Stent Deburring via Magnetic Abrasive Friction
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Solution Overview
Problem
Existing methods for surface finishing of biodegradable metallic stents, such as electrolytic polishing, result in significant material loss and width reduction, compromising the longevity and effectiveness of the stents due to high weight loss and uneven surface roughness.
Innovation Solution
An automated mechanical deburring apparatus and method using a rotating wheel with magnetic abrasive particles and an automated brush to generate friction on the stent surfaces, effectively removing burrs and smoothing the exterior, interior, and wall surfaces with minimal material removal, ensuring a uniform finish and maintaining biodegradability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrolytic polishing is used for surface finishing, then a smooth and glossy surface is achieved, but high weight loss and large width reduction of stent strut occur
Solution Approach 1:
The patent replaces the electrochemical electrolytic polishing system with a mechanical deburring system consisting of a turning wheel with abrasive surface and an automated brush. This mechanical approach achieves surface finishing through controlled abrasion and friction without the material dissolution inherent in electrolytic processes, thereby reducing weight loss while maintaining surface quality.
Solution Approach 2:
The patent modifies the surface finishing parameters by controlling the friction force, rotational speed, and contact pressure between the turning wheel/brush and the stent. By adjusting these mechanical parameters, the process achieves effective burr removal and surface smoothing with minimal material removal, contrasting with the uncontrolled material loss in electrolytic polishing.
2Manufacturing precision
If electrolytic polishing is used for surface finishing, then a smooth and glossy surface is achieved, but uneven surface roughness and reduced stent longevity occur
Solution Approach 1:
The mechanical deburring system provides more uniform material removal through controlled abrasion compared to electrolytic polishing. The turning wheel with abrasive surface and automated brush create consistent friction across the stent surface, eliminating the uneven roughness that occurs in electrolytic processes and thereby improving surface uniformity and stent reliability.
Solution Approach 2:
The mechanical system uses the stent's own geometry to guide the deburring process. The turning wheel and brush automatically conform to the stent's contours, ensuring uniform contact and consistent surface finishing across complex geometries without the need for additional masking or positioning steps that could create unevenness.
3Loss of substance
If automated mechanical deburring with turning wheel and brush is used, then minimal material loss is achieved, but process complexity increases
Solution Approach 1:
The patent combines the turning wheel with abrasive surface and the automated brush into a single integrated deburring apparatus. Both components operate simultaneously on the stent during rotation, achieving comprehensive surface finishing in one process step. This merging reduces the need for multiple separate operations and simplifies the overall manufacturing process despite the sophisticated functionality of individual components.
Solution Approach 2:
The turning wheel with abrasive surface serves multiple functions: it deburrs the stent surface, smooths rough areas, and controls material removal rate through adjustable friction. The automated brush simultaneously reaches complex geometries and provides consistent contact pressure. This multi-functionality allows a single apparatus to perform what would otherwise require multiple specialized processes, reducing overall system 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
The mechanical deburring process achieves a smooth and polished surface finish with minimal material loss, enhancing the corrosion resistance and coating adherence of the stents, thereby improving their reliability and performance.
Implementation Method 1
The exterior surface of the stent may be deburred by the apparatus by friction produced between the turning wheel and the stent
Implementation Method 2
Interior surface of the stent may be deburred by the apparatus by friction between the stent and the rod
Implementation Method 3
The turning wheel may comprise a magnet inside. The automated method may further comprise applying magnetic abrasive particles to the turning wheel
Data Source
AI summary
An apparatus and method is provided for finishing surfaces and edges of a stent. The apparatus may be capable of rotating a turning wheel, lowering the turning wheel onto a stent, tilting the stent, and polishing and deburring exterior, interior, and wall surfaces of the stent. An automated method is provided for polishing and deburring exterior, interior, and wall surfaces of a stent. Additionally, the automated method may include rotating a turning wheel, applying magnetic abrasive particles to the turning wheel, lowering the turning wheel onto the stent, tilting the stent, and polishing and deburring the exterior, interior, and wall surfaces of the stent.