Automotive Foaming Process Mould Expansion for Density Reduction
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Solution Overview
Problem
Traditional foaming processes result in higher densities, heavier weights, and increased costs due to fixed mould positions and inefficient material expansion, which are not addressed by existing methods that incorporate premanufactured plastic skeletons in automotive interiors.
Innovation Solution
A lightweight foaming process involving a mould expansion sequence where a foaming material is injected into a closed mould, allowed to react and expand, and then the mould is opened to a larger position, enabling the material to fill and expand further, reducing density by utilizing gas expansion within the cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the mould is kept in a fixed position during foaming, then the process is stable and simple to control, but the foamed layer density is high (160-180 g/L) and the weight is heavy
Solution Approach 1:
The patent applies the dynamics principle by transforming the mould from a fixed position to a movable position during the foaming process. The mould is moved from a first position during material injection to a second position after injection, allowing the foaming material to expand into additional space. This dynamic adjustment enables the same amount of foaming material to occupy a larger volume, thereby reducing density from 160-180 g/L to below 100 g/L and reducing weight by more than 30%, while maintaining process stability through controlled movement sequences.
2Weight of moving object
If the mould cavity thickness is increased to reduce density, then the foamed layer becomes lighter, but the material expansion efficiency decreases and more material is needed
Solution Approach 1:
The patent applies the dimensionality change principle by utilizing the mould movement in space to create additional expansion volume. Instead of simply increasing the initial mould cavity thickness, the system moves the mould from a first position to a second position, effectively adding spatial dimension to the expansion process. This allows the foaming material to expand into the newly created space, achieving lower density and reduced material quantity requirements without compromising expansion efficiency.
3Volume of stationary object
If a two-step injection moulding process is used to create space for foaming, then the mould cavity can be enlarged, but the process complexity increases and production time is extended
Solution Approach 1:
The patent applies the merging principle by combining the injection and foaming operations into a single continuous process. Unlike the two-step injection moulding process that requires separate operations, this patent injects the foaming material directly into the mould and then moves the mould to enable expansion, merging multiple functions into one integrated process flow. This reduces process complexity while achieving the same volume expansion effect, and eliminates the need for separate injection and foaming cycles.
4Ease of operation
If the foaming material is allowed to expand freely without mould movement, then the expansion process is simple to control, but the central porosity is insufficient and density remains high
Solution Approach 1:
The patent applies the periodic action principle by implementing a two-stage mould movement sequence: first, the mould remains stationary during material injection; second, after injection is complete, the mould moves to a second position to enable continued expansion. This periodic alternation between stationary and moving states allows the foaming material to first fill the initial cavity uniformly, then expand into additional space with proper porosity distribution, achieving both ease of operation and manufacturing precision.
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 process reduces the density of the foamed layer by approximately 20% under the same thickness, leading to lighter, cheaper components with reduced material usage and environmental impact.
Implementation Method 1
injecting a foaming material into the first mould cavity space; waiting for the foaming material to react and expand within the first mould cavity
Implementation Method 2
waiting for the foaming material to react and expand until the foaming material fills the first mould cavity space
Implementation Method 3
moving the mould upwardly to open the mould from the first predetermined position to a second predetermined position
Implementation Method 4
waiting for the foaming material to continue to expand and fill along a mould opening direction until the second mould cavity space is filled
Data Source
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AI summary
The present invention provides a lightweight foaming process, used for an automotive interior, which comprises following steps: S1, closing a mould to a first predetermined position to form a first mould cavity space; S2, injecting a foaming material into the first mould cavity space; S3, waiting for the foaming material to react and expand within the first mould cavity until the foaming material fills the first mould cavity space; S4, moving the mould upwardly to open the mould to a second predetermined position, wherein the first mould cavity space is enlarged to form a second mould cavity space; S5, waiting for the foaming material to continue to expand and fill along a mould opening direction until the second mould cavity space is filled; S6, opening the mould and removing a foamed member. The present invention can reduce the density of a foamed layer, thereby reducing the weight. The reduction of the weight can reduce the use of materials, thereby reducing costs. The reduction of the use of foaming material can also be more environmentally friendly.