Overmolded Stent Catheter Tip with Dual Durometer
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Solution Overview
Problem
Current stent deployment systems are expensive and require skilled technicians for handmade catheter assemblies due to the complex attachment of a soft tip to the catheter, which involves precise glue application and shaping.
Innovation Solution
A stent deployment system with an overmolded tip where a polyether block amide tip is molded onto an untreated external surface of a thermosetting polyimide elongate tube, using a two-step process to create a molecularly joined structure with varying durometer hardness, eliminating the need for anchor features on the tube and allowing for easier manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft tip is attached to the catheter using precise glue application by skilled technicians, then the catheter assembly achieves reliable attachment and proper functionality, but the manufacturing cost increases and production complexity increases
Solution Approach 1:
The patent replaces the manual mechanical process of glue application and shaping with an automated overmolding process. The tip is molded directly onto the catheter assembly using heat and pressure, eliminating the need for skilled technicians to apply and shape glue manually. This substitution of mechanical/manual processes with a molded manufacturing process resolves the contradiction by maintaining reliable attachment while dramatically improving ease of manufacture.
Solution Approach 2:
The patent changes the manufacturing parameters from manual glue application (controlled by technician skill) to controlled molding parameters (temperature, pressure, time). The overmolding process uses specific temperature ranges and pressure levels to achieve proper attachment of the tip to the catheter, transforming the attachment method from a skill-dependent manual process to a parameter-controlled automated process. This resolves the contradiction by ensuring consistent reliable attachment while simplifying manufacturing.
2Manufacturing precision
If a soft tip is attached to the catheter using precise glue application and shaping, then the catheter assembly achieves the required structural integrity and tip positioning, but the manufacturing time increases and productivity decreases
Solution Approach 1:
The patent incorporates the tip attachment step into the preliminary molding process itself. Rather than attaching the tip after catheter assembly (as in the manual glue method), the tip is molded onto the catheter assembly during the initial manufacturing process. This preliminary action integrates multiple steps into one continuous process, maintaining precise tip positioning while eliminating subsequent manual operations, thereby increasing productivity.
Solution Approach 2:
The patent merges the tip attachment operation with the catheter assembly manufacturing process. The overmolding process combines the formation of the catheter structure and the attachment of the tip into a single integrated manufacturing step. This merging eliminates the sequential nature of the manual process (assemble catheter, then attach tip), allowing both operations to occur simultaneously and improving production speed while maintaining precision.
3Adaptability or versatility
If a soft tip is attached to the catheter using manual glue application, then the catheter assembly can be customized with specific tip characteristics, but the device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent maintains tip customization capability through the overmolding process by allowing different materials, durometers, and geometries to be molded onto the catheter assembly. The molding process can produce tips with specific local properties (hardness, shape, size) tailored to different applications. This local quality approach maintains adaptability while simplifying the overall manufacturing process by using a single integrated method rather than multiple specialized manual operations.
Solution Approach 2:
The overmolding process serves multiple functions simultaneously: it attaches the tip to the catheter, forms the tip's final shape and geometry, and can incorporate different materials or durometers as needed. This universal process replaces multiple specialized manual operations (cutting, shaping, attaching, sealing), reducing device complexity while maintaining the ability to customize tip characteristics for different applications.
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 manufacturing costs and complexity, enabling more uniform and cost-effective production of catheter assemblies with a flexible and recognizable tip structure, while maintaining effective stent deployment functionality.
Implementation Method 1
The tip includes a proximal portion molecularly joined to a distal portion, which has a lower durometer hardness than the proximal portion
Data Source
AI summary
A deployment system for a self expanding stent includes a catheter assembly with a tip attached to a distal end segment of an elongate tube. The tip includes a proximal portion molecularly joined to a distal portion, which has a lower durometer hardness than the proximal portion. The proximal portion includes an anchor surface in contact with the distal portion, and oriented perpendicular to a central axis of the elongate tube. The elongate tube may be formed from a thermosetting polyimide, and the overmolded tip may be made from two different colored and different hardnesses of polyether block amide material. The tip is overmolded onto an untreated external surface of the elongate tube.