JPH0220379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a numerical control device that controls the operation of a machine tool by distributing pulses to a plurality of control axes according to numerical control data input in advance. The purpose of this is to distribute pulses to the main control axis that controls the movement of processing tools, etc. according to the main numerical control program, and at the same time to distribute pulses from the time when the main numerical control program has been executed to a predetermined position. Processes such as pulse distribution to the sub-control axis can be executed independently and simultaneously with pulse distribution to the main control axis, and other operations unrelated to the movement of the machining tool can be performed from a position in the middle of the machining tool movement process. The goal is to help you get started.

In recent years, numerically controlled grinding machines not only move the grinding wheel forward and backward relative to the workpiece, but also move the grinding wheel correction tool forward and backward relative to the grinding wheel, index the workpiece table, feed the rest device, etc. Numerical control has come to be used to control the grinding wheel, but conventional numerical control devices cannot move the grinding wheel forward and backward in parallel, and other operations cannot be performed in parallel.
This was one of the reasons why it was not possible to shorten the machining cycle time.

In other words, if we consider moving the correction tool for grinding wheel correction as an example, although this movement cannot be performed during machining, the feed starts immediately after the grinding wheel starts moving backward, and the grinding wheel moves during the backward movement of the grinding wheel. It is possible to correct the wheel, and in this way, by the time the grinding wheel returns to the backward end, the grinding wheel correction has been completed and subsequent machining can be started immediately, reducing the machining cycle time. Can be shortened. However, in conventional numerical control devices, although it is possible to simultaneously distribute pulses to multiple axes such that the start time and completion time of movement are the same as in linear interpolation, Since it is impossible to perform pulse distribution at the same time at all, as described above, in parallel with the pulse distribution for retracting the grinding wheel, pulse distribution for moving the grinding wheel correction tool forward and backward for grinding wheel correction is performed to complete the machining cycle. I couldn't shorten the time.

The present invention has been developed in view of these conventional problems, and includes storing in a storage means a plurality of numerical control data programmed corresponding to each of a plurality of control axes that need to be operated independently. In addition, a pulse generation circuit capable of distributing pulses independently is provided for each axis, and when a start command is given, one numerical control data among the plurality of numerical control data stored in the storage means is provided. In response to this one numerical control data being executed up to a predetermined step, pulse distribution based on this one numerical control data and pulse distribution based on other numerical control data is performed simultaneously. This feature is characterized by the fact that they are performed in parallel.

Embodiments of the present invention will be described below based on the drawings. In FIG. 1, 10 is the workpiece W of the grinding wheel G.
In addition to numerically controlled machining of the workpiece W by controlling the forward and backward movements of the grinding wheel G, a grinding wheel correction tool is attached to the grinding wheel G.
This is a numerical control device that controls the forward and backward movement of the DT and corrects the grinding wheel G by numerical control, and includes an arithmetic processing device 11, a memory 12, and pulse generation circuits 13a, 13.
It is mainly composed of b. A program writing device 15 and a sequence control circuit 16 are connected to the arithmetic processing device 11 via an unillustrated interface.

The program writing device 15 writes a numerical control program for machining the workpiece shown in FIG. 2a and a numerical control program for grinding wheel correction shown in FIG. 2b before machining the workpiece. The loaded numerical control program is stored in a main program area MPA and a subprogram area SPA in the memory 12, respectively. The numerical control program for machining the workpiece moves the grinding wheel G rapidly forward by a distance D0, then moves it forward by a distance D1 at a rough grinding feed rate F1 and by a distance D2 at a fine grinding feed rate F2 to process the workpiece W. After that, the grinding wheel G is returned to the backward end by fast forwarding backward by a distance D3, and the block N003 before the block N004 in which the numerical control data for commanding the backward movement of the grinding wheel G is programmed. , an auxiliary function code M03 that instructs the start of grindstone correction is programmed.

In addition, since the grinding wheel correction tool DT is a rotary type, the program for grinding wheel correction is
After moving the DT forward by a distance D5 in rapid traverse, the grinding wheel correction is completed by moving the DT forward by a distance D6 at a speed F3, and after this, after returning the correction tool DT by a distance D5, the grinding wheel G is moved forward by a distance D6. This is to compensate for the decrease in the diameter of the grinding wheel G due to the grinding wheel correction.

On the other hand, the pulse generation circuits 13a and 13b send pulses to the drive units DUX and DUU, which drive the servo motor 17 for advancing and retracting the grinding wheel G and the servo motor 18 for advancing and retracting the correction tool DT, respectively, according to commands from the arithmetic processing unit 11. The pulse generation circuits 13a and 13b each include speed registers 20a and 20 for setting the pulse period.
b, oscillators 21a and 21 that generate pulses at the speed set in the speed registers 20a and 20b;
b, the output from these oscillators 21a and 21b is positive,
Gate circuits 23a, 2 that distribute as negative pulses
3b, and preset counters 22a and 22b which calculate the pulses output from the oscillators 21a and 21b and output pulse distribution completion signals DENX and DENU when the counted value becomes equal to the preset value. Then, the arithmetic processing unit 11
Each time the pulse distribution completion signals DENX and DENU are output from the preset counters 22a and 22b in the pulse generation circuits 13a and 13b, a new movement amount is calculated from the preset counter to which the pulse distribution completion signals DENX and DENU were sent. 22a or 22
By setting it to b, continuous pulse distribution is performed.

Furthermore, the sequence control circuit 16 has a circuit configuration shown in FIG.
When pressed, relay CR for machining cycle command is activated.
10 is turned on, instructing the numerical control device 10 to start executing the machining program shown in FIG. 2a, which is the main program. In addition, when the auxiliary function code MO3 is read out during the execution of this program, the code M03 is output from the numerical control device 10 to the sequence control circuit 16, and when the contact m03 is closed in response, the grinding wheel is corrected. The cycle command relay CR20 is turned on and commands the numerical control device 10 to start executing the subprogram, the grindstone correction program shown in FIG. 2b.

Auxiliary function code M0 that commands the start of grinding wheel correction
3 is programmed before the command to retreat the grinding wheel G, as described above, so that the retreating operation of the grinding wheel G and the grinding wheel correction operation are performed in parallel, as shown in FIG.

Next, the operation of the numerical control device 10, particularly the process of simultaneously performing the retracting operation of the grinding wheel G and the correcting operation of the grinding wheel G will be explained.

Arithmetic processing device 11 in the numerical control device 10
When operation is started, the program shown in FIGS. 5a and 5b is executed at regular intervals in response to an interrupt signal from the real-time lock generation circuit 25. Of this program, the programs in steps (31) to (43) are stored in the main program area of memory 12.
It executes the numerical control program for machining stored in the MPA, and the programs in steps (51) to (63) are stored in the subprogram area of memory 12.
It executes the grinding wheel correction program stored in the SPA, and in step (30), when it is determined that the grinding wheel correction command is being sent by relay CR10 of the sequence control circuit 16 being on. Execute the program in steps (31) to (43). Furthermore, if the relay CR20 of the sequence control circuit 16 is turned on, when the processing for executing the machining program is completed in steps (31) to (43), step (30) or By moving from step (33) to step (51) via step (50) and executing the program from step (51) to step (63), the grindstone repair program in subprogram area SPA is executed. Perform processing to execute.

The processing contents of the programs in steps (31) to (43) and the programs in steps (51) to (63) are almost the same, and in the programs in steps (31) to (43), Numerical control data is read from the main program area MPA and executed, whereas in the programs in steps (51) to (63), the numerical control data of the block specified by the subprogram counter SPC is read from the subprogram area SPA and executed. The only difference is in what they do. Note that the main program counter MPC and sub-program counter SPC are formed in predetermined areas within the memory 12.

Now, start switch of sequence control circuit 16
When START is pressed, relay CR10 turns on,
When the numerical control device 10 is instructed to execute the machining program, the arithmetic processing device 11 of the numerical control device 10 detects this in step (30),
Main program counter at step (32)
Executes initialization processing to reset the MPC to zero. After this, the process moves to step (35) via step (33), and the numerical control data G00XD0 of block N000 specified by the main program counter MPC is read out. It is determined whether or not the X-axis is currently distributing pulses by referring to the interlock table IRT described later. If it is not distributing, the program after step (37) performs processing according to the numerical control data. Let's do it.

In this case, since the numerical control data includes the G code, the step moves from step (37) to step (37a) to perform processing according to the G code, and then steps (38) and (40) ) to step (41), where pulse distribution processing is performed. In this pulse distribution process, in step (41), the data of the movement amount D1 is set in the movement amount counter XPTOTL formed in a buffer zone (not shown), and then in step (42), interlock table
Information indicating that X-axis pulse distribution has started is written to the IRT, and the main program counter MPC is incremented at step (43).
The process moves to step (70) of the pulse distribution routine PGR shown in FIG. 6, and the pulse distribution routine is executed once. Note that pulse distribution for the X-axis is started by executing the pulse distribution routine once, but subsequent pulse distribution processing is performed only by the pulse distribution routine.

That is, when the process starts from step (70) of the pulse distribution routine, first, in step (70), one of the pulse distribution completion flags DEFX and DEFU provided on each of the X and U axes is set.
X-axis pulse distribution completion flag corresponding to the moving axis
After resetting DEFX, data representing the moving direction is output to the X-axis pulse generation circuit 13a to switch the gate. Then, it is determined whether the pulse distribution to the X-axis is completed based on whether the count value of the X-axis movement amount counter XPTOTL is zero or not. If the pulse distribution is not completed, step ( 73) to (77), outputs the speed data and data representing the number of pulse distribution for one time to the pulse generation circuit 13a, outputs a pulse distribution start command, and then moves the number of pulse distribution. The amount counter XPTOTL is decremented and the process proceeds to the base routine.

As a result, the pulse generation circuit 13a distributes the set number of pulses to the X axis at the specified speed,
When this is completed, a distribution completion signal DENX is sent to the arithmetic processing unit 11. As a result, the arithmetic processing unit 11 starts execution from step (72) of the pulse distribution routine shown in FIG. After determining this, the process moves to step (73) and performs the same processing as in the previous case. When this process is completed, the process returns to the base routine. Thereafter, by repeating the same operation, the pulse distribution to the X-axis is continued, and the grinding wheel G is rapidly advanced.

Note that even during the pulse distribution operation according to this pulse distribution routine, the program shown in FIG. Not there,
Furthermore, since the relay CR20 remains in the OFF state and no grinding wheel correction command is given to the numerical control device 10, the process returns to the base routine from step (33) via step (50), and the actual processing is carried out. do nothing.

The number of pulses corresponding to the movement amount D1 commanded by the above operation is distributed and the movement amount counter is
When the contents of XPTOTL become zero, that is, when the rapid advance of the grinding wheel G is completed, step (75) is executed.
At step (76), the data indicating that the X-axis pulse distribution is in progress is erased from the interlock table IRT, and the X-axis pulse distribution completion flag is set at step (76), so that the routine shown in FIG. Then, in step (33), it is determined that the X-axis pulse distribution is completed.

Then, the process moves from step (33) to (35), and the processing of steps (33) to (43) is performed again.
Numerical control data G01 Then, when the programmed G0
The data of M03 programmed in 03 is read out, and in step (38a) this M03 data is
The code is sent to the sequence control circuit 16. Then, after returning to the base routine, when the process shown in FIG. Then, pulse distribution for retracting the grinding wheel G is started. As mentioned above, since the program shown in FIG.
The process starts from the moment the signal from the circuit 25 is sent out, and is completed by the time the next signal is sent out.

On the other hand, the M03 code is sequence control circuit 1
6, relay CR20 is energized and a subprogram execution command is sent to numerical control device 10. Then, as shown in FIG. 7, when the processing unit 11 executes the program shown in FIG. 5a in response to the signal sent from the RTC circuit 25 immediately after the X-axis pulse distribution is performed, , the program moves from step (33) to step (50), detects this in step (50), and performs the subprogram execution process starting from step (51) shown in FIG. 5B. As a result, first, the numerical control data G00 UD5 for the correction tool rapid traverse advance programmed in the first block N100 of the subprogram is
The program is read out, and then, in preset (56), it is determined whether or not pulse distribution is currently being performed for the U-axis by referring to the interlock table IRT, and the pulse distribution for the U-axis is determined. If not, the process moves to step (57) and subsequent steps to perform pulse distribution processing. In this case, U
Since there is no pulse distribution to the axis,
After moving from step (56) to step (57) and performing G code processing in step (57a),
In step (61), the U-axis movement amount D5 is set in the U-axis movement amount counter UPTOTL, and in step (62), the data during U-axis movement is written to the interlock table IRT, and at the same time, in step (63) Then, the subprogram counter PSC is incremented and the process moves to the pulse distribution routine.

As a result, after the pulse distribution speed and the initial distribution pulse number for grinding wheel retraction are set in the pulse generation circuit 13a and pulse distribution for the The pulse distribution speed and the initial number of distributed pulses are set, and pulse distribution to the U axis is started. As a result, the backward movement of the grinding wheel G and the rapid forward movement of the grinding wheel correction tool DT are started simultaneously.

Then, when the number of pulses set in the pulse distribution circuits 13a and 13b are distributed to the X-axis and the U-axis, respectively, distribution completion signals DENX and DENU are sent from the pulse generation circuits 13a and 13b, and in response, the The pulse distribution routine is executed again. Since the feed speeds of the two axes are usually different, the time required for the pulse generation circuits 13a and 13b to complete pulse distribution is different, and therefore the pulse distribution completion signals DENX and DENU are usually sent out at different times. The pulse distribution routine alternately performs pulse distribution processing for the X-axis and pulse distribution processing for the U-axis in a time-division manner. Although omitted in the flowchart, the pulse generation circuits 13a, 1
When the pulse distribution completion signals are sent from both of 3b at the same time, the pulse distribution process for the X axis is performed first, and then the pulse distribution process for the U axis is performed.

By repeating such processing, the backward movement of the grinding wheel G is controlled, and the subprograms for grinding wheel correction are read in order, and in response to this, the grinding wheel correction tool DT is fast-forwarded for grinding wheel correction. Pulse distribution for forward movement, forward cutting forward, and rapid backward movement is performed, and when this is completed, the grinding wheel position correction program G00XD6 programmed in subprogram block N103 is read out, and pulses for the Distribution takes place. However, as shown in Fig. 4, if the retraction of the grinding wheel G is not completed at this point and the pulse distribution to the X-axis continues, the interlock table IRT shows that the Since data indicating something has been written, this is determined at step (56) of the subprogram execution routine, and the process returns to the base routine without performing any processing until the X-axis pulse distribution is completed. Return. As a result, the pulse distribution process based on the subprogram is interrupted until the retraction process of the grinding wheel G based on the main program is completed, and the pulse distribution process to the When the process is completed and the data indicating that pulse distribution to the X-axis is being executed is cleared from the interlock table IRT, pulse distribution to the X-axis based on the subprogram is started, and the position of the grinding wheel G is corrected. It will be done.

When this is completed, the execution of the subprogram is completed and the numerical control device 10 enters a standby state.

Thereafter, each time the start switch is pressed, the above operation is repeated, and the workpiece is machined and the grinding wheel is corrected. However, since the grinding wheel is corrected in parallel with the retreating movement of the grinding wheel G, the subsequent processing can be started immediately. The machining efficiency can be improved.

As described above, in the present invention, a storage means is provided for storing a numerical control program programmed for each of a plurality of control axes that need to be operated independently of each other, and a storage means is provided for each of a plurality of control axes. A pulse generation circuit is provided that can perform pulse distribution independently of each other in response to pulse distribution command data inputted by the controller, and can independently send out the completion of pulse distribution, and when a main start command is given, one control axis Only the pulse distribution process for the axis is performed according to the corresponding numerical control data, and from the time this numerical control data is executed up to a predetermined step, the pulse distribution for other control axes is also performed simultaneously according to the other numerical control data. This makes it possible to simultaneously distribute pulses to a plurality of control axes that operate independently from each other from a predetermined point in time, making it possible to use such a numerical control device in machine tools such as grinders. In some cases, there is an advantage that other operations can be performed during the return operation of the tool, significantly shortening the machining cycle time.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a block diagram showing the overall configuration of a numerical control device together with a schematic configuration diagram of a grindstone head, and FIGS. FIG. 3 is a diagram showing a detailed circuit of the sequence control circuit 16 of FIG. 1, and FIG. 4 is an example of a grinding cycle. Cycle diagrams shown in Figures 5a, b and 6
This figure is a flowchart showing the operation of the arithmetic processing unit 11 in FIG. 1, and FIG. 7 is a time chart showing the temporal relationship between pulse distribution to each axis and processing for performing the pulse distribution. 10... Numerical control device, 11... Arithmetic processing device, 12... Memory, 13a, 13b... Pulse generation circuit, 15... Program writing device, 20
a, 20b...Speed register, 21a, 21b...
...oscillator, 22a, 22b...preset counter, 23a, 23b...gate circuit, DT...correction tool, G...grinding wheel, W...workpiece.

Claims (1)

[Claims] 1. In a numerical control device that controls the operation of a machine tool by distributing pulses to multiple control axes, multiple numerical controls each define the movement of multiple control axes that should be operated independently of each other. A storage means for storing data and a plurality of control axes to be operated independently perform pulse distribution independently from each other according to the input distribution data, and when the distribution is completed, the distribution is completed independently from each other. Each time a distribution completion signal is sent from a plurality of pulse generation means for sending signals, and from a pulse generation means corresponding to a specific axis among the plurality of control axes when only the first start command is given. Then, distribution data based on the corresponding numerical control data is set in the pulse generating means to which the distribution completion signal is sent, and when both the first start command and the second start command are given, the specified Each time a distribution completion signal is sent from either the axis of and timing control means for generating the second start command in response to execution of the numerical control program corresponding to the specific control axis to a predetermined position. numerical control device.