Multi-Lumen Tube Extrusion for Circular Outer Shape Control
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Solution Overview
Problem
Existing extrusion molding apparatuses struggle to produce multi-lumen tubes with an outer shape close to a perfect circle, leading to deformation and resin breakage issues, especially when increasing conduit numbers or reducing tube diameter.
Innovation Solution
An extrusion molding apparatus with a die, outer surface molding apparatus, gas supplying apparatus, and depressurizing apparatus, utilizing mold blocks or flexible belts to mold the outer surface of multi-lumen tubes into a perfect circular shape by injecting gas and depressurizing the molding space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If air is injected from conduit forming members during extrusion molding, then conduits are formed with proper shape, but the uncured tube deforms and the outer shape cannot be made a perfect circle
Solution Approach 1:
The outer surface of the tube is molded into a circular shape before the resin is fully cured. The molding apparatus applies pressure to the uncured resin to form the circular outer shape, and then the resin is allowed to cure while maintaining this shape. This preliminary molding action ensures the outer shape is circular before the resin hardens and can no longer be deformed.
Solution Approach 2:
The forming process is divided into separate stages: first, the conduit forming members inject air to create the conduit shapes; second, the molding apparatus independently molds the outer surface into a circular shape. This segmentation allows each function (conduit formation and outer shape molding) to be performed without interfering with the other, resolving the conflict between forming conduits and maintaining circular outer shape.
2Volume of moving object
If the outer shape of the tube is made smaller or the number of conduits is increased, then the tube becomes more suitable for medical applications, but the resin portion thickness becomes thin and the resin breaks easily
Solution Approach 1:
The molding apparatus applies pressure locally to the outer surface of the tube at the resin portion, reinforcing this area without increasing the overall tube diameter or affecting the conduit configurations. This localized reinforcement increases the resin portion thickness and strength in the critical outer region while maintaining the small tube size and multiple conduits needed for medical applications.
Solution Approach 2:
The resin portion is molded and reinforced before the tube is fully cured. By applying pressure to the uncured resin, the molding apparatus can effectively increase the resin portion thickness and strength. Once cured, the resin maintains this reinforced structure, providing the necessary strength for small-diameter, multi-conduit tubes used in medical applications.
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
The apparatus produces multi-lumen tubes with a circular cross-section, preventing resin breakage and ensuring consistent shape, particularly suitable for medical applications with small diameters and multiple conduits.
Implementation Method 1
a gas is supplied from the gas supplying apparatus to each of the conduit molding members, the supplied gas is injected from front ends of the penetrating holes
Implementation Method 2
the molding space is depressurized by the depressurizing apparatus to put the outer surface of the multi-lumen tube contained in the molding space in close contact with inner surfaces of the grooves
Data Source
AI summary
Provided is an extrusion molding apparatus capable of producing a multi tube with which an outer shape of a cross section is close to a perfect circle. The multi-lumen tube extrusion molding apparatus includes a resin supplying portion, a die that has an extrusion port at a lower end portion and molds the multi-lumen tube as the resin supplied from the resin supplying portion is extruded vertically downward, and an outer surface molding apparatus that molds an outer surface of the extruded tube. In a state in which the resin is supplied from the resin supplying portion to the die, the outer surface molding apparatus depressurizes a molding space of circular cylindrical shape in a state in which the extruded tube is contained in the molding space to mold an outer surface of the contained multi-lumen tube to a circular cylindrical shape.