Spindle Vibration Control via Piezoelectric Feedback
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Solution Overview
Problem
Machine tools, particularly high-frequency milling machines, face accuracy issues due to unwanted vibrations in the rotating spindle caused by factors like imbalance, cutting forces, and resonance, which existing technologies have not adequately addressed.
Innovation Solution
A device with measuring devices such as non-contacting position transducers, acceleration pick-ups, and strain gauges around the spindle, coupled with a control unit that processes data to calculate correction values for piezoelectric or electrorheological correction devices to reduce vibrations in real-time, ensuring optimal machining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed rotation is used to increase productivity, then productivity is improved, but vibrations increase and manufacturing precision deteriorates
Solution Approach 1:
The patent implements a feedback control system where measuring devices (acceleration sensors, position transducers) continuously monitor spindle vibrations and feed this information to a control unit. The control unit processes the vibration signals and generates correction commands to actuators that actively counteract the detected vibrations, creating a closed-loop feedback system that maintains precision at high speeds
Solution Approach 2:
The patent employs dynamic vibration compensation through actuators (piezoelectric elements, electromagnetic actuators) that can rapidly adjust their output in real-time based on measured vibration conditions. This dynamic response allows the system to adapt to changing vibration patterns during high-speed operation, maintaining manufacturing precision despite increased productivity
2Manufacturing precision
If vibration measurement and correction systems are added to reduce vibrations, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into unified components: the control unit performs both signal processing and correction command generation; the actuators serve both as measurement platforms and correction mechanisms; the measuring devices provide both diagnostic and control feedback. This multi-functionality reduces the number of separate components needed, managing system complexity while achieving vibration reduction
Solution Approach 2:
The patent introduces a control unit as an intermediary that processes vibration measurements and translates them into correction commands. This intermediary layer simplifies the overall system architecture by centralizing the control logic and providing a clear interface between the measurement and correction subsystems, making the complex vibration reduction process more manageable
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces unwanted spindle vibrations, maintaining machining accuracy by monitoring and correcting for thermal effects, overloads, and process parameters, resulting in improved tool performance and workpiece precision.
Implementation Method 1
a triaxially measuring acceleration sensor can be inserted in the spindle as an acceleration pick-up. Such a three-dimensional acceleration is a triaxially measuring acceleration sensor for measuring oscillations and vibrations, having a voltage output. The acceleration sensor measures simultaneously the three spatial components x, y, z of the acting acceleration.
Implementation Method 2
At least one piezoelectric element and/or electrorheological devices can be provided as correction devices.
Implementation Method 3
At least one piezoelectric element and/or electrorheological devices can be provided as correction devices.
Data Source
AI summary
A device and a method for preventing vibrations (19) in a rotating spindle (1) mounted in at least one front 8 and one rear bearing (9) in a machine tool, wherein the device comprises measuring units (2, 3, 4, 5) for detecting the vibrations (19) and correction device (6) for preventing the vibrations (19) disposed directly about the periphery (10, 11) of the spindle (1) in a contacting or non-contacting manner and that a control unit (7) for processing the measuring units (2, 3, 4, 5) and for calculating the correction values for the correction device (6) is assigned to this device.