Intravascular Beam Cut Pattern for Flexibility and Fatigue Life
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Solution Overview
Problem
Existing intravascular devices face challenges in navigating tortuous vasculature due to insufficient flexibility, particularly at the distal end, despite microfabrication techniques to increase flexibility, which often result in sharp edges and structural weak points.
Innovation Solution
Intravascular devices with enhanced one-beam cut patterns are manufactured using a dual-pass cutting method, forming beams with reduced angles between lateral and interior surfaces, minimizing sharp edges and structural weak points, and ensuring uniform thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-pass cutting is used to create fenestrations, then manufacturing is simpler and faster, but the resulting sharp edges create structural weak points that reduce device flexibility and fatigue life
Solution Approach 1:
The cutting process is segmented into two distinct passes: a roughing pass that removes the majority of material to create the fenestration, and a finishing pass that creates the critical rounded edges. This segmentation allows each pass to be optimized for its specific function, resolving the contradiction between simple manufacturing and high reliability.
Solution Approach 2:
The roughing pass performs preliminary material removal to create the basic fenestration shape before the finishing pass. This preliminary action prepares the workpiece for the subsequent precision operation, enabling the finishing pass to focus solely on creating the rounded edges that eliminate stress concentrations.
2Manufacturing precision
If traditional single-pass cutting is used, then manufacturing time is reduced, but cut accuracy and edge quality are insufficient, leading to structural weak points
Solution Approach 1:
The cutting operation is divided into two passes with distinct objectives: the roughing pass prioritizes material removal efficiency, while the finishing pass prioritizes edge quality and precision. This segmentation allows each pass to be tuned for its specific requirement, achieving both high precision and acceptable productivity.
Solution Approach 2:
Cutting parameters such as feed rate, depth of cut, and blade speed are changed between the two passes. The roughing pass uses parameters optimized for rapid material removal, while the finishing pass uses parameters optimized for precise edge formation, thereby achieving high manufacturing precision without excessive time penalty.
3Ease of manufacture
If beams have sharp edges from traditional cutting, then manufacturing is easier, but the sharp edges create stress concentrations that reduce device flexibility
Solution Approach 1:
The manufacturing process is segmented into roughing and finishing passes, where the roughing pass creates the basic shape easily, and the finishing pass adds the rounded edges for strength. This segmentation maintains ease of manufacture while eliminating the harmful sharp edges.
Solution Approach 2:
The second cutting pass intentionally creates a controlled material removal pattern that rounds the edges. What could be seen as an additional complex step is actually converting the harmful sharp edges into beneficial rounded transitions, eliminating stress concentrations and improving structural strength.
Data Source
AI summary
Disclosed are intravascular devices having enhanced one-beam cut patterns. An elongated member includes a plurality of fenestrations that define a plurality of axially extending beams interspersed between a plurality of circumferentially extending rings. The beams are formed using a dual-pass cutting method in which a blade makes two, rotationally offset cutting passes at a given longitudinal location of the elongated member. The resulting beam has enhanced structure that avoids overly sharp edges and minimizes structural weak points.