3D Printed Lattice Mirror for High Stiffness
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Solution Overview
Problem
High-cost and complex fabrication processes associated with beryllium alloy mirrors for optical applications, which require expensive tooling and handling of toxic materials, limit their availability and lead times, making it difficult to achieve high stiffness-to-weight performance at a lower cost.
Innovation Solution
3D printing of a lattice structure within a mirror cavity with sacrificial integrated structures, such as tripods, using a powder metal material like AlSi10Mg alloy, to create a high stiffness-to-weight reflective optic, eliminating the need for expensive tooling and allowing for heat treatment and machining to achieve a surface quality of greater than or equal to 64 Root Mean Square (RMS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If beryllium alloy mirrors with machined waffle lightweighting features are used, then high stiffness-to-weight performance is achieved, but manufacturing cost and complexity increase due to expensive tooling and diamond machining requirements
Solution Approach 1:
The patent changes the manufacturing method from conventional diamond machining to additive manufacturing (3D printing), fundamentally altering how the mirror structure is created. This enables complex lattice structures to be built layer-by-layer without expensive tooling, achieving high stiffness-to-weight ratios through digital design and additive fabrication processes
Solution Approach 2:
The patent employs hybrid material approaches by combining aluminum alloys with strategic reinforcement features printed directly into the structure. The lattice structure itself acts as a composite of material distribution optimized for stiffness, replacing the need for exotic beryllium materials while maintaining performance through intelligent structural design
2Strength
If beryllium alloy materials are used, then high specific stiffness is achieved, but handling and processing become hazardous due to toxic material properties
Solution Approach 1:
The patent replaces toxic, long-lived beryllium materials with conventional aluminum alloys that are non-toxic and easier to handle. While aluminum itself is less stiff, the temporary sacrificial support structures enable the aluminum to achieve comparable performance during manufacturing, eliminating hazardous material handling while maintaining final product performance
Solution Approach 2:
The patent fundamentally changes the material selection from beryllium alloy to aluminum alloy, altering the base material properties to eliminate toxicity. This material substitution is compensated for by adding optimized lattice structures and temporary support features during manufacturing, achieving the same functional performance without harmful materials
3Manufacturing precision
If conventional machining processes are used, then high precision mirror surfaces are achieved, but lead times and availability decrease due to complex fabrication requirements
Solution Approach 1:
The patent performs preliminary actions by printing sacrificial support structures and internal lattice features into the mirror blank before final machining. These pre-formed structures provide rigid support during subsequent precision machining operations, enabling faster manufacturing cycles while maintaining high surface quality standards that would otherwise require extensive trial-and-error machining
Solution Approach 2:
The patent changes the manufacturing sequence by reversing traditional approaches: instead of machining a solid blank, the process adds material through 3D printing to create the lattice structure first, then performs minimal finishing operations. This paradigm shift from subtractive to additive-manufacturing-hybrid processes dramatically reduces lead times while preserving optical 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 reduces manufacturing costs while maintaining high stiffness-to-weight performance, enabling the production of reflective optics with a specific stiffness of about 150 E/ρ and Young's modulus of elasticity of about 300 GPa, without compromising image quality, and allows for the use of conventional lower-performance materials like aluminum alloys in high-performance applications.
Implementation Method 1
each the leg comprises an individually frangible segment whereby a top planar surface of each the sacrificial integrated structure is adequately supported by all legs for resisting machining stresses, and each leg is individually severable
Implementation Method 2
the internal mirror cavity comprising a 3-dimensional space-filling volumetric lattice structure
Data Source
AI summary
A 3D-printed reflective optic providing very high specific stiffness through the utilization of a hollow shelled design, with closed back, filled with high-stiffness internal volumetric space-filling open-cell lattice structures. Structurally-integrated sacrificial structures are included for the purposes of reduction or elimination of tooling during post-processing operations.