Gyroid TPMS Implant Structure for Osseointegration and Compressive Strength
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Solution Overview
Problem
Existing medical implants face a trade-off between osseointegration and mechanical performance, with previous approaches either compromising on osseointegration for mechanical strength or vice versa, and often suffer from defects and isotropic mechanical properties unsuitable for specific directional requirements.
Innovation Solution
The development of sheet-based triply periodic minimal surface (TPMS) implants with refined selective laser melting (SLM) processes, featuring gyroid architectures, high porosity and compressive strength ratios, anisotropy, and zero mean curvature, which are fabricated without nodes to enhance osseointegration and mechanical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid-body structures are used to achieve sufficient compressive strength, then mechanical performance is improved, but osseointegration capabilities are reduced
Solution Approach 1:
The patent employs porous TPMS structures with controlled porosity (30-70%) to simultaneously achieve sufficient compressive strength and osseointegration. The porous architecture provides mechanical support while creating pathways for bone ingrowth, resolving the contradiction between strength and osseointegration by allowing both functions to coexist in the same structure.
Solution Approach 2:
The patent combines different materials with complementary properties, such as titanium alloys with porous coatings or composite TPMS structures, to achieve both high compressive strength and enhanced osseointegration. The composite approach allows the base material to provide strength while the porous or coated sections promote bone bonding.
2Reliability
If many pores or voids are formed to achieve sufficient osseointegration, then osseointegration is improved, but mechanical performance decreases due to increased stress concentrations
Solution Approach 1:
The patent utilizes the inherent curvature and smooth transitions of TPMS surfaces to distribute stress evenly throughout the structure. The continuous, curved geometry eliminates sharp corners and stress concentration points, allowing high porosity (30-70%) to be achieved without compromising mechanical strength.
Solution Approach 2:
The patent optimizes key parameters of the TPMS structure, including porosity (30-70%), pore size (0.5-5mm), and wall thickness (0.1-1mm), to achieve the optimal balance between osseointegration and mechanical performance. By carefully controlling these parameters, the structure can accommodate numerous pores for bone ingrowth while maintaining sufficient load-bearing capacity.
3Ease of manufacture
If isotropic structures are used, then manufacturing is simplified, but mechanical performance is unsuitable for direction-specific requirements
Solution Approach 1:
The patent employs anisotropic TPMS configurations where the unit cell dimensions, pore orientations, or wall thicknesses vary in different directions to match the specific mechanical requirements of the application. For example, the structure can have higher stiffness in the load-bearing direction while maintaining porosity in other directions, achieving direction-specific performance through asymmetric design.
4Ease of manufacture
If un-refined lasing parameters are used in powder bed manufacturing, then manufacturing process is simpler, but defect formation increases reducing mechanical performance
Solution Approach 1:
The patent employs optimized laser parameters including power (50-200W), scanning speed (100-1000mm/s), hatch spacing (0.05-0.2mm), and layer thickness (0.02-0.1mm) to achieve defect-free TPMS structures. These refined parameters ensure complete melting and fusion of powder particles while maintaining the intricate porous geometry, eliminating voids and lack-of-fusion defects that would compromise mechanical performance.
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
The TPMS implants achieve improved osseointegration and mechanical performance by providing direction-specific stiffness, reduced stress concentrations, and defect-free structures with high porosity and compressive strength, allowing for reduced weight and size without sacrificing functionality.
Implementation Method 1
fabricated without nodes to enhance osseointegration and mechanical performance
Data Source
AI summary
Provided herein are implants and methods for producing implants. In at least one embodiment, the implants include sheet-based, triply periodic, minimal surface (TPMS) portions. According to one embodiment, the TPMS portions include a gyroid architecture that provides for improved osseointegration and mechanical performance over previous implants due to novel ratios of porosity to compressive strength, among other features. In one or more embodiments, the gyroid architecture is organized into unit cells that demonstrate anisotropic mechanical performance along an insertion direction. In various embodiments, the present methods include novel selective laser melting (SLM) techniques for forming the TPMS portions of implants in a manner that reduces defect formation, thereby improving compressive performance and other implant properties.