JPH11156638A - Numerical control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a numerical control device which can machine a bottom of a hole according to required accuracy of a tapping machining. SOLUTION: A numerical control device performs tapping machining while synchronously controlling a main shaft position and a feeding shaft position, through synchronizing rotational command of a main shaft 9 and a moving command of a feeding shaft 15. Such a device has followings: a time constant determination circuit 4 which determines acceleration/deceleration time constant according to a screw pitch and peripheral speed of a tap specified by an input device 1, acceleration/deceleration control circuits 5, 11 which perform acceleration and deceleration controls of the main shaft 9 and the feeding shaft 15 based on the determined acceleration/deceleration time constant, error counters 6, 12 to which output pulses of the acceleration/deceleration control circuits 5, 11 are supplied, and an error detecting area setting means 17 which optionally sets an error detecting area upon receiving command from the input device 1, and supplies the set area to the error counters 6, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a numerical control device for performing tapping processing by synchronously controlling a spindle position and a feed shaft position in a machine tool such as a machining center.

[0002]

2. Description of the Related Art A conventional numerical controller is disclosed in, for example,
As disclosed in JP-A-112322, after the pulse distribution of the movement of the feed axis is completed, the accumulated pulse allowable value (error detect on) due to the delay of the servo is fixed and cannot be variably set.

[0003]

As described above, in the conventional numerical control device, in the machining of the cut hole for tapping, the allowable value of the accumulated pulse due to the delay of the servo is fixed, regardless of the type of tapping. The bottom of the hole is machined with a certain degree of accuracy. For example, even in the case of tapping with a low accuracy, the hole bottom is machined with a certain degree of high accuracy, and a considerable amount of machining time is required. Therefore, an object of the present invention is to provide a numerical control device capable of performing a hole bottom processing according to a required accuracy of tapping.

[0004]

A numerical controller according to the present invention performs a tapping process by synchronizing a main shaft position and a feed shaft position by synchronizing a main shaft rotation command and a feed shaft movement command. The apparatus is provided with means for arbitrarily setting an error detection area due to a servo delay after the end of pulse distribution. Further, the numerical control device according to the present invention is a numerical control device that performs a tapping process by performing a synchronous control of a spindle position and a feed shaft position by synchronizing a rotation command of a spindle and a movement command of a feed shaft. Time constant determining circuit for determining an acceleration / deceleration time constant according to the selected screw pitch and peripheral speed of the tap, and acceleration / deceleration control for performing acceleration / deceleration control of the main shaft and the feed shaft based on the determined acceleration / deceleration time constant. A circuit, an error counter to which an output pulse of the acceleration / deceleration control circuit is supplied, and an error detection area setting means for arbitrarily setting an error detection area by designation from the input device and supplying the set area to the error counter. It is provided with. According to the present invention, the error detection area setting means that can be input from the input device is provided in the numerical controller. As a result, after the spindle rotation command and the feed axis movement command are pulse-distributed, it is possible to confirm that the accumulated pulse due to the delay of the servo of the error counter has reached the allowable value set by the error detection area setting means. , The machining accuracy at the bottom of the tap hole is machined with the set accuracy. That is,
The processing accuracy of the hole bottom can be arbitrarily set from the input device according to the type of the screw or the like.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a main part of a numerical control device according to the present invention. When data is input from the input device 1, the arithmetic unit 2 outputs a command value determined according to the description on the machining program based on the input data. As the command value in this case, the screw pitch p of the tap and the peripheral speed F are output. The pulse distribution circuit 3 to which the outputs p and F are input provides a distribution pulse Ps for rotating the main shaft 9.
Is output to the main shaft acceleration / deceleration control circuit, and the feed shaft 15
Is output to the feed axis acceleration / deceleration control circuit 11 for controlling the movement of the axis. The time constant determination circuit 4 includes a pitch dependent constant table as a data table of a pitch dependent constant corresponding to the screw pitch p, and is provided with the like.
The acceleration / deceleration time constant T is output to the main shaft acceleration / deceleration control circuit 5 and the feed axis acceleration / deceleration control circuit 11 according to the screw pitch command value p input from the arithmetic unit 2. Spindle acceleration / deceleration control circuit 5
Controls the acceleration / deceleration of the spindle motor 8, that is, the spindle 9, based on the distribution pulse Ps and the acceleration / deceleration time constant T. The output pulse Qs from the main shaft acceleration / deceleration control circuit 5 is sent to the main shaft error counter 6, and the error counter 6 is counted up. The feedback pulse Rs obtained from the pulse generator 10 rotating in synchronization with the main shaft 9 counts down the main shaft error counter 6. Therefore, there is a difference between the output pulse Qs and the feedback pulse Rs inside the spindle error counter 6, and this value is converted into an analog signal and given to the spindle drive circuit 7. drive. The feed axis acceleration / deceleration control circuit 11 receives the distribution pulse Pz and the acceleration / deceleration time constant T and outputs an output pulse Qz
Is output to the feed axis error counter 12, and the feed axis error counter 12 is counted up. On the other hand, the feedback pulse Rz output from the pulse generator 16 that rotates synchronously with the feed shaft 15 counts down the feed shaft error counter 12. The feed axis error counter 12 converts the difference between the output pulse Qz and the feedback pulse Rz into an analog signal and provides the analog signal to the feed axis drive circuit 13. Then, the feed shaft drive circuit 13 drives the feed shaft motor 14 to drive the feed shaft 15. According to the present invention, in such a numerical control device, an error detection area setting table for inputting data from the input device 1 and the time constant determining circuit 4 and outputting the data to the spindle error counter 6 and the feed axis error counter 12 is provided. 17 are provided. With this configuration, when the screw pitch information is input from the input device 1, the pulse distribution circuit 3, which receives the output of the arithmetic unit 2, sends the pulse acceleration / deceleration control circuit 5 for the main shaft and the acceleration / deceleration control circuit 11 for the feed shaft to the input. The distribution pulses Ps and Pz are output, and the spindle 9 and the feed shaft 15 are driven according to the machining program to perform the machining operation. On the other hand, when inputting the screw pitch information, the input device 1 automatically outputs information proportional to the hole bottom machining precision appropriate for the screw and gives the information to the error detection area setting table 17. Then, the error detection area setting table 17 outputs the set area value to the spindle error counter 6 and the feed axis error counter 12. When each of the error counters 6 and 12 confirms that the delay pulse allowable value of the servo is in the error detection area, it determines that the required processing accuracy of the hole bottom is satisfied, and ends the processing. Instead of automatically outputting the processing accuracy information when the screw pitch information is input to the input device 1, a method may be used in which both the screw pitch information and the processing accuracy information are input.

[0006]

According to the invention described above, the error detection area setting means for setting the area by the input device is provided, and its output is input to the error counters for the main spindle and the feed axis, so that the processing program Thus, the processing accuracy of the screw hole bottom can be set according to the type of screw and the like. As a result, in the case of screw processing that does not require accuracy, the accuracy of the hole bottom is not required, so if the error detection area setting value is set to a large value, processing will be performed with low accuracy, and the processing time will be shortened, The time of the tapping processing cycle can be reduced, and the production efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a numerical control device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 input device 2 arithmetic unit 3 pulse distribution circuit 4 time constant determination circuit 5 spindle acceleration / deceleration control circuit 6 spindle error counter 7 spindle drive circuit 8 spindle motor 9 spindle 10 spindle pulse generator 11 feed axis acceleration / deceleration control circuit 12 Error counter for feed axis 13 Feed axis drive circuit 14 Feed axis motor 15 Feed axis 16 Pulse generator for feed axis 17 Error detection area setting table

Claims (2)

[Claims] An error caused by a servo delay after completion of pulse distribution in a numerical control device that performs a tapping process by synchronizing a main shaft position and a feed shaft position by synchronizing a main shaft rotation command and a feed shaft movement command. A numerical control device comprising means for arbitrarily setting a detection area. 2. A numerical control device for performing a tapping process by synchronizing a spindle position and a feed shaft position by synchronizing a spindle rotation command and a feed shaft movement command. A time constant determining circuit that determines an acceleration / deceleration time constant according to a peripheral speed; an acceleration / deceleration control circuit that performs acceleration / deceleration control of the main shaft and the feed shaft based on the determined acceleration / deceleration time constant; An error counter to which an output pulse of the control circuit is supplied, and an error detection area setting means for arbitrarily setting an error detection area by designation from the input device and supplying the set area to the error counter. Numerical control device.