JP3015636B2 - On-machine shape measurement method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-machine shape measuring method and apparatus, and more particularly, to electric discharge machining, cutting, and the like.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-machine shape measuring method and apparatus capable of measuring a deformation of a tool caused by a shape of a workpiece or tool wear in a grinding process or the like on a machine tool without removing the workpiece from the machine tool.

[0002]

2. Description of the Related Art Conventionally, there has been an attempt to measure a machining state such as a shape and a surface property of a workpiece during machining or while machining is stopped and to reflect the measured conditions on machining conditions. Have been. For example, in a machining center or the like, a shape of a workpiece is measured by attaching a touch probe as one of tools for an ATC (Automatic Tool Changer) to a main shaft. Alternatively, the tool is brought into contact with a touch probe mounted on a processing table to measure the degree of chipping or wear of the tool. In addition, Japanese Patent Application Laid-Open No. 62-231310 discloses a technique relating to a position / posture measuring method for measuring the position / posture of a robot arm.

[0003]

However, in the conventional on-machine shape measuring method and apparatus as described above, the tip position of the probe on the NC (numerical control) machine tool and the axial direction thereof are fixed in advance. I was On the other hand, in order to achieve high-accuracy measurement, it was necessary to apply the probe perpendicularly to the surface to be measured. Therefore, for example, when a shape such as a mold is extremely complicated, high-precision measurement has been difficult.

FIG. 8 is an explanatory view showing a shape that cannot be measured by the conventional measuring method and apparatus, and shows an example in which the measurement is difficult by the conventional measuring method. In FIG. 8, 8
Reference numeral 1 denotes a measurement probe, 82a and 82b are objects to be measured, and 83 is a table on which the objects to be measured 82a and 82b are placed. As shown in FIG. 8, the DUTs 82a and 82b
In the case where the upper part has a shape that covers the lower part, there is only a measuring method using an NC machine having five axes. Even if, for example, the tip of the measurement probe 81 has an angle, it is very difficult to guarantee the positional accuracy of the tip of the measurement probe 81, and therefore, it has been difficult to perform highly accurate measurement. Conventionally, it has not been possible to measure the shape of an object to be measured continuously and with high accuracy.

Accordingly, the present invention provides an electric discharge machining, a cutting process,
In grinding, etc., the deformation of the tool caused by the shape of the workpiece or the wear of the tool can be continuously measured with high accuracy on the machine tool without removing the workpiece from the machine tool, even in the case of complicated shapes. It is an object of the present invention to provide an on-machine shape measuring method and apparatus.

[0006]

According to a first aspect of the present invention, there is provided an on-machine shape measuring apparatus, comprising: a boundary surface detecting sensor for detecting a surface of a workpiece mounted on a spindle head or a processing table; A calibration reference polyhedron having a known plane equation disposed on the spindle head and a calibration reference polyhedron, and driving the interface detection sensor to detect three or more planes of the calibration reference polyhedron; ; and a position adjustment means for calibrating the position of the detection sensor, the shape at the output of the position adjustment means based on the position vector of each measurement site by moving the boundary surface detecting sensor may Mitsurusu the plane equation Is to measure.

According to a second aspect of the present invention, there is provided an on-machine shape measuring apparatus which drives a spindle head or a boundary surface detecting sensor for detecting a surface of a workpiece mounted on a machining table, thereby forming the machining table or the spindle head. Each surface arranged above
Plane equation detects three or more sides of the plane of the calibration reference polyhedron is known, the plane equation is the position vector of each measurement site by moving the boundary surface detecting sensor calibration position of the boundary surface detecting sensor Is performed based on satisfying

According to a third aspect of the present invention, there is provided an on-machine shape measuring apparatus, comprising: a boundary surface detecting sensor for detecting a surface of a workpiece held by a robot on a spindle head or a machining table; and the machining table or the spindle head. A calibration reference polyhedron having a known plane equation and having a known polyhedron, and the posture of the robot is changed according to a measurement site, and at least three optimal surfaces of the calibration reference polyhedron are determined for each posture. detects more planes, comprising a position adjustment means for calibrating the position of the boundary surface detecting sensor, a position vector of each measurement site by moving the boundary surface detecting sensor the plane equation that the Mitsurusu The shape is measured based on the output of the position calibrating means based on the above.

According to a fourth aspect of the present invention, there is provided an on-machine shape measuring apparatus, comprising: a boundary surface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table; Arranged plane process
The calibration reference polyhedron whose formula is a known polyhedron, and measuring the position and orientation between the calibration reference polyhedron by driving the boundary surface detection sensor, temperature change, deformation of the machine tool with time change. ; and a deformation estimating means for estimating, in which the position vector of each measurement site by moving the boundary surface detecting sensor measures the shape at the output of the position adjustment means based on Mitsurusu the plane equation .

According to a fifth aspect of the present invention, there is provided an on-machine shape measuring apparatus for driving a spindle head or a boundary surface detection sensor for detecting a surface of a workpiece mounted on a machining table to thereby produce the machining table or the spindle head. Multiple above
The position equation between the calibration reference polyhedron consisting of a known polyhedron and the position and orientation between the calibration polyhedrons is measured, and the temperature change, the deformation of the machine tool accompanying the aging change, and the position vector of each measurement site where the boundary surface detection sensor is moved. There is to estimate based on Mitsurusu the plane equation.

According to a sixth aspect of the present invention, there is provided an on-machine shape measuring apparatus, comprising: a boundary surface detecting sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table; The plane equation provided is a calibration reference polyhedron composed of a known polyhedron, and the boundary surface detection sensor is driven to detect three or more planes of the calibration reference polyhedron, and the boundary surface detection sensor performs calibration of the position of, and and a shape measuring means for measuring the shape of the object to be measured, the position vector of each measurement site by moving the boundary surface detecting sensor based on Mitsurusu the plane equation The shape is measured by the output of the position calibration means.

According to a seventh aspect of the present invention, there is provided an on-machine shape measuring apparatus which drives a spindle head or a boundary surface detection sensor for detecting a surface of a workpiece mounted on a machining table to thereby produce the machining table or the spindle head. The plane arranged above
Equation to detect three or more sides of the plane of the calibration reference polyhedron consisting of known polyhedron, to perform calibration of the position of the boundary surface detecting sensor, a position vector of each measurement site by moving the boundary surface detecting sensor wherein The shape of the object to be measured is measured based on satisfying a plane equation.

According to an eighth aspect of the present invention, there is provided an on-machine shape measuring apparatus comprising: a boundary surface detecting sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table; The plane equation provided is a calibration reference polyhedron composed of a known polyhedron, and the boundary surface detection sensor is driven to detect three or more planes of the calibration reference polyhedron, and the boundary surface detection sensor Position calibration means for calibrating the position, and continuously driving the boundary surface detection sensor so that the output voltage of the boundary surface detection sensor is constant or within a predetermined range, and moved the boundary surface detection sensor. in which the position vector of each measurement site; and a shape measuring means for measuring the shape of the object to be measured based on Mitsurusu the plane equation.

According to a ninth aspect of the present invention, in the on-machine shape measuring apparatus, the shape measuring means determines a distance between the measurement points based on the horizontal and vertical movement amounts of the boundary surface detection sensor when measuring the shape of the object to be measured. An angle that is an elevation angle or a depression angle is calculated, and when the angle exceeds a predetermined range, the direction of the boundary surface detection sensor with respect to the object to be measured is changed as necessary, and then the boundary surface detection is performed by the position calibration unit. A new calibration of the sensor position is performed.

[0015]

According to the first and second aspects of the present invention, a surface of a workpiece mounted on a spindle head or a machining table is provided.
A known polyhedron disposed on the machining table or the spindle head by driving a boundary surface detection sensor for detecting
Since three or more planes of the calibration reference polyhedron are detected and the position of the boundary surface detection sensor is calibrated, the fact that the position vector of the boundary surface detection sensor satisfies a known plane equation is used. To determine the exact position of the boundary surface detection sensor,
Calibration of the position of the fixed part is possible.

According to the third aspect of the present invention, the surface of the workpiece is detected by the robot on the spindle head or the processing table.
Grasps the interface detection sensor output, is changed according to the posture of the robot to the measurement site, known polyhedron arranged on the machining table or the spindle head with respect to each position
Optimum surface of calibration polyhedron consisting of at least 3 or more
Since the upper plane is detected and the position of the boundary surface detection sensor is calibrated, by utilizing that the position vector of the boundary surface detection sensor satisfies a known plane equation for each posture of the robot. The accurate position of the boundary detection sensor can be determined and the position can be calibrated.

In the inventions of claims 4 and 5,
Workpiece mounted on spindle head or machining table
A plurality of known surfaces provided on the machining table or the spindle head by driving a boundary surface detection sensor that detects the surface of
It measures the position and orientation between the calibration reference polyhedrons composed of polyhedrons, and estimates the deformation of the machine tool due to temperature changes and changes over time. Utilizing that the position vector satisfies the known plane equation, it is possible to estimate the deformation of the machine tool due to temperature change and temporal change.

In the invention of claims 6 and 7,
Workpiece mounted on spindle head or machining table
By driving a boundary surface detection sensor that detects the surface of the workpiece, the known multi- purpose sensor disposed on the machining table or the spindle head is driven.
Since the boundary surface of each surface of the calibration reference polyhedron composed of a planar body is detected, the position of the boundary surface detection sensor is calibrated, and the shape of the measured object is measured, the position vector of the boundary surface detection sensor is by utilizing the fact that satisfies the known plane equation, calculated the exact position of the boundary surface detecting sensor, the boundary
Calibration can be performed based on each measurement site to which the interface detection sensor has been moved, and the shape of the measured object can be measured.

According to the eighth aspect of the present invention, a surface of a workpiece mounted on a spindle head or a processing table is detected.
That drives the boundary detection sensor the detects the machining table or boundary surface of each surface of the school <br/> Tadashiyo reference polyhedron consisting of known polyhedron arranged on the spindle head, the boundary surface detecting Since the position of the sensor is calibrated and the shape of the object to be measured is measured by continuously driving the interface detection sensor so that the output voltage is constant or within a predetermined range, the position of the interface detection sensor is determined. Utilizing that the vector satisfies the known plane equation, the exact position of the boundary surface detection sensor is determined, and each measurement site where the boundary surface detection sensor is moved is determined.
Calibration can be performed on the basis of this, and the shape of the measured object can be measured.

According to a ninth aspect of the present invention, in addition to the operation of the eighth aspect, the elevation angle or the elevation angle between the measurement points is determined based on the horizontal and vertical movement amounts of the boundary surface detection sensor when measuring the shape of the object to be measured. Calculate an angle which is a depression angle, and when the angle exceeds a predetermined range, after changing the direction of the boundary surface detection sensor with respect to the object to be measured as necessary, perform a new calibration of the position of the boundary surface detection sensor. Because it's what you do
By utilizing the fact that the position vector of the boundary detection sensor satisfies the known plane equation, an accurate position of the boundary detection sensor is obtained, and the boundary detection sensor becomes necessary when the driving angle exceeds a predetermined range. Each measurement part whose direction with respect to the object to be measured can be changed accordingly and the boundary surface detection sensor has been moved
Can be calibrated based on the above, and the shape of the measured object can be measured.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific embodiments. <Embodiment 1> FIG. 1 is an explanatory view showing an on-machine shape measuring method and apparatus according to a first embodiment of the present invention. This figure shows a state in which a commercially available roughness measuring stylus is used as a shape measuring probe to measure the change in shape of an electrode and a workpiece in electric discharge machining. In FIG. 1, 1 is an electrode for electric discharge machining, 2 is a workpiece, 3 is a spindle, 4 is a machining table on which the workpiece 2 is mounted, 5 is a stylus attached to the spindle 3 side, and 6 is a stylus. 5 is a flexible holder for holding the stylus 7; 7 is a flexible holder for holding the stylus 7; 9 is a reference polyhedron for calibration mounted on the spindle 3 side; Plate holding the reference polyhedron 9 for use and having an orthogonal reference plane; 11, a reference polyhedron for calibration attached to the processing table 4; 12, a plate holding the reference polyhedron 11 for calibration and having an orthogonal reference plane; An NC controller 14 is a demodulation circuit that demodulates the signals of the styluses 5 and 7, and 15 is a computer that processes the signals of the demodulation circuit 14. In this embodiment, the calibration reference polyhedron 9 having a large number of planes on the main shaft 3 of the processing machine main body and the processing table 4,
11 are provided. These calibration reference polyhedrons 9,
Each surface of 11 is precisely measured in advance, and the plate 1
Surface equations for 0,12 orthogonal reference planes have been determined. The plates 10 and 12 are set so as to be parallel to the machine coordinate system. The measurement styluses 5 and 7 are driven by the NC control device 13 together with the processing table 4 or the main shaft 3. Then, the coordinates of the X, Y and Z axes are sent to the computer 15 when the tips of the measuring styluses 5 and 7 functioning as probes come into contact with the surface to be measured.
The operation of the computer 15 can be replaced by the NC control device 13.

Next, the principle of measurement will be described. FIG. 2 is a principle diagram showing an on-machine shape measuring method and apparatus according to the first embodiment of the present invention. In FIG. 2, 21 is the machine origin,
Reference numeral 22 denotes one point on the main shaft 3, and reference numeral 23 denotes a tip position of the stylus 5. As shown in FIG. 2, the NC controller 13 of the electric discharge machine
Is the mechanical origin 2 which is the origin for the NC control of one point 22 (the point where measurement is performed) on the spindle 3.
Represents the displacement from 1. When this is defined as a vector r and the relative position of the stylus tip position 23 attached to the spindle 3 to one point 22 on the spindle 3 is defined as a vector r ＾, the position of the needle tip as a measurement point (stylus tip position 23) is It is represented by the sum of vectors r + r ＾. Here, the vector r ＾ changes according to the position and orientation of the stylus 5. Once the orientation of the stylus 5 has been determined to recognize r ＾ in each orientation, the stylus tip is placed on each of the three surfaces by bringing the stylus tip into contact with three different planes for which the equations for each surface are known. And the following general formula is obtained. (Ni / di) (r + r ＾) = 1 (i = 1, 2, 3) where r = (x, y, z) r ＾ = (x ＾, y ＾, z ＾) R = (X, Y) , Z) = (x + x ＾, y + y ＾, z + z ＾) αi X + βi Y + γi Z = dini = (αi, βi, γi), and the vector R is represented by a function of the vector r + r ＾, and d
i is the measurement position i = 1, 2, 3, is a constant that determines the position of the plane in the case of identifying .... ni is the orientation of the plane
This is the vector shown . Therefore, r ＾ at a predetermined position i can be obtained by simultaneously solving this equation.
That is, if the plane di is specified, the general expression is ( ni / di ).
-The inner product of (r + r ＾) = 1 and the vector. here.
The vector ni is a vector perpendicular to the plane specifying the measurement position i.

(Equation 1) From the above or wherein the vertical position base of the known three faces of the polyhedron
(Α1, β1, γ1), (α2, β2, γ2),
(Α3, β3, γ3) and each point (X
1, Y1, Z1), (X2, Y2, Z2), (X3, Y
3, Z3) , the equation of the plane is: α1 (X1 + x ＾) + β1 (Y1 + y ＾) + γ1 (Z1 + z ＾) = d α2 (X2 + x ＾) + β2 (Y2 + y ＾) + γ2 (Z2 + z ＾) ) = D α3 (X3 + x ＾) + β3 (Y3 + y ＾) + γ3 (Z3 + z ＾) = d , and the vector r ＾ can be obtained from the above three equations .

[0023] Here, the reference plane choose the best surface by the attitude of the stylus 5 to be used, the range from the pre-calibrated calibration reference polyhedron, the needle of the stylus 5 is 20 degrees from the vertical as the best plan d Is selected. If the needle of the stylus 5 has an angle greater than the range of 20 degrees from the vertical, accurate measurement becomes difficult.
The reference polyhedron for calibration is attached to the electrode surface plate side and the processing table side, respectively, and calibration is performed respectively. It is necessary to select the optimal surface from this calibration reference polyhedron and perform calibration.
This is performed every time the posture of the stylus 5 is changed.

In particular, in electric discharge machining, since the shape of the electrode is transferred to the workpiece, the accuracy of the shape of the electrode is important. However, as in the case of cutting, the electrode, which is a tool, is consumed as the machining proceeds. Recently, machining with an electrode weight consumption ratio (electrode consumption weight / workpiece processing weight) of about 0.5% has been realized due to advances in electric discharge machining power supplies and the like. This is a problem of precision machining. FIG. 3 is a characteristic diagram showing measurement results by the on-machine shape measuring method and apparatus according to the first embodiment of the present invention. FIG. 3 shows an enlarged view of the consumption shape at the corner of the copper electrode having a diameter of 10 mm. In FIG. 3, 51, 52, 5
3, 54 and 55 are electrodes at the corners of the electrodes with the passage of time.
It is the measurement result which measured the change of the state of exhaustion . Specifically, 51 is the state of the electrode before electrical discharge machining, 52 is 0.5 mm electrical discharge machining, 53 is 1 mm electrical processing, and 54 is 2
55 mm indicates the state of electrode consumption after 3 mm processing. The electrode corners having a radius of several μm or less before the electric discharge machining shown in FIG .
After 2 mm processing, the state of electrode consumption after 55 3 mm processing
Thus, it can be seen that the shape of the electrode changes to a radius of several tens of μm. Thus, the shape of the middle electrode and workpiece machining to monitor with high precision is not possible unless a measurement method as in the present embodiment.

Further, since the stylus for roughness measurement is used as a probe in the apparatus of this embodiment, a relative shape profile at each measurement site can be obtained by continuously scanning the stylus position according to the NC command. Can be Therefore, in this case, the shape measurement can be easily performed while measuring the surface roughness, although locally. And more than one
When shape measurements such as surface roughness were performed continuously and locally
The geometric measurement of each part is several μm
It can be measured within a margin of error.

The method described here can also be implemented using a non-contact probe or a touch probe such as an optical probe. Also, a simple needle or a small ball made of a conductive material is attached in place of the styluses 5 and 7, and the reference polyhedrons 9 and 11 for calibration are also made of a conductive material and detect electrical contact. Also obtains the same effect. Thus Engineering
A known sensor can be used as the boundary surface detection sensor for detecting the crop surface . In any case, the tip position can be obtained by using the calibration reference polyhedron as in this embodiment.

It should be noted that the method of this embodiment reduces electrode consumption,
It is also possible to measure the processing amount of the workpiece and, for example, correct the feed amount corresponding to the consumed amount by a known method, or change the processing conditions by a known method.

Further, the flexible holders 6, 8 can be replaced with articulated robots. In this case, the posture of the robot can be automatically changed according to the measurement site, and automation is further promoted. The reference polyhedrons 9 and 11 for calibration are attached to the plates 10 and 12, respectively, and may be arranged on the NC processing table 4 and the spindle 3 so that the orthogonal coordinate planes of the plates 10 and 12 are parallel to the machine origin coordinates. , And the application of the present embodiment is also facilitated because there is almost no restriction on the installation location.

Of course, the reference polyhedron for calibration is
Even if it is used by directly fixing it to the main shaft 3, the effect is not impaired at all. Further, the boundary surface detection sensor can be replaced by a tool changing device like a tool. In this way, the sensor can be mounted only when necessary, so that interference with a tool or a workpiece can be avoided. In this case, there is an effect that the measurement can be performed without any problem even if there is a positional deviation at the time of tool change.

The method of this embodiment can be applied to a three-dimensional coordinate measuring device as it is. By fixing the probe of the three-dimensional coordinate measuring device in the direction corresponding to the shape of the workpiece and calibrating it using the calibration reference polyhedron, it is possible to measure workpieces with complicated shapes with high accuracy. is there.

As described above, the on-machine shape measuring apparatus of the present embodiment includes the styluses 5 and 7 functioning as boundary surface detection sensors mounted on the spindle 3 head and the processing table 4, and
The reference polyhedron for calibration 9, 1 having three or more planes disposed on the processing table 4 or the main spindle 3 head
1 and the styluses 5 and 7 (boundary surface detection sensors) are driven to detect the boundary surfaces of the respective surfaces of the calibration reference polyhedrons 9 and 11 and the positions of the styluses 5 and 7 (boundary surface detection sensors) are determined. An NC control device 13 (position calibration means) for performing calibration is provided.

The on-machine shape measuring method of this embodiment is as follows.
By driving the styluses 5 and 7 (boundary surface detection sensors) mounted on the spindle 3 head or the machining table 4, the stylus has three or more planes disposed on the machining table 4 or the spindle 3 head. The interface between the surfaces of the calibration reference polyhedrons 9 and 11 is detected, and the positions of the styluses 5 and 7 (interface detection sensors) are calibrated.

That is, in the shape measuring apparatus according to the present embodiment, it is attached to the flexible holder manually or automatically when a shape model is given in advance according to the position and inclination of the measured part. The position and posture of the probe (stylus 5, 7) are adjusted and installed. In such a case, probe (stylus 5, 7)
It is extremely difficult to accurately set the tip position of the probe with respect to the machine origin, so the probe (stylus 5, stylus 5,
7) It is necessary to calibrate the position of the tip. In this calibration, a probe (stylus 5, stylus 5,
7) Although the tip position can be measured, it is difficult to automatically recognize a three-dimensional position.

Therefore, in the calibration method in the present embodiment, the calibration is performed using calibration reference polyhedrons 9 and 11 which are an aggregate of a large number of surfaces which are precisely measured in advance and the equations of each surface are known. That is, three or more surfaces corresponding to the posture of the probe (stylus 5, 7) are selected from these surfaces, and the tip of the probe (stylus 5, 7) is brought into contact with each surface. Since the position vector of the tip of the probe (stylus 5, 7) satisfies the known plane equations that are in contact, the position of the tip can be determined by solving these equations.

In this manner, if the calibration reference polyhedron has a surface required for calibration at any position or orientation, the tip position is determined, and a surface to be measured having any inclination can be measured.

Therefore, utilizing the fact that the position vectors of the styluses 5 and 7 (boundary surface detection sensors) satisfy the known plane equation, the exact positions of the styluses 5 and 7 (boundary surface detection sensors) are determined. Calibrate the position. As a result, by using the method and the apparatus of the present embodiment, it is possible to remove the deformation of the tool caused by the shape of the workpiece, tool wear, etc. in the electric discharge machining, cutting, grinding, etc., from the machine tool. No, even for complex shapes,
Measurements can be made with high accuracy on machine tools.

In particular, a robot holding styluses 5 and 7 (boundary surface detection sensors) is installed on the machining table 4 or the main spindle 3 head, and the posture of the robot is automatically changed in accordance with the measurement site to change each position. If the positions of the styluses 5 and 7 (boundary surface detection sensors) are calibrated by selecting at least three optimal surfaces of the calibration reference polyhedrons 9 and 11 with respect to the posture and detecting the boundary surface, more automation can be achieved. Can be promoted.

When applied to a three-dimensional coordinate measuring device,
The stylus 5 or 7 (interface detection sensor) is driven to detect the interface between the respective surfaces of the calibration reference polyhedron having three or more planes disposed on the machining table 4 or the spindle 3 head. In addition, since the positions of the styluses 5 and 7 (boundary surface detection sensors) are calibrated and the shape of the object to be measured can be measured, even a workpiece having a complicated three-dimensional shape can be measured with high accuracy, and more accurate processing can be performed. Can be.

<Embodiment 2> FIG. 4 is an explanatory view showing a method of measuring table deformation by an on-machine shape measuring method and apparatus according to a second embodiment of the present invention. This figure shows a method of setting a plurality of reference polyhedrons for calibration on a processing table and detecting a posture between the reference polyhedrons for calibration, thereby obtaining a deformation of the processing table accompanying a temperature change or the like. In addition,
In the present embodiment, the same components as those of the above-described first embodiment or those having corresponding parts are denoted by the same reference numerals and symbols, and detailed description thereof will be omitted. In FIG.
Reference numeral 71 denotes a first calibration reference polyhedron, reference numeral 72 denotes a second calibration reference polyhedron, and both the first calibration reference polyhedron 71 and the second calibration reference polyhedron 72 are arranged on the same processing table 4. Has been established. Then, r ＾ is determined by the first calibration reference polyhedron 71. At the same time, r ＾ ′ is obtained from the second calibration reference polyhedron. r ＾ −r ＾ ′ is the first calibration reference polyhedron 71 and the second calibration reference polyhedron 7
The difference between r ２−r ＾ ′ is obtained by appropriately measuring the calibration reference polyhedrons 71 and 72 with the progress of processing.
, It is determined that the processing table 4 has been deformed. Therefore, the deformation of the processing table 4 is obtained, the deformation of the machine tool such as the processing table 4 due to the temperature change and the aging change is estimated, and the NC command for compensating the deformation is generated to perform the processing. Note that the method of obtaining r ＾ and r た 'has been described in the first embodiment, and a description thereof will be omitted.

As described above, the on-machine shape measuring apparatus according to the present embodiment is provided on the same processing table 4 as the interface detecting sensor constituted by the stylus 5 mounted on the main spindle 3 head. First and second calibration reference polyhedrons 7
1 and 72 and the boundary surface detection sensor to drive and measure the position and orientation between the first and second calibration reference polyhedrons 71 and 72. And a deformation estimating means comprising an NC control device 13 for estimating the deformation of the machine tool.

The on-machine shape measuring method of this embodiment is as follows.
The stylus 5 (interface detection sensor) mounted on the spindle 3 head is driven to measure the position and orientation between the first and second calibration reference polyhedrons 71 and 72 disposed on the processing table 4. Then, the deformation of the machine tool such as the processing table 4 due to the temperature change and the aging change is estimated.

Therefore, utilizing the fact that the position vector of the stylus 5 (boundary surface detecting sensor) with respect to the first and second calibration reference polyhedrons 71 and 72 satisfies a known plane equation, the machining of the machining table 4 or the like is performed. Deformation due to temperature change and time-dependent change of the machine can be estimated. As a result, by using the method and the apparatus of the present embodiment, it is possible to measure the deformation of the processing table 4 or the like with high accuracy without removing the workpiece from the machine tool in electric discharge machining, cutting, grinding, or the like. Becomes possible.

In the second embodiment, the case where two calibration reference polyhedrons of the first calibration reference polyhedron 71 and the second calibration reference polyhedron 72 are arranged on the processing table 4 has been described. The number of the reference polyhedrons for calibration may be further increased. By appropriately considering the arrangement position, it is possible to estimate a three-dimensional deformation of the processing table 4. Further, a plurality of reference polyhedrons for calibration may be arranged on the main shaft 3, and in this case, it can be used to estimate the deformation of the main shaft 3.

<Embodiment 3> FIG. 5 is an explanatory view showing the shape measurement of an object to be measured by an on-machine shape measuring method and apparatus according to a third embodiment of the present invention. This figure shows a method of measuring the shape of the object by driving the stylus on the object. In FIG. 5, reference numeral 25 denotes an object to be measured, 26 denotes a stylus, and stylus 27 denotes a position where the stylus 26 has moved by scanning in the X-axis direction in measurement.

Next, a measuring method will be described. Since this apparatus uses a stylus for roughness measurement as a probe, the stylus position is continuously scanned by the NC command, and a relative shape profile at each measurement site can be obtained. By driving the stylus in the vertical direction (Z-axis direction) such that the output voltage of the stylus is constant or within a predetermined range during this scanning, highly accurate measurement on the order of μm is possible.

When the stylus 26 comes into contact with the DUT 25, a signal corresponding to the pressure applied to the stylus 26 is obtained as an output voltage by the demodulation circuit 28. In the case of FIG. 5, when scanning is performed in the + X direction (X-axis positive direction), the pressure applied to the stylus 26 increases, and the output voltage increases. It is desirable to measure the stylus 26 so that the output voltage is within a predetermined range in order to obtain accuracy. Accordingly, the shape is continuously measured with high accuracy by moving the output signal upward in the vertical direction (Z-axis direction) when the output signal increases and downward in the vertical direction (Z-axis direction) when the output voltage decreases. be able to.

Embodiment 4 FIG. 6 is an explanatory view showing the shape measurement of an object to be measured by an on-machine shape measuring method and apparatus according to a fourth embodiment of the present invention. This figure shows a method of measuring the shape of the object by driving the stylus on the object. The angle between the measurement points is calculated from the amount of movement in the horizontal direction (X-axis and Y-axis directions) and the vertical direction (Z-axis direction) at the time of shape measurement, and when the angle exceeds a predetermined range, the angle is calculated again. A method for calibrating the position of a stylus (boundary surface detection sensor) using a calibration reference polyhedron will be described. In FIG.
Reference numeral 30 denotes an object to be measured, and 31 denotes a stylus.

Next, a measuring method will be described. The angle of the measurement point can be determined from the amount of movement in the horizontal direction (X-axis and Y-axis directions) and the amount of movement in the vertical direction (Z-axis direction) when the stylus position is continuously scanned by the NC command. In order to perform accurate measurement, it is desirable to calibrate on the surface of the calibration reference polyhedron having an angle corresponding to the angle of the measurement point. Therefore,
If the angle of the measurement point deviates, for example, by 20 degrees from the angle of the surface on which the stylus has been calibrated, the stylus position is again calibrated on the surface of the calibration reference polyhedron having an angle close to the angle of the measurement point.

FIG. 7 shows the shape measurement of an object to be measured by the on-machine shape measuring method and apparatus according to the fourth embodiment of FIG.
It is a principle diagram of the method of calculating the angle of the measurement point. In FIG. 7, reference numeral 35 denotes an object to be measured, 36 denotes a stylus, and 37 denotes a position where the stylus 36 has moved by scanning in the X-axis direction in measurement. 38 is a movement amount (distance) operated in the X-axis direction, 39
Is the amount of movement (distance) in the Z-axis direction, and 40 is the angle of the measurement point.

As shown in the fourth embodiment of FIG.
Assuming that movement amounts 38 and 39 in the X-axis direction and the Z-axis direction when measurement is performed while moving the stylus 36 to an appropriate position in the Z-axis direction along with scanning in the axial direction are X and Z, respectively, an angle 40 of a measurement point Is determined as tan ^-1 (Z / X).

Further, when performing high-accuracy measurement, the stylus angle is changed when the angle of the measurement point deviates from a predetermined range. For high-accuracy measurement, it is necessary that the stylus needle is at an angle in the range of 20 degrees from the vertical, and if the angle is larger than that, it becomes difficult to perform accurate measurement. Therefore, the angle of the stylus is changed by adjusting the angle of the measurement point, and then calibration is performed using the calibration reference polyhedron.

[0052]

As described above, the on-machine shape measuring method and apparatus according to the first and second aspects of the present invention include a boundary surface detecting sensor, a reference polyhedron for calibration, and a position calibrating means. By driving a boundary surface detection sensor mounted on the spindle head or the processing table , three or more planes of the reference polyhedron for calibration disposed on the processing table or the spindle head
By detecting the position of the boundary surface detection sensor and performing calibration of the position of the boundary surface detection sensor, using the fact that the position vector of the boundary surface detection sensor satisfies a known plane equation, the accurate position of the boundary surface detection sensor is obtained, and Since the position can be calibrated, in EDM, cutting, grinding, etc., the deformation of the tool caused by the shape of the workpiece or tool wear, etc. can be performed without removing the workpiece from the machine tool when the workpiece has a complicated shape. However, it can be measured with high accuracy on a machine tool.

According to a third aspect of the present invention, there is provided an on-machine shape measuring apparatus comprising a boundary surface detecting sensor, a reference polyhedron for calibration, and a position correcting means, wherein the robot detects the boundary surface detecting sensor on a spindle head or a processing table. Hold the robot and change the posture of the robot according to the measurement site. For each posture, a reference polyhedron for calibration placed on the machining table or spindle head
By detecting at least three or more planes and calibrating the position of the boundary detection sensor, the position vector of the boundary detection sensor satisfies a known plane equation for each posture of the robot. Therefore, since the accurate position of the boundary surface detection sensor can be obtained and the position can be calibrated, automation can be further promoted.

According to a fourth aspect of the present invention, there is provided an on-machine shape measuring method and apparatus comprising a boundary surface detecting sensor, a reference polyhedron for calibration, and deformation estimating means, and mounted on a spindle head or a machining table. Driven boundary surface detection sensor to measure the position and orientation between the calibration reference polyhedrons arranged on the machining table or the spindle head, and to detect the deformation of the machine tool due to temperature change and aging. By using the fact that the position vector of the boundary surface detection sensor with respect to a plurality of calibration reference polyhedrons satisfies the known plane equation, it is possible to estimate the deformation of the machine tool due to temperature change and temporal change. It is possible to measure the deformation of a machine tool such as a machining table with high accuracy on a machine tool without removing the workpiece from the machine tool in EDM, cutting, and grinding. To become.

An on-machine shape measuring method and apparatus according to the sixth and seventh aspects of the present invention include a boundary surface detecting sensor, a reference polyhedron for calibration, and a shape measuring means, and are mounted on a spindle head or a processing table. Drive the specified boundary surface detection sensor to set the calibration installed on the machining table or spindle head.
By detecting at least three planes of the reference polyhedron, calibrating the position of the boundary detection sensor, and measuring the shape of the object to be measured, the position vector of the boundary detection sensor satisfies a known plane equation. By using this method, the accurate position of the boundary surface detection sensor can be determined, the position can be calibrated, and the shape of the workpiece can be measured. Therefore, even a workpiece with a complicated three-dimensional shape can be measured with high accuracy. , More precise processing is possible.

An on-machine shape measuring apparatus according to an eighth aspect of the present invention includes a boundary surface detecting sensor, a reference polyhedron for calibration, a position calibrating means, and a shape measuring means, and is mounted on a spindle head or a processing table. Drive the boundary detection sensor
Calibration base located on the machining table or spindle head
Detects at least three or more planes of the quasi-polyhedron, calibrates the position of the boundary surface detection sensor, and drives the boundary surface detection sensor continuously so that its output voltage is constant or within a predetermined range, and By measuring the shape of the sensor, the accurate position of the boundary surface detection sensor can be obtained by using the fact that the position vector of the boundary surface detection sensor satisfies the known plane equation, and the position can be calibrated. In machining, cutting, grinding, etc., the deformation of the tool caused by the shape of the workpiece or tool wear can be performed with high precision on the machine tool without removing the workpiece from the machine tool. Can be measured.

According to the ninth aspect of the present invention, in addition to the effect of the eighth aspect, in addition to the effect of the eighth aspect, the on-machine shape measuring device measures the measuring point based on the horizontal and vertical movement amounts of the boundary surface detection sensor when measuring the shape of the workpiece. Calculate the angle between the elevation angle and the depression angle, and when the angle exceeds a predetermined range, change the direction of the boundary surface detection sensor with respect to the object to be measured as necessary, and then recalibrate the position of the boundary surface detection sensor. In EDM, cutting, grinding, etc., the deformation of the tool caused by the shape of the workpiece or tool wear can be performed without removing the workpiece from the machine tool, even if the workpiece has a complicated shape. It can be measured with high precision on a machine.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an on-machine shape measuring method and apparatus according to a first embodiment of the present invention.

FIG. 2 is a principle diagram showing an on-machine shape measuring method and apparatus according to a first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing an example of a measurement result obtained by the on-machine shape measuring method and apparatus according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a table deformation measuring method by an on-machine shape measuring method and apparatus according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an on-machine shape measuring method and apparatus according to a third embodiment of the present invention.

FIG. 6 is an explanatory view showing an on-machine shape measuring method and apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a principle view showing an on-machine shape measuring method and apparatus according to a fourth embodiment of the present invention.

FIG. 8 is an explanatory view showing a shape that could not be measured by a conventional measuring method and apparatus.

[Explanation of symbols]

 3 Spindle 4 Processing table 5, 7 Stylus 9, 11 Reference polyhedron for calibration 13 NC controller 15 Computer

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Akihiro Goto 5-1-1 Yada Minami, Higashi-ku, Nagoya City, Aichi Prefecture Mitsubishi Electric Corporation Nagoya Works (56) References JP-A-4-63664 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23P 23/00 B23Q 17/00 B23Q 17/20

Claims (9)

(57) [Claims] An interface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table; and a boundary surface sensor disposed on the machining table or the spindle head.
A reference polyhedron for calibration consisting of a polyhedron having a known plane equation; and a position for driving the interface detection sensor to detect three or more planes of the reference polyhedron for calibration and for calibrating the position of the interface detection sensor. ; and a calibration means, aircraft position vector of each measurement site by moving the boundary surface detecting sensor is characterized in that for measuring the shape at the output of the position adjustment means based on Mitsurusu the plane equation Upper shape measuring device. 2. A boundary surface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table is driven to calculate a plane equation of each surface disposed on the machining table or the spindle head. detects 3 or more sides of the plane of a known calibration reference polyhedron, the boundary position vector of each measurement site by moving the boundary surface detecting sensor calibration position detection sensor score fully the plane equation and An on-machine shape measurement method characterized in that the method is performed based on the following. 3. A boundary surface detection sensor for detecting a surface of a workpiece gripped by a robot on a spindle head or a machining table, and provided on the machining table or the spindle head.
A calibration reference polyhedron consisting of a polyhedron whose plane equation is known, and changing the posture of the robot in accordance with the measurement site, and detecting at least three or more planes as the optimum surface of the calibration reference polyhedron for each posture. the to and a position adjustment means for calibrating the position of the boundary surface detecting sensor, the boundary surface of each measurement site moving the sensor position vector is the position adjustment means based on Mitsurusu the plane equation An on-machine shape measuring device for measuring a shape with the output of a computer. 4. A boundary surface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table, and a polyhedron having a plurality of plane equations provided on the machining table or the spindle head and having a known plane equation. A reference polyhedron for calibration, and a deformation estimating means for driving the boundary surface detection sensor to measure a position and orientation between the reference polyhedrons for calibration, and for estimating a temperature change and a deformation of the machine tool due to a change with time. comprising on-press shape measuring apparatus characterized by measuring the shape at the output of the position adjustment means based on the position vector of each measurement site by moving the boundary surface detecting sensor may Mitsurusu the plane equation . 5. A driving method for a boundary surface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table, wherein a plurality of plane equations provided on the machining table or the spindle head are known. the position and orientation between the calibration reference polyhedron consisting of polyhedral measured, temperature changes, the position vector of each measurement site the deformation accompanying the machine tool to change over time moving the boundary surface detecting sensor of the plane equation An on-machine shape measurement method characterized by estimating based on filling. 6. A boundary surface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table, and provided on the machining table or the spindle head.
A calibration reference polyhedron consisting of a polyhedron with a known plane equation, and detecting three or more planes of the calibration reference polyhedron by driving the boundary detection sensor, calibrating the position of the boundary detection sensor, ; and a shape measuring means for measuring the shape of the object to be measured, the shape at the output of the position adjustment means based on the position vector of each measurement site by moving the boundary surface detecting sensor may Mitsurusu the plane equation An on-machine shape measuring device for measuring a shape. 7. A polyhedron having a known plane equation disposed on the machining table or the spindle head by driving a boundary surface detection sensor for detecting a surface of a workpiece mounted on the spindle head or the machining table. detects 3 or more sides of the plane of the calibration reference polyhedron consisting performs calibration of the position of the boundary surface detecting sensor, fully to the position vector is the plane equation of each measurement site by moving the boundary surface detecting sensor Measuring the shape of the object to be measured based on the above. 8. A boundary surface detection sensor for detecting a surface of a workpiece mounted on a spindle head or a machining table, and provided on the machining table or the spindle head.
A reference polyhedron for calibration consisting of a polyhedron having a known plane equation; and a position for driving the interface detection sensor to detect three or more planes of the reference polyhedron for calibration and for calibrating the position of the interface detection sensor. Calibration means, the boundary surface detection sensor is continuously driven so that the output voltage of the boundary surface detection sensor is constant or in a predetermined range, and the position vector of each measurement site that has moved the boundary surface detection sensor is machine shape measuring apparatus characterized by comprising a shape measuring means for measuring the shape of the object to be measured based on the plane equation that Mitsurusu. 9. The shape measuring means calculates an angle, which is an elevation angle or a depression angle, between measurement points from the horizontal and vertical movement amounts of the boundary surface detection sensor when measuring the shape of the object to be measured. When the angle exceeds a predetermined range, the orientation of the boundary surface detection sensor with respect to the object to be measured is changed as necessary, and then the position calibration unit performs a new calibration of the position of the boundary surface detection sensor. 9. The on-machine shape measuring apparatus according to claim 8, wherein: