JP7132349B2 - Tool shape measuring device and tool shape measuring method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tool shape measuring apparatus and a tool shape measuring method for measuring tool shapes such as tool length, tool diameter, and shape of the cutting edge of the tool.

Conventionally, there has been provided a shape measuring device for a rotary tool used in a machine tool. The tool profile measuring device is used, for example, for profile measurement of an end mill of a milling machine.

JP 2007-49489 A

Patent Literature 1 can measure the shape of a tool, but does not describe a rotating tool. A rotating tool changes its machining point due to thermal displacement or the like. We want to accurately measure the position of the machining point during rotation in order to compensate for thermal displacement. In addition, if it is possible to measure the shape of a tool even while it is rotating at the number of revolutions used for machining, it will be possible to observe chipping and wear and use it for tool replacement and tool wear compensation. In Patent Document 1, it is necessary to stop the tool for measurement, which takes time. Moreover, if the tool is stopped, the measurement results will be different from the shape of the tool being machined, making it impossible to accurately correct the position of the machining point.

SUMMARY OF THE INVENTION The present invention has been made in consideration of such circumstances, and provides a tool shape measuring apparatus and a tool shape measuring method that are capable of measuring the shape of a tool even while it is rotating.

In order to achieve the above object, the present invention has the following features. In the present invention, it is possible to read the rotation angle of the spindle on which the tool is attached and rotated from the angle sensor, and to photograph the shape of the tool at the specified angle.

Further, a tool shape measuring device according to an aspect of the present invention is a tool shape measuring device for measuring a shape of a tool installed on a spindle of a machine tool, comprising a camera for photographing the tool and a rotation angle of the spindle. and a control device for outputting a photographing command to the camera according to the rotation angle of the main shaft detected by the main shaft rotation angle sensor.

Further, in the tool shape measuring device according to the aspect of the present invention, the spindle rotation angle sensor is configured to also detect the number of rotations of the spindle, and the control device outputs a photographing command to the camera. is changed according to the rotation speed of the main shaft.

Further, the tool shape measuring apparatus according to the aspect of the present invention includes a light emitting device, and is configured such that the light emitting device emits light toward the tool in response to an output of a photographing command to the camera by the control device. there is

Further, the tool shape measuring apparatus according to the aspect of the present invention is configured such that the light emitting device emits light within a time period during which the shutter of the camera is open, in response to the control device outputting a photographing command to the camera. ing.

Moreover, in the tool shape measuring device according to the aspect of the present invention, the camera is installed on one side of the tool, and the light emitting device is installed on the other side . The light emitting device emits light toward the tool, so that the tool is photographed by the camera, and the light emitting device emits parallel light toward the tool.

Further, in the tool shape measuring apparatus according to the aspect of the present invention, the spindle rotation angle sensor outputs a continuous pulse signal while the spindle is rotating, and outputs a pulse signal of one cycle each time the spindle rotates. configured to emit a signal.

Further, in the tool shape measuring apparatus according to the aspect of the present invention, there is a first output as an output of the photographing command by the control device, and the first output causes the plurality of workpieces in a state in which the spindle is rotated by a predetermined angle. is configured to obtain an image of

Further, the tool shape measuring apparatus according to the aspect of the present invention further includes a tool rotation angle input unit for inputting a rotation angle of the tool, which further includes a second output as an output of the photographing command by the control device. After the first output, the device is configured to output the second output in order to photograph the tool at the rotation angle input by the tool rotation angle input section.

A tool shape measuring method according to an aspect of the present invention is a tool shape measuring method for measuring a shape of a tool installed on a spindle of a machine tool, comprising: a spindle rotation angle detecting step of detecting a rotation angle of the spindle; and a photographing step of photographing the tool according to the rotation angle of the spindle detected in the spindle rotation angle detection step.

Further, in the tool shape measuring method according to the aspect of the present invention, the spindle rotation angle detecting step is a step of also detecting the number of rotations of the spindle, and in the photographing step, the photographing timing is determined by the number of rotations of the spindle. is changed according to

Moreover, in the tool shape measuring method according to the aspect of the present invention, in the photographing step, the light emitting device emits light toward the tool when the photographing is performed.

Moreover, in the tool shape measuring method according to the aspect of the present invention, in the photographing step, the light emitting device emits light within a time period during which the shutter of the camera is open.

Further, in the tool shape measuring method according to the aspect of the present invention, a camera for taking pictures in the photographing step is installed on one side with the tool in between, and the light emitting device is installed on the other side. The light emitting device emits light toward the tool, so that the tool is photographed by the camera in the photographing step, and the light emitting device emits parallel light toward the tool. ing.

Further, in the tool shape measuring method according to the aspect of the present invention, the spindle rotation angle detection step includes outputting a continuous pulse signal while the spindle is rotating, pulse signal is output.

Further, in the tool shape measuring method according to the aspect of the present invention, the photographing step includes a first step, and the first step is to photograph a plurality of images in a state in which the spindle is rotated by a predetermined angle. It is a process.

Further, in the tool shape measuring method according to the aspect of the present invention, there is further a second step as the photographing step. It is a step of photographing only the image of the tool that is in the state.

According to the present invention, the shape of a rotating tool can be measured, and the shape of the tool including thermal displacement and the like during machining can be measured more accurately. By correcting the machining point of the tool using the measured tool shape, machining with higher precision becomes possible.

FIG. 1 is a schematic diagram showing an apparatus configuration (apparatus according to the first embodiment) of an example of the present invention. FIG. 2 is a view of the tool shape being measured by the example of the present invention (apparatus according to the first embodiment). FIG. 3 is a cross-sectional view of a two-bladed tool as an example of the tool measured by the tool shape measuring device according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view of a three-bladed tool as another example of the tool measured by the tool shape measuring device according to the first embodiment of the present invention. FIG. 5(a) is a diagram showing a schematic configuration of a spindle head of a machine tool used in the second embodiment of the present invention, and FIG. FIG. 5(c) is a diagram showing a continuous pulse signal obtained by a spindle rotation angle sensor. FIG. 6 is a diagram showing a tool (rotating tool) to be measured by the tool shape measuring device according to the second embodiment of the present invention. It is the figure seen in the drawing direction. FIG. 7 is a diagram for explaining the positional relationship among a light emitting device, a tool, and a camera in a tool shape measuring apparatus according to a second embodiment of the present invention. It is the figure seen in the drawing direction. FIG. 8(a) is an image of the tool obtained by the tool shape measuring device according to the comparative example, and FIG. 8(b) is an image obtained by the tool shape measuring device according to the second embodiment of the present invention. It is an image of a tool. FIG. 9(a) is a diagram showing a ball end mill as an example of a tool, FIG. 9(b) is a diagram showing a square end mill as an example of a tool, and FIG. 9(c) is an example of a tool. FIG. 9D is a diagram showing a radius end mill, and FIG. 9D is a diagram showing a shape error in a ball end mill. 10(a) and 10(b) are diagrams for explaining the imaging time lag in the tool shape measuring device according to the second embodiment of the present invention. FIG. 11(a) is a diagram showing a cylindrical dummy tool used in a tool shape measuring apparatus according to a second embodiment of the present invention, and FIG. 11(b) is a side view of the cylindrical dummy tool. It is a development view of.

[First embodiment]
A first embodiment according to the present invention is shown below. A machine tool 2 shown in FIG. 1 has a table 16 on the upper surface of a bed 18 and a gate-shaped column 10 , and a spindle head 4 is supported by a cross rail 8 of the column 10 via a saddle 6 . A spindle 11 is supported on the spindle head 4 .

Here, for convenience of explanation, one horizontal direction is defined as the X direction (X-axis direction), another horizontal direction perpendicular to the X direction is defined as the Y direction (Y-axis direction), A vertical direction orthogonal to the X direction and the Y direction is defined as a Z direction (Z-axis direction).

The table 16 is movable in the X-axis direction with respect to the bed 18 . The saddle 6 is movable along the cross rail 8 in the Y-axis direction. The spindle head 4 is movable with respect to the saddle 6 in the Z-axis direction. By moving these three axes, it is possible to three-dimensionally move the tool 12 with respect to the workpiece 14 placed on the table 16 and perform machining. A tool shape measuring device 1 is installed at the end of the table 16 . The control device 20 is connected to the machine tool 2 and the tool shape measuring device 1 and can control the machine tool 2 and the tool shape measuring device 1 .

FIG. 2 shows a diagram of measuring the shape of the tool 12 with the tool shape measuring device 1. As shown in FIG. The tool 12 is moved to the position shown in FIG. 2 by the three axes shown above, and the shape of the tool is measured. The tool shape measuring apparatus 1 includes a camera 22 and an illumination device 24, and the tool shape is measured while the tool 12 is positioned between the camera 22 and the illumination device 24 as shown in FIG. Since the image is captured by illuminating the tool 12 from behind with the light from the illumination device 24, the shape of the tool 12 is captured as a shadow.

The camera 22 has a high-speed shutter, and can take still images even while the tool 12 is rotating at several thousand revolutions per minute. A zoom lens may be attached to the camera 22 so that the control device 20 can control the enlargement ratio. The main shaft 11 is provided with a rotation angle sensor (not shown), and the control device 20 can control the rotation speed, positioning of the rotation angle, and the like.

When the tool 12 rotates at a rotation speed of 10,000 rpm or more, it is difficult to cope with only a high-speed shutter. In this case, the illumination device 24 is assumed to have a strobe function. If a strobe with a short light emission time of several microseconds is used, it is possible to measure the shape of the rotating tool 12 as well. Note that the maximum rotation speed of the tool 12 can be set to about 120,000 rpm.

FIG. 3 shows an example of the tool 12A used, which is a two-blade end mill. A cross section viewed from the work 14 side in a state of being attached to the machine tool 2 is shown. FIG. 4 shows an example of the tool 12B to be used, which is a three-flute end mill. A cross section viewed from the work 14 side in a state of being attached to the machine tool 2 is shown.

Next, a method for measuring the shape of a tool will be described using the tool 12A shown in FIG. A tool 12A is attached to the spindle 11. - 特許庁Before machining the workpiece 14, the tool 12A is moved to the measurement position shown in FIG. 2 to measure the shape of the tool. First, determine the tool reference angle. The tool reference angle indicates the angle at which the camera 22 can photograph the tool 12A from the direction indicated by the arrow 26A in FIG. The angle indicated by the arrow 26A is the maximum distance from the position of the spindle rotation axis to the outer shape of the tool 12A in the direction orthogonal to the spindle rotation axis. The distance is measured, for example, by counting the number of pixels in the digital image.

This tool reference angle is determined as follows. In FIG. 3, the position of the arrow 26A indicates the direction of the camera 22 for photographing, and the main shaft 11 is manually rotated so that the angle of the tool 12A that can be photographed from this position is close to that of the tool 12A. The image captured by the camera 22 can be checked on a monitor (not shown). When the angle of the arrow 26A is reached, the tool 22A is rotated by a predetermined angle in the forward and reverse directions, and a plurality of images are taken by the camera 22 at each predetermined angle. The angle of the spindle 11 at the position where the distance from the rotation axis of the spindle 11 to the outer shape of the tool 12A is the longest from the image is taken as the tool reference angle.

Alternatively, the tool reference angle can be determined as follows. Since the tool 12A has two blades, the tool 12A is rotated at a low speed of 180° or more from an arbitrary position, and an image is taken at each predetermined angle. The angle of the spindle 11 at the position where the distance from the rotation axis of the spindle 11 to the outer shape of the tool 12A is the longest in the captured image is taken as the tool reference angle.

Since the tool 12B shown in FIG. 4 has three blades, it is only necessary to rotate the main shaft 11 by 120° or more for photographing. In this case, the position of the arrow 26B shown in FIG. 4 indicates the orientation of the camera 22 for photographing, as in the case described with reference to FIG. For a tool that is not rotationally symmetrical, the number of photographed images increases. Select the desired image from

Information indicating that the tool 12 to be used has two blades or three blades may be input to the control device 20 by an input device (not shown), or may be stored as a database in a storage device within the control device 20. good.

Before machining the workpiece 14, the tool length, tool diameter, tool shape such as the shape of the cutting edge of the tool 12 (12A, 12B) are measured. These values are compared later when the amount of thermal displacement and the amount of tool wear are determined.

Next, the tool length measurement during machining will be described. When the designated time set in the control device 20 comes while the work 14 is being machined by the machine tool 2, the machine tool 2 stops machining and moves the tool 12 to the tool length measuring position shown in FIG. At this time, without stopping the rotation of the spindle 11, the tool 12 is moved and measured by the tool shape measuring device 1 while maintaining the rotational speed during machining. Therefore, it is possible to accurately measure the shape of the tool while it is still affected by centrifugal force during rotation. It can be processed with high accuracy.

When measuring the shape of the two blades of the tool 12A, when the spindle 11 reaches the previously obtained tool reference angle, the control device 20 outputs a measurement command to the tool shape measuring device 1, and the tool shape image is captured. . In the case of the tool 12A having two blades, the shapes of all the blades can be photographed by photographing at positions of the tool reference angle and the tool reference angle +180°. Since the tool 12B has three blades, the shapes of all the blades can be photographed by photographing at positions of the tool reference angle, the tool reference angle +120°, and the tool reference angle +240°.

Photographing may be performed for one rotation of the blade, or may be performed for multiple rotations. Even in the case of a tool with multiple blades, all blades can be managed by photographing the shapes of the blades one by one.

If the control device 20 issues a photographing command after the tool reference angle and the angle of the spindle 11 match, the actual photographing timing may be delayed if the spindle 11 rotates at high speed. In order to prevent this, the control device may output a photographing command slightly before the tool reference angle and the angle sensor of the spindle 11 match. The angle at which the command should be output is measured in advance by experiment. Experiments may be conducted at a plurality of rotation speeds, the angles obtained and tabulated, and appropriate angles obtained from this table according to the rotation speed.

When the tool 12 is rotated at a rotation speed of 10,000 rpm or more, a lighting device 24 with a flash function (stroboscopic function) is used, and the value of the spindle 11 rotation sensor and the value of the photographing angle of the tool 12 are as follows. correspond to The tool 12 is rotated, and at a certain rotation sensor value, the control device 20 outputs a photographing command to the tool shape measuring device 1 to photograph an image.

Next, an image of the tool 12 rotated by a predetermined angle from the previous image is photographed. The predetermined angle is 5°, for example. In this case, the shutter speed of the camera 22 cannot catch up, and it is impossible to take an image shifted by 5° during one rotation of the tool 12 . For this reason, an image is taken at an angle rotated by, for example, 10 rotations and 5° from the previous image.

The illumination device 24 can set the time for delaying the timing of light emission with respect to the command in μsec units. Therefore, it is possible to accurately photograph an image that is shifted by 10 rotations and 5 degrees. Such images are taken for a predetermined rotation angle of the tool 12, and the values of the spindle 11 rotation sensor and the values of the imaging angle of the tool 12 are associated from those images.

When the value of the spindle 11 rotation sensor and the value of the photographing angle of the tool 12 are associated with each other, the delay time when the illumination device 24 emits light is appropriately set, and the photographing command is issued from the control device 20 at an appropriate timing to measure the shape of the tool. By outputting to the device 1, an image of the desired degree of angular rotation of the tool 12 can be photographed. When measuring the blade shape of a two-bladed tool such as the tool 12A, first photograph the first blade, and then measure the shape of the second blade after rotating 10 and 180 degrees, for example. .

If the value measured before machining the work and the value measured during machining deviate by a predetermined value, a correction value is determined from that value and set in the control device 20 as the correction value. Also, if the distance from the axis of rotation of the spindle 11 to the outer shape of the tool 12 remarkably fluctuates depending on the blade and the tool 12 rotates, it is determined that the rotational runout of the tool 12 is large, and an alarm is displayed on the monitor of the controller 20. good too. Also, if there is no significant variation depending on the blade, but if only one blade has a shorter distance, it may be determined that the blade is chipped and an alarm may be generated.

As described above, when the tool shape is measured using the tool shape measuring apparatus 1 of the present invention, the measurement can be performed by rotating the spindle 11 at the number of revolutions during machining. can be measured. In addition, since the image can be captured in synchronization with the value of the rotation angle sensor of the spindle 11, only the image of the required rotation angle state of the tool 12 can be captured, and the capacity of the recording device can be reduced.

[Second embodiment]
A machine tool 2 (see FIG. 1) used in the second embodiment of the present invention is the same as the machine tool 2 used in the first embodiment of the present invention. etc. The control device 20 includes a CPU and a memory (not shown).

The tool shape measuring device 1a according to the second embodiment of the present invention is also configured substantially in the same manner as the tool shape measuring device 1 according to the first embodiment of the present invention, and operates and is used in substantially the same manner. is.

A tool 12 to be measured by the tool shape measuring apparatuses 1 and 1a according to the embodiments of the present invention is used, for example, when forming the surface of a mold core or cavity by cutting. The cutting work is performed, for example, for final finishing of the surfaces of the core and cavity of the mold. An end mill, for example, can be mentioned as tool 12 . The outer diameter of the end mill 12 is, for example, about 1 mm, and the rotation speed of the end mill 12 during cutting is about 60,000 rpm.

Here, the spindle head 4 of the machine tool 2 will be described in more detail with reference to FIG. 5(a).

The spindle head 4 is of a built-in motor type, and comprises a housing 31 and a spindle (spindle) 11 . The main shaft 11 is formed in a columnar shape and is rotatably supported by the housing 31 by an air bearing. Reference symbol C1 indicates the rotation center axis of the main shaft 11 .

A tool holding portion 33 is provided at one end (lower end in FIG. 5A) of the main shaft 11 in the longitudinal direction (extending direction of the rotation center axis C1; Z direction). The tool 12 can be attached to and detached from the spindle 11 by providing the tool holding portion 33 . A rotor 37 of a motor 35 is integrally provided at the other longitudinal end of the main shaft 11 (upper end in FIG. 5A). A stator 39 of the motor 35 is provided outside the rotor 37 . The stator 39 is provided integrally with the housing 31 slightly apart from the rotor 37 .

Next, a tool shape measuring device 1a according to a second embodiment of the present invention will be described in detail.

A tool shape measuring device 1a is a device for measuring the shape of a tool 12 installed on a spindle 11 of a machine tool 2 in the same manner as the tool shape measuring device 1 according to the first embodiment of the present invention. , includes a camera 22, a spindle rotation angle sensor (spindle rotation angle detection sensor) 41, and a control device 20 (see FIG. 1).

The camera 22 captures the rotating tool 12 to obtain an image (still image) of the tool 12 . The camera 22 is, for example, a digital camera and is adapted to photograph the tool 12 with a global shutter. The shutter speed of the camera 22 when photographing the tool 12 (exposure time of the imaging element 75 of the camera 22 shown in FIG. 7) is set to a short time such that the image of the rotating tool 12 becomes a substantially still image. there is

The spindle rotation angle sensor 41 detects the rotation angle of the spindle 11 (the tool 12 installed on the spindle 11). Further, the spindle rotation angle sensor 41 outputs a continuous pulse signal (see FIG. 5(c) and FIG. 10) while the spindle 11 is rotating, and outputs a pulse of one cycle each time the spindle 11 makes one rotation. configured to emit a signal. Since the spindle 11 rotates at a constant speed, the cycle of the continuous pulse signal has a constant value.

The spindle rotation angle sensor 41 will be described in more detail with reference to FIGS. 5(a) and 5(b). The spindle rotation angle sensor 41 includes, for example, a reflective photoelectric sensor 43 and a mark 45 .

The photoelectric sensor 43 is provided integrally with the housing 31 . The mark 45 is provided integrally with the main shaft 11, for example, over the half circumference (see the portion indicated by the dashed line in FIG. 5B). When the spindle 11 rotates, the photoelectric sensor 43 repeats the state in which the mark 45 is detected and the state in which it does not, so that the photoelectric sensor 43 emits a continuous pulse signal as shown in FIG. 5(c). It's becoming

As already understood, the resolution of the rotation angle of the spindle 11 by the spindle rotation angle sensor 41 is extremely large, 180°.

The control device 20 outputs a photographing command to the camera 22 according to the rotation angle of the main shaft 11 detected by the main shaft rotation angle sensor 41 . For example, when the spindle rotation angle sensor 41 detects the mark 45, a photographing command is output.

It is assumed that the tool 12 is installed at a predetermined rotation angle with respect to the main shaft 11 . For example, when viewed in the extending direction (Z direction) of the rotation center axis C1, the angle (phase) of the end of the mark 45 (the front end in the rotation direction of the main shaft 11) and the tip 47 of the cutting edge of the tool 12 (Fig. 3 , FIGS. 4 and 6) coincide with each other.

The tip 47 of one cutting edge of the two-bladed tool 12 is formed linearly but is located on one plane, and the tip 47 of the other cutting edge of the two-bladed tool 12 is also Assume that they are located on the one plane described above. The tip 47 of the cutting edge of the tool 12, which is formed in a linear shape, does not have to be positioned strictly on one plane, and may be positioned on one plane. For example, when viewed in the Z direction, the tip 47 of one cutting edge of the tool 12 may be positioned inside a sector with a central angle of about 1° to 5°. Assuming that the point where the two line segments (radii) of the sector intersect is the central angle forming point of the sector, the central angle forming point of the sector and the rotation center axis C1 of the tool 12 coincide with each other. there is

More specifically, the rotation center axis C1, the end of the mark 45, and the tip 47 of the cutting edge of the tool 12 are on one straight line when viewed in the extending direction (Z direction) of the rotation center axis C1. The tool 12 has a plurality (two or three) of cutting edge tips 47, but one tip 47 of the plurality of cutting edge tips 47, the rotation center axis C1, and the end of the mark 45 are one. should be on the straight line of

Alternatively, the mark 45 may be provided on a portion other than the cutting edge of the tool 12 instead of the spindle 11 , and the photoelectric sensor 43 may detect the mark 45 provided on the tool 12 . Accordingly, when installing the tool 12 on the spindle 11, there is no need to worry about the installation angle of the tool 12, and the installation of the tool 12 on the spindle 11 is facilitated.

Furthermore, the rotation angle of the tool 12 installed on the spindle 11 may be detected by detecting the tip 47 of the cutting edge of the tool with a sensor such as a photoelectric sensor 43 or a proximity sensor without providing a mark. good. In this case, if the end mill 12 has two blades, a pulse signal of two cycles is generated each time the spindle 11 makes one rotation, and if the end mill 12 has three blades, the spindle 11 makes one rotation. A pulse signal of three cycles is emitted every time.

Further explaining the control device 20, the control device 20 issues a command to photograph the rotating tool 12 according to the values of the rotation angles of the spindle 11 and the tool 12 detected by the spindle rotation angle sensor 41 (photographing). It is configured to send a command (shooting command signal) to the camera 22 . The camera 22 that has received the photographing command immediately photographs the rotating tool 12 to obtain a still image of the tool 12 . A still image of the maximum outer shape of the tool 12 at the tip 47 of the cutting edge of the rotating tool 12 is then obtained. The rotation angle of the spindle 11 and the tool 12 at which a still image of the maximum outline can be obtained is defined as the maximum rotation angle. The maximum rotation angle corresponds to the tool reference angle described in the first embodiment.

A static image of the maximum contour of the tool 12 at the tip 47 of the cutting edge of the rotating tool 12 will now be described in more detail, taking a ball end mill as an example.

First, the ball end mill 12 will be explained. As shown in FIG. 9A, the ball end mill 12 has a cutting edge (indicated by a dashed line) on its outer circumference. In addition, since the shape of the end mill 12 is simplified in FIG. 9, the cutting edges and grooves are omitted.

The ball end mill 12 includes a cylindrical base end portion 49 and a hemispherical tip end portion 51 as shown in FIG. 9(a). The outer diameter of the proximal end portion 49 and the diameter of the distal end portion 51 match each other, and the distal end portion 51 is located at one end (lower end) of the extending direction (Z direction) of the central axis C1 of the proximal end portion 49. It has a sticky shape. Assuming that the center of the circular end surface of the hemispherical distal end portion 51 (the circular flat surface attached to the circular flat surface of the cylindrical base end portion 49) is the center C2 of the distal end portion 51, the center C2 is the ball. It exists on the central axis C<b>1 of the end mill 12 .

The cutting edge of the ball end mill 12 is formed on the outer periphery of the tip portion 51 and the end portion of the base end portion 49 (the end portion on the tip portion 51 side). The ball end mill 12 is held by the tool holding portion 33 with the other end of the base end portion 49 engaged with the tool holding portion 33 .

The ball end mill 12 held by the tool holding portion 33 of the spindle 11 rotates together with the spindle 11 (rotates around the central axis C1), thereby cutting the workpiece (work) 14 with the cutting edge. It is designed to be processed.

Next, the processing points when the workpiece 14 is cut by the ball end mill 12 will be described. When the workpiece 14 is cut by the cutting edge of the ball end mill 12, the point of contact between the tip 47 of the cutting edge of the ball end mill 12 and the workpiece 14 becomes the machining point.

More specifically, when the ball end mill 12 is used to cut the workpiece 14 with a predetermined depth of cut, the ball end mill 12 moves in the X, Y, and Z directions with respect to the workpiece 14. ing. During this machining, for example, the point at which the ball end mill 12 is in contact with the workpiece 14 at the rear end in this moving direction (the point at which the outer shape of the workpiece 14 is determined after machining) is the machining point. become. A machining point is formed at a portion of the tip 47 of the cutting edge of the ball end mill 12 .

Next, a still image of the maximum outer shape of the ball end mill 12 at the tip 47 of the cutting edge of the rotating ball end mill 12 will be described.

Rotation causes the position of the cutting edge of the ball end mill 12 to change over time. For example, in the case of a two-blade ball end mill 12, one of the two cutting edges makes one revolution for each revolution of the ball end mill 12. When the two-bladed ball end mill 12 is viewed in the extending direction of the rotation center axis C1, a pair of cutting edges are formed so as to be point-symmetrical with respect to the rotation center axis C1 (FIGS. 3 and 6). , see FIG. 7).

When one cutting edge of the rotating ball end mill 12 is viewed in the Z direction or the Y direction, the distance between the tip 47 of the cutting edge and the rotation center axis C1 (for example, distance in the X direction) changes. 6(a), reference sign Lb in FIG. 6(b), reference sign Lc in FIG. 6(c), and reference sign Ld in FIG. directional distance. 6, the tool 12 rotates counterclockwise as shown by the arrow in FIG. 6(c), the state shown in FIG. 6(d), the state shown in FIG. 6(a), and so on are repeated in this order.

Then, at a certain time (time shown in FIGS. 6(b) and 6(d)), the value of the distance between the tip 47 of one cutting edge of the ball end mill 12 and the rotation center axis C1 reaches a maximum. values Lb and Ld. A still image of the ball end mill 12 at the maximum values Lb and Ld is a still image of the maximum outer shape of the ball end mill 12 at the tip 47 of one cutting edge of the rotating ball end mill 12 .

Also, in the case of the other cutting edge of the two cutting edges, similarly to the one cutting edge, at a certain time, the tip 47 of the other cutting edge of the ball end mill 12 and the rotation center axis C1 The maximum value is the distance between The static image of the ball end mill 12 at this maximum value is the maximum outer shape static image of the ball end mill 12 at the tip of the other cutting edge of the rotating ball end mill 12 .

The contour (outer circumference; linear edge) of the cutting edge of the ball end mill 12 obtained in these still images of the maximum contour shows the tip 47 of the cutting edge of the ball end mill 12 .

In fact, as shown in FIG. 9(d), the tip 47 (47A) of one cutting edge and the tip 47 (47B) of the other cutting edge are very slightly with respect to the rotation center axis C1. ) are often asymmetrical. In this case, the still image of the maximum outer shape of the ball end mill 12 at the tip 47 of the cutting edge is the tip 47 of the pair of cutting edges that has the larger value of the distance from the rotation center axis C1. .

In addition, the two-dot chain line of FIG.9(d) arrange|positions 47 A of front-end|tips of one cutting edge symmetrically with respect to the rotation center axis C1. In FIG. 9(d), the tip 47B of the other cutting edge is located inside the tip 47A of one cutting edge, but the tip 47B of the other cutting edge is part of one cutting edge. It may be located outside the tip 47A. In this case, a still image of the maximum profile of the ball end mill 12 at the tip 47 of the cutting edge is formed by part of the tip 47A of one cutting edge and part of the tip 47B of the other cutting edge.

Also, when photographing the ball end mill 12 having two cutting edges, a still image of the maximum outer shape of the ball end mill 12 is obtained by photographing with the camera 22 each time the ball end mill 12 makes a half rotation (180° rotation). It's like When photographing the ball end mill 12 having three cutting edges, a still image of the maximum outer shape of the ball end mill 12 is obtained by photographing with the camera 22 each time the ball end mill 12 rotates ⅓ (120° rotation). It's like Furthermore, when photographing the ball end mill 12 having n cutting edges, the camera 22 photographs each time the ball end mill 12 rotates 1/n (360°/n), and the maximum outer shape of the ball end mill 12 remains stationary. I'm getting an image.

The spindle rotation angle sensor 41 is configured to also detect the rotation speed (rotational angular velocity) of the spindle 11 . As described above, the spindle rotation angle sensor 41 is configured to emit, for example, a rectangular wave-like continuous pulse signal from the spindle 11 rotating at a constant number of revolutions. The control device 20 receives the continuous pulse signal emitted by the spindle rotation angle sensor 41, and measures the time interval (cycle of the continuous pulse signal) of the continuous pulse signal that is turned on and off per predetermined time. The rotational speed of the spindle 11 is detected.

Instead of the control device 20, the spindle rotation angle sensor 41 is configured to detect the number of revolutions of the spindle 11 by measuring the time intervals of the continuous pulse signals that are turned on and off. may

The control device 20 changes the timing of outputting a photographing command to the camera 22 according to the rotation speed (rotational angular velocity) of the main shaft 11 .

The control device 20 changes (adjusts) the timing of outputting the photographing command to the camera 22 in order to obtain a still image of the maximum outline of the tool 12 at the tip 47 of the cutting edge of the rotating tool 12 . That is, this is done to obtain a still image of the tool 12 at the maximum rotation angle.

To explain further, there is a slight delay (shooting time lag; delay time) from when the control device 20 outputs a shooting command to the camera 22 until the camera 22 actually shoots. For example, when the tool 12 reaches a rotation angle at which a still image of the maximum outer shape of the tool 12 at the tip 47 of the cutting edge of the tool 12 can be obtained, even if a photographing command is output from the control device 20 to the camera 22, the actual It takes a short time for the camera 22 to photograph the tool 12 immediately. During this short period of time, the tool 12 rotates slightly, and a still image of the maximum profile of the tool 12 at the tip 47 of the cutting edge of the tool 12 cannot be obtained.

Description will be made with reference to FIG. FIG. 6 is a diagram of the two-bladed tool 12 viewed in the Z direction. In the mode shown in FIG. 6, it is assumed that the tool 12 rotates 60,000 times per minute in the direction indicated by the arrow. As described above, time passes from FIG. 6(a) to FIG. 6(d).

State 1 shown in FIG. 6(a) indicates a case where the delay is "0 μsec", and state 2 shown in FIG. 6(b) indicates a case where the delay is "250 μsec". State 3 shown in (c) indicates a case where the delay is "500 μsec", and state 4 shown in FIG. 6(d) indicates a case where the delay is "750 μsec".

For example, when the delay is "250 μsec", if a photographing command is output in state 1, the tool 12 at the rotation angle of state 2 is photographed.

"Lighting" in FIG. 6 indicates a light emitting device 61, which will be described later. Further, as described above, still images of the maximum outer shape of the tool 12 can be obtained by photographing in states 2 and 4 of FIGS. 6(b) and 6(d).

If there is an imaging time lag, it becomes impossible to obtain a still image of the maximum outer shape of the tool 12 at the tip 47 of the cutting edge of the tool 12 .

Therefore, the timing of outputting the photographing command to the camera 22 is adjusted using the photographing time lag obtained in advance (the photographing time lag time stored in the memory of the control device 20). For example, a photographing command may be output to the camera 22 at a time preceding the time at which a still image of the maximum outer shape of the tool 12 at the tip 47 of the cutting edge of the tool 12 is reached by the time of the photographing time lag. It has become.

Here, the adjustment of the timing of outputting the photographing command to the camera 22 will be described in detail with reference to FIG.

The horizontal axis of FIG. 10 indicates the passage of time t, and the vertical axis indicates the ON/OFF state of the continuous pulse signal generated by the spindle rotation angle sensor 41 .

In FIG. 10A, for example, it is assumed that the spindle 11 and the tool 12 reach their maximum rotation angles at time t1. The spindle rotation angle sensor 41 starts to emit an ON signal at time t1, stops sending the ON signal at time t2, starts sending an ON signal at time t3, and stops sending the ON signal at time t4. It's like

What is indicated by reference symbol TF in FIG. 10(a) is the time indicating one period in the continuous pulse signal. What is indicated by reference symbol TD in FIG. 10(a) is the time of the shooting time lag. When the control device 20 outputs a photographing command to the camera 22 at time t1, the time at which the camera 22 photographs the tool 12 becomes the time indicated by reference symbol TD. With this, a still image of the maximum outer shape of the tool 12 cannot be obtained.

Therefore, when the control device 20 outputs a photographing command to the camera 22 at time td1, which is the time TD before time t1, the time at which the camera 22 photographs the tool 12 becomes time t1, and the still image of the maximum outer shape of the tool 12 is reached. can be obtained.

Note that when the control device 20 outputs a photographing command to the camera 22 at time td2, which is the time (TF-TD) after time t1, the time at which the camera 22 photographs the tool 12 becomes time t3. A still image of the maximum contour of the tool 12 can be obtained.

By the way, in FIG. 10A, the time TD of the imaging time lag is shorter than the time TF representing one cycle of the continuous pulse signal, but the time TD may be longer than the time TF.

This case will be described with reference to FIG. 10(b). In FIG. 10(b), "TF<TD<2×TF" is established, but the same can be applied even if the above "2" is a natural number equal to or greater than "3".

In FIG. 10B, the control device 20 outputs a photographing command to the camera 22 at time td2, which is the time (2×TF−TD) after time t1. As a result, the time when the camera 22 photographs the tool 12 is time t5, and a still image of the maximum outer shape of the tool 12 can also be obtained.

In the mode shown in FIG. 10(b), even if the control device 20 outputs a photographing command to the camera 22 at a time (not shown in FIG. 10(b)) which is a time TD before the time t1, good. In this case, the time when the camera 22 photographs the tool 12 is time t3.

Also, in FIGS. 10A and 10B, “TF-TD” and “2×TF-TD” may be replaced with “n×TF-TD”. However, "n" is an arbitrary natural number.

Next, an example of how to determine the time TD of the shooting time lag will be described.

A dummy tool (not shown) with one mark (not shown) is installed on the tool holding portion 33 of the spindle 11, and the dummy tool is rotated at a constant number of revolutions. Then, when the spindle rotation angle sensor 41 detects that the rotation angle of the dummy tool has reached a predetermined rotation angle (rotation angle to be photographed), the control device 20 outputs a photographing command to the camera 22, and the camera 22 obtains a still image of the dummy tool photographing the dummy tool.

By detecting the positional deviation amount of the mark (not shown) appearing in the still image, the photographing time lag time TD is obtained.

For example, in a state in which the dummy tool is rotating at 60,000 rpm, the spindle rotation angle sensor 41 detects that the rotation angle of the mark of the dummy tool has become "0°". A still image of the dummy tool is obtained by outputting a photographing command to the camera 22 and photographing the dummy tool. If the rotation angle of the mark appearing in the obtained still image is "45°", the shooting time lag time TD is 125 μsec, and if the rotation angle is "90°" , the photographing time lag time TD is 250 μsec.

In the tool shape measuring apparatus 1a, for example, the time lag time TDa when the spindle 11 rotates at a constant rotation speed na is measured, and the time lag time TDa when the spindle 11 rotates at another constant rotation speed nb is measured. TDb is calculated from the time lag time TDa. That is, "time lag time TDb=time lag time TDa×constant number of revolutions nb/constant number of revolutions na".

In addition, in the tool shape measuring device 1a, the time lag times TDa1, TDa2, TDa3, . Alternatively, the time lag time TDb when the main shaft 11 is rotating at another constant rotation speed nb may be obtained as follows. However, na1<na2<na3 . . . and TDa1>TDa2>TDa3 .

When the constant rotation speed nb matches one of the constant rotation speeds na1, na2, na3, .

Also, when the constant rotation speed nb does not match any one of the plurality of constant rotation speeds na1, na2, na3, . For example, "TDb=TDa1+((nb-na1)/(na2-na1))×(TDa2-TDa1)".

If the value of the time lag time TD is large and the main shaft 11 rotates 60,000 times per minute, the main shaft 11 may rotate 360° or more within the time lag time TD. In this case, the spindle 11 is first rotated at a low rotation speed to obtain the time lag time TD, and then the rotation speed of the spindle 11 is gradually increased to obtain the time lag time TD. is rotated by 360° or more.

Also, the one shown in FIG. 11 may be employed as a dummy tool. A dummy tool 63 shown in FIG. 11 has a plurality of marks 67 (67A, 67B, 67C, 67D, . The marks 67 are arranged at regular intervals in the circumferential direction (horizontal direction in FIG. 11B) of the cylindrical dummy tool body 65 . The marks 67 (67A, 67B, 67C, 67D, . 11B, the distance from the lower end in the Z direction gradually increases from left to right in FIG. 11(b).

In the above description, the main shaft rotation angle sensor 41 emits a pulse signal of one cycle each time the main shaft 11 makes one rotation. (not shown) may be provided to detect the rotation angle of the main shaft 11 . Assume that the resolution of the rotary encoder is sufficiently smaller than the resolution of the spindle rotation angle sensor 41, for example, about 1°, or about 0.1° to 5°, or less. If such a rotary encoder is used, an appropriate image of the tool can be photographed by setting an appropriate rotary encoder value and outputting an image capturing command when that value is reached.

In the above description, the time lag is caused by the time from when the control device 20 outputs the shooting command to the camera 22 to when the camera 22 takes an image. The time lag caused by the control device 20 or the time lag caused by the control device 20 may be added to the time lag from when the control device 20 outputs a photographing command to the camera 22 until the camera 22 takes a photograph.

By the way, as the output of the photographing command by the control device 20, the first output and the second output may be mentioned.

The first output is for obtaining a plurality of images (still images of the plurality of tools 12) in a state where the main shaft 11 is rotated by a predetermined angle (for example, 1°). The still images of the plurality of tools 12 are images corresponding to one rotation of the spindle 11 .

By performing such a first output, the first photographing (first group of photographing) is performed, and for example, 360 images for one round of the tool 12 are photographed by the camera 22. It's becoming That is, assuming that the rotation angle of the spindle 11 at a certain predetermined rotation angle is a reference angle (0°), the image of the tool 12 when rotated 1° from the reference angle, and the tool 12 when rotated 2° from the reference angle 12 images, an image of the tool 12 rotated by 3° from the reference angle, and so on.

The angle of 1° is an angle at which the error of the photographed image (the image obtained by photographing by the camera 22) with respect to the actual shape of the tool 12 is within the allowable range.

In addition, since the spindle 11 rotates very quickly, the images are taken not 360 times during one rotation of the tool 12, but 360 times during multiple rotations of the tool 12. there is

An example will be given. Assuming that the reference angle (0°) of the main shaft is used, the first image is an image in which the main shaft 11 is rotated by 360°×m ₁ +1° from the reference angle. The second image is an image in which the main shaft 11 is rotated by 360°×m ₂ +2° from the reference angle. Hereinafter, the p-th image is an image in which the main shaft 11 is rotated by 360°×m _p +p° from the reference angle. However, _{m 1} , _{m 2} . . . _{mp .}

In the above description, m ₁ <m ₂ < . . . m _p . . . That is, in the above description, images are taken in order from the state in which the rotation angle of the tool 12 from the reference angle is small. However, this need not necessarily be the case. The images may be taken in an order regardless of the rotation angle of the tool 12 from the reference angle. For example, after 350° shooting, 10° shooting may be performed, and after 10° shooting, 121° shooting may be performed.

Also, the tool 12 rotated by 360°×m ₀ +1° from the time when the first photographing signal was output is photographed to obtain the first image of the tool 12, and the photographing of the first image is completed. Afterwards, the tool 12 rotated by 360°×m ₀ +2° from the output of the second photographing signal is photographed to obtain a second image of the tool 12, . . . The tool 12 rotated by 360°×m ₀ +p° from the time when the p-th photographing signal was output after the photographing of the −1st image was completed, and the p-th image of the tool 12 was photographed. . . . 360th photograph of the tool 12 rotated by 360°×m ₀ +360° from the time when the 360th photographing signal was output after the 359th photographing was completed. of the tool 12 may be obtained. It is necessary to set a sufficient time between photographing until the tool shape measuring device 1a finishes photographing the tool 12 and becomes ready for the next photographing. However, _m0 is a natural number.

A tool rotation angle input unit (not shown) for inputting the rotation angle of the tool 12 is provided in the tool shape measuring device 1a. The tool rotation angle input section is provided at the control device 20, for example.

Among the images obtained by the first output, the rotation angle of the tool 12 that is the desired rotation angle is input to the control device 20 from the tool rotation angle input section.

To explain further, the operator selects the angle of the tool 12 that needs to be photographed (a necessary image from among the plurality of images obtained by the first photographing) by looking at the first photographed image. Then, when it is desired to photograph only at this selected angle, the rotation angle of the tool 12 to be photographed is input from the tool rotation angle input section. For example, when photographing a tool with rotation angles of 1° and 2°, 1° and 2° are input using the tool rotation angle input section.

After the first output, the control device 20 is configured to perform the second output in order to photograph the tool 12 at the rotation angle input by the tool rotation angle input section.

By outputting such a second photographing command, the second photographing (second group photographing) is performed, and only the image of the tool 12 at the rotation angle desired to be photographed can be obtained.

After the control device 20 has made the first output, it is configured to make the second output in order to photograph the tool 12 at the rotation angle input by the tool rotation angle input section. Saves memory for storage.

Further, the tool shape measuring apparatus 1a is provided with a light emitting device (lighting device; for example, a strobe) 61 that emits light in synchronization with photographing by the camera 22. As shown in FIG. The stroboscope 61 is configured to emit light toward the tool 12 by outputting a photographing command to the camera 22 from the control device 20 . For example, an LED is employed as a light emitter (light source) of the strobe 61 .

The strobe 61 emits light to obtain a clearer still image of the tool 12 and to photograph the tool 12 in a shorter time. The time during which the strobe 61 emits light is shorter than the time during which the shutter of the camera 22 is open, and the strobe 61 emits light within the time during which the shutter of the camera 22 is open.

That is, the control device 20 outputs a shooting command to the camera 22 so that the strobe 61 emits light within the time the shutter of the camera 22 is open (the time the shutter of the camera 22 is fully open). ing.

In other words, when the control device 20 outputs a photographing command to the camera 22, the camera 22 immediately starts opening the shutter. The strobe 61 is configured to emit light at a time slightly after the camera 22 starts opening the shutter and before the camera 22 starts closing the shutter. there is

To explain further, an instruction (shooting command) may be given to the shutter of the camera 22 and the strobe 61 by triggering the measurement of the spindle rotation angle sensor 41, but the strobe 61 emits light before the shutter of the camera 22 is fully opened. Sometimes I put it away. In order to avoid this, the timing of light emission of the strobe 61 is delayed (a delay is inserted). Then, the strobe 61 is made to emit light at the timing when the shutter is fully opened.

This prevents the light emitting device 61 from emitting light before the shutter of the camera 22 is fully opened. In addition, the stroboscope 61 does not emit light when the shutter of the camera 22 is closed or in the middle of being closed.

When a still image of the tool 12 is obtained using the strobe 61 (by momentary light emission of the strobe 61), the camera 22 photographs the tool 12 with a slow shutter speed as described above. It should be noted that when an LED is adopted as the light emitting body of the strobe 61, the brightness of the LED is high and very bright, so it is not necessary to darken the photographing environment so much.

When a strobe 61 is provided, as shown in FIG. 7, the camera 22 is installed on one side of the rotating tool 12 and the strobe 61 is installed on the other side. The stroboscope 61 emits light toward the tool 12 and the camera 22 so that the tool 12 is photographed by the camera 22 . At this time, the strobe 61 is configured to emit parallel light 79 toward the tool 12 .

Thereby, when the tool 12 is photographed by the camera 22, the strobe 61 functions as a backlight, and the silhouette of the tool 12 is photographed by the camera 22. - 特許庁

To explain further, the traveling direction of the parallel light 79 emitted by the strobe 61 is, for example, the X direction, which is perpendicular to the rotation center axis C1 of the tool 12, and the optical axis 71 of the lens 69 of the camera 22 is also in the X direction. extended.

In addition, as shown in FIG. 7, an alignment adjusting device 73 for adjusting the alignment of the strobe 61 and the camera 22 with respect to the tool 12 may be provided. The alignment adjustment device 73 shown in FIG. 7 adjusts the rotation angle of the strobe 61 about a predetermined axis extending in the Z direction and the rotation angle of the strobe 61 about a predetermined axis extending in the Y direction. , the stroboscope 61 can be rotated and positioned. It is also assumed that the camera 22 is also provided with a similar alignment adjustment device.

The provision of the alignment adjusting device 73 makes it easy to adjust the traveling direction of the parallel light 79 emitted by the strobe 61 and the optical axis 71 of the lens 69 of the camera 22 so that they are parallel to each other. In addition, it becomes easy to make the traveling direction of the parallel light 79 emitted by the strobe 61 orthogonal to the plane of the imaging element 75 of the camera 22 .

Next, the operation of the tool shape measuring device 1a using the strobe 61 will be described.

In the initial state, the tool 12 rotates at a constant rotational speed, and the time lag time TD is determined in advance. 7, the tool 12 is positioned between the strobe 61 and the camera 22, and the alignment of the strobe 61 and the camera 22 with respect to the tool 12 is also adjusted.

In the above initial state, when the control device 20 issues a photographing command to the camera 22 using the time lag time TD, the shutter of the camera 22 opens, the strobe 61 emits light, and the shutter of the camera 22 closes. A still image of the maximum contour of the tool 12 is then obtained.

The actual shape of the tool 12 is obtained from the obtained still image of the maximum outer shape of the tool 12 . Then, for example, a still image of the ideal shape (target shape) of the tool 12 and the maximum outer shape of the tool 12 (image of the tool 12 for actually machining the workpiece 14) is displayed on a display screen (not shown) provided in the control device 20. shape) are superimposed and displayed.

Under the control of the control device 20 , the machine tool 2 processes the workpiece 14 while correcting the position of the tool 12 according to the actual shape of the tool 12 . Processing can take dozens of hours. During such machining, the shape of the tool 12 is measured by the tool shape measuring devices 1, 1a from time to time and used for correcting the tool 12 or checking whether the tool 12 needs to be replaced.

The rotation speed of the spindle 11 during machining is set by an NC (Numerical Control) device (control device 20). When the spindle 11 is rotated and reaches the number of revolutions for processing, the shape of the tool 12 is measured by the tool shape measuring devices 1 and 1a (before processing). A trigger for measurement (photographing of the tool 12 ) is a predetermined value of the spindle rotation sensor (encoder) or the spindle rotation angle sensor 41 . If the stroboscope 61 emits light at the same timing in synchronism with the trigger, an image of the tool 12 at the same angle can always be photographed during rotation at that number of rotations. As long as the tool 12 is not removed from the spindle 11, the rotation is stopped, and even when the original rotation speed is restored, the image of the tool 12 at the same angle can be photographed at the same timing.

According to the tool shape measuring apparatus 1a, the tool 12 is photographed by the camera 22 in accordance with the rotation angle of the spindle 11 detected by the spindle rotation angle sensor 41. Therefore, the time spent photographing the tool 12 is minimized. can be shortened. That is, since a still image of the tool 12 at the maximum rotation angle described above can be obtained by one photographing, the tool 12 is photographed a number of times and the still images obtained by these photographings are compared with each other. you don't have to.

If the shutter speed of the camera 22 is slowed down (for example, the shutter is open for a time longer than the time required for the tool 12 to rotate once) and the tool 12 is photographed, as shown in FIG. As a result, the reflection of the tool 12 becomes worse on the outer peripheral side of the tool 12, the contour 77 of the tool 12 becomes blurred, and the shape of the tool 12 cannot be accurately obtained.

On the other hand, if the tool shape measuring device 1a is used, as shown in FIG. 8(b), the blurring of the subject disappears and the contour 77 of the tool 12 becomes clear. A precise shape of the tool 12 can then be obtained.

Further, according to the tool shape measuring apparatus 1a, the timing at which the control device 20 outputs the photographing command to the camera 22 is changed according to the rotation speed of the main shaft 11, so that the rotation speed of the main shaft 11 changes. Even in this case, a still image of the maximum outer shape of the tool 12 can be easily obtained.

Further, according to the tool shape measuring apparatus 1a, the strobe 61 emits light toward the tool 12 in response to the output of the photographing command to the camera 22 by the control device 20. The tool 12 can be photographed in a shorter time than in the case of photographing with , and a clear image of the rotating tool 12 can be obtained inexpensively and easily. In other words, shortening the light emission time of the strobe 61 is cheaper and easier than shortening the shutter speed of the camera 22 (shortening the shutter open time).

Also, if the strobe 61 is not used, the shutter control of the camera 22 cannot follow, and even if it is possible, the camera will be very expensive. However, by using the strobe 61 capable of emitting light for a short period of time with a fast rise time, even if an inexpensive camera is used compared to a camera capable of high-speed shutter, the rotating tool 12 can be clearly seen. image can be obtained.

Further, according to the tool shape measuring apparatus 1a, the camera 22 is installed on one side of the rotating tool 12, and the strobe 61 is installed on the other side. Since the tool 12 is photographed by the camera 22 by emitting the parallel light 79 toward the camera 22, the silhouette of the tool 12 having no difference from the actual outer shape of the tool 12 can be photographed.

By obtaining the silhouette of the tool 12 as a still image, the outer circumference (edge; outline) 77 of the tool 12 becomes clear, and the accurate outer shape of the tool 12 can be easily obtained.

Further, according to the tool shape measuring apparatus 1a, the spindle rotation angle sensor 41 outputs a continuous pulse signal while the spindle 11 is rotating, and emits a pulse signal of one cycle each time the spindle 11 rotates. With such a configuration, it is possible to easily detect the rotation speed of the main shaft 11 rotating at high speed with a simple configuration.

By the way, although the end mill is listed as the tool 12, as the end mill, in addition to the ball end mill shown in FIG. 9 (a), the square end mill shown in FIG. 9 (b) and the radius end mill shown in FIG. 9 (c) are listed. can be done.

In the above description, the rotation angle and rotation speed of the spindle 11 and the tool 12 are detected using the spindle rotation angle sensor 41 and the rotary encoder. The configuration may be such that a signal similar to that of the angle sensor 41 or the rotary encoder is emitted to allow the camera 22 to take an image.

Further, all images obtained by photographing may be combined to obtain a still image of the maximum outer shape of the tool 12 . Then, tool correction may be performed based on the maximum outer shape of the tool 12 .

In addition, you may grasp the said description content as invention of the tool shape measuring method.

That is, a tool shape measuring method for measuring the shape of a tool (for example, an end mill) installed on a spindle of a machine tool, comprising: a spindle rotation angle detecting step of detecting the rotation angle of the spindle; A photographing step of photographing the tool with a camera according to the rotation angle of the spindle detected in the detecting step may be understood as a tool shape measuring method.

In this case, the main shaft rotation angle detection step is a step of detecting the rotation speed (rotational angular velocity) of the main shaft, and in the photographing step, the photographing timing is changed according to the rotation speed of the main shaft. may

Further, when the photographing is performed in the photographing step, a light emitting device may emit light toward the tool.

Further, in the photographing step, the light emitting device may emit light while the shutter of the camera is open.

In addition, a camera for photographing in the photographing process is installed on one side of the rotating tool, and the light emitting device is installed on the other side, and the light emitting device is connected to the tool ( and a camera), the tool may be photographed by the camera in the photographing step, and the light emitting device may emit parallel light toward the tool.

Further, in the main shaft rotation angle detection step, a continuous pulse signal is output while the main shaft is rotating (at a constant speed), and a pulse signal of one cycle is output each time the main shaft makes one rotation. It may be a process.

Further, as the photographing step, a first step and a second step are provided, and in the first step, a plurality of images are photographed in a state in which the main shaft is rotated by a predetermined angle, and the first step is performed. After photographing in , in the second step, only the image of the tool at a predetermined rotation angle may be photographed.

The entire contents of Japanese Patent Application No. 2018-203386 (filing date: October 30, 2018) are incorporated herein.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

Reference Signs List 1, 1a tool shape measuring device 2 machine tool 11 main shaft (spindle)
12 tool (end mill)
20 Control Device 22 Camera 41 Spindle Rotation Angle Sensor 61 Light Emitting Device (Strobe)

Claims (14)

A tool shape measuring device for measuring the shape of a tool installed on a spindle of a machine tool,
a camera for photographing the tool;
a spindle rotation angle sensor that detects the rotation angle of the spindle;
a control device that outputs a photographing command to the camera according to the rotation angle of the main shaft detected by the main shaft rotation angle sensor ;
The spindle rotation angle sensor is configured to output a continuous pulse signal while the spindle is rotating, and to emit a pulse signal of one cycle each time the spindle rotates,
The spindle rotation angle sensor is configured to also detect the rotation speed of the spindle,
The control device is configured to change the timing of outputting a photographing command to the camera according to the rotation speed of the main shaft,
A shooting time lag is defined as a time from when the control device outputs a shooting command to the camera to when the camera actually shoots,
The rotation angle of the tool at which a still image of the maximum outer shape of the tool at the tip of the cutting edge of the rotating tool can be obtained by shooting with the camera is defined as the maximum rotation angle,
The timing at which the control device outputs the photographing command is determined in advance from the time obtained by multiplying the time of the pulse signal for one cycle by an integer from the time when the rotation angle of the rotating tool reaches the maximum rotation angle. A tool shape measuring device characterized in that it is the time when the time obtained by subtracting the time of the photographing time lag has elapsed . The tool shape measuring device according to claim 1,
A tool shape measuring apparatus comprising a rotary encoder that detects the rotation angle of the spindle with finer resolution than the spindle rotation angle sensor . The tool shape measuring device according to claim 1 or 2,
Equipped with a light emitting device,
A tool shape measuring apparatus, wherein the light emitting device emits light toward the tool in response to an output of a photographing command to the camera by the control device. The tool shape measuring device according to claim 3,
A tool shape measuring apparatus, wherein the light emitting device emits light within a time period during which the shutter of the camera is open in response to an output of a photographing command to the camera by the control device. The tool shape measuring device according to claim 3 or 4,
The camera is installed on one side and the light emitting device is installed on the other side with the tool in between, and the light emitting device emits light toward the tool so that the camera can detect the It is configured so that the tool can be photographed,
A tool shape measuring apparatus, wherein the light emitting device is configured to emit parallel light toward the tool. The tool shape measuring device according to any one of claims 1 to 5,
A first output is provided as an output of a photographing command by the control device,
The tool shape measuring apparatus is configured to obtain a plurality of images in a state in which the spindle is rotated by a predetermined angle according to the first output. The tool shape measuring device according to claim 6 ,
a second output as an output of a photographing command by the control device;
A tool rotation angle input unit for inputting a rotation angle of the tool,
The control device is configured to output the second output in order to photograph the tool at the rotation angle input by the tool rotation angle input unit after outputting the first output. A tool shape measuring device characterized by: A tool shape measuring method for measuring the shape of a tool installed on a spindle of a machine tool,
a spindle rotation angle detection step of detecting the rotation angle of the spindle;
a photographing step of photographing the tool according to the rotation angle of the spindle detected in the spindle rotation angle detection step;
has
The step of detecting the spindle rotation angle is a step of outputting a continuous pulse signal while the spindle is rotating and outputting a pulse signal of one cycle each time the spindle rotates ,
The step of detecting the rotation angle of the main shaft is a step of also detecting the number of revolutions of the main shaft,
In the photographing step, the photographing timing is changed according to the number of revolutions of the main shaft,
A shooting time lag is defined as a time from when a shooting command is output to a camera in the shooting step to when the camera actually shoots,
The rotation angle of the tool at which a still image of the maximum outer shape of the tool at the tip of the cutting edge of the rotating tool can be obtained by shooting with the camera is defined as the maximum rotation angle,
The timing of outputting the photographing command in the photographing step is determined in advance from the time obtained by multiplying the time of the pulse signal for one cycle by an integer from the time when the rotation angle of the rotating tool reaches the maximum rotation angle. A tool shape measuring method , wherein the time obtained by subtracting the time of the photographing time lag obtained by subtracting the time has elapsed . The tool shape measuring method according to claim 8,
A tool shape measuring method , wherein a rotary encoder is used to detect the rotation angle of the spindle with finer resolution than the spindle rotation angle detection step . The tool shape measuring method according to claim 8 or 9,
A tool shape measuring method, wherein in the photographing step, a light emitting device emits light toward the tool when the photographing is performed. A tool shape measuring method according to claim 10 ,
In the photographing step, the tool shape measuring method is characterized in that the light emitting device emits light while the shutter of the camera is open. The tool shape measuring method according to claim 10 or 11,
A camera for photographing in the photographing process is installed on one side with the tool in between, and the light emitting device is installed on the other side, and the light emitting device emits light toward the tool. and wherein the tool is photographed by the camera in the photographing step, and the light emitting device emits parallel light toward the tool. The tool shape measuring method according to any one of claims 8 to 12,
As the imaging step, there is a first step,
The tool shape measuring method, wherein the first step is a step of photographing a plurality of images in a state in which the spindle is rotated by a predetermined angle. A tool shape measuring method according to claim 13 ,
As the imaging step, there is a second step,
The tool shape measuring method, wherein the second step is a step of photographing only an image of the tool at a predetermined rotation angle after photographing in the first step.

Images