Abstract:
In suppressing chatter vibration of a rotary shaft in a machine tool by fluctuating rotation speed of the rotary shaft, easy setting of a fluctuation parameter is realized. In a monitor apparatus of the machine tool, a graph showing a fluctuation amplitude of the rotation speed is displayed. On this graph, a current fluctuation position (first point) is indicated by a black circle marker, and also, a power limit line L of a motor fluctuation period is depicted based on a predetermined equation. In an area not exceeding the power limit line L, a new fluctuation position (second point) having a larger fluctuation amplitude and a shorter fluctuation period than the current fluctuation position is calculated and indicated with an arrow A guiding this new point from the current fluctuation position.
Abstract:
At least a rotation speed of a rotary shaft and a vibration acceleration in a frequency domain are stored as an operating history, and the operating history is stored not only when the rotation speed of the rotary shaft varies, but also when a maximum value of the vibration acceleration in the frequency domain exceeds a predetermined threshold. Therefore, variation in the rotation speed of the rotary shaft and the chatter vibration occurrence state can be stored in association with each other. Hence, an operator can learn the rotation speed of the rotary shaft and the chatter vibration occurrence state in association with each other. As a result, chatter vibration can be suppressed easily and effectively.
Abstract:
In one embodiment, the disclosed method includes controlling operation of a machine system via actuators and a first set of signals received from sensors, receiving a second signal from a vibration sensor, calculating vibration parameters based on the second signal. The method further includes the steps of normalizing each of the vibration parameters and presenting the normalized vibration parameters in an operator interface. In another embodiment, the system includes a controller configured to receive sensor signals from a machine system and to control operation of the machine system via actuators. The system also includes a condition monitoring user interface configured to display normalized vibration parameters for the machine system.
Abstract:
The subject of this disclosure concerns a screwing equipment comprising at least one rotary member (1), (21); (22), (3) mounted in a tool body (1)) and capable of producing at least one vibrational frequency representing a wear condition of said rotary member(s). The subject of this disclosure is characterized in that it comprises means for measure (5) said vibrational frequencies designed to communicate (1) with means for processing (52) said measurement enabling same to be compared to at least one reference frequency in order to determine said wear condition.
Abstract:
A spindle device for driving a production machine includes a first sensor for detecting a first physical variable of the spindle device, and at least a second sensor for detecting a second physical variable of the spindle device. In this way, it becomes possible to determine the oscillation amplitude of the rotor of a spindle and a temperature profile of a rolling bearing. Monitoring maximum values allows identification of a crash event, whereas the temperature profile allows conclusions as to a need for maintenance. Signal evaluation can take place centrally at the spindle manufacturer's end, thereby allowing needed maintenance works to be planned long term and effectively.
Abstract:
An arrangement for reducing vibrations in a tool holder (4) with a cutting tool (3) and has a vibration sensor on the tool holder (4) that is connected to a guide unit (11). The tool holder (4) has further two piezo-electric actuators 14 and 15. Under the influence of the vibration sensor (9), the guide unit (11) provides an electric alternating current that is actively guided over time so that the actuators movably affect the tool holder (4) to reduce the vibrations in this. To also be able to dampen transients in the tool holder (4) this is movably connected with a passive dampening arrangement that is independent of the guide unit (11) and that is based on the principle of a springing (8) suspended mass (7). The invention also relates to a method for reducing vibrations. The vibrations in the tool holder are sensed and a corresponding signal is provided to a guide unit that over time provides actively guided signals to the actuators. The tool holder is also passively influenced by a dampening arrangement that is independent of the guide unit.
Abstract:
The present invention provides a device for determining the dynamics of a tool sited in a CNC machine, as encapsulated by the Frequency Response Function. The device uses an actively controlled electromagnet to excite forces on the tool. The force is excited in a non-contact manner, allowing the force to be applied to both a stationary and a rotating tool. The displacement is measured by standard means, such as accelerometers, optical displacement or capacitance sensors. The ratio of the force and the displacement in the frequency domain is the Frequency Response Function. The force may be applied as a pure sine wave, providing the Frequency Response Function at the frequency of the sine wave. Varying the frequency of the sine wave provides the Frequency Response Function over the range of frequencies of interest. The control of the force profile is handled entirely by the automated controls and requires no special skills, training or manual interaction by the user. No separate force sensor is required, since the electromagnetic force on the tool may be accurately determined from the design of the electromagnet and the tool position, geometry and material.
Abstract:
A machine for machining workpieces of wood and plastic has a transport path for transporting workpieces through the machine. One or more driven spindles having a tool for machining the workpieces transported through the machine are provided. An adjustable element that is adjustable relative to the tool is provided. At least one data storage is provided for storing data at least of the tool wherein the data are used to determine a position of the adjustable element relative to the tool and are retrievable. In the method for adjusting the machine, characteristic data of the tool are measured and stored in the data storage. The characteristic data are supplied to a control unit. In the control unit positioning data for the adjustable element are calculated based on the characteristic data and then made available for processing the workpieces.
Abstract:
Disclosed is a tunable damping system for use in reducing vibrations associated with metal cutting and tooling. The tunable damping system may be located in a boring bar, an end mill, a modular tool section or the spindle/tool holder of the metal cutting machine. The tunable damping system incorporates a damper mass, elastomeric supports, and a means to lock the mass so as to determine tuning parameters. A tuner assembly consists of sensors and a microprocessor capable of recognizing the most dynamically flexible mode of vibration. The tuner assembly is also capable, through signal processing and microprocessor controlled algorithms, to direct the operator in implementing the proper tuning adjustments of the tunable damping system.
Abstract:
A system for sensing the vibration and lateral force in a cutting tool for the purpose of keeping both these operating parameters within tolerable limits. A piezoelectric crystal is mounted in the chuck supporting the cutting tool. The mechanical stresses on the crystal produce an electrical signal which is then separated into vibration and lateral force components. The negative d.c. analog voltages of these components are summed with a positive d.c. voltage analogous to the programmed feed rate, the algebraic summation resulting in an adaptive control voltage which is used to modulate the spindle power in accordance with the ambient vibration and force.