JPS6262362B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a numerical control device, and particularly to a numerical control device capable of correcting a commanded machining trajectory.

In recent years, systems that control machine tools with numerical control devices and process materials (workpieces) into desired shapes have come into widespread use.

FIG. 1 is an explanatory diagram showing the concept of general numerical control. In the figure, 1 is a machining command tape with holes punched according to the desired machining order and dimensions according to predetermined rules, and 2 is a machining command tape 1. 3 is a numerical control device provided with the tape reader 2, and 4 is a machine tool controlled by the numerical control device 3.

Next, the operation will be explained.

By reading the information on the machining command tape 1 with the tape reader 2 of the numerical control device 3, the numerical control device 3 controls the machine tool 4 based on the information read with the tape reader 2.

As a result, the machine tool 4 can be moved via the numerical control device 3 as instructed by the machining command tape 1, and the workpiece can be machined into the desired shape and dimensions.

However, when machining workpieces that require precise dimensional accuracy, the problem is that it is not always possible to obtain the desired dimensional accuracy due to mechanical errors caused by the rigidity and mechanical precision of the machine tool itself. It was hot.

Therefore, it has been considered to provide conventional numerical control devices with functions for improving machining dimensional accuracy, such as a backlash correction function and a pitch error correction function.

This invention was made to solve the above-mentioned problems. For example, in a numerically controlled lathe that performs cutting, etc., as shown in FIG. Trajectory 2
When performing cylindrical cutting (axis-parallel or tapered) along 3, the actual machining trajectory 35 of the workpiece 34, as shown in FIG. Separately, another object of the present invention is to obtain a numerical control device that can correct the actual machining trajectory 35 by setting the cylindricity correction amount in advance before machining.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a schematic configuration diagram showing a numerical control device according to an embodiment of the present invention. In the figure, numeral 41 indicates a machining instruction tape having holes punched according to a predetermined rule in a desired machining order and dimensions, and 42 a tape. A reader 43 is a command movement amount register that stores a movement amount based on information read by the tape reader 42;
Reference numeral 44 indicates a command sequence number register that stores the sequence number read by the tape reader 42.

45 is a correction block sequence number setting section for setting a correction block sequence number; 46 is an X-axis correction amount setting section for setting an X-axis correction amount; 47
indicates a Z-axis correction position setting section that sets the Z-axis correction position, and each setting section 45 to 47 constitutes a setting device.

Reference numeral 48 indicates a coincidence detector, which compares the sequence number of the command sequence number register 44 and the correction block sequence number of the correction block sequence number setting section 45, and outputs a significant output signal 49 when they match, and outputs a significant output signal 49 when they do not match. An unexpected output signal 49 is output.

50, 51, 52 are command movement amount registers 43;
The data output signals 53 are output from the X-axis correction amount setting section 46 and the Z-axis correction position setting section 47, and a correction computing unit 53 indicates a significant output signal 49 from the coincidence detector 48. 52 to perform a predetermined calculation and calculate the corrected movement amount.

Reference numeral 54 indicates a corrected movement amount register that stores the corrected movement amount calculated by the correction calculator 53, and is composed of two register sections 54a and 54b.

55 is a movement data control circuit, and 56 is a machine tool including a servo portion.

Incidentally, FIG. 4 shows an example of a general lathe that is composed of two axes, an X axis and a Z axis.

FIG. 5 is a coordinate diagram showing the coordinate relationship of correction,
In the figure, P ₁ is the current position (starting point), P ₂ is the reached position (end point), P ₃ is the correction position, P ₄ is the correction command position, l ₁ is the normal command trajectory, and l ₂ is the machine-side factor. The locus deviated from the actually machined command locus _l1 , and _l3 indicates the corrected command locus.

Note that FIG. 5 is an example in which the number of correction positions on the Z axis is one point.

Next, the operation will be explained.

It is assumed that d is set as the correction block sequence number, x ₁ is set as the X-axis correction amount, and z ₁ is set as the Z-axis correction position in each setting section 45, 46, and 47.

Now, if the machining position of the machine tool 56, that is, the current position _P1 is set as the origin as shown in FIG. ₂ coordinate values (X ₁ , Z ₁ ) are sent to the command movement amount register 43, and the sequence number is sent to the command sequence number register 4.
4.

Then, the coincidence detector 48 compares the sequence number in the command sequence number register 44 with the correction block sequence number in the correction block sequence number setting section 45.

At this time, the command sequence number register 44
If the sequence number of is d, the coincidence detection circuit 4
8 outputs a significant output signal 49, the correction calculator 53 calculates the coordinate value of the correction command position P ₄ from the data of each data output signal 50 to 51, that is, X ₁ , Z ₁ , x ₁ and z ₁ , ((X ₁ /Z ₁・z ₁ +x ₁ ), z ₁ ) The coordinate value of the reached position P ₂ with the correction command position P ₄ as the starting point is converted to the register part 54a of the correction movement amount register 54, (X ₁ −X ₁ /Z ₁ ·z ₁ −x ₁ ), (Z ₁ −z ₁ )) and stored in the register section 54b.

On the other hand, if the sequence number in the command sequence number register 44 is other than d, the coincidence detector 48
outputs an unexpected output signal 49, the correction calculator 53 outputs the data X ₁ , Z ₁ without performing the above calculation.
is stored as is in the register section 54a.

As described above, the data stored in the register sections 54a and 54b is output from the register 54a to the movement data control circuit 55, so that the data is transferred to the machine tool 56 by the movement data control circuit 55.
The movable part of the machine tool 56, which is the controlled object, is driven and moved to the correction command position _P4 .

Then, the movable part of the machine tool 56 moves to the correction command position.
After completing the movement to _P4 , the data in the register section 54b is processed in the same way, and the movable part of the machine tool 56 completes the movement to the destination position _P2 .

As a result, the actual machining trajectory with respect to the correction command trajectory l ₃ becomes l ₄ , and it is possible to correct the deviation in cylindricity caused by factors on the machine tool side.

In the above embodiment, there is one correction position _P3 , but by using a plurality of setting devices and correction movement registers 54 each consisting of setting sections 45 to 47, there can be a plurality of correction positions. Can be done. Furthermore, the operations of the coincidence detector 48, correction calculator 53, and correction movement amount register 54 can be processed by software.

As described above, according to the present invention, machining errors caused by factors on the machine tool side can be corrected, and high machining dimensional accuracy can be obtained.

Therefore, when performing cylindrical cutting on a lathe, by correcting the position of the X-axis, which is not normally moved, it is possible to correct the bend in cylindricity caused by factors on the machine tool side, which is effective in machining high-precision parts. do.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the concept of general numerical control, Fig. 2 is an explanatory diagram showing the cutting command trajectory of two-axis control, and Fig. 3 is an example of the conventional cutting trajectory when machining is performed as shown in Fig. 2. FIG. 4 is a schematic configuration diagram showing a numerical control device according to an embodiment of the present invention, and FIG. 5 is a coordinate diagram showing the coordinate relationship of correction. In the figure, 41 is a processing command tape, 42 is a tape reader, 43 is a command movement amount register, 44 is a command sequence number register, 45 is a correction block sequence number setting section, 46 is an X-axis correction amount setting section, and 47 is a Z-axis A correction position setting section, 48 a coincidence detector, 53 a correction calculator, 54 a correction movement amount register, 55 a movement data control circuit, 5
6 indicates a machine tool.

Claims (1)

[Claims] 1 In numerical control devices that control machine tools,
A setting device for setting a correction block sequence number, a correction position of one block, and a correction amount at the correction position; a coincidence detector for comparing the sequence number of a command sequence number register with the correction block sequence number; and this coincidence detector. and a correction calculator that calculates a corrected movement amount using the corrected position and the corrected amount based on a coincidence detection output signal outputted by the numerical controller.