Custom Prosthetic Limb with Additive Manufacturing
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Solution Overview
Problem
Existing prosthetic limbs are not readily available and are unaffordable for individuals in remote areas, leading to inadequate mobility solutions, with lower-quality prosthetics often featuring basic hinges that do not lock out during strides, increasing the risk of falls.
Innovation Solution
A custom-designed prosthetic limb created using computer-aided design (CAD) software and computer-controlled fabrication processes, matching the mechanical dimensions of the user's intact limb, featuring a movable ankle with a ball joint, flexible rear member, and a locking mechanism for stability, fabricated using rapid prototyping techniques like 3D printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If basic hinge mechanisms are used in prosthetic limbs, then manufacturing cost is reduced, but reliability and stability deteriorate due to inability to lock out during strides
Solution Approach 1:
The prosthetic leg is divided into multiple independent components (socket, pylon, knee mechanism, ankle mechanism, foot) that can be manufactured separately using additive manufacturing and then assembled. This segmentation allows for cost-effective production while maintaining reliability through proper modular design of each component.
Solution Approach 2:
The patent changes the manufacturing parameters from traditional subtractive or formative methods to additive manufacturing parameters, enabling complex locking mechanisms and joint structures to be produced cost-effectively. This parameter change allows intricate stability features to be integrated without significantly increasing manufacturing cost.
2Reliability
If custom-designed prosthetic limbs with advanced mechanisms are manufactured, then reliability and functionality are improved, but manufacturing cost increases making them unaffordable
Solution Approach 1:
The prosthetic mechanisms are designed to be self-regulating and self-adjusting without requiring external power sources or complex control systems. The knee and ankle mechanisms automatically lock and unlock based on gravitational forces and user movement, eliminating the need for expensive motors, sensors, and control electronics while maintaining high functionality.
Solution Approach 2:
The patent employs additive manufacturing to produce prosthetic components at low cost, making the entire prosthetic leg economically viable as a disposable or periodically replaceable device rather than a permanent investment. This approach makes advanced functionality accessible to users with limited financial resources.
3Productivity
If traditional manufacturing processes are used, then production capacity is maintained, but adaptability and customization capability deteriorate
Solution Approach 1:
Standardized component designs and assembly procedures are prepared in advance through additive manufacturing process development. This preliminary action enables rapid production of customized prosthetics without sacrificing production capacity, as the manufacturing system is pre-configured for efficient fabrication of custom geometries.
Solution Approach 2:
The manufacturing approach changes from fixed mold-based production to parameter-driven additive manufacturing, where each prosthetic can be customized by modifying digital design parameters while maintaining efficient production throughput. This allows high adaptability without reducing productivity.
4Reliability
If prosthetic limbs are made with complex locking mechanisms, then stability is improved, but device complexity increases
Solution Approach 1:
The complex locking mechanisms are extracted from traditional multi-component mechanical assemblies and reimagined as integrated lattice structures fabricated directly through additive manufacturing. This extraction simplifies the overall device complexity by eliminating the need for separate springs, cam followers, and adjustment mechanisms while maintaining stability functionality.
Solution Approach 2:
The prosthetic components utilize composite lattice structures that combine multiple material properties within a single monolithic structure. These composite designs provide both the structural strength needed for locking mechanisms and the flexibility for movement, reducing overall mechanical complexity while enhancing stability.
Data Source
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AI summary
A prosthetic limb has an outer surface that is a mirror image of an intact limb or a generic limb design. The intact limb is scanned and the surface data is manipulated to create a virtual mirror image. If generic data is used, the intact leg can be measured and the generic surface can be adjusted so the prosthetic limb appears similar to the intact limb. The end of the amputated limb is also measured to obtain socket data. A knee and foot are incorporated to form a virtual prosthetic limb represented by design data. The design data for the virtual prosthetic limb is forwarded to a rapid prototyping machine that fabricates the entire leg simultaneously. Once completed, the prosthetic limb is shipped to the patient.