JP2016062175A - Drive control device of machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce energy consumption of a machine tool when machining a workpiece and reduce work burden when creating a machining program without sacrificing a machining time and machining quality in a drive control device of a machine tool machining by executing a plurality of machining programs in parallel on a same machine, while synchronizing at a position of a synchronous code described in the machining program.SOLUTION: The drive control device of a machine tool executing respective machining programs, while intermittently synchronizing at each machining system, namely, a synchronous position when machining a workpiece: automatically measures a wait time at the synchronous position for each machining system; and automatically updates an acceleration/deceleration time of fast-forward (positioning) motion of each machining system so as to eliminate the wait time.SELECTED DRAWING: Figure 3

Description

  The present invention includes a machine tool that performs machining by executing a plurality of machining programs in parallel on the same machine while synchronizing at the position of a synchronization code described in the machining program, for example, a multi-axis drilling machine, and a plurality of turrets. The present invention relates to an operation control device such as a lathe and a machining center equipped with a plurality of tool spindles, and relates to a technology that enables energy-saving operation of such a machine tool.

  In a machine tool equipped with multiple machining means, a machining program is created for each machining system, and in parallel with the machining of other machining systems at the position of the synchronization code described in each machining program. Processing is performed. In the machining program, a large number of machining operations and auxiliary operations are described in the order of operations.

  For example, in a lathe equipped with a plurality of tool rests, a machining program is created for each tool rest. When one operation described in the middle of a machining program for a tool post cannot be executed unless the other operation described in the machining program for the other tool post is completed, before the one operation of the machining program A synchronization code is described after the other operation of the other machining program, and the one that reaches the position of the synchronization code waits for the other to reach the other and the two machining programs are synchronized.

  In creating a machining program, the processing time is reduced by allocating multiple machining operations necessary for manufacturing the target workpiece so that the machining time of each system is as uniform as possible. Therefore, it is impossible to make the processing time of each system the same.

  For example, in a lathe equipped with two turrets, if one turret is a turret turret dedicated to turning and the other turret is equipped with a rotary tool such as a drill or a milling tool and a turning tool, For workpieces with a lot of machining, it is inevitable that the waiting time of the tool post dedicated to turning increases.

  Further, in the case of a two-spindle opposed lathe having two spindles on the same axis, the distribution of machining operations becomes more complicated. In the two-spindle facing lathe, while one of the spindles is stopped and a drilling process or a plane process is being performed with a rotary tool, the workpiece held by the other spindle can be turned. Therefore, considering the workpiece delivery timing between the two spindles, select which machining operation is to be performed on which turret with which turret so that the waiting time at the synchronized position of each turret is minimized. However, a machining program must be created, and the work burden at the time of creating the machining program becomes very large.

  As described above, when creating a machining program for a machine tool having a plurality of machining systems, the machining operation is appropriately distributed to each machining system so that the expected waiting time at the synchronized position is as short as possible. Set the machining speed and rapid feed speed so that the workpiece can be machined efficiently.

  However, there are a wide variety of workpieces. For workpieces with complex shapes, a large number of synchronization positions are set in each machining program, and a large number of machining operations are performed between the front and rear synchronization positions. In order to minimize the waiting time to be generated, a great deal of labor is required to create a machining program, and it is inevitable that a certain amount of waiting time is generated at each synchronization position.

  Further, the machining program may be modified according to the result of the test machining, for example, to slightly reduce the finishing machining speed in order to increase the finished surface accuracy. If such a correction is made, the waiting time at the subsequent synchronization position will also change, and efforts to minimize the waiting time when creating the machining program will be attributed to water bubbles.

  On the other hand, considering the energy consumption in the machine tool, it is desirable to accelerate and decelerate the spindle and the tool post as slowly as possible. The tool post, the spindle and its drive mechanism are made rugged in order to achieve high machining accuracy and have a large mass. Therefore, by slowly accelerating / decelerating, it is possible to reduce the inertia load applied to the spindle motor and the turret feed motor during acceleration / deceleration.

  This machine reduces the energy consumed by machine tools when machining workpieces and reduces the work burden when creating machining programs without sacrificing machining time or machining quality in machine tools equipped with multiple machining systems. The challenge is to make it possible.

  In the present invention, each machining system at the time of workpiece machining, that is, automatically measuring the waiting time at the synchronization position for each machining system executing a different machining program while synchronizing intermittently at the synchronization position, and waiting time The above-mentioned problem is solved by automatically updating the acceleration / deceleration time of the rapid traverse (positioning) operation of each machining system so as to eliminate the problem.

  The operation control device of the present invention includes a plurality of machining systems, for example, a plurality of tool spindles and tool rests 21 (21a, 21b) and drive sources 25 (25a, 25b), 26 (26a, 26b) for individually operating them. And an operation control device provided in a machine tool including a machining program P (Pa, Pb) for each machining system including a synchronization code. Each machining system executes the machining programs Pa and Pb while synchronizing with other machining systems at the positions of the synchronization codes M100, M200, M300... Of the machining programs Pa and Pb.

  In the present invention, for each machining system, the number of fast-forwarding operations between the synchronization codes of the machining program during the execution of the machining programs Pa and Pb, that is, the fast-forwarding performed between the preceding and succeeding synchronization codes described in the machining program. Counting means 33 (33a, 33b) for counting the number of operations n, time measuring means 32 (32a, 32b) for measuring waiting time t waiting for synchronization of other machining systems during synchronization, and time constant updating means Ps I have.

  The time constant update means Ps registers in the NC device a time constant update program Ps for updating the acceleration / deceleration time during the fast-forwarding operation performed between the synchronization codes based on the waiting time t and the number n of fast-forwarding operations. This can be realized by calling the time constant update program Ps from the programs Pa and Pb.

  In a machine tool equipped with a general NC device, a counting means 33 for counting the number of fast-forward operations is provided in the programmable control unit 31 of the NC device, and a time measuring means 32 and a time constant updating means Ps are provided in the NC unit of the NC device. 30 is practically preferable.

  The update of the acceleration / deceleration time based on the waiting time t and the number n of fast-forwarding operations is a time obtained by adding a time Δt obtained by dividing the measured waiting time t by twice the number n of fast-forwarding operations. Is easy and reasonable to set the acceleration / deceleration time after the update, the calculation time can be extremely shortened, and the update operation can be performed instantaneously.

  When the acceleration / deceleration time for changing the rotation speed of the workpiece is set in the machining program, the time Δt obtained by dividing the waiting time t by the number n of fast-forwarding operations is added to the already set acceleration / deceleration time. It is better to set the time to be the acceleration / deceleration time after the update. This is because acceleration / deceleration of the workpiece rotation is performed at the time of rapid feed of the tool position, and acceleration and deceleration are performed at the rapid feed, whereas at the time of changing the workpiece rotation, either acceleration or deceleration is performed.

  In a two-spindle opposed lathe equipped with two workpiece spindles 10f and 10g facing the same tool L on the same axis L as each of the plurality of tool rests 21a and 21b, when performing machining while delivering the workpiece w between the two spindles, When creating machining programs Pa and Pb for each tool post, the distribution of machining operations such as which machining operation is performed in cooperation with the work spindle on which side becomes complicated, and the number of times of synchronization during machining also increases. The effect of reducing the work load at the time of creating a machining program by adopting this control device is remarkable.

  The rapid traverse operation of the tool post that positions the tool at the start position of the next machining operation is the most frequently performed operation during workpiece machining, and the movement speed is much faster than when the workpiece is actually machined. Therefore, the energy consumed during the acceleration / deceleration is large.

  In this invention, the waiting time for each machining system is automatically measured while machining the workpiece, and the acceleration / deceleration time of the fast-forwarding operation can be automatically updated so that the waiting time is minimized. Energy consumption can be reduced. In this invention, since the machining operation for actually machining the workpiece is not affected, there is an effect that the energy consumption of the machine tool at the workpiece machining can be reduced without sacrificing the machining time or machining quality.

  Further, according to the present invention, even when the estimated machining time at the time of creating the machining program is rough, or even when the machining program is modified after the machining of the workpiece is started, the machining program is arranged so that the energy consumption is minimized. Since the correction is made, there is an effect that the work load at the time of creating the machining program is reduced.

Block diagram showing an example of a machine tool to which the present invention is applied Diagram showing examples of machining program code description Flow chart showing an example of an acceleration / deceleration update program

  Hereinafter, an embodiment of the present invention will be described by taking a two-spindle opposed lathe equipped with two tool rests as an example. FIG. 1 is a schematic block diagram of a two-spindle opposed lathe equipped with two turret tool rests, 10f and 10g are the left and right spindles on the same spindle axis L, and 11f and 11g support the respective spindles. The left and right headstocks 12f and 12g are left and right work chucks mounted on opposite ends of the left and right main spindles 10f and 10g. The left spindle stock 11f is provided at a fixed position, and the right spindle stock 11g can be moved and positioned in the Z-axis direction parallel to the spindle axis L.

  After the workpiece w is gripped by the left chuck 12f and processed on the left spindle 10f side, the right spindle 11g approaches and separates from the left spindle 11f side, and the right chuck 12g at the approached position. The left chuck 12f is switched to the right chuck 12g by the workpiece gripping operation and the workpiece releasing operation of the left chuck 12f, and then the next workpiece is supplied to the left chuck 12f. The workpiece that has been processed on the right spindle 10g side is discharged out of the machine as a finished product.

  21a and 21b are turret tool rests arranged on both sides of the spindle axis L, and a plurality of tools T are mounted on the turrets 22a and 22b, respectively. The tool rests 21a and 21b have long movement strokes in the Z-axis direction that can machine both the workpieces w gripped by the left and right workpiece chucks 12f and 12g.

  If the turret 22a is a rotating tool turret capable of mounting a rotating tool such as a drill or a milling cutter, and the turret 22b is a turret mounting only a turning tool, the turret 22a has a rotating tool necessary for machining the workpiece w. The turning tool is mounted on the remaining tool mounting portion of the turret 22a and the turret 22b. Which of the turning tools necessary for machining the workpiece w is mounted on the turret 22a and which is mounted on the turret 22b is determined by how the machining operation is distributed to the turrets 22a and 22b.

  Spindle motors 13f and 13g for rotationally driving the respective spindles 10f and 10g are mounted on the left and right spindle stocks 11f and 11g. The tool rests 21a and 21b are provided with respective Z-axis feed motors 25a and 25b and X-axis feed motors 26a and 26b via feed screws 23a, 23b and 24a and 24b in the Z-axis direction and the X-axis direction. Yes.

  The NC device 3 that controls the rotation of the spindle motors 13f and 13g and the movement positions of the tool rests 21a and 21b in the Z-axis and X-axis directions includes an NC unit (numerical control unit) 30 and a PC unit (programmable control unit) 31. And. A machining program Pa for the tool rest 21a and a machining program Pb for the tool rest 21b are registered in the NC unit 30. The NC unit 30 includes timers 32a and 32b that measure the waiting time at the synchronization position of each machining program, and a time constant update program Ps that rewrites the acceleration / deceleration time during fast-forwarding. The PC unit 31 includes counters 33a and 33b that count the number of fast-forward operations for the tool rests 21a and 21b, respectively. The operation panel 34 of the NC device 3 is provided with an energy saving operation mode setting switch 35.

  The machining programs Pa and Pb control the positions and movement speeds in the Z-axis and X-axis directions for the tool rests 21a and 21b, respectively. At the time of workpiece machining, the spindle rotational speed at the time of machining is also set as necessary. The machining program includes codes for setting the acceleration / deceleration time constant for the rapid traverse operation of the tool post and the acceleration / deceleration time constant for changing the spindle rotation.

  Auxiliary function code M100, M200, M300 ... is used as the waiting code for the first, second, third, etc. code to set the time constant for acceleration / deceleration of the tool post and fast acceleration / deceleration of the spindle Is G10, the code for calling the time constant update program Ps is M50, and a plurality of machining operations performed between the waiting codes are collectively displayed as O100, O200, O300... The programs Pa and Pb are described as shown in FIG. O100, O200, and O300 include a plurality of fast-forward commands (positioning codes, usually G00). In the M50 code that calls the time constant update program Ps, the line number of the immediately preceding G10 code (XX, ΔΔ is written with a number) is specified as an argument passed to the time constant update program. Yes.

  The procedure of the time constant update program is shown in FIG. When the program is called, it is determined whether or not it is in the energy saving operation mode, and if it is not in the energy saving operation mode, the process ends without doing anything. The energy saving operation mode is set by the setting switch 35 on the operation panel. In the energy saving operation mode, the waiting time measured by the timer 32a or 32b is acquired according to which turret machining program the machining program that called the time constant update program is. If the waiting time is less than or equal to the threshold value, the processing is terminated without doing anything because there is no waiting time.

  In the energy saving operation mode, if the waiting time is greater than the threshold value, the count number n of the counter 33a or 33b is acquired according to which tool post the machining program that called the time constant update program is. Then, the waiting time t is divided by twice the number n of fast-forwarding times (acceleration and deceleration are performed in one fast-forwarding), and a margin time Δt for one acceleration / deceleration is calculated. The set value of the time constant of the G10 code is rewritten so as to be a time obtained by adding the calculated extra time to the acceleration / deceleration time set in the G10 code of the line number passed by the argument.

  If the time constant for acceleration / deceleration of the spindle rotation is set in the G10 code, the time constant is accelerated / decelerated by twice the time Δt, which is the time obtained by dividing the timer time t by the counter count value n. Rewrite the time constant so that the time is extended. This is because the acceleration / deceleration of the spindle is usually performed during the rapid feed operation of the tool post, and the spindle is accelerated or decelerated during a single rapid feed operation involving the acceleration and deceleration of the tool post.

  Then, the counter 33a or 33b and the timer 32a or 32b that have acquired the count number and the waiting time are reset and finished, and the process returns to the machining program.

  If the set value of the G10 code is updated every time the workpiece is processed according to the above procedure, in the processing after the update, rapid feed between the waiting codes and acceleration / deceleration of the spindle rotation are performed with the updated time constant. . This update is performed in such a way that the waiting time is eliminated, and therefore acceleration / deceleration is performed slowly, so that the energy consumption is always updated so as to reduce the energy consumption immediately.

  The embodiment described above is for a lathe provided with two turrets, but the present invention can also be implemented in a lathe provided with three or more turrets. In a lathe equipped with three or more tool rests, there are cases where synchronization is made between two tool rests, or synchronization is made with three or more tool rests, but in any case, for each tool rest, Since the number of rapid traverses and the waiting time of the tool post are measured, the acceleration / deceleration set value may be updated for each tool post in the above procedure.

  In the above embodiment, the time constant update program is executed immediately after waiting at the synchronization position is completed. Since the execution time of the time constant update program is extremely short, there is generally no possibility that the processing time will be delayed by executing this program, but if the time constant is rewritten before the next processing is performed, So, if a counter and a timer are prepared for each synchronization position and memorized for one machining cycle, the time constant update program can be executed at the same time when the workpiece is loaded and unloaded. You can also.

10f, 10g Work spindle 21 (21a, 21b) Tool post 25 (25a, 25b) Z-axis feed motor 26 (26a, 26b) X-axis feed motor 30 NC part 31 Programmable control part 32 (32a, 32b) Timer 33 (33a) 33b) Counter L Spindle axis M100, M200, M300 Sync code n Rapid feed acceleration / deceleration count P (Pa, Pb) Machining program t Wait time w Work Ps Time constant update program Δt Time to extend acceleration / deceleration

Claims (5)

A machining program for each machining system including a plurality of machining systems and a synchronization code, and each machining system executes each machining program while synchronizing with other machining systems at the position of the synchronization code of the machining program. In an operation control device for a machine tool having a plurality of machining systems,
For each machining system, a counting means for counting the number of fast-forwarding operations between synchronous codes of the machining program during execution of the machining program;
A time measuring means for measuring a waiting time waiting for synchronization of another processing system at the time of synchronization,
The NC device for controlling the machine tool includes time constant updating means for rewriting a time constant of acceleration / deceleration during a fast-forward operation performed between the synchronization codes based on the waiting time and the number of fast-forward operations.
Operation control device for machine tools.   The operation control device for a machine tool according to claim 1, wherein the counting means is provided in a programmable control unit of the NC device.   The time constant updating means for rewriting the acceleration / deceleration time constant of a fast-forward command described between the synchronization codes of a machining program based on a value obtained by dividing the waiting time by twice the number of fast-forward operations. Item 3. The machine tool operation control device according to Item 1 or 2.   The time constant updating means for rewriting an acceleration / deceleration time constant of a spindle acceleration / deceleration command described between the synchronization codes of a machining program based on a value obtained by dividing the waiting time by the number of fast-forward operations. The operation control device for a machine tool according to 1, 2 or 3.   The operation control device for a machine tool according to claim 3 or 4, wherein the machine tool is a two-spindle opposed lathe provided with two spindles opposed to a plurality of tool rests on the same axis.

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