JP2023055276A - Tool tip measurement device and tool tip measurement method - Google Patents

Abstract

To provide the tip position and shape of a tool without creating a dummy workpiece with trial processing.SOLUTION: A tool tip measurement device 1 is arranged such that an imaging device 2 is arranged in any of the left and right sides with a tool G of a machine tool held therebetween, and reflection means is arranged on the other side becoming the position opposed to the imaging device 2. Illumination means irradiates the tool G with parallel light, and the light is regression-reflected by the reflection means. The imaging device 2 images the tip of the tool G and acquires the position and shape thereof. The imaging device 2 images the positions and shapes of the tool G being stopped and the tool G being operated. An image processing unit 322 of a terminal 3 binarizes the images of the tool G being stopped and the tool G being operated captured by the imaging device 2. The image processing unit 322 extracts a contour of the tool G in the operation from the binarized image of the tool G being operated and compares it with the binarized image of the tool G being stopped. A measurement unit 321 of the terminal 3 compares the shape of the tool G being stopped with the contour of the tool G in the operation to measure a difference.SELECTED DRAWING: Figure 1

Description

Patent Law Article 30, Paragraph 2 application filed Between April 21, 2021 and August 31, 2021, Nagamine Seisakusho Co., Ltd. (1725-26 Kishigami, Mannou-cho, Nakatado-gun, Kagawa) On August 31, 2021, sold to Nagamine Seisakusho Co., Ltd. via Nikko Kizai Co., Ltd. (8-2-3 Tanimachi, Chuo-ku, Osaka-shi, Osaka)

The present invention relates to a device for measuring the position and shape of the tip of a tool attached to a machine tool for processing metal, such as a surface grinder, a milling machine, and a machining center. It relates to a device for measuring the contour of

In metal processing, when manufacturing a product by grinding or cutting using a machine tool, what position the tool used touches the object to be processed (workpiece) and the result of processing In general, trial machining is performed using the tool and a dummy work in order to confirm what kind of machining will be performed.
Such trial machining is performed to confirm changes in the tool that occur during machining. For example, in the case of grinding, wear of the grinding surface due to grinding work and elongation due to thermal expansion of the rotating shaft occur, so the grinding surface changes during grinding, and the dimensions of the workpiece change accordingly.
For this reason, trial machining is performed, the shape of the dummy work subjected to the trial machining is measured, and the dimensions of machining to be applied to the workpiece are determined from the measurement results in consideration of changes in the tool during operation. The determined dimensions can be reflected in the position of the tool when machining the workpiece, the depth and width of grinding in machining, and the like, thereby improving the machining accuracy of the workpiece and reducing the occurrence of defective products.
Here, the dummy work is measured by removing the dummy work from the machine tool and using a device separate from the machine tool, and the machining dimensions of the work are determined from the measurement result.
In this way, the creation of the dummy work is a necessary procedure for determining the machining dimensions of the work in the machining of the work.

However, when creating a dummy workpiece through trial machining, it must be created using the same machining equipment, machining tools, workpiece, and various machining conditions such as tool rotation speed and feed rate as those used in product production. The numerical values necessary for indexing the machining dimensions for the workpiece cannot be obtained. If the material for the dummy work is inexpensive, it is possible to create the dummy work by such a method, but if the object to be actually manufactured is expensive, the cost will be increased accordingly.
In addition, when the type of tool, for example, the tool used for processing is a grindstone, the grindstone used when the accuracy required for the product is in units of μ has a fine grain size and a soft bond, Since the grindstone wears out so much, it may be necessary to replace the grindstone just by processing a dummy workpiece. In addition, the tool may be damaged during the trial machining, and the creation of the dummy work may require the cost of the tool as well as the cost of the work.
Above all, creating the dummy work consumes human labor and time for workers to process the dummy work and measure it.

For example, Patent Document 1 has been disclosed as a device for measuring the position and shape of a grindstone in a machine tool, particularly a grinder.
The technique described in Patent Document 1 is a grinding wheel shape measuring method, a measuring device, and the measuring method of a grinder capable of improving processing accuracy and processing efficiency by automatically measuring and correcting the shape of the grinding wheel. It provides a processing method using. The grindstone shape measuring method for a grinder described in Patent Document 1 is a grinder that performs grinding by relatively moving a table on which a workpiece is placed and fixed with respect to a rotating grindstone, wherein the table The grindstone is brought into contact with a reference piece of known shape provided above from a plurality of predetermined directions, and the shape of the tip corner portion of the grindstone is measured based on the obtained position data and shape data of the reference piece. and

However, in the technique described in Patent Document 1, it is necessary to actually process a dummy work, and it is not possible to expect a reduction in labor and cost for processing the dummy work. Therefore, it is not possible to grasp the shape of the entire tip of the grindstone during rotation.

JP-A-09-029628

The present invention captures the position of the tip of a tool attached to a metal processing machine tool such as a surface grinder, a milling machine, and a machining center, as well as the stopped and operating tools. To calculate the contour of a tool during operation including deflection, measure the shape of the tool, and provide the tip position and shape of the tool without creating a dummy work by trial machining.

According to the first aspect of the invention, there is provided a device for recognizing the position and shape of the tip of a machine tool having a tool for grinding or cutting a workpiece, wherein the tip shape of the tool is photographed. a first lighting means for illuminating the tool to be photographed by the imaging means; and a first lighting means for illuminating the tool photographed by the imaging means. second illumination means for illuminating the tool; measurement means for measuring the position of the tip of the tool and the shape of the tip of the tool from the image captured by the imaging means; and the image captured by the imaging means. The image processing means comprises a camera and a lens, and the image processing means binarizes the image of the tool during operation captured by the image capturing means. The contour of the tool during operation is extracted, the measuring means acquires reference coordinates that serve as a reference for measuring the tip position of the tool, and the contour of the tool extracted by the image processing means is measured. A tool tip measuring device characterized by:
In the invention according to claim 2, the light emitted from the first illumination means and the second illumination means is parallel light in which all light rays are parallel. 2. Provide the tool tip measuring device according to .
In the invention according to claim 3, one of the first illumination means and the second illumination means has a light source, and the other illumination means without a light source is illuminated by the illumination means having the light source. The tool tip measuring device according to any one of claims 1 to 2, characterized in that the tool is illuminated by reflecting the illuminated light.
In the invention according to claim 4, the first illumination means has a light source, and the second illumination means illuminates the tool by reflecting the light illuminated by the first illumination means. The tool tip measuring device according to claim 3 is provided, characterized by:
According to a fifth aspect of the invention, there is provided the tool tip measuring apparatus according to any one of the first to fourth aspects, further comprising a gauge having a predetermined shape for acquiring the reference coordinates. A tool tip measuring device characterized by:
According to a sixth aspect of the present invention, there is provided a method for measuring the position and shape of the tip of a tool by using any one of the tool tip measuring devices according to the first to fifth aspects.

According to the invention of claim 1, there is provided a machine tool having a tool for grinding or cutting a workpiece, wherein the device recognizes the position and shape of the tip of the tool, wherein the shape of the tip of the tool is and a first lighting means for illuminating the tool photographed by the imaging means, arranged in a position opposite to the first lighting means, and the imaging means is provided in parallel with the imaging means. second illumination means for illuminating the tool to be photographed; measurement means for measuring the position of the tip of the tool and the shape of the tip of the tool from the image photographed by the imaging means; and imaging by the imaging means. and image processing means for processing an image to be processed, wherein the imaging means comprises a camera and a lens, and the image processing means binarizes the image of the tool during operation captured by the imaging means. and extracts the contour of the tool during operation, and the measuring means acquires reference coordinates serving as a reference for measuring the tip position of the tool, and measures the contour of the tool extracted by the image processing means. Therefore, when illuminating the tool to be measured, the diffraction of light generated around the tool can be reduced, the contour of the tool can be photographed more clearly, and the tip of the tool can be photographed more clearly. position and shape can be measured more precisely.
According to the second aspect of the invention, the light emitted from the first illumination device and the second illumination device is parallel light in which all light rays are parallel. By reducing the diffuse reflection of the tool, the outline of the tool can be photographed more clearly.
According to the third aspect of the invention, one of the first illumination means and the second illumination means has a light source, and the other illumination means without a light source is an illumination device having the light source. Since the tool is illuminated by reflecting the light illuminated by the means, it is possible to reduce the cost of manufacturing the tool tip measuring device by using only one illumination source.
According to the fourth aspect of the invention, the first illumination means has a light source, and the second illumination means reflects the light illuminated by the first illumination means to light the tool. Since the illumination is provided, it is easier to align the axes of the illumination and to facilitate the arrangement of the illumination means compared to the case where the second illumination means has a light source.
According to the invention of claim 5, the tool tip measuring apparatus according to any one of claims 1 to 4, further comprising a gauge having a predetermined shape for acquiring the reference coordinates. Therefore, it is possible to easily set the reference coordinates.
According to the invention of claim 6, the position and shape of the tip of the tool are measured by using any one of the tool tip measuring devices of claims 1 to 5. The position and shape of the tip of the tool can be measured more precisely.

It is a figure which shows the structure of the tool tip measuring device 1 in this embodiment. It is a figure which shows the components which comprise the imaging device 2 in this embodiment. It is a figure which shows the shape of the gauge 26 in this embodiment. FIG. 4 is a cross-sectional view showing an example of arrangement of reflecting means 22, gauge 26, lens 211, body 24, and holder 25 with respect to the tool in this embodiment. It is a figure which shows an example of a structure of the screen which image|photographs and measures in this embodiment. FIG. 5 is a diagram showing the difference between the shape of the tool when it is stopped and the shape of the tool when it is in operation in this embodiment.

Preferred embodiments of the tool tip measuring device and the tool tip measuring method of the present invention will be described in detail below with reference to FIGS. 1 to 6. FIG.
(1) Outline of Embodiment A tool tip measuring device 1 is attached to a table of a machine tool. The tool tip measuring device 1 has an imaging device 2 on either side of the tool of the machine tool, and a reflecting means 22 on the other side facing the imaging device 2 . In photographing, the illumination means 22 provided together with the photographing means 21 irradiates the tool with parallel light, and the parallel light irradiated on the tool is retroreflected in the direction of the photographing means 21 by the reflecting means 22 .
The imaging device 2 photographs the tip of the tool to be measured, and obtains its position and shape. What is imaged by the imaging device 2 is the position and shape of a stopped tool and an operating tool.
The image processing unit 322 of the terminal 3 binarizes the images of the stopped tool and the operating tool captured by the imaging device 2 . The image processing unit 322 extracts the contour of the tool in operation from the binarized image of the tool in operation, and compares it with the binarized image of the tool in operation.
The measuring unit 321 of the terminal 3 compares the shape of the stopped tool with the contour of the tool during operation, and measures the difference.

(2) Details of Embodiment FIG. 1 shows a configuration diagram of a tool tip measuring device 1 according to the present embodiment.
The tool tip measuring device 1 includes an imaging device 2 arranged on a table of a machine tool to photograph a tool attached to the machine tool, and measures the position and shape of the tool photographed from the image photographed by the imaging device 2. terminal 3;
The imaging device 2 and the terminal 3 are connected to each other by wired communication.

2A and 2B are diagrams showing components constituting the imaging device 2. FIG.
The imaging device 2 is composed of photographing means 21 , reflecting means 22 , protective cover 23 , body 24 and holder 25 .
The imaging device 2 retroreflects the parallel light from the illumination 212 by the reflecting means 22, so that the light diffraction does not occur in the vicinity of the tool, and the shape of the tool can be imaged more clearly.
The photographing means 21 is composed of a lens 211 , a lighting 212 and a camera 213 .
The lens 211 is an optical lens, and in particular, a telecentric optical lens with no angle of view is suitable. Various magnifications of the lens can be selected, and the lens can be exchanged according to the tool to be measured by the tool tip measuring device 1 .
The illumination by the illumination 212 is parallel light. By irradiating with parallel light, the outline of the tool can be emphasized. Parallel light can be obtained by irradiating with coaxial epi-illumination.
In this embodiment, the lens 211 is a telecentric optical lens, so the illumination 212 is coaxial epi-illumination using a telecentric lens. The lens 211 uses a telecentric lens capable of coaxial epi-illumination.
A camera 213 is a CCD camera, a CMOS camera, or the like.

The reflecting means 22 is arranged perpendicular to the optical axis of the lens 211 on the surface facing the photographing means 21 and reflects the irradiation from the illumination 212 .
The reflecting means 22 may be a metal-based mirror having a degree of parallelism that reflects the parallel light emitted from the illumination 212 through the lens 211 as parallel light. A general optical mirror may be used, and in the present embodiment, a SUS440C mirror-finished mirror is used. The presence or absence of coating on the super-mirror-finished surface does not matter.

The protective cover 23 is a cover for protecting the photographing means 21 from dirt. Grinding fluid, cutting oil, coolant, and the like splatter on the table of the machine tool when the machine tool is operated and the work is processed by the tool.
The protective cover 23 is formed in a U-shaped dome shape, has a length covering from the end of the lens 211 to part of the cable connected to the camera 213 , and is attached and fixed to the holder 25 .
Both side surfaces of the protective cover 23 are inclined from the end in contact with the holder 25 toward the camera 213 side, and the width of the both side surfaces in the vertical direction gradually narrows. When routing the cable connected to the camera 213, it is possible to reduce the difficulty in routing the cable due to contact between the protective cover 23 and the cable.
Although the protective cover 23 is made of acrylic in this embodiment, it may be made of other materials.

The body 24 is a base for integrating the photographing means 21 and the reflecting means 22 . The photographing means 21 is arranged at one end of the body 24 in the longitudinal direction, and the reflecting means 22 is arranged at the opposite end thereof.
One end of the body 24 to which the photographing means 21 is attached has a substantially semi-elliptical concave portion. The recess is part of a hole for arranging a cable connected to the illumination port of the lens 211, and forms one hole together with the holder 25, which will be described later. The concave portion has a substantially semi-elliptical shape, and the hole formed together with the holder 25 is formed larger than the diameter of the illumination port of the lens 211 . This is to provide play for ensuring the distance (work distance) from the tip of the lens to the object when the lens 211 is replaced with another lens having a different magnification.
The length of the body 24 in the longitudinal direction is such that the tool can be placed between the photographing means 21 and the reflecting means 22, and at least the length is such that the work distance from the lens 211 to the tool can be secured. is necessary.
The distance from the tool to the reflecting means 22 may be a distance at which the parallel light reflected by the reflecting means 22 reaches the tool. In other words, the distance from the tool to the reflecting means 22 is such that the parallel light emitted from the reflecting means 22 can cancel the shadow formed by the collimated light emitted from the illumination 212 encountering the tool and being diffracted. I wish I had.

The width of the upper surface of the body 24 in the lateral direction is approximately determined by the width of the photographing means 21 . In other words, any width may be used as long as the lens 211 can be held stably. In this embodiment, the length of the upper surface of the body 24 in the lateral direction is 40 mm.
The body 24 is preferably made of magnetic material. The imaging device 2 is placed on a table of a machine tool and used, but it is preferable that the imaging device 2 is fixed on the table during use, and most of the table of the machine tool is an electromagnetic chuck. Therefore, if the body 24 is made of a magnetic material, the imaging device 2 can be fixed to the table of the machine tool with a magnetic chuck.

Holder 25 supports lens 211 . The holder 25 consists of a holder 25a and a holder 25b, and has a structure in which the lens 211 is sandwiched from above and below.
The diameter of the hole formed by the holders 25a and 25b is determined by the diameter of the lens 211 at the position sandwiched by the holders 25a and 25b.
Holder 25b forms a hole with body 24 as described above.
Also, the holder 25b has a hole on its rear surface for passing a cable connected to the illumination port of the lens 211. As shown in FIG.

The cage 26 is a gauge used when setting the reference coordinates of the tool tip measuring device 1 .
The reference coordinates virtually set the dimensions of the dummy work.
When creating a dummy work, the dimensions of the dummy work are required. This is because the position and shape of the tip of the tool can be confirmed by machining an object whose dimensions are known in the machine tool. Since the tool tip measuring apparatus 1 does not machine a dummy work, the gauge 26 is used to virtually set the dimensions of the work in creating a dummy work.

FIG. 3 is a perspective view showing the shape of the cage 26. As shown in FIG.
The gauge 26 has sharp edges SE1, SE2, SE3 which are straight lines indicating three directions for setting reference coordinates. The sharp edges SE1, SE2, and SE3 respectively correspond to the machine coordinate Z-axis (vertical direction), Y-axis (front-rear direction, depth), and X-axis (horizontal direction) of the machine tool. In the terminal 3, which will be described later, the crosshair cursor is aligned with the intersections with the sharp edges SE1, SE2, and SE3 of the gauge 26, and the positions are stored as reference coordinates.
The gauge 26 is formed so that the intersection of the sharp edge SE1 and the sharp edge SE2 is at the same position as the center of the lens 211 when the photographing means 21 is attached to the body 24 .
The gauge 26 is attached to the body 24 by fitting the concave portion of the bottom surface into the body 24 .
The concave portion of the bottom surface of the gauge 26 is formed so that there is no gap between the gauge 26 and the body 24 when the gauge 26 is fitted into the body 24 . As a result, the gauge 26 can be arranged with the sharp edge SE1 parallel to the lens 211 and the sharp edge SE3 perpendicular thereto.

FIG. 4 is a cross-sectional view showing an example of arrangement of the reflecting means 22, gauge 26, lens 211, body 24, and holder 25 with respect to the tool (grinding wheel G in the surface grinder) in this embodiment.
The lens 211 used in this embodiment has a lens outer diameter of Φ25, a portion supported by the holder 25 has a diameter of Φ22, an illumination port has a diameter of Φ8, and a working distance is 65 mm.
The length of the body 24 in the longitudinal direction includes, in addition to the work distance, which is the distance to the tip of the grindstone G, the distance from the grindstone G to the reflecting means 22, and the length from the tip of the lens 211 to a portion of the illumination port. determined based on
In this embodiment, the length of the body 24 in the longitudinal direction is 162 mm, the work distance from the lens 211 to the grinding wheel G is 65 mm, the distance from the grinding wheel G to the reflecting means 22 is 65 mm, and the distance from the tip of the lens 211 to the illumination port is 65 mm. The length to part is approximately 33 mm.

The lens 211 in this embodiment employs a lens with a working distance of approximately 65 mm. This is because the uniform work distance makes it easier to align the cage 26 and the grindstone G, thereby improving work efficiency.
As described above, the hole formed together with the holder 25b and the body 24 is configured to be larger than the diameter of the illumination port, the shape of the hole is substantially oval, and there is play, so the position of the lens 211 is within the play. , the body 24 can be moved in the longitudinal direction. For this reason, the work distance is not limited to 65 mm, and can be selected as appropriate within a range that allows play.
Thus, in this embodiment, the work distance is limited in order to improve the work efficiency, and the length of the body 24 in the longitudinal direction is designated based on the length of the work distance. Other means of length determination may be used.
For example, the body 24 may be of a sliding type, the longitudinal length of which is variable, and a memory indicating the work distance may be engraved on the body 24 to indicate the position where the gauge 26 is arranged.

The lens 211 is arranged so that the center of the lens 211 is positioned 20 mm from the upper surface of the body 24 . The distance from the upper surface of the body 24 to the center of the lens 211 ensures that the lens 211 does not come into contact with the body 24 even when the lens to be used is changed.
The height of the bottom surface of the gauge 26 from the recess is determined according to the center of the lens 211 . In this embodiment, it is 20 mm. Sharp edge SE2 is 20 mm from the intersection with SE1, and SE3 is 25 mm.
In this embodiment, since the center of the lens 211 is 20 mm from the upper surface of the body 24, the height of the reflecting means 22 is set to 40 mm. The width of the reflecting means 22 is adapted to the width of the body 24 .
The size of the reflecting means 22 is determined by the configuration of the photographing means 21 .

Next, the height of the body 24 will be explained.
As described above, in determining the machining dimensions of the machine tool, the virtual dimension is determined by the gauge 26. In the direction of the sharp edge SE1, not only the height of the gauge 26 but also the height of the body 24 The added height becomes the value of the Z coordinate of the reference coordinates, which will be described later.
This is because the bottom surface of the workpiece is placed on the table of the machine tool, and the bottom surface of the body 24 of the tool tip measuring device 1 is placed on the table.
Therefore, it is preferable that the height of the body 24 is a well-defined numerical value in order to avoid complicated calculations. In this embodiment, the height of the body 24 is 25 mm, the height of the gauge 26 is 20 mm, and the value of the Z coordinate of the reference coordinates is 45 mm.
As for the height of the body 24, as a maximum value, the height from the bottom surface of the body 24 to the intersection with the sharp edges SE1, SE2, and SE2 of the gauge 26 should be within the range of the Z coordinate of the machine tool, and as a minimum value, should be high enough to accommodate the illumination port of the lens 211 and the cable connected thereto in the hole formed by the body 24 and the holder 25 .

Next, the configuration of the terminal 3 will be explained.
The terminal 3 includes a control unit 31, and is connected to a storage unit 32, a communication control unit 33, a touch panel 34, a display unit 35, and other devices via a bus line such as a data bus.
The control unit 31 includes a CPU 311 , a ROM 312 and a RAM 313 .
The CPU 311 controls the device and each part according to the program and performs calculations.
The ROM 312 is a read-only memory in which various programs and data for the CPU 311 to perform various controls and calculations are stored in advance.
A RAM 313 is a random access memory used by the CPU 311 as a working memory. In the RAM 313, it is possible to secure various areas for performing various processes such as calculations for measurement according to this embodiment.

The storage unit 32 is composed of a writable storage medium, and a hard disk is mainly used. The storage unit 32 has a measuring unit 321 and an image processing unit 322 .
The measuring unit 321 compares the shape of the stopped tool with the contour of the tool during operation to measure the difference, and also performs calculations such as measuring the distance at the input position according to the input from the touch panel 34. conduct.
The image processing unit 322 binarizes the images of the stopped tool and the operating tool captured by the imaging device 2 .
The image processing unit 322 extracts the contour of the tool in operation from the image of the tool in operation, and performs image processing such as comparison with the image of the tool in operation.
The communication control unit 33 is a control device for connecting the terminal 3 and various external electronic devices such as the imaging device 2, machine tools, and other personal computers via a communication network.

The touch panel 34 is an input device that is placed over the front surface of the display unit 35 and receives input from a touch pen or a user's finger. The touch panel 34 is composed of, for example, a pressure-sensitive touch sensor panel, detects pressure of a touch pen or the like, and detects a touch operation such as contact and its position (touch position). The touch panel 34 may, for example, sense and detect the touch of a user's finger or the like from changes in capacitance. In addition to the touch panel, the input device may be a keyboard, a mouse, or the like.
The display unit 35 is, for example, a liquid crystal display or the like, and it is desirable to use a full high-definition panel or higher. The display unit 35 displays an image captured by the imaging device 2 , the calculation result of the measurement unit 321 , measurement buttons necessary for inputting a measurement instruction by a worker or the like touching the touch panel 34 , and the like.

Next, how to use the embodiment configured as described above will be described.
In this embodiment, the machine tool is a horizontal axis angle table type surface grinder, and the tool used for processing is a grindstone for traverse grinding.
When measuring the position and shape of the tip of the grindstone, initialization settings are performed to acquire the reference coordinates, and then the tip of the tool is measured.

First, the initialization setting will be explained.
The operator sets the imaging device 2 of the tool tip measuring device 1 on the table of the machine tool M and fits the gauge 26 into the body 24 .
The operator activates the terminal 3 of the tool tip measuring device 1 .
If the terminal 3 is not a dedicated terminal but a personal computer or the like, an application installed in the terminal 3 in advance for measuring the tip position and shape of the tool is activated. The application may be installed on the terminal 3 or may be provided in the cloud.
The control section 31 of the terminal 3 displays the measurement screen on the display section 35 .
The measurement screen includes a frame F1 for displaying an image captured by the imaging means 21 and an image of the measurement result, and a frame F2 for displaying settings of items necessary for measurement, buttons for performing measurement, and the like. .

The control unit 31 activates the imaging device 2 .
The operator touches the “lighting” button displayed on the measurement screen of the display unit 35 .
The control unit 31 irradiates from the illumination 212 of the imaging device 2 .
The operator touches the “capture” button displayed on the measurement screen of the display unit 35 .
The control unit 31 displays the image acquired from the imaging device 2 in the frame F1 displayed on the display unit 35, and displays a cross-shaped cursor on the image.
The operator checks the state of the gauge 26 displayed in the frame F1 of the display unit 35 and adjusts the position of the gauge 26 so that the image of the gauge 26 captured by the imaging device 2 is in focus.
Subsequently, the operator operates the touch panel 34 to move the cross cursor displayed in the frame F1 of the display unit 35 to the sharp edges SE1, SE2, and SE3 of the gauge 26 displayed in the frame F1 of the display unit 35. Move to intersection.
The crosshair cursor is used to obtain the coordinates of the intersection point of the crosshair, the horizontal direction of the crosshair cursor represents the Y-axis coordinates, and the sharp edge SE2 of the gauge 26 corresponds to the Y-coordinate. The vertical direction of the cross cursor represents the Z-axis coordinates, and the sharp edge SE1 of the gauge 26 corresponds to the Z-coordinates.

The operator touches the “reference setting” button displayed on the measurement screen of the display unit 35 .
The control unit 31 acquires the coordinates of the intersection point of the cross cursor displayed in the frame F1 of the display unit 35, and displays the Y coordinate and Z coordinate values on the measurement screen. In this embodiment, the Z coordinate is 45 due to the height of the body 24 and the height of the cage 26, and the Y coordinate is 20 due to the sharp edge SE2 of the gauge 26. FIG.
When the gauge 26 is not used to acquire the reference locus coordinates, the operator can place the crosshair cursor on any position and set the coordinates at which the crosshair cursor is displayed as the reference coordinates.

The operator touches the “save” button displayed on the measurement screen of the display unit 35 .
The control unit 31 acquires the coordinates of the intersection of the cross of the cross cursor displayed in the frame F1 of the display unit 35, and saves the values of the Y coordinate and the Z coordinate.
With the above operations, the initialization setting is completed.

Next, the tip position and shape of the tool are measured.
The operator sets the imaging device 2 of the tool tip measuring device 1 on the table of the machine tool M. As shown in FIG.
The operator activates the terminal 3 of the tool tip measuring device 1 .
The control section 31 of the terminal 3 displays the measurement screen on the display section 35 .
The control unit 31 activates the imaging device 2 .
The operator touches the “lighting” button displayed on the measurement screen of the display unit 35 .
The control unit 31 irradiates from the illumination 212 of the imaging device 2 .
The operator touches the “capture” button displayed on the measurement screen of the display unit 35 .
The control unit 31 displays the image acquired from the imaging device 2 in the frame F1 of the measurement screen displayed on the display unit 35 .

The operator touches the “reference line” button displayed on the measurement screen of the display unit 35 .
The control unit 31 displays a cross-shaped cursor on the reference coordinates (Y coordinate, Z coordinate) saved at the time of initialization on the image acquired from the imaging device 2 displayed in the frame F1.
The operator checks the state of the grindstone G displayed in the frame F1 of the display unit 35, and adjusts the position of the grindstone G so that the image of the grindstone G captured by the imaging device 2 is in focus.
The grindstone G is moved by an operator operating the machine tool M.
Subsequently, the operator adjusts the position of the grindstone G so that the tip of the grindstone G is at the position of the cross cursor displayed in the frame F1 of the display section 35 . As a result, the tip of the grindstone G is arranged on the reference coordinates.

The operator touches the “binarization” button displayed on the measurement screen of the display unit 35 .
The image processing unit 322 binarizes the image displayed in the frame F1 of the display unit 35, and the control unit 31 displays it in the frame F1.
The operator confirms the binarized state of the grindstone G displayed in the frame F1 of the display unit 35, and if necessary, operates the touch panel 34 to make the outline of the grindstone G clearer for measurement. Adjust the binarization threshold value displayed on the screen.
The image processing unit 322 binarizes the image according to the input binarization threshold, and the control unit 31 displays the binarized image in the frame F1.
The binarization threshold is set to a value that makes the binarized image as close as possible to the image before binarization. By making the binarized image similar to the image before binarization, the tool tip measuring apparatus 1 can acquire a more accurate position and shape of the tool.
Similarly, when the contour of the grindstone G becomes clearer by changing the "illumination value" that indicates the intensity value of the brightness of the illumination, the operator operates the touch panel 34 to display the measurement screen. Adjust the lighting value displayed in the .

Subsequently, the whetstone G in a stopped state and the whetstone G in a rotating state are photographed, and the position and shape of the whetstone G are obtained.
FIG. 5 is a diagram showing an example of the configuration of a measurement screen for photographing and measurement in this embodiment.
An image captured by the imaging device 2 and an image processed by the image processing unit 322 are displayed in the frame F1.
In the frame F2, "Stop" and "Rotate" buttons for photographing when the grindstone G is stopped or rotated, "Confirm" button for displaying the image photographed by the "Rotate" button, and "Stop" and "Rotate" buttons for A "Difference" button that displays the difference between the captured images is displayed.
Also displayed are various buttons for performing measurement at arbitrary positions on the image processed by the image processing unit 322 displayed in the frame F1. Various buttons include "R measurement", "move", and "delete" buttons for measuring the radius of the tip of the grindstone G, a "distance" button for measuring the distance between two points, and a "measure the distance from the reference coordinates". "Reference distance" and "Median distance" buttons for measuring the distance of the grindstone G from the reference coordinates in the Z coordinate direction are displayed.

FIG. 6 is a diagram showing the process of acquiring the difference between the shape of the tool when it is stopped and the shape of the tool when it is in operation in this embodiment.
In FIG. 6A , when the “Capture” button on the measurement screen of the display unit 35 is touched, the control unit 31 transfers the image captured by the imaging device 2 to the frame F1 of the measurement screen displayed on the display unit 35 . It shows how it is displayed.
The operator touches the “stop” button displayed on the measurement screen of the display unit 35 .
The control unit 31 captures an image of the grindstone G in a stopped state using the imaging device 2 , and the image processing unit 322 saves a binarized image of the grindstone G in a stopped state as an image A.

Subsequently, the operator operates the machine tool M to rotate the grindstone G, and touches the “rotation” button displayed on the measurement screen of the display unit 35 .
The control unit 31 takes a specified number of images of the rotating grindstone G from the imaging device 2 within a time specified in advance. In this embodiment, 100 images are taken per second.
The number of images to be captured (accumulated images) can be specified by inputting the desired number in the “accumulated images” displayed on the measurement screen of the display unit 35 . The operator can measure the shape of the tool more accurately by increasing or decreasing the accumulated number according to the rotation speed of the tool.
The image processing unit 322 binarizes and stores all captured images (image Bn).

FIG. 6(b) is an image Bn which is a binarized image obtained by photographing the rotating grindstone G when the "Confirm" button on the measurement screen of the display unit 35 is touched, and all the images included in the image Bn The image shows the shape of the grindstone G. FIG.
The operator touches the “confirm” button displayed on the measurement screen of the display unit 35 .
The control unit 31 displays an image (image C) obtained by extracting the outline of the rotating grindstone G from the binarized image Bn of the rotating grindstone G in the frame F1 of the measurement screen of the display unit 35 .
The operator confirms the image C displayed in the frame F1 of the display unit 35, and if necessary, changes the "number of images" and the photographing time, and performs "rotation", "stop", and "confirmation" operations again. I do.

FIG. 6C shows an image obtained by subtracting the image A from the image C, acquiring the difference between the image C and the image A, and expressing the difference in an image (image D).
The operator touches the “difference” button displayed on the measurement screen of the display unit 35 .
The image processing unit 322 subtracts the image A from the image C, acquires the difference between the image C and the image A, and acquires the image D representing the difference. The image D is displayed in the frame F1 of the measurement screen.
The operator confirms the image D displayed in the frame F<b>1 of the display unit 35 .
FIG. 6(d) is a diagram showing the measurement of the swing width during rotation of the grindstone G and the specification of the tip coordinates. The cross cursor indicates the reference coordinates, and the distance between the left and right arrows is the swing width.

Next, the types and methods of measurement provided by the tool tip measuring apparatus 1 will be described.
The tool tip measuring device 1 measures "R measurement", "distance", "reference distance", and "central line distance". These measurements are made on image C or image D. Hereinafter, the control unit 31 displays the image C in the frame F1 of the measurement screen displayed on the display unit 35. FIG.
"R measurement" is a function of measuring R at an arbitrary position.
When the operator wants to measure the R of the grindstone G, the operator touches “R measurement” on the measurement screen displayed on the display unit 35 .
Subsequently, the operator touches three points on the image C displayed in the frame F1 at positions where he wants to measure R.
The measurement unit 321 of the control unit 31 measures R from the approximate values of the three touched positions, and the control unit 31 displays a circle whose measured value is R at the touched position. is displayed in the display window W1.

"Distance" is a function that measures the distance between any two points.
The operator touches “distance” on the measurement screen displayed on the display unit 35 .
Subsequently, the operator touches the start point and end point of the position where the distance is to be measured on the image C displayed in the frame F1.
The measurement unit 321 of the control unit 31 measures the distance between the touched start point and the end point, the control unit 31 displays a straight line connecting the touched start point and the end point, and displays the measured distance value in the upper part of the frame F1. indicate.

The “reference distance” is the distance between the reference coordinates and the contour of the grindstone G indicated by the image C.
The operator touches the “reference distance” button displayed on the measurement screen of the display unit 35 .
Subsequently, the operator touches the position where the reference distance is to be measured on the contour of the grindstone G in the image C displayed in the frame F1.
The measurement unit 321 measures the distance between the reference coordinate Y and the touched position Y coordinate (reference distance Y) and the distance between the reference coordinate Z and the touched position Z coordinate (reference coordinate Z).
The control unit 31 displays the reference distance Y on the display window W2 of the display unit 35 and the reference distance Z on the display window W3.

The “median distance” is the distance (median distance Z) between the line that bisects the grinding wheel G shown in the image C in the Z direction and the reference coordinates Z.
The operator touches the “median distance” button displayed on the measurement screen of the display unit 35 .
The measurement unit 321 measures the distance between the reference coordinate Z and the line that bisects the grindstone G in the Z direction.
The control unit 31 displays the median distance Z in the display window W4.
When measuring these "R measurement", "distance", "reference distance", and "central distance", the measurement unit 321 calculates the distance based on the pixel values stored in the storage unit 32. FIG. Pixel values can be changed.

As described above, according to the tool tip measuring apparatus and the tool tip measuring method of the present embodiment, the imaging means causes the parallel light emitted from the lens side to be projected onto the lens by the reflecting means arranged at the position facing the lens. configured to retroreflect to the side. With this configuration, the parallel light irradiated from the lens side returns to the lens side without being diffracted around the tool, so that the outline of the tool to be measured placed between the lens and the reflecting means can be extracted more clearly. can do.
The tool tip measuring device acquires a plurality of images of the tip of the tool in a stopped state and a plurality of images of the tip of the tool in a rotating state, and acquires the shape of the rotating tool from the plurality of acquired images of the tool in a rotating state. In addition, the position and shape of the tool in the stopped state and the tool in rotation were compared, and the difference was measured. It is possible to determine machining dimensions that take into account the position and shape of the tool during operation without measuring .

Although the embodiments of the tool tip measuring device and the tool tip measuring method of the present invention have been described above, the present invention is not limited to the described embodiments, and various modifications can be made within the scope described in each claim. It is possible to do
For example, in the present embodiment, in view of the simplicity of the illumination axis alignment of the illumination 212 and the miniaturization of the tool tip measuring device 1, the illumination 212 is arranged on the lens 211 side, and the reflection means 22 is arranged, the positions of the illumination 212 and the reflecting means 22 may be interchanged. That is, the reflecting means 22 may be provided side by side with the lens 211 and the illumination 212 may be arranged at a position facing the lens 211 .
In this case, the illumination 212 is preferably illumination capable of emitting parallel light. Illumination using a telecentric lens can be adopted for known products.
In addition, in this embodiment, retroreflection by the reflecting means 22 is used to reduce the diffraction of light generated around the tool to be measured. Means may be arranged to reduce the diffraction of light.
If the tool to be measured is not a grindstone, or depending on the machining accuracy required for the workpiece, the light irradiated to the tool may not necessarily be parallel light. Illumination is not limited to illumination capable of emitting parallel light or parallel light, and illumination such as ring illumination and backlight can be selected as appropriate.

Reference Signs List 1 tool tip measuring device 2 imaging device 21 photographing means 211 lens 212 lighting 213 camera 22 reflecting means 23 protective cover 24 body 25 holder 26 gauge 3 terminal 31 control section 311 CPU
312 ROMs
313 RAM
32 storage unit 321 measurement unit 322 image processing unit 33 communication control unit 34 touch panel 35 display unit G grindstone F1 frame F2 frame W1 display window W2 display window W3 display window W4 display window

Claims (6)

In a machine tool equipped with a tool for grinding or cutting a workpiece, a device for measuring the position and shape of the tip of the tool,
an imaging means for photographing the tip shape of the tool;
a first illuminating means, which is provided together with the imaging means and illuminates the tool photographed by the imaging means;
a second illumination means arranged at a position facing the first illumination means for illuminating the tool photographed by the imaging means;
measuring means for measuring the position of the tip of the tool and the shape of the tip of the tool from the image captured by the imaging means;
and an image processing means for processing the image captured by the imaging means,
the imaging means comprises a camera and a lens,
The image processing means binarizes the image of the tool during operation captured by the imaging means and extracts the contour of the tool during operation,
The tool tip measuring device, wherein the measuring means acquires reference coordinates serving as a reference for measuring the tip position of the tool, and measures the contour of the tool extracted by the image processing means. 2. The tool tip measuring apparatus according to claim 1, wherein the lights emitted from said first illumination means and said second illumination means are parallel lights in which all light rays are parallel. Either the first illumination means or the second illumination means has a light source, and the other illumination means without a light source reflects the light illuminated by the illumination means having the light source. 3. The tool tip measuring device according to claim 1, wherein the tool is illuminated. 4. Said first illumination means has a light source, and said second illumination means illuminates said tool by reflecting the light illuminated by said first illumination means. The tool tip measuring device according to . 5. The tool tip measuring device according to claim 1, further comprising a gauge having a predetermined shape for obtaining said reference coordinates. In machine tools equipped with tools for grinding or cutting workpieces,
6. A tool tip measuring method comprising measuring the position and shape of the tip of a tool by using any one of the tool tip measuring devices according to claim 1.

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