Electron Beam Weld Tapering With Time-Multiplexed Dispersion Sweeps

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Solution Overview

Problem

Additive manufacturing processes, particularly in electron beam melting (EBM), face challenges with lack of fusion and uneven keyholes at the trailing edge of welds, leading to weaknesses and inefficiencies in the manufacturing process.

Innovation Solution

Implementing time multiplexing control of the electron beam to gradually taper the beam current and speed, avoiding keyhole formation by alternating welding and dispersion sweeps, ensuring a smooth transition at the weld edge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous welding is performed at high beam current and speed, then productivity is improved, but lack of fusion and keyhole formation occur at the trailing edge

Engineering Contradiction:

Improvewelding speedVSAvoidweld quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies periodic action by implementing time multiplexing that alternates between welding mode (high beam current, slower speed) and dispersion sweep mode (low beam current, faster speed). This periodic switching occurs at the trailing edge of each weld line, creating cycles of energy deposition followed by energy dispersion. The dispersion sweeps periodically remove excess material and close keyholes, preventing lack of fusion while maintaining overall high productivity through the efficiency of the welding phases.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent segments the continuous welding process into distinct temporal and spatial phases: the welding phase where material is deposited and fused, and the dispersion sweep phase where the trailing edge is treated to close keyholes and ensure fusion. This segmentation allows each phase to be optimized independently - welding for productivity and dispersion sweeps for weld quality - resolving the contradiction between speed and reliability.

Inventive Principle:

Principle #1Segmentation

2Productivity

If beam current is increased to improve welding efficiency, then productivity is improved, but keyhole formation and lack of fusion worsen

Engineering Contradiction:

Improvewelding efficiencyVSAvoidkeyhole formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful keyhole formation caused by high beam current into a beneficial process feature. The high beam current intentionally creates keyholes during the welding phase, which then serve as targets for the subsequent dispersion sweep phase. The dispersion sweeps use low beam current to gently close these keyholes and ensure complete fusion, transforming the potential defect into a controlled process step that guarantees weld quality while maintaining high overall efficiency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If welding speed is increased to improve productivity, then manufacturing efficiency is improved, but weld quality and fusion completeness deteriorate

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidweld quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements periodic action with alternating speed regimes: slower welding speed during material deposition to ensure proper fusion, followed by faster dispersion sweep speed at the trailing edge to close keyholes and clean up the weld. This periodic variation in speed maintains manufacturing efficiency by spending most time at higher speeds while ensuring quality through controlled slower phases.

Inventive Principle:

Principle #19Periodic action

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 enhances the quality of welds by reducing lack of fusion and keyhole effects, improving the reliability and efficiency of the additive manufacturing process without compromising productivity.

Implementation Method 1

control an energy beam... to form a weld from a powder

Methodology Applied

Scientific EffectElectron beam heating: Electron Beam

Implementation Method 2

heat the powder to a melting temperature

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

perform a dispersion sweep... avoiding keyhole formation

Methodology Applied

Scientific EffectThermal evaporation: Evaporation

Data Source

PatentUS12350741B2Systems and methods for weld tapering at a trailing edge using time multiplexing

Publication Date: 2025.07.08 ARCAM AB

AI summary

Systems, apparatus, and methods for weld tapering at a trailing edge using time multiplexing are disclosed. Systems, apparatus, and methods for control of an electron beam for welding using time multiplexing are disclosed. An example apparatus includes memory and at least one processor to execute instructions to at least: in a first portion of a line of an object being formed, control an energy beam at a first position at a first time to form a weld from a powder; and in a second portion of a line of the object being formed, control the energy beam to perform a dispersion sweep at a second position at a second time.