JPH07281720A - Coordinate error detecting system - Google Patents

Abstract

PURPOSE:To provide the coordinate error detecting system for a numerical controller so as to detect the error of machine coordinates caused by the fault of a work program to command move with an incremental dimension. CONSTITUTION:A work program 1 contains a coordinate error detecting command. A preprocessing arithmetic means 2 decodes the work program 1 and outputs a coordinate error detecting command and a moving command for a machine tool. A machine coordinate calculating means 3 judges whether the coordinate error detecting command is executed for the first time or after the second time and calculates the machine coordinate of the machine tool. A coordinate storage means 4 stores the machine coordinate in the case of the first coordinate error detecting command as a reference coordinate. A coordinate comparing means 5 compares the machine coordinate in the case of the coordinate error detecting command after the second time with the reference coordinate. When the machine coordinate is not matched with the reference coordinate, the execution of the work program is finished. Thus, since processing can be finished when there is any fault in the work program, it is not necessary to fix a position at a work starting point each time one work is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate error detection method for a numerical control device, and more particularly to a coordinate error detection method for a numerical control device that repeatedly executes a machining program that gives a movement command in incremental dimensions.

[0002]

2. Description of the Related Art Incremental dimension command is a method for commanding the movement of a tool when a numerical controller performs machining. The incremental dimension command is a command method that represents a target position by the amount of movement from the current position.

FIG. 6 is a diagram showing processing by an incremental dimension command according to a conventional method. this is,
In the case where the workpiece 7a is turned by the tool 8a, the movement between the points (P10, P11, P12, P13, P14) is commanded by the incremental dimension.

First, the machining start point P10 to point P11 is moved by fast-forwarding. The cutting of the work 7a is started from this point P11. Linear interpolation is performed from point P11 to point P12. Circular interpolation is performed from point P12 to point P13. Point P
13, linear interpolation is performed up to point P14. Finally, positioning is performed at the processing start point P10, and the cutting of the work 7a is completed. When the work 7a has been cut, the bar feeder replaces it with the next work, and the new work is processed by the same cutting path.

As described above, the numerical control device repeats the same machining, and the work can be machined one after another by exchanging the work by the bar feeder every one cycle of the machining.

[0006]

However, in the conventional numerical control device, the tool had to be returned to the machining start point after each machining cycle. Therefore, it takes an extra time to cut one work, which deteriorates the processing efficiency. The more workpieces to be machined, the worse the machining efficiency becomes.

Although it is possible to improve the machining efficiency by making it possible to continue cutting without returning the tool to the machining start point,
If there is an error in the machine coordinates due to a programming error when instructing the incremental dimension, the error will be accumulated by repeatedly executing it. Then, the deviation of the machine coordinates becomes large, and the dimension of the work after cutting becomes incorrect. Therefore, it is not possible to continue cutting without returning the tool to the processing start point, and it is necessary to perform positioning at the processing start point every cycle.

As described above, when cutting is continued without returning the tool to the machining start point, if there is an error in the machine coordinates due to an error in the machining program, the error accumulates and a defective work piece occurs. I will end up. And there was no means to detect the mistake of the machining program. Therefore, there is a problem that the tool cannot be continuously cut without returning to the machining start point.

The present invention has been made in view of the above circumstances, and provides a coordinate error detection method for a numerical control device capable of detecting an error in a machine coordinate due to an error in a machining program that gives a movement command in the incremental dimension. The purpose is to

[0010]

In order to solve the above problems, the present invention includes a coordinate error detection command in a coordinate error detection method of a numerical control device that repeatedly executes a machining program that gives a movement command in incremental dimensions. When the preprocessing operation means for decoding the machining program and outputting the coordinate error detection command and the tool movement command and the coordinate error detection command are output, whether the coordinate error detection command is the first time or the second time or later. Machine coordinate calculation means for calculating the machine coordinate of the tool, the coordinate storage means for storing the machine coordinate at the time of the first coordinate error detection command as the reference coordinate, and the second and subsequent coordinate errors. The machine coordinates at the time of the detection command are compared with the reference coordinates, and when the machine coordinates do not match the reference coordinates, the execution of the machining program is terminated. Coordinate error detection method characterized by having a standard comparator, is provided.

[0011]

The machining program includes a coordinate error detection command. The preprocessing calculation means decodes the machining program and outputs a coordinate error detection command and a tool movement command. The machine coordinate calculating means determines whether the execution of the coordinate error detection command is the first time or the second time and thereafter, and calculates the machine coordinate of the tool. The coordinate storage means stores the machine coordinate at the time of the first coordinate error detection command as the reference coordinate. The coordinate comparison means compares the machine coordinates at that time with the reference coordinates at the second and subsequent coordinate error detection commands. Then, when the machine coordinates and the reference coordinates do not match, the execution of the machining program is ended.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the present invention. The machining program 1 is programmed to repeatedly perform machining with the incremental dimension command, and includes a coordinate error detection command.

The preprocessing operation means 2 decodes the machining program 1, outputs a coordinate error detection command to the machine coordinate calculation means 3, and outputs an axis movement command to the interpolation means 6. Interpolation means 6
Receives the movement command, performs interpolation processing, and outputs an interpolation pulse. The axis control circuit 18 outputs a movement command to the servo amplifier 19 according to the interpolation pulse, and the servo amplifier 19 drives the servo motor 24 according to the command. Although only one axis control circuit 18, one servo amplifier 19 and one servo motor 24 are shown in the figure for easy understanding of the description, each axis is actually provided for each moving axis.

Upon receiving the coordinate error detection command, the machine coordinate calculation means 3 obtains the machine coordinate at that time. That is,
Since the tool is moved by the incremental dimension command, the machine coordinates at that time are not specified in the machining program. Therefore, the current machine coordinates are obtained by adding all the values of the incremental dimension from the processing start point. Further, it is determined whether the coordinate error detection command has been executed for the first time or after the second time.

The coordinate storage means 4 stores the machine coordinates obtained by the preprocessing operation means 2 when the coordinate error detection command is executed for the first time. The stored machine coordinates are used as reference coordinates. The coordinate comparison means 5 compares the machine coordinates obtained by the preprocessing operation means 2 with the reference coordinates when the coordinate error detection command is executed for the second time and thereafter. If they do not coincide with each other as a result, the execution of the machining program 1 is terminated for the preprocessing operation means 2, and at the same time, an output command of an alarm message is output to the graphic control circuit 15. Upon receiving the alarm message output command, the graphic control circuit 15 displays the alarm message on the display device 16.

FIG. 2 is a schematic block diagram of the hardware of the numerical controller for implementing the present invention. Processor 11
Controls the entire numerical controller according to the system program stored in the ROM 12. The RAM 13 stores a machining program, various data, and reference coordinates.
The non-volatile memory 14 stores parameters, pitch error correction amounts, tool correction amounts, etc. that should be retained even after the power is turned off.

The graphic control circuit 15 converts the digital signal into a signal for display and gives it to the display device 16. A CRT or a liquid crystal display device is used as the display device 16. The display device 16 displays a shape, a machining condition, an alarm message when a coordinate error is detected, and the like when the machining program is created interactively. The keyboard 17 is composed of symbolic keys, numerical keys, etc., and necessary graphic data and NC data are input using these keys. The graphic control circuit 15, the display device 16, the software key 23, and the keyboard 17 are used for CRT /
The MDI device 25 is configured.

The axis control circuit 18 receives an axis movement command from the processor 11 and outputs the movement command to the servo amplifier 19
Output to. The servo amplifier 19 receives the movement command and drives the servo motor of the machine tool 20. These components are coupled to each other by a bus 21.

The programmable machine controller (PMC) 22 uses the bus 21 when executing the NC program.
Receives T function signal (tool selection command) etc. via. Then, this signal is processed by the sequence program, a signal is output as an operation command, and the machine tool 20 is controlled.
Further, it receives a status signal from the machine tool 20, performs a sequence process, and transfers a necessary input signal to the processor 11 via the bus 21.

FIG. 3 is a view showing an example of machining a work according to the present invention. This is a turning process, and in this figure, between points (P0 to P1, P1 to P2, P2 to P3, P3 to P).
4, P4-P5, P5-P6, P6-P1) movement of the tool 8 is an incremental dimension command.
The tool 8 moves from the machining start point P0 to the point P1 by rapid feed, and then the cutting of the work 7 is started from the point P1. The points P1 to P2 are linearly interpolated, the points P2 to P3 are circularly interpolated, and the points P3 to P4 are linearly interpolated. And the point P
When the coordinate error detection command is issued after moving from 4 to the point P5 by fast-forwarding, the machine coordinate of the point P5 is calculated and the RAM 13
(Shown in FIG. 2). The stored coordinates are the reference coordinates. After that, it moves fast to point P6 and then to point P1. During this time, the work 7 is exchanged for the next work by the bar feeder. This completes the first cycle.

In the second cycle, P1 to P5 are the same as the first cycle. Then, when the coordinate error detection command is issued after moving to the point P5, the machine coordinate of the point P5 is calculated. Then, the calculated machine coordinates are compared with the reference coordinates. If they match as a result of the comparison, the machining is continued. On the contrary, if they do not match, the processing is finished.

FIG. 4 is a diagram showing an example of a machining program for carrying out the present invention. This machining program 1 is a program for performing the machining shown in FIG. 3, and in this example, “G51” is the coordinate error detection command. The amount of movement between the points in FIG. 3 (the amount of movement in the X-axis direction, the amount of movement in the Z-axis direction) is as follows. Point P0 → point P1 (a ₁ , b ₁ ). Point P1 → Point P2 (0, b ₂ ). Point P2 → point P3 (a ₃ , b ₃ ). Point P3 → point P4 (a ₄ , b ₄ ). Point P4 → point P5 (a ₅ , 0). Point P5 → point P6 (0, b ₆ ). Point P6 → Point P1 (a ₇ , 0). Further, the radius of the circular arc from the point P2 to the point P3 is “r ₀ ”.

This machining program 1 starts from the block with the sequence number N020 to the sequence number N09.
The block having the sequence number N060 is a coordinate error detection command.

In the block of sequence number N010, the tool 8 is moved from the machining start point P0 to the point P1 (Ua ₁ , Wb).
Move to ₁ ) by fast forward (G00). In the block of sequence number N020, from point P1 to point P2 (Wb ₂ )
Cutting feed is performed by linear interpolation (G01). Feed rate is 3
It is 0 mm / min.

Block with sequence number N030
And from point P2 to point P3 (Ua₃ Wb ₃) To circular interpolation
Cutting feed is performed in (G02). The radius of the arc is r₀(Rr
₀).

Block of sequence number N040
And from point P3 to point P4 (Ua_Four Wb _Four) To linear interpolation
Cutting feed is performed at (G01). Sequence number N0
In blocks of 50, points P4 to P5 (Ua_FiveFast forward to
Move with R (G00).

A coordinate error detection command (G51) is issued in the block of sequence number N060. Point P5 to point P6 in the block of sequence number N070
Move to (Wb ₆ ) by fast forward (G00).

In the block with the sequence number N080, it moves from point P6 to point P1 (Ua ₇ ) by fast forward (G00). In the block of sequence number N090,
Jump to the block with sequence number N020 (G
OTO 020).

The block (M99) of the sequence number N100 is a command for returning to the program that called this machining program. FIG. 5 is a flowchart showing the processing procedure of the present invention. This flowchart is shown in Figure 1.
This will be described with reference to the block diagram of FIG.

In step 1, when the preprocessing operation means 2 decodes the machining program 1 and outputs a coordinate error detection command,
The machine coordinate calculation means 3 determines whether the execution of the machining program 1 (judgment based on the number of executions of the coordinate error detection command) is the first time or the second time or later. If the first time, the process proceeds to step 2 and the second time or later. In the case of, go to step 5.

In step 2, the machine coordinate calculating means 3 calculates the machine coordinate of the tool when the coordinate error detection command is output. In step 3, the coordinate storage means 4 executes step 2
The machine coordinates calculated in step 1 are stored as reference coordinates.

At step 4, the preprocessing operation means 2 decodes the machining program, and if all the workpieces have been machined, the machining is terminated, and if not, the machining is continued and the process proceeds to step 1.

In step 5, the machine coordinate calculating means 3 calculates the machine coordinate of the tool when the coordinate error detection command is output. In step 6, the coordinate comparison means 5 executes step 3
The reference coordinates stored in the coordinate storage means 3 are compared with the machine coordinates calculated in step 5. If they match, the process proceeds to step 4, and if they do not match, the process proceeds to step 7.

In step 7, the coordinate comparison means 5 outputs an alarm message to the display device 16, and further causes the preprocessing calculation means 2 to stop the execution of the machining program 1, thereby ending the processing.

In this way, when the machining program with the incremental dimension command is repeatedly executed, the machine coordinates are stored as the reference coordinates at a predetermined location during the first execution, and the second and subsequent executions are performed. In this case, the machine coordinates and the reference coordinates at the same place are compared, so that it is possible to detect the deviation of the movement distance due to an error in the machining program due to the incremental dimension command and find the error. The operator can confirm that there is an error in the machining program by the alarm message displayed on the display device. Further, when the deviation of the movement distance is detected, the execution of the machining program is immediately ended, so that the occurrence of a defective work can be prevented. This eliminates the need to return the tool to the machining start point every time one workpiece is machined when performing repetitive machining, and the machining can be speeded up.

In the above description, the machine coordinates are compared with the reference coordinates and the processing is terminated if they do not match. However, an error tolerance range is provided, and the absolute value of the difference between the machine coordinates and the reference coordinates is the error tolerance range. If it is within the range, the processing can be continued. For example, the allowable range is set to 0.01 mm and the process is continued when the error between the machine coordinates and the reference coordinates is 0.01 mm or less.

When the allowable range of the error is set, the error between the machine coordinate and the reference coordinate is accumulated every time the machining is repeated,
Eventually it will exceed the allowable range. However, when the allowable range is 0.01 mm and the error caused by programming error is 1 μm, 10 loops are required until the allowable range is exceeded. If the number of workpieces to be machined is 10 or less, there is no need to modify the machining program.

As described above, by providing the allowable range of the error, it is possible for the operator to avoid unnecessary modification work of the machining program, and to shorten the time spent for creating the machining program.

[0039]

As described above, according to the present invention, when the machining program with the incremental dimension command is repeatedly executed, the machine coordinates are stored as the reference coordinates at a predetermined location when the machining program is executed for the first time. At the time of the second and subsequent executions, the machine coordinates at the same place at that time,
Since it compares the reference coordinates stored in the first time and ends the process if they do not match, it is possible to find the error in the machine coordinates due to an error in the machining program and prevent the occurrence of defective work. You can Therefore, it is possible to perform repeated machining without returning the tool to the machining start point every time one workpiece is machined.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of the present invention.

FIG. 2 is a schematic configuration diagram of hardware of a numerical control device for carrying out the present invention.

FIG. 3 is a diagram showing an example of processing a work according to the present invention.

FIG. 4 is a diagram showing an example of a machining program for implementing the present invention.

FIG. 5 is a flowchart showing a processing procedure of the present invention.

FIG. 6 is a diagram showing processing by an incremental dimension command according to a conventional method.

[Explanation of symbols]

 1 Machining program 2 Pre-processing calculation means 3 Machine coordinate calculation means 4 Coordinate storage means 5 Coordinate comparison means 6 Interpolation means 15 Graphic control circuit 16 Display device 18 Axis control circuit 19 Servo amplifier 24 Servo motor

Claims (2)

[Claims] 1. A coordinate error detection method for a numerical controller that repeatedly executes a machining program that issues a movement command with an incremental dimension. The machining program including the coordinate error detection command is decoded to move the coordinate error detection command and the tool. When a coordinate error detection command is output, a pre-processing operation unit that outputs a command and a machine coordinate calculation that determines whether the coordinate error detection command is the first time or the second time and the machine coordinate of the tool are calculated. Means for storing the machine coordinates at the time of the first coordinate error detection command as reference coordinates, and comparing the machine coordinates at the time of the second and subsequent coordinate error detection commands with the reference coordinates. And a coordinate comparing means for terminating the execution of the machining program when the machine coordinate and the reference coordinate do not match. Out method. 2. The coordinate comparing means ends the execution of the machining program when the error between the machine coordinate and the reference coordinate at the second and subsequent coordinate error detection commands exceeds a preset value. The coordinate error detection method according to claim 1, wherein the coordinate error detection method is performed.