WO2022049719A1

WO2022049719A1 - Cutting device

Info

Publication number: WO2022049719A1
Application number: PCT/JP2020/033554
Authority: WO
Inventors: 隆中村; 英二社本
Original assignee: 国立大学法人東海国立大学機構
Priority date: 2020-09-04
Filing date: 2020-09-04
Publication date: 2022-03-10

Abstract

This cutting device comprises a spindle 10 that is rotatably supported by a spindle housing 12 and to which is attached a cutting tool 20 or a workpiece 30. A rotation control unit 101 controls the rotation of the spindle 10. A feed mechanism 21 moves the cutting tool 20 relative to the workpiece 30. A contact structure 41 is in contact with the center of rotation of the spindle 10. A measurement unit 45 measures the voltage between the contact structure 41 and a contact point between the cutting tool 20 and the workpiece 30.

Description

Cutting equipment

This disclosure relates to a cutting device that cuts a work material.

Conventionally, the tool-work material thermocouple method is known as a method for measuring the tool cutting edge temperature. The tool-work material thermocouple method is a method of measuring the cutting temperature (tool cutting edge temperature) by using the thermoelectromotive force generated between the tool and the work material during cutting. This method utilizes the Zeebeck effect in which when a temperature difference occurs between the contacts of a loop made of two types of conductors, a thermoelectromotive force is generated between the contacts and a current flows through the loop. Since the thermoelectromotive force is determined by the temperature of the two contacts and the material of the two types of conductors, the cutting temperature can be obtained from the temperature calibration curve created in advance by measuring the thermoelectromotive force. The main component of the cutting tool material is generally non-metal, but in many cases, since it contains a conductive binder or the like, thermoelectromotive force measurement is possible.

Non-Patent Document 1 uses a mercury contact as an electric contact with a rotating spindle as a structure for realizing a tool-work material thermocouple method, and is an electrically insulating component for preventing a short circuit between the tool and the work material. Disclose the structure using. In Non-Patent Document 2, a slip ring is used for the electric contact with the rotating spindle as a structure for realizing the tool-work material thermocouple method, and electrical insulation is provided to prevent a short circuit between the tool and the work material. Disclose the structure using parts.

In cutting, the temperature of the tool edge rises due to shear deformation of the work material and friction on the rake face and flank surface. Since the tool cutting edge temperature affects the tool life and the surface properties of the machined surface, it is preferable to realize a practical structure capable of measuring the tool cutting edge temperature during cutting. Since the structure disclosed in Non-Patent Document 1 uses mercury contacts, there is a problem in terms of safety, and since the structure disclosed in Non-Patent Document 2 uses a slip ring, the spindle rotates several thousand revolutions / minute. If it rotates as described above, there is a problem that the conduction is not stable or the life is short due to wear.

This disclosure has been made in view of these circumstances, and the purpose thereof is to provide a technique for practically realizing the tool-work material thermocouple method. Another object of the present disclosure is to provide a technique for monitoring the voltage between the tool and the work material to determine the state of the tool.

In order to solve the above problems, the cutting apparatus of the present disclosure is rotatably supported by a spindle housing, and a spindle to which a tool or a work material is attached, a rotation control unit for controlling the rotation of the spindle, and a cover. A feed mechanism that moves the tool relative to the work material, a contact structure that contacts the center of rotation of the spindle, and a measuring unit that measures the voltage between the contact structure and the contact point between the tool and the work material. And prepare. The contact structure may be in contact with the spindle itself, but may be in contact with the center of rotation of the spindle by contacting a conductor component existing on the center of rotation of the spindle.

Another aspect of the cutting apparatus of the present disclosure is a spindle to which a cutting tool having one or more blades is attached, a feed mechanism for moving the cutting tool relative to the work material, and a contact point in contact with the spindle. A measuring unit that measures the voltage between the structure, the contact structure, and the contact point between the cutting tool and the work material, and a determination unit that determines the state of the cutting tool based on the voltage waveform measured by the measuring unit. And prepare.

It should be noted that any combination of the above components and the conversion of the expression of the present disclosure between methods, devices, systems, etc. are also effective as aspects of the present disclosure.

It is a figure which shows the schematic structure of the cutting apparatus of Embodiment 1. It is a figure which shows an example of a contact structure. It is a figure which shows another example of a contact structure. It is a figure which shows the schematic structure of the cutting apparatus of Embodiment 2. It is a figure which shows the correlation of the maximum flank wear width and a cutting temperature. It is a figure which shows the result of having experimented the relationship between the wear width of a tool flank and the cutting temperature. It is a figure which shows the example of the measured voltage waveform. It is a figure which shows the schematic structure of the cutting apparatus of Embodiment 3.

<Embodiment 1>
FIG. 1 shows a schematic configuration of the cutting apparatus 1a of the first embodiment. The cutting device 1a of the first embodiment is a lathe that rotates a work material 30 attached to a spindle 10 via a chuck 31 to cut a blade of a cutting tool 20 into the rotating work material 30. In the first embodiment, it is assumed that the cutting tool 20 and the work material 30 are different types of conductors, and the blade of the cutting tool 20 cuts the work material 30 at the cutting point 50.

The cutting device 1a includes a spindle housing 12 and a feed mechanism 21 for moving the cutting tool 20 relative to the work material 30 on the bed 2. The cutting tool 20 is fixed to the tool fixing portion 22, and the tool fixing portion 22 is movably supported by the feed mechanism 21. In the cutting device 1a of the first embodiment, the feed mechanism 21 moves the tool fixing portion 22 in the X-axis, Y-axis, and Z-axis directions to move the cutting tool 20 relative to the work material 30. The feed mechanism 21 may be configured to include a motor and a ball screw for each shaft.

The spindle 10 is rotatably supported by the spindle housing 12, and specifically,

metal bearings

13a and 13b fixed to the spindle housing 12 rotatably support the spindle 10. The rotation mechanism 11 includes a mechanism for rotating the spindle 10, and has a motor and a transmission structure for transmitting the rotational power of the motor to the spindle 10. The transmission structure may include a V-belt and gears that transmit the rotational power of the motor to the spindle 10. The rotation mechanism 11 is a built-in motor built in the spindle 10, and may directly drive the spindle 10.

The cutting device 1a of the first embodiment has a thermoelectromotive force monitoring unit 40 that monitors the thermoelectromotive force generated between the cutting tool 20 and the work material 30 during cutting by the tool-work material thermocouple method. Have. The cutting point 50 is a contact point where the cutting tool 20 which is a different kind of conductor and the work material 30 come into contact with each other. A thermostatic force is generated between the material 30 and the material 30. The thermoelectromotive force monitoring unit 40 includes a contact structure 41 electrically connected to the rotating spindle 10 and a lead wire 42 electrically connected to the contact structure 41 in order to realize a thermoelectromotive force measuring function. A measuring unit that measures the thermoelectromotive force (voltage) between the lead wire 43 electrically connected to the cutting tool 20, the electric resistance 44 provided between the lead wire 42 and the lead wire 43, and the contact structure 41 and the cutting point 50. It is equipped with 45.

The processing unit 100 includes a rotation control unit 101 that controls the rotation of the spindle 10 by the rotation mechanism 11, a movement control unit 102 that controls the relative movement between the cutting tool 20 and the work material 30 by the feed mechanism 21. A determination unit 103 for determining the state of the cutting tool 20 based on the voltage measured by the measurement unit 45 is provided.

The contact structure 41 contacts the rotation center of the spindle 10 and takes out an electric signal. Since the peripheral speed of the center of rotation is theoretically zero, the contact structure 41 comes into contact with the center of rotation of the spindle 10, and the wear of the contact portion can be suppressed. Since the work material 30 is attached to the tip end side (right side in FIG. 1) of the spindle 10 in FIG. 1 via the chuck 31, the contact structure 41 is on the rear end side (left side in FIG. 1) of the spindle 10. ), It is preferable to come into contact with the rotation center of the spindle 10. By arranging the contact structure 41 on the rear end side of the spindle 10 opposite to the tip end side on which the work material 30 is attached, the contact structure 41 is stable at the center of rotation of the spindle 10 regardless of the cutting conditions. Can contact and extract electrical signals.

FIG. 2 shows an example of the contact structure 41. The contact structure 41 has a first conductor component 41a fixed to the end of the spindle 10 and extending along the axis of the spindle 10, and a second conductor component 41b with which the first conductor component 41a comes into contact. The end of the conducting wire 42 is connected to the second conductor component 41b. The first conductor component 41a may be screwed to the rear end surface of the main shaft 10 and may be fixed by another coupling means. The first conductor component 41a and the second conductor component 41b may be formed of a copper-based, silver-based, gold-based, or graphite-based material (or an alloy containing them).

The first conductor component 41a abuts on the second conductor component 41b on the axis passing through the rotation center of the spindle 10. The first conductor component 41a may be a round bar member having a circular cross section. It is preferable that the first conductor component 41a has a small diameter portion whose diameter is reduced toward the second conductor component 41b, and the diameter of the region in contact with the second conductor component 41b is reduced. As a result, when the spindle 10 and the first conductor component 41a rotate, the wear in the contact region between the first conductor component 41a and the second conductor component 41b can be reduced. For example, the diameter of the contact region is preferably 0.5 mm or less. The first conductor component 41a may be a rod-shaped member having a polygonal cross section, and preferably has an inclined portion whose cross-sectional area is gradually reduced toward the second conductor component 41b.

Further, the first conductor component 41a may be a conical member or a pyramidal member instead of a rod-shaped member. Regardless of the shape of the first conductor component 41a, the area of the region that abuts and abuts on the second conductor component 41b on the axis passing through the rotation center of the spindle 10 is defined as the spindle 10. It is preferably smaller than the area to be connected.

FIG. 3 shows another example of the contact structure 41. The contact structure 41 has a first conductor component 41c that extends along the axis of the spindle 10 and contacts the center of rotation of the spindle 10. In the contact structure 41 shown in FIG. 3, the first conductor component 41c comes into contact with the second conductor component 41e attached to the end of the spindle 10 on an axis passing through the rotation center of the spindle 10. Contact the center of rotation of. The contact structure 41 may further include a third conductor component 41d that supports the first conductor component 41c. The first conductor component 41c, the second conductor component 41e, and the third conductor component 41d may be formed of a copper-based, silver-based, gold-based, or graphite-based material (or an alloy containing them).

The first conductor component 41c abuts on the second conductor component 41e on the axis passing through the rotation center of the spindle 10, and comes into contact with the rotation center of the spindle 10. The first conductor component 41c may be a round bar member having a circular cross section. It is preferable that the first conductor component 41c has a small diameter portion whose diameter is reduced toward the second conductor component 41e, and the diameter of the region in contact with the second conductor component 41e is reduced. As a result, when the spindle 10 is rotated, the wear of the contact region between the first conductor component 41c and the second conductor component 41e can be reduced. For example, the diameter of the contact region is preferably 0.5 mm or less. The first conductor component 41c may be a rod-shaped member having a polygonal cross section, and preferably has an inclined portion whose cross-sectional area is gradually reduced toward the second conductor component 41e.

Further, the first conductor component 41c may be a conical member or a pyramidal member instead of a rod-shaped member. Regardless of the shape of the first conductor component 41c, the area of the region that abuts and abuts on the second conductor component 41e on the axis passing through the rotation center of the spindle 10 is set to the area of the third conductor. It is preferably smaller than the area connected to the body component 41d.

In the cutting device 1a, since the electric signal on the work material 30 side is taken out from the contact structure 41 in contact with the rear end portion of the main shaft 10, it is necessary to electrically insulate the main shaft 10 and the main shaft housing 12. Here, the

bearings

13a and 13b are made of metal, and the spindle 10 in the stopped state is short-circuited with the spindle housing 12. For example, in Non-Patent Document 1, an insulating component is interposed between the spindle 10 and the spindle housing 12 to realize insulation between the spindle 10 and the spindle housing 12.

In this regard, the present disclosure discloses that when the

bearings

13a and 13b rotate at a rotation speed equal to or higher than a predetermined rotation speed RS, a fluid lubrication state is created, and the spindle 10 and the spindle housing 12 are electrically conducted by the lubricating oil. It was found as a finding that the phenomenon of disappearance occurs. Utilizing this phenomenon, in the cutting device 1a, when the rotation control unit 101 is rotating the spindle 10 at a rotation speed equal to or higher than a predetermined rotation speed RS, the movement control unit 102 controls the feed mechanism 21 to be covered. The cutting tool 20 is cut into the cutting material 30, and the determination unit 103 determines the state of the cutting tool 20 using the voltage measured by the measuring unit 45. The predetermined rotation speed RS depends on the bearing, but is about several hundred rotations / minute. Therefore, in the cutting device 1a, the measuring unit 45 can measure the thermoelectromotive force without adding an insulating component between the spindle 10 and the spindle housing 12.

When the measuring unit 45 measures the voltage, the spindle 10 and the rotating mechanism 11 also need to be electrically insulated. For example, when the rotating mechanism 11 uses a V-belt as a power transmission structure, the spindle 10 and the rotating mechanism 11 may be electrically insulated by forming the V-belt with an insulating material such as rubber. Further, when the rotating mechanism 11 uses gears as a power transmission structure, a fluid lubrication state is created between the rotating gears as described above, and lubricating oil is interposed between the meshing teeth. Therefore, the main shaft 10 and the rotation mechanism 11 are electrically insulated. Therefore, in the cutting device 1a, the measuring unit 45 can measure the thermoelectromotive force without adding an insulating component between the spindle 10 and the rotating mechanism 11.

In the cutting device 1a, the conducting wire 43 is connected to the tool fixing portion 22 for fixing the cutting tool 20, and an electric signal is taken out. For example, it is possible to connect the conductor 43 to the bed 2, but since the feed mechanism 21 is supported by the bearing, the bearing is fluid-lubricated when the feed mechanism 21 moves at high speed, as in the spindle 10 described above. A situation may occur in which the tool fixing portion 22 and the bed 2 become non-conducting. Therefore, by connecting the lead wire 43 to the tool fixing portion 22, it is possible to stably take out the electric signal on the cutting tool 20 side.

<Embodiment 2>
FIG. 4 shows a schematic configuration of the cutting device 1b of the second embodiment. In the cutting device 1b of the second embodiment, the configuration represented by the same reference numeral as the cutting device 1a of the first embodiment has the same or the same structure and function as the configuration of the cutting device 1a.

The cutting device 1b of the second embodiment is a horizontal milling machine or a horizontal machining center that rotates a cutting tool 20 attached to a spindle 10 via a holder 32 and cuts a blade of the rotating cutting tool 20 into a work material 30. be. In the second embodiment, it is assumed that the cutting tool 20 and the work material 30 are different types of conductors, and the blade of the cutting tool 20 cuts the work material 30 at the cutting point 50.

The cutting device 1b is provided with

feed mechanisms

24 and 25 on the bed 2 for moving the cutting tool 20 relative to the work material 30. The work material 30 is fixed to the work material fixing portion 23, and the work material fixing portion 23 is movably supported by the feed mechanism 24. The spindle housing 12 is movably supported by the feed mechanism 25. In the cutting device 1b of the second embodiment, the feed mechanism 24 moves the work material fixing portion 23 in the X-axis direction, and the feed mechanism 25 moves the spindle housing 12 in the Y-axis direction and the Z-axis direction. 24 and 25 move the cutting tool 20 relative to the work material 30. The

feed mechanism

24, 25 may be configured to include a motor and a ball screw for each shaft.

metal bearings

13a and 13b fixed to the spindle housing 12 rotatably support the spindle 10. The rotation mechanism 11 includes a mechanism for rotating the spindle 10, and has a motor and a transmission structure for transmitting the rotational power of the motor to the spindle 10. The rotation mechanism 11 is a built-in motor built in the spindle 10, and may directly drive the spindle 10.

The cutting device 1b of the second embodiment has a thermoelectromotive force monitoring unit 40 that monitors the thermoelectromotive force generated between the cutting tool 20 and the work material 30 during cutting. The thermoelectromotive force monitoring unit 40 includes a contact structure 41 that is electrically connected to the rotating spindle 10, a conductor 42 that is electrically connected to the contact structure 41, and a conductor 43 that is electrically connected to the work material 30. And an electric resistance 44 provided between the conductor 42 and the conductor 43, and a measuring unit 45 for measuring the thermoelectromotive force (voltage) between the contact structure 41 and the cutting point 50. The contact structure 41 contacts the center of rotation of the spindle 10 and takes out an electric signal. Since the peripheral speed of the center of rotation is theoretically zero, the contact structure 41 comes into contact with the center of rotation of the spindle 10, and the wear of the contact portion can be suppressed.

In the cutting device 1b, the conducting wire 43 is connected to the work material fixing portion 23 for fixing the work material 30, and an electric signal is taken out. For example, it is possible to connect the conductor 43 to the bed 2, but since the feed mechanism 21 is supported by the bearing, the bearing is fluid-lubricated when the feed mechanism 21 moves at high speed, as in the spindle 10 described above. A situation may occur in which the work material fixing portion 23 and the bed 2 become non-conducting. Therefore, by connecting the conductor 43 to the work material fixing portion 23, it is possible to stably take out the electric signal on the work material 30 side.

The processing unit 100 includes a rotation control unit 101 that controls the rotation of the spindle 10 by the rotation mechanism 11, a movement control unit 102 that controls the relative movement between the cutting tool 20 and the work material 30 by the feed mechanism 21. A determination unit 103 for determining the state of the cutting tool 20 based on the voltage measured by the measurement unit 45 is provided. The determination unit 103 may obtain the cutting temperature from the voltage measured by the measuring unit 45 using a temperature calibration curve or a temperature calibration table for calibrating the thermoelectromotive force to the cutting temperature (temperature at the cutting point 50). can.

It is known that the cutting temperature increases with the progress of tool wear.
FIG. 5 shows the correlation between the maximum flank wear width and the cutting temperature. The determination unit 103 may determine the wear state of the cutting tool 20 by obtaining the cutting temperature from the voltage measured by the measuring unit 45 during the cutting process. For example, the determination unit 103 may determine that the tool has reached the end of its life when the cutting temperature exceeds a predetermined threshold value.

Conventionally, since the tool life is time-controlled, there are situations where the tool cannot be used until the true tool life, or conversely, the tool that exceeds the life continues to be used. Therefore, the determination unit 103 of the embodiment accurately determines the tool life by obtaining the cutting temperature from the voltage measured by the measurement unit 45 and acquiring the wear width of the tool with reference to the correlation shown in FIG. You can do it. If there is a curve or table showing the correlation between the maximum flank wear width and the thermoelectromotive force, the determination unit 103 can use the cutting tool from the voltage measured by the measuring unit 45 without obtaining the cutting temperature. The wear state of 20 may be determined.

FIG. 6 shows the experimental results of measuring the wear width and the cutting temperature of the tool flank surface using the contact structure 41 in the embodiment. As an experimental environment, a vertical milling machine was used, an end mill was used as a tool, and a steel material (SS400) was used as a work material. Further, as the contact structure 41, the structure shown in FIG. 2 was used.

FIG. 6A shows the state of the tool flank surface before cutting. The tool is in new condition and the cutting edge is not worn.
FIG. 6B shows the state of the tool relief surface when the cutting temperature is measured as 660 degrees. The maximum flank wear width at this time was 126 μm, and the cutting temperature and wear width consistent with the correlation shown in FIG. 5 were obtained.
FIG. 6 (c) shows the state of the tool relief surface when the cutting temperature is measured as 720 degrees. The maximum flank wear width at this time was 226 μm, and the cutting temperature and wear width consistent with the correlation shown in FIG. 5 were obtained.
From the above experiment, it was confirmed that the electric signal can be stably taken out from the spindle 10 by adopting the contact structure 41 of the embodiment.

FIG. 7 shows an example of a voltage waveform measured by the measuring unit 45. This voltage waveform was measured during machining using a two-flute end mill. When the blade starts cutting, the cutting temperature rises instantly, and when cutting is finished, the cutting temperature drops instantly. The situation is shown.

In the case of a tool having a plurality of blades such as an end mill, as shown in FIG. 7, the measuring unit 45 measures the thermoelectromotive force generated by cutting each blade. The two pulse waveforms shown in FIG. 7 show the thermoelectromotive force generated by cutting with two different blades of the end mill. The two pulse waveforms are similar, indicating that the two blades of the end mill are cutting with substantially the same wear conditions and with substantially the same cutting thickness. If the tool is eccentric and the cutting thickness of each blade is different, the magnitude of the pulse waveform of each blade will be different. Utilizing this fact, the determination unit 103 may determine whether or not the tool having the plurality of blades is eccentric based on the magnitude of the pulse waveform measured by the measurement unit 45.

Further, the determination unit 103 may determine uneven wear of blades having different wear amounts among the plurality of blades from the voltage waveform measured by the measurement unit 45. Specifically, the determination unit 103 compares the pulse waveforms of each blade, and determines the uneven wear of one of the blades when the pulse waveforms are different, that is, when the pulse waveforms are not similar. Further, the determination unit 103 may determine the blade defect from the change in the voltage waveform measured by the measurement unit 45. Specifically, the determination unit 103 repeats the comparison of the pulse waveforms by each blade for each rotation, and when the difference in the magnitude of the pulse waveforms suddenly increases, the determination unit 103 determines the defect of the blade whose magnitude has decreased. As described above, the determination unit 103 may determine the state of the cutting tool 20 based on the voltage waveform when cutting with each of the plurality of blades.

<Embodiment 3>
FIG. 8 shows a schematic configuration of the cutting apparatus 1c of the third embodiment. The cutting device 1c brings the cutting tool 20 and the work material 30 into contact with each other before the start of full-scale cutting, for the purpose of specifying the relative positional relationship between the cutting tool 20 and the work material 30. It has a function to acquire the position information of the time. In the cutting device 1c of the third embodiment, the configuration represented by the same reference numeral as the cutting device 1a of the first embodiment has the same or the same structure and function as the configuration of the cutting device 1a. The cutting device 1c of the third embodiment may have the same configuration as the cutting device 1a except that the conducting wire 42 or the conducting wire 43 is provided with a voltage applying portion 46 for applying a predetermined voltage.

The voltage application unit 46 applies a predetermined voltage between the cutting tool 20 and the work material 30. When the rotation control unit 101 is rotating the spindle 10 at a rotation speed equal to or higher than a predetermined rotation speed RS, the determination unit 103 includes the cutting tool 20 and the work material 30 based on the voltage measured by the measurement unit 45. Determines that they have touched. Specifically, the determination unit 103 detects that a current has flowed based on the voltage measured by the measurement unit 45. The determination unit 103 may detect the contact between the cutting tool 20 and the work material 30 by monitoring the pulse waveform of the thermoelectromotive force shown in FIG. 7, but the thermoelectromotive force is several mV to several tens of mV. It is weak. Therefore, by applying a bias voltage sufficiently higher than the thermoelectromotive force by the voltage application unit 46, the determination unit 103 can accurately detect the contact between the cutting tool 20 and the work material 30.

In the third embodiment, since the purpose is to detect contact, a tool (dummy tool) that does not cut the work material 30 may be used instead of the cutting tool 20. In this case, the relative positional relationship between the work material 30 and the tool fixing portion 22 can be specified by using the known tool (dummy tool) dimensions. Since the thermoelectromotive force does not have to be used in the third embodiment, the dummy tool and the work material 30 may be formed of the same type of conductor.

The present disclosure has been described above based on the embodiment. It will be appreciated by those skilled in the art that this embodiment is exemplary and that various modifications are possible for each of these components and combinations of processing processes, and that such variants are also within the scope of the present disclosure. ..

The outline of the aspects of the present disclosure is as follows.
A cutting device of one aspect of the present disclosure is a spindle that is rotatably supported by a spindle housing and to which a tool or work material is attached, a rotation control unit that controls rotation of the spindle, and a tool relative to the work material. It is provided with a feed mechanism for moving the spindle, a contact structure in contact with the center of rotation of the spindle, and a measuring unit for measuring the voltage between the contact structure and the contact point between the tool and the work material.

According to this aspect, it is possible to suppress the wear of the contact structure by using the contact structure that contacts the center of rotation of the spindle.

The contact structure may include a first conductor component that is fixed to the end of the spindle and extends along the axis of the spindle, and a second conductor component that contacts the center of rotation of the first conductor component. .. When the second conductor component comes into contact with the rotation center of the rotating first conductor component, it is possible to suppress wear at the contact portion. The first conductor component and the second conductor component may be made of a copper-based, silver-based, gold-based or graphite-based material.

The contact structure has a first conductor component extending along the axis of the spindle and a second conductor component attached to the center of rotation at the end of the spindle, and the first conductor component is the second conductor component. May be in contact with. When the first conductor component comes into contact with the rotation center of the second conductor component attached to the spindle, it is possible to suppress wear at the contact portion. The first conductor component and the second conductor component may be made of a copper-based, silver-based, gold-based or graphite-based material.

A tool or work material may be attached to one end side of the spindle, and the contact structure may come into contact with the center of rotation of the spindle on the other end side of the spindle. With this configuration, the end of the spindle on the side not used in cutting can be effectively used. As shown in Non-Patent Document 2, the existing slip ring has an electric contact on a cylindrical surface away from the center of rotation and is not suitable for long-term use in a high rotation speed range, but this is an electric circuit. This is because it always has two or more contacts in order to have a closed configuration. In that sense, the present disclosure is a peculiar use, and since it already has an electric contact called a cutting point, the electric contact can be arranged at one rotation center.

The cutting device may further include a determination unit for determining the state of the tool based on the voltage measured by the measurement unit. The determination unit may determine the state of the tool based on the voltage waveform measured by the measurement unit when the rotation control unit is rotating the spindle at a rotation speed equal to or higher than a predetermined rotation speed. When the spindle rotates at a predetermined rotation speed or higher, the bearings supporting the spindle do not come into solid contact due to the dynamic pressure of the lubricating oil, and the spindle and the spindle housing are substantially electrically insulated from each other. Therefore, the determination unit may determine the state of the tool based on the voltage waveform measured by the measurement unit when the main shaft and the main shaft housing are substantially insulated.

The cutting device is based on a voltage application unit that applies a voltage between the tool and the work material, and a voltage measured by the measurement unit when the rotation control unit is rotating the spindle at a rotation speed higher than a predetermined rotation speed. Further, a determination unit for determining that the tool and the work material have come into contact with each other may be provided. The determination unit may determine the contact between the tool and the work material based on the voltage measured by the measurement unit when the main shaft and the main shaft housing are substantially insulated. When the determination unit detects that a current has flowed based on the voltage measured by the measurement unit, it may determine that the tool and the work material have come into contact with each other.

Another aspect of the present invention is also a cutting device. This device includes a spindle to which a cutting tool with one or multiple blades is attached, a feed mechanism that moves the cutting tool relative to the work material, a contact structure that contacts the spindle, and the contact structure. It is provided with a measuring unit for measuring the voltage between the cutting tool and the contact point of the work material, and a determining unit for determining the state of the cutting tool based on the voltage waveform measured by the measuring unit.

According to this aspect, it is possible to determine the state of the cutting tool from the measured thermoelectromotive force waveform. The determination unit may determine the state of the blade in the cutting tool based on the voltage waveform when cutting with each of the plurality of blades.

This disclosure can be used for a cutting device that cuts a work material.

1a, 1b, 1c ... cutting device, 10 ... spindle, 12 ... spindle housing, 13a, 13b ... bearing, 20 ... cutting tool, 21 ... feed mechanism, 22 ... Tool fixing part, 23 ... Work material fixing part, 24, 25 ... Feed mechanism, 30 ... Work material, 40 ... Thermoelectric power monitoring unit, 41 ... Contact structure, 41a ... First conductor parts, 41b ... second conductor parts, 41c ... first conductor parts, 41d ... third conductor parts, 41e, second conductor parts, 42,43. ... Conductor wire, 44 ... Electric resistance, 45 ... Measurement unit, 46 ... Voltage application unit, 50 ... Cutting point, 100 ... Processing unit, 101 ... Rotation control unit, 102.・・ Movement control unit, 103 ・・・ Judgment unit.

Claims

With a spindle that is rotatably supported by the spindle housing and to which a tool or work material is attached,
A rotation control unit that controls the rotation of the spindle,
A feed mechanism that moves the tool relative to the work material,
The contact structure that contacts the center of rotation of the spindle and
A measuring unit that measures the voltage between the contact structure and the contact point between the tool and the work material.
A cutting device equipped with.
The contact structure has a first conductor component that is fixed to the end of the spindle and extends along the axis of the spindle, and a second conductor component that contacts the rotation center of the first conductor component. ,
The cutting apparatus according to claim 1.
The contact structure has a first conductor component extending along the axis of the spindle and a second conductor component attached to the center of rotation of the end of the spindle, and the first conductor component is the first conductor component. Contacting the second conductor component,
The cutting apparatus according to claim 1.
The first conductor component and the second conductor component are formed of a copper-based, silver-based, gold-based or graphite-based material.
The cutting apparatus according to claim 2 or 3.
A tool or work material is attached to one end side of the spindle.
On the other end side of the spindle, the contact structure contacts the center of rotation of the spindle.
The cutting apparatus according to any one of claims 1 to 4.
Further, a determination unit for determining the state of the tool based on the voltage measured by the measurement unit is provided.
The determination unit determines the state of the tool based on the voltage measured by the measurement unit when the rotation control unit is rotating the spindle at a rotation speed equal to or higher than a predetermined rotation speed.
The cutting apparatus according to any one of claims 1 to 5.
A voltage application part that applies voltage between the tool and the work material,
A determination unit that determines that the tool and the work material have come into contact with each other based on the voltage measured by the measurement unit when the rotation control unit is rotating the spindle at a rotation speed equal to or higher than a predetermined rotation speed. ,
The cutting apparatus according to any one of claims 1 to 5, further comprising.
When the determination unit detects that a current has flowed based on the voltage measured by the measurement unit, it determines that the tool and the work material have come into contact with each other.
The cutting apparatus according to claim 7.
A spindle to which a cutting tool with one or more blades can be attached,
A feed mechanism that moves the cutting tool relative to the work material,
The contact structure that contacts the spindle and
A measuring unit for measuring a voltage between the contact structure and a contact point between the cutting tool and the work material, and a measuring unit.
A determination unit that determines the state of the cutting tool based on the voltage waveform measured by the measurement unit, and a determination unit.
A cutting device equipped with.
The determination unit determines the state of the blades in the cutting tool based on the voltage waveform when cutting with each of the plurality of blades.
The cutting apparatus according to claim 9.