Crosslinked Overmolded Polymer Assembly Radiation Control
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Solution Overview
Problem
Existing methods for crosslinking polymer assemblies using radiation result in non-uniform crosslinking percentages across components due to varying wall thicknesses and orientations, leading to increased costs and potential connection failures in applications like pressurized water fittings.
Innovation Solution
A process where a molded assembly of polymeric components is oriented at an angle relative to the electron beam direction and exposed multiple times to deliver a predetermined, constant amount of radiation, allowing independent control of crosslinking percentages by varying parameters such as wall thickness, antioxidant concentration, and shielding, ensuring each component meets specific performance parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If components are crosslinked separately to achieve minimum 65% crosslinking, then each component meets performance requirements, but crosslinked components have limited ability to form bonded connections
Solution Approach 1:
The patent applies preliminary action by performing overmolding and bonding operations before crosslinking. The assembly is prepared with components in their uncrosslinked state, allowing thermoplastic bonding sites to be available for robust material-to-material bonds. Crosslinking is then applied afterward to achieve the required 65% minimum crosslinking percentage, ensuring both strong bonds and performance requirements are met.
Solution Approach 2:
The patent employs dynamics by controlling the timing and sequence of operations. The process dynamically transitions from a state where components are uncrosslinked and bondable to a state where they are crosslinked and performance-optimized. This temporal control allows the system to exploit the beneficial properties of each state at the appropriate stage.
2Productivity
If chemical crosslinking is used during extrusion and molding, then crosslinking occurs during assembly processes, but increasing crosslink percentage reduces thermoplastic bonding sites for melt fusion
Solution Approach 1:
The patent applies preliminary action by performing overmolding and bonding operations before crosslinking. The assembly is prepared with components in their uncrosslinked state, allowing thermoplastic bonding sites to be available for robust material-to-material bonds. Crosslinking is then applied afterward to achieve the required 65% minimum crosslinking percentage, ensuring both strong bonds and performance requirements are met.
Solution Approach 2:
The patent employs dynamics by controlling the timing and sequence of operations. The process dynamically transitions from a state where components are uncrosslinked and bondable to a state where they are crosslinked and performance-optimized. This temporal control allows the system to exploit the beneficial properties of each state at the appropriate stage.
3Manufacturing precision
If assemblies are exposed to electron beam multiple times to achieve uniform crosslinking, then crosslinking percentage is controlled, but process time increases
Solution Approach 1:
The patent applies preliminary action by performing overmolding and bonding operations before crosslinking. The assembly is prepared with components in their uncrosslinked state, allowing thermoplastic bonding sites to be available for robust material-to-material bonds. Crosslinking is then applied afterward to achieve the required 65% minimum crosslinking percentage, ensuring both strong bonds and performance requirements are met.
Solution Approach 2:
The patent employs dynamics by controlling the timing and sequence of operations. The process dynamically transitions from a state where components are uncrosslinked and bondable to a state where they are crosslinked and performance-optimized. This temporal control allows the system to exploit the beneficial properties of each state at the appropriate stage.
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 enables cost-effective, uniform crosslinking of polymer assemblies, ensuring each component achieves the desired crosslinking percentage, enhancing performance and reliability in applications like pressurized systems without the need for separate crosslinking of components.
Implementation Method 1
exposing the oriented assembly a number of times (N) to the electron beam operable to deliver a predetermined and substantially constant amount of radiation (R) in the electron beam direction
Implementation Method 2
crosslinking of less expensive polymers such as polyethylene has been practiced as a way to extend the life and performance of the polymer
Data Source
AI summary
A process for making a crosslinked assembly includes steps of: selecting a desired performance parameter for a molded assembly of a first polymeric component and a second polymeric component bonded to the first polymeric component, controlling a first crosslinking percentage for the first polymeric component and a second crosslinking percentage for the second polymeric component independently to provide the desired performance parameter for the assembly, orienting the assembly at an angle between an orientation axis of the assembly and a electron beam direction, exposing the oriented assembly a predetermined number of times (N) to the electron beam operable to deliver a predetermined amount of radiation (R) in the electron beam direction providing a total radiation exposure proportional to (N×R) providing the first component crosslinking percentage and the second component crosslinking percentage, the resulting assembly having the desired performance parameter.