Hybrid WAAM Layer Control for Defect-Reduced Metal Additive Manufacturing

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Solution Overview

Problem

Existing additive metal production methods using wire-arc additive manufacturing (WAAM) face issues with internal defects such as pores, incomplete fusions, cracks, and shrinkage porosity due to high melting and solidification speeds, leading to unreliable and costly manufacturing processes.

Innovation Solution

A method utilizing a hybrid arc deposition and laser beam process with a controlled deposition pitch and offset adjustment based on real-time height measurements, ensuring precise layer formation and correction to maintain consistency with the CAD model, using a modeling program for fine-pitch stratification and feedback-controlled deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high melting and solidification speeds are used in WAAM process, then productivity is improved, but internal defects such as pores, incomplete fusions, cracks, and shrinkage porosity increase

Engineering Contradiction:
Improvemelting and solidification speedVSAvoidinternal defects
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback control system that uses height sensors to detect the actual height of deposited layers in real-time. The system compares measured heights with theoretical heights and dynamically adjusts deposition parameters (such as deposition pitch and offset) to compensate for variations, ensuring consistent layer quality and minimizing internal defects while maintaining high productivity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes deposition parameters based on real-time measurements. The deposition pitch and offset are adjusted according to the detected layer height, allowing the system to optimize melting and solidification conditions for each layer to prevent defects while maintaining high deposition speeds

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If laser beams are used to melt wire and transfer onto manufactured article, then manufacturing precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvequality of manufactured articleVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses an arc deposition torch as an intermediary between the filler wire and the manufactured article. The torch delivers filler metal in a controlled manner without requiring complex laser systems, achieving good manufacturing precision while keeping the device structure relatively simple and cost-effective

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If arc deposition torch with filler wire is used, then productivity and cost-effectiveness are improved, but manufacturing precision deteriorates due to large melting pools and residual deformations

Engineering Contradiction:
Improveoperating speedVSAvoidresidual deformations
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs real-time feedback control using height sensors to monitor layer deposition. The system adjusts deposition parameters based on measured heights, compensating for thermal deformations and ensuring manufacturing precision is maintained while preserving the productivity advantages of arc deposition

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the deposition system dynamic by continuously adjusting deposition pitch and offset based on real-time height measurements. This dynamic adaptation allows the system to compensate for thermal effects and maintain precision throughout the manufacturing process while operating at high speeds

Inventive Principle:
Principle #15Dynamics

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

Ensures high reliability, high operating speed, and low cost production of metal articles with minimized defects, achieving precise and repeatable manufacturing results without the need for subsequent machining.

Implementation Method 1

an operating head (30) supporting an arc deposition torch (31)

Methodology Applied
Scientific EffectArc deposition: Electric Arc

Implementation Method 2

laser beam generation means... The use of laser beams for generating fusion energy

Methodology Applied
Scientific EffectLaser beam heating: Laser

Data Source

PatentEP4578582A1Method of additive manufacturing metal articles by means of superimposed layers and respective equipment
Publication Date: 2025.07.02 L M N SRL
  • EP4578582A1 patent drawingFigure 1
  • EP4578582A1 patent drawingFigure 2
  • EP4578582A1 patent drawingFigure 3~3b

AI summary

Method for the additive metal production of manufactured articles (22) by forming superimposed layers (24), using an equipment (21) comprising an operating head (30) equipped with an arc deposition torch (31) with a metal filler wire (34) of filler, laser beam generation means (33), movement means (32-1; 32-2; and 32-3) for moving the operating head, an electronic control and command unit (39) and a modeling program (27) of the manufactured article. The operating head (30) comprises optical means (47) connected to the means for generating laser beams for a hybrid formation of the layers (LAMWD), a temperature sensor (38) and a height sensor (51) for the layers being formed. The modeling program (27) provides for an elementary stratification with a fine pitch which represents the set of the possible paths to be used for the growth of the manufactured article, the feeding device for the filler wire is controlled so as to grow the manufactured article with a deposition layer according to the model parameters. The growth steps are determined by depositing a new layer in accordance with a correct elementary layer, updated deposition pitch and updated deposition offset for a controlled growth and a precise progression of the manufactured article.