Other

Mitsubishi Denki Kabushiki Kaisha

Mitutoyo Corporation

Yasuda Kogyo Kabushiki Kaisha

Torao Takeshita

Yoshiaki Kakino

Hideo Nakagawa

Makoto Fujishima

Hisashi Otsubo

Yoshinori Yamaoka

Takahiro Hayashida

Tetsuo Nakamura

Yoshio Shinohara

Shigeaki Tokumo

Norikazu Iguchi

Akira Kaneko

A CNC tapping machine includes a spindle to which a tap is attached and a spindle motor for rotating the spindle. The load torque acting on the spindle motor that is detected when performing a tapping procedure without a workpiece is stored in a memory as referential, torque data. During a tapping procedure, a detection device detects the load torque acting on the spindle motor. A computer computes the difference between the load torque defected by the detection device and the referential load torque and uses the difference as the cutting load acting on the tap. As a result, the cutting load torque acting on the tap is accurately detected.

Tapping apparatus and method

A control method for an NC machine tool is provided which ensures a high precision of the contouring control, and allows for extension of the drill life, and reduction in machining time. The control method comprises: generating an operation command signal on the basis of the machining program and a time constant; generating a velocity command signal by multiplying a deviation of a present position signal fed back from the feed drive system ( ) from the generated operation command signal by a position loop gain; generating an electric current command signal by multiplying a deviation of a present velocity signal fed back from the feed drive system ( ) from the generated velocity command signal by a velocity loop gain; and controlling a drive motor of the feed drive system ( ) on the basis of the generated electric current command signal for driving thereof, wherein a machining mode is determined from the machining program and, if the machining mode is a drilling mode, at least one of the operation command signal, the velocity command signal and the electric current command signal is modified when the feed drive system ( ) is driven to be retracted opposite to a drilling feed direction.

Control method for NC machine tool

An abnormality detection apparatus for a tool ( ) is described for judging abnormalities of a tool by a uniformly set threshold value in relation to a cutting load even in a machining process wherein a feed rate changes every moment. The abnormalities of the tool can be judged by the uniformly set threshold value on the basis of the tool load wherefrom the feed load that fluctuates upon the feed rate has been removed.

Abnormality detection apparatus for tool and numerical control apparatus provided with same

A numerical control apparatus ( or ) comprising pecking operation controlling means ( ) which make a feed drive system ( ) retracted when a cutting load detected by cutting load detecting means ( ) exceeds a reference value during a drilling process, the cutting load detecting means ( ) comprise a bite load detecting section ( ) to detect the cutting load at a biting stage wherein a tool bites a work piece, and a stationary load detecting section ( ) to detect the cutting load after the biting stage. The numerical control apparatus ( or ) comprises pecking judgement means ( ) to judge that the feed drive system ( ) should be retracted when a fluctuation load exceeds a specified reference value wherein the fluctuation load is obtained by reducing the bite load from the detected stationary load. When it is judged that the feed drive system ( ) should be retracted, the pecking operation controlling means ( ) make the feed drive system ( ) retracted.

Numerical control apparatus for NC machine tool

A position command method and apparatus for shortening the acceleration and deceleration times of a servo controlled apparatus by effectively utilizing the torque of the controlled apparatus. A value of speed per unit time is developed on the basis of speed and position data, and a constant speed or an acceleration or deceleration function processing may be selectably performed. In the position commanding method and its unit of the present invention, the deceleration stop distance of output speed is computed at all times or is held as a list data as described above and moreover is compared with a residual distance XR. Consequently, the deceleration stop distance does not have to coincide with the residual portion from the acceleration command, and the acceleration/deceleration curve alone can be realized in an independent form. Also, the speed change can be made smoother by correcting the cross point of independently formed acceleration and/or deceleration curves defining a corner section.

Position commanding method and apparatus

A numerical control (NC) device 10 for a machine tool 1 provided with a measurement probe 2b effects measurements of a work 4 on the machine table 5 after a working process. A measurement program, generated by the NC device by modifying a working program, controls the relative movement of the probe 2b with respect to the workpiece 4 such that the probe 2b moves along the contour of the worked portion of the workpiece 4 with a displacement from the neutral position thereof, wherein the displacement of the probe is sampled at a predetermined sampling period. A working error calculation program 17 calculates the working error from the sampled displacements. If the working error is judged correctable, a outside tolerance range and correction re-working is effected so as to reduce the working error. The measurement/re-working cycles are repeated until the working error is within tolerance.

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Tokyo, Japan

Torao Takeshita