Eddy Current Vibration Absorber for Cutting Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cutting tools face issues with vibratory motion during metal cutting operations, leading to poor surface finishes and tool damage, with conventional damping methods like rubber elements and viscous fluids being inadequate for precise stiffness and damping parameter design.
Innovation Solution
An eddy current dynamic absorber assembly is introduced, utilizing a magnetic field and a conductive mass to generate damping through induced currents, allowing for tunable vibration suppression by adjusting the distance between the magnetic material and the conductive absorber mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber elements are used to provide stiffness and damping in a dynamic absorber system, then the system can suppress vibrations, but it is impossible to design the dynamic absorber package to specified stiffness and damping parameters for optimum performance
Solution Approach 1:
The patent applies parameter changes by replacing rubber elements with a magnetic field-based damping mechanism. The damping force is controlled by adjusting parameters such as magnetic field strength, conductor material properties, and the gap distance between the magnet and conductive material. This allows the stiffness and damping parameters to be independently tuned to specified values for optimum performance, resolving the contradiction between vibration suppression reliability and parameter adaptability.
2Reliability
If a viscous fluid is added to the dynamic absorber cavity to increase damping, then damping is increased, but the rubber elements and viscous fluid must be chosen carefully to ensure compatibility or the viscous fluid can deteriorate the rubber elements and alter the performance of the boring bar
Solution Approach 1:
The patent replaces the mechanical/chemical damping system (rubber elements and viscous fluid) with an electromagnetic damping system based on eddy currents. This substitution eliminates the need for viscous fluids and their compatibility considerations with rubber elements. The electromagnetic system provides the required damping capability without the material compatibility issues, reducing device complexity while maintaining reliability.
3Object-affected harmful factors
If metal removal rate is decreased to reduce vibrations, then the amount of vibration is minimally reduced, but this approach interferes with production
Solution Approach 1:
The patent introduces an intermediary dynamic absorber system with optimized stiffness and damping parameters that actively counteracts vibrations during cutting operations. This intermediary system allows the cutting process to maintain high metal removal rates while the absorber system independently manages vibration suppression, thereby resolving the contradiction between reducing harmful vibrations and maintaining productivity.
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 eddy current vibration absorber effectively dampens vibrations, enabling optimized performance by adjusting conductivity, magnetic strength, and distance, providing superior damping capabilities compared to conventional methods.
Implementation Method 1
The relative motion between the magnet and the conductive material causes the conductive material to experience a change in the magnetic flux (i.e. varying magnetic field strength) that is described by Faraday's law of induction, thereby creating a flow of electrons within the conductive material. As the current flows, it creates small loops, which are referred to as eddy currents.
Implementation Method 2
The relative motion between the magnet and the conductive material causes the conductive material to experience a change in the magnetic flux (i.e. varying magnetic field strength) that is described by Faraday's law of induction
Implementation Method 3
The direction of the eddy current obeys Lenz's law, which states that an induced current always flows in the direction opposite to the source that produced the induced current. Due to the direction of rotation of the eddy currents, a magnetic field is produced that is opposite in direction to the relative motion that created them.
Data Source
AI summary
A cutting tool includes a cutting insert mounted to a head attached to a collar at a first end of the cutting tool. A shank is located at a second, opposite end of the cutting tool. A central cavity extends inwardly from the first end toward the shank. An eddy current vibration absorber assembly is disposed within the central cavity. The eddy current vibration absorber assembly includes an absorber mass made of an electrically conductive material, a magnetic material proximate the absorber mass, and a support member for supporting the absorber mass within the central cavity. The eddy current vibration absorber assembly is tuned by selectively adjusting a distance between the absorber mass and the magnetic material.