Weld Bead Deposition Control for Height Deviations in Metal AM
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Solution Overview
Problem
Existing methods for additively manufacturing objects using metal 3D printers face challenges in stabilizing weld bead deposition, particularly at the starting and ending portions of layers, where height deviations are significant, making it difficult for normal feedback control to correct processing conditions in time.
Innovation Solution
A method that involves measuring the base height using a shape sensor, setting welding conditions based on planned heights, and updating correction ratios to stabilize weld bead deposition by selecting from pre-determined correction ratios tailored to specific shape characteristics and height deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If normal feedback control is used to measure base height and adjust welding conditions, then processing conditions can be corrected based on measurement results, but correction is not timely enough when local height deviations are large, causing unstable bead deposition
Solution Approach 1:
The system performs preliminary measurement of the base height at the deposition position before actual welding begins. This advance measurement allows the control system to calculate the required height correction and adjust welding parameters (such as deposition amount or torch height) before the welding process starts, ensuring timely correction without delaying the overall process.
Solution Approach 2:
The control system dynamically adjusts welding parameters based on real-time base height measurements. When a large height deviation is detected, the system automatically modifies deposition conditions (such as increasing deposition amount or adjusting torch trajectory) to compensate for the deviation, enabling adaptive correction that responds to actual conditions rather than using fixed parameters.
2Adaptability or versatility
If feedback control with single correction ratio is used, then processing conditions can be adjusted, but it cannot adapt to different shape characteristics and height deviation magnitudes, reducing manufacturing precision
Solution Approach 1:
The system employs multiple correction ratios corresponding to different magnitude ranges of height deviations. When a height deviation is detected, the control system determines the deviation magnitude and selects the appropriate correction ratio from the plurality of available ratios. This allows the system to adaptively adjust welding parameters with the appropriate level of correction for each specific situation, improving both adaptability and precision.
Solution Approach 2:
The control system applies different correction strategies to different regions based on local characteristics. By dividing the correction approach into multiple ratios tailored to different deviation magnitudes and potentially different spatial regions (such as starting/ending portions versus middle portions of beads), the system provides locally optimized correction that accounts for the specific conditions at each location.
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 stable formation of weld beads across varying height deviations, ensuring consistent deposition and improving the quality of additively manufactured objects by adapting welding conditions in real-time.
Implementation Method 1
a base measurement processing of acquiring a measured height by measuring, using a shape sensor, a height of a base at a position where the torch is to be moved when depositing the weld beads
Implementation Method 2
weld beads obtained by melting and solidifying a filler material is deposited with a torch while moving the torch to build a built object
Data Source
AI summary
In a building step, a base measurement processing of acquiring a measured height by measuring, using a shape sensor, a height of a base at a position where a torch is to be moved when depositing weld beads; a welding condition setting processing of obtaining a planned height of the base at the position where the torch is to be moved from a deposition plan, comparing the measured height acquired in the base measurement processing and the planned height to obtain a differential height, and setting a welding condition in a feedback correction for reducing the differential height; and a correction ratio update processing of performing a selection from a plurality of correction ratios set in advance and updating a correction ratio in the welding condition based on a selected correction ratio are executed.