Additive Manufacturing Height Error Correction via CTWD Feedback
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Solution Overview
Problem
In additive manufacturing, the actual height of deposited layers often deviates from the expected height due to factors like surface conditions and parameter accuracy, leading to inconsistencies in the final workpiece part.
Innovation Solution
A system that samples output current, wire feed speed, and other parameters in real-time to determine instantaneous and average contact tip-to-work distances, generating a correction factor to adjust travel speed, duration, or wire feed speed to compensate for height errors in the current layer and improve the accuracy of subsequent layers.
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 implements real-time feedback by sampling output current and wire feed speed during additive manufacturing, determining instantaneous contact tip-to-work distances, calculating average CTWD, and generating correction factors that are applied to subsequent layers. This closed-loop feedback mechanism continuously monitors and adjusts deposition parameters to maintain layer height accuracy within tolerances.
Solution Approach 2:
The patent replaces complex mechanical measurement systems with electrical parameter-based calculations. Instead of using physical sensors to directly measure layer height, the system uses electrical measurements (output current, wire feed speed) to determine contact tip-to-work distance and calculate correction factors, simplifying the hardware while maintaining precision.
2Manufacturing precision
If correction factors are generated and applied, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary calculations during the deposition process itself. While creating the current layer, the system samples parameters, determines instantaneous CTWD values, calculates the average, and generates correction factors that are immediately applied to the next layer, eliminating the need for separate post-processing measurement and adjustment steps.
Solution Approach 2:
The correction process operates continuously throughout the additive manufacturing operation. Parameter sampling, CTWD determination, average calculation, and correction factor generation all occur in real-time during deposition without interrupting the manufacturing flow, ensuring continuous productive action while maintaining precision.
Data Source
AI summary
A system and method to correct for height error during a robotic additive manufacturing process. One or both of an output current, output voltage, output power, output circuit impedance and a wire feed speed are sampled during an additive manufacturing process when creating a current layer. A plurality of instantaneous contact tip-to-work distances (CTWD's) are determined based on at least one or both of the output current, output voltage, output power, output circuit impedance 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 layer.