Okuma Corporation

Nagoya University

Hiroshi Inagaki

Hiroshi Ueno

Eiji Shamoto

Tomoharu Ando

Kiyoshi Yoshino

Norikazu Suzuki

Akihide Hamaguchi

Hajimu Ishii

Toshiya Shikama

Maximum values of actual machining allowances of a workpiece in respective cutting flutes are averaged by control amounts of respective cutting flutes calculated by an arithmetic unit. The arithmetic unit converts the calculated control amounts into an amount in each axis direction and subtracts the value from a feed axis command value in an NC program stored in a storage unit. Then, a numeral value control unit performs machining by controlling respective feed axes based on the subtracted feed axis command value.

Method of controlling feed axes in machine tool, and machine tool performing machining by using the method of controlling feed axes

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.

Machining vibration suppressing method and machining vibration suppressing apparatus for machine tool

A machine tool includes a rotational drive unit that rotationally drives a main spindle to which a tool is attached, a moving unit that relatively moves the tool with respect to the workpiece, and a rotational speed adjustment unit that adjusts a rotational speed of the main spindle by controlling the rotational drive unit. The machine tool also includes a machining start determination unit that determines that machining of the workpiece by the tool is started with the rotational drive unit rotationally driving the main spindle. The rotational speed adjustment unit exponentially raises the rotational speed of the main spindle after reducing the rotational speed to a predetermined rotational speed set in advance, on condition that the machining start determination unit determines that the machining is started, and causes the rotational speed of the main spindle to reach a value of the rotational speed before being reduced.

Machine tool and control method for the same

A vibration suppressing device includes a memory unit storing a stable rotation speed calculated by an arithmetical unit in association with a rotation speed range that includes the stable rotation speed, in which, when a command rotation speed that is a rotation speed of a rotary shaft is inputted in starting machining operation by rotation of the rotary shaft and, the arithmetical unit determines whether the command rotation speed is included in the rotation speed range or not, reads out the stable rotation speed when the command rotation speed is included in the rotation speed range and outputs the stable rotation speed to an NC device instead of the command rotation speed, and starts the machining operation at the stable rotation speed.

Vibration suppressing device

A vibration suppressing device and a vibration suppressing method that are capable of obtaining an accurate optimum rotation speed and shortening a time period from generation of chatter vibration to calculation of the optimum rotation speed are provided. The vibration suppressing device includes: vibration sensors for detecting time-domain vibrational accelerations of a rotary shaft in rotation; and a control device for calculating a chatter frequency and a frequency-domain vibrational acceleration of the rotary shaft at the chatter frequency on the basis of the time-domain vibrational accelerations detected by the vibration sensors, and when the calculated frequency-domain vibrational acceleration exceeds a predetermined threshold value, calculating an optimum rotation speed on the basis of a predetermined parameter, and rotating the rotary shaft at the calculated optimum rotation speed.

Vibration suppressing device and vibration suppressing method for machine tool

The vibration suppressing device includes vibration sensors, a FFT calculating unit, a store device, a calculating unit, and a NC device. The vibration sensors detect a time-domain vibrational acceleration of a rotary shaft during rotating. The FFT calculating unit calculates a frequency of chatter vibration and a frequency-domain vibrational acceleration in the frequency of chatter vibration on the basis of the detected time-domain vibrational acceleration. The store device stores the frequency-domain vibrational acceleration, the frequency of chatter vibration and the like as machining information. When the calculated maximum frequency-domain acceleration exceeds a predetermined threshold value, the calculating unit stores the maximum acceleration, the frequency of chatter vibration, and the like as current machining information in the store device, and calculates an optimal rotation speed of the rotary shaft, by which the chatter vibration can be suppressed, based on the current machining information and previous machining information stored in the store device. The NC device rotates the rotary shaft at the optimal rotation speed.

Method for suppressing vibration and device therefor

A stable rotation speed is acquired by finely changing a rotation speed of a rotary shaftbased on an expected stable rotation speed, and calculating an amount of change of a k' number, and the like. Therefore, a more accurate rotation speed can be acquired, and 'chatter vibration' generated during machining can be suppressed more effectively than a conventional method. As a result, a quality of a workpiece surface can be improved, and a tool wear and the like can be suppressed.

Growing community of inventors

Niwa-gun, Japan

Hiroshi Inagaki