Stable Spindle Rotation Number Calculation for Chatter Suppression
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Solution Overview
Problem
Conventional methods for suppressing regenerative chatter vibration in machining require troublesome and skill-dependent operations, such as test machining and impact hammer tests, which are prone to artificial variation and inefficiency.
Innovation Solution
A method and apparatus that calculate a stable spindle rotation number by analyzing vibration data during cutting, detecting regenerative chatter vibration, and adjusting the spindle rotation number to prevent chatter, using a vibration frequency calculator, regenerative chatter detector, spindle rotation controller, and stable rotation number calculator to automatically determine a stable spindle rotation number without prior complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (test machining and impact hammer tests) are used to obtain stability limit diagram data, then the stability limit diagram can be constructed, but the operations are troublesome and prone to artificial variation
Solution Approach 1:
The system uses the machine tool itself to generate vibration data during actual cutting operations, eliminating the need for external impact hammer tests. The control device automatically processes this self-generated data to construct the stability limit diagram, making the system self-sufficient and removing manual intervention requirements.
Solution Approach 2:
The patent replaces the mechanical impact hammer testing method with an automated control device that processes vibration data from the machine tool's own sensors. This substitution eliminates manual striking operations and their associated artificial variations, using automated signal processing instead.
2Reliability
If test machining and impact hammer tests are performed to calculate specific cutting resistance and compliance transfer function, then stable spindle rotation numbers can be determined, but the process is time-consuming and inefficient
Solution Approach 1:
The control device performs preliminary processing of vibration data to construct the stability limit diagram before actual machining begins. By preparing this information in advance using automated calculations from sensor data, the system eliminates time-consuming manual tests during production, improving overall machining efficiency while maintaining reliability.
Solution Approach 2:
The system continuously monitors vibration data during cutting operations and uses this feedback to automatically update and refine the stability limit diagram. This real-time feedback mechanism allows the system to adapt to changing conditions without requiring repeated manual testing, maintaining reliable chatter suppression while improving productivity.
3Measurement precision
If manual impact hammer tests are used to obtain compliance transfer function data, then the stability analysis can be performed, but the results are prone to artificial variation and skill dependency
Solution Approach 1:
The machine tool generates its own vibration data during normal cutting operations, which is then processed by the control device to determine the compliance transfer function. This self-service approach eliminates the need for external impact hammer tests and manual measurements, ensuring consistent results that are not influenced by operator skill or artificial variation.
Solution Approach 2:
The patent replaces the manual mechanical impact hammer testing system with an automated control device that processes vibration signals from the machine tool's own sensors. This substitution ensures that measurements are taken under actual machining conditions and processed automatically, eliminating human error and improving measurement consistency.
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
This approach allows for precise and automatic determination of a stable spindle rotation number, eliminating regenerative chatter vibration without requiring cumbersome pre-operation tests, ensuring stable machining and preventing defective products.
Implementation Method 1
calculating a vibration frequency of the tool by obtaining data on vibration caused by the tool in cutting and analyzing the obtained vibration data
Data Source
AI summary
An apparatus includes vibration data obtainer 30 obtaining data on vibration caused by a tool in cutting, a vibration frequency calculator 22 calculating a vibration frequency of the tool by analyzing the obtained vibration data, a regenerative chatter detector 23 detecting whether regenerative chatter occurs by comparing the calculated vibration frequency of the tool with a spindle rotation number, and a spindle rotation controller 24 gradually decreasing or increasing the spindle rotation number when occurrence of regenerative chatter vibration is detected, and a stable rotation number calculator 25 monitoring variation of the vibration frequency of the tool and determining a spindle rotation number when the variation of the vibration frequency exceeds a predetermined reference value to be a stable rotation number.