JPS6114836A - Coordinates system correcting device of machining position - Google Patents

Abstract

PURPOSE:To increase the precision for circumferential machining by adding the detected value of the center drift between a work and a table in the rectangular coordinates to the machined positional data than correcting the machining head position with the calculated value converted into the polar coordinates from the rotation center. CONSTITUTION:A standard virtual point where a touch sensor is moved during measurement is assumed, rectangular two-axis coordinates are set, then the touch sensor is fitted to a main spindle end, and the centering correction quantities along X, Y axes are measured and stored in RAMs 31-34. Next, an average value is calculated by an arithmetic unit 35 and is stored, and the center position C1 is calculated by an arithmetic unit 38, then the drift quantity against the position C1, i.e., correction velue (a) on the X axis, is obtained by an arithmetic unit 39, the correction value (b) for the Y axis is determined by turning a table by 90 deg., and they are stored in RAMs 40, 41. Next, when machining data are inputted from an information input means 5, the rectangular coodinates value using the work center C1 of the machined position as an origin is calculted, and correction values (a), (b) are read out from the RAMs 40, 41 to correct the coordinates value. Then, it is converted into the polar coordinates from the table rotation center C2, and the table is turned to perform a punching operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinate system correction device for machining positions in machine tools such as NC lathes and drilling machines, and particularly for machining multiple small holes arranged on the circumference of a workpiece with high precision. Therefore, the present invention relates to a coordinate system correction device suitable for machine tools that control machining heads using a polar coordinate system.
''' Conventionally, machining centers that control the three axes of the X-axis, C-axis (rotation axis), and Z-axis also place the workpiece on a rotatable table and arrange it around the circumference of the workpiece. In order to machine multiple small holes with high precision, the rotation center of the table, the workpiece center, and the spindle center must be aligned accurately and placed. This eliminates the need to position the workpiece directly below the processing head.
There is a need for improved mounting accuracy, the fixture mechanism is complicated and expensive, and the center of the spindle changes over time, making it difficult to achieve a completely accurate fix.

Fig. 1 is a side view of a vertical machining center. In Fig. 0, a workpiece W is placed on a table T rotatably attached to a ped D, and a column L attached to a bend D is used for machining. This is carried out by a tool inserted into the spindle H of the processing head Z, which is mounted so as to be movable up and down. Tools attached to spindle H are from magazine M to AT
C (not shown), and when measuring a workpiece, etc., the touch sensor can be called out from the magazine M and attached. Figures 2 (A) and (υ) are plan and side views showing the state in which the workpiece is placed. The workpiece W is fixed to the base B of the rotatable table T by a fixture F, and the workpiece W is fixed to the base B of the rotatable table T. It is linked to the movement movement. An example of a machining operation suitable for consideration here is as shown in Figure (A), where workpiece positions P+, P are arranged concentrically with respect to the center C of a circular workpiece W.
a.

...P, the pore diameter! When attempting to drill a small hole,
The position of the workpiece and the machining position of the machining head are completely different.
By simply rotating the table T, the workpiece position is positioned relative to the machining head) and can be easily controlled. Since the center cannot be accurately determined, the accuracy of machining cannot be improved.Also, if we tried to treat this deviation as a mere positional deviation, the precision would inevitably deteriorate due to polar coordinates.

In view of the above-mentioned problems, an object of the present invention is to avoid the lk/j misalignment between the center of the table side and the center of the workpiece side.

Even if the circumferential machining position is not offset, the deviation is centered and measured, and the difference in the coordinate system is corrected to realize high-precision machining of circumferential machining positions at low cost.

In order to achieve the above object, the present invention provides a workpiece centering measuring means for detecting the deviation between the center of the workpiece and the center of rotation of a table using orthogonal coordinates, and a storage means for temporarily storing the measured value as a centering correction amount. ', a calculation means that adds the centering correction amount to the data of each workpiece position and converts the calculated rectangular coordinate value into a polar coordinate value from the rotation center, and a table using the calculated value. The apparatus is characterized by comprising a central control means that sequentially issues machining instructions to rotate the machining head and correct the position of the machining head.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a schematic configuration diagram showing an example of a machining position coordinate system correction device embodying the present invention. In the figure, the machining position coordinate system correction device is a central control unit (CPU, from now on, C
(abbreviated as PU) 1, a work centering measurement means,
The main bus 11 from the CPU is provided with an information input means for inputting data such as the machining position, and a motor control means for positioning the machining head relative to the workpiece. is connected.

FIG. 4 is a flowchart showing an example of a machining procedure by a drilling machine equipped with the above coordinate system correction device. In the figure, the first stage of the procedure is the workpiece centering procedure (rl) performed by the workpiece centering method, and then the second stage is the small hole drilling procedure (11). The hole measurement procedure (III), which is the third stage of the zero procedure, which is executed using the correction amount from the storage means 3 via the calculation means 4 and the motor control means 6, is an inspection of the machining result, and is performed to check whether the hole diameter is correct. If it is too small, it will be reprocessed, and if it is too large, it will be defective.

Next, each stage of the above procedure will be explained. .

FIG. 5 is a flowchart showing an example of a workpiece centering procedure used in the present invention. In the figure, the constant settings include the length of the touch sensor, the diameter of its probe, and the tool number of the touch sensor, and the coordinate system settings include After assuming a virtual point and setting orthogonal two-axis coordinates, the touch sensor is retrieved from the magazine and attached to the spindle end as described above.Measurement is performed at the sixth
As shown in Figure (A), along the set X-axis, the probe is brought into contact with the outer circumference of the workpiece from the X-plus side and the X-minus side, and the probe is rotated 180 degrees for each point. To the value + + A + B1. and B mushrooms are obtained. Furthermore, the table was rotated 180 degrees and similarly measured values As, Am, and Bs were obtained.

and B4, the centering correction 1ia along the Y axis is measured at a total of 8 points. The correction amount when the center of the workpiece W is on the plus side than the center of the table is aO, and 1
For correction when turning 80 degrees to the negative side, use a□
Then, a = (8, +R, +A, +B, )
+4- (1) a○= (8, →-B3 ”Aa
'+Ba)'' 4-+2) (11, +21, a =
(a○+a□)+2Similarly, measurement along the Y-axis G is also
Touch the probe along the Y axis or move the table to 90
Repeat the measurement by rotating the probe 180 degrees to obtain measured values C+, Cz, C+, and Dz. Furthermore, rotate the table 180 degrees and measure value C3 in the same way.
゜If you get Ca, Ds and B4, the total is 8 points,
Centering correction amount along the Y axis - (C+ +D1 +C1+p value) + 4... (3
)be-(C3+D!+Ca+DI)+4・13
)131, (41,k Rib −(bΦ+be)+2
m4. ＝Togaderu.

That is, these measured values A+, As, C+, Cs are α+, At, Aa, Ct, Ca are α8. B
1Bs, Dt, Ds as αs, Bz, Ba, D
t and Da are stored from the RAM 31 to the RAM 34 as α4.

Next, the computing unit 35 calculates the average value (α, +α, +α, +α4) + 4, and the calculation results of the center position when the workpiece is at 0° and after turning 180° are β
They are stored in the RAM 36.37 as Φ and βe.

Next, when the center position C8 of the workpiece is calculated from (βΦ+βO)+2 in the calculator 38, the amount of deviation from the center position, that is, the correction value a on the X axis is obtained by the calculator 39 from βΦ−G, and Y Correction for the axis (!Ib is the table 9
It can be determined by rotating the coordinate system by 0° and shifting the coordinate system on the X-axis.

These correction amounts a and b are stored in the RAM 40.41.

When the origin setting is completed, the touch sensor is returned to the magazine and returned to the A'rC (automatic tool changer) state.

Now, when machining data is input from the information input means 5 shown in FIG. 3, and the loss N of the workpiece position and the radius R from the circumferential hex center C4 connecting the workpiece positions are obtained, each workpiece position Right angle pressure +1 (a is calculated as follows) with the workpiece center C+ as the origin.

The orthogonal coordinate values x7' and y'a of the n-th workpiece position Pn in the counter-time direction from the Y-axis are the mouth deviations αn from the Y-axis, αn-α×n, (α-360/N ), x'n = Rcos (αXn) y'n - Rsin (crxn) This rectangular coordinate value is stored in the RAM 40.
Extract the correction amounts a and b from 41 and calculate the seat MI as follows.
Correct the value. Note that the numerical values βΦ and βe from the two RAMs 36 and 37 are added in the computing unit 33 and then divided into two to calculate the workpiece center Ct, and the computing unit 39 calculates the table rotation center G! The differences a and b in the X and Y directions between the two are outputted as correction amounts, respectively.

FIG. 6 (I+) is a plan view illustrating the geometric relationship of coordinate value calculation, and as shown in FIG. When corrected, the orthogonal coordinate values Xn and Yn of the workpiece position Pn with the table rotation center C8 as the origin are (xs of this calculation)
The exchange of ', )'e takes place in the polar/quadrature circuit 41.

) Xn=a +x11'-a +Rcos (αxn)Y
n=b+yll'-b+Rsin (αxl), which is the table rotation center C! When converted to polar coordinates from Rn-, /Xn +Yn Q n = jan -' ((b+R51n(
αXn)) /(a+Rcos (&+n))) This calculation is performed by the right angle/rake circuit 42 and the CPLI
Sent to 1.

FIG. 7 is a flowchart showing an example of a small hole machining procedure, using the polar coordinate values converted by the above coordinate value calculation,
By moving the table Qn [i7 and positioning the X-axis position of the machining head at Rn, perform the drilling work on the workpiece W using the prescribed tool, and process this in a loop for N pieces. Finish.

Finally, the hole diameter measurement procedure for inspecting the results of the machining work using the polar coordinate system used in this example will be described. Fig. 8 is a flowchart showing an example of the pore diameter measurement procedure, and Fig. 9 is a plan view showing the geometrical relationship. Insert the probe P of the touch sensor into the small hole, and find the table polar coordinate value Q1 where the inner edge of the small hole touches the probe P at the end of the forward direction of rotation, and Ql where the inner edge of the small hole touches the probe P at the end of the backward direction of rotation. . When these two values are obtained, the polar coordinate value Qs of the center of the small hole becomes Ql w (Ql −
Since it is obtained as Ql ) +2, rotate the table and align the center of the small hole and the touch sensor on the X axis, and move the probe to the
Moving along the ring and detecting the coordinates of touching the inner edge of the small hole on the left and right sides, if the diameter of the probe is d, then
The right angle of the small hole is detected as D-d+ (right touch left touch). This D is the specified data filament! Inspections can be carried out in comparison to

As explained above, according to the present invention, even if there is a minute deviation between the center of the table side and the center of the workpiece side, the deviation is centered and measured, and the difference in coordinate systems is corrected. can now be processed using polar coordinates from the rotation center of the table, making it possible to perform high-precision machining on containers at circumferential machining positions, eliminating unnecessary costs for fixed chairs, and speeding up and streamlining operations. It also exhibits excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a side view of the drilling machine, Fig. 2 is a plan view and side view showing the workpiece placement state, Fig. 3 is a schematic configuration diagram of the coordinate system correction device of the present invention, Figs. Figure, 7th
8 and 8 are flowcharts explaining the invention in detail, and FIGS. 6 and 9 are plan views explaining the invention geometrically. 1...CPLJ 2...Workpiece centering measuring means 3...Storage means 4...Calculating means 5...
Information input means 6...Motor control means W...Workpiece T...Table ■1...Machining head P
+, 'P x ~ P, ... processing position. Patent applicant Hitachi Seiki Co., Ltd. (da) 1'/a
) Figure 4 Figure 5 12 ＼- Spear 7rll

Claims (1)

[Claims] A coordinate system correction device for machine tools that places a workpiece on a rotatable table and performs machining at multiple workpiece positions arranged on the workpiece surface using a machining head controlled by polar coordinates from the center of rotation. , a workpiece centering measuring means for detecting the deviation between the workpiece center, which is the center of a virtual concentric circle connecting the workpiece positions, and the rotation of the table using rectangular coordinates, and a storage means for temporarily storing the measured value as a centering correction amount. and,
a calculation means that adds the centering correction amount to the data of each workpiece position and converts the calculated rectangular coordinate value into a polar coordinate value from the rotation center; and a calculation means that uses the calculated value to rotate the table. , and central control means for sequentially issuing processing instructions to correct the position of the processing head.