Capacitive Detector for Extrusion Tip Clogging

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Solution Overview

Problem

Extrusion-based digital manufacturing systems face challenges in detecting consumable materials and identifying compositional properties, particularly in preventing tip clogging during liquefier purges, which can disrupt the 3D modeling process.

Innovation Solution

A capacitive detector system is integrated into the manufacturing system, using excitation and sense conductive components to generate electrical fields and sample capacitive values, allowing for the detection of consumable materials and compositional properties, such as moisture concentrations, and identifying loss of extrusion events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional detection methods are used for consumable materials, then the system structure remains simple, but the ability to detect compositional properties and prevent tip clogging is insufficient

Engineering Contradiction:

Improvetip clogging preventionVSAvoiddetector structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical detection methods with a capacitive detection system that uses electrical fields to detect consumable material properties. The excitation conductive component generates an electrical field that interacts with the consumable material, and the sense conductive component measures capacitive changes, enabling non-contact detection of compositional properties like moisture content without mechanical contact or complex mechanical structures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electrical field as an intermediary between the detector and the consumable material. The excitation conductive component creates an electrical field that penetrates the consumable material, and the sense conductive component detects capacitive changes caused by the material's composition. This intermediary field enables indirect measurement of compositional properties without direct physical contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If no detection system is used, then the device complexity is low, but the measurement precision of consumable material properties cannot be achieved

Engineering Contradiction:

Improvecompositional property detectionVSAvoiddetector system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs capacitive sensing technology that uses electrical field interactions to measure compositional properties of consumable materials. The system measures capacitance changes between the excitation and sense conductive components, which vary according to the material's dielectric properties, moisture content, and composition, providing precise non-contact measurement without mechanical sensors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent detects compositional properties by measuring changes in capacitive parameters. As the consumable material's composition, moisture content, or density changes, the capacitance between the excitation and sense conductive components changes accordingly. The system monitors these capacitive parameter variations to identify material properties and detect anomalies.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If continuous monitoring is implemented, then the reliability of the 3D modeling process is improved, but the energy consumption increases

Engineering Contradiction:

Improvecontinuous operation assuranceVSAvoiddetector energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic sampling of capacitive values rather than truly continuous monitoring. The system periodically measures the capacitance between the excitation and sense conductive components at defined intervals during the extrusion process. This periodic measurement approach provides sufficient monitoring for reliability while reducing energy consumption compared to truly continuous high-frequency sampling.

Inventive Principle:

Principle #19Periodic action

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

The capacitive detector effectively detects the presence of extrudates and compositional properties, preventing tip clogging and ensuring continuous operation by accurately identifying material presence and composition, thus maintaining the integrity of the 3D modeling process.

Implementation Method 1

The excitation conductive component is configured to generate an electrical field with the sense conductive component... a processor configured to compare capacitive values of sampled signals operably received from the sense conductive component

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The excitation conductive component is configured to generate an electrical field with the sense conductive component

Methodology Applied

Scientific EffectElectrical field: Electric Field

Data Source

PatentUS8222908B2Capacitive detector for use in extrusion-based digital manufacturing systems

Publication Date: 2012.07.17 STRATASYS INC

AI summary

A detector for use in an extrusion-based digital manufacturing system, the detector comprising a sense conductive component and an excitation conductive component to define a first gap that is configured to receive a consumable material used in the extrusion-based digital manufacturing system, where the excitation conductive component is configured to generate a first electrical field across the first gap.