Decoupled Weave Axis End Effector for Precise WAAM Welding

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Solution Overview

Problem

Existing wire arc additive manufacturing (WAAM) processes face inefficiencies and inaccuracies due to the reliance on industrial robots that are not optimized for fine weaving motions, leading to inconsistent weld quality, mechanical stress, and positional inaccuracies, particularly when building large-scale industrial components.

Innovation Solution

Implementing a weave axis system that decouples weaving movements from the robot, allowing for precise, high-frequency, and lightweight control of the welding torch through a modular interface and motor control, independent of the robotic actuator, enabling consistent and efficient weaving patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If industrial robots are used for WAAM processes, then automation and productivity are improved, but manufacturing precision and reliability deteriorate due to mechanical stress, wear, and inability to perform fine weaving motions

Engineering Contradiction:
ImproveautomationVSAvoidweaving accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system divides the motion control into two independent segments: the robotic actuator handles gross positioning movements, while the weave axis system handles fine weaving motions. This segmentation allows each subsystem to optimize its function without interfering with the other, resolving the contradiction between automation and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The weave axis system acts as an intermediary device mounted on the robotic actuator. It mediates between the robot's coarse movements and the welding torch's required fine positioning, enabling precise weaving patterns while maintaining the benefits of robotic automation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If robotic actuators perform weaving motions, then automation is maintained, but manufacturing precision worsens due to positional inaccuracies and mechanical limitations

Engineering Contradiction:
Improverobotic controlVSAvoidposition accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The control system is segmented into two independent control loops: robotic actuator control for positioning and weave axis control for pattern execution. This allows high-precision weaving patterns to be executed independently of the robot's positioning accuracy, maintaining both automation and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system replaces the mechanical weaving capability (which would require complex robotic motion control) with a dedicated weave axis system that uses simpler, more precise mechanical motion for pattern execution, thereby improving position accuracy while maintaining automation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If high-frequency weaving motions are implemented, then manufacturing precision improves, but device complexity increases due to additional motors and control systems

Engineering Contradiction:
Improveweld qualityVSAvoidsystem structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The weaving function is extracted from the robotic actuator and implemented as a separate, dedicated weave axis system. This extraction allows the weaving mechanism to be optimized for high-frequency motions without adding complexity to the entire robotic system, as the weave axis is a self-contained module with its own motor and control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The weave axis system is designed as a universal module that can be mounted on various robotic actuators and configured for different weaving patterns and frequencies. This multi-functionality allows high-precision welding across different applications without requiring custom complex systems for each case.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If decoupled weave axis system is used, then manufacturing precision and repeatability improve, but device complexity increases due to modular interface and additional components

Engineering Contradiction:
ImproverepeatabilityVSAvoidmodular structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system is segmented into modular components (robotic actuator, weave axis system, end effector) with standardized interfaces. This segmentation improves repeatability by allowing each module to be independently optimized and calibrated, while the modular interface simplifies assembly and maintenance, offsetting the apparent complexity increase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The modular design allows independent adjustment of parameters for each subsystem (robotic positioning parameters, weaving frequency, amplitude, pattern). This parameter independence enhances repeatability by allowing precise tuning of each function without affecting the other, while the standardized modular interface manages the complexity through consistency and reusability.

Inventive Principle:
Principle #35Parameter changes

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 weave axis system achieves improved accuracy, repeatability, and throughput in WAAM processes by reducing mechanical stress on robots, enhancing weld quality, and ensuring consistent material deposition across various cells and poses.

Implementation Method 1

a motor configured to control a movement of the end effector; wherein the movement of the end effector is decoupled from a movement of the robotic actuator

Methodology Applied
Scientific EffectMechanical motion control:

Implementation Method 2

Wire Arc Additive Manufacturing (WAAM) is a metal-part manufacturing technology that uses directed energy deposition and arc welding to create 3D parts by depositing layers of metal

Methodology Applied
Scientific EffectArc welding: Electric Arc

Implementation Method 3

Wire Arc Additive Manufacturing (WAAM) is a metal-part manufacturing technology that uses directed energy deposition and arc welding to create 3D parts by depositing layers of metal

Methodology Applied
Scientific EffectDirected energy deposition:

Data Source

PatentEP4647198A1End effector assembly, systems and methods for weaving in additive manufacturing
Publication Date: 2025.11.12 RELATIVITY SPACE INC
  • EP4647198A1 patent drawingFigure 1A~1B
  • EP4647198A1 patent drawingFigure 2A
  • EP4647198A1 patent drawingFigure 2B

AI summary

Systems and methods for implementing weaving in additive manufacturing are described. The weaving can be controlled by a localized system to achieve fine movement accuracy. The system can include a motor to move the print head in a multi axes motion. The system can improve print consistency and quality.