3D Printing Porous Infill Adaptation for Smooth Surfaces

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Solution Overview

Problem

Existing 3D printing methods for porous structures, particularly in medical implants, result in loose ends and rough surfaces due to orthogonal repetition of unit cells, leading to inaccuracies and potential harm to tissue during insertion.

Innovation Solution

Adapting the porous infill structure to match the circumference of the object by changing the pattern to non-orthogonal repetition, adding tracks to support ends, and optimizing track density and spacing to maintain porosity and smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If orthogonal repetition of unit cells is used for infill structure, then manufacturing simplicity is maintained, but surface smoothness and printing accuracy deteriorate due to loose ends

Engineering Contradiction:
Improveinfill structure generationVSAvoidsurface smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by transitioning from orthogonal (symmetric) repetition of unit cells to non-orthogonal arrangement of infill tracks. The tracks are positioned at angled orientations rather than strict 90-degree angles, which eliminates the loose ends problem while maintaining manufacturing simplicity through automated path planning.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent employs curvature principles by using curved or angled track paths instead of straight orthogonal lines. The infill tracks follow non-linear trajectories that adapt to the object's geometry, ensuring smooth surface termination without sharp ends that would compromise surface quality.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If orthogonal grid infill is used, then printing speed is maintained, but surface accuracy and support structure quality deteriorate

Engineering Contradiction:
Improveprinting speedVSAvoidouter surface accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the infill track orientation adaptive rather than static. The track angles and positions are dynamically adjusted based on the local geometry and curvature of the object surface, allowing the system to maintain efficient printing paths while achieving high surface accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters of the infill structure, specifically the angular orientation and spacing of tracks. By varying these parameters non-uniformly across different regions of the object, the system optimizes both printing efficiency and surface quality, avoiding the loose ends issue of orthogonal grids.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If porous infill structure is used, then material usage and printing time are reduced, but surface roughness increases due to exposed track ends

Engineering Contradiction:
Improvematerial usageVSAvoidsurface roughness
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating the treatment of infill tracks in different regions. Tracks near the object surface are positioned and oriented differently from internal tracks, with specific attention to ensuring that surface-exposed ends are properly supported and smoothed, while internal tracks maintain the porous structure for material efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs preliminary action by pre-planning the infill track paths during the slicing and support generation phase. The system anticipates where track ends will expose on the surface and pre-positioned support tracks or adjusted track orientations to prevent roughness before printing begins, ensuring smooth surfaces while maintaining porous infill benefits.

Inventive Principle:
Principle #10Preliminary action

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

The method ensures accurate, smooth, and supported ends on the outer surface of printed objects, reducing deformation and harm to tissue while maintaining intended porosity, enhancing both functionality and aesthetics.

Implementation Method 1

objects are formed by depositing multiple subsequent layers of modelling material in a controlled manner to create a desired three-dimensional (3D) object

Methodology Applied
Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 2

The modelling material can be thermally or chemically or otherwise fused with the previously deposited tracks

Methodology Applied
Scientific EffectThermal fusion: Heating

Implementation Method 3

The modelling material can be thermally or chemically or otherwise fused with the previously deposited tracks

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentEP4613461A1Three dimensional (3D) printing system and method, also printed object.
Publication Date: 2025.09.10 DEMCON BOND 3D BV
  • EP4613461A1 patent drawingFigure 1~2
  • EP4613461A1 patent drawingFigure 3~4
  • EP4613461A1 patent drawingFigure 5~6

AI summary

The disclosure relates to a method for three dimensional (3D) printing an object, the method comprising the steps of: - providing a print job, the print job comprising a representation of the object, - dividing the representation of the object in one or more bodies;- for each body, define settings for printing the respective body, wherein settings for at least one body include filling the body with a porous infill structure; - slicing the representation of the object in a number of slices, - the step of slicing comprising, for the body to be filled with the porous infill structure: - defining for every slice an infill area (64) that is to be filled with the porous infill structure; - defining a circumference (68) of the infill area; - adapting the porous infill structure to the circumference; and - filling the infill area with the adapted infill structure.