Robotic Welding Height Error Compensation via CTWD Feedback
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Solution Overview
Problem
During robotic welding additive manufacturing, the actual height of weld layers often deviates from the expected height due to factors like surface conditions and parameter control accuracy, leading to inconsistencies in the workpiece part.
Innovation Solution
A system that samples welding output current and wire feed speed in real-time to determine instantaneous contact tip-to-work distances, calculates an average distance, and generates a correction factor to adjust weld duration or wire feed speed for subsequent layers, thereby compensating for height errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If real-time sampling and correction is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The system samples welding output current and wire feed speed in real-time during the additive manufacturing process, determines instantaneous contact tip-to-work distances, calculates average CTWD, and generates correction factors that are applied to subsequent layers. This closed-loop feedback mechanism continuously monitors and adjusts welding parameters to compensate for height deviations, thereby improving layer height accuracy and overall manufacturing precision.
Solution Approach 2:
The patent replaces direct mechanical measurement of contact tip-to-work distance with an electrical measurement approach. By sampling welding output current and wire feed speed and using these electrical parameters to determine CTWD indirectly, the system avoids complex mechanical measurement devices while achieving the same control objective.
2Manufacturing precision
If average CTWD calculation is performed, then manufacturing precision is improved, but loss of time occurs due to data processing
Solution Approach 1:
The system calculates the average contact tip-to-work distance based on multiple instantaneous CTWD measurements taken during the welding process. This preliminary calculation of average CTWD provides a representative value that captures the overall positioning accuracy, enabling timely correction factor generation without requiring analysis of every individual measurement point, thus balancing precision with processing efficiency.
3Manufacturing precision
If correction factors are generated for each layer, then manufacturing precision is improved, but productivity decreases due to additional processing steps
Solution Approach 1:
The system dynamically adjusts welding parameters by generating correction factors based on average CTWD calculations. These correction factors modify welding parameters such as wire feed speed or welding current for subsequent layers, enabling precise height control without requiring complete process redesign. The parameter adjustments are applied incrementally layer-by-layer, maintaining productivity while improving precision.
Data Source
AI summary
A system and method to correct for height error during a robotic welding additive manufacturing process. One or both of a welding output current and a wire feed speed are sampled during a robotic welding additive manufacturing process when creating a current weld layer. A plurality of instantaneous contact tip-to-work distances (CTWD's) are determined based on at least one or both of the welding output current and the wire feed speed. An average CTWD is determined based on the plurality of instantaneous CTWD's. A correction factor is generated, based on at least the average CTWD, which is used to compensate for any error in height of the current weld layer.