Velocimetry Assembly for Additive Manufacturing Flow Control

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Solution Overview

Problem

Additive manufacturing systems face challenges in accurately determining and managing flow rates of molten materials during extrusion-based 3D printing, leading to variations in print quality and efficiency due to factors like liquefier scaling, material accumulation, and thermal degradation.

Innovation Solution

Incorporating a velocimetry assembly that measures and transmits flow rates of extrudate and pre-extrudate to a controller assembly, allowing for real-time compensation and calibration, and using a pulsed laser beam to detect flow rates by analyzing speckle patterns in scattered light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional extrusion-based additive manufacturing is used without flow rate monitoring, then the system structure remains simple, but print quality varies due to uncontrolled extrusion rates

Engineering Contradiction:

Improveprint qualityVSAvoidsystem structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where a velocimetry assembly continuously measures the flow rate of molten material being extruded. These measurements are fed back to the controller assembly, which adjusts the extrusion parameters in real-time to maintain consistent flow rates, thereby improving print quality through closed-loop control.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical flow control methods with optical velocimetry measurement and electronic control. Instead of relying solely on mechanical extrusion mechanisms, the system uses light-based flow rate detection and electronic actuation to precisely control material deposition, reducing mechanical complexity while improving precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If real-time flow rate monitoring is implemented using velocimetry assembly, then extrusion accuracy improves, but response time delays increase due to additional measurement and processing steps

Engineering Contradiction:

Improveflow rate determination accuracyVSAvoidresponse time delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary calibration of the velocimetry assembly before actual printing operations. During this calibration phase, the system establishes baseline flow rate measurements and control parameters. This preliminary setup enables faster real-time adjustments during printing, as the control algorithm already has pre-established reference data to work with, reducing response time delays.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If traditional extrusion control without flow monitoring is used, then the system operates quickly without additional measurement steps, but material accumulation and thermal degradation occur

Engineering Contradiction:

Improveprinting speedVSAvoidprocess consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a self-regulating extrusion system where the velocimetry assembly automatically monitors and the controller automatically adjusts extrusion parameters without external intervention. This self-service control mechanism maintains consistent material flow and temperature, preventing material accumulation and thermal degradation while preserving high printing speeds through automated real-time adjustments.

Inventive Principle:

Principle #25Self-service

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 enhances print quality and efficiency by accurately monitoring and adjusting extrusion rates, reducing response time delays and identifying potential issues like tip clogging and filament feed problems, thereby improving the consistency and speed of the 3D printing process.

Implementation Method 1

routing a pulsed laser beam toward the extrudate to scatter light rays of the pulsed laser beam from the extrudate

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

detecting at least a portion of the scattered light rays with a detector over multiple captured frames, wherein each captured frame has a speckle pattern

Methodology Applied

Scientific EffectSpeckle pattern:

Data Source

PatentUS10369776B2Additive manufacturing system and method for printing three-dimensional parts using velocimetry

Publication Date: 2019.08.06 STRATASYS INC

AI summary

An additive manufacturing system that retains a print head for printing a three-dimensional part in a layer-by-layer manner using an additive manufacturing technique, where the retained print head is configured to receive a consumable material, melt the consumable material, and extrude the molten material. The system also includes a velocimetry assembly configured to determine flow rates of the molten material, and a controller assembly configured to manage the extrusion of the molten material from the print head, and to receive signals from the velocimetry assembly relating to the determined flow rates.