JPS6119380B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a numerically controlled machine tool that processes a workpiece into a desired shape by controlling the relative positions of a tool and a workpiece based on a programmed numerical control program, after replacing a broken tool. Regarding the method for restarting machining of a workpiece, the purpose is to replace the broken tool when a tool breaks during machining and then return to the beginning of the machining process where the tool broke. To restart numerical control so that machining of a workpiece can be continued even if a tool breaks. In numerically controlled machine tools, tools may break during machining due to factors such as reduced sharpness of the tool, so tools are designed to detect tool breakage during machining and prevent machining from continuing with a broken tool. There is a need to. For this reason, in conventional numerically controlled machine tools, tool breakage is detected at appropriate intervals during machining, and if a tool breakage is detected, machining of the workpiece is interrupted and the broken tool is replaced. That's what I was doing. However, in general numerically controlled machine tools, the position of the tool at the time of tool breakage cannot be known after the broken tool is replaced, so even if the broken tool is replaced, the tool cannot be returned to its original position. I can't. Therefore, with conventional numerically controlled machine tools, even if a broken tool is replaced, it is not possible to continue machining the workpiece, and the workpiece that is being machined is
It was necessary to manually process the unprocessed parts or to start over from the beginning. If the shape of the workpiece is simple, you can manually machine the unmachined part or restart the machining cycle from the beginning.
However, when machining a workpiece with a three-dimensional curve, it is impossible to manually machine the unmachined part, and machining the workpiece takes several hours or more. Therefore, restarting the machining of the workpiece from the beginning causes a significant increase in the cycle time of workpiece machining, which is a big problem. The present invention has been made in view of such conventional problems, and the present invention is designed to position the tool at a predetermined fixed position when changing a tool or detecting a breakage, and to program the tool after changing the tool or detecting a breakage. Focusing on the fact that the machining program is always programmed with the fixed position as the movement start point, when a tool breakage is detected or when a tool is replaced, the next program that is programmed following the tool breakage detection command or the tool change command is The data related to the first block number of the machining program will be updated and stored, and if a tool breaks, after replacing the broken tool, the data will be traced back to the numerical control program of the block number that was stored when the breakage was detected. This feature is characterized in that the numerically controlled machining is restarted. Embodiments of the present invention will be described below based on the drawings. In FIGS. 1 and 2, 10 is a bed having a column 11 at the rear end.
A slide table 13 is installed above via the saddle 12.
A rotary table 14 on which a workpiece W is placed is provided on the slide table 13. The saddle 12 is guided so as to be movable in the left-right direction (Z-axis direction) in FIG. 2 with respect to the bed 10, and is moved by a servo motor 15 provided at the rear end of the bed 10. . Further, the slide table 13 is guided so as to be movable in the left-right direction (X-axis direction) in FIG. ing. On the other hand, a spindle head 18 that supports the spindle 17 is guided in the column 11 so that it can move in the vertical direction (Y-axis direction), and is moved by a servo motor 19 fixed to the top of the column 11. It's becoming like that. Further, a tool magazine 20 that stores a large number of tools T is placed on the top of the column 11, and one of the tools T stored in this tool magazine 20 is transferred to the main shaft 17 by the tool exchange arm 21.
It is now being installed on Note that a plurality of the same tools are stored in the tool magazine 20, and when the tool T is broken during machining, the same tool is searched for and replaced with the broken tool. Further, on the column 11 side of the slide table 13, a breakage detection head 22 for detecting breakage of the tool T during machining of the workpiece W is mounted. As shown in FIG. 3, this breakage detection head 22 is guided movably in the z-axis direction (horizontal direction in FIG. 3) by a head body 23 and inside this head body 23, and is guided so that it can move in the z-axis direction (horizontal direction in FIG. 3). A moving shaft 25 having a section 24 and a moving shaft 25 compressed between the moving shaft 25 and the head body 23 and moving the moving shaft 25 to z
When the moving shaft 25 moves, the head body 23 is connected to the atmosphere through an annular groove 25a formed in the moving shaft 25. A compressed air supply path 27 is bored. Compressed air supply path 27
The positional relationship between the annular groove 25a and the annular groove 25a is such that the normal tool T
When the compressed air supply path 27 is moved along the axis and positioned at the breakage detection position shown by the two-dot chain line in FIG.
is adapted to communicate with the annular groove 25a, and will not communicate if the tool T is broken and the tool length is shortened. Compressed air is supplied to this compressed air supply path 27 via a throttle valve 28, and if the tool T is not broken, the throttle is opened when the tool T is positioned at the breakage detection position. valve 2
After passing through 8, the air pressure decreases. The breakage detection circuit 29 is a circuit that detects a breakage of the tool T by detecting a drop in air pressure after passing through the throttle valve 28 based on a signal from the pressure switch PS, and receives a breakage detection command from the numerical control device 30 described later. When the signal TSK is applied, it is determined whether or not the tool T is broken, and if the tool T is broken, a breakage detection signal TSS is output. FIG. 4 shows a control circuit for controlling the operation of the machine body described above to process the workpiece W, including a numerical control device 30, a servo motor drive circuit 31, an index control circuit 32, and a tool conversion detection circuit 33. and a breakage detection circuit 29. The servo motor drive circuit 31 is connected to the numerical control device 3
The servo motors 15, 16, and 19 are driven in accordance with the distribution pulse outputted from 0, and is composed of a deviation counter, a DA converter, a drive amplifier, and the like. On the other hand, the index control circuit 32 is for indexing the tool socket S in which the tool T specified by the T code of the numerical control program is housed to the tool exchange position. When the indexing is completed, the magazine drive device 34 is energized to index the specified tool socket S to the tool exchange position, and when the indexing is completed, the indexing is completed WFS.
is output to the numerical control device 30. The tool exchange control circuit 33 also includes a circuit for exchanging the tool T indexed to the tool exchange position and a tool on the spindle 17, and an arm drive device 35 to which a tool exchange command TCC is given from the numerical control device 30. The tool T is energized and replaced, and when the tool replacement is completed, a tool replacement completion signal TCF is sent to the numerical control device 30.
is now output. The numerical control device 30 distributes pulses based on a numerical control program programmed in advance and sends commands such as tool exchange to the outside to control the workpiece W.
It is designed to perform a series of processes fully automatically, and is constructed using a small computer such as a minicomputer. In this embodiment, it is detected whether the tool T is broken during machining of the workpiece W, and if breakage of the tool T is detected, the broken tool is replaced with a spare tool and machining is restarted. It also has functions. In other words, as shown in Fig. 5, if tool breakage is detected every time the machining of multiple machining points is completed, the tool T will break during the process. However, since the breakage of tool T is not detected until the end of the process, it is not possible to know where the machine was being machined when tool T broke, but the tool breakage occurred at least before. Since this is after the time when the breakage was detected, if the machining is resumed by going back to the previous breakage detection point as shown by the two-dot chain line in Fig. 5,
Machining of the workpiece W can be continued without almost increasing the machining time. For this reason, in the numerical control device 30 of this embodiment, when no tool breakage is detected, the block number in which the breakage detection command was programmed is stored, and when the tool T is broken, the block number is stored. The numerically controlled machining is restarted by going back to the block next to the stored block so that the machining is restarted from the beginning of the machining process in which the tool broke. FIG. 6 shows an example of a numerical control program for detecting tool breakage during machining, in which M codes M48 for detecting breakage are inserted at predetermined intervals in the machining program. In addition, when detecting breakage, the tool T must be positioned at the breakage detection position described above, so the numerical control data for moving the tool T from the machining position to the breakage detection position is required before the breakage detection program. After the breakage detection program, numerical control data for moving the tool T from the breakage detection position to the next machining position is programmed. When numerically controlled machining is performed based on such a numerical control program, for example, after the second machining with tool T01 is completed, the tool is stopped by executing breakage detection command M48 programmed in block N046. If a breakage is detected, after replacing the broken tool, machining is resumed going back to the block N024 following the block in which the previous breakage detection command is programmed. In addition, if tool T is detected to be broken after a machining process that requires a tool change in the middle, such as the third machining, it means that the tool was broken in the middle of machining with the replaced tool T02. In such a case, after replacing the broken tool, numerically controlled machining is restarted by tracing back to the first block N064 of the machining program after the tool exchange to tool T02. FIGS. 7a and 7b show numerical control programs for replacing a broken tool with a spare tool, and these programs are executed when a breakage of the tool T is detected. The process when the tool T breaks differs depending on whether the tool was replaced during the machining process before the breakage was detected. The numerical control program for breakage processing A shown in Fig. 7a is for the case where the tool is not replaced during the machining process, and after replacing the broken tool with a spare tool, the tool is returned to the breakage detection position. ing. On the other hand, the numerical control program for breakage treatment B shown in Figure 7b is for a case where a tool is changed in the middle of the machining process, and the machining after the tool change is programmed with the origin as the movement start position. The spare tool that has been replaced in response to the current situation is positioned at its original position. Note that the tool numbers 〓〓〓 and ## in the program indicate the numbers of the spare tool and the next process tool, respectively, and the tool is replaced by applying the tool number stamped before replacing the broken tool. The numerical control program for replacing these broken tools is read by the tape reader TR and stored in the NC data area in the storage device 36, together with the aforementioned machining program, as shown in FIG. . The numerical control data for machining stored in this NC data area is sequentially read out by the numerical control device 30 to perform machining of the workpiece W, and when a breakage of the tool is detected, a breakage processing The numerical control program is read out and the broken tool is replaced. Further, inside the storage device 36, as shown in FIG. 8, a data area for tool exchange formed by a tool table and a magazine table for exchanging tools, and a data area for handling breakage are also provided. These data areas are accessed as needed. As shown in Table 1, the tool enable stores data indicating whether the tool can be used and the number of a spare tool in relation to the tool number. A zero is written in the column indicating whether or not the tool can be used. On the other hand, the magazine table stores which tool is attached to which tool socket, and is rewritten every time a tool is replaced.

[Table] In addition, the data area for breakage processing includes the current tool register TNR that stores the number of the currently used tool, the next process tool register NTR that stores the number of the tool that will be used in the next process, and the current Current block register NOR stores the block number of the numerical control program being executed, return block register NAR stores the block number to return to when a tool breaks, and whether workpiece W is being machined or a broken tool is being replaced. There is a mode register MOR etc. that stores whether the Next, specific operations of the numerical control device 30 during workpiece machining, particularly when detecting tool breakage, will be explained based on the flowcharts shown in FIGS. 9 to 12. Now, when a start switch (not shown) is pressed with the numerical control program shown in FIG. 6 written in the storage device 36, the numerical control device 30 starts the main routine program shown in FIG. to be executed. First, in step 10, the current block register NOR and the breakage detection block register NAR are reset to zero, and then in step 11, the mode register is reset to zero.
Set MOR to 5, which indicates the workpiece machining mode, and proceed to step 12. At step 12, 1 is added to the contents of the current block register NOR, and the current block register is
The content of NOR becomes 1. Step 13 is a step for sequentially reading out the numerical control data of the block currently specified by the block register NOR.
Since the stored value of NOR is 1, the data of the T code programmed first in N001 is read out. In step 14, it is determined whether the read data represents the end of the block. If the data represents the end of the block, the process returns to step 12 and the current block register is stored.
At the step of adding 1 to the stored value of NOR, if the data does not represent the end of the block, the process moves to step 15. Steps 15 to 18 are for decoding the read code and moving the operation to a processing routine according to the decoded code, and if the read code is one of X, Y, or Z. In this case, the pulse distribution routine PGEN shown in FIG.
If it is a G code, it jumps to the routine of steps 20 to 25, and if it is an M code, it jumps to the M code routine shown in FIG.
Jumps to MCR, and if it is a T code, jumps to tool selection routine TSR shown in FIG. In this case, since the read code is a T code, jump to the tool indexing routine TSR,
Processing for tool indexing is performed. That is, in step 80, the programmed tool number is read following the T code, and in step 81, the tool table is referenced to determine whether the designated tool can be used. If the specified tool can be used, the process directly proceeds to step 85; if the specified tool cannot be used, a spare tool is searched for in step 82, and the process proceeds to step 85. Incidentally, if there is no spare tool available, this is determined in step 83, and in step 84, a display indicating that there is no tool is made and the operation of the numerical control device 30 is stopped. Step 85 is a step for storing the specified tool number in the next process tool register NTR. In this case, since 01 is programmed as the tool number, 01 is written in the next process tool register NTR. Further, the following step 86 is a step of searching the magazine table for the number of the tool socket S containing the specified tool.
When the socket number containing the designated tool is searched, the process moves to step 87 and the searched socket number is output to the index control circuit 32.
As a result, the tool specified by the program or the spare tool of the specified tool is indexed to the tool conversion position. When it is determined in step 88 that the indexing of the tool has been completed, the process returns to step 13 of the main routine to read out the next numerical control data. Since only T01 is programmed in the block N001, data indicating the end of the block is programmed next to T01, and this is read out in step 13. When the data indicating the end of the block is read, this is determined in step 14 and the process returns to step 12, where the current block register is read.
1 is added to the stored value of NOR, and the numerical data is read out again in step 13. This results in
The M code data programmed at the beginning of block N002 is read out. If the read data is M code,
From step 17, the program jumps to the M code routine MCR, where M function processing is performed. First, in step 50, the numerical data programmed following the M code is read, and from step 51 to step 5.
In step 3, it is determined what the command is.
In this embodiment, M02 commands to stop operation, M06 commands tool exchange, and M48 commands tool breakage detection.
When the read numerical data is 02, 06, or 48, the process jumps to steps 75, 56, and 61, respectively, and performs the commanded operation. What is programmed into the N002 block is
Since it is M06, the process moves to step 56. Step 56 determines whether the operation mode is the machining mode based on whether the content of the mode register MOR is 5 or not, and then proceeds to step 59 via steps 57 and 58 or directly proceeds to step 59. However, in this case, since the content of the mode register MOR is 5, the process goes to step 5 via steps 57 and 58.
Move to 9. Step 57 is a step in which the block number returned after the replacement of the broken tool is completed is updated and memorized every time the tool is replaced.
The stored value of NOR, 002, is returned to the block register.
Transferred to NAR. In addition, step 58 is a step for writing the block number data in the return block register NAR at a step for storing that the machining program that is programmed after the block to return to when the tool breaks is set to the tool exchange position as the movement start point. 1 is written to the first bit that does not exist. Step 59 is a step for instructing a tool change, and a tool change command TCC is sent to the tool change control circuit 33.
Output. As a result, the arm drive device 35 is energized, the tool exchange arm 21 performs tool exchange, and the tool T with tool number 01 is mounted on the spindle 17. When the installation of the tool T is completed in this way, the number 01 of the installed tool T is stored in the current tool register TNR in step 60, and then the process moves to step 13 of the main routine to read the next numerical control data. will be held. N002 block has M06
Since T02 is programmed next to T02, tool T with tool number 02 is indexed to the tool change position in the same manner as described above, and is stored in the next process tool register NTR.
02 is stored. The program after block N003 is a machining program that performs the first machining with the tool change position as the starting point.When G00 X2000 Y70000 Z25000 programmed in block N003 are read out in order, Movement begins. That is, the initially programmed G
When the code G00 is read out, the process moves from step 16 to step 20, and in step 21, the pulse distribution speed is set to the fast forward speed, and following the G code, the programmed movement amount program is read out. When the X, Y, and Z codes are read, the program jumps to the pulse distribution routine PGEN shown in FIG. 10 and pulse distribution is performed. First, the moving direction is determined in steps 30a to 30b, and the moving direction is registered in the moving direction register in steps 31a to 31c.
Flags corresponding to the X, Y, and Z axes of the MDR are set, and in step 32, the numerical data of the amount of movement is read. Then, in step 33, the movement amount data is preset in the movement amount counter MVC, and then the process proceeds to step 34, where it is stored whether the movement direction is positive or negative, and the process proceeds to step 35. At step 35, one pulse is distributed in the specified direction, and at step 36, the movement amount counter is
Subtract 1 from the MVC preset value. Block 003
Since X2000 is programmed first,
First, the workpiece W is moved in the positive direction along the X-axis, and the tool T is positioned in the X-axis direction. Then, when the positioning of the tool T is completed and the count value of the movement amount counter MVC becomes zero, this is determined in step 37, and step 1 of the main routine is started.
Returning to step 3, the same operation is performed for the Y-axis and Z-axis movement commands, and the tool T is positioned to the first processing location. Block N004 has a program that distributes 1200 pulses in the Z-axis direction by cutting the tool.
When the G01 Z1200 is programmed and this program is read, the feed rate is preset to the cutting speed in step 23 of the main routine, then jumps to the pulse distribution routine PGEN and the Z1200 is programmed.
1200 pulses are distributed to the axis. As a result, the first machining location of the workpiece W is machined. Thereafter, machining is similarly performed at an appropriate number of machining locations as the first machining based on the numerical control program for machining from block N005 onwards. When the first machining consisting of machining a plurality of machining locations is completed in this manner, breakage of the tool T01 is detected. That is, blocks N021, 022,
When the movement command program 023 is read out, the tool T01 is positioned from the machining position to the breakage detection position, the tip of the tool T01 is engaged with the tool contact part 24 of the breakage detection head 22, and then the block
When the data of M48 programmed in N023 is read out, breakage detection processing is performed. When the numerical controller data of M48 is read, M
The code routine MCR moves from step 53 to step 61 to read the signal sent from the breakage detection circuit 29. Step 62 is the breakage detection circuit 2.
In this step, it is determined whether or not the tool T is broken based on the signal sent from the tool T.
If it is determined that the
If it is determined that the tool T is not broken, the process moves to step 63. Assuming that the tool T01 did not break during the first machining, the process moves from step 62 to step 63. Step 63 is a step in which the return block number is updated and stored every time a breakage is detected after the replacement of the broken tool is completed, and the value currently stored in the block register NOR is transferred to the return block register NAR in the same manner as in step 57 described above. do. In this case, since the stored value of NOR is 023, the stored value of return block register NAR is updated from 002 to 023. In this way, the return block register
The return block number data stored in the NAR is rewritten both when the tool T is replaced and when breakage of the tool T is not detected. Become. Further, step 64 is a step in which it is stored that the machining program programmed after the block returned after replacing the broken tool is programmed with the breakage detection position as the movement start point, and the 1st bit of the return block register NAR is set to 0. is written. When the breakage detection process commanded by M48 is completed in this way, the main routine returns again.
The program of the next block N024 is read out.
Tools for programs from blocks N024 to N045
The second machining by T01 is performed, and the tool T01 is moved from the breakage detection position to the machining position based on the data of several blocks after N024, and after that, machining of a plurality of machining locations is performed by T01. and,
When the machining is completed, the tool T01 is again positioned at the breakage detection position, and M48 of block N046 issues a command to detect the tool breakage. Assuming that the tool T01 breaks during the second machining, this is determined in step 62 of the M code routine MCR, and the breakage processing program from step 65 onwards is executed. First, in step 65, 3 is written to the mode register MOR to remember that the breakage processing mode has been entered, and then the process moves to step 66 where tool T01 in the tool table is set.
Write 0 in the usability column to remember that tool T01 is broken. And after this, step 67
Depending on whether the first bit of the return block register NAR is 0 or not, the machining program programmed after the return block is programmed with the breakage detection position as the movement start point, or the tool change position is moved. It is determined whether the breakage detection position is programmed as the start point, and if it is determined that the breakage detection position is programmed as the start point of movement, the process moves to step 68 to confirm that the tool exchange position is programmed as the start point of movement. If it is determined, the process moves to step 69. Steps 68 and 69 are steps for presetting the first block number of the breakage processing program for replacing a broken tool with a spare tool in the current block register NOR.In step 68, 980, which is the first block number of the breakage processing A, is preset in the current block register NOR.
In step 69, 990, which is the leading block number of breakage processing B, is preset in the current block register NOR. In this case, since the first bit of the return block register NAR is 0, 980 is preset to the current block register NOR in step 68. Step 70 is a step in which a spare tool for the broken tool is searched by referring to the tool table.
Spare tool T01 is searched. If there is no spare tool available, this is determined in step 71, and the operation is stopped in step 72 with an indication that there is no spare tool, but in this case, as shown in Table 1, T06 as a spare tool for T01 can be used, the process moves to step 73. Steps 73 and 7
4 is the tool number of the breakage processing program〓〓,
In this step, the tool numbers of the spare tool and the next process tool are substituted in the ## column, and in this case, 06 and 02 are substituted. When the process of step 74 is completed, the main routine is returned and the numerical control data is read, but since the value currently stored in the block register NOR is 980, the numerical value of breakage processing A with 980 as the first block number is Control program data is read. The breakage processing program A is a program that returns the tool T to the breakage detection position after replacing the broken tool.
Return the spindle 17 with tool T01 attached to the tool exchange position using G28YO, index the spare tool T06 to the tool exchange position using T of block N982, and
Replace tool T01 with spare tool T06 in M06 of N983. Then, the tool T02 for the next process is indexed to the tool exchange position again by T## of block N983. When the replacement of the tool T01 is completed in this manner, the spare tool T06 mounted on the spindle 17 is positioned again at the breakage detection position according to the programs of blocks 984 and 985. M02 programmed in block N986 indicates the end of the breakage processing program, and when this M02 program is read out, step 5 of the M code routine MCR is executed.
The process moves from step 1 to step 75, and the process of M02 is performed. Step 75 is the mode register MOR.
This is a step to determine whether the numerical control program that has been executed up to now is for handling breakage or addition, depending on whether the memorized value of is 3. If it is determined that there is one, the process moves to step 76, and if it is determined that it is for processing, the operation is stopped.
In this case, the value stored in the mode register MOR is 3.
Therefore, the process moves to step 76. Steps 76 and 77 are return block registers.
This is a step to return to the machining program following the block number stored in the NAR and resume operation.In step 76, the return block register is
After presetting block number 023 stored in NAR into the current block register NOR, 5 is written into the mode register MOR in step 77.
When these operations are completed, the process returns to step 12 of the main routine. When returning to step 12 of the main routine, 1 is added to the value currently stored in the block register NOR, so the numerical control program programmed after the block number next to the block number stored in the return block register NAR is executed. be done. In this case, since 023 is stored as the return block number in the return block register MAR, the program for performing the second machining programmed after block N024 is executed again. This allows the spare tool for tool T01 to be
Processing after the second time is continued by T06. On the other hand, if tool breakage is detected after a machining process in which the tool is used in the middle of the machining process, such as the third machining, in other words, if the tool is When a breakage of the tool T is detected in the breakage detection according to the commands of the program, the following breakage processing is performed. In other words, if a tool is replaced during the machining process, 1 is written to the first bit of the return block register NAR when tool T is replaced, so if tool T is detected as broken, the tool is broken. Steps 66 to 6 of the processing routine
8, and 990 is currently preset in the block register NOR. Therefore, when a tool is replaced during the machining process, the broken tool is replaced with a spare tool according to the numerical control program for breakage treatment B shown in FIG. 7b. In this breakage processing B program, after replacing the broken tool with a spare tool, the tool is not positioned at the breakage detection position, and after the tool is replaced, the main spindle 17 on which the spare tool is mounted is rotated in each axial direction. Since the main shaft 17 is programmed to be located at the original position, the breakage process is completed with the main shaft 17 located at the original position in each axis direction. When the breakage process is completed and M02 programmed in the block of N994 is read out, the process moves to steps 75 and 76 of the M code routine MCR, and the value stored in the return block register NAR is transferred to the current block register NOR. After that, the main routine returns to the main routine, but if a tool is changed during the process, the block number in which the tool was changed is stored in the return block register NAR, so the tool is not replaced when the main routine is returned. The programmed machining program will be executed from the block next to the block that was entered. Therefore, even if tools are replaced during the machining process, machining of the workpiece can be continued after replacing the broken tool. In addition, in the above embodiment, each operation of positioning a broken tool to a tool exchange position, searching for a spare tool, replacing it with a spare tool, and positioning a spare tool to a breakage detection position can be performed automatically and continuously. However, the present invention can also be applied to numerically controlled machine tools in which some or all of these operations are performed manually. Furthermore, in the above embodiment, the first block number is updated and memorized both when replacing the tool and when detecting breakage. If you return to the point of replacement and restart machining, you may be able to update and store the first block number only when the tool is replaced.If you do not change the tool in the middle of the machining process, the first block number will be updated only when a breakage is detected. The block number may be updated and stored. As described above, in the present invention, data related to the first block number of the machining process that is programmed following tool exchange or tool breakage detection is updated and stored every time tool change or tool breakage is detected. If a tool breaks, the broken tool is replaced and then numerical control is resumed by going back to the numerical control program of the block number that was stored when the breakage was detected. Even if a tool breaks during machining of a workpiece, automatic machining using numerical control can be continued by replacing the broken tool. Therefore, even if a tool breaks while machining a workpiece, the workpiece can be machined again from the beginning as in the conventional method.
This has the advantage that there is no need to manually process the remaining unprocessed portion.

[Brief explanation of the drawing]

1 and 2 show the schematic structure of the machine body constituting the numerically controlled machine tool according to the present invention. FIG. 1 is a front view of the machine body, FIG. 2 is a side view of the machine body, and FIG. The figure is a cross-sectional view showing the structure of the breakage detection head 22 in FIGS. 1 and 2, FIG. 4 is a block diagram showing an example of the control circuit of the numerically controlled machine tool according to the present invention, and FIG. 6 is a diagram showing a program sheet showing an example of a numerical control program for detecting tool breakage during machining of a workpiece.
Figures 7a and b are diagrams showing the numerical control program for replacing a broken tool with a spare tool, and Figure 8 is a diagram showing the numerical control program for replacing a broken tool with a spare tool.
9 to 12 are flowcharts for explaining the operation of the numerical control device 30 in FIG. 3. FIG. 9 is a main routine, and FIG. Pulse distribution routine PGEN, Figure 11 shows M code routine MCR, Figure 12 shows tool selection routine TSR.
FIG. 10...Bed, 11...Column, 13...Slide table, 15, 16, 19...Servo motor, 17...Spindle, 18...Spindle head, 20...
Magazine, 21... Tool exchange arm, 22... Breakage detection head, 29... Breakage detection circuit, 30...
... Numerical control device, 31 ... Servo motor drive circuit, 32 ... Index control circuit, 33 ... Tool exchange control circuit, 34 ... Magazine drive device, 35 ... Arm drive device, 36 ... Storage device, 57 ...The step of updating and memorizing the block number when replacing the tool,
63... Step of updating and storing the block number when no tool breakage is detected, 76, 77...
...Step for returning to the stored block and restarting numerically controlled machining after replacing a broken tool, T...Tool, W...Workpiece.

Claims (1)

[Claims] 1 A method for restarting machining of a workpiece after replacing a broken tool in a numerically controlled machine tool that detects tool breakage by positioning the tool at a breakage detection position at appropriate intervals during machining of the workpiece. A method for sequentially updating and storing data related to the first block number of a machining program programmed following a tool breakage command or a tool change command program when a tool breakage is detected or when a tool is replaced. and when a broken tool is detected, the broken tool is replaced with a new tool, and then numerical control machining is restarted by going back to the numerical control program of the updated and stored first block number. A method for restarting machining in numerically controlled machine tools.