Error Diffusion in 3D Contone Model Data for Additive Manufacturing

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Solution Overview

Problem

In additive manufacturing, the migration of heat or reactive chemical species between layers can lead to reduced dimensional accuracy and flaws due to undesired material curing, melting, or reacting in additive manufacturing processes, resulting from energy or reactant diffusion.

Innovation Solution

A method and system that generate halftone data for slices of a three-dimensional model, incorporating compensatory error values to adjust for errors in successive slices, using a processor, error diffusion module, and halftoning module to ensure precise deposition of build material and energy application, mitigating the effects of heat and chemical bleeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If halftone data is generated for successive slices without error compensation, then processing speed is maintained, but dimensional accuracy deteriorates due to heat and chemical diffusion between layers

Engineering Contradiction:
Improvedimensional accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by calculating compensatory error values for each slice before the actual additive manufacturing process. The system pre-computes error diffusion data based on halftone algorithms and stores it in a lookup table, so that when manufacturing begins, the pre-calculated compensation values are simply applied to each slice. This eliminates the need for complex real-time calculations during manufacturing, maintaining processing speed while improving dimensional accuracy through pre-applied error compensation.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If error diffusion compensation is applied to successive slices, then manufacturing precision improves, but computational time and processing complexity increase

Engineering Contradiction:
Improvedimensional accuracyVSAvoidcomputational time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs error diffusion calculations in advance during a preprocessing stage, generating compensatory error values that are stored for later use. This preliminary computation separates the complex mathematical operations from the actual manufacturing process, allowing the manufacturing phase to proceed quickly by simply applying pre-computed values to each slice, thus reducing computational time during production.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a lookup table approach where pre-calculated error compensation values are stored and then copied/applied to corresponding slices during manufacturing. Instead of performing complex calculations for each slice in real-time, the system retrieves and applies stored compensation patterns, significantly reducing computational overhead while maintaining the precision benefits of error diffusion.

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If halftoning is applied to reduce heat diffusion effects, then manufacturing precision improves, but the complexity of the data processing system increases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidhalftoning system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the error compensation process into distinct components: halftone matrix generation, error value calculation, and slice-by-slice application. Each slice is processed independently with its own error compensation values, allowing the complex halftoning algorithm to be broken down into manageable steps that can be implemented systematically without overwhelming system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary lookup table that stores pre-calculated error compensation values between the halftoning algorithm and the actual manufacturing process. This intermediary structure simplifies the interface between the complex halftoning computation and the straightforward manufacturing execution, allowing the complex logic to be encapsulated in the lookup table generation while keeping the manufacturing process simple and efficient.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 prevents flaws in dot patterning and improves the homogeneity of the three-dimensional object by adjusting energy and material application, reducing the impact of heat and chemical diffusion, resulting in enhanced dimensional accuracy and reduced structural defects.

Implementation Method 1

the migration of heat or reactive chemical species between layers can lead to reduced dimensional accuracy and flaws due to undesired material curing, melting, or reacting in additive manufacturing processes, resulting from energy or reactant diffusion

Methodology Applied
Scientific EffectHeat diffusion: Conduction (thermal)

Implementation Method 2

the migration of heat or reactive chemical species between layers can lead to reduced dimensional accuracy and flaws due to undesired material curing, melting, or reacting in additive manufacturing processes, resulting from energy or reactant diffusion

Methodology Applied
Scientific EffectChemical diffusion: Diffusion

Data Source

PatentEP3204921B1Diffusing an error in three-dimensional contone model data
Publication Date: 2020.10.07 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3204921B1 patent drawingFigure 1
  • EP3204921B1 patent drawingFigure 2
  • EP3204921B1 patent drawingFigure 3

AI summary

A method of diffusing an error in three-dimensional contone model data includes generating halftone data for a slice among a number of slices of the three-dimensional contone model data, generating compensatory error values based on the generated halftone data, and adding the generated compensatory error values to contone data for a successive slice.