JPH0373251A - Dead zone correcting device in electric discharge machine - Google Patents

Abstract

PURPOSE:To ensure the correction of a dead zone and improve the precision of its form by providing a correcting section for a preset axial direction, in which a dummy block is generated to move a preset axis by a certain correction amount prior to current movement when it is different in direction from previous movement. CONSTITUTION:As the result of comparison by comparison sections 31X, 31Y, 31Z, when current movement is different in direction from previous movement, a dummy block to move a preset axis by a certain correction amount is generated in the correction sections 33X, 33Y, 33Z prior to the current movement. It is thus possible to ensure the correction of a dead zone and therefore to improve the precision of its form.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electric discharge machine, and in particular, a table, a Taber device, etc. are driven by a motor, and when the rotation direction of the motor is reversed, a dead zone (back The present invention relates to a dead zone correction device for correcting rash.

[Prior Art] In conventional electric discharge machines, when a table, a Taber device, etc. are driven by a motor, a dead zone is corrected when the rotational direction of the motor is reversed.

In the conventional electric discharge machine described above, correction of the dead zone is controlled by the relationship between the amount of movement and the amount of correction of the dead zone.

[Problem to be Solved by the Invention] In the above-mentioned conventional device, the total amount of movement is the sum of the dead zone correction amount and the movement amount, so as long as the movement amount changes, including the correction of the dead zone. There is a problem in that the trajectory of movement deviates from the ideal shape.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dead zone extracting device for an electrical discharge machine that can improve the shape accuracy when correcting the dead zone.

[Means for Solving the Problems] The present invention moves the predetermined axis by a certain correction amount prior to the current movement when the current movement direction and the previous movement direction are different in the predetermined axis direction. This generates a dummy block.

[Operation] The present invention generates a dummy block that moves the predetermined axis by a certain correction amount prior to the current movement when the current movement direction and the previous movement direction are different in the predetermined axis direction. Therefore, the dead zone can be reliably corrected, and the shape accuracy can therefore be improved.

[Example] FIG. 1 is a block diagram showing one embodiment of the present invention.

In this embodiment, N
C program decoding section 20, X-axis circumference control section 30X, and Y
It has an axis circumference control section 30Y and a Z-axis circumference control section 30Z.

The X-axis circumference control section 30X supplies the X-axis movement amount data to the X-axis circumference motor based on the data from the NC program decoding section 20, and also supplies the dead zone (backlash) correction amount data to the X-axis circumference. It supplies the motor.

This X-axis circumference control section 30X includes a moving direction comparison section 31X,
It has an interpolation section 32X and a correction section 33X.

The moving direction comparison section 31X is a section that compares the previous moving direction on the X axis and the current moving direction based on the data from the NC program decoding section 20, and the interpolating section 32
X is a part that interpolates data regarding the movement of the X axis from the NC program decoding section 20. In addition, the correction unit 33X
generates a dummy block that moves the X-axis by a certain correction amount (for example, 2.3 pulses) before the current movement when the current movement direction and the previous movement direction are different in the X-axis direction. It is a part. Note that the output signal of the X-axis circumference control section 30X is supplied to an adder 40 shown in FIG. 2.

The Y-axis circumference control section 30Y and the Z-axis circumference control section 30Z have the same functions as the X-axis circumference control section 30X. In addition,
The Y-axis circumference control section 30Y includes a movement direction comparison section 31Y, an interpolation section 32Y, and a correction section 33Y, and the Z-axis circumference control section 30Z includes a movement direction comparison section 312, an interpolation section 32Z, and a correction section 33Z.
and has. Note that the moving direction comparison units 31Y and 312 are
It is similar to the movement direction comparison section 31X, and the interpolation section 32
Y and 32Z are similar to the interpolation section 32X, and correction sections 33Y and 33Z are similar to the correction section 33X.

FIG. 2 is a diagram showing an example of an X-axis drive section.

In FIG. 2, data (signal) from the X-axis circumference control section 30X is supplied to an adder 40, the output signal of the adder 40 is amplified by an amplifier 41, and a motor 42 is activated based on this amplified signal. The shaft rotates, and the pole screw 46 is driven via the coupling 45. A processing table 50 moves in a predetermined direction as the pole screw 46 is driven, and a linear scale 51 is provided near the processing table 50. Note that a speed detector 43 detects the speed of the motor 42.
and a position detector 44 are provided.

Figure 2 shows the X-axis drive unit, but the Y-axis,
The drive for the shaft is also similar to that shown in FIG.

Next, the operation of the above embodiment will be explained.

FIG. 3 is a flowchart showing the operation focusing only on the X-axis in the above embodiment.

First, from the NC program decoding section 20 to the X-axis circumference control section 30
X receives the data (Sl), and the moving direction comparator 31X analyzes the moving amount and the moving direction regarding the X axis, and stores the analyzed data in a storage section (not shown) (52).

If the analyzed movement directions are different, that is, the previous movement direction and the current movement direction are different with respect to the X-axis (S3), if L or the current correction amount is a value other than 0 (
S4), a certain amount of correction (for example, the amount of correction for 3 pulses)
The correction unit 33X generates a dummy block whose X-axis movement amount is (S5), and the data from the dummy block is sent to the interpolation unit 32X (S6). Data from the interpolation section 32X (data from the dummy block) is applied to the motor 42, the pole screw 46 is rotated by a predetermined angle within a range where the processing table 50 does not move, and dead zone correction is performed with respect to the X-axis.

Then, the data received from the NC program decoder 20 (
original movement data) is sent to the interpolation unit 32X (S7),
Based on this data, the motor 42 rotates, and the processing table 50 performs its original movement via the pole screw 46.

Then, it returns to SL, and the operations from 81 to S7 are repeated.
When there is no remaining NC program (S8), the above operation is ended.

In the embodiment described above, the correction amount for three pulses is set as the constant correction amount, but the correction amount is determined according to each dead zone.

According to the embodiment described in E, the original movement amount of the predetermined axis (movement command amount written in the NC program) and the correction amount for correcting the dead zone are controlled separately, so that the dead zone can be corrected accurately. Therefore, the shape accuracy can be improved.

:Figure 53 is a flowchart showing the operation of the X axis, but 2
Regarding other axes such as the Y-axis and the X-axis, the operation is similar to that shown in FIG. 3.

FIG. 4 is a flowchart collectively showing the operations of a plurality of axes in the above embodiment.

First, data is received from the NC program decoder 20 (S
ll), Analyze and store the movement amount and movement direction for each axis (S12), and judge for all axes whether the movement direction of the 8 axes is the same for the previous movement and this movement. In S13), if even one axis has different moving directions, it is determined whether or not correction is necessary for the axes with different moving directions (S14). If there is a value other than O, a dummy block is generated that moves only the axes that need to be corrected by a predetermined correction amount (S l 5).In other words, the correction amount becomes O for axes that do not need to be corrected. For axes that do not need to be corrected, the movement of those axes is stopped for a predetermined period prior to the current movement. In other words, the timing is matched between the axis on which dead zone correction is performed and the axis on which dead zone correction is not performed.

Then, the data from the dummy block is sent to the interpolation unit of the required axis (S l 6), and the dead zone is corrected.
The data received from the NC program decoding section 20 is sent to each interpolation section (S17), the original movement is performed, and the operation of S11-317 is repeated, and if there is no remaining part in the NC program (S18), the above Finish all operations.

In addition, in FIG. 1, only the control section g1 for the x, y, and z axes is shown, but in addition to this, control sections a for other axes such as the U axis and the ■ axis may be provided. .

[Effects of the Invention] According to the present invention, it is possible to reliably correct the dead zone, and therefore the shape accuracy can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing an example of the X-axis drive section in the above embodiment. FIG. 3 is a flowchart showing the operation regarding the X-axis in the above embodiment. FIG. 4 is a flowchart collectively showing the operations of a plurality of axes in the above embodiment. 20... NC program decoding section, 3 1 x, Y, Z... Movement direction comparison section, 32X, 32Y, 32Z... Interpolation section, 33X, 33Y, 33Z. ...Correction section.

Claims (2)

[Claims] (1) An NC program analysis section; A moving direction comparison section that compares the current moving direction and the previous moving direction with respect to a predetermined axial direction; A dead zone correction device for an electrical discharge machine, comprising: a correction unit that generates a dummy block that moves the predetermined axis by a certain correction amount prior to the current movement when the values are different; (2) In claim (1), when the current movement direction and the previous movement direction are the same with respect to the predetermined axial direction, the correction unit performs the correction for a predetermined period of time prior to the current movement. A dead zone correction device for an electric discharge machine, characterized in that the device stops movement of a predetermined axis.