JPH06137842A - Method and device for measuring rotary tool blade part form - Google Patents

Abstract

PURPOSE:To measure the blade part profile form of a rotary tool with helical tooth such as ball end mill, etc., accurately and by a simple operation. CONSTITUTION:An axis A of a rotary tool 3 is positioned at a right angle to an optical axis P of a tool maker's microscope 1 with a TV camera 19. First the focus point of the tool maker's microscope 1 is made flush with the height of axis of the rotary tool, and fixed. Then, the optical axis of the tool maker's microscope 1 is positioned at multiple measuring points (1),... (n) on the blade part profile line of the rotary tool 3 in order, a cutting blade of the rotary tool 3 at each measuring point is detected by an image processing device connected to the TV camera 19, and the rotary tool 3 is positioned around its axis A so that the cutting blade is made coincide with the focus position of the tool maker's microscope 1. Here the coordinate of the cutting blade in X-axis and Y-axis directions at each measuring point is measured and, from measured values, the dimensions of the tool top end or form accuracy are calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for accurately measuring the shape and size of a rotary tool having a twisting blade such as a ball end mill or a drill.

[0002]

2. Description of the Related Art A ball end mill is used as a tool for three-dimensionally machining a surface of a molding die or the like. And in recent years, the numerical control machine often directly cuts the three-dimensional shape of the work, and the error factor is greatly reduced compared to the copy machining.Therefore, the cutting edge shape of the tool for improving the machining accuracy, Especially, it is a very important requirement to maintain the roundness and radius value of the tip spherical portion with high accuracy. In particular, when the tool is re-polished and used, it is very important to measure and grasp whether the tip end portion of the tool has an appropriate shape or size in order to maintain the finish accuracy of the work. Conventionally, in measuring such a tool shape, there are a method of indirectly measuring with a magnifying projector and a method of using a three-dimensional measuring device while rotating the tool at a constant angle, but a ball end mill, etc. However, since it usually has a twisting blade and there is a cutting edge lead even up to the top of the spherical tip portion, it is difficult to measure this portion, and it takes a long time for measurement, and there is a problem that considerable labor and skill are required.

A measuring method in which these problems have been improved is disclosed in JP-A-63-182505. This is to position one end of the measurement area of the line sensor arranged in the direction orthogonal to the axis of the tool substantially at the center of the tip R inside the tool tip, and then move the line sensor to one end of the measurement area by the measuring head driving means. While rotating by a predetermined angle about the horizontal axis in the direction orthogonal to the tool around the center of the tool, by rotating the tool once around the tool axis for each angle, the end surface of the tool obtained by the line sensor A method to calculate the radius and shape accuracy of the tip spherical portion of the tool by calculating the measurement data related to the position and the measurement data in the axial direction of the tool obtained by the touch sensor using the least square method of the circle in the control / calculation unit. Is.

[0004]

However, this Japanese Unexamined Patent Application Publication No.
The method of No. 3-182505 also has the following problems,
It was not reliable enough. That is, since the line sensor has a beam width b as shown in FIG. 6, when the tool tip D is smaller than the beam width b, it is difficult for the line sensor to determine the blade boundary position. The display of the coordinates of the cutting edge of the tool tip became incorrect. Further, since the point at which the value indicated by the line sensor is maximum is determined as the cutting edge while rotating the tool, there is a problem in that a portion other than the cutting edge is caught. further,
Since the tip shape of the tool is measured with R-θ coordinates,
At the time of data processing in the arithmetic unit, there is a disadvantage that an arithmetic error for replacing with the XY coordinates occurs. The present invention eliminates these drawbacks of the prior art, and provides a measuring method and a measuring device used therefor capable of measuring the contour shape of a blade portion of a rotary tool having a twisting blade such as a ball end mill with high precision and simple operation. It is provided.

[0005]

The structure of the present invention will be described with reference to FIG. 1 and FIGS. 2 and 3 corresponding to the embodiment. The method of the present invention uses a TV camera 19 for converting an image into an electric signal.
The axis A of the rotary tool 3 is arranged in the direction perpendicular to the optical axis P of the tool microscope unit 1 having
Is fixed to match the height h of the axis A of the rotary tool 3, and then the optical axis P of the tool microscope unit 1 is set to a plurality of measurement points (1) (n) on the contour line of the blade of the rotary tool 3. ) Sequentially, and the image processing device 30 connected to the TV camera 19 detects the cutting edge portions ε1 ... εn of the rotary tool 3 at each measurement point (1) ... (n) to detect the tool microscope unit 1 Rotating tool 3 to match the focus position
Is angularly positioned around its axis A, the coordinates of the cutting edge portion in the X-axis and Y-axis directions at each measurement point are measured, and the dimension or shape accuracy of the tool tip is calculated based on these measured values. Is the way to do it.

The apparatus of the present invention used for this has a light source 2, lens systems 18 and 20, and a TV camera 19 for converting an image into an electric signal, and the X axis and the X axis on a plane orthogonal to the optical axis P thereof. A tool microscope unit 1 equipped with an XY table 4 movable in the Y-axis direction, in which the axis A of the rotary tool 3 is kept in the XY table 4 in a direction perpendicular to the optical axis P.
An image processing device 30 is provided which is provided with an angle indexing table 24 which is rotatable around an arbitrary angle, and which processes an image signal of the TV camera 19 to detect a cutting edge portion εm of the rotary tool 3, and an image processing device 30. Computer 3 which receives the signal of the above, calculates the numerical value of the blade shape of the rotary tool 3, and issues a control command for each axis of X, Y and A according to a predetermined program.
3 and a control command from the computer 33, movement of the XY table 4 in the X-axis and Y-axis directions and an angle indexing table 24.
And a three-axis controller 37 for controlling the rotation angle of the measuring device.

[0007]

The operation of the present invention will be described with reference to FIG. Figure 1
When measuring a rotary tool 3 having a shape such as (a), measurement points (1), (2), (3), ... () on the contour line of the blade portion of the rotary tool 3 as shown in (b) of FIG. n) is set. The optical axis P of the tool microscope unit whose focus position matches the height h of the axis A of the rotary tool 3 is located at the measurement point (1), and the rotary tool is rotated by the image processing device connected to the TV camera of the tool microscope unit. The cutting edge portion ε1 of 3 is detected. The image of the cutting edge portion ε1 is initially blurred, but the rotary tool 3
Is rotated about its axis A, and when the angular position of the cutting edge portion ε1 matches the focal position of the microscope as shown in FIG. 1C, the image processing apparatus detects it as the maximum contrast point of the image, The rotation of the rotary tool 3 is stopped and angular positioning is performed.

Since the cutting edge portion ε1 of the measuring point (1) thus angularly positioned is located at the same height h as the axis of the rotary tool 3, the measuring point (1) is measured by The X-axis and Y-axis coordinates are accurately captured by the tool microscope unit. Similarly, when measuring at the measurement point (2), the relationship between the optical axis P of the tool microscope unit 1 and the angular position of the cutting edge portion ε2 of the rotary tool 3 is shown as (d) in FIG. When measuring at the measurement point (3), it is shown as (e) in FIG. In both cases, the height h of the cutting edge portion at the measurement point matches the focus position of the microscope, and is the same height as the axis of the rotary tool.
The coordinates of the axes and the Y axis can be accurately captured.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a view showing the measuring section of this device, in which the pedestal portion 2 of the tool microscope 1 has a transmitted light source 2a so that the transmitted light is projected upward along an upright optical axis P. It has become. An XY table 4 is laid on the pedestal portion 2 so as to be movable in the left-right (X-axis) direction and the front-back (Y-axis) direction in a plane perpendicular to the optical axis P. The XY table 4 has a transparent portion 5 in the center thereof, and is guided by a left-right direction guide 6 and a front-back direction guide 7, and each has a precision feed screw 8,
The X-axis is driven by the pulse motor 10 and the Y-axis is driven by the pulse motor 11 via 9. Further, the XY table 4 is provided with position sensors 12 and 13 that electrically detect respective positions in the X-axis direction and the Y-axis direction. A column 14 is provided on the back side of the pedestal part, and a microscope barrel 17 is vertically attached to a bracket 16 that moves up and down along a vertical guide 15. An objective lens 18 with a revolver is provided below the microscope barrel 17, and a TV camera is provided at the upper end. The CCD camera 19 is An eyepiece lens 20 is provided obliquely downward in the middle portion. In addition, 21 is a bracket 16
Is a rotary knob for moving up and down, and 22 is a light source when the reflected light is used.

The XY table 4 is attached with a mounting seat 23.
An angle indexing table 24 for rotating the rotary tool 3 is attached with its rotation axis A parallel to the X axis. The angle indexing table 24 is provided with a collet chuck 25 on the front surface side so as to hold the rotary tool 3, and on the rear surface side, an arbitrary angle can be rotated by a pulse motor 28 via a pulley and a belt 27 for angular positioning. It is done like this.

FIG. 3 is a block diagram showing the overall configuration including the control / calculation unit of this apparatus. The CCD camera 19 used as a TV camera has a camera amplifier 29.
Is connected to the image processing device 30 via the
A keyboard 31 for inputting various data and a monochrome monitor 32 for displaying a microscope screen are connected to 0. A computer 34 connected to the image processing apparatus 30 is connected to a keyboard 34 for inputting various data, an RGB monitor 35 for displaying each output information of the shape and numerical value of the blade contour, and a printer 36. . A three-axis controller 37 that controls the movement of the X-axis and Y-axis of the XY table 4 and the rotation of the A-axis of the angle indexing table 24 is connected to the computer 33.
In FIG. 7, pulse motors 38, 39, 40 for driving the X-axis, Y-axis, and A-axis are respectively driver amplifiers 41,
It is connected via 42 and 43. The position sensors 12 and 13 in the X-axis and Y-axis directions of the XY table 4 are connected to a display unit 44 that numerically displays the position information, and further connected to a computer 33.

FIG. 4 shows a flow chart of the measurement procedure by the apparatus of the embodiment of the present invention. For example, when measuring a ball end mill, first, the measuring device is set to the measurement mode of the ball end mill, and basic data to be measured, such as the lot number, diameter, diameter of the blade portion R, twist angle, number of blades, and their numbers, are calculated by a computer. Enter in 33. Next, a reference center (not shown) is attached to the angle indexing table 24 by the collet chuck 25, and the XY table 4 is further moved in the X-axis and Y-axis directions so that the peripheral edge of the surface corresponding to the axial height of the reference center tip ( The portion corresponding to the cutting edge of the tool) is aligned with the optical axis P of the tool microscope 1. Here, the tool microscope 1 is adjusted so that its focal position coincides with the axis line of the reference center, and the clearest image is displayed by the image monitor 30 on the monochrome monitor 32.
Fix and fix the focus position at the position displayed on. In addition to using the reference center, a reference block may be attached to the XY table 4 for the operation of adjusting the focus position. In addition, a two-blade ball end mill or the like may be used, and the tip surface of the reference edge may be aligned with the axis. When it has, the tip of the ball end mill itself can be used as the axis reference.

Next, the ball end mill 3 as shown in FIG. 1A to be measured is attached to the angle indexing table 24 by the collet chuck 25. When the button for switching to automatic measurement is pressed here, the 3-axis controller 3 is operated by the measurement program command of the ball end mill from the computer 33.
7, the XY table 4 is moved in the X-axis and Y-axis directions, and is set on the contour line of the blade portion R of the ball end mill 3 as shown in (b) to (f) of FIG. 1),
(2) ... (m) ... (n) are sequentially measured by the tool microscope 1
According to the position of the optical axis P, the cutting edge portions ε1, ε2 ... εm ... εn of the ball end mill 3 are automatically measured at the respective measurement points. At the measurement point (m), the computer 33 operates the three-axis controller 37 in response to a signal from the image processing device 30 to continuously load the image signal data into the image processing device 30 while rotating the angle indexing table 24, The angle position where the contrast of the image of the cutting edge portion εm of the ball end mill 3 at the measurement point (m) is maximum is determined by the image processing device 30, and as shown in (c) to (f) of FIG. The tool microscope 1 is automatically focused by matching the rotation angle of the A-axis of the angle indexing table 24 with the angle position.
At the same time, the cutting edge portion εm at the measurement point (m) is angularly positioned at the same height as the height h of the axis A of the ball end mill 3, and the position of the cutting edge portion εm in the X-axis and Y-axis directions is the tool microscope 1. Is exactly represented in the field of view.

The image at the measuring point (m) of the ball end mill 3 by the image processing device 30 becomes as shown in FIG. It is perceived as a boundary between the shadow (dark) part and the light (bright) part of the transmitted light. As the means for recognizing the boundary, as shown in (b) of FIG. 5, the illuminance level signal in the measurement area is determined to be higher or lower than the threshold value, or as shown in (c) of FIG. For example, there is a method in which a signal is differentiated and the center value thereof is captured. Here, the coordinates (x, y) of the measurement point (m) positioned by the computer 33 are the X-axis and Y-axis position sensors 12, 1
3 which is coincident with the coordinates of the center of the measuring area on the screen. A deviation amount δ between this and the position of the cutting edge portion εm is calculated as a distance from the center position of the measurement area to the boundary position between the bright portion and the dark portion, and is set as a correction amount. As a result, the actual coordinates of the cutting edge portion εm at the measurement point (m) become the corrected data (x + δ, y), which is the measurement data of the ball end mill 3. The rectangular measurement area at the time of measurement by this image processing is measured so that the actual coordinate shift amount of the measured cutting edge portion εm becomes clear with respect to the calculated coordinate of the measurement point (m). When the angular position of the point (m) with respect to the tool axis is 45 degrees or less, the X-axis direction is the long side and 4
When the angle is 5 degrees or more, the long side is set in the Y-axis direction.

In the case of a ball end mill, each measuring point (1)
(N) is from 0 degrees to 9 with respect to the tool axis for one blade
It is set at equal intervals between 0 degrees, and for example, in the case of measurement every 10 degrees, 10 points are measured up to 0 degree, 10 degrees ... 90 degrees. In the case of the two-blade ball end mill as shown in this embodiment, 21 points are measured at intervals of 10 degrees between -90 degrees and +90 degrees. If you have a large number of blades 1
The measurement is repeated for each blade.

In this way, when the measurement of the cutting edge portion is completed for all the measurement points, the measuring device returns to the origin, and the ball end mill 3 is removed here. The measurement data of the cutting edge portion at each measurement point of the ball end mill 3 obtained as described above is a point group of coordinates.
The point group of these coordinates is calculated in accordance with an arithmetic processing program previously input to the computer 33, the center coordinates of the tip blade portion R of the ball end mill 3 are first calculated by the least square method of the circle, and further, at each measurement point. R of the cutting edge
Calculate various values related to the radius and other shape accuracy of the ball end mill. The various calculation results thus calculated are R
The data is displayed on the GB monitor 35 and, if necessary, printed out by the printer 36.

In the above embodiments, the case where the ball end mill is measured has been described. However, the present invention allows the taper ball end mill to be operated by inputting a predetermined measurement procedure and a calculation processing program into the control / calculation unit in advance. It is also possible to measure the edge shape of a special blade drill.
Further, in this embodiment, the case where the operation for aligning the focus position of the tool microscope with the axis of the rotary tool is manually performed has been described, but this operation can also be automatically performed depending on the measurement procedure program. When using the reference block, it is possible to move it outside the measurement range of the tool microscope simply by moving the XY table, and there is no need to replace it as in the case of the reference center. By incorporating the tool microscope unit, which is the measuring part of the device of the present invention, into the machine tool and connecting the control / calculation part to the computer for controlling the machine tool, the tool blade shape is successively measured during machining to reduce tool wear. It can be a processing system that compensates, and high-precision molding processing is realized.

[0018]

According to the present invention, when measuring the shape of the blade of a rotary tool, the focus position of the tool microscope is first fixed to the axis of the rotary tool, and then the height of the cutting edge at each measurement point is determined. The position coordinates of the cutting edge at each measurement point can be accurately captured because the position of the focus of the microscope is matched by angularly positioning the rotary tool around the axis. Further, since there is no blurring of the image, the measurement can be performed easily and quickly. In the present invention, the detection of the cutting edge of the rotary tool is detected as the maximum point of the image contrast by the TV camera and the image processing device connected to the TV camera, so that an accurate measurement value can be obtained even when the rotary tool has a small diameter. . Further, in the present invention, since each measurement point on the contour line of the blade of the rotary tool is measured by the XY coordinates, a substitution error may occur during the arithmetic processing as compared with the measurement by the R-θ coordinates. In addition, the time required for the arithmetic processing can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory view when a ball end mill is measured by the method of the present invention.

FIG. 2 is a perspective view showing a measuring unit of an apparatus according to an embodiment of the present invention.

FIG. 3 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 4 is a flowchart of a measurement procedure when the measurement is performed by the device of FIGS. 2 and 3.

FIG. 5 is an image recognized by an image processing device during measurement.

FIG. 6 is an explanatory diagram showing a problem of the conventional technique.

[Explanation of symbols]

 1 Tool microscope unit 2a Light source 3 Rotating tool (ball end mill) 4 XY table 19 TV camera (CCD camera) 24 Angle indexing table 30 Image processing device 33 Computer 37 3-axis controller P Optical axis h Height of A axis

Claims (2)

[Claims] 1. An axis line of a rotating tool is arranged in a direction perpendicular to an optical axis of a tool microscope unit having a TV camera for converting an image into an electric signal, and a focus position of the tool microscope unit is first matched with a position of the axis line of the rotating tool. Then, the optical axis of the tool microscope unit is sequentially positioned at a plurality of measurement points on the contour line of the blade of the rotary tool, and the rotary tool is cut at each measurement point by the image processing device connected to the TV camera. The rotary tool is angularly positioned around its axis A so as to match the focus position of the tool microscope unit by detecting the blade, and here, the coordinates of the cutting edge at each measurement point in the X-axis and Y-axis directions are measured, A method for measuring the shape of a blade of a rotary tool, characterized in that the dimension or shape accuracy of the tip of the tool is calculated based on these measured values. 2. A tool microscope unit having a light source, a lens system, and a TV camera for converting an image into an electric signal, and provided with an XY table movable in the X-axis and Y-axis directions on a plane orthogonal to the optical axis thereof. The XY table is provided with an angle indexing table capable of rotating the axis of the rotary tool at right angles to the optical axis and rotating around the axis A by an arbitrary angle, and processes the image signal of the TV camera. An image processing device for detecting a cutting edge of a rotary tool, and a computer for receiving a signal from the image processing device to calculate a numerical value of a blade shape of the rotary tool and issuing a control command for X, Y and A axes according to a predetermined program. A three-axis controller for controlling the movement of the XY table in the X-axis and Y-axis directions and the rotation angle of the angle indexing table according to a control command from a computer. A blade part shape measuring device for rolling tools.