Coaxial Laser-Wire Optics Using Reflective Mirrors for High Deposition

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Solution Overview

Problem

Current laser beam wire deposition systems in additive manufacturing are limited by the use of transmissive optical elements, which are fragile and prone to contamination, restricting the consistent delivery of high laser power and thus limiting material deposition rates.

Innovation Solution

The system employs a fully reflective and water-cooled optical design with conical or toroidal mirrors, eliminating the need for transmissive optics and allowing for the delivery of up to 20 kW of laser power, enabling higher material deposition rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transmissive optical elements are used for laser beam delivery, then the system can deliver laser power to melt the wire, but the transmissive elements are fragile and prone to contamination, limiting the consistent delivery of high laser power

Engineering Contradiction:
Improveconsistency of laser power deliveryVSAvoidcontamination and fragility of transmissive optics
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes transmissive optical elements from the laser beam path entirely, extracting the problematic component that causes contamination and fragility issues. The system uses only reflective optics (mirrors) to deliver the laser beam, eliminating the harmful effects associated with transmissive elements while maintaining the ability to deliver high laser power consistently.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the optical parameter from transmissive to reflective by using mirrors instead of lenses or windows. This parameter change transforms the interaction between laser light and optical elements, allowing for higher power delivery without the contamination and fragility limitations of transmissive materials.

Inventive Principle:
Principle #35Parameter changes

2Power

If transmissive optical elements are used, then laser power can be delivered to the wire, but the elements limit the amount of power that can be consistently delivered

Engineering Contradiction:
Improvelaser power delivery capabilityVSAvoidconsistency of power delivery
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

By removing transmissive optical elements from the system, the patent eliminates the power delivery limitations imposed by these elements. The reflective optics can handle higher laser powers without the thermal distortion and contamination issues that plague transmissive elements, enabling both higher and more consistent power delivery.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If protective transmissive windows are used in coaxial wire feed heads, then the optics are protected, but they are prone to contamination and thermal distortion, limiting process robustness

Engineering Contradiction:
Improveprocess robustnessVSAvoidcontamination and thermal distortion of windows
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the protective transmissive windows from the coaxial wire feed head design. By using only reflective optics, the system eliminates the windows that are susceptible to contamination and thermal distortion, thereby improving process robustness without sacrificing optical protection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the optical parameter from transmissive to reflective, transforming how the optical system interacts with the environment. This parameter change eliminates the vulnerability to contamination and thermal distortion while maintaining the necessary optical functionality for high-power laser delivery.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If conventional optical systems are used, then laser power can be delivered to the wire, but the material deposition rate is limited to 250 cm³/hr

Engineering Contradiction:
Improvematerial deposition rateVSAvoidlaser power delivery capability
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

By removing the limiting transmissive optical elements, the patent enables the system to deliver higher laser powers that are necessary for achieving dramatically increased material deposition rates. The reflective optics remove the power delivery ceiling that constrained conventional systems to 250 cm³/hr.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the optical configuration from transmissive to reflective, a parameter change that enables higher power transmission without the limitations of transmissive materials. This allows the system to achieve deposition rates up to 766 cm³/hr by delivering the necessary laser power efficiently.

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

This solution achieves significantly higher metal deposition rates, potentially reaching 766 cm³/hr or 13.5 lb/hr of stainless steel, compared to the 250 cm³/hr or 4.41 lb/hr limit of conventional systems, while maintaining process robustness and stability.

Implementation Method 1

The system employs a fully reflective and water-cooled optical design with conical or toroidal mirrors

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

water-cooled optical design

Methodology Applied
Scientific EffectConvection cooling: Convection

Implementation Method 3

supportive plate is adapted to provide cooling water to the interior of the optical housing

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the pressurized gas provides shielding at a work surface involving the wire

Methodology Applied
Scientific EffectGas shielding:

Implementation Method 5

laser directs a laser beam into and through the optical housing

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 6

laser power delivery capability for melting the wire

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4021668B1Coaxial laser-wire optical system for use in additive manufacturing
Publication Date: 2025.06.11 EDISON WELDING INSTITUTE INC
  • EP4021668B1 patent drawingFigure 1
  • EP4021668B1 patent drawingFigure 2
  • EP4021668B1 patent drawingFigure 3A

AI summary

A feed head apparatus for use in laser wire additive manufacturing, comprising an optical housing adapted to receive a laser beam therein and a wire therein, wherein the wire is adapted for use in additive manufacturing; a first reflective optic for receiving and reflecting the laser beam; and a second reflective optic for receiving laser light reflected by the first reflective optic, wherein the second reflective optic directs the laser light received from the first reflective optic onto the wire in a cylindrical configuration such that the wire and the cylinder of laser light are coaxial with regard to one another within a portion of the optical housing.