Shape Memory Polymer Mandrel for Complex Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing molding techniques face challenges in efficiently forming complex or intricate shapes, such as S-shaped or curved tubes with non-constant cross-sections, due to high costs and energy consumption, and are unsuitable for parts with similar geometries, as they often result in die lock or require costly preform manufacturing processes.
Innovation Solution
The method involves using a perforated shape memory polymer mandrel with a removable shrunken permanent shape and a bladder, either flexible or made of shape memory polymer, which is inserted into an external mold to block perforations, allowing resin to impregnate and cure, forming a molded part without die lock, and enabling the formation of complex shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional molding techniques are used to form complex or intricate shapes, then the manufacturing process can handle simple geometries, but the cost and energy consumption increase undesirably
Solution Approach 1:
The mandrel utilizes shape memory polymer material that can dynamically change its shape between temporary and permanent states through temperature control. This dynamic shape transformation allows the same mandrel to form various complex geometries without requiring multiple specialized tools, thereby reducing manufacturing costs while maintaining versatility for intricate shapes.
Solution Approach 2:
The invention changes the temperature parameter to trigger the shape memory effect in the mandrel material. By heating the mandrel above its transition temperature, it transforms from its temporary shape to its permanent shrunken shape, enabling easy removal. This parameter change allows the system to adapt to different complex geometries without increasing cost or energy consumption significantly.
2Adaptability or versatility
If traditional preforming techniques with articulated screens are used, then simple preforms can be manufactured, but complex or S-shaped geometries are not amenable to being formed
Solution Approach 1:
The invention employs a flexible bladder within the mandrel structure that can be inflated or pressurized to assume complex shapes during the molding process. This flexible element allows the mandrel to form intricate geometries including S-shaped and curved tubes with non-constant cross-sections, while the overall manufacturing process remains simple and cost-effective.
Solution Approach 2:
The mandrel's shape memory polymer material provides dynamic adaptability, allowing it to be deformed into various temporary shapes for different complex geometries, then automatically return to its permanent shrunken shape for easy removal. This dynamic behavior enables the formation of intricate geometries without requiring complex manufacturing processes or articulated screens.
3Ease of operation
If a solid mandrel is used in molding, then the preform can be supported during resin injection, but the mandrel cannot be easily removed from the finished part
Solution Approach 1:
The mandrel material undergoes a phase transition at its shape memory temperature, changing from a rigid state that provides reliable preform support during molding to a flexible state that enables easy removal after curing. By heating the mandrel above its transition temperature, it transforms to its permanent shrunken shape, creating clearance for straightforward extraction from the finished part while maintaining preform support integrity during the molding process.
4Productivity
If multiple preform pieces are assembled together, then enclosed or tubular preforms can be formed, but the manufacturing process becomes time-consuming and costly
Solution Approach 1:
The shape memory polymer mandrel serves multiple functions: it provides internal support during preform formation, enables formation of enclosed and tubular geometries in a single piece, and facilitates easy removal after molding. This universal, multi-functional mandrel eliminates the need for assembling multiple preform pieces, significantly improving manufacturing efficiency while reducing process complexity.
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 approach allows for the efficient formation of complex shapes without die lock, reduces manufacturing costs and energy consumption, and facilitates the production of parts with intricate geometries by using shape memory polymers that can be reconfigured for various part shapes.
Implementation Method 1
The shape memory polymer mandrel has i) the predetermined part shape as the temporary shape and ii) a shrunken shape as its permanent shape
Implementation Method 2
Resin is injected into the external mold between an inner surface of the external mold and an outer surface of the preform such that the resin impregnates the preform. The injected resin is cured, thereby forming a molded part.
Data Source
AI summary
A molding method includes inserting a preform having a predetermined part shape into an external mold having the predetermined part shape. The preform has therein a perforated shape memory polymer mandrel in its temporary shape, and a bladder positioned within the perforated shape memory polymer mandrel. The shape memory polymer mandrel has i) the predetermined part shape as the temporary shape and ii) a shrunken shape as its permanent shape, wherein the shrunken shape is configured such that it is removable from the predetermined part shape. The method further includes configuring the bladder such that it substantially blocks perforations of the mandrel in its temporary shape, injecting resin into the external mold between an inner surface of the external mold and an outer surface of the preform such that the resin impregnates the preform, and curing the injected resin, thereby forming a molded part.