JPS62120901A - Face lathe - Google Patents

Abstract

PURPOSE:To perform accurate face cutting keeping cutting speed constant by operating the revolving speed of a main spindle on the basis of the signals from a detector for detecting the position of a cutter in a radial direction and the setting value of a cutting speed setting device and controlling the revolving speed of the main spindle. CONSTITUTION:A tool rest 7 is set in such a way that a cutter 8 is positioned at the end of a work face 1', and a cutting speed is set by a cutting speed setting device 14, and the distance (r) from the cutter 8 to the center of the work face 1' is detected by a position detector 13 and input in a controller 6. On the other hand, when a feed motor 10 is driven to move the tool rest 7 through a master screw 9 starting cutting, feed rate signals are input in the controller 6. The variation of the position (r) of the cutter 8 is input in the controller 6 through the position detector 13, and the revolving speed of a workpiece 1 at which a cutting speed is kept constant is computed, and the feed rate signals from the feed motor 10 are subject to feedforward, thereby a d.c. motor 4 being controlled in rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a face lathe, and particularly to a face lathe that has a constant cutting speed and is capable of precision face cutting.

[Technical background of the invention and its problems] Conventional face lathes rotate a workpiece fixed to a chuck fixed to the main spindle by rotating the main spindle using a DC motor.

A blade placed opposite the workpiece is moved along the surface of the workpiece using a pulse motor to perform face milling, and at this time, the rotational speed of the workpiece is equal to the rotational speed of the DC motor that is being cut. Since it is the same and constant, the cutting speed will decrease as the cutting tool moves from the edge of the workpiece to the center. Such changes outside the cutting wheel are negative for face milling, which requires high precision.

[Purpose of the invention] The present invention was made in view of the above-mentioned conventional difficulties.

It is an object of the present invention to provide a face lathe capable of precise face cutting at a constant cutting speed.

[Summary of the Invention] In order to achieve such an object, the face lathe of the present invention includes a chuck for fixing a workpiece, a main shaft rotation motor for rotationally driving the chuck, and a cutter that moves along the lathe surface of the workpiece. , and a position detector for detecting the position of the cutter in a face lathe having a feed motor for moving the cutter.

A cutting speed setter that presets the cutting speed, and a rotation speed of the main shaft of the chuck is calculated based on a detection signal from the position detector and a value set by the cutting speed setter, and the rotation speed of the main shaft is adjusted based on the calculation result. and a controller for controlling the motor.

[Embodiments of the invention] Next, preferred embodiments of the present invention will be described with reference to the drawings.

In the drawing, a workpiece 1 has a surface 1' to be cut and is fixed to a plane lathe by a chuck 2. chuck 2
is coaxially fixed to the main shaft 3. The main shaft 3 is rotated by a DC motor 4. A controller 6 is connected to the DC motor 4 via a rectifier 5 to control the rotation of the motor 4. On the other hand, a cutter 8 is attached to a tool rest 7 facing the cut surface 1' of the work 1. The tool rest 7 is engaged with a lead screw 9 by a screw or the like (not shown), and is connected to a feed motor 10 such as a pulse motor.
As the lead screw 9 rotates, it is driven to feed in the vertical direction in the figure. Further, a position detection scale 11 is attached along the movement section of the tool post 7.

The position detection scale 11 uses, for example, a so-called linear scale in which a large number of magnets are arranged with alternating polarities along the scale, and a detection element (11a11 devi
ce) The position is detected by the pulse generated when 12 passes. Position detection scale 11
The pulses generated by this are detected by the current position detector 13 and input to the controller 6. Furthermore, a cutting speed setter 14 is connected to the controller 6 to set a predetermined cutting speed and input it to the controller 6.

Next, the operation of the plane lathe of the present invention will be explained.

First, after fixing the workpiece 1 to the chuck 2, set the tool post 7 so that the cutter 8 is at the end of the surface to be cut 1'', and set the cutting speed setting device according to the purpose of cutting and the condition of the surface to be cut 1'. 14
A predetermined cutting speed v (m/win) is set.

The position of the cutter 8 at this time, that is, the distance r (mm') to the center of the rotating workpiece 1, is detected by the position detector 13 and input to the controller 6. controller 6
is the cutting speed ν(ra/m1n) from the cutting speed setting device 14
) and the position r (mm) of the cutter 8 based on the linear equation. 1000, where n is the number of revolutions of the workpiece 1 (r, P, n+,) The number of revolutions n of the workpiece 1 is calculated, and the DC motor 4 for rotating the main shaft is driven based on this value. In parallel with this, the feed motor IO is driven, the lead screw 9 is rotated, the tool rest 7 is moved, and cutting is started. The feed motor 10 is driven and controlled according to the condition of the workpiece surface 1 to be cut, and a feed speed signal from the feed motor 10 is input to the controller 6. As cutting progresses as the tool rest 7 moves, changes in the position r of the cutter 8 are input to the controller 6 through the position detector 13.

The controller 6 calculates the rotation speed n of the workpiece 1 based on equation (1) according to the change in r, and also feeds forward the feed speed signal bone from the feed motor ■0 to rotate the DC motor 4 for rotating the spindle. Control.

Furthermore, when the cutter 8 moves and approaches the center of the workpiece 1,
In equation (1), when r → 0, n-+■, so r
A limit is provided in the controller 6 to fix n when n becomes smaller than a certain value.

In this example, a DC motor is used to rotate the main shaft three times, and the rotation is controlled by changing the amount of current, but other control methods such as controlling by changing the number of rotations using an AC inverter are also possible. Needless to say, it is also possible.

[Effects of the Invention] As is clear from the above embodiments, the face lathe of the present invention always cuts at a constant cutting speed, making it possible to perform highly accurate machining.

[Brief explanation of drawings] The drawing shows an embodiment of the face lathe of the present invention. 1... Work 2...Chuck 3・・・・・・・・Main shaft ４・・・・・・・・・DC motor 6..... Controller 7・・・・・・・・・Turret 8...... cutlery 10...Feed motor 11...Position detection scale 13...Position detector

Claims (1)

[Claims] In a face lathe having a chuck for fixing a workpiece, a spindle rotation motor for rotationally driving the chuck, a cutter for moving along the lathe surface of the workpiece, and a feed motor for moving the cutter, the position of the cutter is a position detector for detecting the cutting speed, a cutting speed setter for setting the cutting speed, and calculating the rotation speed of the main shaft of the chuck based on the detection signal from the position detector and the set value of the cutting speed setter,
A face lathe comprising: a controller that controls the spindle rotation motor based on a calculation result.