CMT Welding Bead Control Through Peak Current Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
CMT welding techniques struggle to maintain a constant welding bead shape during additive manufacturing due to changes in tip-base metal distance, which affect the average feeding speed of the welding wire, leading to instability in the welding process.
Innovation Solution
A control method that maintains a constant average feeding speed of the welding wire by associating peak current values with short-circuit times, adjusting the peak current for each cycle to ensure the short-circuit time falls within a target range, thereby stabilizing the welding bead shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tip-base metal distance is changed in CMT welding, then the welding process can adapt to different workpiece configurations, but the average feeding speed of the welding wire changes, causing welding bead shape instability
Solution Approach 1:
The patent implements a feedback control mechanism where the actual short-circuit time is measured and compared against the target short-circuit time. Based on this comparison, the peak current value is adjusted in real-time to compensate for changes in tip-base metal distance. This closed-loop feedback system ensures that welding bead shape remains consistent even when tip-base metal distance varies, directly resolving the technical contradiction between adaptability and manufacturing precision.
Solution Approach 2:
The patent changes the peak current value parameter dynamically based on the detected short-circuit time. By associating peak current values with specific short-circuit times and adjusting the peak current in real-time, the system compensates for distance variations without changing the average feeding speed. This parameter change approach allows the welding process to adapt to different tip-base metal distances while maintaining consistent welding bead shape.
2Reliability
If the peak current is increased to maintain arc stability, then the arc can be reliably sustained, but the short-circuit time increases, affecting the welding bead shape
Solution Approach 1:
The patent establishes an association between peak current values and short-circuit times, creating a controlled relationship between these two parameters. By selecting specific peak current values from this association based on the desired short-circuit time, the system can maintain arc stability while precisely controlling the short-circuit duration. This parameter association and dynamic adjustment resolve the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent makes the peak current value dynamic rather than fixed, allowing it to change based on the detected short-circuit time. This dynamic adjustment enables the system to optimize arc stability for each welding cycle while maintaining consistent short-circuit timing, thereby achieving both reliable arc performance and precise welding bead shape control.
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 method ensures a consistent welding bead shape in real-time, even with changes in tip-base metal distance, by using real-time feedback control to adjust the peak current based on characteristic information, enhancing process stability and shape accuracy in additive manufacturing.
Implementation Method 1
CMT (Cold Metal Transfer) welding is known as a method of welding by intermittently generating an arc through feeding a welding wire forward and backward and controlling energization between a contact tip and a molten pool
Implementation Method 2
the welding wire is pulled back after the short circuit, thereby promoting the separation of the droplets and controlling a welding current at the time of the arc reignition to a minimum limit
Data Source
AI summary
A control method for a welding bead shape at the time of manufacturing an additively manufactured object by repeatedly depositing welding beads formed by periodically repeating a forward feeding period and a backward feeding period of a welding wire as one cycle and providing an arc period and a short-circuit period during the one cycle. The method includes keeping an average feeding speed of the welding wire constant, and based on characteristic information in which a peak current value at which a welding current rises from a base current and a short-circuit time that is a length of the short-circuit period in the one cycle are associated with each other, detecting the short-circuit time and controlling the peak current value for each cycle of feeding of the welding wire so that the short-circuit time falls within a target range determined according to the characteristic information.