Weld Bead Trajectory Control for Fatigue-Resistant 3D Printing
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Solution Overview
Problem
Additive manufacturing methods using weld beads result in surface unevenness, particularly on inner surfaces, leading to stress concentration and reduced fatigue strength due to the inability to smooth these areas with tools.
Innovation Solution
An additive manufacturing support device and method that determine the bead forming trajectory by analyzing the shape model and load conditions to minimize stress concentration, using a control unit to adjust the weld bead formation direction based on maximum principal stress directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If weld bead deposition is used to manufacture three-dimensional objects, then manufacturing flexibility and complexity are improved, but surface unevenness occurs leading to stress concentration and reduced fatigue strength
Solution Approach 1:
The patent applies preliminary action by performing stress analysis and determining optimal bead forming trajectories before the actual additive manufacturing process. The trajectory determination unit calculates the maximum principal stress direction and sets the bead forming trajectory in advance to align with stress directions, preventing stress concentration before it occurs. This proactive approach ensures that the manufactured object achieves desired fatigue strength without requiring post-processing corrections.
2Ease of manufacture
If conventional bead deposition trajectory is used, then manufacturing process is simple, but stress concentration occurs due to surface unevenness on inner surfaces
Solution Approach 1:
The patent implements feedback by using stress analysis results to continuously optimize the bead forming trajectory. The trajectory determination unit receives feedback from the maximum principal stress direction calculation and adjusts the deposition path accordingly. This closed-loop approach ensures that each weld bead is deposited in the optimal position to minimize stress concentration, improving surface uniformity while maintaining manufacturing efficiency through automated trajectory calculation.
3Manufacturing precision
If post-processing is applied to smooth outer surfaces, then surface unevenness is reduced, but inner surface unevenness cannot be addressed due to tool access limitations
Solution Approach 1:
The patent eliminates the need for post-processing by performing preliminary optimization during the manufacturing phase itself. The trajectory determination unit calculates optimal bead formation paths that prevent stress concentration from occurring in the first place, particularly in inner surfaces that would be inaccessible to post-processing tools. This approach ensures both outer and inner surfaces achieve desired quality without requiring subsequent machining or smoothing operations.
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 suppresses stress concentration and enhances fatigue strength by optimizing the weld bead formation trajectory, ensuring the fatigue limit meets or exceeds design requirements.
Implementation Method 1
a welding wire is melted and solidified by arc discharge to form a weld bead
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An additive manufacturing support device includes a building condition acquisition unit configured to acquire information on a shape model of an object and a load condition applied to the object; a stress analysis unit configured to determine a maximum principal stress direction generated in each portion of the object, by stress analysis based on the acquired shape model and load condition; and a trajectory determination unit configured to determine a forming direction of a weld bead on the basis of the maximum principal stress direction and the load condition.