Filled PTFE Mandrels for Thin-Wall Catheter Liner Tubes
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Solution Overview
Problem
Existing methods for producing thin-walled polymeric tubes, such as PTFE tubes, face challenges in removing the tubes from mandrels without using debonding agents, which can introduce contaminants. Additionally, these methods often result in tubes with insufficient strength and flexibility.
Innovation Solution
The use of a filled mandrel comprising PTFE with microparticles incorporated into it, which helps in creating a textured surface that allows for easier removal of the thin-walled PTFE tube without the need for debonding agents. The microparticles also enhance the mechanical properties of the tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional stainless steel or silver-plated copper wire mandrels are used to draw down PTFE preform, then thin-walled PTFE tubes can be produced, but the tubes are difficult to remove from the mandrels without using debonding agents
Solution Approach 1:
The mandrel is made of PTFE material, which is the same as the tube material being produced. This material homogeneity eliminates the adhesion problems between dissimilar materials (metal mandrel and PTFE tube), allowing the tube to be easily removed without debonding agents that would introduce contaminants.
Solution Approach 2:
The mandrel uses a composite structure of PTFE base material embedded with microparticles (such as glass beads, silica, or metal oxides). This composite material provides both the non-stick properties of PTFE and enhanced surface texture from the microparticles, facilitating tube removal while maintaining material compatibility.
2Ease of operation
If thin-walled PTFE tubes with wall thickness less than 0.004 inches are produced, then the tubes achieve desired flexibility, but the tubes have insufficient strength
Solution Approach 1:
The mandrel uses a composite material of PTFE with embedded microparticles (glass beads, silica, metal oxides, or clay). This composite structure provides enhanced mechanical properties and surface texture that transfer to the tube during the drawing process, improving the tube's strength while maintaining thin wall thickness for flexibility.
Solution Approach 2:
The microparticles are distributed throughout the mandrel material, creating localized reinforcement points that transfer surface texture and mechanical properties to the tube during the forming process. This local quality enhancement improves the tube's strength without requiring increased wall thickness.
3Ease of manufacture
If a textured surface is created on the mandrel to facilitate tube removal, then the coefficient of friction is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
Instead of mechanically creating complex textured surfaces through machining or molding, the patent uses a simpler approach: embedding microparticles directly into the PTFE mandrel material. This composite material approach creates the desired surface texture during manufacturing without requiring complex post-processing or specialized mandrel designs.
Solution Approach 2:
The surface properties of the mandrel are modified by changing the material composition (adding microparticles to PTFE) rather than changing the geometric complexity of the mandrel structure. This parameter change in material composition achieves the desired low-friction textured surface with minimal increase in device complexity.
Data Source
AI summary
The disclosure relates to assemblies of thin-walled tubes and mandrels for use in thin wall catheter liners. For example, an assembly is provided that includes a thin-walled PTFE tube comprising walls with a thickness of less than 0.004 inches, positioned over a filled mandrel comprising PTFE with one or more fillers incorporated therein. The disclosure further provides, independently, thin-walled tubes and filled mandrels, as well as methods of making and using such components.