3D Printing Anti-Coalescing Gel Network for Surface Finish

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Solution Overview

Problem

In 3D printing, the use of fusing agents and laser beams can lead to unintended fusion of build material particles not intended to be part of the final object, resulting in reduced surface finish quality and accuracy due to thermal energy bleed, causing undesired fusion or semi-fusion of particles to the object's surface.

Innovation Solution

The application of an anti-coalescing polymer solution with a pendant reactive functional group and an anti-coalescing crosslinker solution forms an insoluble gel network among the build material, preventing unintended fusion by creating a removable build material portion that remains physically separated from the final object, even after energy exposure, using a process that includes selectively applying these solutions to define a removable build material portion and a remaining build material portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fusing agents and laser beams are used to form 3D objects, then material coalescence and object formation are achieved, but unintended fusion of build material particles occurs due to thermal energy bleed, reducing surface finish quality and accuracy

Engineering Contradiction:
Improvesurface finish qualityVSAvoidunintended fusion
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A liquid anti-coalescing agent is applied as an intermediary substance between the laser/fusing agent and the build material particles. This agent absorbs thermal energy from the laser beam and prevents it from reaching the build material particles, thereby eliminating unintended fusion while allowing the desired sintering process to occur. The liquid agent acts as a thermal barrier that protects adjacent particles from thermal damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If build material particles are exposed to thermal energy, then material fusion and object formation occur, but thermal energy bleed causes fusion of particles not intended to be part of the final object

Engineering Contradiction:
Improvematerial coalescenceVSAvoidobject accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The liquid anti-coalescing agent serves as a thermal intermediary that selectively blocks heat transfer to specific build material particles. By applying this agent to particles that should not fuse, the system maintains strong material coalescence in desired areas while preventing accuracy degradation from unintended fusion in adjacent areas.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The liquid anti-coalescing agent is selectively applied to specific build material particles based on the digital model requirements. This creates local variations in thermal protection, where some particles are protected from fusion while others are allowed to fuse, enabling precise control over the final object geometry and preventing accuracy loss.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If build material is supported during layer formation, then structural stability is maintained, but support material interferes with the final object and requires removal

Engineering Contradiction:
Improvestructural stabilityVSAvoidobject cleanliness
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The liquid anti-coalescing agent forms a removable protective layer around support structures and overhanging build material particles. After the 3D printing process is complete, this liquid layer can be easily removed from the final object, taking with it any attached support material or partially fused particles. This extraction process leaves the final object clean and free of support remnants without compromising the structural integrity of the main object during manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances the surface finish quality and accuracy of the final 3D object by preventing unwanted fusion, allowing for a removable object that can be separated from the final product, and maintains the insoluble gel network's integrity until a degrader solution is applied.

Implementation Method 1

the some build material in the removable build material portion reacts with a multifunctional crosslinker to form an insoluble gel network among the polymeric or polymeric composite build material in the removable build material portion

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

exposing the polymeric or polymeric composite build material to a laser beam or other radiation source to fuse the polymeric or polymeric composite build material in the patterned region

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

the fusing agent is capable of absorbing radiation and converting the absorbed radiation to thermal energy, which in turn fuses the polymeric or polymeric composite build material that is in contact with the fusing agent

Methodology Applied
Scientific EffectThermal energy conversion: Joule Heating

Implementation Method 4

the fusing agent is capable of absorbing radiation and converting the absorbed radiation to thermal energy

Methodology Applied
Scientific EffectRadiation absorption: Absorption (EM radiation)

Implementation Method 5

Some 3D printing techniques are considered additive processes because they involve the application of successive layers of material... This is unlike traditional machining processes, which often rely upon the removal of material to create the final part

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3687770B1Three-dimensional printing
Publication Date: 2023.12.27 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3687770B1 patent drawingFigure 1
  • EP3687770B1 patent drawingFigure 2A~2B
  • EP3687770B1 patent drawingFigure 2C~2E

AI summary

In an example of a method for 3D printing, a polymeric or polymeric composite build material is applied. Some of the build material is negatively patterned to define a removable build material portion and a remaining build material portion. The negatively patterning includes selectively applying an anti-coalescing polymer solution including a polymer having a pendant reactive functional group, and selectively applying an anti-coalescing crosslinker solution including a multifunctional crosslinker. The pendant reactive functional group and the multifunctional crosslinker react to form an insoluble gel network among the polymeric or polymeric composite build material in the removable build material portion. Based on a 3D object model, a layer of a final 3D object is formed from at least some of the remaining build material portion. The some of the polymeric or polymeric composite build material in the removable build material portion remains physically separated from the layer.