Medical Catheter Inner Layer Cooling During Reinforcement Annealing

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Solution Overview

Problem

The existing methods for manufacturing medical elongated bodies, such as catheters, face challenges in preventing the melting of the inner layer due to the annealing process, especially when using thermoplastic resin with a low melting point, which can lead to defects and reduced yield.

Innovation Solution

A method that involves cooling specific spots of the inner layer before the annealing process, using a coolant with a temperature of -10° C. or lower, such as liquid nitrogen, to prevent the inner layer from melting during the annealing of the reinforcement body, thereby maintaining the molding state and ensuring high yield production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an annealing process is performed on the reinforcement body to prevent jumping of wires, then the reinforcement wires can be well coated with the outer layer, but heat is transferred to the inner layer causing unintended spots to melt or burn

Engineering Contradiction:

Improveprevention of reinforcement wire jumpingVSAvoidmelting or burning of inner layer

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The inner layer is cooled to -10°C or lower before the annealing process is applied to the reinforcement body. This preliminary cooling action creates a temperature buffer that prevents heat transfer from melting the inner layer during subsequent annealing, while still allowing the reinforcement wires to be properly coated

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The temperature parameter of the inner layer is changed to -10°C or lower before annealing. This parameter change allows the inner layer to withstand the heat transfer during annealing without melting, resolving the contradiction between achieving reliable wire coating and preventing inner layer damage

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If thermoplastic resin is used for the inner layer to enable easy molding and low cost manufacturing, then manufacturing cost and ease of molding are improved, but the low melting point causes the material to melt during the annealing process

Engineering Contradiction:

Improveeasy molding and low costVSAvoidmelting point

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The inner layer made of thermoplastic resin is preliminarily cooled to -10°C or lower before annealing. This preliminary cooling enables the use of low-cost thermoplastic materials while preventing them from melting during the subsequent annealing process, as the temperature buffer protects the low melting point material

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The temperature parameter of the thermoplastic resin inner layer is changed to -10°C or lower, which allows the material to withstand annealing temperatures without melting. This parameter change resolves the contradiction between using low-cost thermoplastic materials and preventing melting during annealing

Inventive Principle:

Principle #35Parameter changes

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 effectively prevents the inner layer from melting during the annealing process, allowing for the successful use of thermoplastic resin with low melting points, ensuring high accuracy and cost-effective manufacturing of medical elongated bodies while maintaining the structural integrity of the catheter.

Implementation Method 1

a cooling step of cooling at least a predetermined spot of the inner layer after the reinforcement body forming step

Methodology Applied

Scientific EffectCooling: Cooling

Implementation Method 2

when the annealing step is performed, it is possible to prevent the melting of the inner layer by performing the cooling step of cooling the predetermined spot of the inner layer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

an annealing step of annealing the reinforcement body which overlaps the predetermined spot of the inner layer cooled by the cooling step

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 4

since heat is transferred to an inner layer from a reinforcement body, unintended spots of the inner layer may melt or burn

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10485947B2Method for manufacturing medical long body

Publication Date: 2019.11.26 TERUMO KK

AI summary

A method of manufacturing a medical elongated body including an inner layer, an outer layer covering the outside of the inner layer, and a reinforcement body provided between the inner layer and the outer layer. The method includes an inner layer forming step of forming the inner layer, a reinforcement body forming step of forming the reinforcement body on an outer peripheral surface of the inner layer after the inner layer forming step, a cooling step of cooling at least a predetermined spot of the inner layer after the reinforcement body forming step, and an annealing step of annealing the reinforcement body which overlaps the predetermined spot of the inner layer cooled by the cooling step.