DMLS Surface Post-Processing for Smooth X-Ray Anti-Scatter Grids
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Solution Overview
Problem
Direct metal laser sintering processes using coarse metal powders result in objects with surface roughness and grain attachment that degrade image quality in medical imaging systems due to scattering and inhomogeneous radiation absorption, necessitating improved post-processing for enhanced surface quality.
Innovation Solution
A method and system for treating the surface of objects produced by direct metal laser sintering, involving post-processing technologies like sand blasting, electro polishing, laser polishing, chemical etching, thermal treatment, and high-pressure treatment to reduce surface roughness, ensuring it is smaller than half the grain size on at least 85% of the surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coarse powder with grain sizes of about 20 microns is used for direct metal laser sintering, then productivity is improved and flowability is adequate, but surface roughness increases and image quality performance deteriorates
Solution Approach 1:
The patent applies preliminary surface treatment actions (chemical etching, mechanical polishing, or sandblasting) immediately after the DMLS manufacturing process to remove coarse surface grains before the object is used. This preliminary action eliminates the need to use finer powder in the first place, thus maintaining high productivity while achieving the required surface smoothness for optimal X-ray imaging performance.
2Manufacturing precision
If finer powder is used to improve surface roughness, then surface quality improves, but productivity decreases significantly
Solution Approach 1:
The patent extracts and removes the problematic coarse surface grains from the DMLS-built object through surface treatment processes. By taking out only the surface layer with poor grain structure, the solution achieves smooth surfaces without requiring the entire manufacturing process to use finer powder, thus preserving high productivity while improving surface quality.
3Reliability
If single grains remain on the surface after DMLS, then X-ray scattering and inhomogeneous intensity absorption increase, but removing them requires additional post-processing steps
Solution Approach 1:
The patent changes the surface parameters of the DMLS object by applying treatment processes that modify the surface morphology. Chemical etching changes the chemical composition and surface topology, while mechanical polishing and sandblasting physically alter the surface grain structure. These parameter changes effectively remove or smooth out single grains that cause X-ray scattering, improving image quality without requiring overly complex multi-step procedures.
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 post-processing achieves a smooth surface suitable for medical imaging systems, reducing scattering and enhancing image quality by minimizing grain attachment and uneven topology, thereby improving the performance of X-ray anti-scatter grids.
Implementation Method 1
sand blasting
Implementation Method 2
electro polishing
Implementation Method 3
laser polishing
Implementation Method 4
chemical etching
Implementation Method 5
scanning electron microscopy for evaluation
Data Source
AI summary
The present invention relates to a method and a system for treating a surface of an object obtained by direct metal laser sintering. The object is sintered from a metal powder with a grain size distribution. Due to the manufacturing process, the object can comprise a rough surface with remaining grains of the metal powder attached to the surface. The method according to the present invention provides parameters for post-processing the object to achieve a smooth surface suitable for use in medical imaging systems.