JP2020069639A - Grinding surface state evaluation apparatus and grinding device - Google Patents

Abstract

To provide a grinding surface state evaluation apparatus and a grinding device that can quantitatively evaluate the grinding surface state of a grinding wheel.SOLUTION: An evaluation value representing a grinding surface state calculated based on a first signal intensity SP1 of a first wavelength band B1 associated with the crushing of abrasive grains of a grinding wheel 14 is a value indicating whether crushed grains are many or few, and the smaller the value, the more the progress of loading or glazing of the grinding wheel 14 is reflected. An evaluation value representing a grinding surface state calculated based on a second signal intensity SP2 of a second wavelength band B2 associated with frictional vibration or elastic vibration caused by contact between abrasive grains of the grinding wheel 14 and a ground material is a value indicating whether crushed grains are many or few, and the smaller the value, the more the progress of shedding of the grinding wheel 14 is reflected. This enables that the progress of the shedding of the grinding wheel 14 or the progress of the glazing of the grinding wheel 14 can be quantitatively evaluated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a grinding surface condition monitoring device for evaluating a condition in which a work material is ground by a grinding tool, and a grinding processing device using the grinding surface condition evaluating device, and particularly to accurately evaluate a grinding surface condition. It is about technology.

  An AE signal (acoustic emission signal: a vibration wave whose frequency is an ultrasonic region of 100 kHz or more, for example) that represents a crushing sound generated in association with crushing of abrasive grains included in a grinding tool is detected, and based on the AE signal There has been proposed a device for determining or monitoring a grinding surface condition or a dressing condition of a grinding tool such as grinding burn, clogging, grindstone sharpness, and grindstone peripheral condition.

  For example, in Patent Document 1, a grinding wheel side AE sensor for detecting a grinding wheel side AE signal generated in a vitrified grinding wheel and a work piece for detecting a work material side AE signal generated in a work material. A material side AE sensor, a frequency analysis means for performing frequency analysis on the grinding wheel side AE signal and a work material side AE signal, and a grinding wheel side AE signal and a work material side AE signal subjected to frequency analysis by the frequency analysis means, respectively. Based on the above, there has been proposed a grinding surface state evaluation device capable of sufficiently obtaining the accuracy of the judgment or evaluation of the grinding surface state of the grinding wheel by determining the grinding surface state of the vitrified grinding wheel.

  In the above-mentioned conventional grinding surface state evaluation device, regarding the vitrified grinding wheel, the grinding wheel side AE signal output from the grinding wheel side AE sensor is the interface separation (100 kHz to 2 MHz) between the abrasive grain and the inorganic binder, the abrasive grain itself. The cracks (100 kHz to 2 MHz), the cracks (100 kHz to 2 MHz) of the inorganic binder itself, and the work material side AE signal output from the work material side AE sensor are plastic deformation (100 kHz to 800 kHz) of the work material. ), A brittle fracture (200 kHz to 700 kHz) of the work material is represented, and the original AE signal obtained by frequency analysis from the grinding wheel side AE signal and the work material side AE signal is input to the neural network. By doing so, it is said that, for example, the grinding burn and the surface condition of the grinding wheel are judged.

JP, 2000-233369, A

  However, in the conventional grinding surface state evaluation device, since the grinding tool side AE signal is detected in a wide frequency band, for example, a frequency band of 100 kHz to 2 MHz, a plurality of types of information included in the grinding tool side AE signal is detected. For example, it is not possible to independently detect the crushing sound of the abrasive grains themselves and the frictional signal or elastic vibration due to the contact between the abrasive grains and the work material. The spill could not be evaluated quantitatively.

  When it becomes possible to quantitatively evaluate the crushed state of grindstones such as vitrified grindstones, crushing and spillage, by feeding back to the grinding machine, processing efficiency, wheel peripheral speed, work peripheral speed By controlling the work feed rate and the like, it is possible to maintain appropriate grinding conditions and perform efficient grinding while maintaining the grinding quality.

  The present invention has been made in the background of the above circumstances, the purpose is to crush the state of the abrasive grains, a grinding surface state evaluation device and grinding that can quantitatively evaluate the crush and spillage of the grinding wheel To provide a processing device.

  The present inventor has conducted various studies in the background of the above circumstances, and as a result, after digitizing an AE signal output from an AE sensor mounted on a grinding wheel by using an AD converter of relatively high speed and high resolution, When frequency analysis (FFT) is performed, in the frequency band lower than 100 kHz in the power spectrum, the peak signal group of the first wavelength band of a relatively low frequency and the second wavelength band of a frequency relatively higher than the first wavelength band. We found the fact that the peak signal groups of and appear clearly on the frequency axis. The peak signal group in the first wavelength band is derived from the crushing of the abrasive grains of the grinding wheel, and the peak signal group in the second wavelength band is generated by the contact (rubbing) between the abrasive grains and the work material. We found the fact that it is derived from frictional vibration and elastic vibration. The present invention has been made based on such knowledge.

  That is, the gist of the first invention is (a) a grinding surface condition evaluation device for evaluating a grinding surface condition of a grinding wheel containing abrasive grains for grinding a work material, and (b) the grinding An AE sensor that detects vibration generated at the grinding portion of the grindstone and outputs an AE signal; (c) an A / D converter that converts the AE signal output from the AE sensor into a digital signal; A frequency analysis unit for frequency-analyzing an AE signal converted into a digital signal by an A / D converter to obtain a power spectrum; and (e) a power spectrum obtained by the frequency analysis unit, which is included in the grinding tool. The first signal intensity in the first wavelength band related to the crushing of the abrasive grains and the second signal band in the second wavelength band related to the frictional vibration and the elastic vibration caused by the contact (rubbing) between the abrasive grains of the grinding wheel and the work material. Signal strength A grinding surface that calculates at least one and outputs an evaluation value related to the grinding surface state of the grinding wheel based on at least one of the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band. And a state output section.

  According to the grinding surface state evaluation device of the first aspect of the invention, the evaluation value representing the grinding surface state calculated based on the first signal intensity in the first wavelength band related to the crushing of the abrasive grains of the grinding wheel is the abrasive grains. Is a value that indicates a state in which there is much crushing, and a smaller value reflects the progress of the crushed state of the grinding wheel. An evaluation value representing the grinding surface state calculated based on the second signal intensity in the second wavelength band related to the frictional vibration or the elastic vibration generated by the contact between the abrasive grains of the grinding wheel such as the vitrified grinding wheel and the work material. The smaller the value, the smaller the number of abrasive grains acting, and the progress of the spilled state of the grinding wheel. Thereby, based on the evaluation value calculated by the grinding surface state output unit, the progress of the crushed state of the grinding wheel such as the vitrified grindstone, or the progression of the spilled state of the grinding wheel such as the vitrified grindstone, quantitatively, Can be evaluated.

  Here, preferably, in the grinding surface state evaluation device, at least one of the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band is an integral value or a moving average value, The grinding surface state output unit determines the evaluation value related to the grinding surface state of the grinding wheel based on the at least one of the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band. Output. According to this configuration, the above-mentioned state related to the grinding surface state of the grindstone is based on the integral value or the moving average value of at least one of the first signal intensity in the first wavelength band and the second signal intensity in the second wavelength band. Since the evaluation value is output, since the influence of abnormal values is reduced, the progress of the grinding wheel of the grinding wheel, or the progress of the spilled state of the grinding wheel such as the vitrified wheel can be accurately evaluated. it can.

  Further, preferably, in the grinding surface state evaluation device, the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band are integral values or moving average values, and the grinding surface state is The output unit calculates a signal intensity ratio of the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band, and relates to a grinding surface state of the grinding wheel based on the signal intensity ratio. The evaluation value is output. According to this configuration, the smaller the value, the first signal intensity in the first wavelength band that reflects the progress of the crushed state of the grinding wheel, and the smaller the value, the second signal that reflects the progress of the spilled state of the grinding wheel. The progress of the grinding wheel in the crushed state and the spilled state are emphasized by the ratio of the wavelength band to the second signal intensity, so that the progress of the crushed state of the grinding wheel and the eyes of the grinding wheel are enhanced. It is possible to accurately evaluate the progress of the spilled state.

  Further, preferably, the grinding surface condition evaluation device includes a display device for displaying the evaluation value output from the grinding surface condition output unit. By doing so, it is possible to visually visually evaluate the progress of the state of the grindstone in which the grindstone is crushed and / or the progress of the state of the grindstone in which the grindstone is spilled.

  Further, preferably, in the grinding surface state evaluation device, the first wavelength band is a wavelength band including a part of a wavelength band of 25 to 40 kHz (for example, a central wavelength of the first wavelength band), and the second wavelength band. The wavelength band is a wavelength band including a part of the wavelength band of 45 to 65 kHz (for example, the central wavelength of the second wavelength band). With this configuration, the first signal intensity of the first wavelength band corresponding to the progress of the blind state of the grinding wheel and / or the second signal band of the second wavelength band corresponding to the progress of the spilled state of the grinding wheel. The signal strength can be used to quantitatively evaluate the state of the grinding surface of the grinding wheel.

  Further, preferably, in the grinding surface state evaluation device, the first wavelength band is a wavelength band of 25 to 40 kHz, and the second wavelength band is a wavelength band of 45 to 65 kHz. With this configuration, the first signal intensity of the first wavelength band corresponding to the progress of the blind state of the grinding wheel and / or the second signal band of the second wavelength band corresponding to the progress of the spilled state of the grinding wheel. The signal strength can be used to quantitatively evaluate the state of the grinding surface of the grinding wheel such as the vitrified grinding wheel.

  Further, preferably, in the grinding surface state evaluation device, the sampling cycle of the A / D converter is 10 μsec or less. As described above, according to the A / D converter having a high resolution, the first signal intensity in the first wavelength band that reflects the progress of the crushed state of the grinding wheel from the power spectrum obtained by frequency-analyzing the AE signal, and And / or the second signal intensity in the second wavelength band that reflects the progress of the spilled state of the grinding wheel is preferably obtained.

  Further, preferably, a grinding apparatus that grinds the workpiece using the grinding wheel is such that the evaluation value output from the grinding surface state output unit becomes a preset target evaluation value. An automatic grinding that adjusts at least one of a cutting speed of the grinding wheel into the work material, a peripheral speed of the grinding wheel, a peripheral speed of the work material, and a feed speed of the work material. A control unit is provided. By doing so, the grinding conditions are appropriately and automatically controlled, so that variations in the quality of the work material are suppressed. Further, the dressing interval (the dressing cycle) is extended, and as a result, the life of the grindstone is extended.

  Further, preferably, while grinding the work material using the grinding wheel, a grinding apparatus for dressing the grinding wheel using a dresser, the evaluation value output from the grinding surface state output unit When the dressing start condition is set in advance, the dressing controller is provided to stop the grinding of the work material using the grinding wheel and start the dressing of the grinding wheel by the dresser. With this configuration, dressing is automatically started at an appropriate timing when the spilling and the crushing of the grinding wheel reach a predetermined state, so that the variation in the quality of the work material is suppressed.

It is a figure explaining the composition of the grinding processing device provided with the grinding surface state evaluation device of one example of the present invention. It is a figure explaining the generation | occurrence | production mechanism of the AE signal obtained from the vitrified grindstone in the grinding surface state by the grinding device of FIG. It is a figure which shows the power spectrum obtained from the AE signal wave generated when a ceramic plate was ground using a diamond electrodeposition grindstone. It is a figure which shows the power spectrum obtained from the AE signal wave generated when a ceramic plate was ground using a CBN electrodeposition grindstone. It is a figure which shows the power spectrum obtained from the AE signal wave generated when a ceramic plate was ground using a CBN resinoid grindstone. It is a figure which shows the power spectrum obtained from the AE signal wave generated when the CBN resinoid grindstone was dressed by the rotary dresser. FIG. 3 is a diagram showing a power spectrum obtained in a dressing test in which the peripheral speed ratio Vd / Vg is 1.0, which is a downcut, among the three types of dressing tests performed by the present inventor having different peripheral speed ratios. .. FIG. 3 is a diagram showing a power spectrum obtained in a dressing test performed by the present inventor when the peripheral speed ratio Vd / Vg is 0.3 and downcut, out of three types of dressing tests with different peripheral speed ratios. .. It is a figure which shows the power spectrum obtained in the dressing test when peripheral speed ratio Vd / Vg is 1.0 and it is an up cut among three types of dressing tests which the peripheral speed ratio differed which this inventor performed. .. From the three types of power spectra shown in FIGS. 7 to 9, a threshold value set to indicate the presence of a sufficiently large peak waveform is set, and it is determined that one of the peak waveforms exceeding the threshold value is generated. It is a figure which shows the peak waveform generation map shown by the black area. It is a figure which shows the 1st signal SP1, the 2nd signal SP2, and signal intensity ratio SR obtained when dressing a vitrified grindstone using four types of dressing conditions which differ in peripheral speed ratio, respectively. It is a figure which shows the power spectrum obtained from the AE signal wave generated when the steel material was ground using the CBN vitrified grindstone. It is a figure which shows the power spectrum obtained from the AE signal wave generated when grinding a steel material using a CBN electrodeposition grindstone. When performing repeated grinding using a CBN vitrified grindstone, the first signal intensity SP1 (vibration intensity integrated value) obtained from the first wavelength band B1 and the cumulative number of crushed abrasive grains per unit area of the CBN vitrified grindstone (grain 6 is a broken line graph showing a change in / mm ² ). Changes in the second signal intensity SP2 (vibration intensity integrated value) obtained from the second wavelength band B2 and the working area ratio (%) of the abrasive grains of the CBN vitrified grindstone when the grinding is repeatedly performed using the CBN vitrified grindstone. It is a graph which shows. Vibration intensity ratio (SP1) obtained as an average value of 11 to 14 cuts when repeatedly grinding under four types of processing conditions 1 to 4 in which the peripheral speed of the grinding tool, the cutting speed, and the material of the work material are different. 2 is a bar graph showing the size of / SP2) in a comparable manner. It is a 3D map which measured the grinding surface of the CBN vitrified grindstone after processing on condition 1 of FIG. 16 with the laser microscope. It is a 3D map which measured the grinding surface of the CBN vitrified grindstone after processing on condition 2 of FIG. 16 with the laser microscope. It is a 3D map which measured the grinding surface of the CBN vitrified grindstone after processing by the condition 3 of FIG. 16 with the laser microscope. It is a 3D map which measured the grinding surface of the CBN vitrified grindstone after processing by the condition 4 of FIG. 16 with the laser microscope. It is a figure which shows the power spectrum obtained in the grinding test in case the cutting speed is R0.8 (mm / min) among two kinds of grinding tests with different cutting speeds performed by the inventor. It is a figure which shows the power spectrum obtained in the grinding test in case the cutting speed is R2.8 (mm / min) among two kinds of grinding tests with different cutting speeds performed by the inventor. When the cutting speed was R0.8 (mm / min) as the blinding condition and the cutting speed was R2.8 (mm / min) as the spilling condition, it was obtained in the grinding test under each condition. FIG. 5 is a diagram showing the signal intensity ratio SR (= SP1 / SP2) calculated from the power spectrum as the vertical axis and the grinding allowance cross-sectional area (mm ² / mm) per unit circumferential length of the grinding wheel as the horizontal axis. Grinding Daidan area ^(mm 2 / mm) is a diagram showing an enlarged region of 5 from 0 in FIG. 23. It is a figure which shows the example of a display of the grinding surface state display device of the grinding surface state evaluation device of FIG. It is a figure which shows the other display example of the grinding surface state display device of the grinding surface state evaluation device of FIG. It is a figure which shows the feedback control which makes the actual signal strength ratio SR follow the target signal strength ratio SRT in the automatic control by the grinding automatic control part of FIG. When the grinding is repeatedly performed using the CBN electrodeposition grindstone, the surface roughness Ra of the ground work material and the first signal intensity SP1 (vibration of the first wavelength band B1 with respect to the number of grinding processes, that is, the number of cuts It is a figure which shows the transition of the value of intensity integrated value. When the grinding is repeatedly performed using the CBN electrodeposition grindstone, the drive power waveform of the motor that drives the grinding wheel 14 and the first signal strength SP1 (vibration strength integration) of the first wavelength band B1 for each grinding process, that is, for each cut. It is a figure showing a value, a ● mark, and surface roughness Ra (a mark). 3 is a flowchart illustrating a main part of control operation by the arithmetic and control unit and the grinding control unit of FIG. 1 during grinding. 9 is a flowchart illustrating another example of the main part of the control operation by the arithmetic control device and the grinding control device of FIG. 1 during grinding. 9 is a flowchart illustrating another example of the main part of the control operation by the arithmetic control device and the grinding control device of FIG. 1 during grinding. 9 is a flowchart illustrating another example of the main part of the control operation by the arithmetic control device and the grinding control device of FIG. 1 during grinding. FIG. 34 is a diagram showing a change in the signal strength ratio SR when dressing is performed by the dressing control unit of FIG. 1 according to the dressing control start command of FIG. 33. 9 is a flowchart illustrating another example of the main part of the control operation by the arithmetic control device and the grinding control device of FIG. 1 during grinding. FIG. 9 is a diagram showing a machining number and a cumulative value SP2R of the second signal strength when a threshold is set for the cumulative value of the second signal strength SP2, a dressing control start instruction is issued, and dressing is performed by the dressing control unit. 9 is a flowchart illustrating another example of a main part of control operation by the arithmetic control device and the grinding control device of FIG. 1 during dressing. When the CBN vitrified grindstone is dressed using a rotary dresser, the actual signal strength ratio SR when the signal strength ratio SR is automatically controlled to be the target value 0.55, and the signal strength when not automatically controlled It is a polygonal line graph shown contrasting with ratio SR. 9 is a flowchart illustrating another example of a main part of control operation by the arithmetic control device and the grinding control device of FIG. 1 during dressing. 9 is a flowchart illustrating another example of a main part of control operation by the arithmetic control device and the grinding control device of FIG. 1 during dressing.

  An embodiment of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a grinding device 12 that also functions as a dressing device, including a grinding surface condition evaluation device 10 that also functions as a dressing surface condition evaluation device according to an embodiment of the present invention. The grinding surface state evaluation device 10 also functions as a dressing surface state evaluation device. The grinding apparatus 12 includes general abrasive grains such as fused alumina-based abrasive grains, silicon carbide-based abrasive grains, and ceramics abrasive grains, CBN abrasive grains, superabrasive grains such as diamond abrasive grains, and the like, vitrified grindstone, resinoid grindstone. Grinding wheels such as a metal bond grindstone and an electrodeposition grindstone are used. In this embodiment, the grinding wheel 14 shown in FIG. 1 is used as the grinding wheel. The grinding wheel 14 has a grindstone portion 16 fixed to a cylindrical or drum-shaped metal core, that is, an outer peripheral surface of the main body 18, and is attached to a rotary shaft that is rotationally driven by a main shaft drive motor 62. The grinding wheel 14 is driven at a relatively high peripheral speed of, for example, about 80 m / sec or more, and grinds the surface of the columnar work material 44, for example. In this embodiment, the grinding wheel 14 corresponds to a vitrified grindstone.

  The grinding surface state evaluation device 10 is provided in the main body 18, and when included in the grindstone portion 16, vibration generated at the grinding portion of the grinding wheel 14 at the time of crushing abrasive grains and propagating in the grindstone portion 16 is, for example, over 20 kHz. An AE sensor 22 that detects a crushing sound having an extremely high frequency in the sound wave region, that is, an AE signal wave (acoustic emission signal) from the inner peripheral surface of the grindstone portion 16 and outputs an AE signal SAE that is an analog signal representing the crushing sound. , A preamplifier 24 for amplifying the AE signal SAE output from the AE sensor 22, a transmission circuit 26 for transmitting the AE signal SAE amplified by the preamplifier 24 using a predetermined carrier, and a transmission circuit 26 for transmitting the AE signal SAE. Receiving circuit 30 having an antenna 28 for receiving the AE signal SAE, and a receiving circuit A bandpass filter 32 having a predetermined frequency band that allows the carrier wave received by 30 to pass therethrough, an A / D converter 34 that converts the AE signal SAE demodulated from the carrier wave into a digital signal, and a digital signal that is converted into the digital signal. And an arithmetic and control unit 36 for processing the AE signal SAE. The AE sensor 22, the preamplifier 24, and the transmission circuit 26 described above are provided in the main body 18 of the grinding wheel 14. The A / D converter 34 has a high resolution and has a sampling period of 10 μsec (microsecond) or less, preferably 5 μsec or less, and more preferably 1 μsec or less, and the AE signal SAE. To a digital signal. As the sampling cycle of the A / D converter 34 becomes shorter (higher speed), for example, as shown in FIGS. 5 to 7 to be described later, the first wavelength band B1 associated with spillage (bond crushing) and the crushing (abrasive grains). The second wavelength band B2 associated with (crushing) becomes clear. In the following embodiments, 1 μsec is used as the sampling cycle of the A / D converter 34.

  As shown in FIG. 2, for example, the grindstone portion 16 is composed of a well-known vitrified grindstone structure composed of abrasive grains 38, an inorganic binder (vitrified bond) 40 that binds the abrasive grains 38, and pores 42. By the sliding contact with the work material (work) 44 or the dresser 46, the first vibration caused by the generation of the crack A of the abrasive grain 38, that is, the crushing, the contact with the abrasive grain 38, and the work material 44. That is, the second vibration derived from the frictional vibration or the elastic vibration generated by the rubbing B is generated, and the grinding sound including the first vibration and the second vibration, that is, the AE signal wave is detected by the AE sensor 22.

  The arithmetic and control unit 36 of FIG. 1 is a so-called microcomputer including a CPU, a ROM, a RAM, an interface, etc., and the CPU processes an input signal according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM. By doing so, a numerical value, a graph, a graphic or the like representing the grinding surface condition for determining the dressing surface condition is calculated and output from the surface condition display device 48 which also functions as the grinding surface condition display device, and the grinding control device is also provided. Send to 72.

  The arithmetic and control unit 36 of the grinding surface state evaluation device 10 functionally includes a frequency analysis unit 50, a grinding surface state output unit 51, and a dressing surface state output unit 52. The frequency analysis unit 50 performs frequency analysis (FFT) of the AE signal SAE input from the A / D converter 34 during the grinding of the work material 44 or the dressing of the grinding wheel 14 to indicate the signal power. In the two-dimensional coordinates of the vertical axis and the horizontal axis showing the frequency, various signal powers showing the magnitude of the frequency component are generated for each frequency as peak waveforms to generate a power spectrum shown on the frequency axis (horizontal axis).

  The ground surface state output unit 51, during the grinding process of the work material 44, has a preset first wavelength band B1 including, for example, 32.5 kHz in the center portion from the power spectrum, for example, a first wavelength of 25 to 40 kHz. The first signal strength SP1 for the band B1 and the second signal strength SP2 for the second wavelength band B2 set in advance including, for example, 55 kHz in the center, for example, the second wavelength band B2 of 45 to 65 kHz are calculated. To do. The first signal strength SP1 and the second signal strength SP2 may be instantaneous values, but in order to stably grasp the blind spots and the eye spots, the first signal strength SP1 and the second signal strength SP2 are preferably stored in the A / D converter 34. An integral value or a moving average value within a predetermined period which is set sufficiently longer than the sampling period is used.

  In addition, the dressing surface state output unit 52 is preset during the dressing of the grinding wheel 14 using the dresser 46, similarly to the grinding surface state output unit 51, from the above power spectrum, including 32.5 kHz in the center. A first signal strength SP1 for a first wavelength band B1, for example a first wavelength band B1 of 25 to 40 kHz, and a preset second wavelength band B2 containing 55 kHz in the center, for example a second wavelength of 45 to 65 kHz. The second signal strength SP2 for the band B2 is calculated. The first signal strength SP1 and the second signal strength SP2 may be instantaneous values, but in order to stably grasp the blind spots and the eye spots, the first signal strength SP1 and the second signal strength SP2 are preferably stored in the A / D converter 34. An integral value or a moving average value within a predetermined period which is set sufficiently longer than the sampling period is used.

  At least the first signal strength SP1 and the second signal strength SP2 are output by the grinding surface state output unit 51 during grinding of the work material 44, or by the dressing surface state output unit 52 during dressing of the grinding wheel 14, respectively. Based on one of them, a dressing surface state evaluation value, for example, a related value (for example, a level value) related to an integral value or a moving average value of the signal strength in a predetermined cycle, or a signal strength ratio SR (= SP1 / SP2) or its related value ( For example, a level value) is calculated and output to the surface state display device 48. As a result, as shown in FIGS. 3 to 5, at least one of the first signal strength SP1 and the second signal strength SP2, the signal strength ratio SR or a related value thereof is used as the grinding surface condition evaluation value or the dressing surface condition. It is displayed on the surface state display device 48 as an evaluation value. When one of the first signal strength SP1 and the second signal strength SP2 is used, the grinding surface state evaluation value or the dressing surface evaluation value is the signal strength value of one of the first signal strength SP1 and the second signal strength SP2. It may be itself, or may be an index value that is easy to grasp, for example, a value converted into a level value.

  Here, in the power spectrum obtained by frequency analysis of the SAE signal converted from the AE signal wave detected by the AE sensor 22 into a digital signal using the high-speed and high-resolution A / D converter 34, the first wavelength band With respect to the generation of the peak waveform signal group in B1 and the peak waveform signal group in the second wavelength band B2, a grinding test conducted by the present inventor for various grinding wheels will be described below. Grinding test 1 includes a first wavelength band B1 composed of a peak waveform signal group and a first wavelength band B1 composed of a peak waveform signal group in a power spectrum obtained when grinding two types of electrodeposition grindstones and a resinoid grindstone, and a power spectrum obtained when dressing a resinoid grindstone. It is a verification test of the generation state of the two-wavelength band B2. The grinding test 2 is a verification test of the generation state of the first wavelength band B1 and the second wavelength band B2 formed by the peak waveform signal group in the power spectrum obtained at the time of grinding and dressing the vitrified grindstone.

(Test 1)
In order to confirm the occurrence of the first wavelength band B1 and the second wavelength band B2, grinding and dressing were performed under the following conditions. The following grinding tools show the specifications of the grindstone part attached to the grinding wheel with the built-in AE sensor.
Grinding tool: CBN electrodeposition grindstone CB 80 P 400φ × 30t
Diamond electrodeposition grindstone SD 80 P 400φ × 30t
CBN resinoid grindstone CB 170 P 75 B
Work Material: Ceramic Plate 1mmt
Dressing tool: Rotary dresser SD 40 Q M 100φ × 1.5W
Peripheral speed of grinding tool: 1250m / min
Peripheral speed of dresser: 864m / min
Depth of cut: Grinding tool 200 μm (1.2 mm / min)
Dresser φ0.002mm / pass
Dress lead: 0.15 mm / r. o. w.

  FIGS. 3, 4 and 5 show power spectra obtained from AE signal waves generated when a diamond electrodeposition grindstone, a CBN electrodeposition grindstone, and a CBN resinoid grindstone grind a ceramic plate. FIG. 6 shows a power spectrum obtained from an AE signal wave generated when a CBN resinoid grindstone was dressed by a rotary dresser. In FIGS. 3, 4 and 5, there are a first wavelength band B1 of 25 to 35 Hz, 25 to 40 Hz, 20 to 35 Hz, and a second wavelength band B2 of 45 to 65 Hz, 45 to 65 Hz, 40 to 60 Hz. is doing. Further, in FIG. 6, a first wavelength band B1 of 20 to 35 Hz and a second wavelength band B2 of 40 to 60 Hz are present as in FIG. At the time of dressing the resinoid grindstone shown in FIG. 6, the intensity of the peak waveform signal group in the first wavelength band B1 is higher than that at the time of grinding the resinoid grindstone shown in FIG. From this, it is estimated that the CBN abrasive grains are more crushed during dressing as compared with during grinding.

(Test 2)
7, FIG. 8 and FIG. 9 show the dressing test of three types of vitrified grinding wheels with different peripheral speed ratios Vd / Vg under the following dressing conditions (down cut of Vd / Vg = 1.0, Vd / Vg = 1.0). It is a figure which respectively shows the power spectrum obtained by the down cut of Vg = 0.3 and the up cut of Vd / Vg = 1.0. In addition, in FIG. 10, a predetermined determination threshold value for determining the occurrence of each peak waveform is provided for each peak waveform of the three types of power spectra, and the generated peak waveforms that exceed the determination threshold value are generated. It is a figure which shows the generation | occurrence | production map determined with it.

(Dressing conditions)
Grinding wheel: Grinding wheel with AE sensor Grinding wheel Grinding wheel part: CB 80 N 200 V (CBN abrasive grains of grain size 80 are bonded by vitrified bonding material, and have bonding degree N and concentration 200)
Grinding machine: General-purpose cylindrical grinder Grinding wheel peripheral speed Vg: 45 m / sec (clockwise)
Dresser: Rotary dresser Peripheral speed of dresser Vd: 45 m / sec (counterclockwise down cut) Peripheral speed ratio Vd / Vg = 1.0
・ Vd: 13.5 m / sec (counterclockwise down cut) peripheral speed ratio Vd / Vg = 0.3
・ Vd: 22.5 m / sec (counterclockwise down cut) peripheral speed ratio Vd / Vg = 0.5
・ Vd: 45 m / sec (clockwise up cut) Peripheral speed ratio Vd / Vg = 1.0

  FIG. 7 shows the power spectrum obtained under the dressing conditions under the downcut of Vd / Vg = 1.0. As shown in FIG. 1, the dressing condition of FIG. 7 is that the peripheral speed Vg of the clockwise grinding wheel and the peripheral speed Vd of the counterclockwise rotary dresser coincide with each other in the opposite rotational directions, and the contact point In the dressing conditions in which the relative peripheral speed between the grinding wheel and the rotary dresser is zero, and the crushing of the inorganic binder 40 of the vitrified grindstone is remarkable. In the power spectrum of FIG. 7, a plurality of peak waveforms are intensively generated in the first wavelength band B1 of 25 to 40 kHz and the second wavelength band B2 of 45 to 65 kHz, excluding low-frequency noise such as mechanical vibration. However, it was observed that the height of the peak waveform (signal intensity) in the first wavelength band B1 was larger than the height of the peak waveform (signal intensity) in the second wavelength band B2.

  FIG. 8 shows dressing conditions under downcut of Vd / Vg = 0.3, that is, the peripheral speed Vg of the grinding wheel is in the direction of rotation opposite to that of the peripheral speed Vd of the rotary dresser, but is about three times, which is exclusively for the vitrified grindstone. The power spectrum obtained under the dressing conditions in which the crushing of the abrasive grains is remarkable is shown. Also in this power spectrum, a plurality of peak waveforms are intensively generated in the first wavelength band B1 of 25 to 40 kHz and the second wavelength band B2 of 45 to 65 kHz, excluding low-frequency noise such as mechanical vibration. It was observed that the height of the peak waveform (signal intensity) in the second wavelength band B2 was larger than the height of the peak waveform (signal intensity) in the first wavelength band B1.

  FIG. 9 shows dressing conditions under upcut of Vd / Vg = 1.0, that is, the peripheral speed Vg of the grinding wheel is the same as the peripheral speed Vd of the rotary dresser, but in the reverse rotation direction to the case of FIG. 7, it is exclusively vitrified. The power spectrum obtained under the dressing condition where the crushing of the abrasive grains of the grindstone is remarkable is shown. Also in this power spectrum, a plurality of peak waveforms are intensively generated in the first wavelength band B1 of 25 to 40 kHz and the second wavelength band B2 of 45 to 65 kHz, excluding low-frequency noise such as mechanical vibration. It was observed that the height of the peak waveform (signal intensity) in the second wavelength band B2 was larger than the height of the peak waveform (signal intensity) in the first wavelength band B1.

  FIG. 10 shows a predetermined determination for determining the occurrence of each peak value for each peak value of the three types of power spectra having different peripheral speed ratios Vd / Vg shown in FIGS. 7, 8 and 9, respectively. FIG. 11 is a diagram showing a peak waveform generation map in which a threshold value is provided and a peak value that exceeds the determination threshold value is determined to have occurred and is shown in a black region. According to this FIG. 10, the peak value of the magnitude exceeding the determination threshold value occurs exclusively in the first wavelength band B1 of 25 to 40 kHz when the peripheral speed ratio Vd / Vg is downcut of 1.0, and the peripheral speed is The downcut with the ratio Vd / Vg of 0.3 and the upcut with the peripheral speed ratio Vd / Vg of 1.0 occur in the second wavelength band B2 of 45 to 65 kHz. Thereby, in the power spectrum obtained by frequency-analyzing the AE signal SAE, the height (signal intensity) of the peak waveform of at least a part of the wavelengths in the first wavelength band B1 reflects the crushing of the abrasive grains 38 on the surface of the vitrified grindstone. , The height (signal intensity) of the peak waveform of at least a part of the wavelength in the second wavelength band B2 reflects the frictional vibration or elastic vibration generated by the contact between the abrasive grains on the surface of the vitrified grindstone and the rotary dresser. Was confirmed. That is, the first wavelength band B1 corresponds to the bond crushing frequency band, and the second wavelength band B2 corresponds to the abrasive crushing frequency band.

  FIG. 11 shows the first signal strength SP1 (vibration strength integration) for the first wavelength band B1 obtained under the four dressing conditions in which the rotary direction and the peripheral speed ratio of the rotary dresser are different in the dressing test of the above-described test 2. Value), the second signal strength SP2 (vibration strength integrated value) for the second wavelength band B2, and the signal strength ratio SR (= SP1 / SP2). Generally, in the down-cut where the peripheral velocity ratio Vd / Vg is 1, the tangential relative velocity is 0, so that the abrasive grains 38 are crushed more often than attrited, and the dressing is performed in this state. From the empirical rule, it is known that in the grinding process using a grindstone, the sharpness improves and thus the power consumption decreases and the finished surface roughness deteriorates (the grindstone acts softly). Looking at the transition of the first signal strength SP1 in FIG. 11 above, when the downcut and the peripheral speed ratio Vd / Vg become 1, it rapidly increases. Therefore, the first signal strength SP1 or the signal strength ratio SR (SP1 / SP2), it is considered possible to detect an increase in the crushing of the abrasive grains 38. By monitoring the first signal strength SP1 or the signal strength ratio (SP1 / SP2), the completion of dressing can be quantitatively determined.

(Test 3)
In order to confirm the factors causing the first wavelength band B1 and the second wavelength band B2, grinding and dressing were performed under the following conditions.
Grinding tool: CBN vitrified grindstone CB 80N 200 V (400 mmφ x 30 mmt)
CBN electroplated whetstone CB 80 P (400 mmφ x 30 mmt)
Grinding method: Plunge grinding Grinding tool peripheral speed: 45 m / sec. (2122 rpm)
Work Material: SCM435 (Quenched) (50 mmφ x 10 mmt)
Peripheral speed of work material: 0.45 m / sec.
Cutting speed: R0.8mm / min
Cutting allowance: Depth of cut R1.04 mm (workpiece diameter before processing 50 mmφ) Equivalent to 160 mm ^{2 in} grinding allowance cross section Sparkout: 10 rev.
Grinding oil: SEC700 (× 50)
Flow rate: 20 L / min
Dressing tool: Rotary dresser SD 40 Q 75 M (100mmφ × 1U)
Dress peripheral speed: Vw = 45 m / s, Vd = 13.5 m / s (Vd / Vw = 0.3)
Dress lead: 0.10 m / r. o. w.
Dress depth: R0.002mm / pass × 10pass
* CBN vitrified grindstone only for dressing

  12 and 13 respectively show power spectra obtained from AE signal waves generated when the CBN vitrified grindstone and the CBN electrodeposited grindstone grind the work material SCM435 (quenched). In the power spectrum of the CBN electrodeposited grindstone shown in FIG. 13, similar to the power spectrum of the CBN vitrified grindstone shown in FIG. 12, there is a first wavelength band B1 of 30 to 40 Hz and a second wavelength band B2 of 45 to 65 Hz. ing. 6 shows a power spectrum obtained from an AE signal wave generated when dressed by a rotary dresser. The peak waveform signal group in the first wavelength band B1 is considered to be derived from crushing of the abrasive grains. However, since the peak waveform signal group of the second wavelength band B2 is also generated in the CBN electrodeposition grindstone in which the abrasive grains are bonded by the metal (nickel plating), it is considered that the peak waveform signal group does not originate from the crush of the bond. ..

In FIG. 14, the horizontal axis represents the number of cuts (the number of times of grinding) in which grinding was performed repeatedly under the conditions of the grinding test 2 with the CBN electrodeposition grindstone, and the first signal intensity SP1 (vibration intensity integrated value) and the first wavelength intensity B1 for the first wavelength band B1 and In the two-dimensional coordinates with the cumulative number of crushed abrasive grains per unit area (grains / mm ² ) as the vertical axis, the first signal intensity SP1 (vibration intensity) obtained from the first wavelength band B1 generated when grinding the CBN electrodeposition grindstone. It is a graph which shows a change of the integrated value) and the cumulative number of crushed abrasive grains (grain / mm ² ) per unit area of the CBN electrodeposition grindstone. The cumulative number of crushed abrasive grains per unit area (grains / mm ² ) was crushed by a two-stage replica from an SEM photograph (10 kv 0.5 mm × 50 2.4 mm × 1.8 mm) of the ground surface of the CBN electrodeposition grindstone. It was calculated using the abrasive quantification method.

  In FIG. 14, the cumulative number of crushed abrasive grains on the grinding surface of the CBN electrodeposition grindstone increases with the increase in the number of cuts, and converges after the number of cuts reaches a predetermined value (150 cuts). However, the first signal strength SP1 (vibration strength integrated value) is relatively constant regardless of the increase in the number of cuts, but a vibration peak frequently occurs until the number of cuts reaches a predetermined value (about 150 cuts), After the number of cuts reached a predetermined value (about 150 cuts), the vibration peak subsided and became stable. From this, it is considered that the peak waveform signal group in the first wavelength band B1 is derived from the crushing of the abrasive grains.

  In FIG. 15, the number of cuts (the number of times of grinding) that has been repeatedly ground under the conditions of the grinding test 2 is taken as the horizontal axis, and the second signal strength SP2 (vibration strength integrated value) and the working area of the abrasive grains for the second wavelength band B2 are shown. In the two-dimensional coordinates with the rate (%) as the vertical axis, the second signal intensity SP2 (vibration intensity integrated value) obtained from the second wavelength band B2 generated during grinding of the CBN electrodeposition grindstone, and the grinding of the CBN electrodeposition grindstone It is a graph which shows the change of the active area rate (%) of a grain. The active area ratio (%) of the abrasive grains is within the range of 10 μm from the tip of the abrasive grains by searching the abrasive grains with the highest protrusion from the 3D shape measurement result of the laser microscope which measures the ground surface of the CBN electrodeposition grindstone. The cross-sectional area of the abrasive grains in was calculated, and the ratio was calculated from the cross-sectional area.

  In FIG. 15, the second signal intensity SP2 (vibration intensity integrated value) obtained from the second wavelength band B2 generated when grinding the CBN electrodeposition grindstone, and the working area ratio (%) of the abrasive grains of the CBN electrodeposition grindstone are: Both increase with the increase in the number of cuts, and after the number of cuts reaches a predetermined value (about 230 cuts), after both decrease, the reduction stops. From this, the peak waveform signal group in the second wavelength band B2 is proportional to the working area of the abrasive grains with respect to the work material, and the frictional vibration generated by the contact (sliding contact) between the abrasive grains and the work material or It is considered to be derived from elastic vibration.

  FIG. 16 shows a case where the CBN vitrified grindstone was used to repeatedly grind under four different processing conditions 1 to 4 using the conditions of the grinding test 2 except that the peripheral speed of the grinding tool, the cutting speed, and the material of the work material were different. 11 is a bar graph showing the magnitude of the vibration intensity ratio (SP1 / SP2) obtained as an average value of 11 to 14 cuts of FIG. Compared to machining condition 1 in which the peripheral speed of the grinding tool is 2700 m / min, the cutting speed is R0.8 mm / min, and the material of the work material is SCM435, the peripheral speed of the grinding tool is 1500 m / min and the cutting speed is R0. 8 mm / min, machining condition 2 in which the work material is SCM435, peripheral speed of the grinding tool is 2700 m / min, cutting speed is R2.8 mm / min, machining condition 3 in which the work material is SCM435, grinding The magnitude of the vibration intensity ratio (SP1 / SP2) increases as the machining condition 4 in which the peripheral speed of the tool is 2700 m / min, the cutting speed is R0.8 mm / min, and the material of the work material is SUS304. Condition 2 and condition 3 have the same cutting load on the abrasive grains, but it is considered that the cutting speed has a larger effect than the peripheral speed. Further, the increase rate of the vibration intensity ratio (SP1 / SP2) of the condition 4 is larger than that of the condition 3. It is considered that this is because the work material is a difficult-to-cut material, and therefore the abrasive grains are largely removed even when the cutting speed is reduced.

  17, FIG. 18, FIG. 19, and FIG. 20 are 3D maps obtained by measuring the ground surface of the CBN vitrified grindstone with a laser microscope after cutting under the conditions 1, 2, 3, and 4 in FIG. The black portion indicates the part where the abrasive grains have fallen off. As is clear from these 3D maps, the larger the vibration intensity ratio (SP1 / SP2) is, the more the abrasive grains fall off.

(Test 4)
Next, the present inventor will perform the grinding test under the following two grinding processing conditions with different cutting speeds, and will explain the results of the grinding test. FIG. 21 shows a power spectrum when the cutting speed is R 0.8 mm / min and the grinding efficiency is low. FIG. 22 shows the power spectrum when the cutting speed is R2.8 mm / min and the grinding efficiency is high.

(Grinding conditions)
Grinding wheel: Grinding wheel with AE sensor Grinding wheel Grinding wheel part: CB 80 N 200 V (CBN abrasive grains of grain size 80 are bound by vitrified binding material, and have binding degree N and concentration degree 200)
Grinding machine: General-purpose cylindrical grinding machine Grinding method: Wet plunge grinding Grinding wheel peripheral speed Vg: 45 m / sec Work material: SCM435 quenching (HRc48 ± 2)
Peripheral speed of work material: 0.45 m / sec Cutting allowance: Depth of cut R1.04 mm (workpiece diameter before processing 50 mmφ), grinding allowance equivalent to 160 mm ² Cutting speed: R0.8 mm / min, R2 .8 mm / min Spark Out: 10 rev.
Grinding fluid: Noritake Cool SEC700 (× 50)
Grinding liquid flow rate: 20 L / min

  FIG. 21 shows the second wavelength band B2 corresponding to the frictional vibration or elastic vibration generated by the contact between the abrasive grains and the work material in the low-efficiency machining with the machining efficiency (cutting speed) of R 0.8 mm / min. The signal intensity of is larger than the signal intensity of the first wavelength band B1 corresponding to the crushing of the abrasive grains, and it indicates that the spilling (changing) is less likely to occur and the grinding process tends to be crushed. On the other hand, FIG. 22 shows that the signal intensity in the first wavelength band B1 is larger than the signal intensity in the second wavelength band B2 in the high-efficiency machining in which the grinding efficiency (cutting speed) is R2.8 mm / min. It is shown that the grinding process is less likely to cause crushing due to the crushing of the abrasive grains, and has a tendency to cause spillage (replacement) due to the crushing of the bond bridge.

  In the power spectrum of the low-efficiency machining (cutting speed R 0.8 mm / min) of FIG. 21, the signal intensity of the first wavelength band B1 is smaller than the signal intensity of the second wavelength band B2, and the crushing of the abrasive grains is small. Alternatively, since a large number of abrasive grains act on the work material and the load per grain is small, it is difficult for the grains to change, and the grinding process tends to be crushed. On the other hand, in the power spectrum in the high-efficiency machining (cutting speed R2.8 mm / min) of FIG. 22, the signal intensity of the first wavelength band B1 is larger than the signal intensity of the second wavelength band B2, and Due to the large number of crushed grains, there are many changes that occur and the grinding process tends to spill.

In FIG. 23, the signal strength in the first wavelength band B1, for example, its integrated value is the first signal strength SP1, and the signal strength in the second wavelength band B2, for example, its integrated value is the second signal strength SP2. Is SP1 / SP2, the horizontal cross-section represents the grinding allowance cross-sectional area S (mm ² / mm) per unit circumference length of the grinding wheel, and low efficiency machining with a tendency to cause clogging (cutting speed R0.8 mm / Minutes (indicated by ●) and high-efficiency processing with spilling tendency (cutting speed R 2.8 mm / min (indicated by ○)), and the signal intensity ratios obtained from the power spectra obtained respectively. SR is shown. This signal strength ratio SR (= SP1 / SP2) is a suitable grinding surface state evaluation value that can evaluate the balance between the blinded state and the spilled state. As shown in FIG. 23, when 0.6 or less is set as a blind state, low-efficiency processing (cutting speed R 0.8 mm / min (indicated by ●)) is performed by grinding per unit circumferential length of the grinding wheel. Although the cross sectional area S (mm ² / mm) shows a crushed state in the entire area, the signal intensity ratio SR is 0.6 in high efficiency machining (cutting speed R 0.8 mm / min (indicated by ◯)). It shows a spilled state. FIG. 24 is an enlarged view of a region where the grinding allowance cross-sectional area S (mm ² / mm) per unit circumferential length of the grinding wheel, which is the horizontal axis of FIG. 23, is 0 to 5.

  25 shows an example of a bar graph type level display displayed on a liquid crystal screen as one display mode of the surface state display device 48 of FIG. 1, and FIG. 26 shows one display mode of the surface state display device 48 of FIG. As an example, a level meter type display example displayed on a liquid crystal screen or an instrument is shown. Although both the first signal strength SP1 and the second signal strength SP2 are displayed in FIG. 25, one of them may be displayed as the evaluation value indicating the dressing surface state. In FIG. 26, the first signal strength SP1, the second signal strength SP2, and the signal strength ratio SR (= SP1 / SP2) are displayed, and one of them or the level value corresponding thereto is the ground surface. It may be displayed as an evaluation value indicating the state or the dressing surface state. The evaluation value indicating the state of the grinding surface or the state of the dressing surface is used in the manual control for manually adjusting the grinding condition or the dressing condition in the grinding processing device (dressing device) 12.

  In FIG. 25, the bar graph 54 showing the first signal intensity SP1 for the first wavelength band B1 associated with the crushing of the abrasive grains 38 is on the left side, and the second wavelength associated with the sliding contact between the abrasive grains 38 and the work material 44. A bar graph 56 showing the second signal strength SP2 for the band B2 is shown on the right side as a left and right pair. The crushed state can be evaluated based on the crushed state of the abrasive grains 38 in the first wavelength band B1 indicated by the bar graph 54 on the left side, and the abrasive grains 38 in the second wavelength band B2 indicated by the right side bar graph 56 and the work material. The eye spilled state can be evaluated based on the sliding contact state with 44. Further, the bar graphs 54 and 56 of FIG. 25 show the signal intensities of the respective wavelength bands divided into four in the first wavelength band B1 and the second wavelength band B2, so that the left and right bar graphs 54 and 56 are compared with each other. 25A shows whether the crushing strength of the abrasive grains 38 exceeds the strength of frictional vibration or elastic vibration caused by the contact between the abrasive grains 38 and the work material 44, as shown in FIG. In addition to the fact that it is possible to determine whether the crushing strength of the abrasive grains 38 shown in (b) is lower than that of frictional vibration or elastic vibration caused by the contact between the abrasive grains 38 and the work material 44, , Based on the crushing strength pattern in each of the first wavelength band B1 and the second wavelength band B2, the frictional vibration or elastic vibration state caused by the crushing of the abrasive grains 38 and the contact between the abrasive grains 38 and the work material 44 is accurately determined. Can be evaluated That.

  The display example of the surface state display device 48 of FIG. 26 is composed of a plurality of meter-type indicators 58, 59, 60 for indicating the scale using a needle. The display 58 shows the first signal intensity SP1 for the first wavelength band B1 associated with the crushing of the inorganic binder 40, and the display 59 shows the first signal intensity SP1 for the second wavelength band B2 associated with the crushing of the abrasive grains 38. 2 shows the signal strength SP2. The spilled state can be evaluated based on the crushing strength of the abrasive grains 38 in the first wavelength band B1 indicated by the display level of the indicator 58, and the abrasive grains in the second wavelength band B2 indicated by the display level of the indicator 60 can be evaluated. It is possible to evaluate the blindness state based on the intensity of frictional vibration or elastic vibration generated by the contact between the work piece 38 and the work material 44. Further, it is possible to more accurately evaluate the spilled state or the blunted state based on the comparison of the signal intensities in the first wavelength band B1 and the second wavelength band B2 indicated by the display levels of the indicators 58 and 59, respectively. it can. The display 60 displays the first signal intensity SP1 for the first wavelength band B1 associated with the crushing of the abrasive grains 38 and the second signal band SP2 for the second wavelength band B2 associated with the frictional state between the abrasive grains 38 and the work material 44. A signal intensity ratio SR (= SP1 / SP2) with the signal intensity SP2 is shown.

  Returning to FIG. 1, the grinding device 12 includes a spindle drive motor 62 that rotationally drives a spindle (not shown) to which the grinding wheel 14 is attached, and a work material rotation drive motor 64 that rotationally drives a cylindrical work material 44. A work material moving motor 66 for moving the work material 44 in the radial direction in order to press the grinding wheel 14 against the outer peripheral surface of the work material 44 having a cylindrical shape, and a dresser drive motor 68 for rotationally driving the dresser 46. A dresser feed motor 70 for feeding the dresser 46 in the direction of the rotation center line thereof and a grinding control device 72 are provided.

  The grinding control device 72 is composed of a microcomputer similar to the arithmetic and control unit 36, and functionally includes an automatic grinding control unit 74 and a dressing control unit 76. Upon receiving the grinding start command signal, the automatic grinding control unit 74 grinds the work material 44 by rotating the grinding wheel 14 and the work material 44 while rotating the grinding wheel 14 and the work material 44, respectively. When the grinding of the material 44 is completed, the rotation of the work material 44 is stopped and returned to the original position.

  The grinding automatic control unit 74, in the process of grinding the workpiece 44, actually outputs the first signal intensity SP1, the second signal intensity SP2, or the signal intensity ratio SR (= SP1) output from the dressing surface state output unit 52. / SP2), so that the grinding surface state indicated by the actual evaluation value for the work material 44 becomes the grinding surface state indicated by the preset target evaluation value, the spindle drive motor 62, the work material rotation drive motor. 64 and the work material movement motor 66 are automatically controlled. For example, the automatic grinding control unit 74 sets the target signal intensity ratio SRT to a value that provides a good balance between crushing and spillage, and the actual signal intensity ratio SR sequentially output from the dressing surface state output unit 52 in real time is, for example, The grinding conditions are automatically adjusted so as to match the target signal intensity ratio SRT preset to about 0.55. For example, when the actual signal intensity ratio SR exceeds a preset target signal intensity ratio SRT, there is a tendency for spilling. Therefore, in order to suppress the spilling, the machining efficiency (cutting speed) is lowered and grinding is performed. At least one of increasing the peripheral speed Vg of the wheel 14 (increasing the rotation speed) and decreasing the peripheral speed of the work material 44 is executed to change the actual signal strength ratio SR toward the target signal strength ratio SRT. Let On the contrary, when the actual signal intensity ratio SR is lower than the preset target signal intensity ratio SRT, there is a tendency for blind spots. Therefore, in order to suppress the blind spots, the machining efficiency (cutting speed) is increased. Then, at least one of the decrease of the peripheral speed Vg of the grinding wheel 14 (the decrease of the number of revolutions) and the increase of the peripheral speed of the work material 44 is executed to shift the actual signal strength ratio SR to the target signal strength ratio SRT. To change.

  The solid circles in FIG. 27 indicate the target signal strength ratio SRT (the actual signal strength ratio SR is set in advance when the target signal strength ratio SRT is set to 0.55 as a value with a good balance between blindness and spillage). = 0.55), an example of automatic grinding control by the automatic grinding control unit 74, which adjusts the grinding conditions so as to match the same, is shown. In this automatic grinding control, while the actual signal strength ratio SR shifts along the target signal strength ratio SRT as the number of machining increases, the automatic control shown by a circle in FIG. 27 is performed. The actual signal strength ratio SR when there is no deviation deviates from the target signal strength ratio SRT as the number of machining changes. The automatic grinding control by the automatic grinding control unit 74 is performed by the target first signal strength SP1T or target in which the actual first signal strength SP1 or the second signal strength SP2 is set to a value having a good balance between the blind spots and the blind spots. The grinding conditions may be adjusted so as to match the second signal strength SP2T.

When the actual second signal strength SP2 or the signal strength ratio SR reaches a preset dressing processing start condition, the dressing surface state output unit 52 outputs a command to the dressing control unit 76 to start dressing processing. The dressing start condition is that, for example, the cumulative value SP2R of the second signal intensity SP2 exceeds a threshold value, for example, 3 × 10 ^5, and the first signal intensity SP1 (vibration intensity integrated value) of the first wavelength band B1 exceeds the threshold value. That is, the fluctuation range exceeds the threshold value, or the signal strength ratio SR exceeds the threshold value, for example, 0.4.

  FIG. 28 shows changes in the surface roughness Ra of the ground material 44 and the first signal intensity SP1 (integrated value of vibration intensity) of the first wavelength band B1 with respect to the number of grinding processes, that is, the number of cuts. There is. The present inventor has found a predictive phenomenon of deterioration of surface roughness, in which the first signal strength SP1 sharply increases near the number of cuts 170, and immediately thereafter, the surface roughness Ra rapidly increases (deteriorates). Therefore, by using the dressing start processing condition using the first signal strength SP1 or the signal strength ratio SR including the first signal strength SP1, the grinding processing quality is preferably maintained. On the other hand, FIG. 29 shows, for each cut, the drive power waveform of the motor that drives the grinding wheel 14, the first signal strength SP1 (vibration strength integrated value, ●) of the first wavelength band B1, and the surface roughness. Ra (marked by Δ), the deterioration of the surface roughness Ra and the decrease of the driving power occur at the same time. Therefore, it is possible to set the dressing start condition that the drive current value is below the threshold value, but the dressing can be started only after the surface roughness Ra becomes large.

  When the dressing control unit 76 receives the dressing start command signal from the dressing surface state output unit 52, the grinding wheel 14 and the dresser 46 are rotationally driven and relatively moved by a preset operation, whereby the surface of the grinding wheel 14 is moved. When the dressing of the grinding wheel 14 is completed, the dresser 46 stops rotating and returns to its original position. In this preset operation, one cycle of operation is performed in which the grinding surface of the grinding wheel 14 is cut with a constant cutting amount. Alternatively, the cutting is performed by the automatic control described below.

  In the dressing process of the grinding wheel 14, the dressing control unit 76 sets the actual first signal strength SP1, second signal strength SP2, or signal strength ratio SR (= SP1 / SP2) output from the dressing surface state output unit 52. Based on this, the spindle drive motor 62, the dresser drive motor 68, and the dresser feed motor 70 are automatically controlled so that the grinding surface state indicated by the evaluation value of the grinding wheel 14 becomes the grinding surface state indicated by the preset target evaluation value. . For example, the dressing control unit 76 sets the target signal strength ratio SRT to a value with a good balance between blindness and spillage, and the actual signal strength ratio SR sequentially output from the dressing surface state output unit 52 in real time is 0, for example. The dressing condition is automatically adjusted so as to match the preset dress target signal intensity ratio DSRT of about 0.65.

  For example, when the actual signal intensity ratio SR exceeds the preset target signal intensity ratio SRT, there is a tendency for eye spillage. Therefore, in order to suppress the eye spillage, the feed speed of the dresser 46 is reduced (dress lead is reduced). When the rotation direction of the grinding wheel 14 and the dresser 46 is the downcut direction, the peripheral speed Vg of the grinding wheel 14 or the dresser 46 is set so that the peripheral speed ratio Vd / Vg of the dresser 46 and the grinding wheel 14 is moved away from 1. At least one of the adjustments of the peripheral speed Vg is executed to change the actual signal strength ratio SR toward the dress target signal strength ratio DSRT. On the contrary, when the actual signal strength ratio SR is lower than the preset dress target signal strength ratio DSRT, there is a tendency to be blind, so in order to suppress the blindness, the feed speed of the dresser 46 is increased ( When the rotation direction of the grinding wheel 14 and the dresser 46 is the down-cut direction, the peripheral speed Vg of the grinding wheel 14 or the peripheral speed Vg of the grinding wheel 14 is set so that the peripheral speed ratio Vd / Vg of the dresser 46 and the grinding wheel 14 approaches 1. At least one of the adjustments of the peripheral speed Vd of the dresser 46 is executed to change the actual signal strength ratio SR toward the dress target signal strength ratio DSRT.

  FIG. 30 is a flowchart for explaining a main part of the control operation of the arithmetic and control unit 36 and the grinding control unit 72 during grinding, which is repeatedly executed at a predetermined control cycle. 30, in step S1 (hereinafter, steps are omitted), the AE signal SAE converted into a digital signal output from the A / D converter 34 is sequentially obtained while the work material 44 is being ground by the grinding wheel 14. Is read. Next, in S2 corresponding to the frequency analysis unit 50, frequency analysis (FFT analysis) is performed, and the power spectrum of the AE signal SAE is generated. Then, S3, S4, S5, and S6 corresponding to the grinding surface state output unit 51 are executed.

  In S3, the first signal strength SP1 which is an integrated value of the signal strength in the abrasive grain crushing frequency band of the AE signal SAE, that is, in the first wavelength band B1 is calculated. In S4, the second signal intensity SP2, which is the integrated value of the signal intensity in the contact frequency band of the abrasive grains and the work material, that is, the second wavelength band B2 of the AE signal SAE is calculated. In S5, the signal strength ratio SR (= SP1 / SP2), which is the ratio of the first signal strength SP1 and the second signal strength SP2, is calculated in real time. Then, in S6, the signal intensity ratio SR calculated in S5 is output (transmitted) to the automatic grinding control unit 74 of the grinding control device 72 as an evaluation value representing the state of the grinding surface.

  In S7 corresponding to the grinding automatic control unit 74, the signal strength ratio SR (= SP1 / SP2), which is the actual evaluation value output from the grinding surface state output unit 51, becomes a well-balanced value of the blind spots and the blind spots. The machining efficiency (cutting speed) Z, the peripheral speed of the grinding wheel 14, the peripheral speed of the work material 44, and the work material 44 are increased so as to match the target signal intensity ratio SRT which is a preset target evaluation value. The grinding condition is automatically adjusted by changing at least one of the feed rates of the above.

  FIG. 31 is a flowchart illustrating an example of another control operation of the arithmetic and control unit 36 during grinding. The flowchart shown in FIG. 31 includes S8 to be displayed on the surface state display device 48, instead of S6 and S7 of the flowchart of FIG. In this embodiment, the actual signal intensity ratio SR is sequentially displayed on the surface state display device 48, so that the grinding conditions in the grinding control device 72 can be manually controlled.

  FIG. 32 is a flowchart illustrating another example of the control operation of the arithmetic and control unit 36 and the grinding control unit 72 during grinding. The flowchart shown in FIG. 32 is obtained by deleting S4 and S5 in the flowchart of FIG. In this embodiment, in S7 corresponding to the automatic grinding control unit 74 of the grinding control device 72, the grinding conditions are automatically controlled so that the actual first signal strength SP1 matches the preset target first signal strength SP1T. To be done.

  FIG. 33 is a flowchart illustrating another example of the control operation of the arithmetic and control unit 36 and the grinding control unit 72. In the flowchart shown in FIG. 33, instead of S6 and S7 in the flowchart of FIG. 30, the signal intensity ratio SR calculated in S5 is a preset dressing start threshold value, preferably dressing is required due to progress of blindness. And S10 corresponding to the dressing controller 76 that starts dressing of the grinding wheel 14 when the determination in S9 is affirmative. There is. FIG. 34 is a graph showing the signal strength ratio SR changed by the control of FIG. It is shown that the grinding surface of the grinding wheel 14 is sharpened from the crushed state by the dressing performed every time the signal intensity ratio SR falls below a threshold value, for example, 0.4.

FIG. 35 is a flowchart illustrating another example of the control operation of the arithmetic and control unit 36 and the grinding control unit 72 during grinding. The flowchart shown in FIG. 35 is changed from S3 and S5 of the flowchart of FIG. 30 to S7, and S11 for sequentially calculating the cumulative signal strength SP2R obtained by accumulating the second signal strength SP2 calculated at S4, and calculated at S11. The cumulative signal strength SP2R is determined whether it exceeds a preset dressing start threshold, preferably a threshold required for dressing due to progress of blindness, for example, 3 × 10 ⁵ , and the determination of S12. If affirmative, S10 corresponding to the dressing control unit 76 that starts dressing of the grinding wheel 14 is provided. FIG. 36 shows a method of setting a threshold value on the cumulative signal strength SP2R obtained by accumulating the second signal strength SP2, automatically performing dressing when the threshold value is exceeded, and resetting the cumulative signal strength SP2R to 0 after the dressing is completed. , Is a graph showing the transition of SP2R with the progress of the number of cuts.

  FIG. 37 is a flowchart illustrating another example of the control operation of the arithmetic and control unit 36 and the grinding control unit 72 during dressing. The flowchart shown in FIG. 37 is replaced with S1 of the flowchart of FIG. 30, and during dressing of the grinding surface of the grinding wheel 14 by the dresser 46, the AE signal SAE converted into the digital signal output from the A / D converter 34. Is sequentially read, and S22 corresponding to the dressing control unit 76 is provided instead of S7 in the flowchart of FIG. In S22, for example, as shown in FIG. 38, the dress lead, the peripheral speed ratio, etc. are set so that the signal strength ratio SR, which is the actual evaluation value, becomes the target signal strength ratio SRT, which is the preset target evaluation value. Sequentially execute automatic control for adjusting dressing conditions.

  FIG. 39 is a flowchart illustrating another example of the control operation of the arithmetic and control unit 36 during dressing. The flowchart shown in FIG. 39 is replaced with S1 of the flowchart of FIG. 30, and during dressing of the grinding surface of the grinding wheel 14 by the dresser 46, the AE signal SAE converted into the digital signal output from the A / D converter 34. Is sequentially read, and S23 corresponding to the dressing surface state output unit 52 is provided instead of S6 and S7 in the flowchart of FIG. In S23, the actual signal strength ratio SR is compared with a preset target signal strength ratio SRT range, for example, 0.5 to 0.6, and if the actual signal strength ratio SR is within the target signal strength ratio SRT range. For example, the dressing is judged to be successful and the dressing is ended, but if the actual signal strength ratio SR is outside the range of the target signal strength ratio SRT, a dressing failure judgment is made and the dressing control unit 76 starts re-dressing. Command.

  FIG. 40 is a flowchart illustrating another example of the control operation of the arithmetic and control unit 36 during dressing. The flowchart shown in FIG. 40 is replaced with S1 of the flowchart of FIG. 30, and during dressing of the grinding surface of the grinding wheel 14 by the dresser 46, the AE signal SAE converted into the digital signal output from the A / D converter 34. Is sequentially read, and S24 corresponding to the dressing surface state output unit 52 is provided instead of S6 and S7 in the flowchart of FIG. In S24, the evaluation value indicating the ground surface state of the dressed grinding wheel 14, that is, the actual signal intensity ratio SR is displayed on the surface state display device 48.

  As described above, according to the grinding surface state evaluation device 10 of the present embodiment, the grinding surface state evaluation device 10 for evaluating the grinding surface state of the grinding wheel 14 that grinds the work piece 44 is a grinding wheel. 14, an AE sensor 22 that detects the vibration generated and outputs an AE signal, (c) an A / D converter 34 that converts the AE signal output from the AE sensor 22 into a digital signal, and an A / D converter A frequency analysis unit 50 that obtains a power spectrum by frequency-analyzing the AE signal converted into a digital signal by 34, and is related to the crushing of the abrasive grains 38 of the grinding wheel 14 in the power spectrum obtained by the frequency analysis unit 50. The first signal intensity SP1 of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2 related to the contact between the abrasive grains 38 of the grinding wheel 14 and the work material 44 are small. One of them is calculated, and an evaluation value related to the grinding surface state of the grinding wheel 14 is output based on at least one of the first signal intensity SP1 of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2. And the grinding surface state output unit 51.

  By doing so, the evaluation value representing the grinding surface state calculated based on the first signal intensity SP1 of the first wavelength band B1 associated with the crushing of the abrasive grains 38 of the grindstone portion 16 of the grinding wheel 14 is the abrasive grains. It is a value indicating whether the crushed state of 38 is large or small, and the smaller the value, the more the progress of the crushed state of the grindstone portion 16 of the grinding wheel 14 is reflected. In addition, the evaluation value representing the grinding surface state calculated based on the second signal intensity SP2 of the second wavelength band B2 related to the contact between the abrasive grains 38 of the grindstone portion 16 of the grinding wheel 14 and the work material 44 is: It is a value indicating frictional vibration or elastic vibration generated by the contact between the abrasive grains 38 and the work material 44, and the smaller the value, the more the progress of the spilled state of the grinding wheel 14 is reflected. As a result, based on the first signal intensity SP1, the second signal intensity SP2, or the signal intensity ratio SR that is the evaluation value calculated by the grinding surface state output unit 51, the spilled state of the grinding wheel (vitrified grindstone) 14 is determined. Progression or progression of blindness can be assessed quantitatively.

  Further, according to the ground surface state evaluation device 10 of the present embodiment, at least one of the first signal intensity SP1 of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2 is an integrated value or a moving average value. The grinding surface state output unit 51 is based on at least one of the first signal intensity SP1 of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2. The evaluation value related to the ground surface state of the portion 16 is output. As described above, the grindstone portion of the grinding wheel (grinding grindstone) 14 is based on the integrated value or the moving average value of at least one of the first signal intensity SP1 of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2. Since the evaluation value related to the grinding surface state of 16 is output, the influence of the abnormal value is reduced, and therefore the progress of the blind state of the grindstone portion 16 of the grinding wheel 14 or the grindstone portion 16 of the grinding wheel 14 is increased. It is possible to accurately evaluate the progress of the spilled state.

  Further, according to the ground surface state evaluation device 10 of the present embodiment, the first signal intensity of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2 are integrated values or moving average values, and The surface state output unit 51 calculates the signal intensity ratio SR of the first signal intensity SP1 of the first wavelength band B1 and the second signal intensity SP2 of the second wavelength band B2, and calculates the signal intensity ratio SR of the grinding wheel 14 based on the signal intensity ratio SR. The evaluation value related to the grinding surface condition is output. As a result, the smaller the value, the more the first signal intensity SP1 of the first wavelength band B1 that reflects the progress of the blinded state of the grindstone portion 16 of the grinding wheel 14, and the smaller the value, the more the spilled state of the grinding wheel 14 progresses. By the signal intensity ratio SR (= SP1 / SP2) with the second signal intensity SP2 of the second wavelength band B2 which is reflected, the progress of the blind state and the progress of the spilled state of the grindstone portion 16 of the grinding wheel 14 are emphasized. Therefore, it is possible to accurately evaluate the progress of the blind state or the spilled state of the grindstone portion 16 of the grinding wheel 14.

  Further, according to the ground surface state evaluation device 10 of the present embodiment, the surface state display device 48 for displaying the evaluation value output from the ground surface state output unit 51 is provided. As a result, it is possible to accurately visually evaluate the progress of the blunted state and / or the spilled state of the grinding surface or the dressing surface of the grindstone portion 16 of the grinding wheel 14.

  Further, according to the ground surface state evaluation device 10 of the present embodiment, the first wavelength band B1 is a wavelength band of 25 to 40 kHz, and the second wavelength band B2 is a wavelength band of 45 to 65 kHz. Accordingly, the first signal intensity SP1 of the first wavelength band B1 corresponding to the progress of the blind state of the grindstone portion 16 of the grinding wheel 14 and / or the progress of the spilled state of the grindstone portion 16 of the grinding wheel 14 are dealt with. By using the second signal strength SP2 of the second wavelength band B2, the grinding surface state of the grinding wheel 14 can be quantitatively evaluated.

  Further, according to the ground surface state evaluation apparatus 10 of the present embodiment, the sampling cycle of the A / D converter 34 is 10 μsec or less, preferably 1 μsec or less. Thereby, the first signal intensity SP1 of the first wavelength band B1 reflecting the progress of the blind state of the grindstone portion 16 of the grinding wheel 14 and / or the progress of the spilled state of the grindstone portion 16 of the grinding wheel 14 are reflected. The second signal strength SP2 of the second wavelength band B2 is clearly obtained.

  Further, according to the grinding processing device 12 including the grinding surface state evaluation device 10 of the present embodiment, grinding is performed so that the actual evaluation value output from the grinding surface state output unit 51 becomes a preset target evaluation value. It includes an automatic grinding control unit 74 that adjusts at least one of the cutting speed of the wheel 14 into the work material 44, the peripheral speed of the grinding wheel 14, and the peripheral speed of the work material 44. As a result, the grinding conditions for the work material 44 of the grinding wheel 14 are automatically controlled appropriately, so that variations in the grinding quality of the work material 44 are suppressed.

  The grinding processing device 12 including the grinding surface state evaluation device 10 of the present embodiment grinds the workpiece 44 using the grinding wheel 14, and also includes a dressing control unit 76 that dresses the grinding wheel 14 using the dresser 46. When the evaluation value output from the grinding surface state output unit 51 becomes a preset dressing start condition, the grinding of the work material 44 using the grinding wheel 14 is stopped and the dressing operation by the dressing control unit 76 is stopped. The activation, that is, the dressing of the grinding wheel 14 by the dresser 46 is started. As a result, the dressing is automatically started at an appropriate timing when the spilling and the crushing of the grinding wheel 14 reach a predetermined state, so that the variation in the quality of the work material 44 is suppressed.

  Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other aspects.

  For example, in the above-described embodiment, the first signal strength SP1 of the first wavelength band B1 and the second signal strength SP2 of the second wavelength band B2 are used from the power spectrum generated from the AE signal SAE by the frequency analysis unit 50. ing. 25 to 40 kHz was used as the first wavelength band B1, and 45 to 65 kHz was used as the second wavelength band B2. However, since it is sufficient to use the wavelength band exclusively representing the eye spill and the wavelength band exclusively representing the blind spot in the power spectrum, the first wavelength band B1 may be a wavelength included in 25 to 40 kHz or a part of the wavelength band. The signal intensity of the wavelength band including the wavelength band including the wavelength band of 45 to 65 kHz may be used as the second wavelength band B2. For example, the first wavelength band B1 is a relatively narrow wavelength band including a part of the wavelength band of 25 to 40 kHz, for example, 32.5 kHz in the central portion, and the second wavelength band B2 is a wavelength band of 45 to 65 kHz. A relatively narrow wavelength band may be used, including a portion at the center, for example, 55 kHz. Even in this case, it is possible to quantitatively evaluate the state of the grinding surface such as the progress of the blind state and / or the progress of the spilled state of the grinding wheel 14.

  In the above-described embodiment, the AE sensor 22 is built in the grinding wheel 14. However, when the work material is ground by the grinding wheel 14 in a non-rotating state because it has a rectangular parallelepiped shape, for example, the work material It may be provided on a support base for supporting.

  Further, in the above-described embodiment, as the grinding wheel, the grinding wheel 14 in which the grindstone portion 16 made of the vitrified grindstone is fixed to the outer peripheral surface of the main body 18 is used, but if the AE sensor 22 is built-in. , May be entirely composed of a vitrified grindstone.

  Further, although the rotary dresser is used as the dresser 46 in FIG. 1 described above, a blade type dresser or the like may be used.

  The above description is merely an embodiment of the present invention, and the present invention can be modified in various ways without departing from the spirit of the present invention.

10: Grinding surface condition evaluation device 12: Grinding processing device 14: Grinding wheel (grinding wheel)
16: Grindstone part 22: AE sensor 34: A / D converter 40: Inorganic binder 44: Work material 46: Dresser 48: Surface state display device (ground surface state display device)
50: Frequency analysis unit 51: Grinding surface state output unit 74: Grinding automatic control unit 76: Dressing control unit SP1: First signal strength (evaluation value)
SP2: Second signal strength (evaluation value)
SP2R: Cumulative signal strength (evaluation value)
SR: Signal strength ratio (evaluation value)
SRT: Target signal strength ratio (target evaluation value)

Claims (9)

A grinding surface state evaluation device for evaluating a grinding surface state of a grinding wheel for grinding a work material,
An AE sensor that detects vibration generated in the grinding portion of the grinding wheel and outputs an AE signal;
An A / D converter that converts an AE signal output from the AE sensor into a digital signal;
A frequency analysis unit for frequency-analyzing the AE signal converted into a digital signal by the A / D converter to obtain a power spectrum;
Of the power spectrum obtained by the frequency analysis unit, generated by the first signal intensity in the first wavelength band related to the crushing of the abrasive grains of the grinding wheel and the contact between the abrasive grains of the grinding wheel and the work material. At least one of the second signal intensities of the second wavelength band related to the sliding vibration or the elastic vibration is calculated, and at least one of the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band is calculated. Based on the grinding surface state output unit that outputs an evaluation value related to the grinding surface state of the grinding wheel based on,
A grinding surface condition evaluation device comprising: At least one of the first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band is an integral value or a moving average value, and the grinding surface state output unit is The ground surface state evaluation according to claim 1, wherein the evaluation value related to the ground surface state of the grinding wheel is output based on the at least one of the one signal strength and the second signal strength of the second wavelength band. apparatus. The first signal intensity of the first wavelength band and the second signal intensity of the second wavelength band are integral values or moving average values, and the grinding surface state output unit is the first signal intensity of the first wavelength band. And a signal strength ratio of the second signal strength of the second wavelength band is calculated, and the evaluation value related to the grinding surface state of the grinding wheel is output based on the signal strength ratio. Grinding surface condition evaluation device. The grinding surface state evaluation device according to any one of claims 1 to 3, further comprising: a grinding surface condition display device that displays the evaluation value output from the grinding surface condition output unit. The first wavelength band is a wavelength band including a part of the wavelength band of 25 to 40 kHz, and the second wavelength band is a wavelength band including a part of the wavelength band of 45 to 65 kHz. The ground surface state evaluation device according to any one of claims 1 to 4. The first wavelength band is a wavelength band of 25 to 40 kHz, and the second wavelength band is a wavelength band of 45 to 65 kHz. The ground surface according to any one of claims 1 to 4, wherein Condition evaluation device. The grinding surface state evaluation device according to any one of claims 1 to 6, wherein a sampling cycle of the A / D converter is 10 µsec or less. A grinding apparatus for grinding the work material using the grinding wheel,
Cutting the grinding wheel into the work material so that the evaluation value output from the grinding surface state output unit according to any one of claims 1 to 7 becomes a preset target evaluation value. An automatic grinding control unit that adjusts at least one of a feed rate, a peripheral speed of the grinding wheel, a peripheral speed of the work material, and a feed speed of the work material. .. A grinding apparatus for grinding the work material using the grinding wheel and dressing the grinding wheel using a dresser,
When the evaluation value output from the grinding surface state output unit according to any one of claims 1 to 7 becomes a preset dressing start condition, grinding of the work material using the grinding wheel is performed. And a dressing control unit that starts dressing of the grinding wheel by the dresser.