JPH0410643B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a numerically controlled machine tool that moves a movable element such as a table with respect to an origin, and to control the start and stop of the numerically controlled machine tool. Regarding a control device.

<Prior Art> In general, in this type of numerically controlled machine tool, movable elements such as a table may become misaligned with respect to the origin due to various factors while the machine is stopped. If this positional deviation occurs, the control device will be unable to detect the relative position of the table with respect to the origin, and if the movable element is automatically returned to the origin in such a state, it may cause a collision between the workpiece and the tool, etc. Therefore, the return to origin is performed manually.

However, this method requires the operator to operate the machine while directly monitoring it, and it takes time to operate, especially when using an FMS that consists of a large number of machine tools.
etc., it is necessary to perform an operation to return to the origin for each machine tool and also for each control axis, which is a major factor in reducing the operating rate.

For this reason, conventionally, in addition to the origin detection device, an origin confirmation device is used. This uses a long dock and a switch to detect when a movable element is stopped within a certain width range relative to the origin, and as mentioned above, it detects slight positional deviations while the operation is stopped. Even if this occurs, the position of the movable element can be detected as long as it does not deviate from its origin zone. Therefore, when starting up a numerically controlled machine tool, the movable element is moved in a fixed direction, and as soon as it leaves the origin zone, it is moved in the opposite direction until the origin is detected, so that the return-to-origin operation can be performed automatically. . Since this return-to-origin operation moves the origin zone in advance in a certain direction and by a certain amount as a reference point, there is no risk of collision, and manual return-to-origin operation is not required, greatly improving the operating rate of the machine. can.

However, the conventional method described above requires an extra origin zone confirmation device, resulting in high cost, and has the disadvantage that it cannot be applied to existing machines without modifying the machine.

<Object of the Invention> The present invention has been made in order to eliminate these conventional drawbacks, and its purpose is to automatically return to the origin without providing an extra origin zone confirmation device. That's true.

<Structure of the Invention> The present invention has been made to achieve the above object, and FIG. 1 shows an overall configuration diagram showing an outline of the apparatus of the present invention. As is clear from this figure, in the present invention, a table or the like can be moved based on an origin detected by an origin detection device 25 by inputting a command signal from a numerical control device 11 to a feeder including a drive motor 21. This is a start/stop control device used in a numerically controlled machine tool 10 that moves an element 20, and the numerical control device 11 is configured to move the movable element 20 in a fixed direction with respect to the origin when the machine stops operating. The present invention is characterized in that it is provided with a shift means 17 for shifting a fixed amount in a fixed amount, and a return-to-origin means 18 for moving toward the origin in a direction opposite to the shift direction when the machine is started.

<Examples> Examples of the present invention will be described below based on the drawings. As shown in FIG. 2, the apparatus of the present invention includes a large number of numerically controlled machine tools 10 and
The computer 12 is comprised of a numerical control device 11 that controls 0 based on a preprogrammed program, and a computer 12 that controls the numerical control device 11 in general. This numerical control device 11 and computer 12
are connected to each other via interfaces 13, 14 and a transmission line 15, and necessary program data is transferred in response to a request from the numerical control device 11.

On the other hand, the numerically controlled machine tool 10 has a movable element 20 such as a table, a saddle, etc., and the movable element 20 is fed in the Z-axis direction by a feed device 22 including a servo motor 21. Although this numerically controlled machine tool 10 has a plurality of control axes such as an X-axis, a Y-axis, etc. in addition to the Z-axis, only one axis is shown for convenience of explanation. Furthermore, this numerically controlled machine tool 10 is equipped with an origin detection device 25. This origin detection device 25 consists of a dog 26 and a proximity switch 27, and the position where these two face each other is set as the origin P1, and by controlling the movement of the movable element 20 with this origin P1 as a reference, the movable element 20 can be moved with high precision. Can be positioned.

An input/output terminal 31 such as a teletype and a memory 32 such as a magnetic disk are connected to the computer 12 via a bus line 30. As shown in FIG. 3, this memory 32 stores machining programs MP corresponding to various types of workpieces, as well as machining programs MP that move the movable element 20 in a fixed direction with respect to the origin P1 when the numerically controlled machine tool 10 is stopped. A fixed quantity shift program SP for shifting to P1, and an origin return program RP for returning the movable element 20 to the origin P1 when starting up the numerically controlled machine tool 10 are stored, and by specifying a predetermined memory address, the computer 12 executes the corresponding program. It is read out and transferred to the numerical control device 11.

Next, stop and start control of the numerically controlled machine tool 10 in the above configuration will be explained. Although this embodiment includes a large number of numerically controlled machine tools 10, one numerically controlled machine tool 10 will be described here for convenience of explanation. FIG. 7 shows a state in which the preparation for operation has been completed, and when a start command is output from this, the processing routine shown in FIG. 4 is executed.

In the first step 100 in this routine, it is determined whether or not there is an abnormality, and if an abnormality is found, in step 101, the numerical control machine tool 10 of the day is checked.
A schedule program for the operation of the vehicle is read, and then in step 102 it is determined whether the schedule is complete. In this state, the daily schedule of the numerically controlled machine tool 10 has not been completed, so the process proceeds to step 105, and the machining program necessary for machining the workpiece is executed.
MP is searched, and the machining program MP is transferred to the numerical control device 11 in step 106.

On the other hand, on the numerical control device 11 side, at the same time as the machining program MP is transferred from the computer 12, step 301 of the processing routine shown in FIG. 6 is executed, and the machining program MP is read.
At this time, the program has not yet been edited, and since this program is a machining program MP, step 308 is executed after passing through steps 302, 303, and 305, and the servo motor 21 of the numerically controlled machine tool 10 is pulse distribution in one direction, so that the movable element 20
The workpiece that has been fed forward to the processing position P3 shown in the figure is processed. Step 3 after pulse distribution
From 09, the process returns to step 301 again, the next block data is read, and the process proceeds to step 3 in the same way as above.
Step 308 is executed after passing through steps 02, 303, and 305, and the servo motor 2 of the numerically controlled machine tool 10
1 in the + direction, and the movable element 20 is retreated to the origin P1 where the origin signal is output from the origin detection device 25, as shown in FIG.

Thereafter, by sequentially reading the machining program MP block by block and repeating the above steps, the movable element 20 sequentially machining the workpiece with feed control based on the origin P1. Thereafter, at the same time as the machining of this workpiece is completed, the end of the program is confirmed in step 302, and therefore, in step 310, the numerical control device 11 outputs an interrupt signal to the computer 12. Upon receiving this signal, the computer 12 executes step 101, reads the next schedule data of the numerically controlled machine tool 10, and based on this schedule, searches for the machining program MP corresponding to the workpiece to be machined next. This machining program is similar to the above.
The MP is transferred from the computer 12 to the numerical control device 11, and the numerically controlled machine tool 10 processes the next workpiece.

In this way, the workpiece is machined repeatedly, and when the daily schedule is completed, Step 10
2, the process proceeds to step 103, where a quantitative shift program SP is searched, and then, in step 104, the quantitative shift program SP is transferred to the numerical control device 11. Therefore, the numerical control device 11
On the side, the quantitative shift program SP is read in step 301, and the process proceeds to step 303 via step 302. This step 303
Then, based on the quantitative shift program SP, a fixed amount of shift pulses are sent from the numerical control device 11 to the numerically controlled machine tool 10. As a result, as shown in FIG. 7, the movable element 20 is positioned at a shift position P2 that is shifted by L in the - direction from the origin P1 as a reference, and in this state, the operation of the numerically controlled machine tool 10 is stopped.

The next day, when the numerically controlled machine tool 10 is to start operating again, step 200 of the routine shown in FIG. The home return program RP is transferred to the numerical control device 11. Therefore, on the numerical control device 11 side, after reading this origin return program RP in step 301, the program proceeds to step 305 via steps 302 and 303. In this step 305, based on the home return program RP, a pulse in the + direction is sent from the numerical control device 11 to the servo motor 21 of the numerically controlled machine tool 10, and as a result, the movable element 20
moves in the + direction, and at the same time the origin detection device 25 confirms the origin P1, the servo motor 2
1 is stopped, and the movable element 20 is returned to the origin P1. This completes the preparation for operation of the numerically controlled machine tool 10, and thereafter the numerically controlled machine tool 10 is controlled to be fed based on the origin P1 at the same time as the start of operation.

Note that when performing this return-to-origin operation, the movable element 20 is stopped at a shift position P2 that is shifted in the negative direction by L from the origin P1, so by moving the movable element 20 in the + direction from this shift position P2, The movable element 20 can be reliably returned to its origin without interfering with other devices.

In addition to the above-mentioned embodiment in which the fixed amount shift program SP is read and the movable element 20 is positioned at the shift position P2 shifted by L from the origin P1 at the end of the daily schedule, for example, the workpiece The movable element 20 may be positioned at the shift position P2 even if an abnormality signal is output during processing.

In other words, when this abnormal signal is output,
Steps 108, 109, 110, 10 in Figure 4
3, 104 is executed, whereby the home return program RP and quantitative shift program SP are transferred from the computer 12 to the numerical control device 11. Therefore, the numerically controlled machine tool 10 interrupts the machining operation and proceeds to steps 301, 302, 303,
Steps 305, 306, and 307 are executed to perform a return-to-origin operation, and steps 301, 302, 303, and 304 are executed based on the quantitative shift program SP to perform a shift operation. By performing these two operations, even if an abnormality occurs in the numerically controlled machine tool 10, the movable element 20 can be shifted to the position P2.
The shift position P2 can be used as a reference to perform a return-to-origin operation when restarting the next operation.

Furthermore, while the machine is stopped, the positional deviation of the movable element 20 is extremely small, and the positional deviation does not exceed the shift amount L, but due to some factor, the movable element 20 may be displaced in the + direction by more than the shift amount In this case, the origin P1 cannot be detected and the movable element 20 will overstroke.

To prevent such a situation, it is recommended to add step 311 after step 307 as shown in FIG. That is, in step 311, it is determined from the number of pulses sent whether or not the movable element 20 has moved by L+ΔL from the shift position P2 during the return-to-origin operation, and if the movable element 20 has moved more than the above-mentioned amount of movement, an abnormality signal is generated. is delivered and its operation is stopped, and overstroke of the movable element 20 can be prevented.

<Effects of the Invention> As detailed above, the apparatus of the present invention includes a numerical control device that includes a shift means that shifts a movable element by a fixed amount in a fixed direction with respect to the origin when the machine is stopped, and a shift means that shifts the movable element by a fixed amount in a fixed direction with respect to the origin when the machine is started. Since the configuration is provided with a return-to-origin means for moving the moving element in the opposite direction to the shift direction, the return-to-origin operation can be performed based on a shift position that is in a fixed relationship from the origin, and as a result, This has the advantage that there is no collision with other devices, and the return to the origin can be performed automatically without providing an extra origin zone confirmation device.

[Brief explanation of drawings]

Fig. 1 is an invention configuration diagram showing in a block diagram the components of the inventive concept of a start/stop control device for a numerically controlled machine tool according to the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, and Fig. 3 6 is a diagram showing the contents of the program stored in the memory, FIGS. 4 and 5 are flow charts showing the operation of the computer,
The figure is a flowchart showing the operation of the numerical control device.
FIG. 7 is an explanatory diagram showing the moving state of the movable element, and FIG.
The figure is a flowchart showing another embodiment of the invention. DESCRIPTION OF SYMBOLS 10... Numerical control machine tool, 11... Numerical control device, 17... Shifting means, 18... Origin return means, 2
0...Movable element, P1...Origin, P2...Shift position.

Claims (1)

[Claims] 1. In a numerically controlled machine tool, a movable element such as a table is moved with reference to an origin detected by an origin detection device by inputting a command signal from a numerical control device to a feeder including a drive motor, The numerical control device includes a shift means that shifts the movable element by a fixed amount in a fixed direction with respect to the origin when the machine is stopped, and a shift means that moves the movable element in a direction opposite to the shift direction toward the origin when the machine is started. 1. A start/stop control device for a numerically controlled machine tool, characterized in that it is provided with a home return means.