Rough drawing wire, enamel wire, and method for producing enamel wire

Abstract

To provide a rough drawing wire capable of forming a high-quality enamel wire with suppressed surface oxidation, an enamel wire formed with the rough drawing wire, and a method for producing the enamel wire.SOLUTION: This is a rough drawn wire primarily composed of copper, and the oxidation degree measured on the surface of the rough drawn wire is less than 25. The measurement of the oxidation degree involves creating a histogram from the peak areas of Raman spectrum peaks at each pixel of a mapping image obtained through Raman spectrum mapping processing. From this histogram, the average value of multiple peak areas is calculated, which is used as the oxidation degree. The multiple Raman spectrum peaks correspond to the lattice vibrations of the vibrational mode 2Eu of Cu2O. The histogram is structured with the range of peak areas from minimum to maximum divided into 256 classes on the horizontal axis, and the frequency, which is the number of pixels for each class, on the vertical axis, thus providing the rough drawn wire.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a rough-drawn wire, an enameled wire, and a method for manufacturing an enameled wire.

Background Art

[0002] Conventionally, a method for manufacturing an enameled wire in which an enamel coating made of polyimide or polyamideimide is formed on the surface of a linear conductor is widely known (see, for example, Patent Document 1).

[0003] As the conductor of the enameled wire, a rough-drawn wire in a state called a stripping material, in which the oxide film on the surface is peeled off from a rough-drawn wire called a wire rod, is usually used. The reason for using the stripping material with the oxide film peeled off as the conductor material is to improve the adhesion to the enamel paint and the appearance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, oxidation of the surface of the stripping material proceeds immediately after the oxide film is peeled off. Therefore, if management is not performed under appropriate storage conditions (temperature, humidity, time), oxidation of the surface of the stripping material is promoted and discoloration occurs.

[0006] The stripping material is subjected to processing steps such as wire drawing, rolling, and flat wire drawing, and an enamel coating step. Generally, the processing lines for performing these processes do not include a device for peeling the oxide film, and there is no step of peeling the oxide film on the surface again from the stripping material. Therefore, when discoloration occurs in the stripping material, defects in appearance due to discoloration of the conductor remain even after a semi-transparent enamel coating is formed.

[0007] Furthermore, according to the inventors' research, it has been confirmed that in a rough wire drawn with oxidation on the surface of discolored peeled material, etc., the oxidation embrittles the conductor surface, causing cracks in the oxide coating with low elongation during drawing, and the amount of copper powder (wear powder) generated increases.The inventors have also found that the copper powder adhering to the surface of the conductor obtained by drawing a rough wire is prone to trap microscopic air bubbles, and that the microscopic air bubbles expand in volume (foam) as the solvent evaporates during baking after enamel coating, causing the enameled wire to have a poor appearance.

[0008] In order to prevent such defects in the appearance of enameled wire, it is necessary to use a rough wire rod with reduced surface oxidation, such as a stripped material that has reduced surface oxidation after the oxide coating is removed, in the manufacturing process of the enameled wire.

[0009] An object of the present invention is to provide a wire rod having suppressed surface oxidation, which can form a high-quality enameled wire, an enameled wire formed using the wire rod, and a method for manufacturing the enameled wire. [Means for solving the problem]

[0010] The present invention aims to solve the above-mentioned problems, and provides a wire rod mainly composed of copper, the surface of which is measured by Raman spectroscopy to have a degree of oxidation of less than 25, the degree of oxidation being measured by performing a mapping process of a Raman spectrum under the following conditions, creating a histogram from the peak areas of Raman spectrum peaks in each pixel of the obtained mapping image, calculating an average value of a plurality of the peak areas from the histogram, and measuring the average value as the degree of oxidation, the plurality of Raman spectrum peaks being Cu 2 O vibration mode 2E u The histogram is a rough line plot of 256 classes obtained by dividing the range from the minimum value to the maximum value of the peak areas into 256 classes on the horizontal axis and a frequency, which is the number of pixels for each class, on the vertical axis. Raman measurement equipment: Nanophoton RAMANforce Standard VIS-NIR-HS Laser wavelength: 532.06 nm Width of the incident slit of the spectroscope: 50 μm Ratio of the light quantity after attenuation to the maximum laser light quantity of the ND filter (attenuation ratio): 215 / 255 Number of rulings of the diffraction grating: 600 gr / mm Magnification of the objective lens: 100 times Numerical aperture (NA): 0.9 Mapping range: 88 × 60 μm Pixel size: 2 × 2 μm

[0011] Further, the present invention provides an enameled wire including a conductor formed by drawing the above-mentioned rough drawn wire and an insulating coating provided around the conductor, for the purpose of solving the above problems.

[0012] Further, the present invention includes, for the purpose of solving the above problems, a mapping process of irradiating a laser on the surface of a rough drawn wire whose main component is copper and performing mapping processing on the Raman spectrum, and Cu contained in each pixel of the mapping image obtained by the mapping process 2 The lattice vibration of O's vibration mode 2E u A histogram of the peak area of the peak attributed to the lattice vibration is created, and the degree of oxidation of the surface of the rough drawn wire is evaluated using the average value of the peak area obtained from the histogram. After the evaluation process, a drawing process of drawing the rough drawn wire, and after the drawing process, an enamel paint is applied to the surface of the conductor formed by drawing the rough drawn wire and fired to form an insulating coating around the conductor. A method for manufacturing an enameled wire is provided, wherein the drawing process and the coating formation process are carried out when a predetermined result is obtained in the evaluation process.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide a rough drawn wire with suppressed surface oxidation, an enameled wire formed using the rough drawn wire, and a method for manufacturing the enameled wire, which can form high-quality enameled wire.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0015] (Characteristics of the Rough-drawn Wire) The rough-drawn wire according to the present invention is a rough-drawn wire with suppressed surface oxidation and having copper as the main component of the whole, and is typically a stripping material. The stripping material refers to a rough-drawn wire in a state where the surface oxide film has been peeled off from a rough-drawn wire called a wire rod. Hereinafter, as an embodiment of the present invention, the stripping material will be described. The stripping material according to an embodiment of the present invention is referred to as stripping material 1. Note that the main component being copper means, for example, that the copper concentration is 99.9% or more.

[0016] The stripping material 1 used as the conductor of the enameled wire is subjected to processing such as round drawing, rectangular drawing, rolling, and the formation of an insulating film on its surface. The degree of oxidation on the surface of the stripping material 1 immediately before processing such as drawing or rolling is preferably less than 25. Here, the degree of oxidation is a parameter indicating the degree of oxidation obtained by Raman scattering measurement. Details of the degree of oxidation will be described later. Note that since the measurement of the degree of oxidation of the stripping material 1 described later can be similarly performed on the rough-drawn wire without stripping, the rough-drawn wire according to the present invention can have a degree of oxidation less than 25 on the surface immediately before processing, including those without stripping.

[0017] Figs. 1(a) and (b) are examples of photographs showing the appearance of the stripping material. The stripping material shown in Fig. 1(a) has a surface oxidation degree of 21.84 and corresponds to the stripping material 1 according to the embodiment of the present invention. In the stripping material shown in Fig. 1(a), almost no discoloration of the surface is observed, indicating that the surface oxidation is suppressed.

[0018] On the other hand, the stripping material shown in Fig. 1(b) has a surface oxidation degree of 102.6 and does not correspond to the stripping material 1 according to the embodiment of the present invention. In the stripping material shown in Fig. 1(b), discolored and blackened portions are seen here and there, indicating that a certain degree of oxidation has occurred on the surface.

[0019] The stripping material 1 can be used as the material for the conductor of the enameled wire. For example, after drawing the stripping material 1, a paint such as polyimide or polyamideimide is applied to the surface of the stripping material 1 and fired to produce an enameled wire with an enamel film formed around the stripping material 1. That is, according to the embodiment of the present invention, an enameled wire including a conductor made of the stripping material 1 and an insulating film provided around the conductor can be provided.

[0020] Figure 2 is a radial cross-sectional view of the enameled wire 100 according to an embodiment of the present invention. The enameled wire 100 shown in Figure 2 is an enameled wire having a rectangular cross-sectional shape, including a flat wire-shaped conductor 10 formed by flattening a rough-drawn wire such as a stripping material 1, and an insulating coating 11 formed around the conductor 10. Note that the enameled wire 100 may be an enameled wire having a circular cross-sectional shape. In that case, the conductor 10 is formed by rounding a rough-drawn wire such as the stripping material 1.

[0021] The stripping materials shown in FIGS. 1(a) and 1(b) are stripping materials with a diameter of 6.3 mm used as raw materials for flat enameled wire conductors. They are obtained by peeling the surface oxide film (stripping) from a wire rod with a diameter of 8 mm and applying a lubricant. The wire rod as the raw material is oxygen-free copper (OFC) manufactured by Showa Electric Wire & Cable System Co., Ltd.'s dip forming system.

[0022] (Measurement of oxidation degree) The oxidation degree means that a laser is irradiated on the surface of the stripping material to perform Raman spectrum mapping processing, and for each pixel of the obtained mapping image, the Cu 2 O vibration mode 2E u peak (hereinafter referred to as the Cu 2 O peak). A histogram is created with the horizontal axis being the classes obtained by dividing the range from the minimum value to the maximum value of the peak area into 256, and the vertical axis being the frequency, which is the number of pixels for each class. The average value of the peak area of the Cu 2 O peak obtained from the histogram is meant.

[0023] The mapping process in the above definition of the oxidation degree is carried out using a Raman measurement device (RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton), with a laser wavelength of 532.06 nm, an incident slit width of the spectroscope of 50 μm, the ratio of the light intensity after attenuation to the maximum light intensity of the laser of the ND filter (attenuation ratio) of 215 / 255, the number of rulings of the diffraction grating of 600 gr / mm, the magnification and numerical aperture (NA) of the objective lens being 100 times and 0.9 respectively, and the mapping range and pixel size being 88×60 μm and 2×2 μm respectively (i.e., the number of pixels of the mapping image is 1320).

[0024] As described above, since the oxidation degree of the surface of the stripping material is measured by Raman spectroscopic analysis that measures Raman scattered light, the oxidation degree of the surface can be evaluated non-contact without destroying the stripping material. Also, in the measurement of the oxidation degree, since the peak area of the Cu 2 O peak of the Raman spectrum is used, the oxidation degree of the surface of the stripping material can be accurately evaluated. For example, when analyzing the components of the surface of the stripping material by elemental analysis, since information on oxygen other than the oxygen contained in the copper oxide is mixed and obtained, it is difficult to accurately evaluate the oxidation degree.

[0025] The following describes a specific measurement procedure for the oxidation degree. The method for measuring the oxidation degree of the surface of the stripping material according to the embodiment of the present invention includes a step of irradiating the surface of the stripping material with a laser and performing a mapping process on the Raman spectrum, and a step of deriving the oxidation degree of the surface of the stripping material based on the peak area of the Cu 2 O peak in the plurality of Raman spectra obtained by the mapping process.

[0026] Here, the mapping process is a process of repeating the measurement while scanning the measurement points (laser irradiation points) within a predetermined measurement region on the surface of the measurement object. The mapping image, which is two-dimensional measurement data obtained by the mapping process, contains the Cu 2Data on the peak area of the O peak is available for each pixel. In the Raman scattering measurement according to this embodiment, the spot diameter of the laser irradiated on the surface of the peeling material is, for example, 0.4 to 2.2 μm.

[0027] Cu included in the Raman spectrum 2 Since the peak area of the O peak changes according to the amount of oxide on the surface of the peeling material, Cu 2 The peak area of the O peak serves as an evaluation material for the degree of oxidation of the surface of the peeling material.

[0028] Figure 3(a) is an optical microscope image of the surface of the peeling material. The rectangular frame included in this optical microscope image indicates the measurement range of the Raman scattering measurement. Figure 3(b) shows a mapping image obtained by Raman scattering measurement in the measurement range shown in Figure 3(a). The size of the measurement range shown in Figure 3(a) and the mapping image shown in Figure 3(b) is 88 × 60 μm, and the size of one pixel of the mapping image is 2 μm × 2 μm. Each pixel of the mapping image contains data on the intensity of the peak (Cu 2 O vibration mode 2E u attributed to the lattice vibration of (Cu 2 O peak).

[0029] Figure 4 is an example of a Raman spectrum obtained by Raman scattering measurement of the surface of the peeling material performed under the above conditions, and shows two Raman spectra measured at the measurement points (the central points of the crosses) indicated by "1" and "2" included in the optical microscope image shown in Figure 3(a). This Raman spectrum contains a Cu 2 O peak. Each pixel of the mapping image shown in Figure 3(b) has a color density corresponding to the intensity of the Cu 2 O peak measured at that pixel.

[0030] Cu 2 The O peak is in the vicinity of 220 cm -1 in the Raman spectrum, 190 cm -1 or more, 250 cm -1Take the maximum intensity within the following range. The wavenumbers at which the maximum intensities of the respective peaks included in the Raman spectrum can shift depending on the environmental temperature during measurement, etc., but since the magnitude relationship of the wavenumbers at which these peaks take the maximum intensities does not change, there is no misidentification.

[0031] Cu according to this embodiment 2 The peak area of the Cu 2 O peak is calculated using the Covell method. The range of wavenumbers for measuring the peak area of the Cu 2 O peak is set manually at the valley values around the peak. In this embodiment, for the position where the Cu -1 O peak takes the maximum intensity, it is set to ±11.9 cm 2 The range of wavenumbers for measuring the peak area of the Cu 2 O peak is set first once in the measurement within the measurement range of 88 × 60 μm as shown in Fig. 3(a). Also, as the analysis software for measuring the peak area of the Cu

[0032] For example, in the Raman spectrum illustrated in Fig. 4, the peak area of the Cu 2 O peak is 96.3 (upper Raman spectrum) and 49.4 (lower Raman spectrum).

[0033] After obtaining the peak area of the Cu 2 O peak in each pixel of the mapping image, a histogram is created with the horizontal axis being the 256 classes obtained by dividing the range from the minimum value to the maximum value of the peak area of the Cu 2 O peak in each pixel of the mapping image, and the vertical axis being the frequency which is the number of pixels for each class. Then, the average value of the peak area of the peak is obtained from the created histogram and this is acquired as the oxidation degree. Fig. 5 shows a histogram of the mapping image including the Raman spectrum of Fig. 4 as an example of the histogram.

[0034] (Evaluation of the stripping material) The following shows the results of the evaluation of the degree of oxidation of the stripping material by experiments.

[0035] First, as the first evaluation, the relationship between the degree of oxidation of the surface of the stripping material and the oxidation state determined from the discoloration of the surface was evaluated. In this evaluation, for the stripping material mainly composed of copper stored under various storage conditions (temperature of 10 to 45 °C, humidity of 50 to 95% RH, time of 4 to 48 hours), the measurement of the degree of oxidation by the above method and the determination of the presence or absence of discoloration by observing the appearance were carried out. In this evaluation, a stripping material with a diameter of 6.3 mm and a length of about 5 cm was used and stored in a thermo-hygrostat.

[0036] The following Table 1 shows the numerical values of the degree of oxidation (average peak area of the Cu 2 O peak) of the stripping material obtained by experiments for each storage condition. Also, for those in which surface discoloration was visually confirmed, "(discoloration)" was entered below the numerical value of the degree of oxidation.

[0037] [Table 1]

[0038] Figure 6 is a graph plotting the data in Table 1 with the horizontal axis being the storage time (h) of the stripping material and the vertical axis being the degree of oxidation. According to the results shown in Table 1 and Figure 6, it can be seen that when the degree of oxidation is less than approximately 25, the oxidation of the surface of the stripping material is suppressed, and when stored under the conditions of a temperature of 40 °C or less, a humidity of 95% RH or less, and a time of 48 hours or less, the oxidation of the surface of the stripping material is suppressed.

[0039] Note that the stripping material shown in Figure 1(a) is the stripping material included in Table 1 and stored under the conditions of a temperature of 40 °C, a humidity of 95% RH, and a time of 12 hours. Also, the stripping material shown in Figure 1(b) is the stripping material included in Table 1 and stored under the conditions of a temperature of 45 °C, a humidity of 95% RH, and a time of 24 hours.

[0040] Next, as the second evaluation, the relationship between the degree of oxidation of the surface of the stripping material, the oxidation state determined from the discoloration of the surface, and the wear mass during wire drawing of the stripping material was evaluated. In this evaluation, for stripping materials mainly composed of copper stored under various storage conditions (temperature of 50°C, humidity of 10 - 22%RH, time of 48 hours - 3 weeks), the measurement of the degree of oxidation by the above method, the determination of the presence or absence of discoloration by observing the appearance, and the measurement of the mass of the wear powder after wire drawing were performed.

[0041] In this evaluation, a stripping material with a diameter of 6.3 mm and a length of about 9 m was used, and it was stored in a thermostatic chamber in a state where it was wound with a winding diameter of 1.09 m. In the measurement of the degree of oxidation, the stripping material was cut out to a length of about 5 cm, and Raman scattering mapping processing was performed. In wire drawing, a stripping material with a length of about 9 m was attached to a single-head wire drawing machine and wire drawn using a wire drawing die with a die hole diameter of 5.33 mm. After wire drawing the stripping material, the wear powder of the stripping material adhering to the die was removed using ethanol and tweezers, dried at 45°C for 24 hours to evaporate the ethanol, and then the mass of the wear powder was measured using an electronic balance. This mass measurement was performed 3 times, and the average value of the obtained measurement values was taken as the wear mass (mg / 9 m) during wire drawing of the stripping material.

[0042] The following Table 2 shows the storage conditions of the four stripping materials (designated as Samples A - D) for which this evaluation was performed, the numerical values of the degree of oxidation (average peak area of the Cu 2 O peak), the presence or absence of surface discoloration determined visually, and the wear mass during wire drawing. Note that "no storage" for the storage conditions of Sample A means that Sample A is a stripping material immediately after the oxide film has been peeled off and has not been stored in a thermostatic chamber. Also, the reason for the variation in the storage humidity of Samples B - D within the range of 10 - 22%RH is due to the humidity variation for each location in the large thermostatic chamber.

[0043]

Table 2

[0044] According to the results shown in Table 2, in Sample D which should originally have more oxidation progress than Sample C based on the storage conditions, the oxidation is suppressed compared to Sample C. This is presumably because Samples B - C were stored in a large thermostatic chamber with significant humidity variation by location, so the humidity around the parts where the actual oxidation degree was measured and discoloration was observed varied between Samples B - C. Therefore, among the results included in Table 2, regarding the relationship between the storage conditions and the evaluation results (oxidation degree, presence or absence of discoloration, wear mass during wire drawing) for Samples B - D, it was determined that the reliability is low and it cannot be used as an evaluation material.

[0045] On the other hand, according to the relationship between the oxidation degree, presence or absence of discoloration, and wear mass during wire drawing for Samples A - D, in Samples A, B, and D where the oxidation degree is less than 25, the surface oxidation is suppressed, and also, the wear during wire drawing is less and the amount of generated wear powder is small. If the amount of generated wear powder is small, it is possible to suppress the appearance defect of the enameled wire caused by the microbubbles entrapped in the wear powder attached to the surface of the skin - peeling material foaming during the firing after enamel coating.

[0046] (Manufacture of enameled wire) According to the present embodiment, an enameled wire can be manufactured using a rough - drawn wire such as a skin - peeling material whose oxidation degree is evaluated using the above - mentioned evaluation method.

[0047] That is, according to the present embodiment, a mapping process step of irradiating a laser on the surface of a rough - drawn wire whose main component is copper and performing mapping processing on the Raman spectrum, and Cu contained in each pixel of the mapping image obtained by the mapping process 2 The vibration mode 2E of O u An evaluation step of creating a histogram of the peak areas of the peaks attributed to the lattice vibration and evaluating the oxidation degree of the surface of the rough - drawn wire using the average value of the peak areas of the peaks obtained from the histogram, a wire - drawing step of wire - drawing the rough - drawn wire after the evaluation step, and a film - forming step of applying an enamel paint to the surface of the conductor formed by wire - drawing the rough - drawn wire after the wire - drawing step and firing to form an insulating film around the conductor, thereby providing a method for manufacturing an enameled wire.

[0048] In this method for manufacturing enameled wire, the wire drawing process and the film forming process are carried out when a predetermined result is obtained in the evaluation process. For example, as described above, since it is preferable that the degree of oxidation of the surface of the rough drawn wire is less than 25, when the result that the degree of oxidation of the surface of the rough drawn wire is less than 25 is obtained in the evaluation process, the wire drawing process and the film forming process are carried out.

[0049] That is, for example, the mapping process in the mapping process is carried out using a Raman measurement device (RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton), the laser wavelength is 532.06 nm, the width of the incident slit of the spectroscope is 50 μm, the ratio of the light quantity after attenuation to the maximum light quantity of the laser of the ND filter (attenuation ratio) is 215 / 255, the number of rulings of the diffraction grating is 600 gr / mm, the magnification and numerical aperture (NA) of the objective lens are 100 times and 0.9 respectively, and the mapping range and pixel size are 88×60 μm and 2×2 μm respectively. When the histogram created in the evaluation process has the horizontal axis divided into 256 classes in the range from the minimum value to the maximum value of the peak area of the peak, and the number of pixels for each class on the vertical axis, in the evaluation process, when the average value of the peak area of the peak obtained from the histogram is less than 25, the wire drawing process and the film forming process are carried out.

[0050] In addition, for the wire drawing of the rough drawn wire in the wire drawing process and the formation of the insulating film in the film forming process, the techniques used in the conventional general method for manufacturing enameled wire can be used. Further, in addition to the wire drawing process, a rolling process for performing rolling to process the round rough drawn wire into a rectangular wire may be carried out.

[0051] (Effects of the Embodiment) According to the embodiment of the present invention, by using the mapping process of Raman scattering, the storage conditions of rough drawing wires such as stripping materials that can suppress surface oxidation are clarified, appropriate storage conditions are set, or the degree of surface oxidation is measured to select rough drawing wires with suppressed oxidation. As a result, it is possible to provide a rough drawing wire with suppressed surface oxidation that can form a high-quality enameled wire, and an enameled wire formed using the rough drawing wire.

[0052] (Summary of the embodiment) Next, the technical idea grasped from the embodiments described above will be described by referring to the reference numerals and the like in the embodiments. However, each reference numeral and the like in the following description are not limited to the members and the like that specifically show the components in the claims in the embodiments.

[0053] [1] A rough drawing wire mainly composed of copper, wherein the degree of oxidation measured by Raman spectroscopic analysis of the surface of the rough drawing wire is less than 25. The measurement of the degree of oxidation is performed by performing Raman spectrum mapping processing under the following conditions, creating a histogram from the peak areas of the Raman spectrum peaks in each pixel of the obtained mapping image, obtaining the average value of the plurality of peak areas from the histogram, and measuring the average value as the degree of oxidation. The plurality of Raman spectrum peaks are peaks attributed to the lattice vibration of the vibration mode 2E of Cu 2 O, and the histogram has a horizontal axis divided into 256 classes in the range from the minimum value to the maximum value of the plurality of peak areas, and a vertical axis representing the frequency, which is the number of pixels for each class, of the rough drawing wire (1). u is a peak attributed to the lattice vibration of, and the histogram has a horizontal axis divided into 256 classes in the range from the minimum value to the maximum value of the plurality of peak areas, and a vertical axis representing the frequency, which is the number of pixels for each class, of the rough drawing wire (1). Raman measurement device: RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton Laser wavelength: 532.06 nm Width of the entrance slit of the spectroscope: 50 μm Ratio of the light amount after attenuation to the maximum light amount of the laser of the ND filter (attenuation ratio): 215 / 255 Number of rulings of the diffraction grating: 600 gr / mm Magnification of the objective lens: 100x Numerical aperture (NA): 0.9 Mapping range: 88×60μm Pixel size: 2×2μm

[0054] [2]An enameled wire (100) comprising a conductor (10) formed by drawing the rough drawn wire (1) described in [1] above, and an insulating coating (11) provided around the conductor (10).

[0055] [3]A drawing process of drawing the rough drawn wire (1) described in [1] above, and after the drawing process, an enamel paint is applied to the surface of the conductor (10) formed by drawing the rough drawn wire (1), and fired to form an insulating coating (11) around the conductor (10). A method for manufacturing an enameled wire (100), including a film forming process.

[0056] [4]A mapping process of irradiating a laser on the surface of the rough drawn wire (1) whose main component is copper and performing mapping processing on the Raman spectrum, and Cu contained in each pixel of the mapping image obtained by the mapping processing 2 The vibration mode 2E of O u A histogram of the peak areas of the peaks attributed to the lattice vibrations of is created, and the degree of oxidation of the surface of the rough drawn wire (1) is evaluated using the average value of the peak areas obtained from the histogram. After the evaluation process, a drawing process of drawing the rough drawn wire (1), and after the drawing process, an enamel paint is applied to the surface of the conductor (10) formed by drawing the rough drawn wire (1), and fired to form an insulating coating (11) around the conductor (10). A method for manufacturing an enameled wire (100), including a film forming process, wherein the drawing process and the film forming process are performed when a predetermined result is obtained in the evaluation process.

[0057] [5] The mapping process in the mapping process step is performed using a Raman measurement device (RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton), with a laser wavelength of 532.06 nm, an incident slit width of the spectroscope of 50 μm, a ratio of the light intensity after attenuation to the maximum light intensity of the laser of the ND filter (attenuation ratio) of 215 / 255, a grating density of the diffraction grating of 600 gr / mm, a magnification and numerical aperture (NA) of the objective lens of 100 times and 0.9 respectively, a mapping range and pixel size of 88×60 μm and 2×2 μm respectively. The histogram created in the evaluation step has the horizontal axis divided into 256 classes in the range from the minimum value to the maximum value of the peak area, and the vertical axis represents the frequency, which is the number of pixels for each class. In the evaluation step, when the average value of the peak area obtained from the histogram is less than 25, the wire drawing step and the film forming step are performed. The method for manufacturing the enamel wire (100) according to [4] above.

[0058] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Also, the above-described embodiments do not limit the invention according to the claims. It should also be noted that not all combinations of the features described in the embodiments are essential means for solving the problems of the invention.

Explanation of reference numerals

[0059] 100 Enamel wire 10 Conductor 11 Insulating film

Claims

1. A rough drawn wire having copper as a main component, wherein the degree of oxidation measured by Raman spectroscopic analysis of the surface of the rough drawn wire is less than 25, the measurement of the degree of oxidation is performed by performing mapping processing of a Raman spectrum under the following conditions, creating a histogram from the peak areas of the Raman spectrum peaks in each pixel of the obtained mapping image, obtaining an average value of the plurality of the peak areas from the histogram, and measuring the average value as the degree of oxidation, A plurality of the Raman spectrum peaks are Cu ２ The vibration mode 2E of O ｕ The peak is attributed to the lattice vibration of the histogram has a horizontal axis representing classes obtained by dividing the range from the minimum value to the maximum value of the plurality of the peak areas into 256, and a vertical axis representing the frequency which is the number of pixels for each class, Rough drawn wire. Raman measurement device: RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton Laser wavelength: 532.06 nm Width of the incident slit of the spectroscope: 50 μm Ratio of the light quantity after attenuation to the maximum light quantity of the laser by the ND filter (attenuation ratio): 215 / 255 Number of rulings of the diffraction grating: 600 gr / mm Magnification of the objective lens: 100 times Numerical aperture (NA): 0.9 Mapping range: 88×60 μm Pixel size: 2×2 μm

2. A conductor formed by drawing the rough drawn wire according to claim 1, and an insulating coating provided around the conductor, comprising Enameled wire.

3. A wire drawing step of drawing the rough drawn wire according to claim 1, and a coating forming step of applying an enamel paint to the surface of the conductor formed by drawing the rough drawn wire after the wire drawing step and baking it to form an insulating coating around the conductor, comprising a method for manufacturing an enameled wire.

4. A mapping processing step of irradiating a laser onto the surface of a rough drawn wire having copper as a main component and performing mapping processing of a Raman spectrum, Cu contained in each pixel of the mapping image obtained by the mapping process ２ The vibration mode 2E of O ｕ Create a histogram of the peak areas of the peaks attributed to the lattice vibrations of, and evaluate the degree of oxidation of the surface of the rough drawing line using the average value of the peak areas obtained from the histogram. An evaluation step a wire drawing step of drawing the rough drawn wire after the evaluation step, and a coating forming step of applying an enamel paint to the surface of the conductor formed by drawing the rough drawn wire after the wire drawing step and baking it to form an insulating coating around the conductor, comprising the wire drawing step and the coating forming step are performed when a predetermined result is obtained in the evaluation step, a method for manufacturing an enameled wire.

5. The mapping process in the mapping process step is carried out using a Raman measuring device (RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton), with a laser wavelength of 532.06 nm, an incident slit width of the spectroscope of 50 μm, a ratio of the light amount after attenuation to the maximum light amount of the laser of the ND filter (attenuation ratio) of 215 / 255, a grating constant of the diffraction grating of 600 gr / mm, a magnification and numerical aperture (NA) of the objective lens of 100 times and 0.9 respectively, and a mapping range and pixel size of 88×60 μm and 2×2 μm respectively. The histogram created in the evaluation step has a horizontal axis with 256 classes divided in the range from the minimum value to the maximum value of the peak area, and a vertical axis with the frequency, which is the number of pixels for each class. In the evaluation step, when the average value of the peak area obtained from the histogram is less than 25, the wire drawing step and the film forming step are carried out. The method for manufacturing an enameled wire according to claim 4.

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