Co-Molded Button Membrane Assembly for Complex Housing Sealing
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Solution Overview
Problem
Conventional button assemblies face challenges in cost-effective and reliable molding of button membranes onto complex or inaccessible housing geometries, and suboptimal adhesion compatibility between elastomeric materials and hard plastics used for housings, which affects sealing and integrity.
Innovation Solution
A composite button component is formed with a pre-formed elastically flexible button membrane mounted on a rigid frame, and the housing is molded over this insert, establishing a watertight connection, allowing for better material selection and adhesion compatibility through co-molding and overmolding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a button membrane is directly molded onto a housing, then sealing engagement is achieved, but manufacturing complexity increases and reliability decreases due to complex or inaccessible housing geometries
Solution Approach 1:
The button assembly is segmented into a button membrane and a button frame that is integrated into the housing. The button membrane is molded onto the button frame rather than directly onto the housing, separating the sealing function from the complex housing geometry and enabling reliable sealing engagement.
2Duration of action of moving object
If elastomeric material is used for the button membrane, then resilient return is achieved, but adhesion compatibility with hard plastics housing materials deteriorates
Solution Approach 1:
The button frame acts as an intermediary between the elastomeric button membrane and the hard plastics housing. The membrane is bonded to the button frame (which can be made of compatible materials), and the frame is integrated into the housing, mediating the adhesion interface and resolving material incompatibility.
3Reliability
If conventional direct molding is used, then sealing is achieved, but manufacturing cost and difficulty increase due to inaccessible housing geometries
Solution Approach 1:
The manufacturing process is segmented into two stages: first molding the button frame with integrated features, then molding the button membrane onto the frame. This avoids the need to directly mold onto complex housing geometries, simplifying the manufacturing process and reducing costs while maintaining sealing reliability.
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 enhances manufacturing ease, reliability, and sealing integrity, while allowing for a wider range of material selection and minimizing the overall size of the button assembly, with improved tactility and re-centering functionality.
Implementation Method 1
resilient return of the push button subsequent to pressing is effected by a resilient membrane or elastomer gasket that is deformed when the button is pressed
Implementation Method 2
the button membrane being overmolded on to the button frame
Data Source
AI summary
A method of manufacturing a button-enabled housing assembly includes pre-forming a composite button component or insert having an elastically flexible button membrane that is mounted on a rigid frame, and thereafter molding a housing over the button insert. The composite button insert is formed in a co-molding operation and can include a rigid island in the flexible button membrane for supporting a cosmetic keycap.