Fuel Nozzle Floating Collar Metal Injection Molding
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Solution Overview
Problem
Machined floating collars for gas turbine engine combustors are expensive to manufacture due to the need for anti-rotation features that require costly milling operations and result in significant scrap material.
Innovation Solution
A method involving metal injection molding to create a floating collar with a sacrificial portion that can be sheared off to form a chamfer, eliminating the need for secondary machining and reducing material waste, while using debinding and sintering to achieve the final shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional machining methods are used to manufacture floating collars with anti-rotation features, then the collars can prevent rotation about the fuel nozzle tip, but the manufacturing cost increases and scrap material is generated
Solution Approach 1:
The floating collar is divided into a functional collar portion and a sacrificial portion. The sacrificial portion includes features like a protrusion or tab that extend beyond the collar's outer surface. During assembly, this sacrificial portion engages with a corresponding feature on the fuel nozzle to provide anti-rotation capability, while the collar portion itself remains rotationally free. This segmentation allows the anti-rotation function to be provided by a disposable feature rather than requiring expensive machining of the entire collar.
Solution Approach 2:
The sacrificial portion is designed as a disposable feature that is intentionally allowed to contact and potentially wear or break during operation. This portion is made from the same metal injection molded material as the rest of the collar and requires no additional expensive machining. The sacrificial nature of this portion provides the anti-rotation function at minimal cost compared to traditional machined solutions.
2Reliability
If traditional machining methods are used to create anti-rotation features, then rotation prevention is achieved, but secondary machining operations are required increasing complexity
Solution Approach 1:
The floating collar is divided into a functional collar portion and a sacrificial portion. The sacrificial portion includes features like a protrusion or tab that extend beyond the collar's outer surface. During assembly, this sacrificial portion engages with a corresponding feature on the fuel nozzle to provide anti-rotation capability, while the collar portion itself remains rotationally free. This segmentation allows the anti-rotation function to be provided by a disposable feature rather than requiring expensive machining of the entire collar.
Solution Approach 2:
The invention changes the material state parameter by using metal injection molded material in a substantially dry green condition during the forming operation. The chamfer is formed by applying shear forces to the sacrificial portion while it is still in this softer, more formable state, eliminating the need for subsequent machining operations that would be required if the material were fully sintered or machined traditionally.
3Manufacturing precision
If traditional machining methods are used, then precise features can be produced, but significant scrap material is generated
Solution Approach 1:
The invention changes the material state parameter by using metal injection molded material in a substantially dry green condition during the forming operation. The chamfer is formed by applying shear forces to the sacrificial portion while it is still in this softer, more formable state, eliminating the need for subsequent machining operations that would be required if the material were fully sintered or machined traditionally.
Solution Approach 2:
The sacrificial portion is deliberately extracted or separated from the main collar structure through the chamfer forming operation. This portion is intentionally removed or trimmed away during the manufacturing process, and its material is wasted, but this extraction allows the main collar portion to be produced without expensive secondary machining operations, reducing overall material waste and cost.
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 reduces manufacturing costs and eliminates the need for expensive secondary machining operations, producing a cost-effective, precise floating collar with improved efficiency and reduced material waste.
Implementation Method 1
metal injection moulding a generally cylindrical part having an axis, a collar portion and a sacrificial portion
Implementation Method 2
forming a chamfer at said one end of said collar portion on an inside diameter of the collar portion by applying axially opposed shear forces on opposed sides of the corner to shear off the sacrificial portion from said collar portion along a shearing line extending angularly outwardly from said corner
Implementation Method 3
debinding and sintering the floating collar portion
Data Source
AI summary
A floating collar is metal injected molded with an excess portion intended to be separated, such as by shearing, from the reminder of the molded floating collar to leave a chamfer thereon and/or remove injection marks.