Elastomer Support Element Coating for Reproducible Fire Protection
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Solution Overview
Problem
The challenge lies in producing a fire protection coating for elastomer springs used in rail vehicles that meets specified fire protection standards, as existing methods struggle to combine different rubber mixtures and ensure consistent layer thicknesses, making the manufacturing process difficult and non-reproducible.
Innovation Solution
A method involving an injection molding process where a first elastomer mixture forms a shell with a surface structure, which is partially vulcanized to facilitate detachment, and a second mixture is injected to create the support body, allowing for a fire protection coating to be applied efficiently and reproducibly, with optional metal components and reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fire protection coating is applied to elastomer springs, then fire protection properties are improved, but manufacturing complexity increases due to difficulty in combining different rubber compounds and ensuring consistent layer thicknesses
Solution Approach 1:
The manufacturing process is segmented into two distinct injection molding steps: first forming the coating shell from the fire protection rubber compound, then forming the support body from the elastomer compound. This segmentation allows each material to be processed separately with optimized parameters, eliminating the complexity of combining different rubber compounds in a single step while ensuring consistent layer thicknesses through controlled cavity gap dimensions.
Solution Approach 2:
The coating shell is formed in advance as a preliminary structure before the support body is injected. The shell is partially vulcanized to achieve sufficient hardness for handling and core removal, yet remains flexible enough to accommodate subsequent processing. This preliminary action establishes the fire protection layer with controlled thickness before the main structural component is formed.
2Reliability
If different rubber compounds are combined for coating and support body, then fire protection and mechanical properties are improved, but manufacturing reproducibility deteriorates
Solution Approach 1:
The use of different rubber compounds is enabled by segmenting the injection process into two separate steps. Each compound can be independently formulated and processed with optimized curing conditions, eliminating the variability introduced by attempting to combine multiple compounds in a single injection step. The process parameters for each material are independently controlled and optimized.
Solution Approach 2:
Different physical and chemical parameters are applied to each injection step: the first injection uses parameters optimized for the fire protection rubber compound (temperature, pressure, curing time), while the second injection uses parameters optimized for the elastomer compound. This parameter differentiation allows each material to achieve its optimal properties while maintaining overall process reproducibility through standardized procedural control.
3Reliability
If the coating layer is formed with defined thickness, then fire protection effectiveness is improved, but process complexity increases due to need for precise gap control
Solution Approach 1:
The mold core is designed with a predetermined geometry that defines the cavity gap width, establishing the coating thickness in advance before the injection process begins. This preliminary geometric definition ensures consistent layer thickness through precise core manufacturing rather than relying on complex real-time control mechanisms during injection.
Solution Approach 2:
The coating thickness is controlled by fixing the geometric parameter of the cavity gap (determined by mold core dimensions) rather than by adjusting injection parameters. This transforms the thickness control problem from a dynamic process control challenge into a static geometric design parameter, simplifying the overall manufacturing process while ensuring consistent fire protection layer thickness.
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 method enables the production of high-quality, coated support elements with enhanced fire protection properties in an efficient and reproducible manner, ensuring adherence to fire protection standards while maintaining mechanical integrity.
Implementation Method 1
The first mixture is then vulcanized. This means the vulcanization process is initiated but not yet completed, so that at least the surface of the shell is hardened.
Implementation Method 2
a second mixture, in particular an elastomer mixture different from the first mixture, is injected into the cavity, preferably under pressure with the mold parts in the closed position. The second mixture is preferably plasticized and forms a support body
Data Source
Figure 1~2
AI summary
A method for producing a bearing element (3) coated with a coating (1) from elastomer material is shown and described, comprising the steps of: - providing an injection molding device (5) which, in a closed position, encloses a cavity (9) whose molded parts (7a, 7b, 7c) have an inner surface (4) provided with a surface structure (6); - inserting a mold core (11) into the cavity (9) so that a gap (13) remains, which corresponds to the shape of the coating (1) of the bearing element (3) to be produced; - inserting a first mixture (15) into the gap (13) so that the first mixture (15) fills the gap (13) and forms a shell (17) which has the shape of the coating (1), wherein the first mixture (15) also fills the surface structure (6); - vulcanizing the shell (17); - removing the mold core (11); - injecting a second mixture (19) into the cavity (9),so that it forms a support body (23) which rests against the inside of the shell (17), - vulcanizing the support body (23) together with the shell (17) so that they are joined together and the shell (17) forms the coating (1) of the support body (23).