Bi-Material Cartesian Robot Link with Thermal Expansion Relief
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Solution Overview
Problem
Multi-axis Cartesian robots in the plastics industry face challenges with aluminum links, which are flexible and costly, while steel links are difficult to produce with complex shapes and integrating both materials leads to unacceptable deflection due to the bimetallic effect.
Innovation Solution
A bi-material link is created using a stiffening element made from a folded steel sheet and a holding/guiding element from an extruded aluminum profile, secured together with local deformations to allow temperature-induced expansion/contraction, minimizing the bimetallic effect and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aluminum links are used in Cartesian robots, then the links can be produced with complex shapes and integrated functions, but the links exhibit high flexibility and weakness leading to reduced reliability
Solution Approach 1:
The patent combines aluminum and steel materials in a bi-material link structure. The aluminum profile provides complex shape and integrated functions, while the steel stiffening element provides rigidity and strength. This composite approach resolves the contradiction by allowing complex manufacturing while ensuring structural reliability through the steel reinforcement.
2Reliability
If steel links are used in Cartesian robots, then the links provide high strength and rigidity, but the production of profiles with complex functions becomes difficult or impossible
Solution Approach 1:
The patent uses a bi-material construction where the aluminum profile carries the complex integrated functions and shape, while the steel stiffening element provides the necessary strength. This resolves the contradiction by assigning different functional roles to each material based on their properties.
Solution Approach 2:
The link is segmented into two distinct elements: an aluminum profile element and a steel stiffening element. Each segment is optimized for its specific function - the aluminum for complex shaping and integration, the steel for structural strength - and then combined to form the complete link.
3Adaptability or versatility
If bi-material assembly is used to combine aluminum and steel, then the bimetallic effect causes significant deflection under temperature gradient
Solution Approach 1:
The steel stiffening element is positioned specifically within the aluminum profile at strategic locations to provide local reinforcement. This localized approach allows the bi-material assembly to accommodate thermal expansion differences while maintaining overall structural stability and minimizing deflection.
Solution Approach 2:
The stiffening element is pre-positioned and secured within the aluminum profile to counteract the bimetallic effect before temperature gradients cause significant deflection. This preliminary structural arrangement prevents excessive thermal deformation.
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 stress and deflection in the link, providing a more reliable and cost-effective solution by allowing relative sliding of elements under temperature changes without compromising support functionality.
Implementation Method 1
at least one of said elements has a plurality of local deformations allowing expansion or contraction of one or more portions of one of said elements relative to the other, when the temperature varies
Data Source
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AI summary
The invention relates to a multi-axis Cartesian robot comprising at least one link (1, 1'). According to the invention, said link (1, 1') consists of at least two elements made of two different materials and joined together: - a stiffening element (2, 2'), made from a folded steel sheet; and - a support and/or guide element (3, 3'), made from an extruded aluminum profile. Furthermore, the stiffening element and the support and/or guide element are joined to each other by a fixed connection at constant temperature, and at least one of said elements (2, 2', 3, 3') has a plurality of local deformations (4, 4') allowing for the expansion or contraction of one or more portions of one of said elements relative to the other, when the temperature varies.