Ceramic Coating Polishing with Robotic Diamond Brush
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for polishing ceramic-coated components in gas turbine engines, such as those used in turbojet engines, are inefficient and costly, often resulting in surface finishes with roughness averages exceeding 150 microinches due to the use of abrasive stone particles in messy slurry baths, which are time-consuming and difficult to clean up.
Innovation Solution
A robotic system using a diamond impregnated brush with a rotary head and force sensing controller is applied to the ceramic-coated components, limiting the force to 5 pounds and removing only 0.0005 to 0.00075 inch of ceramic material, achieving a surface finish of 100 microinches Ra or less in under three minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional abrasive stone particles in water baths are used for polishing ceramic surfaces, then the polishing process can be performed, but the surface finish quality is limited to roughness averages greater than 150 microinches and significant cleanup time is required
Solution Approach 1:
The patent replaces the traditional mechanical vibratory bowl system with liquid slurry with a robotic system using a diamond-impregnated brush. This substitution enables precise control of polishing parameters including force (5-20 ounces), speed (1800-3600 RPM), and path, achieving surface finishes of 100 microinches Ra or less while eliminating the need for messy liquid baths and extensive cleanup operations
Solution Approach 2:
The patent changes multiple parameters simultaneously: uses diamond particles instead of traditional abrasive stones, applies controlled force (5-20 ounces) rather than uncontrolled vibratory motion, operates at specific speeds (1800-3600 RPM), and maintains precise positioning. These parameter changes collectively achieve superior surface finish (100 microinches Ra or less) and reduce processing time to under three minutes per component
2Productivity
If larger abrasive stone particles are used to increase polishing effectiveness, then material removal rate improves, but surface smoothness deteriorates and roughness average increases
Solution Approach 1:
The patent applies different diamond particle sizes in a controlled sequence: coarser diamonds (e.g., 60-120 grit) are used first for rapid material removal, followed by progressively finer diamonds (e.g., 220-400 grit) to achieve the final smooth finish. This staged approach with locally optimized particle sizes at each polishing stage simultaneously achieves high productivity and superior surface smoothness of 100 microinches Ra or less
Solution Approach 2:
The polishing process is segmented into multiple stages, each with specific diamond particle size, force, and duration parameters. This segmentation allows optimization of each stage for its specific function: aggressive material removal in early stages, then progressive refinement in later stages, achieving both high productivity and precision surface finish
3Manufacturing precision
If longer vibratory exposure time is used to achieve smoother surfaces, then surface finish improves, but production time and cost increase significantly
Solution Approach 1:
The patent replaces the time-intensive vibratory bowl process with a robotic brush system that applies controlled abrasive force directly to the surface. This enables achievement of 100 microinches Ra or less surface finish in under three minutes per component, compared to much longer exposure times required by traditional methods, thereby dramatically improving productivity while maintaining or enhancing surface quality
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 method significantly reduces polishing time and costs while achieving a smoother surface finish, improving the reliability and performance of gas turbine engine components by eliminating the need for traditional abrasive particle and water bath processes.
Implementation Method 1
robotically applying a diamond impregnated brush to the exterior surface
Data Source
AI summary
A method of polishing an outer surface of a ceramic coated gas turbine engine component includes applying a rotating diamond brush to the outer surface. The brush is configured to achieve a uniform finish of 150 microinches Ra or less over the surface. The brush contains diamond impregnated bristles, and is affixed to a rotary head of a robotic arm. A force sensing controller limits brush forces against the component. The component disclosed is a hot section turbine vane designed for directional control of high temperature, high-pressure combustion gases, but the method may be applied to other components contained within such aerospace applications. The polished coating provides an improved thermal barrier for maintaining structural integrity of the component in environments having temperatures ranging up to 2,000 degrees Celsius. The method limits abrasive removal of ceramic material to only 0.0005 to 0.00075 inch, and saves time and expense over past practices.