Weld Bead Profile Feedback for Precise Laminate Molding
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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 the welding torch to measure the shape profile of existing weld beads, extract geometric information, calculate deviations, and update the deposition track plan to adjust bead height and width, and change welding conditions to achieve precise target positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If real-time measurement of weld bead shape is performed using a laser sensor to enable feedback control, then manufacturing precision can be improved, but measurement stability deteriorates due to large variations in detected values caused by sensor light receiving sensitivity and linearity issues
Solution Approach 1:
The patent introduces an intermediary processing step between measurement and control: instead of directly using raw sensor measurements, the system performs coordinate transformation to convert sensor coordinates to torch tip coordinates, and applies smoothing processing to eliminate measurement variations. This intermediary processing stabilizes the measurement data while maintaining the ability to achieve precise control.
Solution Approach 2:
The patent replaces the traditional mechanical positioning reference system (grooves) with an optical measurement and coordinate transformation system. By using laser sensor measurements combined with coordinate transformation based on torch attitude angles, the system achieves accurate positioning without relying on physical mechanical references, thereby improving both precision and reliability.
2Manufacturing precision
If groove welding is used to provide positioning references for accurate bead formation, then manufacturing precision is improved, but adaptability deteriorates because there is no absolute positioning reference available in padding operations for additive manufacturing
Solution Approach 1:
The patent inverts the traditional approach: instead of using fixed mechanical references (grooves) to define position, the system uses the torch tip position and attitude as the reference frame, and measures bead shape relative to this moving reference. This inversion allows the same system to work for both groove welding and padding operations, significantly improving adaptability while maintaining precision.
Solution Approach 2:
The patent creates a universal positioning and control system that can handle both groove welding and padding operations. By using coordinate transformation based on torch tip position and attitude angles, the system provides a common reference framework that works for different welding modes, eliminating the need for mode-specific positioning methods.
3Manufacturing precision
If the target position for bead formation is adjusted based on measured bead shape, then manufacturing precision can be improved, but productivity deteriorates due to the time required for stable measurement
Solution Approach 1:
The patent performs preliminary coordinate transformation and smoothing processing on measurement data immediately after acquisition, before using the data for control decisions. This preliminary processing rapidly eliminates measurement variations and provides stable results quickly, reducing the time needed to achieve reliable measurements without sacrificing precision.
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 accurate determination of the target position for bead formation, resulting in high-accuracy manufacturing of additively-manufactured objects by reducing measurement variations and stabilizing the welding process.
Implementation Method 1
measuring a shape profile of an existing weld bead by a non-contact shape sensor
Implementation Method 2
weld beads formed by melting and solidifying a filler metal while moving a welding torch
Data Source
AI summary
The shape profile of an existing weld bead is measured by 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 deposition track plan, and an offset amount is calculated from the first geometric information and the second geometric information. In accordance with the offset amount, the deposition track plan is updated by updating at least one of the bead height and the bead width of the weld bead determined by the deposition track plan, and the welding conditions are updated in accordance with the update result of the deposition track plan.