JPH11143514A - Numerical controller capable of executing working error check - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a numerical controller which preliminarily verifies a work error without working a work. SOLUTION: A program is executed by idling (S1 and S2) without working a work after plotting a program path. Synthetic position deviation E is calculated from each axial position deviation (S3). An actual tool route is obtained by changing the kinds of lines between when the deviation E exceeds set limitation value E0 and when it does not and plotting a detected tool current position. It is possible to know that a working error is large because a plotting line kind is different when the deviation E exceeds the value E0 in an actual tool route. A different line kind is not plotted by supervising the plotting image and adjusting a working condition, that is, it is possible to adjust a working condition that becomes the deviation E in the value E0 by supervising the plotting image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical controller capable of verifying in advance a machining error in machining by a machine tool controlled by the numerical controller.

[0002]

2. Description of the Related Art A conventional numerical controller with a built-in computer (hereinafter referred to as CNC) has a function of displaying a programmed tool path graphically. There is no means to verify that

[0003]

In machining with a machine tool utilizing CNC, a servomotor is used as a drive source for moving a tool relative to a work. There is a delay in a servo system that drives and controls this servomotor, and a position error due to the delay and a processing error due to acceleration / deceleration occur. By reducing these positional deviations,
Various methods and means have been developed to reduce machining errors.However, as a result of executing a machining program in the end, it is necessary to verify which part of the machined workpiece is not machining accurate. There is no other method than to measure the shape of the actually processed work. Therefore, in order to obtain the target processing accuracy, the processing conditions (particularly the processing speed)
There is no other way but to repeat machining and shape measurement until the target machining accuracy is obtained while changing a lot of work, wasting a lot of work and wasting time and labor. There was a problem.

An object of the present invention is to provide a CNC which can solve the above-mentioned drawbacks of the prior art and can verify a processing error in advance.

[0005]

According to the present invention, a machining program is executed in idle operation without machining a workpiece, and an actual tool path obtained at that time is drawn on a display device, or a position deviation obtained at that time is displayed. Processing errors can be checked by drawing on the device. In addition, the processing error can be checked by drawing the actual tool path by changing the line type only in the section where the position deviation exceeds the set limit value. At the time of drawing, the check is facilitated by drawing the program path of the machining program on the same screen.

In addition, the position deviation is monitored, and only the blocks of the processing program having a command in which the position deviation exceeds the set limit value are used to change the drawing line type to draw the processing program path on the display device. Check it.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of a CNC 10 according to an embodiment to which the present invention is applied and a machine tool driven and controlled by the CNC 10, for example, a milling machine or the like.

The processor 11 is a processor that controls the CNC 10 as a whole.
Is read, and the CNC 10 is entirely controlled in accordance with the system program. The RAM 13 stores temporary calculation data, display data, and the like. The CMOS memory 14 is backed up by a battery (not shown), is configured as a nonvolatile memory that retains a storage state even when the power of the CNC 10 is turned off, and stores a machining program.

An interface 15 is an interface for an external device, and includes an external device 72 such as a paper tape reader, a paper tape puncher, or a floppy disk driver.
Is connected. A processing program is read from a paper tape reader or a floppy disk and stored in the CMOS memory 14. In addition, the CM is edited in CNC10
The processing program stored in the OS memory 14 can be output to a paper tape puncher or a floppy disk driver.

A PMC (programmable machine controller) 16 controls a machine tool by a sequence program built in the CNC 10. That is, according to the functions specified by the machining program, these sequence programs convert the signals into necessary signals on the machine tool side.
7 to the machine tool. Various actuators on the machine tool are operated by this output signal. Further, it receives signals from various switches and the like of a machine operation panel (not shown) provided with the limit switch on the machine tool side and the display / MDI 70, performs necessary processing, and passes the signals to the processor 11.

The present position of each axis, alarm, parameter,
An image signal such as image data is sent to the display device of the display / MDI unit 70 composed of a CRT, a liquid crystal or the like, and displayed on the display device. Interface 18 is display / M
The data from the keyboard in the DI unit 70 is received and passed to the processor 11. The interface 19 is connected to the manual pulse generator 71 and receives a pulse from the manual pulse generator 71. The manual pulse generator 71 is mounted on the machine operation panel on the machine tool side, and is used for manually positioning the movable part of the machine precisely.

The axis control circuits 30 to 32 receive the movement commands of the respective axes from the processor 11 and output the commands of the respective axes to the servo amplifiers 40 to 42. The servo amplifiers 40 to 42 receive the command and drive the servo motors 50 to 52 of each axis. The X, Y, and Z axis servomotors 50 to 52 have pulse coders for detecting position and speed, and the position and speed feedback signals from the pulse coder are fed back to the axis control circuits 30 to 32. Axis control circuit 3
Each of the servo control CPUs 0 to 32 performs each processing of a position loop, a speed loop, and a current loop based on these feedback signals and the above-described movement command, and executes a torque command for final drive control. Is obtained for each axis, and the positions and speeds of the servo motors 50 to 52 of each axis are controlled.

The spindle control circuit 60 outputs a spindle speed signal to the spindle amplifier 61 in response to a spindle rotation command and a command such as spindle orientation. Upon receiving the spindle speed signal, the spindle amplifier 61 rotates the spindle motor 62 at the commanded rotation speed. In addition, in accordance with an orientation command, the rotational position of the spindle motor 62 is positioned at a predetermined position based on a feedback signal from a position coder (not shown) for detecting a spindle position.

FIG. 2 is a processing flowchart executed by the processor 11 of the CNC 10 in one embodiment of the processing error check of the present invention. When a machining program execution command is input in the machining error check mode, the processor 11 reads the machining program stored in the CMOS 14 and displays the tool path designated by the machining program on the screen of the display device of the display / MDI 70. (Step S1). It is assumed that this tool path is, for example, a path indicated by a symbol P in FIG. Next, the processor 11 reads the program from the beginning of the machining program, and starts executing the machining program in idle operation without machining the workpiece (step S2).

The processor 11 outputs a distribution movement command (pulse) to the axis control circuits 30 to 32 of each axis based on the movement command specified by the program for each distribution cycle of the movement command, and outputs the axis control circuit of each axis. Numerals 30 to 32 perform position and speed loop processing based on a distribution movement command and a position and speed feedback signal fed back from a pulse coder, and further perform current loop processing to perform servomotor 50 of each axis via a servo amplifier. To 52 are moved to move the tool relatively to the table on which the work is mounted (note that the work is not mounted on the table so that the processing is not performed and the tool is idle). Then, the processor 11 sends the position feedback signal to the axis control circuit 30 to
32, the current position of each axis is obtained, and the detected current position is subtracted from the commanded position of each axis to obtain a position deviation. Further, the position deviation of each axis is combined to obtain a combined position deviation. For example, generally, a command for three-dimensional machining is assumed, and the positional deviation of each of the X, Y, and Z axes is ex, e.
y, ez, the combined position deviation E = (ex ² +
ey ² + ez ² ) ^1/2 (step S3). Next, it is determined whether or not the combined position deviation exceeds the set limit value E0 (step S4). That is, it is determined whether "E>E0".

If the combined position deviation E does not exceed the set limit value E0, a standard line type for drawing the actual tool path (a line type different from the program path drawn in step S1, for example, display color) , Change the line type such as a solid line or a broken line) (step S5), and draw up to the position detected in step S3 (step S6). In FIG. 3, the actual path Q is drawn by a thin line having a width smaller than the line width of the program path P. If the combined position deviation E exceeds the set limit value E0, a line type set as large error is selected (step S8), and step S3 is performed.
Is drawn up to the position detected in step (step S6). FIG.
In the figure, an example is shown in which the broken line is drawn when the combined position deviation E exceeds the set limit value E0.

Next, it is determined whether or not the program ends (step S).
7) If not completed, steps S3 to S7 are sequentially performed.
And the process of step S8 is repeatedly executed, and at the stage where the execution of the idling operation is completed until the end of the program, as shown in FIG. 3, the program path P and the actual tool path Q are drawn with different line types, and The composite position deviation E is equal to the set limit value E.
In the section exceeding 0, the actual tool path is drawn by another line type (broken line in FIG. 3).

By observing the drawn program path P and the actual tool path Q, if necessary, the drawn image is partially enlarged and drawn, and the combined position deviation E is set to the set limit value E0.
In some cases, such as when there is a section exceeding the limit, or when a satisfactory actual tool path Q cannot be obtained,
By changing the machining speed, the acceleration / deceleration time constant of the machining speed, and the like, the machining program is again executed in the idle running machining error check mode, and machining conditions are determined so that the combined position deviation E does not exceed the set limit value E0. Thus, it is possible to obtain processing conditions with a small processing error without actually processing the work.

FIG. 4 is a flowchart of a processing error check process according to the second embodiment of the present invention. In the second embodiment, instead of drawing the actual tool path, the drawing of the movement command of a block having a section where the combined position deviation E exceeds the set limit value E0 is performed with the line type of the drawing of another movement command. It is designed to draw with different line types.

When a machining program execution command is input in the machining error check mode, the processor 11
The machining program stored in the OS 14 is read from the beginning, and the execution of the machining program is started in idle operation without machining the work (step T1). One block is read (step T2), and it is determined whether it is a program end (step T3).
A combined position deviation E is obtained for each movement command distribution cycle similar to that in step S3 described above (step T4). Then, it is determined whether or not the combined position deviation E exceeds the set limit value E0 (step T5).
Then, if it exceeds, the flag F is set to "1" (step T6), and the process proceeds to step T7. Note that the flag F is set to “0” by default. In step T7, it is determined whether or not the distribution of the movement command for the block has been completed. If not, the process returns to step T4, where the above-described combined position deviation E is obtained for each distribution cycle, and the value exceeds the set limit E0. It is determined whether or not the flag F is set to "1" only when it exceeds the threshold value, and the processing of steps T4 to T7 is repeatedly executed.

When the distribution of the movement command of the block is completed, it is determined whether or not the flag F is set to "1" (step T8). The composite position deviation E is equal to the set limit value E.
If it does not exceed 0, a standard line type is selected (step T9), and a program path P for a movement command of the block is drawn with the selected line type (step T11). FIG.
It is a drawing example in this embodiment. Standard line types are represented by solid lines. If the combined position deviation E exceeds the set limit value E0 at least once and the flag F is "1", a line type having a large error is selected (step T13), and the movement command of the block is selected by the selected line type. Is drawn (step T11). In FIG. 5, a line type having a large error is indicated by a broken line.

Then, the flag F is set to "0", and the process returns to step T2 to start the processing of the next block. Hereinafter, the processing of steps T2 to T12 and T13 is executed for each block, and a program path as shown in FIG. 5 is drawn.
When the program end is read, the processing error check processing ends.

By observing the drawing of the program path obtained in this way, if there is a path of a block drawn with a line type (broken line) having a large error, processing conditions such as the feed speed of the block are adjusted, and a large error is generated. Until the drawing of the line type disappears, the program is executed by the idle operation of the machining error check to find out the optimal machining conditions.

FIG. 6 is a diagram showing a drawing state according to the third embodiment. The left side in FIG. 6 illustrates the program path P, and the right side in FIG. 6 illustrates the actual tool path Q. In the case of this embodiment, the difference from the processing of the first embodiment is that step S3 in FIG.
S5 and S8 are different, and only the actual tool path is drawn. That is, step S
At 1, the program path P is drawn as shown in FIG. 6, and then the program is started in idle operation (step S 2). At step S 3, only the current position that is fed back is obtained without calculating the position deviation. Find, step S
6, the obtained current position is plotted on the display screen of the display device and connected by a line. This processing is executed until the end of the program, and is drawn as the actual tool path Q in FIG.

The drawn program path P and the actual tool path Q are observed while being compared with each other, and if the actual tool path Q is greatly deviated from the program path P and a desired machining shape cannot be obtained, Adjust the processing conditions such as the processing speed and acceleration / deceleration time constant, execute the idle operation of the processing error check again to obtain the same actual tool path Q, and perform processing until a satisfactory actual tool path Q is obtained. Adjust the conditions.

Note that the processing shown in FIG. 2 may be executed, and the drawing position at the current position may be drawn in parallel as shown in FIG. 6 without overlapping with the program path as shown in FIG. In the case where the combined position deviation E exceeds the set limit value E0, the actual tool path Q is drawn with different line types as shown in FIG. Also, as shown in FIG.
Instead of drawing the program path P and the actual tool path Q in parallel, they may be drawn in an overlapping manner. In this case, if the drawing is performed by changing the line type (especially, color) of the program path P and the actual tool path Q, the shape error can be easily detected.

FIG. 7 is a diagram showing a drawing state according to the fourth embodiment. The left side of FIG. 7 illustrates the program path P, and the right side of FIG. 7 illustrates the combined position deviation E as a function of time. The processing in the fourth embodiment is the same as the processing flowchart in FIG. 2 until the combined position deviation E is obtained in step S3,
Thereafter, without performing the processing of steps S4, S5, S6, and S8, a process of plotting the combined position deviation E obtained for each distribution cycle as a function of time as shown in the position deviation graph of FIG. The process shifts to S7 to repeatedly execute this processing until the program ends. Then, a drawing as shown in FIG. 7 is obtained. If a line of ± E0 is drawn on the position deviation graph as the position deviation limit value, it can be immediately determined whether or not the position exceeds the limit value E0.

This position deviation graph is monitored, and the position deviation E
If there is a part where is large, change the processing conditions such as the processing speed and acceleration / deceleration time constant for the whole or the corresponding part, and execute the idle operation of the processing error check again to obtain the position deviation graph. The processing conditions may be adjusted until a satisfactory position deviation graph is obtained.

In each of the above embodiments, the processor 1
1 receives the feedback signal of the position indicating the current position of each axis via each of the axis control circuits 30 to 31 and subtracts the current position from the command position to obtain the position deviation of each axis. Is determined by the position loop control of each axis control circuit 30 to 31 (determined by a register or the like for determining a position deviation), the processor 11 may read out each axis position deviation.

[0030]

According to the present invention, it is possible to monitor the state of the position deviation due to the delay or acceleration / deceleration of the servo system without actually performing the processing, so that the processing error caused by the position deviation can be easily monitored. In addition, since the processing error due to the position deviation is drawn, it is not necessary to perform the operation of measuring the processing error, the processing conditions can be easily adjusted, and the optimum processing conditions can be obtained in a short time. Further, since the working is not actually performed, the work is not wasted.

[Brief description of the drawings]

FIG. 1 is a main block diagram of a CNC according to an embodiment of the present invention.

FIG. 2 is a flowchart of a processing error check process according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a drawing screen according to the first embodiment.

FIG. 4 is a flowchart of a processing error check process according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a drawing screen according to the second embodiment.

FIG. 6 is an explanatory diagram of a drawing screen according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of a drawing screen according to a fourth embodiment of the present invention.

[Explanation of symbols]

 10 Numerical control unit (CNC) 50, 51, 52 Servo motor 62 Spindle motor 70 Display / MDI P Program path Q Actual tool path

Claims (5)

[Claims] 1. A numerical control device capable of executing a machining program in idle operation without machining a workpiece, drawing an actual tool path obtained at that time on a display device, and performing a machining error check capable of checking a machining error. 2. A numerical control device capable of executing a machining program in idle operation without machining a workpiece, drawing a positional deviation obtained at that time on a display device, and performing a machining error check capable of checking a machining error. 3. A machining program is executed in idle operation without machining a workpiece, and an actual tool path obtained at that time is drawn on a display device. Numerical control device capable of checking a machining error that enables the checking of a machining error for drawing a tool path. 4. The numerical controller according to claim 1, wherein the program path of the machining program is drawn on the same screen. 5. A machining program which executes a machining program in idle operation without machining a workpiece, monitors a position deviation, and receives a command in which the position deviation exceeds a set limit value. Is a numerical control device capable of performing a processing error check by drawing a character on a display device so that the processing error can be checked.