Porous Structure Scaling for Directional Build Disparities
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Solution Overview
Problem
Rapid manufacturing technologies, such as direct metal fabrication, face directional disparities in building porous structures, leading to inconsistencies in strut thickness and porosity, which can result in structures that are not optimal for biologic ingrowth due to systemic errors in the manufacturing process.
Innovation Solution
A method that involves modifying the features of a structure by assigning a local coordinate system and applying a scaling factor to compensate for directional disparities, allowing features built in one plane to match those in another plane, thereby minimizing distortions and maintaining the original shape and size of the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid manufacturing technology is used to produce porous structures, then manufacturing efficiency is improved, but directional disparities cause inconsistencies in strut thickness and porosity
Solution Approach 1:
The patent applies preliminary action by modifying the digital model before manufacturing to compensate for known directional disparities. The model is pre-adjusted with scaled dimensions in the Z-direction so that when manufactured, the actual dimensions match the intended design specifications, thereby eliminating the need for post-manufacturing correction.
Solution Approach 2:
The patent changes the dimensional parameters of the digital model in the direction perpendicular to the build plane. By applying a scaling factor to the Z-dimension of struts and other features, the model compensates for the systematic under-building that occurs during rapid manufacturing, ensuring consistent strut thickness and porosity across all directions.
2Speed
If rapid manufacturing technology is used to produce porous structures, then manufacturing speed is improved, but structural accuracy deteriorates due to directional disparities
Solution Approach 1:
The patent performs preliminary modification of the digital model to account for directional disparities before the manufacturing process begins. This pre-compensation ensures that the final manufactured structure achieves the desired accuracy without sacrificing manufacturing speed, as no iterative correction is needed.
Solution Approach 2:
The patent replaces physical measurement and correction methods with a computational approach. By using software to automatically scale and modify the digital model based on known disparity patterns, the system maintains high manufacturing speed while achieving improved structural accuracy.
3Ease of manufacture
If conventional porous structures with uniform features are used, then manufacturing simplicity is improved, but structural strength deteriorates due to weak areas at strut intersections
Solution Approach 1:
The patent applies local quality by allowing different parts of the structure to have different properties. Specifically, it modifies the Z-dimension of struts locally based on their orientation and position, while maintaining uniform properties in the X-Y build plane. This targeted approach strengthens critical regions without complicating the overall manufacturing process.
4Device complexity
If features are built in layers perpendicular to the build plane, then manufacturing process simplicity is improved, but dimensional accuracy in the perpendicular direction deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-modifying the digital model to compensate for the layer-by-layer build process effects. The model is scaled in the Z-direction before manufacturing, so that the cumulative effect of layer deposition results in the correct final dimensions, maintaining process simplicity while improving dimensional accuracy.
Solution Approach 2:
The patent changes the dimensional parameters of features in the direction perpendicular to the build plane by applying a scaling factor. This parameter modification compensates for the systematic under-building that occurs during layer-by-layer deposition, ensuring accurate strut thickness and feature dimensions without altering the manufacturing process complexity.
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 approach ensures that porous structures have consistent dimensions across different planes, reducing the risk of structural defects and enhancing their effectiveness for biologic ingrowth by accurately compensating for the directional disparities inherent in the manufacturing process.
Implementation Method 1
DMF techniques produce three-dimensional structures one layer at a time from a powder which is solidified by irradiating a layer of the powder with an energy source such as a laser or an electron beam. The powder is fused, melted or sintered, by the application of the energy source
Implementation Method 2
The powder is fused, melted or sintered, by the application of the energy source such as a laser or an electron beam
Implementation Method 3
fabricating the porous structure according to the model by exposing fusible material to an energy source
Data Source
Figure 1A~2
Figure 3~5B
Figure 6~7
AI summary
The present disclosure allows for more controlled modification of the input data to a Rapid Manufacturing Technologies (RMT) machinery to compensate for systematic error of the manufacturing process, such as directional build discrepancies, by performing the opposite effect to the input data. The modification is achieved with minimal unwanted distortions introduced to other portions of the structure to be built by decoupling the global scaling effects on the whole structure from the desired local effects on certain portions