lots.

[0042] The product switching signal is a signal output from the product switching signal output unit 45, and corresponds to the boundary between adjacent product lots among multiple product lots. A product lot is a unit into which a continuous drawn wire material DM is divided in the longitudinal direction. A product lot is also a unit sold as a product. The product switching signal is a signal obtained by detecting the boundary between adjacent product lots among multiple product lots. For example, the product switching signal is a signal obtained by detecting the portion where the nth product lot switches to the n+1th product lot.

[0043] The material switching signal is a signal output from the material switching signal output unit 15, and corresponds to the boundary between adjacent material lots among a plurality of material lots. A material lot is a unit into which the drawn wire material DM is divided in the length direction, and corresponds to the plurality of wire rods WR used to form the drawn wire material DM. The material switching signal is a signal obtained by detecting the boundary between adjacent material lots among a plurality of material lots. For example, the material switching signal is a signal obtained by detecting the portion where the nth material lot is switched to the n+1th material lot.

[0044] The product switching signal output unit 45 is disposed near the winding unit 40 and is connected to enable signal communication with the quality evaluation device 50. The product switching signal output unit 45 outputs a product switching signal that is a signal corresponding to the boundary between adjacent product lots.

[0045] The product switching signal output unit 45 may be located near the winding unit 40 as described above, or may be located away from the winding unit 40 as long as it is capable of outputting a product switching signal.

[0046] In this embodiment, the product switching signal output unit 45 outputs a product switching signal based on the weight of the drawn wire material DM wound around the winding unit 40. Specifically, a product switching signal is output based on the weight of each product lot calculated from the diameter, weight per unit volume, and length of the drawn wire material DM, indicating that the product lot has been switched. For example, a product switching signal is output indicating that the nth product lot has been switched to the n+1th product lot.

[0047] The method by which the product switching signal output unit 45 outputs the product switching signal is not limited to the above-mentioned method, and various other methods capable of outputting the product switching signal may be used.

[0048] The material switching signal output unit 15 is disposed near the sending unit 10 and is connected to the quality evaluation device 50 so as to be able to communicate signals with the quality evaluation device 50. The material switching signal output unit 15 outputs a material switching signal which is a signal corresponding to the boundary between material lots.

[0049] In this embodiment, the material switching signal output unit 15 detects a joint that is a boundary between adjacent material lots in the wire rod WR, and outputs a material switching signal indicating that the material lot has been switched. Note that the method by which the material switching signal output unit 15 outputs the material switching signal is not limited to the above-mentioned method, and various other methods capable of outputting a material switching signal may be used.

[0050] The information division unit 53 creates product lot measurement information (corresponding to lot measurement information) by dividing the multiple measurement signals (corresponding to component measurement information) acquired by the information acquisition unit 51 according to each product lot based on the product switching signal. In other words, it determines the boundary between product lots in the multiple measurement signals based on the product switching signal, and creates product lot measurement information by dividing the multiple measurement signals at the boundary between product lots. Specific calculation processing will be described later.

[0051] For example, product lot measurement information corresponding to the nth product lot includes multiple measurement signals measured from the boundary between the n-1th product lot and the nth product lot to the boundary between the nth product lot and the n+1th product lot.

[0052] Further, the information division unit 53 creates material lot measurement information (corresponding to lot measurement information) by dividing the multiple measurement signals (corresponding to component measurement information) acquired by the information acquisition unit 51 according to each material lot based on the material switching signal. In other words, it determines the boundary between material lots in the multiple measurement signals based on the material switching signal, and creates material lot measurement information by dividing the multiple measurement signals at the boundary between material lots. Specific calculation processing will be described later.

[0053] For example, material lot measurement information corresponding to the nth material lot includes multiple measurement signals measured from the boundary between the n-1th material lot and the nth material lot to the boundary between the nth material lot and the n+1th material lot.

[0054] The judgment unit 54 performs a calculation process to calculate an index value based on the magnitude of the values ​​(hereinafter, also referred to as "output values") of a plurality of discretized measurement signals included in the product lot measurement information and the material lot measurement information. It also performs a calculation process to judge the quality of the product lot and the material lot based on the calculated index value. The details of the calculation process in the judgment unit 54 will be described later.

[0055] In this embodiment, the index value is a value indicating the variation in the magnitude of a plurality of output values. More specifically, the index value is a standard deviation. The index value may be a standard deviation or may be a value indicating another variation such as variance.

[0056] Furthermore, the index value may be a value indicating the variation in the magnitude of multiple output values, such as a standard deviation, or a value representing the magnitude of the values ​​among the multiple output values, such as the average or median of the magnitude of the output values.

[0057] The data creation unit 55 creates quality data for each product lot of the drawn wire material DM based on the judgment result in the judgment unit 54. Also, the data creation unit 55 creates quality data for each material lot of the drawn wire material DM based on the judgment result in the judgment unit 54.

[0058] The condition comparison unit 56 compares manufacturing conditions in the upstream process of manufacturing the wire rod WR, based on the quality data for each material lot created by the data creation unit 55. The processing contents of the data creation unit 55 and the condition comparison unit 56 will be described later.

[0059] Next, a method for producing the drawn wire material DM and a method for evaluating the quality thereof in this embodiment will be described. The drawn wire material DM is produced from a wire rod WR in a production line 1 shown in Fig. 1. Fig. 4 is a flow chart for explaining the method for producing the drawn wire material DM.

[0060] First, as shown in Fig. 1 and Fig. 4, a wire rod WR manufactured in an upstream process is supplied to a production line 1 (supply step S10). Specifically, the wire rod WR manufactured in an upstream process is placed in a delivery section 10. The wire rod WR, to which a plurality of material lots have been connected in advance, may be placed in the delivery section 10, or the wire rod WR may be delivered for each material lot. section 10 and may be connected to other material lots already located in the delivery section 10.

[0061] Next, the wire rod WR sent out from the sending-out unit 10 is processed into a drawn wire material DM (processing step S20). Specifically, in the wire drawing unit 20, processing is performed to reduce the diameter of the wire rod WR to produce the drawn wire material DM. At least one of a wire drawing process using a die and a rolling process using rolls is used as the process to reduce the diameter.

[0062] Next, the drawn wire material DM produced in the wire drawing section 20 is inspected (corresponding to measuring eddy currents) using an eddy current detector 30 (inspection step S30). Specifically, as shown in FIG. 2, the drawn wire material DM is passed through a coil 31 of the eddy current detector 30.

[0063] An AC current is applied to the coil 31 from the flaw detection unit 32. An eddy current EC is generated on the surface of the drawn wire material DM passed through the coil 31 due to the magnetic field generated from the coil 31 to which the AC current is applied. Furthermore, the magnetic field generated by the eddy current EC is detected by the coil 31 and the flaw detection unit 32, and the flaw detection unit 32 outputs a measurement signal of a voltage corresponding to the eddy current EC.

[0064] 5, when a flaw SH is present on the surface of the drawn wire material DM, the eddy current EC flows around the flaw SH, and the magnitude of the eddy current EC changes. The change in the magnitude of the eddy current EC is detected by the coil 31 and the flaw detection unit 32, and the voltage of the measurement signal output from the flaw detection unit 32 also changes. In this embodiment, an example will be described in which the voltage of the measurement signal increases when a flaw SH is present on the surface of the drawn wire material DM.

[0065] After the inspection using the eddy current flaw detector 30, the drawn wire material DM is wound around the winding section 40 (winding step S40). This completes the production of the drawn wire material DM in the production line 1. The drawn wire material DM wound around the winding section 40 is then separated into individual product lots.

[0066] Further, in the inspection step S30, a process of evaluating the quality of the drawn wire material DM is performed based on the measurement signal output from the eddy current flaw detector 30 (quality evaluation step S100).

[0067] Fig. 6 is a flowchart for explaining a quality evaluation method for a product lot of drawn wire material DM. Fig. 7 is a flowchart for explaining a quality evaluation method for a material lot of drawn wire material DM. First, the calculation process for evaluating the quality of a product lot will be described with reference to Fig. 6. Then, the calculation process for evaluating the quality of a material lot will be described with reference to Fig. 7.

[0068] In this embodiment, the calculation process for evaluating the quality of a product lot and the calculation process for evaluating the quality of a material lot are performed in parallel. For ease of explanation, the two processes are described separately using Figures 6 and 7, but the calculation process may be performed based on a flowchart that combines the two processes.

[0069] 6, the quality evaluation device 50 performs a process of acquiring a measurement signal, which is continuous data output from the eddy current flaw detector 30 (information acquisition step S101). Specifically, the information acquisition unit 51 of the quality evaluation device 50 acquires an analog measurement signal output from the flaw detection unit 32 of the eddy current flaw detector 30. The information acquisition unit 51 performs a process of converting the acquired analog measurement signal into a digital measurement signal.

[0070] Furthermore, the quality evaluation device 50 performs a process of acquiring a product switching signal (signal acquisition step S102). Specifically, the signal acquisition unit 52 of the quality evaluation device 50 acquires the product switching signal output from the product switching signal output unit 45.

[0071] Thereafter, the quality evaluation device 50 performs a calculation process to compare the digital measurement signal with the product switching signal (S103). Specifically, the information dividing unit 53 of the quality evaluation device 50 performs a calculation process to compare the digital measurement signal with the product switching signal based on time information included in the digital measurement signal and the product switching signal.

[0072] Furthermore, the information dividing unit 53 performs a calculation process to determine a joint portion, which is a boundary between product lots in the digital measurement signal. In the process of determining the joint portion, it is preferable to take into consideration the time difference between when the drawn wire material DM is inspected by the eddy current flaw detector 30 and when the boundary between the product lots is detected by the product switching signal output unit 45.

[0073] After the collation process, the quality evaluation device 50 performs a calculation process to create product lot measurement information by dividing the digital measurement signal corresponding to the product lot (information division step S104). Specifically, the information division unit 53 performs a calculation process to divide the digital measurement signal at the connection portion that is the boundary between product lots in the digital measurement signal determined in S103.

[0074] When the product lot measurement information is created, the quality evaluation device 50 performs a calculation process to determine the quality of each product lot (in other words, each piece of product lot measurement information) (determination step S105). In this embodiment, the description will be given by applying the description to an example in which the determination unit 54 of the quality evaluation device 50 performs a quality determination process based on a threshold value for each piece of product lot measurement information and a quality determination process using a standard deviation as an index value.

[0075] In the quality judgment process based on a threshold value, the judgment unit 54 judges whether or not the voltage value in the product lot measurement information exceeds a predetermined threshold value. The number of times that the voltage value in the product lot measurement information exceeds the predetermined threshold value is linked to the product lot measurement information and stored. Here, the voltage value in the product lot measurement information is a value that increases according to the size of the flaw SH in the drawn wire material DM.

[0076] The threshold value used for the determination may be one or more. In this embodiment, an example will be described in which two threshold values ​​are used: a threshold value (small) corresponding to a small scratch SH and a threshold value (large) corresponding to a large scratch SH.

[0077] In the quality judgment process using the standard deviation as an index value, the judgment unit 54 performs a calculation process to obtain a standard deviation with the voltage value in the product lot measurement information as a population. The value of the standard deviation obtained by the calculation process is linked to the product lot measurement information that was the subject of the calculation process and stored. Note that a known calculation method can be used to calculate the standard deviation, and the calculation method is not limited to a specific one.

[0078] After the calculation process for quality judgment for each product lot is performed, the quality evaluation device 50 performs a calculation process for creating quality data for each product lot of the drawn wire material DM (S106). Specifically, the data creation unit 55 of the quality evaluation device 50 creates quality data that summarizes the number of times the voltage value exceeded a predetermined threshold value and the standard deviation value for each product lot (in other words, for each product lot measurement information).

[0079] The created quality data may be displayed on a display device such as a display provided in the quality evaluation device 50, may be output to a storage device, or may be output to another information processing device connected for information communication.

[0080] Next, the calculation process for evaluating the quality of a material lot will be described. As shown in Fig. 7, the quality evaluation device 50 performs a process for acquiring a measurement signal, which is continuous data output from the eddy current flaw detector 30 (S101). The specific contents of the process are similar to the calculation process for evaluating the quality of a product lot, and therefore a description thereof will be omitted.

[0081] Furthermore, the quality evaluation device 50 performs a process of acquiring a material switching signal (signal acquisition step S112). Specifically, the signal acquisition unit 52 of the quality evaluation device 50 acquires the material switching signal output from the material switching signal output unit 15.

[0082] Thereafter, the quality evaluation device 50 performs a calculation process to compare the digital measurement signal with the material switching signal (S113). Specifically, the information dividing unit 53 of the quality evaluation device 50 performs a calculation process to compare the digital measurement signal with the material switching signal based on time information included in the digital measurement signal and the material switching signal, and to determine a connection portion that is a boundary between material lots in the digital measurement signal.

[0083] In the process of determining the joint, it is preferable to take into consideration the time difference between when the material switching signal output unit 15 detects the boundary between the material lots and when the drawn wire material DM is inspected by the eddy current flaw detector 30.

[0084] After the collation process, the quality evaluation device 50 performs a calculation process to create material lot measurement information by dividing the digital measurement signal corresponding to the material lot (information division step S114). Specifically, the information division unit 53 performs a calculation process to divide the digital measurement signal at the connection portion that is the boundary between material lots in the digital measurement signal determined in S113.

[0085] When the material lot measurement information is created, the quality evaluation device 50 performs a calculation process for determining the quality of each material lot (in other words, each piece of material lot measurement information) (determination step S115).

[0086] In this embodiment, the description will be given by applying it to an example in which the judgment unit 54 of the quality evaluation device 50 performs a quality judgment process based on a threshold value and a quality judgment process using a standard deviation as an index value for each material lot measurement information. Note that the process contents of the quality judgment process based on a threshold value and the quality judgment process using a standard deviation as an index value are similar to the process contents in S105, and therefore the description thereof will be omitted.

[0087] After the calculation process for quality judgment for each material lot is performed, the quality evaluation device 50 performs a calculation process for creating quality data for each material lot of the drawn wire material DM (S116). Specifically, the data creation unit 55 of the quality evaluation device 50 creates quality data that summarizes the number of times the voltage value exceeded a predetermined threshold and the standard deviation value for each material lot (in other words, for each piece of material lot measurement information).

[0088] After the calculation process for creating the quality data is performed, the quality evaluation device 50 performs a calculation process for comparing the manufacturing conditions of the upstream process (S117). Specifically, the condition comparison unit 56 of the quality evaluation device 50 compares the manufacturing conditions in the upstream process for manufacturing the wire rod WR, based on the quality data for each material lot.

[0089] The comparison results of the manufacturing conditions may be displayed on a display device such as a display provided in the quality evaluation device 50, may be output to a storage device, or may be output to another information processing device connected so as to be capable of communicating information.

[0090] Next, an example of the calculation process of the digital measurement signal in the quality evaluation device 50 will be described. Fig. 8 is a graph for explaining the contents of the calculation process of the digital measurement signal. In the graph shown in Fig. 8, the horizontal axis is the length of the drawn wire material DM, and the vertical axis is the level indicating the size of the flaw SH. The level of the flaw SH is also the magnitude of the voltage in the measurement signal. In Fig. 8, the description will be applied to an example in which the wire rod WR is a copper wire material with an outer diameter of 8 mm, and the drawn wire material DM is a copper wire material with an outer diameter of 2.6 mm.

[0091] The graph shown in Figure 8 shows product switching signals indicated by vertically extending dotted lines. Product lots are shown as the portions sandwiched between the product switching signals. Figure 8 shows product lots (1) to (13).

[0092] Furthermore, multiple material lots are shown at the top of the graph in Fig. 8. In Fig. 8, material lots A-1 to A-4, B-1 and B-2 are shown. The boundaries between the material lots correspond to the material switching signal.

[0093] The material lots A-1 through A-4 have the same alphabet, which indicates that they are lots manufactured in the same upstream process. The numbers also indicate that they are different lots. The material lots B-1 and B-2 have different alphabets from A-1 through A-4, which indicates that they are lots manufactured in different upstream processes.

[0094] In addition, the graph shown in Fig. 8 illustrates a threshold value (small) and a threshold value (large) used to judge the quality. The values ​​of the threshold value (small) and the threshold value (large) can be set appropriately, and the values ​​are not limited. The number of threshold values ​​is also not limited to two, and may be one, or three or more.

[0095] Next, a description will be given of the quality data created by the quality evaluation device 50. Fig. 9 shows an example of quality data created for each material lot, and Fig. 10 shows an example of quality data created for each product lot.

[0096] As shown in Figure 9 Looking at the number of large and small scratches in the quality data created for each material lot, materials A-1 to A-4 have one or more large and small scratches, while materials B-1 and B-2 have zero large and zero small scratches. Also, looking at the standard deviation, materials A-1 to A-4 have a standard deviation of 0.096 or more, while materials B-1 and B-2 have a standard deviation of 0.018 or less.

[0097] In other words, it can be seen that the occurrence conditions of scratches SH on the surface of the drawn wire material DM differ between materials A-1 to A-4 and materials B-1 and B-2, as is clearly reflected in the number of scratches (large) and scratches (small) and the standard deviation.

[0098] As shown in Figure 10, by focusing on the number of scratches (large) and scratches (small) in the quality data created for each product lot, it is possible to determine whether or not there is an unexpected scratch SH, but it is difficult to grasp the overall trend, such as the frequency of occurrence of scratches SH. On the other hand, by focusing on the standard deviation, it is relatively easy to grasp the overall trend, such as the frequency of occurrence of scratches SH.

[0099] According to the above-mentioned manufacturing method and quality evaluation method, product lot measurement information divided according to the product lot is created, and the quality of the product lot is judged using the standard deviation, which is an index value based on the magnitude of the output value included in the product lot measurement information. Also, material lot measurement information divided according to the material lot is created, and the quality of the material lot is judged using the standard deviation, which is an index value based on the magnitude of the output value included in the material lot measurement information.

[0100] As a result, for example, compared to a case where quality is judged using the measurement signal of the drawn wire material DM, which has a larger amount of data, the measurement signal of the drawn wire material DM is divided to use product lot measurement information and material lot measurement information, which have a smaller amount of data, making it easier to set the sampling rate when converting analog data into digital data. For example, it becomes easier to set an appropriate sampling rate based on the moving speed of the drawn wire material DM and the length of the product lot and material lot. In addition, it becomes possible to appropriately compress the product lot measurement information and the information indicating the presence or absence of scratches in the material lot measurement information to the extent that such information is not lost.

[0101] The quality of the drawn wire material DM is judged using the standard deviation, which makes it easier to perform a quantitative judgment by eliminating the influence of lot length compared to the case where the evaluation is performed by only counting the number of times the threshold is exceeded. In addition, by combining the method of evaluation by counting the number of times the threshold is exceeded, it becomes even easier to perform a quantitative judgment. Therefore, it becomes easier to manufacture the drawn wire material DM that meets the specified quality.

[0102] By using a product switching signal that corresponds to the boundary between the product lots of wire drawn DM, the quality of each product lot can be quantified and visualized, making it easier to judge the quality. In addition, the judged quality can be fed back to the manufacturing process of wire drawn DM, making it easier to manufacture wire drawn DM that meets the specified quality.

[0103] By using a material switching signal that corresponds to the boundary between material lots of the drawn wire material DM, the quality of the wire rod WR before it becomes the drawn wire material DM can be quantified and visualized, making it easier to judge the quality. In addition, the judged quality can be fed back to the wire rod WR manufacturing process, making it easier to manufacture drawn wire material DM that meets the specified quality.

[0104] By using the standard deviation, which indicates the variation, to judge the quality, it becomes easier to quantitatively judge the quality of a product lot or a material lot, compared to using the number of times a threshold value is exceeded. In other words, it becomes easier to eliminate the influence of the length of a product lot or a material lot when making a judgment.

[0105] In addition, when the average or median of the output values ​​is used to judge the quality, the amount of calculation required for the judgment can be reduced compared to when standard deviation or variance, which indicates the variation, is used. Therefore, it is easy to perform the quality evaluation of the product lot or material lot more quickly.

[0106] The technical scope of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the above-mentioned embodiment has been described as being applied to an example in which quality evaluation is performed on both product lots and material lots, but quality evaluation may be performed on either the product lot or the material lot. [Explanation of symbols]

[0107] 30... Eddy current flaw detector, DM... Drawn wire material (component), WR... Wire rod (wire material), S20... Processing step, S30... Inspection step, S40... Winding step, S100... Quality evaluation step, S101... Information acquisition step, S102, S112... Signal acquisition step, S104, S114... Information division step, S105, S115... Judgment step

Claims

1. A quality evaluation method comprising: an information acquisition step of acquiring component measurement information obtained by continuously measuring eddy currents along the longitudinal direction of components manufactured in succession; a signal acquisition step of acquiring a switching signal corresponding to a boundary between adjacent lots from the components divided into a plurality of lots by the lot; an information division step of creating lot measurement information by dividing the component measurement information corresponding to each lot based on the switching signal; and a judgment step of calculating an index value based on the magnitude of the values ​​of the plurality of component measurement information included in the lot measurement information, and judging the quality of the lot based on the calculated index value.

2. 2. The quality evaluation method according to claim 1, wherein the switching signal corresponds to a boundary between adjacent product lots among a plurality of product lots which are products obtained by dividing the continuous member.

3. The quality evaluation method according to claim 1, wherein the wires in the component, which are a connection of a plurality of wires, correspond to a plurality of material lots, respectively, and the switching signal is a signal corresponding to a boundary between adjacent material lots in the plurality of material lots.

4. The quality evaluation method according to claim 1 , wherein the index value is a value indicating a variation in magnitude of values ​​of the plurality of pieces of discretized component measurement information in the lot measurement information.

5. The quality evaluation method according to claim 1 , wherein the index value is an average value or a median value of the magnitudes of the plurality of discretized values ​​of the component measurement information in the lot measurement information.

Images