3D Metal Print Head With Localized Inert Gas Nozzle

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Solution Overview

Problem

3D metal printing faces challenges with high inert gas consumption and oxide formation due to non-inert atmospheres, limiting the build rate and quality of metal workpieces.

Innovation Solution

A print head design that includes a housing with a reservoir and piston system for delivering metal, where an inert atmosphere is generated directly at the nozzle using a protective gas, reducing gas consumption and preventing oxidation by delivering inert gas only where needed during the printing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a closed chamber is sealed and filled with inert gas to prevent oxide formation, then print quality is maintained, but inert gas consumption increases

Engineering Contradiction:

Improveprint qualityVSAvoidinert gas consumption

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating an inert atmosphere only in the immediate vicinity of the discharge opening where metal droplets are formed and deposited, rather than filling the entire chamber with inert gas. The protective gas delivery device directs inert gas locally to the nozzle area, maintaining oxidation prevention at the critical deposition zone while reducing overall gas consumption in the chamber.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the chamber into zones with different atmospheric requirements. The discharge opening area receives protective inert gas to prevent oxidation, while the rest of the chamber can operate with reduced or no inert gas. This segmentation allows quality maintenance at the critical printing location without the cost of filling the entire volume with expensive inert gas.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the chamber is filled with inert gas at elevated pressure to maintain inert atmosphere, then oxide formation is prevented, but gas consumption and system complexity increase

Engineering Contradiction:

Improveoxide formation preventionVSAvoidinert gas consumption

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent uses inert atmosphere principle by delivering protective gas directly to the discharge opening to create a localized inert environment around the molten metal and deposited droplets. This prevents oxidation at the critical interface without requiring the entire chamber to be maintained at elevated inert gas pressure, thereby reducing overall gas consumption while still preventing oxide formation.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Productivity

If pneumatic drop-on-demand technique is used with pressure pulses, then metal droplets are formed, but build rate is limited due to gas compressibility

Engineering Contradiction:

Improvebuild rateVSAvoidactivation frequency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the pneumatic pressure pulse system with a mechanical piston-driven delivery system. The piston directly pushes molten metal through the discharge opening, eliminating the need for compressible gas intermediaries. This mechanical substitution enables higher activation frequencies and improved build rates because the incompressible piston can deliver droplets more rapidly and reliably than pneumatic systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 design reduces inert gas usage, maintains print quality, and allows for efficient metal delivery, enhancing the reproducibility and accuracy of metal droplet deposition in 3D metal printing.

Implementation Method 1

The metal raw material is melted by an induction heater in a reservoir

Methodology Applied

Scientific EffectElectromagnetic induction heating: Electromagnetic Induction

Implementation Method 2

the protective gas advantageously has the properties of an inert gas, or is an inert gas

Methodology Applied

Scientific EffectInert atmosphere:

Data Source

PatentUS12257630B2Print head for 3D printing of metals, device for additively manufacturing three-dimensional workpieces, comprising a print head and method for operating a device

Publication Date: 2025.03.25 ROBERT BOSCH GMBH

AI summary

The invention relates to a print head (1) for additively manufacturing three-dimensional workpieces, comprising a housing (3), a device (28) for feeding a metal (14), a piston (5), a reservoir (7) with an outlet opening (10) and an actuator device (12) for displacing the piston (5), wherein the reservoir (7, 27) has a melt region (20) and a displacement body chamber (21) for a liquid phase (8) of the metal (14), wherein the melt region (20) adjoins the inert atmosphere (22) and is connected to the displacement body chamber (21) such that, as a result of the displacement of the piston (5), the liquid phase (8) of the metal (14) can be stimulated to pass through the outlet opening (10), said outlet opening (10) being mounted on an insert (11) of the print head (1). The invention is characterised in that the print head (1) comprises a device (50) for feeding a protective gas (60) to the outlet opening (10) of the print head (1). The invention also relates to a device (100) for additively manufacturing three-dimensional workpieces and to a method for operating a print head (1).