Stent Graft Reinforcing Ring Electropolishing Design
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Solution Overview
Problem
Existing reinforcing rings for stent grafts, particularly those made from superelastic metals like Nitinol, face challenges in efficient electropolishing due to terminal loops that touch the wire, leading to incomplete surface treatment and potential damage to vascular tissues.
Innovation Solution
A reinforcing ring design featuring a substantially inextensible resilient wire with terminal loops and tails that can be folded back and spaced apart, allowing the ring to be straightened for comprehensive surface treatment without parts touching, enabling effective electropolishing and passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminal loops are provided on the wire to prevent puncture damage, then safety is improved, but electropolishing efficiency deteriorates because loops touch the wire and prevent complete surface treatment
Solution Approach 1:
The terminal end of the wire is segmented into two distinct components: a loop portion and a tail portion. The tail is folded back and extends around the circular shape, creating spatial separation between the loop and the wire body during electropolishing. This segmentation allows the loop to maintain its safety function while the tail prevents contact that would interfere with surface treatment.
Solution Approach 2:
The tail is configured to extend around the circular shape in a third-dimensional arrangement, creating spatial separation between the loop and the wire. When the ring is straightened for electropolishing, the tail wraps around the circular configuration, ensuring that no part of the loop or tail touches the wire, thereby enabling complete surface treatment in all dimensions.
2Adaptability or versatility
If the ring is made resilient to allow expansion and contraction, then deployability is improved, but manufacturing precision deteriorates due to difficulty in maintaining consistent surface treatment
Solution Approach 1:
The ring is pre-configured with the tail folded back and extending around the circular shape before surface treatment. This preliminary arrangement ensures that when the ring is straightened for electropolishing, the tail automatically positions itself to prevent contact between the loop/tail and the wire, guaranteeing complete and consistent surface treatment across all batches without requiring additional adjustment steps.
3Manufacturing precision
If the wire is straightened out for surface treatment, then electropolishing completeness is improved, but the loop structure may touch the wire causing treatment defects
Solution Approach 1:
The potential problem of loop-wire contact during electropolishing is extracted and addressed by adding the tail component. The tail is specifically designed to wrap around the circular shape and act as a spacer, extracting the contact issue from the system by providing a physical barrier that prevents the loop from touching the wire during the surface treatment process.
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 design allows for complete surface treatment of the reinforcing ring, enhancing biocompatibility and corrosion resistance, while preventing damage to vascular tissues during deployment.
Implementation Method 1
a metal known as a superelastic metal such as, but not restricted, to a nickel titanium alloy known as Nitinol... the wire on the former is heated above a temperature which sets the wire in the new shape. Upon cooling the ring holds it formed shape and can be distorted and resiliently returns to the formed shape
Implementation Method 2
the wire on the former is heated above a temperature which sets the wire in the new shape. Upon cooling the ring holds it formed shape
Data Source
AI summary
A reinforcing ring (10) for a fenestration (32) of a stent graft which can be surface treated such as by passivation and/or electropolishing. The reinforcing ring has several turns of a substantially inextensible resilient wire (12) in a circular two dimensional planar shape and terminal ends (14) at each end of the wire. The terminal ends each comprising a loop (14) and a tail (16). The tail is folded back and extends around the circular shape. Each of the tails of the terminal loops can have an enlarged end. The reinforcing ring can be straightened out for surface treatment such as passivation and/or electropolishing with substantially no part of the circular shape, the loops or tails touching each other.