JPS61152351A - Machine tool with function of returning to original position - Google Patents

Abstract

PURPOSE:To obtain an unmanned machine tool by forming a machine tool in such a manner as a program of its returning to an original position is executed by numerical control through operating a control means for returning said unmanned machine to the original position on the basis of abnormality detection signal. CONSTITUTION:When load torque of a main shaft motor 18 exceeds the allowable value, a signal of abnormality detection from an abnormality detection circuit 19 is inputted to a sequence control device 3, which then sends a reset signal to a numerical control device 2 to discontinue a processing program in execution. Then, the top block a program of returning to the original position is sent out to the numerical control device 2 to give a command of program research. Subsequently, said control device 2 is started to execute the program of said return. By this structure, unmanned operation can be performed efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a machine tool equipped with a home position return function.

<Conventional technology> In a machining center type machine tool, the occurrence of a machining abnormality during machining is detected by an overload of the spindle motor, etc., and if a bending abnormality is detected, machining is stopped at the time the abnormality occurs. The process was interrupted, and the machine was then manually returned to its original position to replace the tool and eject the workpiece.

<Problems to be Solved by the Invention> As described above, in conventional machine tools, the return to the original position after interruption of machining must be performed manually, which makes it difficult to unmanned.

In particular, as shown in FIG.
If a machining abnormality is detected when the tool T cannot be moved to the axial direction, it is not possible to return to the original position by simply moving the tool T in the axial direction. I had to return to the original position.

<Means for Solving the Problems> Figure 1 is an overall configuration diagram for clearly demonstrating the present invention.The present invention involves moving a machining tool in the radial direction within a machining hole, and then returning it to its original position. A storage means A stores a program for returning to the original position for axial movement of the machine, an abnormality detection means B detects that an abnormality has occurred during machining, and an abnormality detection circuit detects that an abnormality has been detected. The present invention is characterized by comprising a home position return control means C for causing the numerical control means to execute the home position return program in response.

Function> When a machining abnormality is detected by the abnormality detection means A, the home position return control means C operates in response and instructs the numerical control means B to execute a home position return program. . As a result, the numerical control means B executes the home position return program stored in the storage means A. This home position return program is programmed with a movement command to move the machining tool in a direction perpendicular to the axis of the machined hole and a home position return movement in a direction parallel to the axis of the machined hole, and when this program is executed, Therefore, even if the tool cannot be removed from the machined hole unless the tool is moved in a direction perpendicular to the axis of the machined hole, the return to the original position can be performed automatically.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, 10 is a bed of the machine body 1, on which a table 1) on which a workpiece W is placed is guided so as to be movable in a direction perpendicular to the paper (X-axis direction). A column 13 that movably guides the spindle head 12 in the vertical direction (Y-axis direction) is movably guided in the left-right direction (Y-axis direction).

The table 1) is moved in the X-axis direction by a servo motor 14 fixed on the bed 10, and the spindle head 12
is a servo motor 1 attached to the rear end of the bed 10.
5 and a servo motor 1 attached to the top of the column 13.
6 in the Y-axis direction and in the Y-axis direction.

These servo motors 14 to 16 are connected to the drive unit 5.
It is connected to the numerical control device 2 via the numerical control device 2, and is rotationally driven by the distribution pulse outputted from the numerical control device 2. Additionally, meter relays 22a to 22 are provided between the drive unit 5 and the servo motors 14 to 16 to detect when each axis servo motor 14 to 16 is overloaded.
c is provided.

Reference numeral 17 denotes a main shaft that is mounted vertically on the main shaft hood 12 and is rotationally driven by a main shaft motor 18, and tools T in the tool magazine are selectively mounted on the main shaft by a tool changing device of the circuit.

Also, the tool T
An abnormality detection circuit 19 is provided which determines whether the load torque acting on the motor is within a permissible value and outputs an abnormality detection signal when the load torque exceeds the permissible value.

2 is a known numerical control device, and the internal memory 2a of this numerical control device 2 contains, in addition to machining programs inputted by the tape league 30, etc., the data shown in FIGS. 4(a) and (b)
A pair of home position return programs shown in ○RPI, ○RP
2 is remembered. This original position return program ORP
1. Of ○RP2, the home position return program 0RPI is
A skip function code G31 is programmed in block N200 in order to return the Z-axis to its original position from the beginning and interrupt feeding if the tool T cannot be pulled out of the machined hole.

On the other hand, the home position return program 0RP2 successively performs X-axis home position return, Y-axis home position return, and Z-axis home position return. is the sequence control device 3
A skip function code G31 is programmed to interrupt the feed at that point when a skip signal is sent from the feeder.

In addition, the blocks N303 and 3 next to the blocks N302 and 304 in which the home position return command in the X and Y axis directions are programmed are
05 is programmed with return programs X-[A*#1) and Y-(A*#1] that return the direction opposite to the original position direction.A in this program represents a constant, and #1 is , indicates the parameter name whose value is incremented in Pro Nori N301.

A sequence control device 3 is connected to the numerical control device 2, and one of a plurality of programs is selected and executed according to a command from the sequence control device 3. That is, when the sequence control device 3 outputs a sequence number corresponding to the first block of a plurality of programs and a program search command is output, the numerical control device 2 searches for the given sequence number. After that, when a start command is given, the numerical control program after the searched block is executed.

When machining of the workpiece W is started, the sequence control device 3 monitors the output of the abnormality detection circuit 19, and if an overload occurs during machining and an abnormality detection signal is output from the abnormality detection circuit 19, the sequence control device 3 monitors the output of the abnormality detection circuit 19. A sequence program is created to carry out the home position return process shown in the flowchart of FIG.

That is, when the occurrence of an abnormality is detected, the sequence control device 3 supplies a reset7) signal to the numerical control device 2 to interrupt the running program (50), and
After that, send the first block number 200 of the home position return program 0RPI to the numerical control device 2^ to instruct a program search (51), and then give a start command to the numerical control device 2 to start the home position return program 0RPI. Let it run.

As a result, the numerical control device 2 executes the home position return program 0.
G31, F20. which are programmed at the beginning of RPI.
Zloo is executed and pulse distribution is performed to move the tool T in the Z-axis direction at the commanded speed.

After this sending is started, the sequence control device 3
Whether or not the servo motor 16 is loaded is checked depending on whether an overload signal is not sent from the meter relay 22C until the rad 12 returns to its original position on the main shaft (54), and an overload signal is sent. If the rad 12 returns to the home position on the main shaft without being stopped and a program completion signal is sent from the numerical control device 2, the home position return process is completed here, but the state shown in FIG. When return to the home position is started and an overload signal is sent from the meter relay 22C, at that point a skip signal is sent to the numerical control device 2 to interrupt the feeding, and #1000 is sent.
Set address output to 155), home position return program 0
Run RP2.

That is, the sequence control device 3 sends the sequence number 300 of the first block of the home position return program 0RP2 to the numerical control device 2, and
2 (56), and then instructs the execution of the home position return program ○RP2 (57).
While the output of address 000 is 1, blocks N301 to 3
Command WHILE (#1000) to repeat program 07
EQI)001 is programmed, and a command to increase the content of parameter #1 by 1 is programmed in block N301.

Block N302 includes G28 to return the tool T to the origin of the X axis. G31. XO is programmed, and when this program is read, the numerical control device 2 distributes pulses to the X-axis to move the tool T toward the origin of the X-axis. Thereby, the tool T moves in a direction perpendicular to the axis of the machined hole Wa, and when the tool T engages with a different part of the machined hole Wa, the movement is stopped. In this way, the tool T is the workpiece W
When the servo motor 14 engages with the machined hole Wa and stops, the servo motor 14
The drive current increases, and the meter relay 22a operates to output an overload signal OLX. Then, in response to the operation of the meter relay 22a, the sequence control device 3 sends a skip signal to the numerical control device 2 to interrupt the home position return movement currently being executed.

As a result, the return program X-(A*#1) stored in block N303 is executed. Since the initial value of parameter #1 is zero, the return movement amount in this case is zero, and the return operation is performed. will not be carried out. Further, following this, based on the program of blocks N304 and N305,
Return to the original position and return operation to the Y axis are performed. In this case as well, since parameter #1 is zero, no return operation is performed.

By such return movement in the X-axis direction and the Y-axis direction, the tool T can be pulled out of the machined hole Wa by moving it in the X-axis direction, as shown by the two-dot chain line in Fig. 6. Therefore, following this, block N306
Home position return commands in the X-axis direction 02B, 031. Z
When O is executed, the tool T leaves the machined hole Wa of the workpiece W and moves to the original position H in the X-axis direction. An i return is performed. When it is confirmed that the return to the original position in the X-axis direction is completed in this way, the sequence control device 3 sets the output #1000 to 0. As a result, the numerical control device 2 controls the block N3.
00 to block N308, and the execution of the original position return program 0RP2 is ended.

On the other hand, if it is not possible to return to the original position in the X-axis direction by just one movement in the XY directions described above, 1 is added to the content of parameter #1 in block N301, and then the XYZ movement from block N302 onward is The home position return command in each axial direction is executed again, and by repeating this operation, the tool T is removed from the machined hole Wa and returned to the home position.

When the process of returning to the original position is completed in this way, the workpiece W is automatically replaced and machining is continued.

<Effects of the Invention> As described above, in the present invention, when an abnormality occurs during machining, the machining tool is moved in a direction perpendicular to the axis of the machined hole, and then moved in a direction parallel to the axis of the machined hole. Since the return to home position operation in the direction is automatically performed, even if the tool cannot be removed from the workpiece only by moving in the axial direction, the return to home position can be performed automatically, making unattended operation more efficient. This has the advantage of being able to do more.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram for clearly demonstrating the present invention, Figures 2-
FIG. 4 shows an embodiment of the present invention, and FIG. 2 is a schematic side view of a machine tool along with a block diagram of a control circuit.
FIG. 3 is a flowchart showing the operation of the sequence control device 3 in FIG. 2, and FIGS.
A diagram showing the original position return programs ORP 1 and ORP2 stored in the memory 2a of the numerical control device 2 in the figure, FIG. 5 is a diagram showing the engagement relationship between the workpiece and the tool in the machining state,
FIG. 6 is an enlarged cross-sectional view taken along the line Vl-VI in FIG. 5. 1... Machine body, 2... Numerical control device, 2a...
Memory, 3... Sequence control device, 12... Spindle head, 17... Spindle, 18... Spindle motor, 19
... Abnormality detection circuit, 22a to 22C... Make relay, T... Tool, W... Workpiece.

Claims (1)

[Claims] (1) A machine tool equipped with a home position return function, which stores a home position return program that moves the machining tool in the radial direction within the machined hole and then moves it in the axial direction to return to the home position. a storage means, an abnormality detection means for detecting the occurrence of an abnormality during machining, and a home position for causing the numerical control means to execute the program for returning to the home position in response to the abnormality being detected by the abnormality detection means. A machine tool equipped with a home position return function, characterized in that it is equipped with a return control means.