Weld Bead Laminate Molding With In-Process Trajectory Correction
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Solution Overview
Problem
Existing additive manufacturing methods face challenges in accurately controlling the width and height of weld beads due to variations in sensor measurements and the lack of absolute positioning references, leading to reduced accuracy and stability in forming additively-manufactured objects.
Innovation Solution
An additive manufacturing method that uses a non-contact shape sensor on a welding torch to measure the shape of existing weld beads, extract geometric information, calculate deviations, and update the deposition track plan and welding conditions to achieve precise bead formation, including adjustments to bead height and width, ensuring accurate positioning and shape approximation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If real-time measurement with laser sensor is used to shorten tact time, then productivity is improved, but measurement precision deteriorates due to large variation in detected values
Solution Approach 1:
The patent implements a feedback mechanism where the laser sensor measures the actual bead shape during deposition, and this measurement is used to adjust the deposition track plan for subsequent beads. The system calculates deviation between target and actual bead shapes, then modifies the next bead's target position and shape parameters accordingly, creating a closed-loop control system that improves measurement reliability while maintaining real-time operation.
Solution Approach 2:
The patent performs preliminary calculation of the deposition track plan before actual deposition begins. The system pre-calculates the target bead shapes and positions based on the desired final geometry, then uses real-time measurements to adjust this pre-planned trajectory. This allows the system to prepare compensation strategies in advance while responding to actual measurement variations during the process.
2Manufacturing precision
If feedback control is performed by measuring bead shape and adjusting next step parameters, then manufacturing precision is improved, but loss of time increases due to measurement and calculation requirements
Solution Approach 1:
The patent extracts only the essential geometric features from the full bead shape measurement data. Instead of processing the complete three-dimensional bead profile, the system identifies and uses key parameters such as bead height, width at specific positions, and overall shape characteristics. This extraction of critical information reduces calculation complexity and time while maintaining the ability to make accurate adjustments to subsequent bead deposition.
3Ease of operation
If non-contact shape sensor is mounted on robot tip shaft integrally with welding torch, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent merges the non-contact shape sensor with the welding torch assembly, mounting it on the robot tip shaft so that both the torch and sensor move together as a single unit. This integration ensures that the sensor maintains a consistent relative position to the bead formation area, eliminating the need for separate positioning systems and reducing operational complexity despite the initial integration challenge.
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 method enables the accurate determination of the target position for bead formation, resulting in high-accuracy manufacturing of additively-manufactured objects with improved stability and reduced measurement time, achieving accuracy of up to 0.1 mm.
Implementation Method 1
measuring a shape profile of an existing weld bead by a non-contact shape sensor provided on the robot tip shaft integrally with the welding torch
Implementation Method 2
depositing weld beads formed by melting and solidifying a filler metal
Implementation Method 3
melting and solidifying a filler metal while moving a welding torch
Data Source
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AI summary
According to the present invention, the shape profile of an existing weld bead is measured by means of a non-contact type shape sensor provided integrally with a welding torch on a robot tip end shaft, midway through molding of a laminate molded object on the basis of a lamination trajectory plan. First geometric information relating to the bead shape is extracted from the shape profile and the target position of the welding torch, second geometric information corresponding to the first geometric information is extracted from the lamination trajectory plan, and an offset amount is calculated from the first geometric information and the second geometric information. In accordance with the offset amount, the lamination traj ectory plan is updated by updating at least one of the bead height and the bead width of the weld bead determined by the lamination trajectory plan, and the welding conditions are updated in accordance with the result of updating the lamination trajectory plan.