Additive Manufacturing Gas Atmosphere Control to Prevent Pores
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Solution Overview
Problem
Pores form in workpieces produced by additive manufacturing due to oxygen infiltration and increased water vapor content in the gas atmosphere, leading to metallurgical defects.
Innovation Solution
A method where the gas atmosphere in the manufacturing chamber is continuously monitored and controlled by extracting a gas stream, determining its parameters, and replacing it with a process gas, such as inert argon, to maintain stable conditions and prevent oxygen and water vapor from exceeding predefined nominal values, ensuring isotropic and homogeneous gas composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas atmosphere is provided in the manufacturing chamber during laser melting, then metallurgical properties of the workpiece can be influenced, but oxygen infiltration and increased water vapor content lead to pore formation
Solution Approach 1:
The patent implements a feedback control system where the gas atmosphere composition is continuously monitored and adjusted. The gas composition is determined before and after recirculation, and the flow rate is controlled based on comparing these compositions to maintain optimal conditions and prevent pore formation
Solution Approach 2:
The patent uses an inert gas atmosphere (such as argon) in the manufacturing chamber to prevent oxidation and harmful reactions with the metallic material during laser melting. The inert gas is recirculated through a controlled flow system to maintain protective atmosphere conditions
2Loss of energy
If the gas atmosphere is recirculated to maintain stable conditions, then energy efficiency improves, but oxygen and water vapor accumulate leading to degraded gas composition
Solution Approach 1:
The system determines the gas composition before and after recirculation and uses this feedback information to control the flow rate of inert gas through the manufacturing chamber, maintaining stable composition by adjusting recirculation parameters
Solution Approach 2:
The patent dynamically adjusts the flow rate parameter of the inert gas based on measured composition changes, balancing energy efficiency through recirculation with maintaining gas composition stability by introducing fresh gas when degradation is detected
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 prevents the formation of pores, enhances the quality of workpieces by maintaining consistent metallurgical properties, and allows for cost-effective production with minimal effort, eliminating the need for subsequent processing to remove pores.
Implementation Method 1
acted upon with a laser beam and/or electron beam. In this way, the material can be subjected to a sintering or melting process
Implementation Method 2
If inert gases are chosen for the gas atmosphere, no reaction with the metallic material takes place
Data Source
AI summary
There is provided a method for producing a metallic workpiece in layers by additive manufacturing, metallurgical layers of the workpiece being produced by providing a metal material in a manufacturing chamber for each metallurgical layer and applying a laser beam to the metal material, and providing a gas atmosphere in the manufacturing chamber during the application of the laser beam to the layers of the metal material, wherein a part of the gas atmosphere is drawn off from the manufacturing chamber as a gas stream, at least one parameter of the gas stream and/or the gas atmosphere being determined and being compared with a desired value. Depending on the comparison of the parameter with the desired value, the gas stream is fed back to the manufacturing chamber and a process gas is supplied to the manufacturing chamber.