Additive Manufacturing Stent Connectors with Selective Ductility

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Solution Overview

Problem

Existing methods for manufacturing stents using additive manufacturing face challenges in creating shapes where connectors need to be easily removable without affecting the remaining device, often requiring material changes or complex removal processes.

Innovation Solution

The method involves forming connectors that are more brittle than the rest of the stent using incomplete fusion, material selection for intermetallics or ceramics, or hydrogen exposure, allowing for mechanical removal without damaging the stent components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If connectors are formed between crowns of adjacent bands using additive manufacturing, then structural support is provided for the following layer of material, but the connectors cannot be easily removed without affecting the stent components

Engineering Contradiction:

Improveease of connector removalVSAvoidintegrity of stent components

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by creating connectors with different material properties than the main stent body. Specifically, the connectors are formed with a different alloy composition (e.g., different nickel content in Nitinol) that gives them distinct ductility characteristics, allowing selective removal without damaging the stent structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by varying the material composition parameters of the connectors compared to the main stent body. By adjusting alloying elements and heat treatment parameters, the connectors achieve different mechanical properties (particularly ductility) that enable selective removal while maintaining stent integrity.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If different materials are used for connectors configured to be removed versus connectors configured to remain, then selective removal is enabled, but the additive manufacturing process is complicated

Engineering Contradiction:

Improveselective connector removalVSAvoidcomplexity of additive manufacturing process

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes composite materials by combining different alloy compositions within the same additive manufacturing process. The stent body and connectors are built as an integrated structure with varying material compositions, enabling selective removal of connectors through controlled mechanical deformation.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If chemical etching is used to remove connectors, then connectors can be dissolved without adversely affecting stent components, but the process is not always desirable and may have limitations

Engineering Contradiction:

Improveconnector removal capabilityVSAvoidapplicability of removal method

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces the chemical etching process with a mechanical removal method. By designing connectors with controlled ductility, the connectors can be selectively removed through mechanical deformation (bending, twisting, or shearing) without requiring chemical treatments, making the process more versatile and avoiding chemical handling complexities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effective removal of connectors during the additive manufacturing process, simplifying the production of stents with desired structural characteristics.

Implementation Method 1

The second connector is formed such that the second connector is less ductile/more brittle than the first portion, the second portion, and the first connector

Methodology Applied

Scientific EffectIncomplete fusion: Sintering

Implementation Method 2

material selection for intermetallics in the second connector

Methodology Applied

Scientific EffectIntermetallics formation: Chemical Bonding

Implementation Method 3

selection of materials such that exposure to hydrogen in a heated environment causes the second connector to be less ductile than the first connector

Methodology Applied

Scientific EffectHydrogen embrittlement: Hydrogenation

Data Source

PatentUS10675707B2Method of making a medical device using additive manufacturing

Publication Date: 2020.06.09 MEDTRONIC VASCULAR INC

AI summary

A method of making a medical device includes forming a precursor medical device using additive manufacturing. The precursor medical device includes a first portion, a second portion, a first connector, and a second connector. The first connector connects the first portion to the second portion and is configured to remain. The second connector connects the first portion to the second portion and are configured to be removed. The second connector is formed such that the second connector is less ductile than the first portion, the second portion, and the first connector. The precursor medical device is processed to remove the second connector without adversely affecting the first portion, the second portion, and the first connector.