Variable Thickness Extrusion Using an Adjustable Tapered Mandrel
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Solution Overview
Problem
Current metal extrusion techniques face challenges in producing components with varying mechanical properties along a length, such as achieving high strength in one region and high ductility in another, without introducing thermal non-uniformities and defects, and often require complex manufacturing steps like welding or variable cooling which can be difficult to reproduce.
Innovation Solution
The implementation of Shear Assisted Processing and Extrusion (ShAPE) using a tapered mandrel that adjusts its axial position relative to the extrusion die, allowing for modulation of the extrusion aperture without stopping the process, enabling the production of extrudate with varying inner diameters and wall thicknesses, which are then compressed to achieve uniform thickness and tailored mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional metal extrusion techniques are used to produce components with varying mechanical properties, then complex manufacturing steps like welding or variable cooling are required, but this increases device complexity and reduces reproducibility
Solution Approach 1:
The patent applies the dynamics principle by making the mandrel position adjustable during the extrusion process. The mandrel can be dynamically repositioned along the extrusion die to modulate the aperture size, enabling continuous variation of extrudate dimensions and mechanical properties within a single extrusion operation, thereby eliminating the need for multiple discrete manufacturing steps
Solution Approach 2:
The patent implements parameter changes by varying the mandrel axial position to modulate the extrusion aperture dimensions. This changes the physical parameters of the extrusion process in real-time, allowing production of extrudate with different inner diameters, wall thicknesses, and mechanical properties from a single feedstock without requiring complex post-processing or welding operations
2Strength
If the extrusion aperture is modulated to produce varying wall thicknesses, then different mechanical properties are achieved, but thermal non-uniformities and defects may be introduced
Solution Approach 1:
The patent applies preliminary action by pre-heating the feedstock to a uniform temperature before extrusion and maintaining controlled heating during the process. This preliminary thermal preparation ensures that even as the aperture is modulated to create variable wall thicknesses, the material remains at appropriate processing temperatures, preventing thermal non-uniformities and defects while achieving the desired mechanical properties
3Strength
If variable cooling is used to achieve different mechanical properties along the extrudate, then the process is difficult to reproduce, but consistency is required
Solution Approach 1:
The patent applies preliminary action by establishing uniform feedstock pre-heating and controlled extrusion conditions before the extrusion process begins. By controlling the thermal state and processing parameters in advance, the method eliminates the need for variable cooling, enabling consistent reproduction of extrudate with different mechanical properties through simple mandrel repositioning
Solution Approach 2:
The patent implements parameter changes by using mandrel position as the primary control variable to modulate aperture size and extrudate geometry. This single-parameter control method (mandrel axial position) replaces complex multi-parameter variable cooling systems, significantly improving reproducibility while achieving the desired mechanical properties distribution along the extrudate length
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 effectively creates regions with different mechanical properties along the extrudate length, enhancing ductility and tensile strength by up to 25% and 50% respectively, without the need for complex manufacturing steps, and improves the reproducibility of the extrusion process.
Implementation Method 1
The feedstock can deform plastically as it flows through the die opening, resulting in an extruded product with refined microstructure
Implementation Method 2
adjusting the axial position of the tapered mandrel modulates an extrusion aperture of the extrusion die
Implementation Method 3
The first and second portions can then be compressed, e.g., using a rolling mill, to reduce a thickness differential between the portions
Data Source
AI summary
A method for solid phase processing (SPP) of a feedstock is provided. The method can include providing relative rotation and translation between an extrusion die and a feedstock, where the die has an extrusion aperture through which a tapered mandrel extends. A first and second extrudate portions can each be generated via the aperture. An axial position of the tapered mandrel can be adjusted relative to the die face during the rotation and translation such that a second extrudate portion is generated having a different inner dimension compared to the first portion, thereby varying a wall thickness between portions.