MACHINING VIBRATION SUPPRESSING METHOD AND MACHINING VIBRATION SUPPRESSING APPARATUS FOR MACHINE TOOL

• US 20130309034A1
• Filed: 03/11/2013
• Published: 11/21/2013
• Est. Priority Date: 05/17/2012
• Status: Active Grant

• Current Assignee: Okuma Corporation
• Original Assignee: Okuma Corporation
• Inventors: INAGAKI, Hiroshi, SHIKAMA, Toshiya
• Granted Patent: US 9,221,143 B2
• Time in Patent Office: Days
• US Class Current: 409/132
• CPC Class Codes: B23Q 11/0039 by changing the natural frequency of the system or by continuously changing the frequency of the force which causes the vibration
• CPC Class Codes: B23Q 15/013 Control or regulation of feed movement B23Q15/12 takes precedence
• CPC Class Codes: B23Q 15/08 Control or regulation of cutting velocity B23Q15/12 takes precedence
• CPC Class Codes: B23Q 17/0976 Detection or control of chatter B23Q15/12 takes precedence
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/37517 Compensation of position for vibration of probe, calibration x-y lookup table
• CPC Class Codes: G05B 2219/49176 Compensation of vibration of machine base due to slide movement
• CPC Class Codes: Y10T 409/303752 Process
• CPC Class Codes: Y10T 409/303808 including infeeding
• CPC Class Codes: Y10T 409/304312 with means to dampen vibration
• CPC Class Codes: Y10T 409/306832 with infeed control means energized in response to activator stimulated by condition sensor

Abstract

An apparatus includes an external input device that allows setting of the amount of runout and the phase of each cutting edge, a computation device that acquires the rotational phase of a tool and that computes the angular velocity and the phase of vibration of two, X-axis and Y-axis, feed shafts on the basis of the input amount of runout and angular velocity of each cutting edge to generate a feed shaft control signal, and a numerical control device that controls feed in the X-axis and the Y-axis directions. The numerical control device relatively vibrates a workpiece in synchronization with the angular velocity of the tool on the basis of the results of computation performed by the computation device.

Claims

1. A machining vibration suppressing method for a machine tool that machines a workpiece while rotating a tool mounted to a main spindle, the method comprising:

machining the workpiece while applying forced vibration at a predetermined amplitude and a predetermined frequency of vibration to feed operation for a feed shaft during machining.

2. The machining vibration suppressing method for a machine tool according to claim 1, wherein

the frequency of vibration of the forced vibration is a frequency of vibration shifted by a predetermined amount with respect to a rotation speed of the tool.

3. The machining vibration suppressing method for a machine tool according to claim 1, wherein

the frequency of vibration of the forced vibration is a frequency of vibration that is equal to a rotation speed of the tool.

4. The machining vibration suppressing method for a machine tool according to claim 2, wherein

the workpiece is machined with first vibration and second vibration superimposed on the feed operation for the feed shaft during machining, the first vibration being at a frequency of vibration shifted by a predetermined amount with respect to the rotation speed of the tool and the second vibration being at a specific amplitude and at a frequency of vibration that is equal to the rotation speed of the tool.

5. A machining vibration suppressing apparatus for a machine tool that machines a workpiece while rotating a main spindle to which a tool having one or a plurality of cutting edges are mounted to feed at least one of the workpiece and the tool in a plane that is orthogonal to the main spindle, the apparatus comprising:

a condition input unit that sets an amplitude and a phase of the workpiece;

a vibration computation unit that computes a phase of vibration of a feed shaft on the basis of the input amplitude and phase of the workpiece to generate a feed shaft control signal; and

a feed control unit that controls feed of the feed shaft, wherein

the feed control unit applies forced vibration based on the feed shaft control signal to the workpiece.

6. The machining vibration suppressing apparatus for a machine tool according to claim 5, further comprising:

a tool information input section that acquires a rotational phase of the tool, wherein

the feed shaft control signal output from the vibration computation unit for execution of the forced vibration is a signal that causes vibration at an amplitude set in advance and at a frequency of vibration shifted by a predetermined amount with respect to a rotation speed of the tool.

7. The machining vibration suppressing apparatus for a machine tool according to claim 5, further comprising:

a tool information input section that acquires a rotational phase of the tool, wherein

the feed shaft control signal output from the vibration computation unit for execution of the forced vibration is a signal that causes vibration at an amplitude set in advance and at a frequency of vibration that is equal to a rotation speed of the tool.

8. The machining vibration suppressing apparatus for a machine tool according to claim 6, wherein:

the feed shaft control signal output from the vibration computation unit is a signal obtained by superimposing a control signal that causes first vibration on a control signal that causes second vibration, the first vibration being at a frequency of vibration shifted by a predetermined amount with respect to the rotation speed of the tool and the second vibration being at a frequency of vibration that is equal to the rotation speed of the tool; and

the feed control unit applies forced vibration based on the two types of control signals to the workpiece.