Bonded Abrasive Tool for Complex Shape Finishing
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Solution Overview
Problem
Current methods for finishing complex shapes in workpieces, such as re-entrant slots in turbine disks, are inefficient due to high tooling costs, slow material removal rates, and limitations in machining difficult-to-machine materials like nickel alloys, particularly in aerospace applications where broaching is expensive and slow.
Innovation Solution
The use of bonded abrasive tools with abrasive grains dispersed in a three-dimensional bonding material, capable of forming complex shapes with a form depth of at least 0.3, allowing for efficient finishing of re-entrant shapes through creep-feed grinding and plunge dressing, enabling high-speed material removal and precise contouring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If broaching is used to finish complex shapes in workpieces, then manufacturing precision is improved, but productivity deteriorates due to slow material removal rates
Solution Approach 1:
The patent changes the fundamental parameters of the finishing process by using creep-feed grinding with a bonded abrasive tool instead of broaching. This allows continuous material removal at higher rates while maintaining precision through the specific grain bonding structure that enables controlled abrasion rather than intermittent cutting
Solution Approach 2:
The patent replaces the mechanical cutting action of broaching blades with an abrasive removal mechanism using a bonded abrasive tool. This substitution enables continuous material removal through abrasion rather than intermittent cutting, significantly increasing material removal rate while maintaining surface quality
2Manufacturing precision
If broaching is used to finish complex shapes, then manufacturing precision is improved, but loss of time increases due to expensive tooling and set-up costs
Solution Approach 1:
The bonded abrasive tool with its complex three-dimensional shape can finish multiple different complex geometries by adjusting grinding parameters rather than requiring different specialized broaching tools for each geometry. This multi-functionality reduces tooling variety and set-up time across different production runs
Solution Approach 2:
The patent creates a negative impression or copy of the desired complex shape in the bonded abrasive tool itself, allowing direct transfer of the precise geometry to the workpiece through abrasion. This eliminates the need for expensive custom broaching tooling while maintaining geometric fidelity
3Ease of operation
If milling is used to machine complex shapes, then ease of operation is improved, but productivity deteriorates due to very slow material removal rates
Solution Approach 1:
The creep-feed grinding process uses continuous abrasive removal rather than intermittent cutting passes. The bonded abrasive tool maintains continuous contact with the workpiece, removing material continuously at a high rate without the tool changes and repositioning required in conventional milling operations
4Ease of manufacture
If conventional abrasive tools are used for finishing, then ease of manufacture is improved, but manufacturing precision deteriorates due to inability to form complex re-entrant shapes
Solution Approach 1:
The patent uses a composite bonded abrasive tool where abrasive grains are embedded in a bonding matrix. This composite structure allows the tool to be formed into complex three-dimensional shapes including re-entrant geometries that conventional solid abrasive tools cannot achieve, while maintaining the abrasive cutting action throughout the tool 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
This approach enables efficient finishing of complex shapes in hard-to-machine materials with reduced tooling costs and increased material removal rates, achieving precise dimensional tolerances and extended tool life while minimizing surface roughness and burn damage.
Implementation Method 1
bonded abrasive tools having particular shapes for finishing of complex shapes within workpieces
Data Source
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AI summary
An abrasive tool includes a bonded abrasive body having abrasive grains contained within a bonding material, wherein the bonded abrasive body comprises a complex shape having a form depth (FD) of at least about 0.3. The form depth is described by the equation [(Rl-Rs)/Rl], wherein Rs is a smallest radius (Rs) at a point along the longitudinal axis of the bonded abrasive body and Rl is a largest radius (Rl) at a point along the longitudinal axis of the bonded abrasive body. The abrasive tool can be used to finish complex shapes in workpieces.