KR20220154624A - Apparatus for detecting tool shape and method for detecting tool shape - Google Patents

Abstract

An apparatus for detecting the shape of a tool installed on a main shaft of a machine tool comprises: a camera for capturing an image of the shape; a specific vector acquisition unit for acquiring a specific vector at a plurality of points on the edge of the tool captured by the camera; a specific vector comparison unit for comparing a first plurality of specific vectors acquired by the specific vector acquisition unit at a first time with a second plurality of specific vectors acquired at a second time; and a tool shape determination unit for determining that the shape of the tool has changed when the values of the first plurality of specific vectors and the values of the second plurality of specific vectors differ from a predetermined threshold value as a result of the comparison in the specific vector comparison unit. The specific vector is a normal vector, a tangent vector, or a specific gradient vector inclined by a predetermined angle with respect to the normal vector. Accordingly, it is possible to detect the shape of a tool capable of measuring the shape of a tool whose shape is unknown and also detecting an abnormality in the shape of the tool.

Description

Apparatus for detecting the shape of a tool and method for detecting the shape of a tool

The following disclosure relates to a device for detecting the shape of a tool and a method for detecting the shape of a tool.

BACKGROUND ART [0002] In recent years, as the movement performance of devices (machine tools) improves in ultra-precision machining of workpieces, the shape accuracy of tools and the weight occupied by processing accuracy increase. In addition, tool shape measurement is performed using the tool shape measuring device disclosed in Patent Literature 1, for example.

International Publication No. 2020/090844

In general, when measuring the shape of a tool, the measuring instrument needs to specify what shape the tool is being measured. Usually, the shape of a tool to be defined (specified) is a shape of a tool on the market, such as a ball end mill shape, a radius end mill shape, and a flat end mill shape.

By the way, there are cases where a workpiece is processed using a tool having a special shape with an unknown shape, and it is sometimes desired to measure the shape of the tool having an unknown shape and also to detect abnormalities in the shape.

An object of the apparatus and method disclosed below is to provide a tool shape detecting device capable of measuring the shape of a tool whose shape is unknown and also detecting an abnormality in the shape of the tool, and a method for detecting the shape of the tool. was created by

According to a first aspect, an apparatus for detecting the shape of a tool installed on a main shaft of a machine tool includes: a camera for photographing the shape; and a specific vector for obtaining a specific vector at a plurality of points on an edge of the tool photographed by the camera. a vector acquisition unit and a specific vector comparison unit that compares a plurality of first specific vectors acquired at a first time point by the specific vector acquisition unit and a plurality of second specific vectors acquired at a second time point; When the value of the first plurality of specific vectors and the value of the second plurality of specific vectors differ from a predetermined threshold value as a result of comparison in the specific vector comparison unit, it is determined that the shape of the tool is changing. It has a tool shape determining unit, and the specific vector is a normal vector, a tangential vector, or a specific inclination vector inclined by a predetermined angle with respect to the normal vector.

According to a second aspect, an apparatus for detecting the shape of a tool installed on a main shaft of a machine tool includes: a camera for photographing the shape of the tool; A specific vector acquisition unit for obtaining a specific vector at a plurality of points, an edge shape acquisition unit for obtaining an edge of the tool by photographing the tool with the camera after use of the tool, and a specific vector obtained by the specific vector acquisition unit and a tool shape change amount acquisition unit that obtains a change amount of the tool shape after use with respect to the tool shape before use, using the edge of the tool obtained by the edge shape acquisition unit, wherein the specific vector is a normal vector or It is a tangential vector or a specific inclination vector inclined by a certain angle with respect to the normal vector.

According to a third aspect, an apparatus for detecting the shape of a tool installed on a main shaft of a machine tool includes: a camera for photographing the shape of the tool; and before use of the tool, the camera photographs the tool to determine the edge of the tool. An edge shape acquisition unit to obtain, a specific vector acquisition unit to obtain a specific vector at a plurality of points on the edge of the tool by photographing the tool with the camera after the tool is used, and a specific vector obtained by the specific vector acquisition unit and a tool shape change amount acquisition unit that obtains a change amount of the tool shape after use with respect to the tool shape before use, using the edge of the tool obtained by the edge shape acquisition unit, wherein the specific vector is a normal vector or It is a tangential vector or a specific inclination vector inclined by a certain angle with respect to the normal vector.

According to a fourth aspect, a method for detecting the shape of a tool installed on a main shaft of a machine tool includes a specific vector acquisition step of obtaining these specific vectors from a plurality of points on the edge of the tool captured by a camera that photographs the shape of the tool and a specific vector comparison step of comparing the first plurality of specific vectors acquired in the specific vector acquisition step with the second plurality of specific vectors acquired next in the specific vector acquisition step, and the comparison in the specific vector comparison step. As a result, when the values of the first plurality of specific vectors and the values of the second plurality of specific vectors differ from a predetermined threshold value, a tool shape determining step of determining that the shape of the tool is changing, and The vector is a normal vector or a tangential vector or a specific slope vector inclined by a certain angle with respect to the normal vector.

According to the disclosed device or method, it is possible to measure the shape of a tool whose shape is unknown and to detect the shape of a tool capable of detecting an abnormality in the shape of the tool.

1 is a diagram showing a schematic configuration of a device for detecting the shape of a tool according to an embodiment and a machine tool to which the device is installed.
2 is a diagram showing a schematic configuration of a device for detecting the shape of a tool.
Fig. 3 is a diagram showing the edge and normal vector of a tool obtained by the device for detecting the shape of the tool.
FIG. 4 is an enlarged view showing a part of the edge of the tool and this normal vector in FIG. 3 .
Fig. 5 is a diagram showing the edge and normal vector of the tool before and after use.
Fig. 6 is a diagram showing components of the normal vector shown in Fig. 5;
Fig. 7 is an enlarged view showing a part of the edge of the tool and this normal vector in Fig. 5;
8 is a flowchart showing the operation of the device for detecting the shape of a tool.

Some exemplary embodiments are described below with reference to the accompanying drawings.

The device 1 (tool shape abnormality detection device) for detecting the shape of a tool according to one embodiment is installed and used in a machine tool 2, as shown in FIG. 1, for example.

The machine tool 2 has a table 16 and a gate-shaped column 10 on the upper surface of a bed 18, and a spindle head 4 is connected to a cross rail 8 of the column 10 via a saddle 6. is supported. The main shaft 11 is supported by the main shaft head 4 .

Here, for convenience of description, one horizontal predetermined direction is referred to as the X direction (X-axis direction), and another predetermined horizontal direction orthogonal to the X direction is referred to as the Y-direction (Y-axis direction). The vertical direction orthogonal to the direction is referred to as the Z direction (Z-axis direction).

The table 16 is movable relative to the bed 18 in the X-axis direction. The saddle 6 is movable along the cross rail 8 in the Y-axis direction. The main shaft head 4 is movable in the Z-axis direction with respect to the saddle 6.

By moving these three axes, it is possible to move the tool (for example, an end mill) 12 three-dimensionally with respect to the workpiece 14 loaded on the table 16, and to process the workpiece 14. At the end of the table 16, a device 1 for detecting the shape of a tool is installed. The control device 20 is connected to the device 1 for detecting the shape of the machine tool 2 and the tool, and can control the device 1 for detecting the shape of the machine tool 2 and the tool. In addition, the control device 20 is equipped with a CPU and memory not shown.

Fig. 2 shows a view in which the shape of the tool 12 is measured by the device 1 for detecting the shape of the tool. The tool 12 is moved to the position shown in FIG. 2 by the three axes described above, and the shape of the tool 12 is measured. The device 1 for detecting the shape of a tool includes a camera 22 and a lighting device 24, and as shown in FIG. 2 , the tool 12 includes a camera 22 and a lighting device 24. The shape of the tool 12 is measured in a state of being positioned between them. Since light from the lighting device 24 is projected from behind the tool 12 to capture an image, the shape of the tool 12 is captured as a shadow.

The camera 22 is equipped with a high-speed shutter, so that even when the tool 12 is rotating at several thousand revolutions/minute, it is possible to take pictures like still images. In addition, a zoom lens may be provided in the camera 22, and the control device 20 may be capable of controlling the magnification. The main shaft 11 is equipped with a rotation angle sensor (not shown), and the control device 20 can perform control such as position determination of rotation speed and rotation angle.

When the tool 12 rotates at a rotational speed of 10,000 revolutions/minute or more, it is difficult to cope with only a high-speed shutter. In this case, the lighting 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 tool 12 while rotating. In addition, the maximum rotational speed of the tool 12 can be set to about 120,000 rotations/minute.

The tool 12 is used, for example, when forming the core of a mold or the surface of a cavity by cutting. The cutting process is performed to perform, for example, final finishing on the surface of the core or cavity of the mold, and the surface of the core or cavity of the mold becomes mirror-like by the cutting process. The outer diameter of the end mill 12 is, for example, about 1 mm, and the number of revolutions of the end mill 12 during cutting is about 60,000 revolutions/minute.

By the way, by photographing the tool 12, a still image of the maximum external shape of the end mill 12 can be obtained. This is because the location of the largest external shape is the cutting edge of the end mill 12, and the shape of the cutting edge affects the shape of the processing surface of the workpiece 14. Further, details of shooting of the tool 12 are disclosed in International Publication No. 2020/090844.

As the device 1 for detecting the shape of a tool, a tool shape measuring device disclosed in International Publication No. 2020/090844 is employed. A device 1 for detecting the shape of a tool is a tool (for example, a cutting tool such as a rotating end mill) 12 installed on a main shaft 11 of a machine tool (for example, an ultra-precision machine) 2. detect the shape.

As shown in FIG. 2 , the apparatus 1 includes a control unit 25 and a camera (digital camera) 22 that photographs the shape of the tool 12 . The control unit 25 may be part of the control device 20 , for example, but the control unit 25 may be provided separately from the control device 20 .

Device 1 is a device for detecting the shape of a tool 12 mounted on a main shaft 11 of a machine tool (precision machining machine) 2 . The tool 12 installed on the main shaft 11 of the machine tool 2 rotates around a predetermined central axis C1. Then, while the tool 12 rotates, the workpiece 14 is cut.

In addition, as shown in FIG. 2, the device 1 includes a normal vector acquisition unit (specific vector acquisition unit) 27, a normal vector comparison unit (specific vector comparison unit) 29, and a tool shape determination unit 31 ) is provided.

The normal vector acquisition unit 27 captures these normals at a plurality of points on the edge (outer circumferential portion corresponding to the tip of the cutting edge; edge of the maximum external shape) 13 of the tool 12 photographed by the camera 22. to find a vector. A plurality of points on the edge 13 of the tool 12 are indicated by reference numerals P _n-1 , P _n , P _n+1 , P _n+2 . . . is indicated by A plurality of normal vectors are reference numerals VP _n-1 , VP _n , VP _n+1 , VP _n+2 . . . is indicated by In addition, the edge 13 of the tool 12 is obtained by the edge shape acquisition unit 33 .

A plurality of points on the edge 13 of the tool 12 are arranged in order in the elongation direction of the edge 13 at a very small distance from each other, for example, constant. As the constant extremely small distance, a distance equivalent to the pitch of pixels of the imaging device of the camera 22 is exemplified. The constant, extremely small distance may be slightly larger than the pixel pitch.

In addition, instead of obtaining a normal vector in the normal vector acquiring unit 27, a vector (specific gradient vector) inclined at a certain angle with respect to the normal vector may be obtained. That is, a vector that intersects the normal vector at a constant angle may be obtained. For example, a tangent vector (tangent vector) orthogonal to the normal vector may be obtained. Here, a normal vector, a specific slope vector, and a tangential vector are designated as specific vectors. In the normal vector acquisition unit, the inclination of the tangent line of the edge 13 or the inclination of the normal line at each of a plurality of points on the edge 13 of the tool 12 may be obtained.

The normal vector comparator 29 compares a plurality of first normal vectors acquired at the first time point by the normal vector acquisition section 27 with a plurality of second normal vectors similarly obtained at the second time point. is supposed to do The plurality of first normal vectors are, for example, a plurality of normal vectors at the starting point before cutting of the workpiece 14 by the tool 12, and the plurality of second normal vectors are, for example, in the tool 12 are a plurality of normal vectors at the time point after the cutting of the workpiece 14 by

The tool shape determination unit 31 determines, as a result of comparison by the normal vector comparison unit 29, that the values of the first plurality of normal vectors differ from the values of the plurality of second normal vectors by a predetermined threshold value, It is made to judge that the shape of (12) is changing.

Here, normal vectors VP _n-1 , VP _n , VP _n+1 , VP _n+2 . . . The acquisition of is described in more detail by taking the normal vector VP _n+1 as an example with reference to FIG. 4 .

First, a line segment LA _n connecting two adjacent points P _n on the edge 13 of the tool 12 and the point P _n+1 is obtained. Further, a line segment LA _n+1 connecting two adjacent points P _n+1 and P _n+2 on the edge 13 of the tool 12 is obtained. Subsequently, the normal vector VP _n+1 with the point P _n+1 as the starting point, with the intersection angle with the line segment LA _n being α _n+1 and the intersection angle with the line segment LA _n being β _n+1 , is obtained. The normal vector VP _n+1 is directed toward the center side of the tool 12 (the rotation center axis C1 side). In addition, the intersection angle α _n+1 and the intersection angle β _n+1 are equal to each other.

Other normal vectors are also obtained in the same way as the normal vector VP _n+1 . Further, a plurality of normal vectors VP _n-1 , VP _n , VP _n+1 , VP _n+2 . , the absolute values (scalar amounts) of each other are equal. Multiple normal vectors VP _n-1 , VP _n , VP _n+1 , VP _n+2 . is a unit vector, for example.

In addition, a ray may be obtained instead of a line segment LA _n or the like from a plurality of points (point P _n or the like) by the least square method or the like to obtain a normal vector VP _n or the like. That is, in FIG. 4, instead of the line segment LA _n+1 , the first half-line extending obliquely upward (to the point P _n+1 side) from the point P _n+2 is obtained. This ray can be obtained by the least squares method from a plurality of points (for example, two points P _n+1 , P _n ). In the same way, a second ray extending from point P _n+2 obliquely downward (to the point P _n+3 side) is obtained. Then, the intersection angle of the first ray is α _n+2 , the intersection angle with the second ray is β _n+2 , and the normal vector VP _n+2 with the point P _n+2 as the starting point is obtained. In addition, the intersection angle α _{n + 2} and the intersection angle β _{n + 2} are equal to each other. Other normal vectors are obtained similarly using half lines.

Next, the comparison between the plurality of first normal vectors and the plurality of second normal vectors in the normal vector comparing unit 29 will be described in more detail with reference to FIGS. 5 and 6 . The solid line shown in FIG. 5 represents the edge 13 of the tool (tool before use) 12 relating to the first plurality of normal vectors. The broken line shown in FIG. 5 represents the edge 13a of the tool (tool after use) 12 related to the second plurality of normal vectors. In addition, in FIG. 5, part of the broken line 13a is spaced apart from the solid line 13, and the other part of the broken line 13a overlaps the solid line 13.

The first plurality of normal vectors are reference symbols VP _n , VP _n+1 , VP _n+2 , VP _n+3 , VP _n+4 . , and the second plurality of normal vectors are reference numerals VQ _n , VQ _n+1 , VQ _n+2 , VQ _n+3 , VQ _n+4 . is indicated by Second normal vectors VQ _n , VQ _n+1 , VQ _n+2 , VQ _n+3 , VQ _n+4 . can be obtained in the same way as the first normal vector, and is, for example, a unit vector, similarly to the first normal vector.

6 shows a first plurality of normal vectors VP _n , VP _n+1 , VP _n+2 , VP _n+3 , VP _n+4 . Each component and the second plurality of normal vectors VQ _n , VQ _n+1 , VQ _n+2 , VQ _n+3 , VQ _n+4 . Each component is shown.

For example, the components of normal vector VP _n+1 are denoted (Pa _n+1 , Pb _n+1 ), and the components of normal vector VQ _n+1 are (Qa _n+1 , Qb _n+1 ) is indicated.

The normal vector comparator 29 compares the value of Pa _n+1 /Pb _n+1 (the direction of the normal vector) with the value of Qa _n+1 /Qb _n+1 . In addition, the normal vector comparison unit 29 is configured to perform a similar comparison for other normal vectors as well. For example, the value of Pa _n /Pb _n is compared with the value of Qa _n /Qb _n , and the value of Pa _n+2 /Pb _n+2 and the value of Qa _n+2 /Qb _n+2 are compared. are meant to be compared.

As a result of the above comparison, the value of the normal vector VP _n+1 of the point P _n+1 shown in FIG. 5 (Pa _n+1 /Pb _n+1 ) and the value of the normal vector VQ _n+1 of the point Q _n+1 The values (Qa _n+1 /Qb _n+1 ) coincide with each other. That is, the value of the normal vector VP _n+1 of the point P _n+1 (Pa _n+1 /Pb _n+1 ) and the value of the normal vector VQ _n+1 of the point Q _n+1 (Qa _n+1 /Qb _n+1 ) is smaller than a predetermined threshold value.

Meanwhile, the value of the normal vector VP _n+2 of the point P _n+2 (Pa _n+2 /Pb _n+2 ) and the value of the normal vector VQ _n+2 of the point Q _n+2 (Q _an+2 /Qb _n+2 ) are different. That is, the difference between the value of the normal vector VP _n+2 (Pa _n+2 /Pb _n+2 ) and the value of the normal vector VQ _n+2 of the point Q _n+2 (Qa _n+2 /Qb _n+2 ) It is larger than a predetermined threshold value.

To make a similar comparison, the value of the normal vector VP _n+3 is different from the value of the normal vector VQ _n+3 , and the value of the normal vector VP _n+4 is different from the value of the normal vector VQ _n+4 . In addition, the value of the normal vector VP _n+5 and the value of the normal vector VQ _n+5 are different from each other, and the value of the normal vector VP _n+6 and the value of the normal vector VQ _n+6 coincide with each other.

Then, the tool shape determination unit 31 determines that the shape of the tool 12 is changing at points P _n+2 (point Q _n+2 ) to points P _n+5 (point Q _n+5 ). are meant to make judgments.

Next, detection of the wear amount of the tool 12 will be described.

As described above, the first plurality of normal vectors acquired by the normal vector acquisition unit 27 are normal vectors before use of the tool 12 . In addition, the device 1 includes an edge shape acquisition unit 33 and a tool shape change amount acquisition unit 35 .

The edge shape acquisition unit 33 is configured to obtain an edge 13 of the tool 12 by photographing the tool 12 with the camera 22 after the tool 12 is used. In addition, as described above, the normal vector acquisition unit 27 uses the plurality of points on the edge 13 of the tool 12 acquired by the edge shape acquisition unit 33 and the edge 13 to obtain a normal vector. is meant to be saved.

The tool shape change amount acquisition unit 35 uses the first plurality of normal vectors obtained by the normal vector acquisition unit 27 and the edge 13 of the tool 12 obtained by the edge shape acquisition unit 33, The amount of change in the shape of the tool 12 after use with respect to the shape of the tool 12 before is determined. Further, as the amount of change in the shape of the tool 12, the amount of wear of the tool 12, the amount of defect in the tool 12, and the like are exemplified.

Here, the calculation of the change amount of the shape of the tool 12 by the tool shape change amount acquisition unit 35 will be described in more detail with reference to FIG. 7 .

A method for determining the amount of change in the shape of the tool 12 will be described taking point P _n+2 as an example. First, the normal vector VP _n+ 2 of the point P _n+ 2 is obtained. Subsequently, a straight line passing through the point P _n+2 and having the slope coincident with the normal vector VP _{n +2} (the equation of the straight line including the normal vector VP n+2 starting at the point P _n+2 ) is obtained.

Then, the intersection Q _m+2 of the straight line and the edge 13a is obtained, and the length of the line segment L _n+2 connecting the point P _n+2 and the intersection Q _m+2 is obtained. The value of the length of this line segment L _n+2 becomes the change amount of the shape of the tool 12 in the part of the point P _n+2 . Similarly, the amount of change in the shape of the tool 12 is obtained for other points such as the point P _n+3 .

Next, the operation of the device 1 for detecting the shape of a tool will be described with reference to FIG. 8 .

As an initial state, the tool 12 is rotating, and as shown in FIG. 2 , the shape of the tool 12 can be measured by the device 1 .

In the initial state, the tool 12 before use is photographed by the camera 22 under the control of the controller 20 (the control unit 25) (S1), and the normal vector acquisition unit 27 photographs in step S1. A normal vector of one tool 12 is obtained (S3).

Subsequently, predetermined cutting is performed on the work 14 using the tool 12 (S5), and the tool 12 after being used in step S55 is photographed with the camera 22 (S7).

Subsequently, the edge 13 of the tool 12 photographed in step S7 is obtained by the edge shape acquisition unit 33, and the normal vector acquisition unit 27 obtains the edge 12 of the tool 12 photographed in step S7. A normal vector is obtained (S9).

Subsequently, the normal vector of the tool 12 obtained in step S3 and the normal vector of the tool 12 obtained in step S9 are compared by the normal vector comparator 29 (S11). Subsequently, based on the comparison result in step S11, it is determined by the tool shape determination unit 31 whether or not the shape of the tool 12 has changed (S13).

Subsequently, the tool shape change amount acquisition unit 35 obtains the shape change amount of the tool 12 based on the normal vector of the tool 12 obtained in step S3 and the edge of the tool 12 obtained in step S9 (S15) .

In the apparatus 1 for detecting the shape of a tool, the normal vectors are obtained from a plurality of points on the edge 13 of the tool 12 by the normal vector acquisition unit 27, and the normal vectors by the normal vector comparison unit 29 , the first plurality of normal vectors and the second plurality of normal vectors are compared. And, when the value of the first plurality of normal vectors and the value of the second plurality of normal vectors differ from a predetermined threshold value, the tool shape determination unit 31 determines that the shape of the tool 12 is changing. have.

In this way, it is possible to measure the shape of the tool 12 whose shape is unknown, and to detect an abnormality in the shape of the tool 12. In addition, by comparing the normal vectors, it is determined whether or not the shape of the tool 12 before and after use has changed, so the shape of the tool 12 can be measured simply by photographing the tool 12 before and after use. Compared to the case of comparison, the change in the shape of the tool 12 can be accurately detected.

By the way, the above-described device 1 is a device for detecting the shape of a tool installed on the main shaft of a machine tool, a camera for photographing the shape of the tool, and a camera for photographing the tool before use of the tool to detect the shape of the tool. a normal vector acquisition unit that obtains a normal vector at a plurality of points on the edge of the tool; an edge shape acquisition unit that obtains the edge of the tool by photographing the tool with the camera after the tool is used; and the normal vector acquisition unit It may be understood as a device having a tool shape change amount acquisition unit that obtains the amount of change in the shape of the tool after use with respect to the shape of the tool before use, using the normal vector obtained in and the edge of the tool obtained by the edge shape acquisition unit. .

In this device 1, the normal vector is obtained from a plurality of points on the edge 13 of the tool 12 before use in the normal vector acquisition unit 27, and the edge shape acquisition unit 33 obtains the tool after use ( The edge 13a of 12) is obtained. Then, using the normal vector obtained by the normal vector acquisition unit 27 and the edge 13a of the tool 12 obtained by the edge shape acquisition unit 33, in the tool shape variation acquisition unit 35, the tool before use It is intended to obtain the amount of change in the shape of the tool 12 after use with respect to the shape of (12).

In this way, it is possible to accurately detect the part of the tool 12 where chipping, wear, and abrasion due to use have occurred.

In addition, the above-described device 1 is a device for detecting the shape of a tool installed on the main shaft of a machine tool, a camera for photographing the shape of the tool, and a camera for photographing the tool before use of the tool to detect the shape of the tool. an edge shape acquisition unit that obtains an edge of the tool, a normal vector acquisition unit that photographs the tool with the camera after use of the tool, and obtains a normal vector at a plurality of points on the edge of the tool, and the normal vector acquisition unit It may be understood as a device having a tool shape change amount acquisition unit that obtains the amount of change in the shape of the tool after use with respect to the shape of the tool before use, using the normal vector obtained in and the edge of the tool obtained by the edge shape acquisition unit. .

In addition, you may grasp the above description content as a method of detecting the shape of a tool.

That is, a method for detecting the shape of a tool mounted on a main shaft of a machine tool, comprising: a normal vector acquisition step of obtaining these normal vectors from a plurality of points on the edge of the tool captured by a camera that photographs the shape of the tool; A normal vector comparison step of comparing the first plurality of normal vectors acquired in the vector acquisition step with the second plurality of normal vectors acquired next in the normal vector acquisition step, and the result of the comparison in the normal vector comparison step, the first It may be understood as a method having a tool shape determination step of determining that the shape of the tool is changing when the values of the plurality of normal vectors and the values of the second plurality of normal vectors differ from a predetermined threshold value.

In addition, the first plurality of normal vectors obtained in the normal vector acquisition step are normal vectors before use of the tool, and after use of the tool, an edge shape obtained by taking a picture of the tool with the camera and obtaining an edge of the tool The amount of change in the shape of the tool after use relative to the shape of the tool before use, using the acquisition step, the first plurality of normal vectors obtained in the normal vector acquisition step, and the edge of the tool obtained in the edge shape acquisition step It may be understood as a method for detecting the shape of a tool described in claim 5 having a tool shape change amount acquisition step for obtaining .

Although several embodiments have been described, it is possible to make modifications or variations of the embodiments based on the above disclosure.

1: device
2: machine tool
11: Spindle
12: tool
13, 13a: edge of tool
22: camera
27: normal vector acquisition unit
29: normal vector comparison unit
31: tool shape determination unit
33: edge shape acquisition unit
35: tool shape variation acquisition unit

Claims (6)

A device for detecting the shape of a tool installed on the main axis of a machine tool,
A camera for photographing the shape;
a specific vector acquisition unit that obtains specific vectors from a plurality of points on the edge of the tool captured by the camera;
a specific vector comparing unit that compares a plurality of first specific vectors acquired at a first time point by the specific vector obtaining unit with a plurality of second specific vectors acquired at a second time point;
When the value of the first plurality of specific vectors and the value of the second plurality of specific vectors differ from a predetermined threshold value as a result of the comparison in the specific vector comparing unit, it is determined that the shape of the tool is changing. tool shape judgment
wherein the specific vector is a normal vector, a tangential vector, or a specific gradient vector inclined by a predetermined angle with respect to the normal vector. According to claim 1,
The first plurality of specific vectors acquired by the specific vector acquisition unit are specific vectors before use of the tool;
an edge shape acquiring unit for obtaining an edge of the tool by photographing the tool with the camera after the tool is used;
A tool shape for obtaining a change in the shape of the tool after use with respect to the shape of the tool before use using the first plurality of specific vectors obtained by the specific vector acquisition unit and the edge of the tool obtained by the edge shape acquisition unit change amount acquisition unit
device to have. A device for detecting the shape of a tool installed on the main axis of a machine tool,
A camera for photographing the shape of the tool;
a specific vector obtaining unit for obtaining a specific vector at a plurality of points on an edge of the tool by photographing the tool with the camera before using the tool;
an edge shape acquiring unit for obtaining an edge of the tool by photographing the tool with the camera after the tool is used;
A tool shape change amount acquisition unit that obtains a change amount of the shape of the tool after use with respect to the shape of the tool before use, using the specific vector obtained by the specific vector acquisition unit and the edge of the tool obtained by the edge shape acquisition unit;
wherein the specific vector is a normal vector, a tangential vector, or a specific gradient vector inclined by a predetermined angle with respect to the normal vector. A device for detecting the shape of a tool installed on the main axis of a machine tool,
A camera for photographing the shape of the tool;
an edge shape acquisition unit for obtaining an edge of the tool by photographing the tool with the camera before using the tool;
a specific vector obtaining unit for obtaining a specific vector at a plurality of points on an edge of the tool by photographing the tool with the camera after the tool is used;
A tool shape change amount acquisition unit that obtains a change amount of the shape of the tool after use with respect to the shape of the tool before use, using the specific vector obtained by the specific vector acquisition unit and the edge of the tool obtained by the edge shape acquisition unit;
wherein the specific vector is a normal vector, a tangential vector, or a specific gradient vector inclined by a predetermined angle with respect to the normal vector. A method for detecting the shape of a tool installed on a spindle of a machine tool,
A specific vector acquisition step of obtaining these specific vectors from a plurality of points on the edge of the tool captured by a camera that photographs the shape of the tool;
a specific vector comparison step of comparing the first plurality of specific vectors acquired in the specific vector acquisition step with the second plurality of specific vectors acquired next in the specific vector acquisition step;
As a result of the comparison in the specific vector comparison step, when the values of the first plurality of specific vectors and the values of the second plurality of specific vectors differ from a predetermined threshold value, it is determined that the shape of the tool is changing. Tool shape judgment step
wherein the specific vector is a normal vector, a tangent vector, or a specific gradient vector inclined by a predetermined angle with respect to the normal vector. According to claim 5,
The first plurality of specific vectors acquired in the specific vector acquiring step are specific vectors before use of the tool;
After using the tool, an edge shape acquisition step of obtaining an edge of the tool by photographing the tool with the camera;
A tool shape for obtaining a change in the shape of the tool after use with respect to the shape of the tool before use using the first plurality of specific vectors obtained in the specific vector acquisition step and the edge of the tool obtained in the edge shape acquisition step change amount acquisition step
how to have

Images