Oscillating Tool Machining to Reduce Thrust Force and Wear
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Solution Overview
Problem
Machining operations, such as drilling, face challenges in balancing speed and force to prevent tool wear and maintain geometry integrity, as rapid machining increases thrust force and torque, potentially shortening tool life and affecting workpiece quality.
Innovation Solution
A method involving linear movement of a tool along a feed axis with superimposed oscillation and rotation, where the optimal oscillation frequency is determined to minimize force applied during machining, allowing for faster feed velocities while controlling thrust force within predefined limits, and adapting to non-homogenous zones by modifying oscillation frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If machining operations are performed quickly to increase productivity, then productivity is improved, but thrust force and torque increase which shortens tool life and affects workpiece quality
Solution Approach 1:
The patent applies ultrasonic vibration to the cutting tool at high frequency (20-100 kHz) to create oscillating motion that reduces the average cutting force and torque during machining. This vibration mechanism allows faster feed rates while maintaining acceptable thrust force levels, thereby increasing productivity without compromising tool life or workpiece quality
2Productivity
If machining operations are performed quickly to increase productivity, then productivity is improved, but thrust force and torque increase which affects the geometry and integrity of the feature desired on the workpiece
Solution Approach 1:
The ultrasonic vibration of the cutting tool creates a separating effect between the tool and workpiece during machining, reducing friction and heat generation. This allows faster machining speeds while maintaining precise dimensional control and feature geometry integrity, as the vibration prevents tool rubbing and ensures clean cutting action
3Force
If oscillation is superimposed at multiple frequencies during optimization mode, then optimal oscillation frequency is determined to minimize force, but device complexity and process time increase
Solution Approach 1:
The patent implements an optimization mode that performs preliminary frequency sweep tests before actual machining operations. During this preliminary phase, multiple oscillation frequencies are tested to identify the optimal frequency that minimizes thrust force for the specific workpiece material and geometry. This preliminary action stores the optimal parameters for subsequent machining, reducing the need for complex real-time control while achieving minimal force application
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 reduces tool wear, enables faster machining without compromising workpiece quality, and enhances the efficiency and precision of machining operations by optimizing oscillation frequencies and rotational velocities.
Implementation Method 1
providing linear movement of a tool along a feed axis relative to a workpiece
Implementation Method 2
superimposing oscillation of the tool onto the feed axis
Data Source
AI summary
An example method includes performing a machining operation by providing linear movement of a tool along a feed axis relative to a workpiece while superimposing oscillation of the tool onto the feed axis and providing rotation of the tool relative to the workpiece. During an optimization mode, the machining operation is performed on a first workpiece portion while providing the linear movement at an initial feed velocity, and sequentially superimposing the oscillating at a plurality of different frequencies. An optimal oscillation frequency is determined from the plurality of different frequencies which causes the tool to apply less force to the first workpiece portion at the initial feed velocity than others of the frequencies. During a run mode, the machining operation is performed on a second workpiece portion having a same composition as the first workpiece portion while superimposing the oscillation at the optimal oscillation frequency.