Weld Bead Deposition Planning for Defect-Free Intersection Layers
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Solution Overview
Problem
Existing methods for forming additively manufactured objects using weld beads face issues with internal defects at intersection portions due to gaps between overlapping weld beads, requiring complex tuning of welding conditions.
Innovation Solution
A deposition planning method that classifies welding paths into intersection and constant regions, adjusts welding rates and deposit amounts to ensure uniform bead height, and sets conditions to prevent gaps by overlapping weld beads in cross-sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding conditions are adjusted to prevent gaps between weld beads at intersection portions, then internal defects are suppressed, but the setting of welding conditions becomes complex requiring many tuning parameters
Solution Approach 1:
The welding path is segmented into two distinct types: intersection region paths and constant region paths. This segmentation allows different welding conditions to be applied to different regions, simplifying the overall control by reducing the number of independent tuning parameters while maintaining reliability at critical intersection portions.
Solution Approach 2:
Different welding conditions are applied locally to different regions: intersection region paths use conditions optimized for preventing gaps and internal defects, while constant region paths use standard conditions. This local differentiation ensures high reliability at intersection portions without requiring complex global parameter tuning.
2Manufacturing precision
If welding conditions are changed at intersection points to prevent contour distortion, then the amount of metallic material welded to the intersection point is controlled, but the setting of welding conditions becomes complicated requiring enormous effort
Solution Approach 1:
The welding path is divided into intersection region paths and constant region paths, with distinct welding conditions for each. This segmentation automates the control of metallic material amount at intersection points without requiring complex manual tuning, as the system automatically applies appropriate conditions to each path type.
Solution Approach 2:
Welding conditions (such as welding speed, wire feed rate, or heat input) are specifically changed for intersection region paths compared to constant region paths. This parameter differentiation enables precise control of metallic material amount at intersection points while simplifying the overall process through automated parameter selection based on path type.
3Shape
If weld beads are formed by stopping before previously formed beads and restarting after them, then intersection portions are formed, but gaps are created between end edge and start edge of weld beads leading to internal defects
Solution Approach 1:
The welding path is segmented into intersection region paths where weld beads overlap to form continuous material at intersection portions, eliminating gaps. This segmentation allows the system to maintain both the desired intersection shape and reliability by using continuous welding along the intersection region path rather than stopping and restarting.
Solution Approach 2:
Welding is performed continuously along the intersection region path without stopping before or after previously formed beads. This continuous action ensures that weld beads overlap properly at intersection portions, eliminating gaps and preventing internal defects while maintaining the required intersection shape.
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
Prevents internal defects and ensures uniform deposition height by overlapping weld beads at intersection portions, simplifying the setting of welding conditions.
Implementation Method 1
an additive manufacturing apparatus that deposits weld beads obtained by melting and solidifying a filler metal
Implementation Method 2
melting a metal powder and a metal wire using a laser, an electron beam, or a heat source such as an arc and depositing the molten metal
Data Source
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AI summary
A deposition planning method for an additively manufactured object includes: a step of acquiring shape data; a step of determining a welding path of each layer by slicing a three-dimensional shape of the additively manufactured object into layers; a step of classifying a plurality of welding paths into intersection region paths and constant region paths; a step of dividing the intersection region paths into a lower layer path and an upper layer path of an intersection portion; and a step of determining welding conditions of the intersection region paths such that an upper layer deposit amount is more than a lower layer deposit amount, a sum of the upper layer deposit amount and the lower layer deposit amount is equal to a deposit amount in the constant region paths, and in a cross-section orthogonal to a longitudinal direction of the weld beads formed along the upper layer path, profiles of the weld beads adjacent to each other overlap each other.