Amorphous Alloy Ribbon Laser Scribing for Low Iron Loss

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Solution Overview

Problem

Existing soft-magnetic amorphous alloy ribbons suffer from high anomalous eddy current loss and increased apparent power due to non-uniform magnetization changes, leading to higher iron loss and reduced lamination factors, especially in thinner ribbons, when using conventional laser-scribing methods that result in molten alloy splashes and deep recesses.

Innovation Solution

The method involves forming transverse lines of recesses on the amorphous alloy ribbon with laser beams, controlling the irradiation conditions to create doughnut-shaped projections with smooth surfaces and a specific depth-to-thickness ratio of 0.025-0.18, suppressing the formation of molten alloy splashes and maintaining a high lamination factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional laser-scribing methods are used to divide magnetic domains, then iron loss is reduced, but apparent power increases and lamination factor decreases due to molten alloy splashes and deep recesses

Engineering Contradiction:
Improveiron lossVSAvoidapparent power
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The invention changes the laser irradiation parameters (energy density, pulse duration, scanning speed) to control the depth and morphology of recesses. By optimizing these parameters, the recess depth is limited to 0.5-2.0 μm, preventing deep melting that causes splashes, while still achieving magnetic domain division to reduce iron loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies partial action by using shallow laser scribing that only creates surface recesses without deep melting. This partial melting approach is sufficient to divide magnetic domains and reduce iron loss, while avoiding the excessive melting that generates splashes and increases apparent power.

Inventive Principle:
Principle #16Partial or excessive action

2Loss of energy

If deep recesses are formed by high energy density laser beams, then magnetic domains are divided and iron loss decreases, but molten alloy splashes increase causing apparent power increase and lamination factor decrease

Engineering Contradiction:
Improveiron lossVSAvoidlamination factor
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The invention optimizes laser processing parameters including energy density (0.1-1.0 J/cm²), pulse width (10-100 μs), and scanning speed to control recess depth within 0.5-2.0 μm. These parameter changes ensure precise surface modification without deep melting, maintaining high lamination factor while achieving domain division.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces mechanical domain division methods with controlled laser surface modification. The laser creates shallow recesses that physically divide magnetic domains without the mechanical contact and damage associated with traditional methods, preserving surface quality and lamination factor.

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

3Loss of energy

If thin amorphous alloy ribbons are used, then iron loss decreases, but they are more influenced by laser-scribed surface conditions causing increased apparent power

Engineering Contradiction:
Improveiron lossVSAvoidapparent power
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The invention adjusts laser parameters specifically for thin ribbons, using lower energy density and shorter pulse durations to create even shallower recesses (0.5-2.0 μm). This controlled approach ensures that thin ribbons receive sufficient domain division treatment without excessive surface damage that would increase apparent power.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by creating localized shallow recesses only at specific intervals along the ribbon surface. This localized treatment divides magnetic domains where needed while leaving the majority of the thin ribbon surface undisturbed, minimizing the overall impact on apparent power.

Inventive Principle:
Principle #3Local quality

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 approach effectively reduces iron loss and apparent power while maintaining a high lamination factor, resulting in efficient magnetic cores suitable for transformers and reactors with reduced sound noise.

Implementation Method 1

a laser-scribing method of irradiating a surface of an amorphous alloy ribbon with laser beams to cause local melting and rapid solidification

Methodology Applied
Scientific EffectLaser heating and rapid solidification: Laser

Implementation Method 2

irradiating a surface of an amorphous alloy ribbon with laser beams to cause local melting

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2463868B1Soft magnetic amorphous alloy ribbon, method for producing same, and magnetic core using same
Publication Date: 2015.07.15 PROTERIAL LTD
  • EP2463868B1 patent drawingFigure 1
  • EP2463868B1 patent drawingFigure 2(a)~2(b)
  • EP2463868B1 patent drawingFigure 3~4(b)

AI summary

A soft-magnetic, amorphous alloy ribbon produced by a rapid quenching method, having transverse lines of recesses formed on its surface by laser beams with predetermined longitudinal intervals, with a doughnut-shaped projection formed around each recess; doughnut-shaped projections having smooth surfaces substantially free from splashes of the alloy melted by the irradiation of laser beams, and a height t2 of 2 µm or less; and a ratio t1/T of the depth t1 of the recesses to the thickness T of the ribbon being in a range of 0.025-0.8, thereby having low iron loss and low apparent power.