Halftoning Threshold Control for Uniform 3D Print Energy

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Solution Overview

Problem

Additive manufacturing devices face non-uniform energy delivery due to variations in components and nozzle dispense volumes, leading to defects in 3D objects such as coalescence issues, poor surface properties, and limited build area utilization.

Innovation Solution

A system and method for adjusting halftoning thresholds to compensate for spatial energy variations and nozzle dispense variations, using a threshold manager with engines to determine actual energy values, assign reference and relative energy values, and adjust halftoning thresholds to ensure uniform energy delivery across the build area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If additive manufacturing devices use standard halftoning methods with fixed thresholds, then the manufacturing process is simple and fast, but energy delivery becomes non-uniform causing defects in 3D objects

Engineering Contradiction:
Improveenergy delivery uniformityVSAvoidhalftoning threshold adjustment system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by adjusting halftoning thresholds based on spatial location within the build area. Different locations have different threshold values to compensate for non-uniform energy delivery. The system determines actual energy values at various locations and assigns location-specific thresholds, ensuring each region receives appropriate energy for proper material coalescence and object quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements feedback by measuring or determining actual energy values delivered to different locations in the build area, then using this information to adjust halftoning thresholds. The system continuously monitors energy delivery characteristics and modifies threshold values accordingly, creating a closed-loop control system that maintains uniform energy delivery across the build area.

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If additive manufacturing devices operate with standard halftoning thresholds, then the process is fast and simple, but build area utilization is limited due to non-uniform energy delivery

Engineering Contradiction:
Improvebuild area utilizationVSAvoidobject quality
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent enables broader build area utilization by applying location-specific halftoning thresholds that compensate for energy delivery variations across different regions. This allows the system to effectively use the entire build area including regions that would otherwise be problematic, expanding the usable build volume while maintaining object quality through localized threshold adjustments.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If additive manufacturing devices use fixed halftoning thresholds, then nozzle dispense variations do not need compensation, but object quality suffers due to non-uniform energy delivery

Engineering Contradiction:
Improveobject qualityVSAvoidthreshold adjustment mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the halftoning threshold parameter based on spatial location and energy delivery characteristics. Instead of using a fixed threshold, the system dynamically adjusts threshold values according to actual energy values at different locations, compensating for both energy delivery non-uniformity and nozzle dispense variations. This parameter adaptation ensures consistent object quality across the entire build area.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If additive manufacturing devices deliver non-uniform energy, then the manufacturing process is simpler, but defects such as poor coalescence and surface properties occur

Engineering Contradiction:
Improvecoalescence qualityVSAvoidenergy delivery control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses feedback control to monitor actual energy delivery at different locations and adjust halftoning thresholds accordingly. This ensures that each region receives the appropriate energy level for proper material coalescence, eliminating defects caused by non-uniform energy delivery while maintaining a relatively simple manufacturing process through software-based threshold adjustment.

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 approach results in consistent energy delivery, improved object quality, increased build area utilization, and the ability to manufacture larger 3D objects with enhanced accuracy and surface properties.

Implementation Method 1

determining an actual energy value of a first location of a plurality of locations of a build area... assign a relative energy value to a second location of the plurality of locations based on the reference energy value

Methodology Applied
Scientific EffectEnergy absorption: Absorption (EM radiation)

Data Source

PatentEP3250999B1Adjustment of a halftoning threshold
Publication Date: 2023.03.01 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3250999B1 patent drawingFigure 1
  • EP3250999B1 patent drawingFigure 2
  • EP3250999B1 patent drawingFigure 3

AI summary

Adjustment of a halftoning threshold can, in an example implementation, include assigning a relative energy value, relative to a reference energy value, to a location of a build area and adjusting a halftoning threshold based on the relative energy value.