Spray-Formed Acoustic Insulator Spring Layer
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Solution Overview
Problem
Existing methods for producing motor vehicle acoustic insulators with mass and spring components are costly due to complex mold requirements and inability to quickly adjust sound attenuation profiles, limiting high-volume manufacturing efficiency.
Innovation Solution
A motor vehicle acoustic insulator comprising a thermoplastic mass layer and a spray-formed thermoset polymer spring layer, allowing for localized adjustments in thickness and location without modifying tooling, using reactive components to form a bonded thermoset polymer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mold construction comprising a mold cavity with two separate lids is used to form mass and spring, then the acoustic insulator can be produced with mass and spring components, but the tooling costs increase and cycle time doubles
Solution Approach 1:
The acoustic insulator is divided into two distinct layers: a mass layer formed first, then a spring layer formed on top of it. This segmentation allows each layer to be formed separately in sequence using the same mold cavity, eliminating the need for two separate lids while maintaining the functional separation between mass and spring components.
Solution Approach 2:
The mass layer is formed in advance as a preliminary step before forming the spring layer. By completing the mass layer formation first and then adding the spring layer in the same mold cavity, the process eliminates the need for mold reconfiguration that would otherwise be required to form different layers with separate lids.
2Reliability
If a single mold cavity with two lids is used, then mass and spring can be formed, but the cycle time doubles reducing productivity
Solution Approach 1:
The mold cavity remains in the same position and configuration throughout the entire production cycle. The mass layer is formed, then the spring layer is formed continuously on top of it without requiring mold reconfiguration or lid changes, maintaining continuous useful action and eliminating cycle time doubling.
Solution Approach 2:
The mass layer is formed as a preliminary step that remains in place to serve as the base for the spring layer. This preliminary formation allows the spring layer to be added immediately afterward in the same mold cavity, eliminating the need to reset or reconfigure the mold between layers.
3Ease of manufacture
If molds are fixed after formation, then tooling costs are determined, but sound attenuation cannot be adjusted in newly uncovered locations
Solution Approach 1:
The spring layer thickness and composition can be dynamically adjusted after the mass layer is formed. By using spray foam technology, the spring layer can be applied with varying thicknesses at different locations based on newly identified sound attenuation requirements, allowing the acoustic insulator to be adapted without modifying the fixed mold structure.
Solution Approach 2:
The spring layer can be applied with locally varied properties, including different thicknesses and densities at different locations on the mass layer. This allows specific areas to be optimized for sound attenuation based on local requirements identified after production begins, without requiring changes to the overall mold design.
4Reliability
If two separate lids are required to form mass and spring, then both components can be formed, but multiple sets of molds are required for high volume production increasing costs
Solution Approach 1:
A single mold cavity serves multiple functions: it forms the mass layer first, then forms the spring layer on top of it, and can be reused indefinitely for high-volume production without requiring additional lids or mold sets. This multi-functionality eliminates the need for multiple specialized mold sets.
Solution Approach 2:
The formation process is segmented into sequential steps (mass layer then spring layer) within the same mold cavity, allowing the mold to handle multiple formation operations without requiring physical duplication of the mold structure for each operation.
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 reduces tooling costs and enables flexible sound attenuation adjustments, optimizing material usage and production efficiency for high-volume manufacturing by tailoring acoustic properties to specific sound profiles.
Implementation Method 1
The thermoplastic sheet may be at least one of vacuum-formed and thermo-formed
Implementation Method 2
The thermoplastic sheet may be at least one of vacuum-formed and thermo-formed
Implementation Method 3
the second acoustic mass layer composition spray formed in place on the backside of the first acoustic mass layer may be formed in place from reactive components which react to form a thermoset polymer
Implementation Method 4
The second acoustic mass layer may comprise a composition which is spray formed in place on the backside of the first acoustic mass layer
Data Source
AI summary
An acoustic insulator for a motor vehicle is provided comprising a mass providing an acoustic barrier and a spring providing an acoustic absorber overlying the mass. The mass comprises a first acoustic mass layer underlying a second acoustic mass layer. The first acoustic mass layer is provided by a thermoplastic sheet having a thickness in a range of 0.5 mm to 1 mm. The second acoustic mass layer is provided at one or more localized areas formed in place on a backside surface of the first acoustic mass layer to increase an overall thickness of the mass at the one or more localized areas. The spring layer is formed in place on a backside of the second acoustic mass layer and the backside of the first acoustic mass layer.