DIAGNOSTIC DEVICE AND DIAGNOSTIC PROCEDURES

Abstract

A diagnostic device (10) for diagnosing the cause of streaks produced on the surface of a workpiece on which a mirror surface machining has been performed by a machine tool (12) by moving a tool mounted on a spindle relative to the workpiece, the diagnostic device comprising: a spindle rotation frequency detection unit (26) configured to determine a spindle rotation frequency (Fm) of the spindle, a distance detection unit (28) configured to determine a distance (D) of the streaks produced on the surface of the workpiece, a feed rate detection unit (30) configured to determine a feed rate (V) of the tool when the mirror surface machining is performed on the surface of the workpiece, a streak frequency calculator (32) configured to determine a streak frequency that is a cause of the streaks,a trigger frequency calculator (34) designed to calculate a trigger frequency that causes vibrations at the strip frequency (Fp) based on the spindle rotational frequency (Fm) and the strip frequency (Fp), and a notification unit (24) designed to indicate whether or not there is a peripheral device in the vicinity of the machine tool (12) that generates vibrations at the trigger frequency (Fc).

Description

Background of the invention; Field of the invention

[0001] The present invention relates to a diagnostic device and a diagnostic method for diagnosing the cause of streaks appearing on the surface of a machined object or workpiece that has been subjected to mirror surface machining with a machine tool. Description of the state of the art

[0002] In recent times, the development and advancement of tools and machine tools in the field of surface machining (machined surface) of workpieces has led to high-quality machined surfaces, making it possible to achieve surfaces close to a mirror finish. However, vibrations from peripheral equipment surrounding the machine tool can cause streaks to appear on the machined surface after the mirror-like surface machining process.

[0003] As a conventional method for machining an object to be machined with a machine tool, Japanese patent disclosure no. 2013-000850 describes a technology for avoiding chatter vibrations during the machining of a workpiece by detecting the frequencies of the chatter vibrations that occur during machining, estimating the natural frequency of the spindle in its rotating state based on the detected frequencies of chatter vibrations and the rotational frequency of the spindle of the machine tool, and changing the spindle rotational frequency based on the estimated natural frequency. Summary of the invention

[0004] However, Japanese patent publication no. 2013-000850 does not propose anything to specify or determine the frequencies of the peripheral devices that cause such stripes.

[0005] It is therefore an object of the present invention to propose a diagnostic device and a diagnostic method for displaying or notifying about the frequencies of the peripheral devices that cause stripes on the surface of a workpiece during mirror surface machining in a machine tool.

[0006] According to a first aspect of the present invention, a diagnostic device for diagnosing the cause of streaks generated on the surface of a workpiece, on which a mirror surface machining operation has been performed using a machine tool by moving a tool mounted on a spindle relative to the workpiece, comprises a spindle rotation frequency detection unit configured to determine the spindle rotation frequency, a distance detection unit configured to detect the distance (pitch) of the streaks generated on the surface of the workpiece, a feed rate detection unit configured to detect the feed rate (feed speed) of the tool when the mirror surface machining operation is performed on the surface of the workpiece, and a streak frequency calculator configured to determine a streak frequency that is a cause of the streaks.to calculate, based on the spacing of the strips and the feed rate of the tool, a trigger frequency calculator designed to calculate a trigger frequency that causes vibrations of the strip frequency based on the spindle rotation frequency and the strip frequency, and a notification unit designed to indicate whether or not there is a peripheral device that causes vibrations at the trigger frequency in the vicinity of the machine tool.

[0007] According to a second aspect of the present invention, a method for diagnosing the cause of streaks generated on the surface of a workpiece on which a mirror surface machining has been performed by a machine tool by moving a tool mounted on a spindle relative to the workpiece comprises a first step in which a spindle rotation frequency is detected via a spindle rotation frequency detection unit, a second step in which a distance detection unit detects a distance (pitch) of the streaks generated on the surface of the workpiece, a third step in which a feed rate detection unit detects a feed rate (insertion rate) of the tool when mirror surface machining is performed on the surface of the workpiece, and a fourth stepin which a strip frequency calculator uses the spacing of the strips and the feed rate of the tool to calculate a strip frequency that is the cause of the strips, in a fifth step in which a trigger frequency calculator uses the spindle rotation frequency and the spacing frequency to calculate a trigger frequency that causes vibrations at the strip frequency, and in a sixth step in which a notification unit indicates whether or not there is a peripheral device in the vicinity of the machine tool that generates vibrations at the trigger frequency.

[0008] The present invention makes it possible to communicate the frequency of a peripheral device that could cause streaks to appear on the workpiece surface when the machine tool performs mirror surface machining. This allows for countermeasures to be taken against the vibrations on the peripheral device. As a result, mirror surface machining can be carried out precisely, preventing the appearance of streaks on the workpiece surface during subsequent processes.

[0009] The above and further tasks, features and advantages of the present invention will become even clearer from the following description in conjunction with the accompanying drawings, in which a preferred embodiment of the invention is illustrated by way of example. List of characters Fig. 1 is a block diagram of a machining system with a diagnostic device according to the present invention. Fig. 2 is a flowchart that shows a workflow (diagnostic procedure) of the diagnostic device according to Fig. 1 before the mirror surface processing shows, Fig. Figure 3 is a flowchart that illustrates the workflow (diagnostic procedure) of the diagnostic device according to Fig. 1 after the mirror surface processing shows, and Fig. Figure 4 is a diagram showing an example of a measurement result for the surface roughness of the workpiece surface. Description of preferred embodiments

[0010] A diagnostic device and a diagnostic method according to the present invention are below explained in detail by describing a preferred embodiment with reference to the accompanying drawings. [Configuration of the present embodiment (Explanation of the diagnostic device 10)]

[0011] As shown in Fig-1, a diagnostic device is used. 10 according to the present embodiment on a machining system 16 appropriate, that a machine tool 12 and a numerical control device 14 exhibits, and identifies (diagnoses) the cause of streaks that appear on the surface (machined surface) of a workpiece machined by the machine tool 12 to be trained in the workpiece to be processed.

[0012] The processing system 16 The diagnostic device includes 10 , the machine tool 12 , the numerical control device 14 , a temperature sensor (spindle temperature measuring unit) 18 and a surface roughness measuring unit 20 The numerical control device 14 controls the machine tool 12 so that it performs a predetermined operation on a workpiece and delivers the data to the diagnostic device. 10Information about the machining conditions of the machine tool 12 For the workpiece, e.g., the feed rate (feed rate) V of the tool, the number of cutting teeth Cn of the tool, the spindle rotational frequency Fm of the spindle, etc. The machine tool 12 The machine tool includes a spindle (not shown), a tool attached to the spindle, and the like. 12 performs a mirror surface machining on the surface (machined surface) of a workpiece by moving the tool and the workpiece relative to each other.

[0013] The temperature sensor 18 It measures the temperature Tc of the spindle and sends a detection signal to the diagnostic device. 10 from which the measured spindle temperature Tc is indicated. The measuring unit 20 For surface roughness, it measures the surface roughness of the workpiece surface after mirror surface processing and transmits it to the diagnostic device.10 It outputs a detection signal indicating the measured surface roughness. The temperature sensor 18 and the surface roughness measuring unit 20 components of the diagnostic device 10 or from the diagnostic device 10 separate devices.

[0014] The diagnostic device 10 includes a diagnostic unit 22 for diagnosing the cause of the streaks produced on the surface of a workpiece based on various pieces of information provided by the numerical control device 14 , the temperature sensor 18 and the surface roughness measuring unit 20 be supplied, and a notification unit 24 to display or output a message about the diagnostic result from the diagnostic unit 22 outwards. The diagnostic unit 22 includes a spindle rotation frequency detection unit 26 , a distance detection unit28 , a feed rate detection unit 30 , a strip frequency calculator 32 , a trigger frequency calculator 34 , a storage unit 36 , a tooth counting unit 37 , a tool vibration frequency calculator 38 and a unit of determination or specification 40 .

[0015] The spindle rotation frequency detection unit 26 The spindle rotational frequency Fm of the spindle, which is determined by the numerical control device, is recorded. 14 is supplied. The distance detection unit 28 measures the distance (pitch) D the stripes that appear on the surface of the workpiece, based on the surface roughness measuring unit 20 measured surface roughness. The feed rate detection unit 30It records the feed rate (feed rate) V of the tool during mirror surface machining, which is determined by the numerical control device. 14 is supplied.

[0016] The strip frequency calculator 32 calculates a stripe frequency Fp of the stripes based on the distance. D , which is from the distance detection unit 28 was recorded, and the feed rate V, which is measured by the feed rate detection unit 30 was recorded. Specifically, the stripe frequency calculator calculates 32 The stripe frequency Fp is determined using the following reference equation: Fp [Hz] = V [mm / s] / D [mm].

[0017] The trigger frequency calculator 34 It calculates a trigger frequency Fc, which causes the strip frequency Fp, based on the spindle rotation frequency Fm, which is determined by the spindle rotation frequency detection unit. 26was recorded, and the stripe frequency Fp, which was determined by the stripe frequency calculator 32 The calculation was performed. The specific calculation method will be described later.

[0018] The storage unit 36 The natural vibration frequency Fe of the spindle is stored according to the temperature Tc or the spindle temperature. For example, it is possible to measure the natural vibration frequency Fe of the spindle by recording the spindle's acceleration using an accelerometer (such as a laser Doppler accelerometer) when a vibration is applied to the spindle by a vibrator (not shown). In this case, the natural vibration frequency Fe of the spindle at temperature Tc can be stored in the memory unit at the time of transport from the factory. 36 The data will be stored. Note that the storage unit also serves as a buffer for the diagnostic device. 10It can be used to store other information.

[0019] The tooth counting unit 37 The number of cutting teeth Cn of the tool is derived from the numerical control device. 14 The tool vibration frequency calculator 38 Based on the spindle rotational frequency Fm and the number of cutting teeth Cn of the tool, the tool vibration frequency Ft is calculated, which is the frequency at which the tool vibrates when the spindle rotates. Specifically, the tool vibration frequency calculator calculates... 38 The tool vibration frequency Ft can be determined using the following reference equation: Ft [ Hz ] = Fm [ Hz ] × Cn

[0020] The unit of determination 40 obtains from the storage unit 36 The vibration natural frequency Fe corresponds to the spindle temperature Tc, which is determined by the temperature sensor. 18The system measures the vibration natural frequency (Fe) and determines whether the absolute value of the difference between the measured vibration natural frequency (Fe) and the tool vibration frequency (Ft) is less than or equal to a threshold value (TH). In this case, for example, the threshold value (TH) is defined as a difference between the vibration natural frequency (Fe) and a specified fraction of the vibration natural frequency (Fe) (e.g., Fe / 1.5). In other words, the threshold value (TH) can depend on the vibration natural frequency (Fe).

[0021] The notification unit 24 is a notification device, for example a display, a speaker, a lamp or the like, that directly displays the diagnostic result from the diagnostic unit 22 an output device that displays the diagnostic result externally, or an output device that indirectly indicates the diagnostic result externally by sending the diagnostic result to a non-displayed display unit or the like of the numerical control device. 14is output by the notification unit. 24 The notified diagnostic result includes information indicating whether it is in the vicinity of the machine tool. 12 a peripheral device that detects vibrations during the triggering frequency calculation by the trigger frequency computer 34 calculated trigger frequency Fc generates, gives or does not produce, and information indicating that the reason for the occurrence of stripes lies in vibrations of the tool vibration frequency Ft, i.e. that the stripes are caused by the tool vibration when the determining unit 40 determines that the absolute value is equal to or less than the threshold value TH. [Operating mode of the embodiment (explanation of the diagnostic procedure)]

[0022] Next, the operating mode (diagnostic procedure) of the diagnostic device will be described. 10 according to the present embodiment with reference to the Fig. 2 to Fig. 4 described. This involves a diagnostic procedure that is carried out on the surface of a workpiece before the mirror surface processing (see ). Fig. 2), and a diagnostic procedure that is carried out after the mirror surface treatment (see Fig. 3), described. When explaining the workflow, reference will also be made to, if necessary, Fig. 1 taken.

[0023] First, the diagnostic procedure is performed before the mirror surface treatment with reference to Fig. 2 explained. In step S1 The spindle rotation frequency detection unit determines 26 (cf.) Fig. 1) the spindle rotational frequency Fm. In the description of Fig. 2. It is assumed that the spindle rotation frequency Fm is 200 [Hz].

[0024] Next determined in step S2 the tooth counting unit 37 The number of cutting teeth Cn of the tool. In explaining Fig. 2. It is assumed that the number of incisors Cn is equal to 2.

[0025] Next calculated in step S3 the tool vibration frequency calculator 38 the tool vibration frequency Ft of the tool, which is associated with the rotation of the spindle, based on the value in step S1 determined spindle rotational frequency Fm and the one in step S2 The determined number of cutting teeth Cn of the tool. Since in the explanation of Fig. If 2 Fm = 200 [Hz] and Cn = 2, then the tool vibration frequency Ft is 400 [Hz] (= 200 [Hz] x 2).

[0026] Next determined in step S4 the unit of determination 40 The vibration natural frequency Fe corresponds to the spindle temperature Tc, which is determined by the temperature sensor. 18 was recorded from the storage unit 36 . In explaining Fig. 2. It is assumed that the natural frequency of the vibration Fe is 400 [Hz].

[0027] Next, determine in step S5 the unit of determination 40 , whether |Ft - Fe|, i.e. the absolute value of the difference between the tool vibration frequency Ft, which is in step S3 was calculated, and the vibration natural frequency Fe, which was calculated in step S4 was determined, is equal to or less than the threshold value TH. Since in the explanation of Fig. 2 Assuming that the threshold TH is at TH = Fe - Fe / 1.5, the threshold TH is approximately 166.67 [Hz] (= 500 - 500 / 1.5).

[0028] If it determines that the absolute value of the difference (|Ft - Fe|) is equal to or less than the threshold TH (step S5 (YES), determines the unit of determination 40 in step S5 that the current state will cause an anomaly, and the control system moves on to the next step. S6 If, on the other hand, in step S5It is determined that the absolute value of the difference (|Ft - Fe|) is not equal to or less than the threshold TH, i.e., if the absolute value is greater than the threshold TH, the unit of determination is determined. 40 that the current state is normal, and then the current work process is completed.

[0029] In step S6 notifies the notification unit 24 The user is informed that striping is caused by the tool vibration frequency Ft. Upon receiving this information, the user can recognize that the tool vibration frequency Ft is the cause of the striping and can change the tool vibration frequency Ft by changing the spindle speed Fm and / or the number of cutting teeth Cn.

[0030] Next, with reference to Fig. 3 describes the diagnostic procedure after the mirror surface treatment. In step S10(first step) determines the spindle rotation frequency detection unit 26 The spindle rotational frequency Fm during mirror surface machining. In the description of Fig. 3. It is assumed that the spindle rotational frequency Fm 200 [Hz] is-

[0031] Next, the distance detection unit determines 28 in step S11 (second step) the distance (pitch) D of the stripes that appear on the workpiece surface, based on the surface roughness measuring unit 20 measured surface roughness. In explaining Fig. 3. It is assumed that the distance D between the strips is 0.2 [mm]. Fig. Figure 4 shows an example of the surface roughness measurement result obtained by the surface roughness measuring unit. 20 was measured. Fig. 4 The horizontal axis represents the distance along the surface of the workpiece and the vertical axis represents the difference in the height of the surface relative to a reference value ( 0 Furthermore, the distance detection unit can determine the distance D between the strips based on the surface roughness parameters from the measurements taken by the surface roughness measuring unit. 20 for example, calculate the mean width of the roughness profile elements Rsm, the mean width of the primary profile elements Psm, or the mean width of the wave profile elements Wsm.

[0032] Next determined in step S12 (third step) the feed rate detection unit 30 The feed rate (feed rate) V of the tool during mirror surface machining. In describing Fig. 3. The feed rate V is set to 8 [mm / s].

[0033] Next used in S13(fourth step) of the strip frequency calculator 32 the distance D , which in step S11 through the distance detection unit 28 was determined, and the feed rate V, which is in step S12 through the feed rate detection unit 30 was determined in order to calculate the fringe frequency Fp, which causes the fringe. Since in the explanation of Fig. Given that D = 0.2 [mm] and V = 8 [mm / s], the fringe frequency is Fp. 40 [Hz] = 8 [mm / s] / 0.2 [mm]).

[0034] Then used in step S14 (fifth step) the trigger frequency calculator 34 the spindle rotation frequency Fm, which is in step S10 from the spindle rotation frequency detection unit 26 was determined, and the stripe frequency Fp, which is in step S13 through the strip frequency calculator 32was calculated to determine the trigger frequency Fc, which is the reason for the generation of the stripe frequency Fp.

[0035] In this case, the trigger frequency calculator calculates 34 two trigger frequencies Fc, one obtained by adding the strip frequency Fp to the spindle rotation frequency Fm, and the other obtained by subtracting the strip frequency Fp from the spindle rotation frequency Fm.

[0036] Specifically, the trigger frequencies Fc are calculated according to the following reference equations: Fc = fm + Fp and Fc = Fm - Fp. Since the explanation of Fig. If Fm = 200 Hz and Fp = 40 Hz, the trigger frequencies Fc are 240 [Hz] (= 200 + 40) and 160 [Hz] (= 200 - 40).

[0037] Alternatively, the trigger frequency calculator calculates 34Trigger frequencies Fc are determined by adding the strip frequency Fp to the spindle rotation frequency Fm N times or 1 / N times, or by subtracting the strip frequency Fp from the spindle rotation frequency Fm N times or 1 / N times. Here, N is an integer greater than or equal to 2. Specifically, the trigger frequencies Fc are calculated using the following reference equations: Fc = Fm + N x Fp and Fc = Fm - N x Fp, or Fc = Fm + (1 / N) x Fp and Fc = Fm - (1 / N) x Fp.

[0038] Finally, notified in step S15 (sixth step) the notification unit 24 informs the user of a diagnostic result that includes the trigger frequencies Fc ( 240 [Hz] and 160 [Hz]) includes, i.e., the notification unit 24 asks the user if it is in the vicinity of the machine tool 12A peripheral device exists that generates vibrations at the trigger frequencies Fc. As a result, the user checks, based on the notified diagnostic result, whether there is a problem in the vicinity of the machine tool. 12 There is a peripheral device that may or may not generate vibrations at the trigger frequencies Fc. If such a peripheral device is found, the user can take appropriate action on the device to prevent the vibrations. Accordingly, it is possible to perform mirror surface processing more accurately in the next and subsequent processes, preventing the appearance of streaks. [Technical concepts resulting from the design]

[0039] The following describes technical concepts or ideas that result from the embodiment described above.

[0040] The diagnostic device ( 10) for diagnosing the cause of streaks produced on the surface of a workpiece machined by the machine tool ( 12 ) a mirror surface machining was carried out by moving the tool attached to the spindle relative to the workpiece, the spindle rotation frequency detection unit includes ( 26 ), which is designed to determine the spindle rotational frequency (Fm) of the spindle, the distance detection unit ( 28 ), which is designed to maintain the distance ( D ) to determine the stripes generated on the surface of the workpiece, the feed rate detection unit ( 30 ), which is designed to detect the feed rate (V) of the tool when mirror surface machining is performed on the surface of the workpiece, the strip frequency calculator ( 32 ), which is designed to determine the fringe frequency (Fp), which is one cause of the fringes, based on the distance (D ) the strip and the feed rate (V) of the tool, the trigger frequency calculator ( 34 ), which is designed to calculate the trigger frequency (Fc), which causes the strip frequency (Fp) to vibrate, from the spindle rotation frequency (Fm) and the strip frequency (Fp), and the notification unit ( 24 ), which is designed to indicate whether there is a danger in the vicinity of the machine tool ( 12 ) a peripheral device that generates vibrations at the trigger frequency (Fc), or not.

[0041] The configuration described above makes it possible to notify the user about the frequency of a peripheral device that is the cause of the streaks appearing on the surface of the workpiece when the machine tool ( 12) performs mirror surface machining. This makes it possible to implement an anti-vibration measure on the peripheral device and thus perform mirror surface machining precisely, preventing the occurrence of streaks on the workpiece surface during subsequent processes.

[0042] The trigger frequency calculator ( 34 The trigger frequencies (Fc) can be calculated by adding the stripe frequency (Fp) to the spindle rotation frequency (Fm) or by subtracting the stripe frequency (Fp) from the spindle rotation frequency (Fm). This allows for precise information about the cause of the stripe appearance.

[0043] The trigger frequency calculator ( 34The trigger frequencies (Fc) can be calculated by adding the stripe frequency (Fp) to the spindle rotation frequency (Fm) N times or 1 / N times, or by subtracting the stripe frequency (Fp) from the spindle rotation frequency (Fm) N times or 1 / N times. In this case as well, it is possible to inform the user precisely about the cause of the stripe occurrence.

[0044] The diagnostic device ( 10 ) can also include the storage unit ( 36 ), which is designed to store the vibration natural frequency (Fe) of the spindle, the tool vibration frequency calculator ( 38 ), which is designed to calculate the tool vibration frequency (Ft) of the tool, which is associated with the rotation of the spindle, based on the spindle rotation frequency (Fm) and the number of cutting teeth (Cn) of the tool, and the unit of determination ( 40), which is designed to determine whether the absolute value (|Ft - Fe |) of the difference between the vibration natural frequency (Fe) and the tool vibration frequency (Ft) is equal to or less than a threshold value (TH) or not, and the notification unit ( 24 ) can then, if the unit of determination ( 40 If the absolute value (|Ft - Fe|) is equal to or less than the threshold value (TH), the system indicates that the fringing is caused by vibrations at the tool vibration frequency (Ft). This configuration makes it possible to inform the user of the risk of fringing due to tool vibration before mirror surface machining is performed on the workpiece surface. By modifying the machining conditions during mirror surface machining or similar operations, it is possible to perform mirror surface machining while preventing fringing.

[0045] The diagnostic device ( 10 ) can also be used to measure the spindle temperature ( 18 ) which is designed to measure the spindle temperature (Tc), and the storage unit ( 36 ) can store the vibration natural frequency (Fe) associated with the spindle temperature (Tc), and the unit of determination ( 40 It can determine whether the absolute value (|Ft - Fe|) of the difference between the vibration natural frequency (Fe), which is associated with the spindle temperature (Tc), and the tool vibration frequency (Ft) is equal to or less than the threshold value (TH). This makes it possible to accurately determine whether or not there is a risk of stripping occurring due to tool vibration, taking the spindle temperature (Tc) into account.

[0046] The distance detection unit ( 28) can determine the spacing of the stripes based on the surface roughness of the workpiece surface, which is measured by the surface roughness measuring unit ( 20 ) is measured. This makes it possible to precisely identify the cause of the streaks.

[0047] The distance detection unit ( 28 ) can increase the distance ( D ) the strip based on the surface roughness parameters as the measurement result of the surface roughness measuring unit ( 20 ) calculate. In this case, too, it is possible to precisely identify the reason for the formation of stripes.

[0048] A method for diagnosing the cause of streaks produced on the surface of a workpiece machined by a machine tool ( 12 ) a mirror surface machining was carried out by moving the tool attached to the spindle relative to the workpiece, includes a first step ( S10), in which the spindle rotation frequency detection unit ( 26 ) the spindle rotational frequency (Fm) of the spindle is determined, a second step ( S11 ), in which the distance detection unit ( 28 ) the distance ( D ) the number of stripes produced on the surface of the workpiece is determined, a third step ( S12 ), in which the feed rate detection unit ( 30 ) the feed rate (V) of the tool is determined when the mirror surface machining is performed on the surface of the workpiece, a fourth step ( S13 ), in which the strip frequency calculator ( 32 ) based on the distance ( D ) the stripe frequency (Fp), which is one reason for the stripes, is calculated using the stripe frequency and the feed rate (V) of the tool, a fifth step ( S14 ), in which the trigger frequency calculator ( 34) the trigger frequency (Fc), which causes vibrations of the strip frequency (Fp), is calculated based on the spindle rotation frequency (Fm) and the strip frequency (Fp), and a sixth step ( S15 ), in which the notification unit ( 24 ) indicates whether there is a risk of developing problems in the vicinity of the machine tool ( 12 ) whether or not there is a peripheral device that generates vibrations at the trigger frequency (Fc).

[0049] In this case too, it is possible to inform the user about the frequency of a peripheral device that would be the reason for streaks appearing on the surface of the workpiece when the machine tool ( 12) performs mirror surface machining. This makes it possible to counteract vibrations on the peripheral device and thus perform mirror surface machining precisely, preventing the appearance of streaks on the workpiece surface during mirror surface machining in the next and subsequent processes.

Claims

[1] A diagnostic device (10) for diagnosing the cause of streaks produced on a surface of a workpiece on which a mirror surface machining has been carried out by a machine tool (12) by moving a tool attached to a spindle relative to the workpiece, the diagnostic device comprising: a spindle rotation frequency detection unit (26) designed to determine a spindle rotation frequency (Fm) of the spindle, a distance detection unit (28) designed to determine a distance (D) of the stripes produced on the surface of the workpiece, a feed rate detection unit (30) designed to determine a feed rate (V) of the tool when mirror surface machining is performed on the surface of the workpiece, a stripe frequency calculator (32) designed to calculate a stripe frequency, which is a reason for the stripes, based on the distance (D) of the stripes and the feed rate (V) of the tool, a release frequency calculator (34) designed to calculate a release frequency that causes vibrations with the strip frequency (Fp) based on the spindle rotation frequency (Fm) and the strip frequency (Fp), and a notification unit (24) designed to indicate whether or not there is a peripheral device in the vicinity of the machine tool (12) that generates vibrations at the trigger frequency (Fc). [2] The diagnostic device (10) according to claim 1, wherein the trigger frequency calculator (34) is configured to calculate the trigger frequencies (Fc) by adding the strip frequency (Fp) to the spindle rotation frequency (Fm) or by subtracting the strip frequency (Fp) from the strip frequency (Fp). [3] The diagnostic device (10) according to claim 2, wherein the trigger frequency calculator (34) is configured to calculate the trigger frequencies (Fc) by adding the strip frequency (Fp) to the spindle rotation frequency (Fm) N times or 1 / N times and by subtracting the strip frequency (Fp) from the spindle rotation frequency (Fm) N times or 1 / N times, where N is an integer greater than or equal to 2. [4] The diagnostic device (10) according to any one of claims 1 to 3, further comprising: a storage unit (36) designed to store a vibration natural frequency (Fe) of the spindle, a tool vibration frequency calculator (38) designed to calculate a tool vibration frequency (Ft) of the tool, which is associated with the rotation of the spindle, based on the spindle rotation frequency (Fm) and a number of cutting teeth (Cn) of the tool, and a determination unit (40) designed to determine whether an absolute value (|Ft - Fe|) of the difference between the vibration natural frequency (Fe) and the tool vibration frequency (Ft) is equal to or less than a threshold value (TH), wherein the notification unit (24) is configured to indicate that the stripes are caused by vibrations at the tool vibration frequency (Ft) when the determination unit (40) determines that the absolute value (|Ft - Fe |) is equal to or less than the threshold value (TH). [5] The diagnostic device (10) according to claim 4, further comprising a spindle temperature measuring unit (18) configured to measure a temperature (Tc) of the spindle, wherein the storage unit (36) is designed to store the vibration natural frequency (Fe) associated with the temperature (Tc) of the spindle, and wherein the determination unit (40) is designed to determine whether the absolute value (|Ft - Fe |) of the difference between the vibration natural frequency (Fe) corresponding to the temperature (Tc) of the spindle and the tool vibration frequency (Ft) is equal to or less than the threshold value (TH). [6] The diagnostic device (10) according to any one of claims 1 to 5, wherein the distance detection unit (28) is configured to determine the distance (D) of the strips from the surface roughness of the surface of the workpiece, which is measured by a surface roughness measuring unit (20). [7] The diagnostic device (10) according to claim 6, wherein the distance detection unit (28) is configured to calculate the distance between the strips based on a surface roughness parameter as a measurement result of the surface roughness measuring unit (20). [8] A method for diagnosing the cause of streaks produced on the surface of a workpiece on which mirror surface machining was carried out by a machine tool (12) by moving a tool attached to a spindle relative to the workpiece, the method comprising: a first step in which a spindle rotation frequency (Fm) of the spindle is determined by a spindle rotation frequency detection unit (26), a second step in which a distance (D) of the stripes produced on the surface of the workpiece is determined by a distance detection unit (28), a third step in which a feed rate detection unit (30) determines a feed rate (V) of the tool when the mirror surface machining is performed on the surface of the workpiece, a fourth step in which a stripe frequency (Fp), which is one cause of the stripes, is calculated by a stripe frequency calculator (32) based on the distance (D) of the stripes and the feed rate (V) of the tool, a fifth step in which a trigger frequency calculator (34) is used to calculate a trigger frequency (Fc) that causes vibrations with the strip frequency (Fp) based on the spindle rotation frequency (Fm) and the strip frequency (Fp), and a sixth step in which a notification unit (24) indicates whether or not there is a peripheral device in the vicinity of the machine tool (12) that generates vibrations with the trigger frequency (Fc). [9] The diagnostic method according to claim 8, wherein the trigger frequency calculator (34) calculates the trigger frequencies (Fc) by adding the strip frequency (Fp) to the spindle rotation frequency (Fm) and by subtracting the strip frequency (Fp) from the spindle rotation frequency (Fm). [10] The diagnostic method according to claim 9, wherein the trigger frequency calculator (34) calculates the trigger frequencies (Fc) by adding the strip frequency (Fp) to the spindle rotation frequency (Fm) N times or 1 / N times and by subtracting the strip frequency (Fp) from the spindle rotation frequency (Fm) N times or 1 / N times, where N is an integer greater than or equal to 2. [11] The diagnostic method according to any one of claims 8 to 10, further comprising the following steps: Storing a vibration natural frequency (Fe) of the spindle in a storage unit (36), Calculating a tool vibration frequency (Ft) associated with the spindle rotation, based on the spindle rotation frequency (Fm) and a number of cutting teeth (Cn) of the tool, using a tool vibration frequency calculator (38), and Determine whether an absolute value (|Ft - Fe |) of the difference between the vibration natural frequency (Fe) and the tool vibration frequency (Ft) is equal to or less than a threshold value (TH), or not by a unit of determination (40), wherein the notification unit (24) indicates that the stripes are caused by vibrations at the tool vibration frequency (Ft) when the determination unit (40) determines that the absolute value (|Ft - Fe |) is equal to or less than the threshold value (TH). [12] The diagnostic method according to claim 11, wherein the storage unit (36) stores the vibration natural frequency (Fe) corresponding to a temperature (Tc) of the spindle measured by a spindle temperature measuring unit (18), and wherein the determination unit (40) determines whether the absolute value (|Ft - Fe |) of the difference between the vibration natural frequency (Fe) corresponding to the temperature (Tc) of the spindle and the tool vibration frequency (Ft) is equal to or less than the threshold value (TH). [13] The diagnostic method according to any one of claims 8 to 12, wherein the distance detection unit (28) determines the distance (D) of the strips from the surface roughness of the surface of the workpiece, which was measured by a surface roughness measuring unit (20). [14] The diagnostic method according to claim 13, wherein the distance detection unit (28) calculates the distance (D) of the strips on the basis of a surface roughness parameter as a measurement result of the surface roughness measuring unit (20).

Images