Overmolding Polymeric Material onto Microcellular Polyurethane
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Solution Overview
Problem
Articles composed of polymeric materials and microcellular polyurethane, such as dampening devices, often experience separation due to adhesive failure under repeated compression, leading to reduced effectiveness in load absorption and vibration isolation.
Innovation Solution
A method of overmolding a polymeric material directly onto a microcellular polyurethane substrate, eliminating the need for adhesives by forming a mechanical or melt bond between the polymeric material and the microcellular polyurethane, which enhances the structural integrity and durability of the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is used to couple polymeric material component to microcellular polyurethane component, then assembly is simple and manufacturing is easy, but bond strength decreases and separation occurs under repeated compression
Solution Approach 1:
The patent merges the coupling function into the molding process itself by overmolding the polymeric material directly onto the microcellular polyurethane substrate. This integrates two previously separate operations (molding and adhesive bonding) into a single continuous process, eliminating the adhesive layer and creating a direct mechanical bond through the molding cycle.
Solution Approach 2:
The patent introduces a skin layer as an intermediary structure between the polymeric material and microcellular polyurethane. This skin layer, formed during overmolding, provides a bonding interface that mechanically couples the two materials without requiring separate adhesive application, thereby improving bond strength while maintaining manufacturing simplicity.
2Device complexity
If adhesive is used to join components, then manufacturing process is simple, but reliability decreases due to adhesive failure over time
Solution Approach 1:
The patent extracts the adhesive layer from the assembly process and replaces it with a direct overmolded bond. By removing the adhesive intermediary, the patent eliminates the source of time-dependent failure while maintaining process simplicity through integration of the bonding function into the molding operation.
Solution Approach 2:
The patent performs the bonding action during the initial molding process rather than as a subsequent separate step. The overmolding operation creates the bond between components during the same cycle in which the polymeric material is formed, ensuring bond reliability is established before the product enters service.
3Adaptability or versatility
If separate components are assembled with adhesive, then manufacturing flexibility is high, but cyclic stability decreases under repeated compression
Solution Approach 1:
The patent combines the polymeric material and microcellular polyurethane into a single integrated structure through overmolding. This merging creates a unified component with consistent mechanical properties throughout, eliminating the weak adhesive interface that would fail under cyclic loading while preserving the functional benefits of multi-material construction.
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 results in a stronger bond than traditional adhesives, reducing the likelihood of separation and improving the cyclic stability and load absorption capabilities of the dampening devices, while also simplifying the manufacturing process by eliminating adhesive application steps.
Implementation Method 1
the polymeric material is injected into the mold and over a receiving surface of the substrate in the molten state to form an overmolded element, which is coupled to the substrate
Data Source
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AI summary
An article is made by a method comprising the step of providing a substrate comprising a microcellular polyurethane. The method also includes the steps of placing the substrate into a mold and injecting a polymeric material into the mold and over a receiving surface of the substrate to form the overmolded element coupled to the substrate thereby making the article. The article is released from the mold.