Additive Metal Layer Processing With a Rotating Friction Pin
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Solution Overview
Problem
In additive production methods like 3D printing for aircraft or spacecraft components, significant thermal input during layer deposition can lead to grain growth in metal materials, reducing mechanical strength, and existing methods such as rolling are complex and inefficient.
Innovation Solution
A method involving a rotating friction pin that introduces shear stresses and dislocations into the metal layers, preventing grain growth and improving mechanical strength by distributing heat effectively, with the pin being pressed onto the outer surface and moved along the entire surface to achieve uniform stress introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal input is applied to deposit metal layers in additive production, then material bonding and layer formation are achieved, but grain growth occurs in the crystal structure reducing mechanical strength
Solution Approach 1:
The friction pin is applied to the previously deposited layer before the next layer is deposited. This preliminary mechanical action introduces dislocations and shear stresses that refine the crystal structure in advance, preparing it to resist subsequent thermal exposure and prevent grain growth during the next layer's thermal input.
Solution Approach 2:
The thermal input that causes harmful grain growth is converted into a beneficial process by first applying mechanical shear stresses through the friction pin. The thermal energy that would otherwise coarsen the grain structure is instead utilized to anneal and stabilize the dislocation structures introduced by friction, transforming the harmful thermal effect into a beneficial heat treatment that enhances strength.
2Strength
If rolling is used to introduce shear stresses into component layers, then mechanical properties are improved, but the number of operating steps increases and production efficiency decreases
Solution Approach 1:
The invention extracts only the essential function of rolling (introducing shear stresses) while eliminating its complex multi-step operation. The friction pin concentrates the shear stress introduction into a single, simple passing motion, removing unnecessary rolling passes and complex positioning steps while maintaining the grain refinement effect.
Solution Approach 2:
Instead of using traditional rolling that applies compressive forces through large rollers, the invention inverts the approach by using a small friction pin that applies intense localized shear stresses through friction. This inverted approach achieves the same grain refinement effect with a simpler, faster single-pass operation rather than multiple rolling passes.
3Strength
If multiple passes are used to introduce sufficient shear stresses into the component layer, then dislocation density increases improving strength, but the processing time and operational complexity increase
Solution Approach 1:
The friction pin applies a high concentration of shear stresses in a single preliminary pass, creating sufficient dislocation density before subsequent layers are deposited. This preliminary action eliminates the need for multiple repeated passes, as the dislocations introduced are preserved and utilized by subsequent thermal cycles to maintain strength without requiring re-processing.
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 enhances mechanical strength by inhibiting grain growth, allowing for faster and more homogeneous solidification of layers with reduced complexity and increased production speed, while also simplifying the process by reducing the number of operating steps and enabling automatic guidance.
Implementation Method 1
introducing shear stresses and consequently imperfections or dislocations into the component layer produced in step a) by means of a friction pin which rotates about a rotation axis and which is pressed with a predetermined force on an outer surface of the component layer
Implementation Method 2
The dislocations facilitate a distribution of the heat introduced in the component layer and inhibit the grain growth of the metal material resulting from the thermal input
Data Source
AI summary
A method for producing a component is disclosed. In a first step, a planar component layer is produced on a base surface from a metal material which is above the melting temperature thereof. In a second step, shear stresses are introduced into the component layer produced in the first step by a friction pin which rotates about a rotation axis and which is pressed with a predetermined force onto an outer surface of the component layer opposite the base surface and which is moved along the entire outer surface of the component layer. Finally, in a third step, the first step is repeated on the outer surface as a base surface.