Combined Injection Molding and Extrusion for Long Thin Parts
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Solution Overview
Problem
Injection molding is limited in producing long and thin parts, such as catheters, due to pressure drop within the cavity, which restricts the maximum fill length, making it difficult to manufacture these types of parts efficiently with detailed features.
Innovation Solution
A combined injection molding and extrusion process where molten material is initially injected into a mold and then pushed through an extrusion die to extend the part length, allowing for the separation of mold portions to facilitate longer and thinner part production with detailed features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If injection molding is used to produce parts, then detailed features and complex geometries can be achieved, but the maximum fill length is limited due to pressure drop within the cavity
Solution Approach 1:
The patent combines injection molding and extrusion processes into a single integrated system. The injection molding portion produces the molded article with detailed features, while the extrusion portion simultaneously produces a tubular structure that is joined to the molded article. This merging allows the production of long thin-walled structures with complex geometries that would be impossible with injection molding alone, as the extrusion process can produce continuous lengths without the pressure drop limitations of injection molding.
2Productivity
If traditional injection molding is used, then production speed is fast and efficient, but long and thin parts cannot be manufactured
Solution Approach 1:
The patent merges injection molding and extrusion in a co-injection process where both processes occur simultaneously in an integrated mold. The injection molding portion produces complex shaped articles quickly, while the extrusion portion produces continuous tubular structures of any length. This combination maintains the high productivity of injection molding while overcoming its length limitation, as the extrusion process can produce arbitrarily long thin-walled structures.
Solution Approach 2:
The patent segments the manufacturing process into two distinct but integrated portions: an injection molding portion for producing molded articles with complex geometries, and an extrusion portion for producing tubular structures. This segmentation allows each process to optimize its strengths while working together to produce the final long thin-walled product, overcoming the length limitation of injection molding while maintaining its productivity advantages.
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
Enables the efficient production of longer and thinner parts with detailed features, such as catheters, by overcoming the limitations of traditional injection molding in terms of maximum fill length and achieving complex geometries and surface finishes.
Implementation Method 1
a molten material is injected into a mold via an injection gate
Implementation Method 2
additional molten material is injected via the injection gate and pushed through an extrusion die located in the first portion of the mold
Data Source
AI summary
A method that combines injection molding and extrusion is disclosed. First, a molten material is injected into a mold via an injection gate, the mold comprising a first portion and a second portion. Next, additional molten material is injected via the injection gate and pushed through an extrusion die located in the first portion of the mold and the second portion is separated from the first portion. In embodiments, the second portion is separated from the first portion before the additional material is injected. In other embodiments, the second portion is separated from the first portion simultaneously with the additional material being injected. The method may be used to produce longer and thinner parts with detailed features, such as catheters.