Catheter Bond Interface With Undercuts to Prevent Delamination

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Solution Overview

Problem

Catheter parts bonded via butt joints are prone to delamination due to small surface area, which can be exacerbated by bending and twisting forces, and existing surface processing methods to enhance bonding strength are costly and inefficient.

Innovation Solution

Incorporating radially oriented undercut structures, such as T- or L-shapes, on the edge surfaces of catheter parts to create interlocking features that enhance bond resilience, using a bonding material to fill these undercuts and reinforce the bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If butt joints are used to bond catheter parts, then the manufacturing process is simple, but the bond strength is insufficient and delamination occurs due to small surface area

Engineering Contradiction:
Improvebonding process simplicityVSAvoidbond strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent transitions from a conventional planar bonding surface to a three-dimensional interlocking structure by forming undercut features (such as T-shaped, L-shaped, or interdigitating patterns) on the bonding surfaces of catheter parts. This dimensional transformation increases the effective bonding area and creates mechanical interlocking that prevents delamination while maintaining manufacturing simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If surface processing methods are used to enhance bonding strength, then bond strength improves, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvebond strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The undercut bonding features are integrated into the catheter part design during the molding or fabrication process itself, rather than being added as a separate post-processing step. This preliminary incorporation of the interlocking structure eliminates the need for additional surface treatment operations, thereby reducing manufacturing complexity while achieving enhanced bond strength.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If conventional bonding surfaces are used, then manufacturing is cost-effective, but the bonds fail under bending and twisting forces

Engineering Contradiction:
Improvemanufacturing cost-effectivenessVSAvoidbond reliability under flexure
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs asymmetric undercut patterns (such as T-shaped or L-shaped features) on the bonding surfaces that create directional interlocking. These asymmetric geometries provide resistance to multi-directional forces including bending and twisting, while the features are designed to be formed through standard manufacturing processes, maintaining cost-effectiveness.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3813921B1Catheter elements for bond-strength enhancement
Publication Date: 2026.04.22 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP3813921B1 patent drawingFigure 1
  • EP3813921B1 patent drawingFigure 2A~2B
  • EP3813921B1 patent drawingFigure 3

AI summary

A catheter manufacturing method includes the step of providing a hollow cylindrical part of a catheter, having a longitudinal axis, to be bonded to a given part along respective edge surfaces of the hollow cylindrical and the given parts. One or more undercut structures that are disposed circumferentially with respect to the longitudinal axis and also generally parallel to the longitudinal axis, the undercut structures having a radial orientation with respect to the longitudinal axis, are formed at least in the edge surface of the hollow cylindrical part. The hollow cylindrical part and the given part are connected using the undercut structures.