Modular Molding for Precise Tube-to-Fitting Overmolds
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Solution Overview
Problem
Existing fluid transfer assemblies face challenges in precise alignment of tubes during overmolding, limited fabrication flexibility, and difficulty in forming secure connections due to the use of mechanical supports and overmolding processes.
Innovation Solution
The use of a fitting with a locating feature and flanges, combined with injection molding and thermal bonding, allows for precise alignment and formation of overmolds that securely connect tubes to fittings without mechanical supports, enabling consistent overmold dimensions and thermal bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If overmolding process with removable internal support is used, then tubing connections can be formed, but the internal support limits the applications and reduces fabrication flexibility
Solution Approach 1:
The patent removes the removable internal support component from the mold structure entirely. Instead of using a complex mold with extractable supports, the invention uses a simplified mold that forms the overmold directly around tubing already positioned on the fitting, eliminating the support structure complexity while maintaining connection formation capability
Solution Approach 2:
The tubing is pre-positioned on the fitting using locating features (protrusions and recesses) before the overmolding process begins. This preliminary positioning eliminates the need for internal supports during molding, as the tubing is already correctly aligned and secured in place prior to material injection
2Manufacturing precision
If mechanical connections with hose barb connectors are used, then tubing can be secured, but alignment precision and connection security are limited
Solution Approach 1:
The patent combines the positioning and securing functions into a single integrated locating feature system. The protrusions on the fitting and corresponding recesses on the tubing create both precise alignment and mechanical retention in one feature set, eliminating the need for separate hose barb connectors and cable ties while achieving superior alignment precision
Solution Approach 2:
The locating features (protrusions and recesses) act as intermediaries between the fitting and tubing, providing precise alignment and secure positioning before overmolding. These features mediate the connection process, ensuring accurate tube-to-fitting alignment without requiring complex mechanical fastening systems
3Productivity
If tubing is fitted over hose barb connector with cable tie, then mechanical securing is achieved, but the connection process becomes complex and time-consuming
Solution Approach 1:
The patent merges multiple connection functions (positioning, securing, and sealing) into a single integrated process. The locating features provide mechanical retention, the overmold provides sealing and additional securing, all in one operation, eliminating the need for separate hose barb connectors and cable ties while reducing assembly steps and time
Solution Approach 2:
The connection system is segmented into distinct functional elements: locating features for positioning and retention, and overmold material for sealing and reinforcement. This segmentation allows each element to perform its specific function efficiently, simplifying the overall connection process compared to integrated mechanical fastening systems
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 ensures precise alignment and secure connections between tubes and fittings, reducing the need for post-processing and enhancing fabrication flexibility, while allowing for various connector types and components like filters or pressure gauges.
Implementation Method 1
a mold is placed over the fitting and tube assembly such that the tube is contained within the mold and the projection is received within a depression in the mold, after which an overmold is formed using an injection molding process
Implementation Method 2
The overmold is bonded to the tube and the fitting is thermal bonded to the overmold
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
A tubing including an overmold is connected to a fitting by welding the overmold to the fitting. Methods for doing the same are also provided. Also provided are methods for forming an overmold on a tubing or on a tubing and fitting assembly.