Printhead Assembly Light Detection for Nozzle Malfunction

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Solution Overview

Problem

In 3D printing, improperly functioning nozzles can lead to defective products due to issues like incomplete fusion, improper droplet size, and timing, resulting in costly waste of materials and time.

Innovation Solution

The implementation of light emission devices and photon detectors mounted on the printhead allows for real-time detection of malfunctioning nozzles, enabling immediate action to stop the printing process or redirect droplets from other nozzles to prevent defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional printing processes are used without real-time detection, then the printing process is simpler and faster, but nozzle malfunctions go undetected leading to defective products and material waste

Engineering Contradiction:
Improvenozzle function reliabilityVSAvoidprinthead assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines light emission devices and photon detectors directly into the printhead assembly, merging detection functionality with the printing mechanism. This integration allows real-time monitoring of droplet ejection without adding separate external detection systems, thereby improving reliability while controlling complexity through unified design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The photon detectors provide real-time feedback on droplet ejection by detecting light from light emission devices that passes through or reflects off the droplets. This feedback loop enables immediate identification of nozzle malfunctions such as clogged nozzles or improper droplet size, allowing for timely intervention to prevent defective printing and material waste.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If real-time detection with light emission devices and photon detectors is implemented, then nozzle malfunctions are detected immediately preventing defects, but the device complexity and cost increase

Engineering Contradiction:
Improveprint quality precisionVSAvoidprinthead assembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The detection components (light emission devices and photon detectors) are integrated directly into the printhead assembly structure. This merging of detection and printing functions in a single unified component achieves real-time quality monitoring while avoiding the complexity of separate external detection systems and their associated alignment and synchronization requirements.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of substance

If continuous printing is performed without nozzle monitoring, then productivity is maintained, but defective products are produced wasting material and time

Engineering Contradiction:
Improvebuild material wasteVSAvoidprinting speed
Core Design Contradiction:
Loss of substanceVSProductivity

Solution Approach 1:

The photon detectors continuously monitor droplet ejection in real-time, providing immediate feedback on nozzle performance. When a malfunction is detected (such as a clogged nozzle or improper droplet formation), the system can instantly alert operators or automatically adjust printing parameters, preventing continued production of defective layers and minimizing build material waste while maintaining overall productivity through quick response and correction.

Inventive Principle:
Principle #23Feedback

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 reduces defects in 3D objects and minimizes material waste by allowing for real-time detection and mitigation of nozzle malfunctions during the printing process.

Implementation Method 1

A light emission device (or source) may direct a light beam across a flight path of a droplet and a detector may be positioned to receive the light beam

Methodology Applied
Scientific EffectLight absorption and transmission: Absorption (EM radiation)

Data Source

PatentEP3580042B1Printhead assembly with light emission devices and photon detectors
Publication Date: 2023.02.22 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3580042B1 patent drawingFigure 1A~1B
  • EP3580042B1 patent drawingFigure 1C~2B
  • EP3580042B1 patent drawingFigure 3

AI summary

According to examples, an apparatus may include a printhead assembly containing a housing supporting a printhead. The printhead may have nozzles that are to fire droplets of a functional agent onto a layer of build material particles along respective flight paths to form sections of a 3D object from the build material particles, an array of light emission devices to direct respective light beams in the respective flight paths, and an array of photon detectors to detect respective light beams directed from a light source of the array of light emission devices, the light emission devices and the photon detectors being supported on the housing. The apparatus may also include a controller to determine whether any of the nozzles is operating improperly based upon whether the photon detectors detected the light beams and to output an instruction regarding an improperly operating nozzle in response to a determination that the nozzle is operating improperly.