JPS61146451A - Feed controlling method of turning shaft in machine tool - Google Patents

Abstract

PURPOSE:To make undue variations so as not to be produced in a cutting speed, by varying a feed angular velocity in a turning shaft according to a distance of a turning tool from the turning center of a work, and thereby keeping a tangential velocity of the turning tool, during operation, constant all the time. CONSTITUTION:There is provided with a tool position detecting device such as a transducer 17, a tool feed control part 5, etc., detecting the existing position LN of a turning tool 15, and on the basis of the existing position LN of the turning tool 15 to be outputted out of the said detecting device, a distance (r) ranging from a Z-axis or the turning center of a work 16 to the turning tool 15 is found. According to this distance (r) and the inputted tangential velocity FVC, a turning shaft of a spindle 12 is rotated at such an angular velocity FVtheta as making the tangential velocity in time of machining the work 16 by the said turning tool 15 constant. Therefore, machining of the work 16 by the turning tool 15 is controlled so as to keep the tangential velocity constant all the time even if the distance (r) varies, so that undue variations in a cutting speed will no longer happen there, thus the work 16 is machinable in good conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for controlling the feed of a rotating shaft that supports a workpiece during machining in a lathe or machining center having a milling function.゛(b), Conventional technology Conventionally, in this type of machine tool, the feed rate of the rotary axis was instructed to the machine tool by a programmer who calculated an appropriate feed angular rate from the diameter of the workpiece to be machined. .

(C) 0 Problems to be Solved by the Invention However, this does not matter if the distance of the machined part from the rotation center of the workpiece is constant, but if the distance changes during machining ( When cutting a straight groove on the end face of a workpiece with a lathe), if the angular velocity is controlled to be constant, the cutting speed will change significantly due to fluctuations in the distance of the cutting part from the workpiece rotation center, making it difficult to perform proper cutting operation. There was an inconvenience that this could not be done.

In order to eliminate the above-mentioned drawbacks, the present invention provides a method for controlling the feed of a rotary axis in a machine tool, which does not cause excessive fluctuations in cutting speed even if the distance between the rotation center of the tool and the workpiece changes. The purpose is to provide

(d) Means for solving the zero problem, that is, the present invention provides a tool position detection means for detecting the current position of a rotary tool, and detects the workpiece from the current position of the rotary tool output from the tool position detection means. Find the distance from the center of rotation to the rotary tool, and from the requested distance and the input tangential speed, rotate the rotary shaft at an angular velocity such that the tangential speed when machining the workpiece with the rotary tool is constant. It is configured in such a way that

(e) 0 effect With the configuration described above, the present invention changes the feed angular velocity of the rotary shaft according to the distance of the rotary tool from the rotation center of the workpiece, thereby making the tangential speed of the rotary tool constant during machining. It works like this.

(f), Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a control block diagram showing an example of a corresponding part of a machine tool to which the rotary shaft feed control method according to the present invention is applied.

As shown in FIG. 1, the machine tool 1 has a main control section 2, and a keyboard 3 is connected to the main control section 2 via a bus line 4.
, a tool feed control section 5, a feed rate calculation section 6, and a rotary axis feed control section 7 are connected.

The tool feed control unit 5 is connected to feed shaft drive motors 9 provided for the X-axis and Z-axis, which are the directions in which the tool holding table 1o described below is to be driven. A transducer 17 for detecting the rotation angle of the feed shaft drive motor 9 is connected to the tool feed control section 5 .

Further, the feed shaft drive motor 9 is capable of movably driving a tool holding table 10 in the directions of arrows A and B, that is, the X-axis direction, and in the directions of arrows C and D, that is, the Z-axis direction, through appropriate means such as a ball screw. A rotary tool 15 such as a milling cutter is rotatably mounted on the tool holder 10. In addition, the rotating shaft feeds 1tl! II! A rotary shaft feed drive motor 11 is connected to the 11 section 7, and a spindle 12 is rotatably provided on the rotary shaft feed drive motor 11 via an appropriate speed reducer (not shown). A work holding device 13 such as a chuck is provided on the spindle 12 so as to be rotatably driven around a main axis, that is, the Z axis, and a cylindrical work 16 is mounted on the work holding device 13.

Since the machine tool @ 1 has the above configuration, the workpiece 16 is moved by the rotary tool 15 held on the tool holder 10.
When cutting a groove or the like on the end face 16a of the Machining is performed by applying feed in a manner that the On this occasion,
The tangential speed FVC during machining is specified from the keyboard 3 or the like by an operator's instruction or a cutting program, etc. In response to this, the feed rate calculation section 6 calculates the current position of the rotary tool 15 in the X-axis direction, that is, the workpiece. The feed shaft drive motor 9
is controlled so that the tangential speed during machining of the workpiece 16 by the rotary tool 15 remains constant regardless of changes in the distance r.

On the other hand, the tool feed control unit 5 controls the feed shaft drive motor 9 to drive the tool holder 10 on which the rotary tool 15 is mounted in the directions of arrows A and B, that is, the 15, the position of the tool holder 10 and therefore the rotary tool 15 in the X-axis direction is always controlled by the tool feed control unit 5 by a transducer 17 attached to the feed shaft drive motor 9. . Therefore, the feed rate calculation unit 6 reads the current position LN of the rotary tool 15 in the X-axis direction from the tool feed control unit 5 by periodically polling, and from the read current position LN, the Z Find the distance r in the X-axis direction from the axis, and from the distance glr,
According to equation (1), the workpiece 16 at the position of the rotary tool 15 in the X-axis direction, and therefore the spindle 12 which is the rotation axis
Find the angular velocity FVθ.

Fve = - The motor 11 is driven and controlled, and the workpiece 16 is thereby moved through the spindle 12 and the workpiece holding device 13.
The rotation of the workpiece 16 is controlled so that the rotary tool 15 processes the workpiece 16 at a predetermined tangential speed FVC. The current position L of the rotary tool 15 is sent from the feed rate calculation unit 6 to the tool feed control unit 5.
Since N polling is performed periodically, even if the distance r between the rotary tool 15 and the Z axis changes as machining progresses,
An angular velocity FVe corresponding to the change is calculated, and further, based on the calculated angular velocity FVe, the rotary shaft feed drive motor 1
1 is drive-controlled, the workpiece 16 is cut in good condition while maintaining a predetermined tangential speed FVC without excessive fluctuations in cutting speed.

(g) 6 Effects of the Invention As explained above, according to the present invention, the rotary tool 15
A tool position detection means such as a transducer 17 and a tool feed control section 5 is provided to detect the current position LN of the rotary tool 15, and the current position LN of the rotary tool 15 outputted from the tool position detection means is provided.
From the Z-axis, which is the rotation center of the workpiece 16, the rotary tool 1
5, and from the requested distance r and the input tangential speed FVC, set the rotation axis of the spindle 12 etc. so that the tangential speed when machining the workpiece 16 with the rotary tool 15 is constant. Since the workpiece 16 is rotated at the angular velocity FVe, the machining of the workpiece 16 by the rotary tool 15 is controlled so that the tangential speed is always constant even if the distance r between the rotary tool 15 and the rotation center of the workpiece 16 changes. Therefore, the workpiece 16 can be machined in good condition without excessive fluctuations in cutting speed.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram showing an example of a corresponding part of a machine tool to which the rotary shaft feed control method according to the present invention is applied. 1... Machine tool 5... Position detection means (tool feed control section) 10.
... Tool holding means (tool holding stand) 12 ...
...Rotary axis (spindle) 15...Rotary tool 16...Workpiece 17...Position detection means (transducer) r
...Distance LN ...Current position FVC ...Tangential velocity FVe ...Angular velocity Applicant Yamahato Iron Works Co., Ltd. Agent Patent attorney Phase 1) Shinji (et al.) 1 person)

Claims (1)

[Scope of Claims] A rotating shaft on which a workpiece is mounted, a holding means for a rotating tool provided movably in a direction perpendicular to the rotation center of the workpiece, and the rotating shaft is rotated together with the workpiece. In a machine tool that processes a workpiece with a rotary tool held by the holding means while being fed, a tool position detection means for detecting the current position of the rotary tool is provided,
The distance from the rotation center of the workpiece to the rotary tool is determined from the current position of the rotary tool output from the tool position detection means, and from the determined distance and the input tangential speed, the rotary axis is set to the rotary tool. A method for controlling the feed of a rotating axis in a machine tool configured to rotate at an angular velocity such that the tangential velocity during machining of a workpiece is constant.