Jet Print Head with Piezoelectric Capillary for 3D Surface Alignment

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Solution Overview

Problem

Current jet printing technologies face limitations in aligning print heads with three-dimensional surfaces, require complex cleaning processes, and struggle with cross-contamination when changing fluids, especially in aerosol jet and ultrasonic dosing methods, which affect the consistency and quality of printed structures.

Innovation Solution

A jet print head design featuring a capillary with a nozzle opening that forms an aerosol directly at the nozzle with an axial oscillating movement, using a piezoelectric actuator connected to the capillary, allowing for flexible alignment and reduced dead volume, along with a guide gas that forms an aerosol just before printing, enabling efficient aerosol formation and regulation without mechanical decoupling or additional cleaning steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If aerosol jet printing uses separate subsystems for aerosol generation and print nozzle, then aerosol can be generated and transported, but the print head cannot be arbitrarily aligned with the surface to be printed and requires complex piping systems

Engineering Contradiction:
Improvealignment flexibilityVSAvoidpiping system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the aerosol generation chamber and the print nozzle into a single integrated print head unit. The piezoelectric actuator directly drives a capillary nozzle, eliminating the need for separate aerosol generation and transport subsystems. This integration allows the print head to be freely aligned with the substrate surface without requiring complex piping systems or mechanical decoupling mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If aerosol is conveyed through long piping lines, then aerosol generation and printing can be separated, but droplet size changes due to agglomeration and droplet deposition on walls occur

Engineering Contradiction:
Improveprocess separabilityVSAvoiddroplet size consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The piezoelectric actuator generates aerosol droplets directly at the nozzle tip through ultrasonic vibration, eliminating the need for long-distance aerosol transport. The aerosol is formed and deposited in a single location, preventing droplet agglomeration and wall deposition that would otherwise occur during extended conveyance through piping systems.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If mechanical ink collection device is used to create breaks in printed image, then printing can be interrupted, but the device becomes more complex and requires additional components

Engineering Contradiction:
Improveprinting controlVSAvoidmechanical components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical ink collection devices with electronic control of the piezoelectric actuator. By controlling the activation and deactivation of the ultrasonic vibration, the system can start and stop aerosol generation electronically, creating breaks in the printed image without requiring any mechanical interruptors or collection devices.

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 allows for precise printing on three-dimensional structures with reduced contamination and easier fluid changes, improving the homogeneity and quality of printed images by regulating aerosol flow and droplet size through adjustable process parameters, and eliminating the need for mechanical ink catchers or complex cleaning processes.

Implementation Method 1

a vibration actuator, in particular a piezoelectric element (10), which moves the capillary (4) back and forth in an axial direction

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The capillary (4), preferably a glass capillary, is connected to at least one reservoir (12) for the fluid (pressurized fluid)

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 3

A guide gas is introduced into the prechamber around the capillary via the at least one inlet opening (11) and mixes with the fluid droplets (14) in the prechamber (8) to form an aerosol stream

Methodology Applied
Scientific EffectGas-liquid mixing:

Implementation Method 4

The liquid or paste is continuously separated and atomized as fluid droplets (14) at the nozzle opening (5)

Methodology Applied
Scientific EffectAtomization:

Implementation Method 5

The suspension of the capillary (4) in the printhead housing (1) comprises at least one elastic element (7), at least one actuator (10)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3752365B1Print head and printing method
Publication Date: 2023.08.09 KARLSRUHER INST FUR TECH
  • EP3752365B1 patent drawingFigure 1a
  • EP3752365B1 patent drawingFigure 1b
  • EP3752365B1 patent drawingFigure 2a~2e

AI summary

Print head, comprising a capillary (4) which adjoins at least one elastic element (7) around an axis of symmetry (3) for a liquid to be printed with a nozzle opening (5) which opens into a pre-chamber (8), wherein the pre-chamber has an outlet opening (2), which is aligned with respect to the nozzle opening of the capillary in its axial orientation of the axis of symmetry (3), and at least one inlet opening (11) for a guiding gas (13), the at least one elastic element forms a guide for the capillary only in its axial orientation, and feeding means (12) for the liquid to be printed into the capillary are provided. The problem consists in proposing a print head which is particularly suitable for printing even three-dimensional structures. The problem is solved by way of a print head, wherein a mechanical vibration system is provided comprising the at least one elastic element (7) and the capillary (4) with the liquid which is contained therein, and an actuator (10) with a mechanical or magnetic interaction of force with the vibration system is provided.