Additive Manufacturing Nozzle with Internal Spindle for Viscosity Control
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Solution Overview
Problem
Existing additive manufacturing technologies face challenges in controlling the viscosity of semi-solid and liquid metal materials during extrusion, particularly with shear-thinning and thixotropic fluids, and in maintaining an inert environment to prevent oxidation, especially at elevated temperatures.
Innovation Solution
A nozzle apparatus with an internal spindle that imparts motion to the extruding material, providing controlled agitation and fluid strain to manage viscosity, and a sealing mechanism that allows mechanical feedthrough access without using temperature-sensitive materials, mimicking a peristaltic pump motion to distribute shear strain throughout the fluid volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical agitation means are used to control viscosity of semi-solid metals during extrusion, then the material flow and extrusion rate are improved, but the sealing complexity increases due to the need for mechanical feedthrough access to the inert enclosure
Solution Approach 1:
The patent replaces mechanical agitation with acoustic waves (ultrasonic vibration) to control material viscosity and flow during extrusion. This eliminates the need for mechanical feedthroughs and complex sealing systems, as the acoustic field can be introduced through non-contact or minimal-contact means while maintaining the inert enclosure integrity.
Solution Approach 2:
The system uses acoustic pressure waves (a form of wave mechanics) to agitate the semi-solid material, creating cavitation and reducing viscosity without requiring physical mechanical components inside the sealed enclosure. This allows productivity improvement without increasing sealing complexity.
2Ease of operation
If the extrusion temperature is increased to improve material flow, then the viscosity decreases and extrusion becomes easier, but oxidation and contamination of the material increases
Solution Approach 1:
The patent maintains an inert atmosphere (e.g., argon or nitrogen gas) within the extrusion enclosure to prevent oxidation of semi-solid metals. By keeping the material temperature below the melting point and using acoustic agitation instead of thermal heating, the system achieves easy material flow without compromising the inert environment, thus preventing oxidation and contamination.
Solution Approach 2:
Instead of using high temperatures to reduce viscosity, the patent employs ultrasonic acoustic waves to agitate the material and reduce its viscosity dynamically during extrusion. This allows the material to flow easily at lower temperatures, maintaining the inert atmosphere's effectiveness and preventing oxidation.
3Manufacturing precision
If acoustic waves are used to agitate the material, then viscosity control and extrusion precision are improved, but the system complexity increases due to acoustic field generation requirements
Solution Approach 1:
The patent uses ultrasonic transducers to generate acoustic waves that propagate through the semi-solid material, providing precise control over viscosity and flow characteristics. The acoustic field can be localized and controlled through electronic means, allowing for precise extrusion control without requiring complex mechanical systems. The transducers are integrated into the extrusion tooling, minimizing additional system complexity.
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 effectively controls the viscosity and extrusion rate of semi-solid and liquid metals, preventing oxidation and allowing for the additive manufacturing of metals and alloys while maintaining a stable, inert environment, even at elevated temperatures.
Implementation Method 1
The material viscosity and time rate of change of viscosity having a correlation to extrusion parameters. In some embodiments, the extruded material must be maintained in an inert environment enclosure
Implementation Method 2
viscosity may be affected by fluid strain, exhibiting shear-thinning or shear-thickening behavior
Implementation Method 3
an acoustic wave generator coupled to the interior surface of the inert enclosure and configured to create acoustic waves that propagate through the material
Implementation Method 4
the acoustic waves cause an acoustic streaming effect that agitates and mixes the material
Implementation Method 5
the acoustic waves cause an acoustic streaming effect that agitates and mixes the material
Implementation Method 6
the extruded material must be maintained in an inert environment enclosure, for example to prevent oxidation of an extruding liquid metal or alloy
Data Source
AI summary
A nozzle apparatus used for extruding a material includes an internal spindle that imparts motion into the extruding material, the internal spindle having a base; a multiple degree-of-freedom pivot at the base of the internal spindle, and a drive mechanism that controls the motion of the internal spindle. In one embodiment the material is a semi-solid metal or alloy. In another embodiment the material is a shear thinning mixture or material. In yet embodiment the material is a thixotropic mixture or material. The nozzle apparatus can be used for making a three-dimensional object with the steps of providing a material; providing a nozzle that extrudes the material, the nozzle having an internal spindle that imparts motion into the material; positioning the nozzle above a support structure; and moving the nozzle in a three-dimensional pattern while extruding the material through the nozzle onto the support structure or onto the material previously deposited.