Fluororesin Bonded Body Joining to Prevent Gaps and Thermal Strain
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Solution Overview
Problem
Existing methods for bonding resin molded bodies made of different fluororesin materials face issues such as gap formation due to material hardness differences, thermal strain from temperature changes, and reduced strength at the joining interface, particularly in fluidic devices like valves.
Innovation Solution
A method involving a cup-shaped first resin assembly made of a gelling fluororesin material that accommodates a second resin assembly in a liquid state, both are heated above their melting points and then cooled to integrate the molded bodies, preventing gaps and thermal strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If two resin molded bodies made of different fluororesin materials are bonded by engagement of uneven surfaces, then the valve element portion can be made from particle-suppressing material, but fine gaps are generated between uneven surfaces due to hardness difference and thermal expansion, causing particle increase over time
Solution Approach 1:
The invention changes the bonding method from mechanical engagement of uneven surfaces to a bonding process that accounts for thermal expansion parameters. By heating both resin molded bodies to a temperature equal to or higher than their respective melting points simultaneously, the patent ensures that thermal expansion is uniform and gaps are prevented during cooling and solidification.
Solution Approach 2:
The patent applies equipotentiality by heating both resin molded bodies to the same temperature (equal to or higher than their melting points) simultaneously. This ensures that both materials experience equal thermal conditions during bonding, preventing differential thermal expansion that would cause gaps between the bonded surfaces.
2Strength
If resin molded bodies are bonded by melting interfaces using infrared beam or hot plate, then joining strength can be improved, but temperature difference between melted and unmelted portions causes thermal strain and reduces bonding interface strength
Solution Approach 1:
The invention merges the heating process for both resin molded bodies into a single simultaneous operation. By heating both bodies to their melting points at the same time using a heating device, the patent eliminates temperature differences between melted and unmelted portions, preventing thermal strain while maintaining bonding strength.
Solution Approach 2:
The patent employs a controlled heating and cooling cycle: both resin molded bodies are heated to melting points simultaneously, held at that temperature to ensure complete melting, then cooled together to allow controlled solidification. This periodic thermal action prevents thermal shock and maintains bonding interface integrity.
3Object-generated harmful factors
If valve element portion is made from PFA to suppress particle generation, then particle generation is reduced, but bending durability is insufficient for repeated elastic deformation
Solution Approach 1:
The patent applies local quality by assigning different fluororesin materials to different portions of the diaphragm based on their specific functional requirements. The diaphragm portion is made from PTFE for high bending durability, while the valve element portion is made from PFA for low particle generation. This localized material selection optimizes performance in each specific area.
Solution Approach 2:
The invention creates a composite structure by bonding two different fluororesin materials (PTFE and PFA) together. Each material contributes its superior properties to the final product: PTFE provides bending durability for the diaphragm portion, while PFA provides particle suppression for the valve element portion, achieving a synergistic effect that neither material could provide alone.
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 integrated resin bodies maintain strength and prevent gap formation, reducing the risk of particle generation and interface weakness, even under impact and temperature variation.
Implementation Method 1
a first fluororesin material that is capable of gelling and maintaining a shape even at a temperature equal to or higher than a melting point thereof
Implementation Method 2
heating the first resin assembly having the second resin assembly in the accommodation portion thereof, to a temperature equal to or higher than the melting points of the first fluororesin material and the second fluororesin material
Implementation Method 3
cooling the first resin assembly and the second resin assembly to change the first resin assembly to a first resin molded body and change the second resin assembly to a second resin molded body while joining the first resin molded body and the second resin molded body to each other
Data Source
AI summary
This method for producing a resin bonded body includes: forming a first resin assembly of a shape having an accommodation portion from a first fluororesin material that is capable of gelling and maintaining shape even at or above the melting point thereof; a step for accommodating a second resin assembly composed of a second fluororesin material that melts and becomes liquid at or above the melting point thereof within the accommodation portion. The method includes heating the first resin assembly having the second resin assembly disposed in the accommodation portion to or above the melting point of the first fluororesin material and the second fluororesin material before cooling the first resin assembly, changing the first resin assembly into a first resin molded body and the second resin assembly into a second resin molded body, and bonding the first and second resin molded bodies.