Near Net Shape Manufacturing of Complex Components
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Solution Overview
Problem
Current additive manufacturing techniques for producing large structural components from high-strength alloys like titanium are unsuitable due to high costs and the need for post-sintering hot isostatic press processing to eliminate residual porosity.
Innovation Solution
A method involving mixing powdered metals or metal alloys, gravity sintering in a 3D printed sand mold, and subsequent vacuum hot-pressing to produce near net shape components with full density and complex configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If powder bed additive manufacturing is used for high-strength alloy landing gear components, then manufacturing capability is achieved, but post-sintering hot isostatic press processing is required to eliminate residual porosity
Solution Approach 1:
The patent applies preliminary action by performing gravity sintering before the main manufacturing process to pre-densify the powder material. This pre-sintering step consolidates the powder particles and reduces porosity before the component is formed through additive manufacturing, thereby reducing the need for extensive post-processing to eliminate residual porosity.
Solution Approach 2:
The manufacturing process is segmented into distinct stages: gravity sintering of powder in sand molds to create pre-densified green bodies, followed by additive manufacturing of the final component. This segmentation allows each process to be optimized independently, with gravity sintering handling density requirements and additive manufacturing handling geometric complexity.
2Ease of manufacture
If traditional additive manufacturing processes are used for large structural components, then component production is achieved, but costs are high due to post-sintering hot isostatic press processing
Solution Approach 1:
The patent performs preliminary gravity sintering to achieve adequate density before final component formation, eliminating or reducing the need for expensive hot isostatic pressing. The gravity sintering process uses the weight of the powder itself to achieve consolidation, which is far less costly than hot isostatic press equipment and processing.
Solution Approach 2:
The patent uses disposable sand molds for the gravity sintering process, which are inexpensive compared to the expensive hot isostatic press equipment. The sand molds can be easily discarded after use, avoiding the high capital and operational costs associated with maintaining hot isostatic press facilities.
3Manufacturing precision
If sand mold is printed in sections to address powder filling in hard to access areas, then powder filling is improved, but mold assembly complexity increases
Solution Approach 1:
The sand mold is segmented into multiple sections that can be printed separately and assembled. This allows powder to be filled into hard-to-access areas of the mold cavity before the sections are joined together. The segmentation enables complex internal geometries to be accessed during powder filling while maintaining the benefits of additive manufacturing for mold production.
Solution Approach 2:
The modular sand mold sections are designed to nest or fit together like doll houses, with interlocking features that simplify assembly. The sections can be stacked or joined in a systematic way that reduces assembly complexity despite the multi-piece construction, allowing efficient powder filling and subsequent processing.
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 costs by minimizing post-processing requirements and achieves high mechanical strength and density in aerospace-grade components.
Implementation Method 1
raising a temperature of the furnace to a first temperature; and holding the furnace at the first atmosphere and the first temperature for a first predetermined time period to allow for hydrogen (H2) evolution
Implementation Method 2
raising the temperature of the furnace to a second temperature, wherein the second temperature is greater than the first temperature; and holding the furnace at the first atmosphere and the second temperature for a second predetermined time period to allow for homogenization
Implementation Method 3
raising the protective atmosphere to a second atmosphere, wherein the second atmosphere is greater than the first atmosphere; raising the temperature of the furnace to a third temperature, wherein the third temperature is greater than the second temperature and the first temperature; and holding the furnace at the second atmosphere and the third temperature for a third predetermined time period
Implementation Method 4
vacuum hot-pressing the gravity sintered preform to form a near net shape component
Data Source
AI summary
A method for manufacturing near net shapes of complex configuration components. The method includes mixing a plurality of powdered metals to form a blended powder; gravity sintering a sand mold filled with the blended powder to form a gravity sintered preform; and vacuum hot-pressing the gravity sintered preform to form a near net shape component.