Rotary Cutting Tool Absorber Assembly for Torsional Vibration Damping
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Solution Overview
Problem
Torsional vibrations in rotating cutting tools, such as drills with helical flutes, lead to undesirable cutting performance, including poor surface finish and tool damage due to self-excited axial oscillations, particularly in large diameter modular drills and tools with high length-to-diameter ratios.
Innovation Solution
A tunable vibration absorber assembly with multiple masses suspended by resilient materials, connected to prevent angular displacement, is integrated into the cutting tool to match the torsional frequency of the drill body, effectively suppressing torsional vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary cutting tool with helical flutes is used for metal cutting, then cutting capability is provided, but torsional vibrations occur leading to poor surface finish and tool damage
Solution Approach 1:
The patent applies the principle of mechanical vibration by introducing a vibration absorber assembly that utilizes tuned mass dampers. These dampers are designed to resonate at the same frequency as the tool's torsional vibration, creating counteracting forces that cancel out the harmful vibrations. The absorber masses are strategically positioned and connected through resilient materials to optimize the damping effect, thereby suppressing torsional vibrations while maintaining cutting capability.
Solution Approach 2:
The patent converts the harmful torsional vibrations into a beneficial effect by using the vibration energy to excite the vibration absorber assembly. The absorber masses, when excited by the tool's torsional vibration, generate counter-vibrations that cancel the harmful effects. This transforms the problematic vibrational energy into a mechanism for vibration suppression, improving surface finish and reducing tool damage.
2Reliability
If absorber masses are suspended by resilient material to suppress vibration, then vibration suppression is achieved, but the structure becomes more complex
Solution Approach 1:
The patent applies the nesting principle by integrating the vibration absorber assembly within the existing tool structure. The absorber masses are positioned inside the tool body, utilizing the available internal space. The resilient materials connecting the absorber masses are configured to fit within the tool's geometric constraints, allowing the vibration suppression mechanism to be embedded without significantly increasing the overall tool complexity or external dimensions.
Solution Approach 2:
The vibration absorber assembly is designed to perform multiple functions: it suppresses torsional vibrations, maintains structural integrity, and can be integrated with the existing tool geometry. The resilient materials serve both as suspension elements for the absorber masses and as structural connectors within the tool body, reducing the need for additional separate components and simplifying the overall structure.
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
Significantly reduces tangential, axial, and radial displacements by damping the torsional mode, improving cutting tool stability and performance.
Implementation Method 1
The tunable absorber masses are suspended by elastomer or other resilient support members
Implementation Method 2
The material properties of the support members, such as stiffness, viscous damping, and the like, are selected in such a way that the torsional frequency of the tunable masses is set close to the torsional frequency of the drill body
Implementation Method 3
the torsional frequency of the tunable masses is set close to the torsional frequency of the drill body
Data Source
AI summary
A rotary cutting tool includes a tool body including a chip flute portion having a plurality of helical chip flutes separated by lobes. In one aspect, a tunable vibration absorber assembly is disposed within a cavity formed in the chip flute portion. In another aspect, the tunable vibration absorber assembly is disposed within a cavity of a replaceable cutting head. In each aspect, the tunable vibration absorber assembly includes one or more tunable absorber masses, a resilient material between the one or more absorber masses and the cavity, and one or more connecting members for preventing relative angular displacement of the one or more tunable absorber masses. The one or more tunable absorber masses are suspended only by the resilient material, thereby enabling the tunable vibration absorber assembly to be tuned to a desired frequency for suppressing torsional vibration of the rotary cutting tool during a cutting operation.