Hybrid Additive Manufacturing with Deep Rolling
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Solution Overview
Problem
Conventional additive manufacturing techniques produce products with mechanical properties comparable to cast materials, often containing tensile residual stresses, surface roughness issues, and anisotropic microstructures, which hinder the binding of additional layers and weaken the product.
Innovation Solution
The method involves deep rolling of additive material layers to induce plasticity, reduce tensile residual stresses, and refine microstructures, using techniques like powder deposition and laser engineered net shaping, with deep rolling tools applying localized pressure to achieve compressive residual stresses and smooth surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional additive manufacturing techniques are used to produce complex geometries, then manufacturing capability for near net shaped products is improved, but mechanical properties remain comparable to cast materials rather than wrought materials
Solution Approach 1:
The patent applies post-processing parameters (heat treatment temperature, rolling pressure, layer orientation) to transform the microstructure and mechanical properties of additive manufactured parts. By changing these parameters, the material transitions from cast-like properties to wrought-like properties while maintaining the complex geometry capability
Solution Approach 2:
The patent creates a composite microstructure through controlled layering and post-processing treatments. The combination of additive manufactured layers with subsequent heat treatment and rolling processes produces a hybrid microstructure that achieves wrought material properties while retaining additive manufacturing geometric flexibility
2Shape
If conventional additive manufacturing is used to build layers, then complex geometries are achieved, but tensile residual stresses are present throughout the product
Solution Approach 1:
The patent applies preliminary heat treatment and rolling processes to counteract the tensile residual stresses generated during additive manufacturing. By applying compressive stresses through rolling and controlled cooling, the harmful tensile stresses are neutralized before final part completion
Solution Approach 2:
The patent utilizes thermal expansion and contraction during heat treatment cycles to relieve residual stresses. By controlling the heating and cooling rates, the material undergoes thermal cycles that redistribute and reduce tensile residual stresses while maintaining the desired complex geometry
3Ease of manufacture
If conventional additive manufacturing produces layers with oriented microstructure, then layer-by-layer construction is achieved, but product strength is weakened
Solution Approach 1:
The patent changes the microstructural parameters through heat treatment and mechanical rolling processes. By controlling grain size, orientation, and phase distribution through these parameters, the anisotropic layered microstructure is transformed into a more isotropic, refined microstructure that maintains strength
Solution Approach 2:
The patent segments the material into fine-grained structures through controlled cooling and rolling processes. This segmentation of the microstructure into smaller, uniformly distributed grains prevents the formation of large weak planes that would reduce overall product strength while preserving the additive manufacturing construction advantage
4Shape
If conventional additive manufacturing is used, then near net shaped products are produced, but surface roughness makes it difficult for additional layers to bind
Solution Approach 1:
The patent applies preliminary surface treatments (heat treatment, rolling, or machining) to each layer before the next layer is deposited. This preliminary action smooths the surface and activates the material surface, ensuring proper adhesion between layers while maintaining the near net shape capability
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 enhances the mechanical properties of additive manufactured products by reducing anisotropic microstructures, eliminating tensile stresses, and improving surface roughness, resulting in components with improved hardness and microstructural refinement.
Implementation Method 1
rolling the first layer of additive material to induce plasticity in the first layer of additive material
Implementation Method 2
Deep rolling at least one of the first and second layers of additive material may impart a residual stress to a depth of about 1 mm to about 1.5 mm
Implementation Method 3
the step of forming the layers of additive material on a substrate may include melting a metal powder, forming a melt pool of the melted metal powder on the substrate and allowing the melt pool to solidify
Implementation Method 4
melting a metal powder, forming a melt pool of the melted metal powder on the substrate and allowing the melt pool to solidify
Implementation Method 5
Deep rolling the at least one of the first and second layers of additive material may refine the microstructure of the layer
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
An additive manufacturing method for forming a component is disclosed. The method includes the steps of forming a first layer of additive material on a substrate. The first layer of additive material is deep rolled. A second layer of additive material is then formed on the first layer of additive material.