Metal Layering Trajectory Control for Flat Bead Overlap

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Solution Overview

Problem

Existing methods for adding molten metal layer by layer to form objects, such as in 3D metal printing, fail to ensure a flat surface, leading to inconsistent weld deposition and potential gaps, which affect the quality and stability of the final product.

Innovation Solution

A trajectory determining device and control method that generates control information for the adding device to adjust the trajectory and adding conditions, such as molten metal quantity and travel speed, to achieve a specific overlap ratio between adjacent beads, ensuring a flat surface by calculating the flatness index and overlap ratio, thereby stabilizing the arc and improving object quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the same quantity of molten metal is supplied at the same travel speed, then the beads have basically the same height, but the surface formed by adjacent beads is not flat

Engineering Contradiction:
Improvebead height consistencyVSAvoidsurface flatness
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The patent applies dynamics by making the travel speed variable rather than constant. The control information dynamically adjusts the travel speed of the adding device based on the trajectory to achieve a specific overlap ratio between adjacent beads, ensuring surface flatness while maintaining bead height consistency through adaptive parameter changes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of travel speed to control the overlap ratio between adjacent beads. By modifying the travel speed parameter along different trajectory segments, the system achieves the desired surface flatness while maintaining consistent bead heights, resolving the contradiction between height consistency and surface flatness.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the surface is not flat, then the lack of weld deposition quantity occurs, but the arc stability becomes difficult to maintain

Engineering Contradiction:
Improveweld deposition quantityVSAvoidarc stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-calculating and providing control information that ensures flat surfaces before subsequent layers are added. This prevents weld deposition quantity deficits and maintains arc stability by ensuring the surface is properly prepared in advance for the next layer of deposition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by calculating the flatness index of the surface formed by adjacent beads and using this information to generate appropriate control information. This feedback mechanism ensures that the surface flatness is maintained within acceptable ranges, preventing weld deposition issues and maintaining arc stability.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If the molten metal is cooled, then gaps or cavities are created, but the object quality is affected

Engineering Contradiction:
Improvelayer continuityVSAvoidobject quality
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by adjusting the travel speed dynamically to control the cooling rate and solidification process of molten metal. By optimizing the travel speed, the system prevents excessive cooling that would create gaps or cavities, thereby maintaining layer continuity and object quality simultaneously.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies beforehand cushioning by ensuring proper overlap ratio between adjacent beads through controlled travel speed. This prevents gaps or cavities from forming in the first place by maintaining adequate material coverage, thus preventing rather than correcting defects that would affect object quality.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution ensures a flat surface for molten metal layers, preventing weld deposition height inconsistencies and gaps, thereby stabilizing the arc and enhancing the quality of the formed objects by maintaining consistent layer addition.

Implementation Method 1

3D printers using metal materials are configured to melt metal powder or metal wire using a heat source, such as a laser or arc, to add molten metal layer by layer to form an object

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

a welding torch configured to deliver droplets of metal wire melted by arc discharge toward a substrate facing the welding torch

Methodology Applied
Scientific EffectArc discharge: Electric Arc

Data Source

PatentEP3417973B1Layering control device, layering control method, and program
Publication Date: 2024.06.12 KOBE STEEL LTD
  • EP3417973B1 patent drawingFigure 1
  • EP3417973B1 patent drawingFigure 2
  • EP3417973B1 patent drawingFigure 3

AI summary

In a trajectory determination device (40): a CAD data acquisition unit (41) acquires shape data representing the shape of a three-dimensional structure; a trajectory data generating unit (43) and layering conditions adjusting unit (44) generate, on the basis of the shape data acquired by the CAD data acquisition unit (41), control information which is information for controlling a layering device for layering molten metal for forming the structure and which indicates the trajectory for the layering device and/or layering conditions when the layering device layers molten metal such that the upper surface of one layer of a plurality of layers of molten metal layered is flat; and a control program output unit (45) outputs the control information generated by the trajectory data generating unit (43) and the layering conditions adjusting unit (44).