Stent Inner-Diameter Micropattern Transfer by Electrochemical Micromachining
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Solution Overview
Problem
Existing methods for fabricating micro-sized features on the inner diameter of stents, such as direct laser ablation, metal stamping/pressing, and photolithography/wet etching, are inadequate for achieving micro-sized features on stent surfaces effectively.
Innovation Solution
The method involves electrochemical micromachining using a customized electrode with a non-conducting mask to pattern and transfer micro-sized features onto the inner diameter of stents through a through-mask electrochemical micro-machining process, allowing for precise machining of micro-patterns on the stent surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct laser ablation is used to fabricate micro-sized features on stent inner diameter, then micro-patterns can be created, but the process is time-consuming and lacks precision for mass production
Solution Approach 1:
The patent uses a patterned cathode electrode as a template or copy that transfers its micro-pattern geometry to the anode stent surface through electrochemical machining. The cathode's patterned structure serves as a reusable master that can be replicated across multiple stents, enabling precise mass production of micro-patterns without time-consuming individual laser ablation of each stent.
Solution Approach 2:
The patent replaces the mechanical laser ablation process with an electrochemical machining process. Instead of using mechanical laser energy to remove material point-by-point, the system uses electrochemical reactions between the patterned cathode and anode in an electrolyte solution to transfer the micro-pattern, significantly improving production efficiency while maintaining precision.
2Productivity
If metal stamping/pressing is used to create micro-sized features, then manufacturing speed increases, but precision and surface quality deteriorate
Solution Approach 1:
The patent replaces mechanical stamping/pressing with electrochemical machining. Instead of using mechanical force to deform or remove material, the system uses controlled electrochemical dissolution at the anode surface where the cathode pattern contacts it. This substitution maintains high production speed while achieving superior micro-pattern precision and surface quality without mechanical deformation.
Solution Approach 2:
The patent changes the fundamental processing parameter from mechanical stress (in stamping) to electrochemical potential and current density. By controlling electrical parameters such as voltage, current, and electrolyte composition, the system achieves precise micro-pattern transfer with clean surfaces, avoiding the precision loss and surface damage inherent in mechanical pressing methods.
3Manufacturing precision
If photolithography/wet etching is employed for micro-pattern fabrication, then precision improves, but device complexity and process steps increase
Solution Approach 1:
The patent combines the pattern transfer and micro-pattern fabrication steps into a single electrochemical machining operation. Instead of separate photolithography coating, patterning, and wet etching steps, the system integrates pattern definition (on the cathode) and pattern transfer (to the anode) into one concurrent electrochemical process, reducing overall process complexity while maintaining precision.
Solution Approach 2:
The patent uses a pre-patterned cathode electrode as a reusable template that directly transfers its pattern to the anode. This copying approach eliminates the need for complex photolithography steps on each workpiece, as the pattern is already defined on the cathode and simply replicated through electrochemical dissolution, simplifying the overall manufacturing process.
4Productivity
If conventional ECM is used for stent machining, then material removal is achieved, but micro-sized feature precision and surface quality are insufficient
Solution Approach 1:
The patent transitions from conventional 3D ECM to 2D surface micro-pattern transfer by using a planar patterned cathode electrode. This dimensional change allows precise control of current distribution across the stent surface, enabling micro-sized feature creation with high precision while maintaining efficient material removal through the electrochemical dissolution process.
Solution Approach 2:
The patent introduces a patterned cathode electrode as an intermediary between the power source and the stent anode. This intermediary controls and directs the electrochemical reactions to occur only at specific locations corresponding to the cathode pattern, enabling precise micro-feature creation while the bulk electrochemical process maintains high material removal efficiency.
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 enables efficient and precise transfer of micro-patterns onto the stent's inner diameter, enhancing endothelial cell migration and integration, thereby improving the stent's performance in vascular applications by promoting rapid endothelialization and reducing thrombus deposition.
Implementation Method 1
transferring the desired features to the medical device anode by electrochemical micromachining
Data Source
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Figure 8A~8B
AI summary
This invention is directed to a new method of mass-transfer/fabrication of micro-sized features/structures onto the inner diameter (ID) surface of a stent. This new approach is provided by technique of through mask electrical micro-machining. One embodiment discloses an application of electrical micro-machining to the ID of a stent using a customized electrode configured specifically for machining micro-sized features/structures.