Additive Manufacturing Stress Control via Magnetic Compensation
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Solution Overview
Problem
Additive layer manufacturing (ALM) processes, such as Laser Blown Powder, face challenges with stress buildup and distortion in components due to intense localized heating, leading to residual compressive stresses that cause buckling distortion, especially in thin section materials, and existing stress relief methods lack real-time monitoring and control.
Innovation Solution
A method and apparatus that incorporate stress measurement and real-time monitoring using strain measurement devices and load cells to clamp and measure stresses during the ALM process, allowing for informed stress relief through cold working or annealing while the component is still mounted, preventing distortion and reducing post-build treatment needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heavy clamping is used to prevent distortion during ALM build process, then manufacturing precision is improved, but device complexity and safety risks increase due to heavy clamp structure and stored energy release
Solution Approach 1:
The patent replaces heavy mechanical clamping structures with a magnetic field-based active compensation system. Magnets mounted on the build plate generate magnetic forces that actively counteract distortion forces in real-time, eliminating the need for heavy mechanical clamps and their associated safety risks while maintaining manufacturing precision
Solution Approach 2:
The work piece itself becomes part of the compensation system by incorporating magnets directly onto it. These magnets interact with the build plate magnets to create self-balancing forces that automatically compensate for distortion as it occurs during the additive manufacturing process
2Manufacturing precision
If stress measurement and real-time monitoring are implemented during ALM process, then manufacturing precision is improved through controlled stress relief, but device complexity increases due to additional sensors and control systems
Solution Approach 1:
The patent incorporates strain measurement devices and load cells that continuously monitor stress levels in the work piece during the ALM process. This real-time feedback is used to adjust manufacturing parameters and activate magnetic compensation forces when distortion thresholds are approached, enabling closed-loop control of stress and distortion
Solution Approach 2:
The system takes preliminary action by detecting stress buildup early through sensors and activating compensation measures before significant distortion occurs. The magnetic compensation system is engaged proactively based on sensor readings, preventing distortion rather than correcting it after the fact
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 enables precise control of stress levels and distortion, allowing for safer and more efficient manufacturing, reducing labor and post-build treatment costs, and improving component quality by ensuring the component is stress-relieved to predetermined levels during the build process.
Implementation Method 1
uses a powerful heat source such as a laser beam or a welding arc to melt a controlled amount of metal in the form of metallic powder or wire
Implementation Method 2
The laser is then scanned over the work piece along a path which defines the shape of the component to be manufactured. Powder is melted to this shape
Implementation Method 3
uses a known welding arc to melt additive layer material in the form of a wire
Implementation Method 4
The powder is carried to the focal point of the laser in a precisely directed carrier gas such as Argon
Implementation Method 5
If transverse compressive stresses in the work piece, which are caused by very hot expanding material, exceed the yield point of the material then compressive plastic yielding (CPY) will occur
Implementation Method 6
On cooling and shrinkage of the work piece, high tensile residual transverse stresses will be created across the weld
Implementation Method 7
A method and apparatus that incorporate stress measurement and real-time monitoring using strain measurement devices and load cells to clamp and measure stresses during the ALM process
Implementation Method 8
allowing for informed stress relief through cold working or annealing while the component is still mounted
Implementation Method 9
allowing for informed stress relief through cold working or annealing while the component is still mounted
Data Source
Figure 1~2
Figure 3
AI summary
Apparatus and a method for forming a metallic component by additive layer manufacturing are provided. The method includes the steps of mounting a work piece (3) to ALM manufacturing apparatus including measuring means in the form of load cells (13, 14) to measure stresses tending to distort the work piece, using a laser heat source (24) to apply heat to a surface (18) of the work piece (3) sufficient to melt it;adding metallic material to the melted surface (18) and moving the heat source (24) relative to the work piece (3) whereby progressively to form a layer (30) of metallic material on it; repeating the above steps as required, whereby progressively to form the component and, while doing so, measuring stresses tending to distort the component with the load cells (13, 14) and, if they are above a predetermined threshold, stress relieving the work piece with means such as a pulsed laser (27) while still mounted to the apparatus to reduce distortion to a predetermined level, and again repeating above steps as required to complete the component. A computer (16) may be included to control the whole process.