JP2588610B2 - Synchronous tapping control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control method for performing synchronous tapping on a numerically controlled (NC) machine tool.

(Prior art) Fig. 5 shows an NC that realizes a conventional synchronous tapping control method.
FIG. 3 is a block diagram showing an example of the apparatus, in which a synchronous tapping command SA stored in an operation memory 2 is read and interpreted by a program interpreting unit 1, and a feed axis / spindle target value calculating unit 3 calculates a feed axis target. The value SB and the target value SC of the spindle are obtained and sent to the feed axis function generator 5 and the spindle function generator 4, respectively. The spindle command value SD is obtained in accordance with the spindle target value SC sent by the spindle function generator 4 and sent to the spindle position controller 6 to control the drive of the spindle motor 8. At the same time, the feed axis command value SE is obtained in accordance with the feed axis target value SB sent by the feed axis function generator 5, and is sent to the feed axis position controller 7 to control the drive of the feed axis motor 10. . Then, the spindle is subjected to position feedback control by the pulse generator 9, and the feed shaft is subjected to position feedback control by the detector 11. Further, the deviation of the spindle position error SF, that is, the difference between the command value obtained by the spindle function generator 4 and the current value from the pulse generator 9 is converted by the feed axis direction unit converter 12 into synchronization between the spindle and the feed axis. It is converted into a unit (length) in the feed axis direction as an error correction value, and a deviation between the converted value and the command value SE obtained by the feed axis function generator 5 is obtained.

In such a configuration, the operation will be described with reference to the flowchart of FIG. 6 of the operation example. The program interpretation unit 1 checks whether or not synchronous tapping is being performed (step S1), and if synchronous tapping is being performed (PSYCNT = 1). ), Synchronous tapping control is performed (step S4). If synchronous tapping is not being performed (PSYCNT = 0), the process waits for synchronous tapping to start (step S2). When a synchronous tapping start command is detected, synchronous tapping is performed (PSYCNT = 1) (step S3), and synchronous tapping control is performed. (Step S4).
Then, it waits for the completion of the synchronous tapping (step S5),
When the synchronous tapping end command is detected, the synchronous tapping is canceled (PSYCNT = 0) (step S6), and the above-described operation is repeated.

(Problems to be Solved by the Invention) In the above-mentioned conventional synchronous tapping control method, the rotational angle position of the main shaft and the rotational angle position of the tap have a correlation with a certain difference. Because it can be mounted at the rotation angle position,
The difference may change before and after the tap is changed. Also, since the approach distance, which is the moving distance of the feed shaft from the start of the synchronous control to the start of the cutting of the workpiece, is the product of the tap pitch and the spindle speed, it is necessary to change the approach distance or change the pitch. If tapping is performed with different taps, the spindle speed may change. Therefore, in any of the above-mentioned cases, the starting rotational angle position of the thread changes every tapping, and it is difficult to rework the same portion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a synchronous tapping control method capable of always maintaining a constant start rotation angle position of a screw thread for each tapping.

(Means for Solving the Problems) The present invention relates to a control method for performing synchronous tapping on an NC machine tool. The object of the present invention is to provide a method of controlling a spindle rotational angle position which is an angle of a spindle and an angle of a tap. A correlation with a certain tap rotation angle position was set as an offset value, the tap rotation angle position was determined by the detected spindle rotation angle position and the offset value, and the spindle was stopped at the determined tap rotation angle position. Later, tapping is performed by synchronously controlling the main shaft and the feed shaft at the tap rotation angle position. Further, an approach distance and a tap pitch, which are moving distances of the feed shaft from the start of the synchronous control of the main spindle and the feed shaft to the start of the cut of the workpiece, are designated, and the cut into the workpiece is designated. The tap rotation angle position at the time of starting the synchronous control between the spindle and the feed axis is determined by the tap rotation angle position when starting and the approach distance and the pitch of the tap, and the spindle is positioned at the determined tap rotation angle position. Is stopped, the tapping is performed by synchronously controlling the main shaft and the feed shaft at the tap rotation angle position.

(Operation) According to the synchronous tapping control method of the present invention, the predetermined tap rotation angle position is determined, the spindle is stopped at the determined tap rotation angle position, and then the synchronous control between the spindle and the feed shaft is started. The starting rotational angle position of each screw thread can always be kept constant.

(Embodiment) FIG. 1 realizes a synchronous tapping control method of the present invention.
FIG. 6 is a block diagram showing an example of the NC device in correspondence with FIG. In order to keep the tap rotation angle position at the start of synchronous control between the main shaft and the feed shaft in a fixed direction, this NC device is configured to determine the difference between the main shaft rotation angle position, which is the main shaft angle, and the tap rotation angle position, which is the tap angle. The offset value of the relative relationship is stored in the offset storage memory 18 via the offset setting processing unit 17. Then, as shown in FIG. 2, the spindle rotation angle position SP from the pulse generator 9 is offset by the offset value SO from the offset storage memory 18 and converted into a tap rotation angle position SQ by the offset processing unit 19, and the spindle rotation is performed. It is sent to the position stop control unit 13, the switching circuit 16, and the spindle position control unit 6. Further, in order to set the tap rotation angle position at the time of starting the cut into the workpiece in a fixed direction, the spindle fixed position stop position determining unit 20 uses the program interpreting unit 1 to start the cut into the workpiece. The tap rotation angle position SS at the start of synchronous control between the spindle and the feed axis is obtained from the tap rotation angle position and the command SR consisting of the specified approach distance and tap pitch, and is sent to the spindle constant position stop control unit 13. Is done. At the same time, the spindle fixed position stop sequence setting command SH
Is sent from the program interpretation unit 1 to each of the switching circuits 14, 15, and 16. The tap rotation angle position SS from the spindle fixed position stop position determination unit 20 and the synchronous tapping command SA from the switching circuit 14.
The spindle fixed position stop operation command SI is obtained by the spindle fixed position stop control unit 13 and sent to the spindle position control unit 6 via the switching circuit 15 to stop the spindle fixed position stop at the tap rotation angle position SS. The operation is performed. Then, based on the tap rotation angle position SQ from the offset processing unit 19, a spindle fixed position stop operation end signal SJ is sent from the spindle fixed position stop control unit 13 to the program interpretation unit 1, and a synchronous tapping control sequence setting command SK is issued. The signals are transmitted to the switching circuits 14, 15, and 16.

According to the conventional synchronous tapping control method, for example, as shown in FIG. 3, the starting rotation angle position of the thread is shifted for each tapping, whereas according to the synchronous tapping control method of the present invention, as shown in FIG. In addition, the starting rotation angle position of the thread at each tapping can be kept constant.

(Effects of the Invention) As described above, according to the synchronous tapping control method of the present invention, the start rotation angle position of the thread for each tapping can be always kept constant, so that the tap is replaced or the same part is reworked. In this case, there is no need to change the program, and the time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 shows an NC for realizing the synchronous tapping control method of the present invention.
FIG. 2 is a block diagram showing another example of the device, FIG. 2 is a diagram showing an example of an offset by the method, FIG. 3 is a sectional view showing an example of tapping by a conventional synchronous tapping control method, and FIG. FIG. 5 is a cross-sectional view showing an example of tapping by a tapping control method, FIG. 5 is a block diagram showing an example of an NC apparatus for realizing a conventional synchronous tapping control method, and FIG. 6 is a flowchart for explaining an operation example. 1 ... Program interpreter, 2 ... Operation memory, 3 ...
Feed axis / spindle target value calculator, 4 ... Spindle function generator, 5
... Feed axis function generator, 6 ... Spindle position controller, 7 ...
Feed axis position controller 8, spindle motor 9, pulse generator 10, feed axis motor 11, detector 12,
... Feed axis direction unit conversion unit, 13 ... Spindle fixed position stop control unit, 14,15,16 ... Switching circuit, 17 ... Offset setting processing unit, 18 ... Offset storage memory, 19 ... Offset processing unit, 20 ... Spindle fixed position stop position determination unit.

Claims (2)

(57) [Claims] A correlation between a spindle rotation angle position, which is an angle of a spindle, and a tap rotation angle position, which is a tap angle, is set as an offset value, and the tap is determined based on the detected spindle rotation angle position and the offset value. After the rotation angle position is determined, the spindle is stopped at the determined tap rotation angle position, and the tapping is performed by synchronously controlling the spindle and the feed shaft at the tap rotation angle position. Tapping control method. 2. An approach distance and a tap pitch, which are movement distances of the feed shaft from the start of synchronous control of the main spindle and the feed shaft to the start of cutting of a workpiece, are specified.
The tap rotation angle position at the time of starting the synchronous control of the main shaft and the feed shaft by the tap rotation angle position when starting the cut into the workpiece and the approach distance and the pitch of the tap is obtained, and the obtained tap is obtained. A synchronous tapping control method, wherein after the spindle is stopped at a rotation angle position, tapping is performed by synchronously controlling the spindle and the feed shaft at the tap rotation angle position.