Processing device, evaluation device and evaluation method

Abstract

To provide processing equipment which sets proper working conditions and which can set the working conditions capable of establishing compatibility between a working speed of a workpiece and working quality, an evaluation device, and an evaluation method.SOLUTION: Processing equipment includes a display part that evaluably displays a working quality state within a chart by graphically showing a relationship between the working quality state and working conditions based on a working speed Vc evaluated from the rotating speed and blade diameter of a rotary tool and a working efficiency Q indicating a removal amount removed from the workpiece when the rotary tool is moved in a working direction at the travel speed Vf.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a processing device, an evaluation device, and an evaluation method. [Background technology]

[0002] Generally, when processing a workpiece, particularly when cutting, variations in processing quality may occur depending on the processor (operator). Conventionally, a technique has been proposed in which a relationship diagram between the rotation axis of a tool and the cutting depth is created to find appropriate machining conditions (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-008364 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if appropriate machining conditions are found, variations in the quality of the machined parts may occur due to differences in the equipment, machining conditions, characteristics of the non-cutting material, etc. There is also a demand to maintain machining quality while increasing the machining speed. The present invention has been made in view of the above background, and aims to provide a processing device, an evaluation device, and an evaluation method that can set appropriate processing conditions and can set processing conditions that can achieve both the processing speed and processing quality of the workpiece. [Means for solving the problem]

[0005] In this aspect, a processing device equipped with a rotary tool for processing a workpiece is provided with a display unit that graphs the relationship between processing conditions based on a processing speed Vc calculated from the rotation speed and cutting diameter of the rotary tool and a processing efficiency Q indicating the amount of removal from the workpiece when the rotary tool is moved in the processing direction at a moving speed Vf, and a state of processing quality, and displays the state of processing quality in the graph so that it can be evaluated. The processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band to obtain an average value from the total value of all frequency bands. The processing device is characterized by the above.

[0006] In this aspect, an evaluation device for evaluating the state of machining quality for machining conditions of a workpiece includes a display unit that graphs the relationship between the machining conditions and the state of machining quality, based on the machining speed Vc calculated from the rotation speed and cutting diameter of a rotary tool and the machining efficiency Q indicating the amount of removal from the workpiece when the rotary tool is moved in the machining direction at a moving speed Vf, and displays the state of machining quality in the graph so that it can be evaluated. The processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band to obtain an average value from the total value of all frequency bands. The evaluation device is characterized by the above.

[0007] In this aspect, in an evaluation method for evaluating the state of machining quality for the machining conditions of a workpiece, a graph is created showing the relationship between the machining conditions and the state of machining quality, based on the machining speed Vc calculated from the rotation speed and cutting diameter of a rotary tool and the machining efficiency Q indicating the amount of removal removed from the workpiece by moving the rotary tool in the machining direction at a moving speed Vf, and the graph displays the state of machining quality in an evaluable manner. In the evaluation method, the processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band to obtain an average value from the total value of all frequency bands. The evaluation method is characterized by the above. [Effects of the Invention]

[0008] According to this embodiment, a display unit is provided that graphs the relationship between the processing conditions, which are the processing speed Vc and the processing efficiency Q, and the processing quality, and displays the state of the processing quality within the graph in an evaluable manner.Therefore, by visually checking the display unit, the processor can set appropriate processing conditions during work, and can set processing conditions that can achieve both the processing speed Vc and the processing quality of the workpiece. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 illustrates a first embodiment. [Figure 2] FIG. 10 is a diagram showing the relationship between the processing conditions and the state of processing quality for a first workpiece. [Figure 3] FIG. 1A is a cross-sectional view of a rotary tool, FIG. 1B is an explanatory diagram of the rotary tool being moved to machine a workpiece, and FIG. 1C is a diagram schematically showing the amount of material (chips) removed from the workpiece. [Figure 4] FIG. 10 illustrates a second embodiment. [Figure 5] 1A shows vibration waves of cutting noise, and FIG. 1B shows actual vibration waves of sound pressure levels of cutting noise obtained by FFT analysis. [Figure 6] FIG. 10 is a diagram showing the relationship between the processing conditions and the processing quality state for a second workpiece. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] Referring to FIG. 1, an embodiment of a processing device 1 according to the present embodiment will be described. The processing device 1 includes a processing unit 2 that processes a workpiece W. The processing unit 2 is configured by attaching an end mill (rotary tool) 5 to a gripping unit 4 of a processing machine body 3. A workpiece W is supported and fixed by a holding unit 6. The processing device 1 is configured to include a microphone (measuring unit) 7 that measures the sound pressure of the processing sound (cutting sound) of the workpiece W. The microphone 7 measures with high precision the sound pressure of the cutting sound generated when the processing unit 2 cuts the workpiece W, over a range of frequencies from low to high.

[0011] The processing device 1 includes an evaluation device 8. The evaluation device 8 is a computer that includes a processor, a memory device, a storage device, and an interface circuit. The processor executes a control program stored in the memory device or the storage device to realize various functions of the evaluation device 8. The processor is, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The memory device is, for example, a read-only memory (ROM) or a random access memory (RAM). The storage device is, for example, a hard disk drive (HDD) or a solid state drive (SSD).

[0012] The evaluation device 8 includes a display unit 9 as hardware. The display unit 9 is, for example, a liquid crystal display. The display unit 9 according to this embodiment displays a graph showing the correlation between the machining conditions and the state of machining quality, so that the operator (worker) can easily visually find the appropriate machining conditions. The display unit 9 displays the state of machining quality in an evaluable manner within the graph. In this embodiment, as shown in FIG. 2, the display unit 9 takes the machining speed Vc, which is a first machining condition, on the horizontal axis and the machining efficiency Q, which is a second machining condition, on the vertical axis, and displays the state of machining quality (surface roughness of the machined surface) within a coordinate plane in an evaluable manner. In other words, for the machining efficiency Q and the machining speed Vc, which are machining conditions, the display unit 9 displays a map, as an example of a graph, showing the correlation between a plurality of combinations of the machining efficiency Q and the machining speed Vc and the state of the machining quality of the workpiece W when cutting is performed using each combination.

[0013] The machining speed Vc [m / min] on the horizontal axis is calculated from the rotation speed of the end mill 5 and the cutting diameter D shown in FIG. 3A, and is calculated by equation (1) when the cutting diameter D [mm] of the rotary tool and the rotation speed n [rpm] of the end mill 5. Vc=(π×D×n) / 1000 …(1)

[0014] Vertical axis machining efficiency Q [mm 3 / min] corresponds to the amount of removal (chips) removed from the workpiece W when the end mill 5 is moved in the machining direction at a moving speed Vf [mm / min] as shown in FIG. 3B. The moving speed Vf is calculated by the formula (2) when the number of teeth of the end mill 5 is Z (in Figure 3A, Z = 2), the rotation speed of the end mill 5 is n, and the feed amount per cutting tooth is Fz (mm) (see Figure 3A). Vf=n×Fz×Z …(2) The machining efficiency Q corresponds to the volume shown in FIG. 3C, and is calculated by equation (3) when the moving speed is Vf, the machining depth is Ap [mm], and the machining width is Ae [mm]. Q = Vf × Ap × Ae … (3)

[0015] The map displayed by the display unit 9 is created, for example, by setting the machining speed Vc and machining efficiency Q in advance in the actual machine and checking whether the machining quality of the workpiece W obtained by actually machining is good or bad.

[0016] The evaluation device 8 of this embodiment includes an acquisition unit 10, a creation unit 11, and an output unit 12 as functional units of the evaluation device 8. The acquiring unit 10 acquires machining performance data for the machining efficiency Q and the machining speed Vc. The machining performance data is data that associates a plurality of combinations of the machining efficiency Q and the machining speed Vc with the state of the machining quality of the workpiece W when cutting is performed using each combination.

[0017] The machining performance data is created as follows. That is, the machining speed Vc and machining efficiency Q are set in advance in the actual machine, and a workpiece W made of a predetermined material is actually machined at these machining speed Vc and machining efficiency Q. Then, an evaluation value is assigned to the state of the machining quality of the workpiece W actually obtained at the machining speed Vc and machining efficiency Q. The evaluation value may be, for example, a specific measured value or a numerical value assigned by a machine operator through visual evaluation or the like. The machining performance data is created by associating the machining speed Vc, machining efficiency Q, and evaluation value. The acquisition unit 10 acquires the machining performance data by inputting the machining performance data into the evaluation device 8.

[0018] The creation unit 11 assigns the machining efficiency Q and the machining speed Vc to each axis of a two-axis coordinate system based on the machining performance data, and creates an evaluation map (see FIG. 2) by assigning a shade of the same color corresponding to the evaluation value of each combination at the coordinate position of each combination. Specifically, the creation unit 11 takes the machining speed Vc as the horizontal axis and the machining efficiency Q as the vertical axis. The creation unit 11 then assigns a shade of the same color corresponding to the evaluation value corresponding to the machining speed Vc and the machining efficiency Q to the coordinate positions corresponding to the machining speed Vc and the machining efficiency Q. In this embodiment, the creation unit 11 assigns shades so that the evaluation value increases (the machining quality deteriorates) from a dark state L to a light state H. The creation unit 11 may be configured to assign colors to the coordinate positions of each combination instead of assigning shades. In this case, for example, a dark blue or blue may be assigned to a state of good machining quality, and red or yellow may be assigned to a state of poor machining quality. The output unit 12 outputs the created evaluation map to the display unit 9.

[0019] FIG. 2 shows an evaluation map of a workpiece W made of a predetermined aluminum alloy as a first workpiece. In FIG. 2, the state of the surface roughness of the machined surface as a processing quality is displayed using different shades of black (same color). In FIG. 2, solid contour lines are used to indicate areas with different processing quality states. As a result, in the graph of FIG. 2, the rough contour line portion MK1 has good surface roughness, while the dense solid line portions MK2 and MK3 have poor surface roughness.

[0020] The inventors have confirmed that by displaying the state of the surface roughness of the machined surface in a map showing the machining speed Vc and machining efficiency Q as machining conditions, as shown in FIG. 2, a state of good machining quality (rough part MK1) can be displayed across almost the entire area of ​​the graph, regardless of whether the machining speed Vc is slow or fast. Generally, it is predicted that a high machining speed Vc will result in poor machining quality, but it has been found that even if the machining speed Vc is high, good machining quality can be achieved depending on the setting of the machining efficiency Q. Specifically, in the map of Figure 2, in the region where the machining speed Vc is high, it can be seen that the portion MK1 with good machining quality extends between the portions MK2 and MK3 with poor machining quality.

[0021] According to this embodiment, the processor can evaluate in advance the machining state when machining is actually performed by looking at the display unit 9 of the evaluation device 8. That is, the processor visually checks the display unit 9 and sets the machining conditions when machining is actually performed by the machining device 1 so that, for example, the machining speed Vc and machining efficiency Q correspond to the position on the map of the rough portion MK1. When setting the machining conditions, it is sufficient to change one or more elements such as the machining speed Vc (rotary tool rotation speed n), movement speed Vf, machining depth Ap, machining width Ae, and feed rate Fz per machining blade.

[0022] According to this embodiment, the processor can set appropriate processing conditions during work, and can set processing conditions that can achieve both the processing speed Vc of the workpiece W and the processing quality (surface roughness of the processed surface).

[0023] In FIG. 2, the machining quality is displayed as surface roughness. However, according to a demonstration test by the present inventors, it was found that the same evaluation results as when the machining quality is displayed as surface roughness can be obtained even if the machining quality is displayed as the amount of machining error, machining resistance, acceleration of the end mill 5 due to vibration, etc.

[0024] [Second embodiment] Fig. 4 is a configuration diagram of the second embodiment. Note that the same parts as in Fig. 1 are given the same reference numerals and their explanation will be omitted. In the second embodiment, the machining quality is represented by a machining quality parameter Fs. The evaluation device 8 includes a generating unit 20 that generates the machining quality parameter Fs. The generating unit 20 generates the machining quality parameter Fs based on vibration waves during machining obtained from the sound pressure (sound pressure level) of machining sounds (cutting sounds) measured by the microphone 7.

[0025] Specifically, the generation unit 20 acquires the vibration wave of the cutting sound measured by the microphone 7 as shown in FIG. 5A, and uses FFT (Fast Fourier Transformation) analysis to obtain the relationship between frequency and sound pressure as shown in FIG. 5B, and generates a processing quality parameter Fs (Formulated Sound) index expressed by the following equation (4).

number

[0026]

number

[0027] The processing quality parameter Fs is calculated by measuring the sound pressure Pa in the frequency band from the low frequency region to the high frequency region, calculating the average sound pressure Pi for each frequency band, and averaging the total value of all frequency bands obtained by multiplying the average sound pressure Pi by the frequency for each frequency band, and then calculating the average value using the above formula (4). It was found that the machining quality parameter Fs is a combination of the low frequency band of the fundamental wave and the high frequency band sound pressure component, so it has a high correlation with the state of machining quality (for example, the surface roughness of the machined surface, the amount of error on the machined surface, etc.). The correlation coefficient in these cases was about R = 0.86.

[0028] Fig. 6 shows an evaluation map of a workpiece W made of a predetermined titanium alloy as a second workpiece. As shown in Fig. 6, the inventors have created a map with machining speed Vc on the horizontal axis and machining efficiency Q on the vertical axis as machining conditions, and have displayed a machining quality parameter Fs obtained from the machining sound (cutting sound) of the workpiece W as an index showing the state of machining quality. That is, in the second embodiment, the value of the machining quality parameter Fs is used as the evaluation value of the machining performance data. In FIG. 6, the dark portion MK4 is an area with good processing quality, and the light portion MK5 above the dark portion MK4 in the figure is an area with poor processing quality.

[0029] In the second embodiment, the operator visually checks the display unit 9 and sets the processing conditions so that the processing conditions fall within the area displayed by the dark portion MK4, for example. In setting the machining conditions, as in the first embodiment, it is sufficient to change and set one or more elements such as the machining speed Vc (rotation speed n of the rotary tool), the moving speed Vf, the machining depth Ap, the machining width Ae, and the feed amount Fz per machining blade.

[0030] In the second embodiment, the processor can set appropriate processing conditions during work, and can set processing conditions that can achieve both the processing speed Vc of the workpiece W and the processing quality (surface roughness of the processed surface).

[0031] In the second embodiment, the machining quality parameter Fs index is expressed by equation (4), which incorporates high-frequency sensitivity to cutting noise during cutting, which has a strong correlation with quality. Therefore, by using the Fs index, the state of machining quality can be displayed with higher accuracy.

[0032] [Other embodiments] The present invention is not limited to the above-described embodiment. The above-described embodiment is directed to the machining quality when machining with an end mill 5, but may also be directed to machining with any rotary tool, such as a drilling tool.

[0033] In the first and second embodiments, the processing conditions and the processing quality status are displayed as a map. However, the present invention is not limited to this. For example, instead of using colors or densities, numbers or letters indicating the evaluation may be displayed in the graph.

[0034] In the above first and second embodiments, the processor visually checks the display unit 9 and sets the actual machining conditions so that the machining speed Vc and machining efficiency Q correspond to the position selected by the processor. However, this is not limiting. For example, the evaluation device 8 may set the actual machining conditions so that the machining speed Vc and machining efficiency Q correspond to the position selected by the processor. That is, the evaluation device 8 may include a receiving unit that receives input of position coordinates on a map (graph), identify the machining speed Vc and machining efficiency Q corresponding to the received position coordinates, and set the identified machining speed Vc and machining efficiency Q in the machining device 1 to operate the machining device 1.

[0035] Specifically, for example, the evaluation device 8 is provided with a touch panel that serves as the display unit 9 and has an input function. The evaluation device 8 is configured such that when the output unit 12 outputs the evaluation map to the display unit 9, the reception unit receives touch input from the display unit 9. The evaluation device 8 then waits to see if the state of machining quality on the map is touched, and if so, identifies the machining speed Vc and machining efficiency Q corresponding to the touched position coordinates on the map. The evaluation device 8 may then set the identified machining speed Vc and machining efficiency Q in the machining device 1 and operate the machining device 1. Note that at this time, the evaluation device 8 may be configured to calculate the moving speed Vf so that the machining efficiency Q is achieved by previously setting the machining depth Ap, machining width Ae, etc. in the evaluation device 8.

[0036] [Configuration supported by the above embodiment] The above embodiment is a specific example of the following configuration.

[0037] (Configuration 1) A processing device equipped with a rotary tool for processing a workpiece, characterized in that the processing device is equipped with a display unit that graphs the relationship between processing conditions based on a processing speed Vc calculated from the rotation speed and blade diameter of the rotary tool and a processing efficiency Q indicating the amount of material removed from the workpiece when the rotary tool is moved in the processing direction at a moving speed Vf, and the state of processing quality, and displays the state of processing quality in the graph in an evaluable manner. According to the processing device of configuration 1, a display unit is provided that displays the state of processing quality in an evaluable manner, so that the processor can visually confirm appropriate processing conditions and set processing conditions that can achieve both processing speed and processing quality for the workpiece.

[0038] (Configuration 2) The processing device according to Configuration 1, characterized in that good and bad states of the processing quality are displayed in different colors or shades. According to the processing device of configuration 2, good and bad conditions are displayed in different colors or shades, making it easy to check.

[0039] (Configuration 3) The machining speed Vc is calculated by the formula (1) where D is the cutting diameter of the tool and n is the rotation speed of the tool. Vc=(π×D×n) / 1000 …(1) 3. The processing device according to configuration 1 or 2. According to the processing device of configuration 3, the processing speed Vc can be easily determined.

[0040] (Configuration 4) The machining efficiency Q is calculated by the formula (2) when the moving speed Vf, machining depth Ap, and machining width Ae are used, and the moving speed Vf is calculated by the formula (3) when the number of blades of the tool Z, the number of rotations of the tool n, and the feed amount per machining blade Fz are used. Q = Vf × Ap × Ae … (2) Vf=n×Fz×Z …(3) 4. The processing device according to any one of configurations 1 to 3, According to the processing device of configuration 4, the processing efficiency Q can be easily determined.

[0041] (Configuration 5) A processing device described in any one of configurations 1 to 4, characterized in that good and bad states of the processing quality are displayed over almost the entire range of the graph, regardless of whether the processing speed Vc is fast or slow. According to the processing device of configuration 5, it is possible to confirm appropriate processing conditions in the region where the processing speed Vc is fast, and to set processing conditions that can achieve both processing speed and processing quality.

[0042] (Configuration 6) The processing device according to any one of Configurations 1 to 5, wherein the processing quality corresponds to at least one of surface roughness, error amount, processing resistance, and acceleration. According to the processing device of configuration 6, when the processing quality is displayed in the graph, whether it is surface roughness, error amount, processing resistance, or acceleration, appropriate processing conditions can be set.

[0043] (Configuration 7) The processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band, and obtaining an average value from the total value of all frequency bands. According to the processing device of configuration 7, the state of processing quality can be displayed with higher accuracy by using the processing quality parameter Fs index, which incorporates high frequency sensitivity to processing sound that has a strong correlation with quality. Therefore, appropriate processing conditions can be visually confirmed, and processing conditions that can achieve both processing speed and processing quality can be set.

[0044] (Configuration 8) An evaluation device for evaluating the state of machining quality for the machining conditions of a workpiece, characterized by comprising a display unit that graphs the relationship between the machining conditions and the state of machining quality, based on the machining speed Vc calculated from the rotation speed and cutting diameter of a rotary tool and the machining efficiency Q indicating the amount of removal from the workpiece by moving the rotary tool in the machining direction at a moving speed Vf, and displays the state of machining quality in the graph so that it can be evaluated. According to the evaluation device of configuration 8, since it is equipped with a display unit that displays the state of the processing quality in an evaluable manner, the processor can visually confirm appropriate processing conditions and set processing conditions that can achieve both the processing speed and processing quality of the workpiece.

[0045] (Configuration 9) An evaluation method for evaluating the state of machining quality for the machining conditions of a workpiece, characterized in that the relationship between the machining conditions and the state of machining quality is graphed based on the machining speed Vc calculated from the rotation speed and cutting diameter of a rotary tool and the machining efficiency Q indicating the amount of material removed from the workpiece by moving the rotary tool in the machining direction at a moving speed Vf, and the graph is displayed so that the state of machining quality can be evaluated. According to the evaluation method of configuration 9, it is possible to visually check and set processing conditions that can achieve both the processing speed and processing quality of the workpiece. [Explanation of symbols]

[0046] 1 Processing equipment 2 Processing section 3 Processing machine body 5 End mill (rotary tool) 7 Microphone (measurement unit) 8 Evaluation equipment 9 Display section 10 Generation part Ae processing width Ap machining depth D Tool cutting diameter Fz Feed rate per cutting edge n Tool rotation speed Q Machining efficiency Vc machining speed Vf movement speed W Workpiece Z Number of tool teeth

Claims

1. In a processing device equipped with a rotary tool for processing a workpiece, a display unit that graphs the relationship between machining conditions based on a machining speed Vc calculated from the rotation speed and cutting diameter of the rotary tool and a machining efficiency Q indicating the amount of removal from the workpiece when the rotary tool is moved in the machining direction at a moving speed Vf, and a state of machining quality, and displays the state of machining quality in the graph so that it can be evaluated; The processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band to obtain an average value from the total value of all frequency bands.

2. 2. The processing device according to claim 1, wherein the good and bad states of the processing quality are displayed in different colors or shades.

3. The machining speed Vc can be calculated by the formula (1) where D is the cutting diameter of the tool and n is the rotation speed of the tool. Vc=(π×D×n) / 1000…(1) 3. The processing device according to claim 1 or 2.

4. The machining efficiency Q is calculated by the formula (2) when the moving speed Vf, the machining depth Ap, and the machining width Ae are used, and the moving speed Vf is calculated by the formula (3) when the number of blades of the tool Z, the number of rotations of the tool n, and the feed amount per machining blade Fz are used. Q=Vf×Ap×Ae…(2) Vf=n×Fz×Z…(3) 4. The processing device according to claim 1, wherein the processing device is a processing device for processing a workpiece.

5. 5. The processing device according to claim 1, wherein good and bad states of the processing quality are displayed over almost the entire range of the graph, regardless of whether the processing speed Vc is high or low.

6. An evaluation device for evaluating a state of processing quality for processing conditions of a workpiece, a display unit that graphs the relationship between machining conditions based on a machining speed Vc determined from the rotation speed and cutting diameter of a rotary tool and a machining efficiency Q that indicates the amount of removal from the workpiece when the rotary tool is moved in the machining direction at a moving speed Vf, and the state of machining quality, and displays the state of machining quality in the graph so that it can be evaluated; The processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band to obtain an average value from the total value of all frequency bands.

7. 1. An evaluation method for evaluating the state of processing quality of a workpiece with respect to processing conditions, comprising: An evaluation method for graphing the relationship between machining conditions based on a machining speed Vc determined from the rotation speed and cutting diameter of a rotary tool and a machining efficiency Q indicating the amount of removal removed from the workpiece when the rotary tool is moved in the machining direction at a moving speed Vf, and a state of machining quality, and displaying the state of machining quality in an evaluable manner within the graph, comprising: The processing quality corresponds to a processing quality parameter Fs obtained from the processing sound of the workpiece, and the processing quality parameter Fs is obtained by measuring the magnitude of sound pressure Pa in a frequency band from a low frequency region to a high frequency region, calculating an average sound pressure Pi for each frequency band, and multiplying the average sound pressure Pi by the frequency for each frequency band to obtain an average value from the total value of all frequency bands.

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