Microcellular Polyurethane Component Densification
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Solution Overview
Problem
Current methods for forming microcellular polyurethane components face challenges in creating thin and complex shapes, as well as achieving varying densities, particularly with thermosetting materials, which are difficult to deform without degrading.
Innovation Solution
A method involving heating and compressing specific portions of a microcellular polyurethane component to permanently increase the density of one portion relative to another, allowing for strategic densification and shaping of thin and complex forms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the liquid reaction mixture is used to form thin and complexly shaped MCU components, then the component can achieve desired size and shape, but the viscous reaction mixture does not easily flow into and fill thin and complexly shaped reaction molds
Solution Approach 1:
The component is formed in a partially cured gelled state first, allowing the viscous reaction mixture to be injected and held in place before complete curing. This preliminary formation step enables thin and complex shapes to be achieved by establishing the geometry early when the material is still pliable but sufficiently set to maintain the shape.
Solution Approach 2:
The curing state of the MCU is controlled as a variable parameter, transitioning from liquid reaction mixture to partially cured gelled state to fully cured solid. By manipulating the degree of curing during the forming process, the material exhibits optimal flow characteristics for injection followed by shape retention for complex geometries.
2Shape
If thermosetting material like MCU is heated to deform it, then the component can be shaped, but the thermosetting material cannot melt without degrading because the melt temperature is higher than the chemical degradation temperature
Solution Approach 1:
The component is formed and partially cured before attempting any deformation. This preliminary formation establishes the base geometry and ensures the material is in an optimal state for subsequent localized heating and densification without degrading the overall structural integrity.
Solution Approach 2:
Deformation through heating and compression is applied locally to specific portions of the component rather than uniformly across the entire part. This localized treatment allows shaping and density modification in targeted areas while maintaining the original properties in other regions, avoiding global degradation.
3Ease of manufacture
If the component is formed with uniform density, then the manufacturing process is simpler, but backings or skeletons having different density must be attached to achieve varying density
Solution Approach 1:
The densification process applies different treatment to different portions of the component, creating regions of varying density within a single homogeneous material structure. This eliminates the need to attach separate backings or skeletons while achieving the desired multi-density configuration.
Solution Approach 2:
The formation of varying density regions is merged into the single-step curing process of the homogeneous MCU material. Instead of separately forming high-density backings and low-density foam and then assembling them, the entire component is formed in one process with localized densification achieved through targeted heating and compression.
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
Enables the creation of components with varying densities and complex shapes, improving their durability and functionality, such as in coil spring isolators and jounce bumpers, by permanently deforming the cell walls of the microcellular polyurethane material.
Implementation Method 1
heating at least a first portion of the component to a first temperature
Implementation Method 2
compressing the first portion of the component while maintaining the first portion of the component at the first temperature
Data Source
AI summary
A method of deforming a component includes the step of forming the component from thermosetting, elastomeric microcellular polyurethane. The method further includes the step of heating at least a first portion of the component to a first temperature. The method further includes the step of compressing the first portion of the component while maintaining the first portion at the first temperature and while maintaining the second portion of the component at an undeformable state. The method of deforming the component shapes the first portion of the component. Preferably the method shapes the first portion of the component into a thin and/or complexly shape. The method of deforming the component also increases the first portion of the component relative to the second portion of the component, i.e. to densifying the component such that the component has varying density.