Weld Bead Monitoring for Defect Estimation in Additive Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing techniques for determining welding quality, such as those in Patent Literatures 1 and 2, are not applicable to additive manufacturing as they rely on a well-ordered base with walls supporting from both sides like a bevel, whereas additive manufacturing uses a heat source to form weld beads on existing weld beads, making defect estimation challenging.
Innovation Solution
An additive-manufacturing process monitoring device that includes a shape profile acquisition unit, a welding information acquisition unit, and a defect candidate extraction unit to estimate defects by determining angle and welding characteristic portions based on shape and welding information, associating them to identify potential defects in overlapping weld beads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing welding quality determination techniques are applied to additive manufacturing, then welding quality can be determined using standardized base structures, but these techniques cannot be applied because additive manufacturing uses existing weld beads as base instead of well-ordered base with supporting walls
Solution Approach 1:
The invention changes the parameters used for quality determination from those suitable for well-ordered bases with supporting walls to parameters appropriate for additive manufacturing conditions. Specifically, it uses shape profiles along the extension direction of existing weld beads and base angles instead of cross-sectional shapes of weld beads on prepared bases, making the technique adaptable to additive manufacturing's unique base structure
Solution Approach 2:
Instead of preparing a well-ordered base with supporting walls before welding (traditional approach), the invention inverts the approach by using the existing weld bead itself as the base for the next weld bead, and develops quality determination methods that work with this inverted manufacturing sequence
2Measurement precision
If multiple visual sensors are used to acquire welding information, then welding quality can be determined, but defect estimation reliability is insufficient in additive manufacturing due to heat accumulation and repeated weld bead formation
Solution Approach 1:
The invention performs preliminary acquisition of the shape profile along the extension direction of the existing weld bead before forming the adjacent weld bead. This preliminary action allows the system to identify angle characteristic portions in advance and associate them with welding characteristic portions during subsequent welding, improving defect estimation reliability in the challenging additive manufacturing environment
Solution Approach 2:
The invention establishes a feedback mechanism where the shape profile of the existing weld bead is acquired and analyzed to identify angle characteristic portions, which are then associated with welding characteristic portions during adjacent weld bead formation. This feedback loop enables continuous monitoring and reliable defect estimation throughout the additive manufacturing process
3Productivity
If weld beads are repeatedly laminated to build additively manufactured object, then the object can be constructed layer by layer, but heat accumulates and makes defect detection difficult
Solution Approach 1:
The invention performs preliminary acquisition of shape profiles and identification of angle characteristic portions before adjacent weld beads are formed. This allows defect candidates to be identified proactively during the construction process rather than requiring post-processing inspection, maintaining high construction speed while improving defect detection capability
Solution Approach 2:
The invention replaces complex mechanical inspection systems with a monitoring approach that uses shape profile acquisition and characteristic portion association. By substituting physical inspection mechanisms with analytical methods based on geometric and welding parameter analysis, the system achieves reliable defect detection without slowing down the rapid layer-by-layer construction process
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
The solution allows for reliable estimation of defects in additively manufactured objects, enabling quick identification and repair of potential issues without complex inspections.
Implementation Method 1
forming a plurality of weld beads in which a filler material is melted and solidified by a torch
Implementation Method 2
forming a plurality of weld beads in which a filler material is melted and solidified by a torch
Implementation Method 3
a shape profile acquisition unit for acquiring a shape profile along an extension direction of an existing weld bead
Implementation Method 4
determining an angle characteristic portion having a base angle equal to or greater than a threshold in the existing weld bead based on the shape profile, determining a welding characteristic portion of the welding information based on the welding information, and extracting the welding characteristic portion corresponding to the angle characteristic portion as a defect candidate by associating the welding characteristic portion with the angle characteristic portion
Data Source
AI summary
A shape sensor is provided for acquiring a shape profile along an extension direction of an existing weld bead, and a control unit includes a welding information acquisition unit for acquiring welding information during formation of an adjacent weld bead when forming the adjacent weld bead at a position adjacent to the existing weld bead, and a defect candidate extraction unit for determining an angle characteristic portion having a base angle equal to or greater than a threshold in the existing weld bead based on the shape profile, determining a welding characteristic portion of the welding information based on the welding information, and extracting the welding characteristic portion corresponding to the angle characteristic portion as a defect candidate by associating the welding characteristic portion with the angle characteristic portion.