Medical Stent Lattice via Wet-Etched Web Attachment Layer
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Solution Overview
Problem
Existing methods for producing medical stents with self-supporting lattice structures are costly and inefficient due to the use of sacrificial layers, which require complex recycling and additional processing steps, and result in stents with restricted flexibility and edge accuracy issues.
Innovation Solution
A method involving a web attachment layer with a smaller thickness than the web build-up layer, applied directly to the substrate, which forms the lattice structure's ridges, reducing material waste and processing time, and utilizing wet-chemical etching to enhance edge accuracy and flexibility, while eliminating the need for sacrificial layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sacrificial layer is used to achieve high edge accuracy in lattice structures, then manufacturing precision is improved, but device complexity and production time increase due to additional structuring and removal steps
Solution Approach 1:
The patent extracts and eliminates the sacrificial layer from the manufacturing process. Instead of applying a separate sacrificial layer that requires structuring and subsequent removal, the method directly applies a web build-up layer to the substrate, which is then etched away along with the substrate to leave only the desired lattice structure. This removes the complex multi-step process of sacrificial layer application, structuring, and removal.
Solution Approach 2:
The web build-up layer serves multiple functions simultaneously: it provides the material for the lattice webs, acts as the structural element to be etched away, and eliminates the need for a separate sacrificial layer. This multi-functional approach simplifies the overall process while maintaining the ability to achieve high edge accuracy through direct etching of the web material itself.
2Manufacturing precision
If a sacrificial layer is used to achieve high edge accuracy, then manufacturing precision is improved, but production time increases due to additional processing steps
Solution Approach 1:
The patent removes the time-consuming sacrificial layer process entirely. By applying the web build-up layer directly to the substrate and etching both together in a single step, the method eliminates the sequential steps of applying, structuring, and removing a separate sacrificial layer, thereby significantly reducing production time while maintaining edge accuracy.
Solution Approach 2:
The patent merges the sacrificial layer function with the web build-up layer. Instead of having two separate layers (sacrificial and web material), the web build-up layer itself serves as the material to be etched away, combining multiple functions into a single layer and reducing the number of processing steps required.
3Adaptability or versatility
If web dimensions are reduced to improve flexibility, then adaptability is improved, but manufacturing precision deteriorates due to thermal effects in laser cutting
Solution Approach 1:
The patent replaces thermal laser cutting with wet-chemical etching. This substitution eliminates thermal effects that cause unwanted material removal and dimensional inaccuracies. The wet-chemical etching process allows for precise control of web dimensions through chemical reactions rather than thermal melting, enabling the production of smaller, more accurate web structures that maintain high flexibility.
4Adaptability or versatility
If diamond angle is increased to improve flexibility, then adaptability is improved, but force requirements increase for compression
Solution Approach 1:
The patent enables precise control of the diamond angle parameter through direct photolithographic structuring of the web attachment layer and controlled etching. This allows optimization of the diamond angle to achieve the desired flexibility while minimizing compression forces. The ability to precisely control geometric parameters through the direct etching method enables finding the optimal balance between flexibility and force requirements that was not achievable with laser cutting or sacrificial layer methods.
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 reduces production costs and time, increases economic efficiency, and achieves high edge accuracy and flexibility in stents, allowing for improved performance in curved vessels without material deformation or increased force requirements.
Implementation Method 1
The structured first layer is undercut by a wet-chemical etching process acting on the substrate layer
Implementation Method 2
a photoactive layer 4' is also applied to the ridge layer 2'', which forms an etching mask for the wet-chemical etching process after appropriate photolithographic treatment
Implementation Method 3
the stent material is then applied to the composite layer of substrate layer and sacrificial layer in a sputtering process
Data Source
Figure 1
Figure 2a~3
Figure 4~6
AI summary
The invention relates to a method for producing a medical functional element comprising a self-supporting lattice structure which has interconnected webs (2), in which method a first layer is applied to the substrate layer (3), the first layer is structured by means of an etching process, the structured first layer is under-cut by means of a wet chemical etching process acting on the substrate layer (3), the substrate layer (3) is removed in order to form the self-supporting lattice structure, a web constructional layer (2b) is applied to the first layer. The invention is distinguished by the fact that the first layer forms a web attachment layer (2a) which has a smaller layer thickness than the web constructional layer (2b) and is intimately bonded to the web constructional layer (2b) in such a way that the web attachment layer (2a), together with the web constructional layer (2b), forms the webs (2) of the self-supporting lattice structure.