JPH0249857B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an NC device with an adaptive control function. [Prior art and its problems] As is well known, conventional NC equipment processes and transports workpieces by moving tools, hands, etc. faithfully in accordance with the order of the NC program. No changes are made to the NC program. Therefore, for example, in an NC machine tool, when a tool becomes dull, excessive force is applied to the blade, which may cause it to break and become impossible to machine, or the machining accuracy may drop significantly. In addition, when drilling holes, for example, if you use a manual drilling machine that manually raises and lowers the drill, if the drill becomes dull and you drill the hole while moving the drill up and down intermittently, the drill bit will become sharp. It is well known from experience that machining can be completed without chipping, and that the vertical movement of the drill must be increased as the cutting edge becomes dull. Based on this experience, conventional NC machine tools create NC programs with intermittent feed operations that take machining operations into account when the tool condition deteriorates. Therefore, when the tool condition is good, unnecessary time is wasted, and when the tool condition is worse than expected, machining becomes difficult, and in the worst case, it is necessary to change the tool in the middle of machining. Therefore, it may be necessary to interrupt the process. [Problem to be solved by the invention] In order to solve this problem, it has been proposed in the past to apply an adaptive control method to NC equipment.
In order to always make corrections to match the optimal conditions, the detection data of the condition detector is fed to the adaptive control device, and correction data corresponding to the detection data, such as feed rate, etc.
A method is being considered that calculates spindle rotational speed change data and provides it to the NC device to perform adaptive control. However, this method has problems in practical application because a different adaptive control device must be developed for each NC device and it is difficult to use, so it is not widely used. Therefore, the present invention aims to provide an NC device with an adaptive control function that does not require a conventional adaptive control device and allows easy setting of adaptive conditions. [Means for Solving the Problems] The present invention has been made to solve the above problems. A current detector that detects changes in force, etc., and a skip signal generating means that sends out a skip signal in response to the detection signal are provided, and a plurality of program blocks corresponding to changes in the NC program storage circuit are pre-installed, and the skip When a signal is generated, the program block being executed is forcibly terminated, and the program block corresponding to the skip signal is restarted.
The device is equipped with a means for instantaneous transition to the block. An embodiment in which the present invention is applied to a drilling NC machine tool will be described below with reference to the drawings. [Example] Fig. 1 shows the operation of the drill D of the drilling NC machine tool of the example, and Fig. a shows the drilling operation when the drill D (tool) is new. In this case, the drill D descends from the starting point Z ₀ to point Z ₁ (the starting point of drilling on the workpiece) by rapid traverse, and drills to the target point Z ₂ at a speed of V ₁ . When Drill D reaches point ₂ and drilling is completed,
Z Fast-return to ₀ point. Figure b shows the drilling operation when Drill D loses its sharpness midway through.It is similar to what a person would do when using a manual drilling machine when chips have accumulated and the cutting has deteriorated. Drill D is first raised and then lowered to drill the hole up to point Z ₂ , and when the drilling is completed, it quickly returns to point Z ₀ . In figure c, when the tool is bad, the drilling speed (descending speed) from point _Z1 is set to _V2 , and since the tool is bad, it will inevitably cut poorly, so as in the case of figure b, the drilling speed is set to V2. Machining is performed intermittently to point Z ₂ , and when the hole is completed, it quickly returns to the starting point Z ₀ . That is, the drilling process is performed in the shortest time depending on the condition of the tool. Next, let's explain its configuration and operation. FIG. 2 is a block diagram of the drilling NC machine tool of the embodiment. In the figure, 1 is a feed motor in the X-axis direction, 2 is a feed motor in the Y-axis direction, and 3 is a feed motor in the Z-axis direction. In the embodiment of the present invention, the feed motor 3 in the Z-axis direction is controlled according to the sharpness of the tool and external conditions to control the drill D as shown in a to c of FIG. Therefore, control regarding the feed motors 1 and 2 is not relevant here and will be omitted here. 4 is an NC program storage circuit that stores an NC program; when an execution block is designated by a command order counter 5, the execution block is read out via a command reading circuit 6, and a movement command is issued by a decoder 7; The content of is deciphered. 8 is an arithmetic circuit that performs interpolation and correction calculations from the movement command decoded by the decoder 7 to calculate the target position and feed speed, and the calculated values are sent to the servo motor control circuit via the movement command circuit 9. 10″
The servo motor control circuit 10'' controls the feed motor 3 in the Z-axis direction via the servo amplifier 11''.
control. A speed detector TG is connected to the feed motor, and the feed motor is controlled at a constant rate to match the speed command given to the servo amplifier 11'' from the servo motor control circuit 10''. The position of drill D is the pulse generator.
When the number of pulses detected by the PG and the number of pulses input from the movement command circuit 9 to the servo motor control circuit 10'' match, that is, when the target position is reached, a match signal is sent from the servo motor control circuit 10''. It is sent to the match determination circuit 12. At this time, when the command end signal is input from the movement command circuit 9 to the coincidence determination circuit 12, the coincidence determination circuit 12
A completion signal (open signal) is sent from the OR gate 13 to the AND gate 14 . When an open signal is given to the AND gate 14, the adder circuit 15 adds 1 to the current block number and gives it to the command order counter 5, and the next execution block is transferred from the command order counter 5 to the NC program storage device 4. The specified signal is sent. The above configuration and operation are the same as conventional NC machine tools. The difference from conventional NC machine tools is that it is equipped with an intelligent sensor, that is, a detector that detects changes in machining conditions. In this embodiment, in order to detect the feed reaction force and the spindle reaction force, a device for detecting fluctuations in the feed motor current and the spindle motor current was provided (not shown). Second, when the detected currents exceed a certain value, the electronic switches S ₁ and S ₂ are operated to generate the skip signals 1 and 2, respectively. Thirdly, several types of program blocks corresponding to changes in machining conditions are pre-installed. In this embodiment, in order to perform the movement in the Z-axis direction as shown in FIG. 1, an NC program is constructed as follows.

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Claims (1)

[Claims] 1 A detector that detects changes in multiple machining conditions,
In addition to providing skip signal generation means for sending out multiple skip signals according to the detection signal, the NC
The program storage circuit stores multiple programs including machining speed and reverse operation corresponding to changes in the machining state.
A program block is installed in advance, and when the skip signal is generated, the program block being executed is forcibly terminated, and the program block is immediately transferred to the program block corresponding to the skip signal, so that the program continues without interruption. An NC device with an adaptive control function that executes a program by