Machine Tool Oscillation Control for Chip Breaking Without Resonance
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Solution Overview
Problem
Existing machine tool control devices face the challenge of mechanical resonance due to matching of relative oscillation frequency with the machine tool's resonant frequency, leading to defects in workpiece processing, tool damage, or machine stoppage, which is difficult to prevent without comprehensive checking of varying machining conditions.
Innovation Solution
A machine tool control device that includes a position information acquisition unit, a state determination unit, and an oscillation switching unit to detect and adjust oscillation conditions based on position deviation thresholds, preventing mechanical resonance by changing oscillation parameters when unstable states are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If relative oscillation is applied to break up chips, then chip breaking efficiency is improved, but mechanical resonance may occur causing defects or damage
Solution Approach 1:
The patent implements dynamic adjustment of oscillation parameters (frequency, amplitude, waveform) based on real-time monitoring of position deviation and vibration signals. The control device continuously adapts oscillation conditions during machining to maintain effective chip breaking while avoiding resonance, transforming static oscillation parameters into dynamically adjustable ones responsive to system state
Solution Approach 2:
The system employs feedback control by monitoring position deviation between actual and commanded positions, detecting vibration signals from accelerometers, and using this information to adjust oscillation parameters. When position deviation exceeds thresholds or resonance is detected, the system modifies oscillation frequency or amplitude to eliminate the unstable condition while maintaining chip breaking effectiveness
2Reliability
If oscillation conditions are varied to avoid resonance, then mechanical stability is improved, but chip breaking effectiveness may be reduced
Solution Approach 1:
The patent utilizes periodic oscillation commands superimposed on movement commands to create controlled air cuts that break chips. By varying the period, frequency, and waveform of these periodic oscillations based on detected system state, the system maintains effective chip breaking while avoiding resonant conditions through adaptive periodic action
Solution Approach 2:
The control device changes oscillation parameters (frequency, amplitude, waveform shape) in response to detected resonance conditions or position deviations. This dynamic parameter adjustment allows the system to maintain effective chip breaking by adapting oscillation characteristics to current machining conditions, avoiding fixed parameter limitations
3Reliability
If comprehensive checking of machining conditions is performed to prevent resonance, then reliability is improved, but device complexity increases
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by automatically detecting position deviations, monitoring vibration signals, and autonomously modifying oscillation parameters to avoid resonance. This self-service capability eliminates the need for complex pre-machining resonance analysis and manual parameter optimization, reducing overall system complexity while maintaining high reliability
Data Source
AI summary
The purpose of the present invention is to both break down chips and suppress sympathetic vibration in a machine. This work machine control device superposes a swinging command for commanding relative swinging between a workpiece and a cutting tool onto a movement command for commanding relative movement between the workpiece and the cutting tool, thereby generating air cuts in chips from the workpiece to break down the chips. A position information acquisition unit of the work machine control device acquires position information related to the relative positions of the workpiece and the tool. A state assessment unit of the work machine control device assesses that a state of instability is in effect, under the condition that a positional deviation exceeds a threshold value, the positional deviation increasing with increases in the difference between actual relative positions that are based on the position information and command relative positions that are based on the movement command and the swinging command. A swinging switching unit of the work machine control device performs a switching process for switching a swinging condition in relative swinging, under the condition that it is assessed that the state of instability is in effect.