A display control device includes a calculation unit for calculating a first rotating speed on the basis of a vibration level detected by a vibration detection unit when the vibration level has exceeded a predetermined value, a change receiving unit for receiving a change instruction for changing a second rotating speed that is a rotating speed when the vibration level has exceeded the predetermined value to the first rotating speed, and a display control unit for performing control to display, on an operation screen, the first rotating speed, the second rotating speed, and a ratio display unit indicating a change ratio to a third rotating speed specified by a machining program, and performing control to display the first rotating speed at a position in the ratio display unit corresponding to a change ratio of the first rotating speed to the third rotating speed.

A machining status display apparatus includes a display device having a display screen, a stability lobe picture creator creating, based on specifications of a tool to be used, display picture data for displaying a stability lobe as a correlation diagram between a spindle rotation speed and a limit depth of cut of the tool above which regenerative chatter occurs, a first machining information picture creator creating display picture data for displaying machining related information other than regenerative chatter corresponding to set machining conditions, and a display controller displaying the stability lobe and the machining related information with the stability lobe and the machining related information superimposed one on another on the display screen of the display device based on the display picture data created by the stability lobe picture creator and the display picture data created by the first machining information picture creator.

A rotation controller controls a rotation mechanism for rotation of a spindle. A movement controller causes, while the spindle is rotating, a feed mechanism to bring a cutting tool into contact with a workpiece to cause the cutting tool to cut the workpiece. The rotation controller controls a spindle rotation speed so as to accelerate or decelerate the rotation of the spindle, and the movement controller brings the cutting tool into contact with the workpiece after the rotation controller starts the rotation of the spindle, and separates the cutting tool from the workpiece while the spindle rotation speed is put under the acceleration control or deceleration control exercised by the rotation controller.

A method and a device for determining a rotational slippage of a tool that is frictionally held in a tool holder. The rotational slippage of the tool is determined by evaluating a phase and/or a period length of a periodic process signal from the tool.

A diagnostic device includes: a spindle rotational frequency acquisition unit configured to acquire a spindle rotational frequency of a spindle; a pitch acquisition unit configured to acquire a pitch of streaks generated on a surface of a workpiece; a feed rate acquisition unit configured to acquire a feed rate of a tool when mirror surface machining is performed on the surface of the workpiece; a streak frequency calculator configured to calculate a streak frequency that is a cause of the streaks, from the pitch of the streaks and the feed rate of the tool; a causal frequency calculator configured to calculate a causal frequency which causes vibrations of the streak frequency; and a notifying unit configured to indicate whether or not there is a peripheral device that generates vibrations at the causal frequency, around a machine tool.

The feed axis device of a machine tool is equipped with first and second planetary gear speed reducers, each of which is obtained from an inner element, outer element, and intermediate elements that are disposed between the two, the elements being disposed so as to be mutually rotatable and combined in series so that one of the three elements is a fixed section, one of the two remaining elements is the input section and the other is the output section. The element that is the input section of the first speed reducer and the element that is the input section of the second speed reducer are connected to a single drive source. The element that is the output section of the first speed reducer and the element that is the output section of the second speed reducer are connected. The feed axis device is provided with an actuator.

A machine tool includes a tool and a workpiece machined by the tool, and sensors configured to detect a position of the tool and/or the tool holder holding the tool in a spatially and time resolved manner A method for offline and/or online identification of a state of the machine tool includes: a) detecting or providing positions p.sub.i of the tool and/or of the tool holder at a series of points in time i, i=1 . . . n; b) determining for the series of points in time i a series of position changes ?m.sub.i according to the formula ?m.sub.i=p.sub.i/p.sub.i-1 and a series of speed changes ?v.sub.i according to the formula ?v.sub.i=v.sub.i/v.sub.i-1 with $v_i=\frac{P_i-P_{i-1}}{t_i-t_{i-1}}$
and formula $v_{i-1}=\frac{P_{i-1}-P_{i-2}}{t_{i-1}-t_{i-2}};$
c) identifying the state of the tool, the tool holder, the machine tool and/or the workpiece machined in the machine tool based on the position changes ?m.sub.i and the speed changes ?v.sub.i.

A spindle speed adjusting device in machining is provided, which may include a plurality of signal detection modules, a signal capturing module and a signal processing module. Each of the signal detection modules may keep measuring the vibration signals in machining. The signal capturing module may capture the vibration signals. The signal processing module may execute a transmissibility analysis to obtain the transmissibility between the signal detection modules, and execute a frequency response fitting according to the transmissibility to obtain a plurality of system dynamic parameters, and then execute a stability lobe diagram analysis to calculate the optimized spindle speed of the machining tool so as to make the machining tool operate at the optimized spindle speed. The signal processing module may repeatedly execute the transmissibility analysis, the frequency response fitting and the stability lobe diagram analysis to keep updating the optimized spindle speed until the machining process ends.

A chatter database system, which includes a central chatter database, which is fed with data corresponding to the machining and chatter conditions of machining tools, particularly a milling, turning, drilling or boring machine. The data fed to the central chatter database is obtained and collected from at least two individual machining tools included in the chatter database system. The data is sent to the central chatter database via a data connection, preferably via a secured network, to generate chatter stability maps based on real encountered conditions.

A system, method and computer-readable medium for fine-tuning speed selection for reducing machine chatter. The system includes circuitry configured to determine a predetermined speed of the machine. The circuitry identifies a stability lobe based on the predetermined speed of the machine and selects a first set of fine-tuning speeds from a range of machine speeds corresponding to the determined stability lobe. Further, the circuitry causes the machine to operate at one or more of the first set of fine-tuning speeds.