Additive Mold Segment Design for Tire Tread Surface Quality
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Solution Overview
Problem
Additive manufacturing of mold segment components for pneumatic vehicle tires results in irregular tread surfaces due to layer-by-layer application of metal powder, leading to step formations that are difficult to smooth, resulting in an irregularly structured and less visually appealing vulcanized tire surface.
Innovation Solution
Mold area elements are built up as unitary planar surface areas or multiple planar surface areas with stepped differences, running parallel to each other, to approximate the curvature of the tread outer surface, eliminating the need for subsequent machining and enhancing the visual appeal of the vulcanized tire surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additive manufacturing is used to produce mold segment components, then manufacturing complexity is reduced and productivity is improved, but the tread surface becomes irregular with step formations
Solution Approach 1:
The patent applies preliminary action by designing mold area elements with built-in compensation for the layer-by-layer additive manufacturing process. The mold elements are pre-configured with specific geometries that account for the expected step formations, allowing the final tread surface to achieve the desired smooth curvature despite the additive manufacturing process. This is accomplished by offsetting the mold surface from the building plate surface and incorporating compensation values in the design phase.
Solution Approach 2:
The patent utilizes parameter changes by modifying the geometric parameters of the mold area elements to compensate for the layer thickness effects. By adjusting parameters such as the offset distance, layer thickness, and element geometry, the invention transforms the inherent roughness from additive manufacturing into a controlled feature that produces the desired smooth tread surface after vulcanization.
2Manufacturing precision
If subsequent machining is performed to smooth the tread surface, then surface quality is improved, but manufacturing complexity and time increase
Solution Approach 1:
The patent extracts the smoothing function from the post-manufacturing stage and integrates it into the mold design phase. By incorporating compensation features directly into the additive-manufactured mold elements, the need for subsequent machining operations is eliminated. The smoothing effect is achieved through the design of the mold area elements themselves, which are configured to produce the desired surface quality without requiring additional processing steps.
3Ease of manufacture
If layer-by-layer application of metal powder is used, then additive manufacturing capability is achieved, but step formations and irregular surfaces are created
Solution Approach 1:
The patent applies preliminary action by pre-compensating for the layer-by-layer manufacturing effects in the design of mold area elements. The offset between the building plate surface and the mold surface is calculated and incorporated into the design, along with compensation values that account for the expected step formations. This preliminary compensation ensures that the final tread surface achieves the desired smooth curvature despite the inherent layering of the additive process.
Solution Approach 2:
The patent utilizes curvature principles by designing the mold area elements to follow the desired curvature of the tread surface. The elements are configured with smooth curved geometries that, when combined with the offset compensation, produce the intended spherical or curved tread profile. This approach transforms the discrete layered structure into an effective continuous curved surface on the vulcanized tire.
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 solution results in qualitatively perfect positive surface areas on vulcanized tires, improving winter performance and grip on snow and ice by creating effective interlock effects, with enhanced edge pressure and microstructures for improved traction.
Implementation Method 1
additive process, such as selective laser melting, by layer-by-layer planar application and melting of a metal powder on a planar building plate
Data Source
AI summary
A method for producing a mold segment component of a vulcanizing mold for a pneumatic vehicle tire for forming at least one profile block or a region structured in a block-like manner of an altogether curved tread, with a tread outer surface, which mold segment component is built up by means of an additive process, such as selective laser melting, by layer-by-layer planar application and melting of a metal powder on a planar building plate (10) together with a bottom part (7b) and mold elements, such as lamellae (4) and/or microlamellae (11) and/or ribs and/or regions of ribs, wherein mold elements delimit or run around mutually adjacent mold area elements (12) of the bottom part (7b) which have outer surfaces (12a) forming a region of the tread outer surface.In the additive build-up operation, the mold area elements (12) are each additively built up with a unitary planar outer surface (12a) or with two to three planar outer surfaces (12a) running in a stepped manner in relation to one another, wherein all of the outer surfaces (12a) of the mold area elements (12) run parallel to one another and, with respect to the building plate (10), are surfaces at different levels such that the mutual arrangement of the outer surfaces (12a) of the mold area elements (12) largely approximates to the curvature of the region to be formed of the tread outer surface.