Segmental Crimper with RF Heating for Catheter Balloon Bonding
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Solution Overview
Problem
Existing methods for bonding angioplasty balloon cuffs to catheters, such as those using hot jaws, hot air, or lasers, face issues with inconsistent bond strength due to heat transfer problems and variability in materials, making it difficult to achieve a reliable and consistent thermal bond.
Innovation Solution
A segmental crimping device with RF heating elements is used to radially compress and thermally bond the balloon cuff to the catheter, eliminating the need for heat shrink material while allowing for consistent hoop tension and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat shrink material is used to provide hoop tension for bonding, then thermal bonding can be achieved, but bond strength becomes inconsistent due to heat transfer problems and material variability
Solution Approach 1:
The crimper is divided into multiple independent heating segments (typically 3-6 segments) arranged circumferentially around the catheter-balloon assembly. Each segment can be independently controlled to apply heat and compression force, allowing precise local control of the bonding process and eliminating the heat transfer inconsistencies associated with traditional hot jaw clamps.
Solution Approach 2:
The patent replaces the mechanical hot jaw clamp system with a segmental crimper that uses radio frequency (RF) electromagnetic energy for heating. This substitution eliminates the need for direct thermal contact between the heating element and the material being bonded, solving the heat transfer control problems inherent in mechanical clamp systems.
2Temperature
If hot air is used for thermal bonding, then bonding can be achieved, but thermal control becomes difficult to maintain consistently
Solution Approach 1:
The patent replaces hot air heating with radio frequency (RF) electromagnetic heating. RF energy penetrates the material and generates heat internally through dielectric heating, providing precise and consistent temperature control without the difficulties of aiming and maintaining hot air flow. Each crimper segment contains RF heating elements that can be independently controlled.
Solution Approach 2:
The patent uses RF electromagnetic fields to change the heating mechanism from convective (hot air) to dielectric heating. This parameter change allows for precise control of heating rate and temperature distribution, as RF heating can be controlled by adjusting the electromagnetic field parameters (frequency, power, duration) without being affected by ambient conditions.
3Reliability
If laser is used for thermal bonding, then bonding can be achieved, but absorption rate varies with catheter properties affecting bond consistency
Solution Approach 1:
The patent replaces laser heating with radio frequency (RF) electromagnetic heating. RF energy interacts with the material through dielectric heating mechanisms that are less sensitive to surface properties such as pigment, texture, and reflectivity. This substitution ensures consistent heating across different catheter materials and surface characteristics.
Solution Approach 2:
The patent changes the electromagnetic heating parameter from optical frequency (laser) to radio frequency. This parameter change fundamentally alters the interaction mechanism with the material, making heating less dependent on optical properties (absorption, reflection, transmission) and more dependent on the material's dielectric properties, which are more consistent across different catheter formulations.
4Reliability
If heat shrink material is used to generate hoop tension, then bonding can be achieved, but bond properties vary with heat shrink material batch variations
Solution Approach 1:
The patent extracts and eliminates the heat shrink material from the bonding process. Instead of relying on heat shrink material to provide hoop tension, the segmental crimper directly applies compression force through its segments while RF heating elements provide the necessary heat for bonding. This removal of the heat shrink material eliminates the source of batch-to-batch variability.
Solution Approach 2:
The patent introduces the segmental crimper as an intermediary device that directly applies both mechanical compression and thermal energy to the catheter-balloon interface. This intermediary system provides controlled hoop tension and heat without requiring heat shrink material, eliminating the material property variability issue.
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 method enables rapid and consistent thermal bonding of angioplasty balloon cuffs to catheters with precise control over the bonding process, improving bond strength and reliability compared to prior techniques.
Implementation Method 1
Each of the crimper segments comprises a radio frequency heating element
Implementation Method 2
The crimper segments then heat and melt the balloon cuff to the catheter
Implementation Method 3
The crimper segments are movable relative to each other in a manner such that the crimper segments collectively define a variable size aperture
Data Source
AI summary
A segmental crimper comprises at least three crimper segments and an actuator. The crimper segments are arranged circumferentially about a crimper axis that defines axial and radial directions. The crimper segments are movable relative to each other in a manner such that the crimper segments collectively define a variable size aperture that is aligned with the crimper axis. Each of the crimper segments comprises a radio frequency heating element. The actuator is operatively connected to the crimper segments in a manner such that movement of the actuator causes all of the crimper segments to simultaneously move relative to each other and alters the size of the aperture.