JPH0560543A - Device for three-dimensional comparison and measurement - Google Patents

Abstract

PURPOSE:To promptly determine whether a subject to be measured is good or bad and to maintain high accuracy against changes in environmental temperature by comparing with tolerance a subtraction value obtained by comparison of data on a master measured and stored in advance with data on measurement of each work. CONSTITUTION:A multiaxis controller 12 comprises a three-axis servo driver 16, a CPU 17, a ROM 18, a RAM 19, an interface 20, a power source portion 21 and the like and required data are input from a teaching box 22 and stored in the controller 12. The dimensional tolerance of each measuring point is input from the tolerance setting portion 49 of a control board 36 according to data on the size measurement of a master and to a specified tolerance value. A predetermined measuring point of a work corresponding to the measuring point of the master is measured and data on measurements obtained are compared with the reference data of the master and arithmetic is performed to calculate a value obtained by subtraction between those data and the value is compared with preset dimensional tolerance to determine whether the value is within the tolerance and display the result, thus determining whether the work is good or bad.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention compares and calculates the measured data of a master, which is measured and stored in advance, with the measured data of each work, and calculates the subtracted value and a preset tolerance. Comparison, judgment, and measurement In the comparative measurement method that judges the quality of the work, the temperature change during measurement of each work is detected or predicted, the coordinate value of the master is measured again by the command, and the stored reference data The present invention relates to a three-dimensional comparative measuring device having a temperature calibration function that updates

[0002]

2. Description of the Related Art Conventionally, various three-dimensional measuring machines have been known, and for example, there are measuring devices as described below. First, while moving the probe equipped in the measuring device main body three-dimensionally with respect to the measurement object held on the measuring table, the probe probe is applied to a predetermined measurement point of the measurement object. I will contact you. Next, the relative movement amount between the measurement point of the measurement object and the probe probe at the time of this contact is detected and data processing is performed, thereby measuring the shape or dimension of the measurement object.

The apparatus having the above-mentioned configuration is for collecting three-dimensional absolute value data, and an apparatus in which the absolute value data and reference data are compared to judge the quality of the measured object is also considered. However, the reference data in this case is a numerical value shown in the manufacturing drawing of the measurement object, for example, data under a predetermined reference temperature condition such as 20 ° ± 2 ° C.

[0004]

According to the conventional configuration,
An ordinary three-dimensional measuring device measures the absolute value of a measuring object three-dimensionally, and the quality of the measuring object cannot be promptly judged from only this data. Further, in order to accurately measure the three-dimensional absolute dimensions of the measurement object, a precise movement mechanism combining a gas slide, a permanent magnet, etc. is required as a movement mechanism of three axes orthogonal to each other, and the probe In order to smoothly move the sliders with high accuracy, it is necessary to rationally integrate slider mechanisms each having a high degree of rigidity and a structure that is resistant to thermal deformation. However, because of this, the mass of the moving mechanism becomes large, and the amount of inertia also increases accordingly, and there is a problem that speedy movement and the constant pressure followability of the probe stylus with respect to the measuring point conflict with each other.

Further, in the case of an apparatus which not only simply measures the three-dimensional absolute value data but also compares it with the reference data to judge the quality of the object to be measured, it is a fixed data obtained from the manufacturing drawing as the reference data. Since I am using a numerical value,
If the environmental temperature of the measurement work changes, the comparative measurement accuracy will decrease. That is, when the environmental temperature at the time of measurement changes, the temperature of the measurement object also changes, so the data obtained by this measurement differs from the reference data in the comparison conditions, and the measurement data is corrected according to the temperature change. Or, it is necessary to correct the reference data.

However, the change in the ambient temperature affects not only the temperature of the measuring object but also the entire measuring device, and the temperature change of each part of the measuring device is not the same as the temperature change of the measuring object. The correction method is not easy. If such a complicated correction work is not performed, the comparative measurement accuracy naturally lowers, and the precise correction measurement corresponding to the temperature change cannot be performed by the easy correction means. The present invention has been made on the basis of such a point, and the purpose thereof is to have a function of rapidly determining the quality of a measurement object, and even when the environmental temperature of the measurement work changes. An object of the present invention is to provide a three-dimensional comparison measuring device that can obtain high measurement accuracy.

[0007]

In order to achieve this object, a three-dimensional comparative measuring apparatus according to the present invention includes a measuring object held on a measuring table and a probe supported by a slider of the measuring apparatus, which are mutually connected. In the three-dimensional measuring method in which relative movement is performed in the orthogonal X, Y, and Z axis directions, the probe head of the probe is brought into contact with a predetermined measurement point of the workpiece, and the X, Y, and Z coordinate values at this contact point are Comparison and calculation means for comparing the X, Y, Z coordinate values at corresponding measurement points of the master, which are measured and stored in advance, to obtain the subtraction value, and the discrimination result are recorded and displayed in an arbitrary form. With a means for detecting or predicting temperature change during measurement, X at the predetermined measurement point of the master
A master coordinate value updating means for re-measurement of the Y and Z coordinate values and updating the stored master coordinate value appropriately.

[0008]

That is, the three-dimensional comparison measuring device according to the present invention does not measure the three-dimensional dimensions of the measuring object as an absolute value like the conventional measuring machine of this kind, but measures and stores them in advance. By comparing the master data and the measured data of each work, calculating the subtraction value and comparing it with the preset tolerance of each measurement point, the quality of the work can be determined. There is. Therefore, the quality of the work can be accurately and easily determined, and the result of the determination can be used to quickly interlock other related devices. In addition, it is equipped with a temperature calibration function in response to changes in the environmental temperature of the measurement work, re-measures the XYZ coordinate values of the model based on the update command instructed from this device, and stores it in memory. Since the reference data being updated is updated, it is possible to always obtain highly accurate comparative measurement results.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings for showing an embodiment of the present invention, a table 2 as an X-axis slider, which is movable on a base 1 of a machine base in the X-axis direction, is provided, and an object to be measured is provided above the table 2. The surface plate 4 holding 3 is fixed. A column 5 corresponding to the table 2 is erected on the rear side of the center of the base 1, and a Y-axis slider 6 which is freely movable in the Y-axis direction orthogonal to the X-axis is installed above the column 5. Y-axis slider 6
A holding body 9 of a Z-axis slider 8 is provided on the front side of the Z-axis slider 8 so as to be freely movable in the Z-axis direction orthogonal to the X-axis and the Y-axis via the support frame 7. A probe 10 is attached to the lower end of the extension of the Z-axis slider 8 so that the probe 11 is made to correspond to the measurement object 3 and the probe 11 in contact with this measurement surface can be moved three-dimensionally. ..

Driving of the table 2 in the X-axis direction with respect to the base 1, driving of the Y-axis slider 6 with respect to the column 5 in the Y-axis direction, and driving of the Z-axis slider 8 with respect to the holding body 9 in the Z-axis direction are performed. , An X-axis driving device 13, a Y-axis driving device 14, and a Z-axis driving device 15, each of which is composed of a linear actuator, a motor, an encoder, and the like, and is connected to a multi-axis controller 12 having a servo function. The multi-axis controller 12 is, for example, a three-axis servo driver 16, a central processing unit (CPU) 1
7, ROM device 18, RAM 19, interface 2
0 and a power supply unit 21 and the like, and the necessary data from the teaching box 22 is input and stored.

The relative movement amount of the probe 10 in the X-axis direction with respect to the object 3 to be measured is an X-axis scale 23 as an X-axis movement amount reading device provided on the base 1 and the table 2.
The amount of relative movement of the probe 10 in the Y-axis direction and the Z-axis direction is detected by the Y-axis scale 24 associated with the column 5 and the Y-axis slider 6, and the holder 9 and the Z-axis slider 8. It is detected by the Z-axis scales 25 provided in association with each other. Detection signals from the X-axis scale 23, the Y-axis scale 24, and the Z-axis scale 25 are sent to the X-axis counter 29 via the X-axis amplifier 26, the Y-axis amplifier 27, and the Z-axis amplifier 28 shown in FIG. , A Y-axis counter 30 and a Z-axis counter 31 are counted and are counted here, a probe contact signal from the probe 10 is equipped with each counter via a probe amplifier 32 and an interface 33. Since it is input to the counter 34, each of the counters 29, 30, 31 receives X,
The Y-axis and Z-axis movement amount readings can be latched.

There is also a computer 35 connected to the mother board 34 and the multi-axis controller 12 described above, and an operation panel 36 connected to this is also provided. The computer 35 includes, for example, an input unit 37, an output unit 38, interfaces (I / F) 39 and 40, a storage device 41, a control device 42, a calculation device 43, a power supply unit 44, etc. Keyboard 45 if necessary
However, a display 46 and a printer 47 are connected to the output unit 38. On the other hand, the operation panel 36 has an input unit 48 for instructing the operation of the measuring device, a tolerance setting unit 49 for inputting the dimensional tolerance of the measurement point, an individual determination display unit 50 for displaying the comparison and determination results, and a comprehensive determination. Display 51 and tolerance display 52
Etc. are provided. Further, the operation panel 36 and the display 46 are arranged as shown in FIG. 1, for example.

In the case of the present embodiment having the above-described structure, first, a master accurately made based on the manufacturing drawing is prepared,
After accurately measuring the required part size in advance and collecting the data, a predetermined measurement point designated in advance by this device is measured, and this reference data is stored in the device. Next, the dimensional tolerance at each measurement point is calculated based on the dimensional measurement data of the master and the specified tolerance value of the manufacturing drawing, and the tolerance setting unit 4 of the operation panel 36
Input from 9 and put. Then, the predetermined measurement point of the workpiece corresponding to the measurement point of the master is measured, the measurement data obtained by this is compared with the reference data of the master, and the subtraction value is calculated, and this value is calculated first. Compared with the set dimensional tolerance, it judges and displays whether it is within the tolerance,
The quality of the work is determined.

At this time, in order to prevent the deterioration of the measurement accuracy caused by the change of the environmental temperature of the measurement work, the following means are adopted. First, the temperature of the work to be measured is constantly measured by the temperature sensor 53, and the temperature calculation unit 54 checks how much the temperature has changed from a predetermined time point, and the temperature comparison unit 55 uses the temperature difference setter in advance. In comparison with the value set in 56, if the value of the temperature calculation unit 54 exceeds the set value, an activation signal is output to the measurement value update command unit 57. On the other hand, a time measuring device 58 for detecting the lapse of the measuring time is provided, and the time from the predetermined time point is calculated by the time calculating unit 5
9, the time comparison unit 60 compares this value with the value set in the time difference setting unit 61 in advance, and when the value of the time calculation unit 59 exceeds the setting, the measured value update command unit 57 is notified. Make the start signal.

At this point, the measured value update command unit 57 issues a command to update the reference data when it receives a start signal from either the temperature comparison unit 55 or the time comparison unit 60. Temperature calculation unit 54 and time calculation unit 59
Since the count value of is simultaneously cleared to zero, the master measurement value update command does not overlap between the temperature difference interval and the time difference interval.

The above configuration can be shown in the block diagram of FIG. That is, in normal measurement, X, Y, Z of the workpiece
The coordinate value and the X, Y, Z coordinate values of the master are compared by the comparison operation unit 62 to calculate the subtraction value, and then the subtraction value and the dimensional tolerance input from the tolerance setting unit 49 are calculated. The comparison determination unit 63 determines. This result is recorded or displayed via the record display unit 64. The calibration with respect to the temperature change is performed by the master coordinate value updating means 65. That is, the master measurement value update command unit 57 is activated by the signal from the work temperature sensor 53 system and the signal from the time measuring device 58 system to update the reference data.

The operation of the thus constructed apparatus will be described with reference to the flow chart shown in FIG. 5. In the normal measurement procedure, first, the master is held on the surface plate 4 of the table 2 by using an appropriate jig ( Step a). This operation is automatically performed by a transfer robot or the like due to automation of the measurement line, and when the robot arm retracts, the measurement operation starts (step b). Next, sampling (step c) is performed, and this sampling is performed with respect to a predetermined number of preset measurement points of the master held on the surface plate 4.
This means that the probe 11 of the probe 10 is contacted a plurality of times (for example, three times), the X, Y, Z coordinate values at that time are read, and the average value of these is registered (stored) as reference data. There is. This work takes in data at each measurement point of the master (step d), calculates it (step e), and stores it (step f).
Complete the acquisition of reference data

Next, the measurement of the work 3 is started. First, the master is removed from the surface plate 4 and the work 3 is held instead (step g). However, these operations are actually performed automatically by the transfer robot, and the removed master is used for the measurement work and the environment. They are placed in designated places with the same temperature conditions. In this state, the measurement operation is started (step h) and probing (step i) is performed. The probing is an operation in which the probe 10 touches the measuring element 11 to each measuring point (once a time) and moves, and corresponds to the sampling at the time of the master measurement described above. The data of the X, Y, Z coordinate values at the measurement point is loaded (step j). The data taken in is stored (step k) and, at the same time, is subjected to arithmetic processing (step l).
That is, the already stored master reference data is selectively taken out (step m), this data and the data obtained by the measurement of the work are compared and calculated (step l), and the subtracted value is calculated. At this point, the subtraction value for each axis is displayed on the individual determination display section 50 of the operation panel 36.

Further, the dimensional tolerance of the measurement point (tolerance to the reference data) is set in advance in correspondence with the above comparison and calculation, and this is stored. That is, the tolerance setting (step n) is input and stored (step s) under the conditions of position selection (step p), axis selection (step q), and upper and lower limit value selection (step r). This stored tolerance is taken out from the stored tolerances during the above-described arithmetic processing (step 1), and the tolerance for which the axis has been selected at the desired measurement point is taken out (step t). (Difference between the measurement data and the reference data) is compared (construction u). If the subtraction value is within the tolerance as a result of this comparison, OK for each axis as a good product.
The display (green) is turned on (step v), and when the subtracted value is outside the tolerance, the NG indicator (red) is turned on as a defective product (step w). Such determination for each measurement point is the individual determination, and the respective indicator lights are installed on the individual determination display unit 50 of the operation panel 36.

After the above individual determination, a comprehensive determination (step x) is performed. In this process, "OK" is displayed (process y) only when the calculated values of each axis at each measurement point are within the tolerance, and the tolerance is satisfied even at one place under all conditions at all measurement points. If a value not to be detected is detected, "NG" is displayed (step z). After the above steps have been completed, the measurement for one work is completed (step A), and after each operating part returns to the origin (step B), the work is removed (step C) to prepare for the next measurement. Become. In the course of such a series of steps, data can be output if necessary, and can be displayed on the display 46 or printed by the printer 47, for example. In addition, if it is configured to output the result of comprehensive judgment to a transfer robot,
For example, a non-defective product may be conveyed to an arbitrary non-defective product line, and a defective product work may be conveyed to another processing line. For example, the non-defective product and the defective product may be automatically sorted or sorted and stored.

The calibration associated with the temperature change will be described below. Sampling of the master is always executed at the start of the measurement work. The temperature sensor 53 constantly measures the temperature of the work during the measurement work, and the temperature calculation unit 54 checks the change value from the work temperature at the first or previous master sampling. On the other hand, a predetermined command temperature is set in advance in the temperature difference setter 56, and as a result of the temperature comparing unit 55 determining the value of this value and the value of the temperature calculating unit 54, if the temperature change value of the work is large, A signal is output to the measurement value update command unit 57, and the master coordinate value update command (step D) is thereby output from the measurement value update command unit 57.

In addition to this, there is a time measuring device 58,
The time calculation unit 59 checks the elapsed time from the end of the sampling work, and this integrated value is used as the time setter 6
When the predetermined value set to 1 is exceeded, the time comparison unit 60 makes a determination and notifies the measurement value update command unit 57, so that the master coordinate value update command (process D) is also performed by this signal. Be seen. The purpose of this time difference temperature calibration is
When the temperature change of the work becomes gradual, this is to reduce the measurement error caused by the change of the temperature difference between the work and each axis scale. Because it does not overlap with the command, unnecessary sampling is not performed and the efficiency of measurement work does not decrease.

When the above-mentioned update command (process D) is issued, this work is interrupted (process E) even if the measurement of the work is in progress, and each moving part returns to the origin (process F). hand,
The work is removed from the measurement surface plate (process G). Then, the reference data is captured again. That is, the operations from “process a” to “process f” already described are performed on the master placed in the same environment as the work, and the reference data is updated. After the update work is completed, normal work measurement will be continued again.

The present invention is not limited to the above embodiment. For example, as the master coordinate value updating means 65,
A method of using the time setting device 66 shown in FIGS. 4 and 5 is conceivable in addition to the above-described apparatus that combines the temperature difference detection and the time difference detection. In other words, in the process of measurement, how the temperature of the work and each part of the measuring device changes according to the change of the environmental temperature and the measuring work is measured and analyzed in advance, and the reference data is updated based on this data. This is a method of programming the timing to be performed in the time setting device 66. Specific examples are the "update reference data every time an appropriate set time elapses" method and the "set a suitable time for updating the reference data" method. Can also reduce the decrease in measurement accuracy due to temperature changes.

[0025]

As described above, the three-dimensional comparative measuring apparatus according to the present invention does not simply measure the three-dimensional absolute value of the work, but the reference data of the master previously measured and stored and By comparing and calculating the measured data of the work, and comparing the subtracted value with the preset tolerance value, the quality of the work can be determined. Can be determined. In addition, other interlocking devices (eg, transfer robot, conveyor, palletizer, etc.) can be used by using the signal of the judgment result.
It is also possible to control, and it is possible to automate the process of classifying good products and defective products.

In particular, the feature of the device of the present invention is that the master is used to update the reference data for the purpose of temperature calibration. This is because the master is made of the same material as the work to be measured, and the shape, dimensions, and thickness of each part are made identical so that the thermal fluctuation characteristics are the same and the master is placed in the same temperature environment as the work to be measured. In order to cancel the dimensional change of both due to thermal expansion, the correction of the reference data due to temperature change is made accurate and easy. In addition, the incorporation of an operating time calculation / comparison system as the master coordinate value updating means means that the temperature change of each part of the measuring device (especially of each axis scale) follows the changes of the environmental temperature and the work temperature with a delay. This is a consideration, and updating the master reference data based on these can effectively prevent a decrease in measurement accuracy due to a temperature change.

[Brief description of drawings]

FIG. 1 is a front view of a three-dimensional comparative measuring device showing an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a block circuit diagram of a three-dimensional comparative measuring device showing an embodiment of the present invention.

FIG. 4 is a functional block diagram of the apparatus shown in FIG.

5 is a flow chart of the apparatus shown in FIG.

[Explanation of symbols]

 2 table (X-axis slider) 3 measurement object 6 Y-axis slider 8 Z-axis slider 10 probe 11 probe 12 multi-axis controller 23 X-axis scale 24 Y-axis scale 25 Z-axis scale 35 computer 36 operation panel 46 display 47 printer 53 Temperature sensor 56 Temperature difference setting device 58 Time measuring device 61 Time difference setting device 66 Time setting device

Claims (3)

[Claims] 1. A three-dimensional measuring method in which a measuring object held on a measuring table and a probe supported by a slider of a measuring device are relatively moved in X, Y, and Z axis directions orthogonal to each other. , The probe head is brought into contact with a predetermined measuring point of each measuring object (hereinafter referred to as a workpiece), and X.
The Y and Z coordinate values are measured in advance and stored at the corresponding measurement points of the model measurement object (hereinafter referred to as the master).
Comparison calculation means for comparing the Y and Z coordinate values to obtain the subtraction value, comparison determination means for determining whether or not the subtraction value is within the preset tolerance of each measuring point, and this determination It has a means to record and display the results in any form,
Furthermore, by detecting or predicting the temperature change during measurement, the X, Y, Z coordinate values at the predetermined measurement points of the master are measured again,
A three-dimensional comparative measuring apparatus comprising: a master coordinate value updating unit that appropriately updates the stored master coordinate value. 2. The temperature change value of the workpiece temperature detection sensor is
At any time when the value exceeds the preset value or when the elapsed time of measurement work exceeds the set value, the X, Y, Z coordinate values of the master are remeasured and the stored reference data is updated. The three-dimensional comparative measuring device according to claim 1, further comprising: 3. The three-dimensional comparison measuring apparatus according to claim 1, further comprising a function as a master coordinate value updating means for instructing an update of the reference data by a time setter in which a designated point of the measurement work time is programmed in advance.