JP7837210B2 - Tool measuring device and tool measuring method - Google Patents

Description

This disclosure relates to a tool measuring device and a tool measuring method.

Tools measuring devices for use in machine tools have been available for some time. These tools are used to measure end mills mounted on machining centers, particularly radius end mills and flat end mills, which have a flat bottom profile.

Japanese Patent Publication No. 2007-49489

Tools mounted on machining centers are measured using a tool measuring device equipped with an optical system that includes a light source and a camera with a focus. For ball end mills, the contour, including the bottom edge, can be accurately obtained by focusing the camera on the tool's central axis. However, for tools with a flat bottom edge, such as radius end mills and flat end mills, the flat bottom edge may be out of focus of the optical system, causing the bottom edge of the contour to blur. When the flat bottom edge of the contour is blurred in this way, it becomes difficult to accurately determine the bottom edge of the tool, and in particular, accurately detect the tool length.

This disclosure has been made with these points in mind, and aims to provide a tool measuring device and tool measuring method that can accurately detect the lowest end of a tool, even for tools with a flat bottom edge.

This disclosure relates to a first tool measuring device for measuring a tool attached to a machine tool, comprising: a light source for irradiating the tool with light; contour information acquisition means positioned opposite the light source with respect to the tool, forming an optical axis with the light source and obtaining contour information of the tool; a tool moving mechanism capable of moving the tool in at least a direction parallel to the optical axis; and a control device, wherein the light source and the contour information acquisition means have a focal range, and the control device controls the tool moving mechanism to move the tool in a direction parallel to the optical axis, positioning the tool so that the portion of the tool's lowest end facing the contour information acquisition means is within the focal range, and obtaining the lowest end contour information of the tool using the contour information acquisition means.

This disclosure relates to a second tool measuring device, wherein, in the first tool measuring device, the control device controls the tool moving mechanism to move the tool in a direction parallel to the optical axis, positions the tool so that its central axis is within the focal range, acquires overall contour information of the tool using the contour information acquisition means, and determines the lowest end of the tool based on the overall contour information.

This disclosure relates to a third tool measuring device in which, in the first or second tool measuring device, the control device determines the lowest end of the tool based on information obtained in advance.

This disclosure relates to a fourth tool measuring device, in which, in the first to third tool measuring devices described above, the light source consists of a strobe that emits illumination light, and the contour information acquisition means consists of a camera.

This disclosure relates to a fifth tool measuring device, in which, in the first to fourth tool measuring devices described above, the light source is a laser light irradiation device and the contour information acquisition means is a laser light receiving device.

This disclosure provides a tool measuring method using a tool measuring device comprising: a light source for irradiating a tool with light; contour information acquisition means positioned opposite the light source with respect to the tool, forming an optical axis with the light source and obtaining contour information of the tool; a tool moving mechanism capable of moving the tool in at least a direction parallel to the optical axis; and a control device. The first tool measuring method comprises the steps of: controlling the tool moving mechanism with the control device to move the tool in a direction parallel to the optical axis, positioning the tool so that the portion of the tool's lowest end facing the contour information acquisition means is within the focal range of the light source and the contour information acquisition means; and acquiring the lowest end contour information of the tool using the contour information acquisition means via the control device.

This disclosure provides a second tool measurement method, in which, in the first tool measurement method, the control device controls the tool movement mechanism to move the tool in a direction parallel to the optical axis, positions the tool so that its central axis is within the focal range, acquires overall contour information of the tool using the contour information acquisition means, and determines the lowest end of the tool based on the overall contour information using the control device.

This disclosure provides a third tool measuring method in which, in the first or second tool measuring method, the control unit determines the lowest end of the tool based on information obtained in advance.

This disclosure provides a fourth tool measurement method, in which, in the first to third tool measurement methods described above, the light source consists of a strobe that emits illumination light, and the contour information acquisition means consists of a camera.

This disclosure provides a fifth tool measurement method, in which, in the first to fourth tool measurement methods described above, the light source is a laser light irradiation device and the contour information acquisition means is a laser light receiving device.

As described above, this disclosure allows for the accurate detection of the lowest end of a tool with a flat bottom edge.

Figure 1 is a schematic diagram showing a tool measuring device according to an embodiment of the present disclosure. Figure 2A is a diagram showing the relationship between the camera, the illumination device, and the focal range of a tool measuring device according to an embodiment of this disclosure. Figure 2B shows the state in which the central axis of the tool is within the focal range. Figure 2C shows the tool moved away from the camera by a distance t. Figure 2D shows the overall outline as captured by the camera. Figure 2E shows the lowest edge contour as captured by the camera. Figure 3 shows a tool consisting of a ball end mill positioned between the camera and the lighting device. Figure 4A shows the relationship between the camera, the lighting device, and the focal range. Figure 4B shows a tool consisting of a ball end mill and its focal range. Figure 4C shows a tool consisting of a radial end mill and its focal range. Figure 4D shows a tool consisting of a flat end mill and its focal range. Figure 4E shows the overall outline of the ball end mill. Figure 4F shows the overall contour of the radial end mill. Figure 4G shows the overall contour of a flat end mill. Figure 5A shows a tool consisting of a radial end mill. Figure 5B is a bottom view of a tool consisting of a radial end mill. Figure 5C shows the overall contour of the radial end mill. Figure 6A shows the lowest end of a tool consisting of a radial end mill. Figure 6B is an enlarged view showing the bottom edge of Figure 6A. Figure 6C shows a tool made from a radial end mill that has undergone aging. Figure 7 shows a machine tool with a tool measuring device incorporated into it. Figure 8 shows the spindle head of a machine tool. Figure 9 shows a tool measuring device and a tool. Figure 10 is a flowchart illustrating the tool measurement method.

First, Figures 7 and 8 will describe the machine tool (machining center) 2 on which the tool 12 measured by the tool measuring device 1 according to this disclosure is mounted. Figure 7 is a schematic diagram showing the tool measuring device 1 and machine tool 2 according to an embodiment of this disclosure. The machine tool 2 shown in Figure 7 has a table 16 located on the upper surface of the bed 18 and a gate-shaped column 10, and the spindle head 4 is supported on the cross rail 8 of the column 10 via saddles 6. The spindle head 4 has a spindle 11, and the tool 12 is attached to the spindle 11.

Here, the spindle head 4 of the machine tool 2 will be explained in more detail with reference to Figure 8. Figure 8 is a schematic cross-sectional view showing the spindle head 4 of the machine tool 2. The spindle head 4 is of the built-in motor type and comprises a housing 31 and a spindle 11. The spindle 11 is formed in a cylindrical shape and is rotatably supported by the housing 31 by air bearings. The dashed line labeled L1 in Figure 8 indicates the axis of rotation (also called the central axis) that is the center of rotation of the spindle 11. The axis of rotation L1 of the spindle 11 is the axis of rotation of the rotation input from the spindle 11 to the tool 12. In the example shown in Figure 8, the axis of rotation L1 is parallel to the Z direction.

A tool holder 33 is provided at one end of the spindle 11 in the direction of the rotation axis L1 (the lower end in Figure 8). The tool holder 33 detachably holds the tool 12. The tool 12 is attached to the spindle 11 by holding it in the tool holder 33. A rotor 37 is integrally provided at the other end of the spindle 11 in the direction of the rotation axis L1 (the upper end in Figure 8), and a stator 39 is provided outside the rotor 37, spaced apart from it. The rotor 37 and stator 39 constitute the motor 35. As the rotor 37 of the motor 35 rotates relative to the stator 39, the spindle 11, which is integrated with the rotor 37, rotates. As the spindle 11 rotates, the tool 12 attached to the spindle 11 also rotates around the rotation axis (central axis) L1. A spindle rotation angle sensor 23 is also provided on the outer circumference of the spindle 11.

Here, for the sake of explanation, we define one predetermined direction on the horizontal plane as the X direction (X-axis direction), another predetermined direction on the horizontal plane perpendicular to the X direction as the Y direction (Y-axis direction), and the vertical direction perpendicular to both the X and Y directions as the Z direction (Z-axis direction).

The table 16 is movable in the X-axis direction relative to the bed 18, and the saddle 6 is movable in the Y-axis direction along the cross rail 8. The spindle head 4 is movable in the Z-axis direction relative to the saddle 6. By moving these three axes, the tool 12 can be moved in three dimensions relative to the workpiece 14 placed on the table 16. Furthermore, by rotating the spindle 11 to rotate the tool 12, and then bringing the tool 12 into contact with the workpiece 14, the workpiece 14 can be machined. In this embodiment, the table 16 and the saddle 6 constitute a tool movement mechanism 2A that moves the tool 12 in three dimensions: the X-axis, Y-axis, and Z-axis directions.

Next, the tool 12 mounted on the machine tool 2 will be described. As shown in Figure 8, the tool 12 has an operating part 46 and a shaft part 49, and a contour with a flat bottom edge, and is, for example, a radius end mill or a flat end mill.

Next, the tool measuring device 1 according to this disclosure will be described with reference to Figures 7 to 9. As described above, the tool measuring device 1 measures the tool 12 set on the spindle 11 of the machine tool 2. As shown in Figures 7 to 9, the tool measuring device 1 is installed at the end of the table 16.

Figure 9 shows a tool measuring device 1 for measuring a tool 12. As shown in Figures 7 to 9, the tool measuring device 1 comprises a camera (contour information acquisition means) 22 for photographing the tool 12, a lighting device (light source) 24, and a control device 20. By moving the tool 12 between the lighting device 24 and the camera 22 using the tool moving mechanism 2A described above, the tool 12 can be measured using the tool measuring device 1. As shown in Figure 9, the camera 22 photographs the tool 12 while it is positioned between the camera 22 and the lighting device 24.

The control device 20 controls the tool measuring device 1, but this control device 20 may also control the entire machine tool 2, including the tool moving mechanism 2A. In this case, the control device 20 may also control the rotational speed and rotational angle positioning of the spindle 11. The control device 20 is configured to include, for example, a CPU and memory (not shown).

Next, the camera 22 and illumination device 24 will be described with reference to Figures 1 and 9. The camera 22 photographs the tool 12 located between the camera 22 and the illumination device 24. Specifically, the camera 22 photographs 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 equipped with a global shutter to photograph the tool 12. As an example, the camera 22 has a high-speed shutter, allowing it to capture still images even when the tool 12 is rotating at several thousand revolutions per minute. In this case, the shutter speed of the camera 22 when photographing the tool 12 is set to a short time such that the image of the rotating tool 12 becomes almost a still image. The camera 22 may also be equipped with a zoom lens, and the magnification can be controlled by the control device 20. As shown in Figure 9, the outline of the tool 12 is captured by illuminating the tool 12 from behind with light from the illumination device 24.

Next, the lighting device 24 will be described. As shown in Figures 1 and 9, the lighting device 24 has a strobe 24A, and the camera 22 and lighting device 24 are positioned so that the rotating tool 12 is sandwiched between the camera 22 and the lighting device 24. In this case, light (illumination light) is emitted from the strobe 24A towards the tool 12 and the camera 22, and the camera 22 photographs the tool 12. At this time, the strobe 24A is configured to emit parallel light toward the tool 12. The parallel light emitted from the strobe 24A and the camera 22 have a certain focal range, as will be described later.

When photographing the tool 12 with camera 22, the strobe 24A functions as a backlight, allowing the camera 22 to capture the outline of the tool 12.

Next, the configuration of the camera 22 and the strobe 24A will be further explained. The direction of propagation of the parallel light emitted by the strobe 24A is, for example, in the X direction. The direction of propagation of the parallel light emitted by the strobe 24A is perpendicular to the rotation axis L1 of the main axis 11.

In this embodiment, the illumination device 24, consisting of the camera 22 and the strobe 24A, constitutes an optical system 22A, which has an optical axis L2. Furthermore, the optical axis L2 of the optical system 22A is perpendicular to the rotation axis L1 of the tool 12.

As described above, the lighting device 24 has a strobe 24A. The lighting device 24 with the strobe 24A is preferably used when the tool 12 rotates at high speed, particularly when the tool 12 rotates at a rotational speed of 10,000 revolutions per minute or more. When the lighting device 24 has a strobe 24A, the light from the strobe 24A is adjusted to obtain a clearer still image of the tool 12 and to photograph the tool 12 in a shorter time. For example, the flash of the strobe 24A is adjusted so that the flashing time of the strobe 24A is shorter than the time the camera 22 shutter is open, and the strobe 24A flashes within the time the camera 22 shutter is open.

The flash output of the strobe 24A may be adjusted so that it flashes during the time the camera 22's shutter is open (the time the camera 22's shutter is fully open) in response to the shooting command output from the control device 20 to the camera 22.

The strobe 24A may be adjusted to flash from a time slightly after the camera 22 begins opening the shutter until just before the camera 22 begins closing the shutter.

For example, if camera 22 is configured to immediately open its shutter when the control device 20 outputs a shooting command to camera 22, it is conceivable that the control device 20 could use the measurement result of the main axis rotation angle sensor 23 as a trigger to output a shooting command to the camera 22's shutter and simultaneously output an instruction to the strobe 24A to fire. However, in this case, there is a time lag between the output of the shooting command to camera 22 and the full opening of the camera 22's shutter, so it is possible that the strobe 24A may stop firing before the camera 22's shutter is fully open. To avoid this, the timing of the strobe 24A's start of firing can be adjusted to be delayed compared to the timing of the camera 22's shutter opening. By delaying the start of the strobe 24A's firing in this way, the strobe 24A can stop firing at the moment the shutter is fully open.

In this embodiment, the system is specifically adjusted so that the flash 24A does not start firing before the camera 22's shutter is fully open. Furthermore, the timing of the shooting command to the camera 22 and the flash command to the flash 24A are adjusted so that the flash 24A does not fire when the camera 22's shutter is closed or partially closed.

When using the strobe 24A to take still images of the tool 12, the outline of the tool 12 can be captured even if the shutter speed of the camera 22 is set relatively slow. Furthermore, if an LED is used as the light source for the strobe 24A, the high brightness of the LED allows for a clear capture of the tool 12's outline without needing to darken the shooting environment.

If the camera 22 is equipped with a high-speed shutter and the illumination device 24 has a strobe 24A, by using a strobe 61 with a short flash duration of a few microseconds, the contour of the rotating tool 12 can be photographed by the camera 22, even when the tool 12 is rotating at a particularly high speed.

The illumination device 24 according to the embodiment of this disclosure has a strobe 24A, which is configured to emit light toward the tool 12. Therefore, the timing of the strobe 24A's emission is adjusted so that it emits light within the time the camera 22's shutter is open. This allows the tool 12 to be photographed in a shorter time compared to when images are captured by opening and closing the camera 22's shutter. As a result, clear images of the rotating tool 12 can be obtained inexpensively and easily.

If a lighting device 24 without a strobe 24A were used, it would be necessary to use a camera 22 capable of continuously capturing sufficiently clear images with a short shutter speed. This would require a very expensive camera 22. In contrast, because the strobe 24A has a fast start-up time and can emit light for short periods, using a lighting device 24 with a strobe 24A allows for the capture of clear images of the rotating tool 12.

Incidentally, the optical system 22A, consisting of the camera 22 and the illumination device 24, has an optical axis L2 perpendicular to the rotation axis L1 of the tool 12, and the optical system 22A has a constant focal range (depth of field) S (see Figures 2A to 2C).

Next, the control device 20 will be described. The control device 20 includes a tool movement mechanism control unit 25 that drives and controls the tool movement mechanism 2A, and a calculation unit 27 that calculates contour information of the tool 12 based on the image information of the tool 12 captured by the camera 22 (see Figure 7).

Next, a method for measuring the tool 12 mounted on the spindle 11 of the machine tool 2 will be described. In particular, a method for measuring the tool 12 while it continues to rotate will be explained using Figures 2A to 2E and 10, as shown in Figures 7 to 9, where the workpiece 14 is placed on the table 16, the tool 12 is rotated to process the workpiece 14, and then the tool 12 is measured.

First, as shown in the flowchart of Figure 10, the tool movement mechanism control unit 25 of the control device 20 drives and controls the tool movement mechanism 2A to bring the tool 12 between the camera 22 and the lighting device 24 of the tool measuring device 1 (see Figures 2A, 2B, and 9).

When the tool 12 is positioned between the camera 22 and the illumination device 24, the tool 12 is positioned so that its central axis L1 falls within the focal range S of the optical system 22A. During this time, the tool 12 continues to rotate.

Next, illumination light is emitted from the strobe 24A of the lighting device 24 towards the operating part 46 of the rotating tool 12. This illumination light is blocked by the operating part 46 of the tool 12, and the camera 22 continuously photographs the operating part 46. The images captured by the camera 22 are sent to the calculation unit 27, where these images are combined to obtain the overall contour 50 of the operating part 46 of the tool 12.

Here, Figure 2A shows the relationship between the camera 22, the illumination device 24, and the focal range S, and Figure 2B shows the state in which the central axis L1 of the tool 12 is within the focal range S. The upper part of Figure 2B shows the side view of the operating part 46 of the rotating tool 12, and the lower part shows the bottom surface 60 of the rotating tool 12. The overall contour 50 of the operating part 46 (hereinafter also referred to as the contour of the tool 12) 50, as captured by the camera 22, is shown in Figure 2D. In Figure 2B, contour-forming lines 71 that form the overall contour 50 of the tool 12 are shown on the side and bottom surface 60 of the tool 12.

As shown in Figure 2D, the tool 12 is a radius end mill or a flat end mill, for example, a radius end mill. Therefore, the overall contour 50 of the tool 12 viewed from the side has a side edge 50a and a flat bottom edge 50b. In this embodiment, the flat bottom edge 50b of the overall contour 50 of the tool 12 indicates the lowest end of the tool 12.

Furthermore, a curved portion 50d is provided between the side edge 50a and the flat bottom edge 50b of the overall contour 50 of the tool 12, and a boundary 50c is formed between the flat bottom edge 50b and the curved portion 50d.

As described above, the tool 12 is positioned so that its central axis L1 falls within the focal range S of the optical system 22A, which consists of the camera 22 and the illumination device 24. The camera 22 captures the outline (overall outline) 50 of the tool 12 as seen from the side. Therefore, except for the vicinity of the boundary 50c of the flat bottom edge 50b that constitutes the lowest end, most of the flat bottom edge 50b, including the central portion, does not fall within the focal range S and becomes blurred, forming a blurred region 51 (see Figure 2D). Furthermore, the portion of the flat bottom edge 50b near the boundary 50c overlaps with the blurred region 51 of the central portion of the flat bottom edge 50b, resulting in a problem with sharpness. However, the side edges 50a of the overall outline 50 fall within the focal range S and are therefore relatively sharp.

In this embodiment, as described above, the tool 12 is first positioned so that its central axis L1 falls within the focal range S of the optical system 22A. Next, illumination light is emitted from the illumination device 24, and the tool 12 is photographed by the camera 22. By photographing the tool 12 with the camera 22 in this way, the overall contour 50 of the tool 12 is obtained (see Figure 2D).

Next, the calculation unit 27 of the control device 20 identifies the flat bottom edge 50b and the boundary 50c between the flat bottom edge 50b and the curved portion 50d based on the overall contour 50 shown in Figure 2D, which is acquired by the camera 22. The calculation unit 27 then determines that the boundary 50c of the overall contour 50 corresponds to the circle 50c1 where the lowest end of the tool 12 is located on the bottom surface 60, and calculates the distance t between the circle 50c1 where the lowest end of the tool 12 is located and the central axis L1 (see Figure 2B). This distance t is the amount of displacement between the portion 50c2 on the camera 22 side of the circle 50c1 where the lowest end of the tool 12 is located and the focal range S. Note that in Figure 2B, the circle 50c1 where the lowest end of the tool 12 is located, shown on the bottom surface 60, coincides with the contour forming line 71 that forms the overall contour 50 of the tool 12.

Next, the tool movement mechanism control unit 25 of the control device 20 drives and controls the tool movement mechanism 2A to move the tool 12 away from the camera 22 by a distance t along a direction parallel to the optical axis L2. By moving the tool 12 in this way using the tool movement mechanism 2A, the tool 12 is positioned so that the portion 50c2 of the circle 50c1 corresponding to the lowest point on the bottom surface 60, on the camera 22 side, falls within the focal range S (see Figure 2C).

Subsequently, illumination light is emitted from the lighting device 24, the tool 12 is photographed by the camera 22, and the arithmetic unit 27 obtains the side view contour (lowest end contour) 50A (see Figure 2E).

In the lowermost contour 50A of the tool 12 shown in Figure 2E, the central portion 50b1 of the flat bottom edge 50b that constitutes the lowermost end of the tool 12 is clearly shown because it falls within the focal range S. In the lowermost contour 50A of the tool 12 shown in Figure 2E, the vicinity of the boundary 50c and the side edges 50a of the flat bottom edge 50b fall outside the focal range S, forming a blurred region 51.

The images of the tool 12 obtained by the camera 22 are sent to the calculation unit 27, and these images are combined to obtain the lowest end contour 50A in the calculation unit 27.

According to this embodiment, the tool 12 is moved away from the camera 22 by a distance t, which is the amount of displacement between the portion 50c2 of the circle 50c1 on the camera 22 side and the focal range S, along a direction parallel to the optical axis L2. Next, by photographing the tool 12 with the camera 22 in this state, the calculation unit 27 can obtain the contour (lowest end contour) 50A of the tool 12.

At the lowest contour 50A, the central portion 50b1 of the flat bottom edge 50b that constitutes the lowest end of the tool 12 falls within the focal range S and is therefore clearly shown. Next, the calculation unit 27 identifies the lowest end of the tool 12 based on the clearly shown central portion 50b1 of the flat bottom edge 50b that constitutes the lowest end. The calculation unit 27 can then determine the tool length of the tool 12 based on the identified lowest end, enabling accurate measurement of the tool length of the tool 12.

Next, the effects and advantages of the present invention will be further explained with reference to Figures 3 to 6C, in comparison with comparative examples.

Figure 3 shows an optical system 22A consisting of a camera 22 and an illumination device 24. This optical system 22A has an optical axis L2 and a fixed focal range S.

In Figure 3, a tool 12, having an overall contour 50 with an arc-shaped bottom edge 50b2, similar to a ball mill, is positioned between the camera 22 and the illumination device 24. In this case, the lowest end of the tool 12 coincides with the central axis L1 of the tool 12 (see Figures 4A and 4B). As shown in Figures 4A and 4B, the tool 12 is positioned so that its central axis L1 falls within the focal range S, and the camera 22 captures a photograph to obtain the overall contour 50 as seen from the side of the tool 12 (Figure 4E). This overall contour 50 has a side edge 50a and an arc-shaped bottom edge 50b2.

In the overall contour 50 shown in Figure 4E, the lowest end of the tool 12 lies on the central axis L1 of the tool 12. Therefore, by positioning the tool 12 so that its central axis L1 falls within the focal range S, the lowest end of the tool 12 can be clearly indicated by the overall contour 50. This allows for accurate detection of the lowest end of the tool 12 based on the overall contour 50. In Figure 4B, the upper part shows the side of the tool 12, and the lower part shows the bottom surface 60 of the tool 12. Furthermore, contour-forming lines 71 that form the overall contour 50 of the tool 12 are shown on the side and bottom surface 60 of the tool 12.

In contrast, when the tool 12 is a radius end mill (Figure 4C), the tool 12 is positioned so that its central axis L1 falls within the focal range S, and the overall contour 50 of the tool 12 as seen from the side is obtained by photographing it with the camera 22 (Figure 4F). This overall contour 50 has, as described above, a side edge 50a, a flat bottom edge 50b, a curved portion 50d, and a boundary 50c. Of these, most of the flat bottom edge 50b, which constitutes the lowest end of the tool 12, is blurred, forming a blurred region 51. Figure 4C shows the side view and the bottom surface 60 of the tool 12, and the distance t between the circle 50c1 on the bottom surface 60 where the lowest end is located and the central axis L1 is shown. Furthermore, contour-forming lines 71 that form the overall contour 50 of the tool 12 are shown on the side view and the bottom surface 60 of the tool 12.

If the tool 12 is a radius end mill, the overall contour 50 obtained by photographing with the camera 22 will be described further.

As shown in Figures 5A to 5C, the tool 12, which is made of a radius end mill, has a bottom surface 12A, and the lowest end 12B is formed near the periphery of the bottom surface 12A. Here, Figure 5A shows the side view of the tool 12, and Figure 5B shows the bottom surface 60 of the tool 12. The overall contour 50 is obtained by photographing such a tool 12 with a camera 22 (see Figure 5C).

The lowest end 12B of the tool 12 lies on the circle 50c1 on the bottom surface 60 of the tool 12 (see Figure 5B). The tool 12 is then positioned so that its central axis L1 is within the focal range S, and subsequently photographed by the camera 22. This obtains the overall contour 50, which includes the side edge 50a, the flat bottom edge 50b, the curved portion 50d, and the boundary 50c.

Furthermore, the flat bottom edge 50b of the overall contour 50 indicates the lowest end 12B of the tool 12. However, since most of the flat bottom edge 50b is outside the focal range S, the flat bottom edge 50b is blurred except near the boundary 50c, forming a blurred region 51. Also, even the area near the boundary 50c of the flat bottom edge 50b is not necessarily sharp because it partially overlaps with the blurred portion 72 of the bottom surface 60 of the tool 12 (the portion closer to the camera 22) (see Figure 5B). Therefore, it is difficult to determine the lowest end 12B of the tool 12 from the overall contour 50 of the tool 12. Note that the side view of the tool 12 shown in Figure 5A and the bottom surface 60 of the tool 12 shown in Figure 5B show contour-forming lines 71 that form the overall contour 50 of the tool 12.

Furthermore, as shown in Figures 6A to 6C, as the tool 12 is used, the cutting surface of the tool 12 recedes due to aging, and the lowest end 12B of the tool 12 moves inward.

In this case, the flat bottom edge 50b of the overall contour 50 obtained by photographing the tool 12 with a camera becomes unclear near the boundaries 50c on both sides, making it more difficult to detect the lowest end 12B from the overall contour 50.

Next, the case where the tool 12 is a flat end mill will be explained with reference to Figure 4D. As shown in Figure 4D, by positioning the tool 12 so that its central axis L1 falls within the focal range S and photographing the tool 12 with the camera 22, the overall contour 50 of the tool 12 as seen from the side is obtained (Figure 4G). This overall contour 50 has side edges 50a and a flat bottom edge 50b, and the majority of the flat bottom edge 50b that constitutes the lowest end forms a blurred region 51, similar to the case of a radius end mill.

In Figure 4D, the side view of the tool 12 is shown at the top, and the bottom surface 60 of the tool 12 is shown below it. Furthermore, contour-forming lines 71, which form the overall contour 50 of the tool 12, are shown on the side view and the bottom surface 60 of the tool 12.

In the overall contour 50 viewed from the side as shown in Figure 4G, the lowest end of the tool 12 is at the boundary 50c between the side edge 50a and the flat bottom edge 50b, and this boundary 50c corresponds to the outer peripheral edge 50c3 of the bottom surface 60 of the tool 12.

Furthermore, Figure 4D shows the distance t1 between the outer edge 50c3 and the central axis L1.

In the overall contour 50 of the tool 12, which is made from a flat end mill obtained in this way, most of the flat bottom edge 50b is blurred, making it difficult to determine the lowest point of the tool 12 from the flat bottom edge 50b.

In contrast, according to this embodiment, whether the tool 12 is a radial end mill (Figures 4C and 4F) or a flat end mill (Figures 4D and 4G), the tool 12 is moved away from the camera 22 by a distance t or t1, respectively, along a direction parallel to the optical axis L2. In this state, the tool 12 is photographed by the camera 22 to obtain the contour (lowest end contour) 50A of the tool 12. In this case, the central portion of the flat bottom edge 50b of this lowest end contour 50A falls within the focal range S and is therefore clearly shown. The calculation unit 27 identifies the lowest end based on this clearly shown central portion of the flat bottom edge 50b, and the tool length of the tool 12 can be determined from this lowest end.

In the above embodiment, an example was shown in which the optical system was configured with a camera (contour information acquisition means) 22 and an illumination device (light source) 24 consisting of a strobe 24A. However, the system is not limited to this configuration; a laser light emitting unit that emits laser light may be used as the light source, and a laser light receiving unit that receives laser light may be used as the contour information acquisition unit. An optical system having a certain focal range may be configured from the laser light emitting unit and the laser light receiving unit.

Furthermore, an optical system having a certain focal range may be constructed from a laser light emitting unit and a laser light receiving unit consisting of light-receiving elements arranged in a line.

Furthermore, in the above embodiment, the tool 12 is photographed by the camera 22 to obtain the overall contour 50, the amount of displacement t between the boundary 50c of the overall contour 50 and the circle 50c1 where the central axis L1 of the tool 12 and the lowest point of the tool 12 are located is determined, and an example is shown in which the tool 12 is moved away from the camera 22 by this amount of displacement t. However, the method is not limited to this; a predetermined value (for example, a catalog value) is used as the amount of displacement t between the central axis L1 of the tool 12 and the circle 50c1 where the lowest point of the tool 12 is located, and the tool 12 is moved away from the camera 22 by this amount of displacement t.

1 Tool measuring device 2 Machine tool 2A Tool moving mechanism 11 Spindle 12 Tool 12A Bottom surface 12B Lower end 20 Control device 22 Camera 22A Optical system 24 Illumination device 25 Tool moving mechanism control unit 27 Calculation unit 46 Operating unit 49 Shaft part 50 Overall contour 50A Lower end contour 50a Side edge 50b Flat bottom edge 50b1 Central part 50c Boundary 50c1 Circle 50c2 Camera side part 50d Curved part 60 Bottom surface

Claims (10)

In a tool measuring device for measuring tools attached to a machine tool,
A light source that irradiates the tool with light,
With respect to the tool, a contour information acquisition means is provided which is positioned opposite the light source, forms an optical axis with the light source, and obtains contour information of the tool.
A tool moving mechanism capable of moving the tool in at least a direction parallel to the optical axis,
Equipped with a control device,
The light source and the contour information acquisition means have a focal range.
The control device controls the tool moving mechanism to move the tool in a direction parallel to the optical axis, positions the lowermost end of the tool so that the portion on the contour information acquisition means side is within the focal range, and obtains the contour information of the lowermost end of the tool using the contour information acquisition means; this is a tool measuring device. The control device controls the tool moving mechanism to move the tool in a direction parallel to the optical axis, positioning the tool so that its central axis is within the focal range, and the contour information acquisition means acquires the overall contour information of the tool.
The tool measuring device according to claim 1, wherein the control device determines the lowest end of the tool based on the overall contour information. The tool measuring device according to claim 1, wherein, instead of obtaining the lowest end contour information of the tool using the contour information acquisition means, the control device moves the tool in a direction parallel to the optical axis based on catalog information obtained in advance to determine the lowest end of the tool. The tool measuring device according to claim 1, wherein the light source consists of a strobe that emits illumination light, and the contour information acquisition means consists of a camera. The tool measuring device according to claim 1, wherein the light source consists of a laser light irradiation device, and the contour information acquisition means consists of a laser light receiving device. A light source that illuminates the tool,
With respect to the tool, a contour information acquisition means is provided which is positioned opposite the light source, forms an optical axis with the light source, and obtains contour information of the tool.
A tool moving mechanism capable of moving the tool in at least a direction parallel to the optical axis,
In a tool measuring method using a tool measuring device equipped with a control device,
The control device controls the tool movement mechanism to move the tool in a direction parallel to the optical axis, and positions the lowermost end of the tool, specifically the portion on the contour information acquisition means side, within the focal range of the light source and the contour information acquisition means.
A tool measuring method comprising the step of acquiring the lowest end contour information of the tool using the contour information acquisition means via the control device. The tool measurement method according to claim 6, comprising: controlling the tool movement mechanism with the control device to move the tool in a direction parallel to the optical axis, positioning the tool so that its central axis is within the focal range, acquiring overall contour information of the tool with the contour information acquisition means, and determining the lowest end of the tool based on the overall contour information with the control device. The tool measurement method according to claim 6, wherein the control device, instead of obtaining the lowest end contour information of the tool using the contour information acquisition means, moves the tool in a direction parallel to the optical axis based on catalog information obtained in advance to determine the lowest end of the tool. The tool measurement method according to claim 6, wherein the light source consists of a strobe that emits illumination light, and the contour information acquisition means consists of a camera. The tool measurement method according to claim 6, wherein the light source consists of a laser light irradiation device, and the contour information acquisition means consists of a laser light receiving device.