Laser Sintered Orthopedic Implants with Tailored Porosity
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Solution Overview
Problem
Current methods for manufacturing implants, such as femoral implants, are expensive and time-consuming, and lack the ability to create porous structures with varying porosity for tissue integration and bearing surfaces, which are essential for medical applications.
Innovation Solution
A method using selective laser sintering or melting to build a three-dimensional implant structure from a flat substrate, allowing for the creation of porous surfaces with varying porosity by layering metal powders and controlling laser parameters to form predetermined unit cells, which can be bent into shape and finished with additional coatings for articulating surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional casting processes are used to manufacture implants, then the implant structure can be formed, but the production is extremely expensive and time consuming
Solution Approach 1:
The patent applies selective laser sintering parameters (laser power, scan speed, layer thickness) to transform metal powder into solid implant structures. By changing these processing parameters, the system achieves both cost reduction and accelerated production compared to traditional casting methods
Solution Approach 2:
The patent replaces traditional mechanical casting processes with a laser-based additive manufacturing system. This substitution eliminates the need for physical molds and casting equipment, directly building implants layer-by-layer from digital models, thereby reducing both time and cost
2Ease of manufacture
If traditional casting methods are used, then implants can be produced, but each implant requires its own casting device which is destroyed during removal
Solution Approach 1:
The patent replaces complex mechanical casting devices with a laser-based system that builds implants directly from powder. This eliminates the need for physical molds entirely, as the laser selectively fuses powder particles according to digital design data, simplifying the manufacturing process and eliminating device destruction issues
Solution Approach 2:
The patent uses digital 3D models as templates to guide the laser sintering process. The implant is essentially copied from a digital representation, eliminating the need for physical master patterns or molds that would otherwise be required in traditional casting
3Strength
If uniform metal structures are used for implants, then structural integrity is maintained, but tissue integration and bearing surface requirements cannot be simultaneously satisfied
Solution Approach 1:
The patent applies different porosity characteristics to different regions of the implant. The bearing surface is made porous to facilitate tissue integration, while the load-bearing interior maintains higher density for structural strength. This local differentiation is achieved by controlling laser parameters in different build regions
Solution Approach 2:
The patent divides the implant into distinct functional zones with different material properties. The outer shell and load-bearing regions use denser material, while the bone-contact surfaces use porous structures. This segmentation allows each region to be optimized for its specific function
4Strength
If high density metal structures are created through laser sintering, then structural strength is improved, but porous surfaces needed for tissue in-growth are reduced
Solution Approach 1:
The patent creates regions of different density within the same implant structure. By adjusting laser power and scan parameters locally, dense regions provide structural strength while porous regions enable tissue integration. The system maintains precise control over porosity in each zone
Solution Approach 2:
The patent varies laser processing parameters (power, speed, hatch spacing) to control the degree of sintering. Lower energy parameters create porous structures for tissue growth, while higher energy parameters create dense regions for strength, allowing precise porosity control throughout the implant
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 production time and cost while enabling the creation of implants with tailored porosity for tissue integration and mechanical strength, mimicking bone structure, thus improving surgical outcomes.
Implementation Method 1
A method using selective laser sintering or melting to build a three-dimensional implant structure from a flat substrate
Implementation Method 2
The powder is fused, remelted or sintered, by the application of laser energy that is directed in raster-scan fashion
Implementation Method 3
the application of laser energy that is directed in raster-scan fashion to portions of the powder layer
Data Source
AI summary
A method of producing an orthopedic implant including the steps of building a flat open model of at least a portion of an implant. The flat open model may be built using a selective laser center process. The flat open model preferably includes at least one groove along either a first surface or a second surface of the model. Next a force may be applied to the flat open model at predetermined locations to thereby cause the model to bend and assume a shape similar to a desired result. The now bent model may be resurfaced by either applying additional material such that the bent flat open model assumes the shape of a desired implant or the bent open model may be snap fit to an additional element.