JPS6171969A - Nc grinder with revolving correction tool - Google Patents

Abstract

PURPOSE:To facilitate fitting work of a correction tool by previously measuring dislocation of the center of revolution from the tool reference point, and thereby correcting automatically the processing error due to such a dislocation in any position of revolving. CONSTITUTION:A control device emits a target value A for A-axis to determine the revolving angle of an arm 3 and also the target values Y and Z for Y- and Z-axes with necessary corrections for the processing error generated by incoincedence of the center of revolution O1 from the correction tool reference point O2 in any arm revolving position. The target value A is sent to the driver device for a servo motor 5, which is driven so that the revolving angle of the arm 3 will be identical to the corresponding target value. The target values Y and Z are sent by driver devices for servo motors which are to move the location of a grinding wheel 7 in the Y- and Z-axes, and the location of the grinding wheel 7 is so shifted as to be identical to the target value. This may fracilitate the fitting work for correction tool 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a numerically controlled grinding machine having a pivotable correction tool and capable of two-dimensional interpolation.

(Technical background of the invention and its problems) FIGS. 1(A) and 1(B) are schematic configuration diagrams of a grinding wheel correction device to which this invention is applied. It will be installed in Servo motor 5
The rotation of the arm 3 causes the arm 3 to pivot, and the pivot position of the arm 3 is detected by a rotary encoder 6. The grinding wheel 7 is rotationally driven by a grinding wheel drive motor (not shown), and the position of the grinding wheel 7 is numerically controlled with respect to the vertical Y axis and the rotating Z axis. The correction tool l is aligned and fixed in advance to the correction tool holder 2, and the correction tool holder 2
is fixed to the tip of the arm 3. The rotation position of this arm 3 is also numerically controlled, and this is defined as the A-axis. With the grindstone correction device having such a configuration, the grindstone is corrected by controlling the position of the grindstone using the Y-axis and the Z-axis and controlling the rotational position of the correction tool 1 using the A-axis.

In a device that rotates around the point of application of the tool, such as the above-mentioned grinding wheel correction device, if the reference point of the tool and the center of rotation do not match, the tool reference point will move as the tool is rotated (17). This results in machining errors.

For this reason, conventionally, the tool reference point was made to coincide with the turning center to obtain an IJL of +1. However, it is a difficult task to mount the tool so that the reference QIB point and the center of rotation are completely aligned, and it is necessary to set the tool to a value that satisfies the deviation between the focus and the center of rotation, e.g. It took a lot of time to install it so that it was within ±Igm.

(Object of the Invention) This invention was made in view of the above circumstances, and it is possible to prevent I-center deviation in the tool rotation plane of a numerically controlled grinder even if the tool reference point and the rotation center do not coincide. By measuring.

The object of the present invention is to provide a numerically controlled grinding machine with a rotating correction tool that can automatically correct machining errors at any turning position.

(Summary of the Invention) The present invention relates to a numerically controlled grinding machine that has a rotatable tool and is capable of two-dimensional interpolation. too,
By measuring the amount of tool misalignment at two specific rotation positions before machining and calculating the deviation between the tool reference point and the rotation center, the tool reference point and rotation center can be aligned at any rotation position. This corrects the amount of tool positional deviation caused by not doing so to prevent machining errors from occurring.

(Embodiment of the Invention) FIG. 2 shows the grindstone correction device main body 4 of the grindstone correction device shown in FIG. It is. The rod 9 is fixed to the grinding wheel correction device main body 4 by a bolt IO,
A dial gauge 8 for detecting a positional amount is provided at the tip of the rod 9. On the other hand, the tip of the correction tool l is the third
As shown in the figure, it is a circular arc centered on the correction tool reference point 02, and the tip of the correction tool l comes into contact with the measurement surface 81 at the tip of the dial gauge 8, as shown in FIG. As shown in FIG. 5, the dial gauge 8 indicates the displacement of the tip of the correction tool 1 with respect to the center of rotation 0°.

FIG. 6 shows a schematic diagram of a control device for correcting the grindstone by correcting the deviation between the correction tool reference point 02 and the turning center 01 based on the measurement results of the error measuring device 20. The program punched on the tape is read by a paper tape reader 54, and the read program is stored in a program memory 55 connected to the paper tape reader 54.

A decoder 56 is connected to the program memory 55, and when the program start signal PST is input, the decoder 56 analyzes one block of the program and
Send the axis and Z-axis interpolation commands CYZ to the function generator 57,
The A-axis interpolation command CA is sent to the function generator 'x58. on the other hand,
The measurement results L1 and L2 of the error measuring device 20 are manually input to the keyboard switch 50, and are input to the arithmetic unit 51. The arithmetic unit 51 calculates the magnitude of deviation β and angle θ from these data Ll and L2, and sends them to registers 52 and 53 to be stored, respectively. The calculation unit 59 then stores the magnitude of the deviation stored in the register 52! , the value of the angle θ stored in the register 53, and the target value A of the A-axis generated by the function generator 58 are input, and correction values JT and dZ of the Y-axis and Z-axis are calculated, respectively.

The Y-axis and Z-axis correction values av, ttz calculated in this way
and the Y-axis and Z-axis target values Y generated by the function generator 57.
O and ZO are each input to an adder 60, which calculates and outputs target values Y and Z that correct machining errors due to mismatch between the tool reference point and the center of rotation.

Target values A for the three axes, the A-axis, Y-axis, and Z-axis, are output by the control device in this way.

Y and Z are respectively sent to a drive attachment of a servo motor 5 (not shown) and a servo motor drive device (not shown) that positions the Y and Z axes of the grinding wheel 7, and the correction tool l The angle and position of the grinding wheel 7 are determined.

A description will be given of how the error measuring device 20 and the control device configured as described above are used to correct machining errors caused by the deviation when the correction tool reference point 02 and the rotation center O8 do not match at any rotation position of the arm 3. .

First, in order to calculate the deviation between the tool reference point 02 and the turning center 01, the positional deviation of the tool at two specific turning positions of the arm 3 is measured before machining. For that purpose, the second
As shown in the figure, a rod 9 having a dial gauge 8 disposed at its tip is fixed to the grinding wheel correction device main body 4 with a bolt IO. In this state, rotate the servo motor 5 to rotate the arm 3 so that the correction tool 1 points in the Y-axis direction, that is, in the vertical direction, as shown in FIG. read Next, rotate the servo motor 5 again to move the arm 3 counterclockwise by 45 degrees.
Turn the correction tool 1 by 45 degrees as shown in FIG. 5, and read the indicated value L2 on the dial gauge 8 at this time.

In this way, the indicated values Ll and L of the dial gauge 8 are
2 is read by an operator or the like, and the reading increase values L1 and L2 are input as data using the keyboard switch 50. Reading L1 entered using keyboard switch 50
and L2 are input to the calculator 51, and the turning center 0! as shown in FIG. 3 is determined according to the following calculation formula. Modified tool reference point from 0
Calculate the magnitude and argument θ of the vector toward 2.

(2-F171 "77...
・(1) o-= tso°+tan-' (z/y)
--・"(2) However, y=L1-r z = (y/ "■-(L2-r))/1 block The values of lag acid! and θ calculated in this way are stored in register 52 and θ, respectively. It is sent to register 53 and stored.

- On the other hand, the machining program read by the tape reader 54 is once stored in the memory 55.

Then, when the program start command signal PST is applied, the decoder 56 reads out one block of the program from the memory 55. The decoder 56 analyzes the read program for one block and sends a Y-axis and Z-axis interpolation command CYZ and an A-axis interpolation command CA to the function generator 57 and function generator 5, respectively. The function generator 57 uses the interpolation command CYZ to calculate Y of the position of the grinding wheel 7 when there is no deviation between the corrected tool reference point 02 and the turning center 01.
Output target values yo and zo for the axis and Z axis. Further, the function generator 58 outputs a target value A of the rotation angle of the arm 3 based on the interpolation command GA. This target value A, the absolute value 1 of the deviation between the corrected tool reference point 02 and the turning center OI stored in the register 52, and the vector deviation toward the corrected tool reference point 02 from the turning center OI stored in the register 53. Based on the angle θ, correction values JV and jZ of the target values for the Y-axis and the Z-axis are calculated using the calculator 59. Here, the calculation formula is as follows.

ttt=i self cos(θ+A)...・Fist ψΦ・Φ fight...(
3), 7 z = l” S11 (θ+A)...
(4) The results JY and JZ calculated by the arithmetic unit 58 according to the above equations (3) and (4) are both sent to the adder 60, and the adder 60 calculates 'y =vo+ljy・・・・・・・・・
...(5) Z=ZO+jz ・
・・・・・・・・・・・・(6) The following addition is performed, and the target values Y and Z are output by correcting the target values YO and ZO for the Y-axis and Z-axis of the grinding wheel 7 when there is no deviation. be done.

The control device as described above prevents machining errors caused by the mismatch between the target value A of the A-axis that determines the rotation angle of the arm 3 and the correction tool reference point 02 and the rotation center O1 at any rotation position of the arm 3. The corrected Y-axis target value Y and Z-axis target value Z are output. The target value A is sent to the drive device (not shown) of the servo motor 5,
The servo motor 5 is driven so that the rotation angle of the arm 3 matches the target value. In addition, the target values Y and Z are sent to a servo motor drive device (not shown) that moves the position of the grinding wheel 7 in the Y-axis and Z-axis directions, respectively, so that the position of the grinding wheel 7 corresponds to [1]. will be moved to

In the second embodiment, the measurement result L1 of the error measuring device 20
and L2 are input manually using the keyboard switch 50, but they may also be input directly to the control device using a potentiometer, a digital switch, or the like. Furthermore, although the embodiment described above is applied to a grinding wheel correction device, the present invention can be applied in exactly the same way to any grinding machine where errors in mounting a tool are a problem.

(Effects of the Invention) According to the present invention, even if the tool reference point of a rotatable correction tool and the rotation center do not coincide, the deviation between the tool reference point and the rotation center can be measured in advance. By doing so, it is possible to automatically correct machining errors due to this shift at any turning position. Therefore, machining errors caused by the deviation between the tool reference point and the center of rotation can be eliminated. Furthermore, it is no longer necessary to mount the tool so that the tool reference point and the center of rotation completely match, and the mounting of the swivel tool becomes easier.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are side and front views of a grindstone correction device to which the present invention is applied, Figure 2 is a configuration diagram of the grindstone correction device with an error measuring device attached, and Figure 3 is a grindstone correction device. Figures 4 and 5 are enlarged views of the contact area between the correction tool and dial gauge when the error measurement value is attached to the grinding wheel correction device, and Figure 6 is a diagram showing the shape of the tip of the correction tool. It is a schematic block diagram of the control device of the applied grindstone correction device. 1... Correction tool, 2... Correction tool holder, 3...
Arm, 4... Grinding wheel correction device body, 5... Servo motor, 7... Grinding wheel, 8... Dial gauge, 20
...Error measuring device. (A) 2. Figure 2 Figure 3 Figure L4 Figure 5

Claims (1)

[Claims] In a numerically controlled grinding machine that has a rotatable tool and is capable of two-dimensional interpolation, the amount of positional deviation of the tool in the tool rotation plane is measured before machining, and the deviation between the tool reference point and the rotation center is calculated. With a swiveling correction tool, the amount of positional deviation of the tool due to mismatch between the tool reference point and the swivel center at any swiveling position is corrected to prevent machining errors from occurring. Numerical control grinding machine.