JP7797243B2 - Processing device, evaluation device and evaluation method - Google Patents

Description

The present invention relates to a processing device, an evaluation device, and an evaluation method.

Generally, when processing a workpiece, particularly when cutting the workpiece, 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).

JP 2018-008364 A

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.

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 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 so that it can be evaluated , wherein the processing quality corresponds to a processing quality parameter Fs calculated from processing sound of the workpiece, and the processing quality parameter Fs is calculated 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 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.

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, 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 the state of machining quality, and displays the state of machining quality in the graph so that it can be evaluated , and the machining quality corresponds to a machining quality parameter Fs calculated from the machining sound of the workpiece, and the machining quality parameter Fs is calculated 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 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 .

In this aspect, an evaluation method for evaluating the state of machining quality for the machining conditions of a workpiece includes graphing the relationship between the machining conditions, which are determined by the machining speed Vc calculated from the rotation speed and cutting diameter of a rotary tool, and the machining efficiency Q, which indicates the amount of removal removed 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 displaying the state of machining quality in an evaluable manner on the graph, wherein the machining quality corresponds to a machining quality parameter Fs calculated from the machining sound of the workpiece, and the machining quality parameter Fs is calculated 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 calculating the average sound pressure Pi by the frequency for each frequency band, and averaging the total value of all frequency bands .

According to this aspect, a display unit is provided that graphs the relationship between the machining conditions (machining speed Vc and machining efficiency Q) and the machining quality, and displays the state of the machining quality within the graph in an evaluable manner. This allows the worker to visually check the display unit and set appropriate machining conditions during work, enabling them to set machining conditions that achieve both the machining speed Vc and the machining quality of the workpiece.

FIG. 1 illustrates a first embodiment. FIG. 10 is a diagram showing the relationship between the processing conditions and the state of processing quality for a first workpiece. 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 removal (chips) from the workpiece. FIG. 10 illustrates a second embodiment. 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. FIG. 10 is a diagram showing the relationship between the processing conditions and the processing quality state for a second workpiece.

[First embodiment]
Referring to FIG. 1, an embodiment of a processing device 1 according to the present invention 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 processing sounds (cutting sounds) of the workpiece W. The microphone 7 measures with high precision the sound pressure of cutting sounds generated when the processing unit 2 cuts the workpiece W, over a range of frequencies from low to high.

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 control programs stored in the memory device or storage device to realize the various functions of the evaluation device 8. The processor is, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The memory device is, for example, a ROM (Read Only Memory) or a RAM (Random Access Memory). The storage device is, for example, a HDD (Hard Disk Drive) or an SSD (Solid State Drive).

The evaluation device 8 includes a display unit 9 as hardware. The display unit 9 is, for example, an LCD display. In this embodiment, the display unit 9 displays a graph showing the correlation between processing conditions and processing quality, allowing the operator (worker) to visually identify appropriate processing conditions. The display unit 9 displays the processing quality in an evaluable manner within the graph. In this embodiment, as shown in FIG. 2, the display unit 9 displays the processing quality (surface roughness of the processed surface) in an evaluable manner within a coordinate plane, with the horizontal axis representing the processing speed Vc, which is the first processing condition, and the vertical axis representing the processing efficiency Q, which is the second processing condition. In other words, the display unit 9 displays a map, as an example of a graph, showing the correlation between multiple combinations of processing efficiency Q and processing speed Vc, which are processing conditions, and the processing quality of the workpiece W when cutting is performed using each combination.

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

The machining efficiency Q [mm ³ /min] on the vertical axis corresponds to the amount of removal (chips) 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 Figure 3B.
The moving speed Vf is calculated by the formula (2) when the number of blades of the end mill 5 is Z (Z=2 in FIG. 3A), the number of rotations of the end mill 5 is n, and the feed amount per cutting blade is Fz (mm) (see FIG. 3A).
Vf=n×Fz×Z…(2)
The machining efficiency Q corresponds to the volume shown in FIG. 3C, and is calculated by the formula (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)

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

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 acquisition unit 10 acquires machining performance data regarding 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.

The machining performance data is created as follows. That is, the actual machine is set in advance to have a machining speed Vc and machining efficiency Q, and a workpiece W made of a specified material is actually machined using these machining speed Vc and machining efficiency Q. An evaluation value is then assigned to the state of the machining quality of the workpiece W actually obtained using 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 the machine operator through visual evaluation, etc. Machining performance data is created by correlating the machining speed Vc, machining efficiency Q, and evaluation value. The acquisition unit 10 acquires the machining performance data when the machining performance data is input into the evaluation device 8.

The creation unit 11 creates an evaluation map (see FIG. 2 ) by assigning 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 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 such that the evaluation value increases (the machining quality deteriorates) from a dark state L to a light state H. The creation unit 11 may 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 good machining quality state, and a red or yellow may be assigned to a bad machining quality state.
The output unit 12 outputs the created evaluation map to the display unit 9 .

Figure 2 shows an evaluation map of a workpiece W made of a specified aluminum alloy as a first workpiece. In Figure 2, the state of the surface roughness of the machined surface, which is a measure of processing quality, is displayed using different shades of black (same color). Figure 2 also shows solid contour lines to indicate areas with different processing quality states. As a result, in the graph of Figure 2, the area MK1 with the rough solid contour lines has good surface roughness, while the areas MK2 and MK3 with the dense solid lines have poor surface roughness.

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 Figure 2, a state of good machining quality (rough part MK1) can be displayed over almost the entire area of the graph, regardless of whether the machining speed Vc is slow or fast.
In general, 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 a portion MK1 with good machining quality is displayed extending between portions MK2 and MK3 with poor machining quality.

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 (rotation speed n of the rotary tool), the movement speed Vf, the machining depth Ap, the machining width Ae, and the feed amount Fz per machining blade.

This embodiment allows the operator to set appropriate machining conditions during work, and also allows the operator to set machining conditions that achieve both the machining speed Vc of the workpiece W and the machining quality (surface roughness of the machined surface).

In Figure 2, the machining quality is displayed as surface roughness, but according to demonstration tests conducted by the inventors, it was found that the same evaluation results could be obtained when the machining quality was displayed as surface roughness, even if it was displayed as machining error, machining resistance, or acceleration of the end mill 5 due to vibration.

[Second embodiment]
Fig. 4 is a diagram showing the configuration of the second embodiment. Note that the same parts as those 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.

Specifically, as shown in FIG. 5A, the generation unit 20 acquires the vibration wave of the cutting sound measured by the microphone 7, 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).
In formula (4), Fs is the processing quality parameter, fi is a predetermined frequency as a representative value in the i-th frequency band, and Pi bar is the average sound pressure in the i-th frequency band. Note that in formulas (4) and (5), Pi bar represents the average sound pressure in the i-th frequency band (i = j, j + 1, ..., k - 1, k), but in formulas other than (4) and (5), the bar is omitted and the average sound pressure in the i-th frequency band is simply represented by Pi.

Here, the average sound pressure Pi in equation (4) is calculated as follows. That is, the measurement time for data such as that shown in FIG. 5A is divided into predetermined periods t. Then, FFT analysis is performed for each jth period tj (j=m, m+1, ..., n-1, n). As a result, a relationship between frequency and sound pressure, as shown in FIG. 5B, is obtained for each predetermined period tj. That is, the relationship between frequency fi and sound pressure Pij is obtained for each predetermined period tj. In other words, FFT analysis is performed in real time during measurement, and the relationship between frequency fi and sound pressure Pij is obtained for each predetermined period tj. Here, considering the change in sound pressure Pij over the predetermined period ti using the i-th frequency fi as a reference, in the i-th frequency band, sound pressure Pij changes as Pim, Pim+1, ..., Pin-1, Pin. Therefore, the average sound pressure Pi of the i-th frequency band is calculated as Pi=(Pim+Pim+1+ . . . +Pin-1+Pin)/(n-m), which is given by equation (5).

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

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 of machining conditions, with the horizontal axis representing machining speed Vc and the vertical axis representing machining efficiency Q, 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 a portion with good processing quality, and the light portion MK5 above the dark portion MK4 in the drawing is displayed as a portion with poor processing quality.

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, any 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 may be changed and set.

In the second embodiment, the operator can set appropriate machining conditions during work, and can set machining conditions that achieve both the machining speed Vc of the workpiece W and machining quality (surface roughness of the machined surface).

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 this Fs index, the state of machining quality can be displayed with greater accuracy.

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 be directed to machining with any rotary tool, such as a drilling tool.

In the first and second embodiments described above, a configuration was described in which the processing conditions and processing quality status were displayed as a map, but this is not limited to this. For example, instead of color or density, numbers or letters indicating the evaluation may be displayed within the graph.

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 be configured to 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 reception 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 processing device 1 to operate the processing device 1.

Specifically, for example, the evaluation device 8 is equipped with a display unit 9 and a touch panel with input functionality. The evaluation device 8 is configured so that when the output unit 12 outputs an 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 machining quality status 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 in this case, the evaluation device 8 may be configured to calculate the movement 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.

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

(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 so that it can be evaluated.
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.

(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.

(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.

(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.

(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.

(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 machining device of configuration 6, when the machining quality is displayed in a graph, whether it is surface roughness, error amount, machining resistance, or acceleration, appropriate machining conditions can be set.

(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 to obtain 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 that 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.

(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 removed 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.

(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.

1 Processing device 2 Processing section 3 Processing machine body 5 End mill (rotary tool)
7. Microphone (measuring unit)
8 Evaluation device 9 Display unit 10 Generation unit Ae Machining width Ap Machining depth D Tool blade diameter Fz Feed rate per machining blade n Tool rotation speed Q Machining efficiency Vc Machining speed Vf Moving speed W Workpiece Z Number of tool blades

Claims (7)

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 . The processing device of claim 1, characterized in that good and bad processing quality states are displayed differently using different colors or shades. 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. 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. A processing device as described in any one of claims 1 to 4, characterized in that good and bad processing quality states are displayed across almost the entire range of the graph, regardless of whether the processing speed Vc is high or low. 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 . 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 .