3D Printed Surface Dithering for Staircasing and Thickening

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Solution Overview

Problem

Three-dimensional printing technologies face challenges in reproducing the shape and appearance of objects accurately due to quantization errors leading to staircasing artifacts and material thickening, which affect the durability and visual quality of printed objects.

Innovation Solution

A method involving surface dithering and erosion steps is employed to modify the surface of 3D printing objects, using spatially high-frequent dithering signals to reduce low-frequency quantization errors and correct thickening effects, resulting in smoother and more durable prints without the need for costly post-processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If voxel-based 3D printing is used to achieve material placement precision, then manufacturing capability is improved, but quantization errors cause staircasing artifacts that worsen surface quality

Engineering Contradiction:
Improvematerial placement precisionVSAvoidsurface quality
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The patent applies preliminary action by performing erosion and dithering operations on the 3D model data before the actual printing process. The erosion step预先 removes material from the digital model to compensate for expected thickening, while dithering pre-modifies surface geometry to prevent staircasing artifacts, both actions taken in advance to counteract known printing defects

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by modifying the digital model parameters (surface geometry, voxel classification) through erosion and dithering algorithms. The erosion changes the effective surface position by removing layers, while dithering modifies surface normals and voxel assignments to eliminate quantization errors, transforming the model parameters to compensate for printing process imperfections

Inventive Principle:
Principle #35Parameter changes

2Strength

If material is deposited to ensure structural integrity with overlap between voxels, then strength is improved, but thickening effect worsens geometric accuracy

Engineering Contradiction:
Improvestructural integrityVSAvoidgeometric accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies preliminary anti-action by performing erosion on the digital model before printing to counteract the expected thickening effect. The erosion removes material in advance from the model geometry, creating a compensatory deficit that will be filled by the inevitable material overlap and thickening during the printing process, thereby restoring geometric accuracy

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses inversion by reversing the normal approach: instead of adding material to ensure structural integrity and then removing excess through post-processing, the method first removes material through erosion in the digital model, then allows material accumulation during printing to achieve both structural integrity and geometric accuracy simultaneously

Inventive Principle:
Principle #13The other way round (Inversion)

3Shape

If mechanical post-processing is applied to remove staircasing artifacts, then surface quality is improved, but manufacturing cost and time increase

Engineering Contradiction:
Improvesurface qualityVSAvoidmanufacturing cost and time
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for mechanical post-processing by performing preliminary dithering and erosion operations on the digital model before printing. These computational operations pre-correct surface geometry and compensate for thickening effects, achieving smooth surfaces and accurate dimensions directly in the printed object without requiring subsequent mechanical intervention

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent substitutes mechanical post-processing operations (sanding, polishing) with computational operations (erosion, dithering) performed in the digital domain. The mathematical algorithms modify the model data to pre-compensate for defects, replacing physical mechanical processes with digital signal processing and morphological operations

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4092560A1A method for three-dimensional printing with surface dithering, a computer program product and a 3D printing device
Publication Date: 2022.11.23 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4092560A1 patent drawingFigure 1
  • EP4092560A1 patent drawingFigure 2
  • EP4092560A1 patent drawingFigure 3

AI summary

The invention relates to a method for three-dimensional printing, a computer program product and a 3D printing device, wherein a method for three-dimensional printing comprises the steps of • dithering a set surface (9) of the printing object (7), • printing the printing object (7) with the dithered surface, wherein the dithering step (S1) comprises • determining the set surface (9) of the printing object (7), • providing a spatially high-frequent dithering signal, • modifying the set surface (9) as a function of the dithering signal.