Plastic Tube Connection via Forming Process
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Solution Overview
Problem
Existing methods for connecting plastic tubes in medical catheters, particularly those with different material properties, face challenges in achieving a secure and simple connection, especially with small diameters, as traditional welding and gluing require compatible materials and are complex to apply accurately.
Innovation Solution
A forming process is used to deform plastic tubes onto a tubular connecting piece, creating an adhesive and/or form-fitting connection that maximizes contact surfaces for secure bonding, allowing for connections between chemically different materials without the need for adhesives or precise welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is used to connect plastic tubes, then a secure connection is achieved, but the method is only possible if the plastic tubes have very similar chemical structures and require complex development processes to determine compatible material combinations
Solution Approach 1:
A tubular connecting piece made of a third material (e.g., PTFE) is introduced as an intermediary between two plastic tubes with different material properties. The connecting piece enables connection between chemically incompatible materials by serving as a neutral interface that both tubes can bond to through the forming process, eliminating the need for direct material compatibility between the two tubes.
Solution Approach 2:
The forming process changes the physical state of the plastic tube material during connection. By heating the plastic tube to its forming temperature range, the material becomes pliable and can be deformed onto the tubular connecting piece, creating a secure mechanical interlock and adhesive bond without requiring chemical compatibility with the connector material.
2Adaptability or versatility
If gluing is used to connect plastic tubes, then greater flexibility in material selection is achieved, but the precise application of adhesive is complex especially with small diameters
Solution Approach 1:
The adhesive application process is replaced with a mechanical forming process. Instead of applying adhesive precisely to small-diameter tubes, the plastic tube is heated and mechanically deformed onto the tubular connecting piece, creating a secure bond through plastic deformation and mechanical interlocking that is far easier to control and apply accurately.
Solution Approach 2:
The connection method changes from chemical bonding (adhesive) to thermal-mechanical bonding. By changing the temperature parameter to the plastic tube's forming range and applying mechanical force, the connection is achieved through material deformation and cooling, eliminating the precision requirements of adhesive application.
3Adaptability or versatility
If traditional connection methods are used, then connections between different materials are achieved, but the process is complex and time-consuming
Solution Approach 1:
Multiple operations are merged into a single forming process step. The heating, deformation, bonding, and cooling operations are combined into one continuous process where the plastic tube is heated and formed onto the tubular connecting piece in a single operation, dramatically reducing the time and complexity compared to separate adhesive application or welding steps.
Solution Approach 2:
The forming temperature parameter enables a single-step process. By heating the plastic tube to its forming temperature range, all connection operations (heating, deformation, bonding) occur simultaneously during the forming process, eliminating the need for multiple separate steps and increasing productivity.
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 provides a flexible, secure, and adhesive-free connection with high mechanical stability, suitable for thin plastic tubes, enhancing the reliability and ease of production for medical catheters by eliminating the complexity of adhesive application and material compatibility issues.
Implementation Method 1
The first plastic tube and/or the second plastic tube are preferably softened during the forming process by a heat treatment and formed onto the tubular connecting piece
Implementation Method 2
In this context, the term forming process or forming refers to a process in which a body, e.g. B. a plastic tube, is plastically deformed in a targeted manner and brought into a new shape
Data Source
Figure 1a~1d
Figure 2a~2e
Figure 3~4
AI summary
A method for coaxially connecting a first plastic tube (10, 110) with a second plastic tube (20, 120), which plastic tubes (10, 20) are intended in particular as components of a medical catheter (102), wherein the two plastic tubes (10, 20) are connected via a tubular connecting piece (50), is characterized in that the first plastic tube (10) and/or the second plastic tube (20) are formed onto the tubular connecting piece (50) from the outside in a forming process, so that an adhesive and/or form-fitting connection is formed.