Okuma Corporation

Takumi Hongo

Hiroshi Ueno

Tomoharu Ando

Takashi Norihisa

Mariko Ito

Hitoshi Sumi

A feed axis monitoring device includes a position deviation calculating unit, a machined surface perpendicular direction calculating unit, a position deviation component converting unit, a threshold value calculating unit, and an abnormality determining unit. The position deviation calculating unit calculates a position deviation of the feed axis. The machined surface perpendicular direction calculating unit calculates a direction perpendicular to a machined surface at a time of a position deviation calculation. The position deviation component converting unit converts a position deviation of the feed axis into a component in the perpendicular direction. The threshold value calculating unit calculates a threshold value based on a preset relation between an operating state of the main spindle and the threshold value. The abnormality determining unit determines that the feed axis has an abnormality when the position deviation exceeds the threshold value.

Feed axis monitoring device and monitoring method for machine tool

A main spindle monitoring device determines an abnormality of a main spindle in a machine tool. The main spindle monitoring device includes a main spindle operation monitoring unit and a feed axis operation monitoring unit. The main spindle operation monitoring unit monitors a change of an operation condition of the main spindle based on a main spindle load. The feed axis operation monitoring unit monitors a change of an operation condition of a feed axis based on a feed axis load. The abnormality of the main spindle is determined when the main spindle operation monitoring unit detects the change of the operation condition of the main spindle and the feed axis operation monitoring unit does not detect the change of the operation condition of the feed axis in a state where a constant rotation speed is commanded to the main spindle while the feed axis is driving.

Main spindle monitoring device and main spindle monitoring method of machine tool

An abnormality diagnostic device for a feed axis mechanism diagnoses an abnormality occurrence and an abnormal portion of the feed axis mechanism. The feed axis mechanism transmits a rotation of a motor to a ball screw coupled by a coupling to rotate the ball screw. The abnormality diagnostic device includes a resonance frequency measuring unit and a diagnosis unit. The resonance frequency measuring unit measures a resonance frequency at a plurality of stroke positions within a stroke range of the feed axis mechanism. The diagnosis unit identifies the abnormal portion based on a relationship between the stroke positions and change amounts relative to a standard value of the measured respective resonance frequencies.

Abnormality diagnostic device for feed axis mechanism

A feed axis diagnostic device for a machine tool is provided. The machine tool machines a workpiece while driving a moving body with feed axes along a guide surface of a rolling guide mechanism. The feed axis diagnostic device includes a feed axis diagnostic unit configured to detect an abnormality in the rolling guide mechanism in the machine tool. The feed axis diagnostic unit is configured to acquire a feed speed during non-machining and a load applied to the feed axes at the feed speed. The abnormality is detected based on an approximate function calculated from relationships between a plurality of the feed speeds and a plurality of the loads acquired under a plurality of different feed speed conditions in a predetermined period.

Feed axis diagnostic device and diagnostic method for machine tool

An abnormality diagnostic method for a feed axis device that diagnoses an abnormality of the feed axis device including a screw shaft and a nut, the feed axis device being incorporated in mechanical equipment, the abnormality diagnostic method includes controlling an operation of the feed axis device such that the screw shaft operates in a predetermined operating pattern, detecting a physical quantity signal generated from the feed axis device, and performing an abnormality diagnosis for the feed axis device based on the physical quantity signal detected by the detecting in accordance with a predetermined abnormality diagnosis algorithm. The performing includes performing a frequency analysis on the physical quantity signal to extract respective frequencies corresponding to a plurality of operating positions in the operating pattern and performing the abnormality diagnosis based on change of the frequencies corresponding to the respective operating positions.

Abnormality diagnostic method and abnormality diagnostic device for feed axis device

A diagnostic device diagnoses a state of a test object. The diagnostic device includes a physical model base diagnosis unit, a mathematical model base diagnosis unit, a model update necessity determination unit, and an update notification unit. The physical model base diagnosis unit is configured to perform the diagnosis using a feature quantity. The mathematical model base diagnosis unit is configured to perform the diagnosis using a machine learning model. The model update necessity determination unit is configured such that if diagnostic results by the physical model base diagnosis unit and the mathematical model base diagnosis unit differ, the model update necessity determination unit determines that at least one of a physical model or a mathematical model is necessary to be updated. The update notification unit is configured such that if the model update necessity determination unit determines that the update is necessary, the update notification unit notifies it.

Diagnostic device using both a physical model and mathematical model for anomaly detection

An operating state display device displays an operating state of a feed axis in a machine tool including the feed axis. The feed axis linearly moves a moving body via a ball screw with a servomotor. The operating state display device includes a passage number count unit, a use frequency calculation unit, and a display unit. The passage number count unit preliminarily divides an operating range of an axis operation of the feed axis into a predetermined number of sections and counts passage numbers of the moving body in the respective sections. The use frequency calculation unit calculates frequencies of use in respective classified types of the axis operation in each of the sections based on the counted passage numbers. The display unit displays the calculated frequencies of use in the respective classified types on a monitor in a predetermined aspect.

Operating state display device and operating state display method for feed axis in machine tool

It is an object to perform an abnormality diagnosis for a feed axis without additionally adding a sensor or the like. A frequency characteristic of a feed axis and a damage frequency that occurs when the feed axis that has been damaged performs an axis operation are obtained, a frequency where a gain is maximized in the obtained frequency characteristic is calculated, and a feed velocity where the frequency matches the damage frequency is calculated. An axis operation is performed on the feed axis with the calculated feed velocity, and a frequency analysis is performed on servo information regarding a control of a servo motor during the axis operation. Then, the presence and absence of a peak of the damage frequency is confirmed from a result of the frequency analysis, and when the peak is present, it is determined that it is abnormal.

Abnormality diagnostic method for feed axis and abnormality diagnostic device for the same

An abnormality diagnostic method executes causing the feed axis to perform an axis operation in a predetermined diagnosis condition to obtain servo information according to a control of the servomotor, performing a frequency analysis on the obtained servo information, obtaining a damage frequency generated while the feed axis whose bearing is damaged performs the axis operation, from a result of the frequency analysis, and comparing the obtained damage frequency with a predetermined threshold to determine a presence/absence of an abnormality. In the determining, before the damage frequency is compared with the threshold, a determination whether a vibration frequency of the bearing interferes with a vibration frequency generated while a rolling element passes through a nut of the ball screw or not is performed, and the comparison is performed by setting the respective thresholds that are different in a case of the interference and a case of no interference.

Abnormality diagnostic method and abnormality diagnostic device for feed axis

A diagnostic result display method in a diagnostic device calculates a diagnostic result by a determination of a predetermined state and a certainty factor of the determination. The diagnostic result display method includes setting preset predetermined colors to predetermined states, setting a preset area of a geometric shape according to certainty factors, and displaying the area of the geometric shape in at least one of the predetermined colors.

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Niwa-gun, Japan

Takumi Hongo