Wire Arc AM Bead Control Using Dual Measurement Feedback
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Solution Overview
Problem
Existing methods for manufacturing additively-manufactured objects face challenges in controlling the width and height of weld beads with precision, particularly when laser sensors are unable to measure the bead shape effectively, leading to difficulties in feedback control.
Innovation Solution
A system and method that utilize a combination of a first measurement unit, such as a laser sensor, and a second measurement unit to measure current, voltage, and filler metal supply rate, allowing for selection and correction of control parameters like robot arm movement, current, voltage, and filler metal supply rate to achieve precise bead shape control, even when the laser sensor is obstructed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser sensor is used to measure bead height for feedback control, then manufacturing precision is improved, but the system becomes unreliable when the bead cannot be measured by the laser sensor
Solution Approach 1:
The system changes the measurement parameter from direct optical measurement (laser sensor) to indirect electrical parameter measurement (current, voltage, wire feed speed) when the laser sensor cannot obtain valid bead height data. This parameter substitution allows the system to maintain measurement capability under different conditions, resolving the reliability issue while preserving manufacturing precision through alternative measurement approaches.
2Reliability
If multiple measurement methods are used to ensure measurement reliability, then system complexity increases
Solution Approach 1:
The control device is designed to perform multiple functions: it can process laser sensor measurement data when available, and alternatively process electrical parameter data (current, voltage, wire feed speed) when the laser sensor fails. This multi-functionality allows a single integrated system to handle both measurement approaches, increasing reliability without requiring completely separate measurement systems.
Solution Approach 2:
The system implements feedback control by continuously monitoring both laser sensor measurements and electrical parameters, comparing them against target values, and automatically adjusting welding parameters to maintain bead height precision. The feedback mechanism selects appropriate measurement data sources based on availability, ensuring reliable control while managing system complexity through intelligent data selection and processing.
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
Enables the selection of appropriate measurement results to ensure high precision in manufacturing additively-manufactured objects by compensating for obstructions and surface irregularities, allowing for accurate control of weld bead dimensions.
Implementation Method 1
a first measurement unit that is mounted on the torch and that directly measures, in a non-contact manner, a base shape of a base portion on which the weld beads are deposited
Implementation Method 2
an additively-manufactured object obtained by depositing a plurality of weld beads formed by melting and solidifying a filler metal using an arc on a base material
Data Source
AI summary
A system for manufacturing an additively-manufactured object obtained by depositing weld beads based on a depositing plan, the system includes: a torch that is provided on a robot arm; a first measurement unit that is mounted on the torch and that directly measures, in a non-contact manner, a base shape of a base portion on which the weld beads are deposited; a second measurement unit that measures at least one of a current, a voltage, and a filler metal supply rate when the weld beads are deposited, and estimates the base shape from history change thereof; and a control unit that selects at least either of a measurement result by the first measurement unit or by the second measurement unit and corrects control of at least one of the robot arm, the current, the voltage, and the filler metal supply rate.