Coalescence Modifier for Additive Manufacturing Underhangs

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Solution Overview

Problem

Additive manufacturing machines face issues with unwanted solidification of build material due to coalescing agents, leading to degraded dimensional accuracy and surface roughness, particularly in objects with underhangs, where interlayer fusing results in excessive surface roughness.

Innovation Solution

A new additive manufacturing process is developed that uses a coalescence modifier agent as a fusion barrier applied to unpatterned build material surrounding the underhang area, preventing unwanted fusion between layers, thereby maintaining smooth and well-defined edges by inhibiting interlayer fusing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a coalescing agent is used to solidify build material in the desired pattern, then the manufacturing process can form object slices, but unwanted solidification occurs in surrounding unpatterned build material, degrading dimensional accuracy and surface roughness

Engineering Contradiction:

Improvedimensional accuracyVSAvoidunwanted solidification

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A coalescence modifier agent is applied to unpatterned build material surrounding the patterned area. This modifier agent acts as an intermediary substance that prevents the coalescing agent from causing unwanted solidification in the surrounding build material, while allowing the desired patterned areas to solidify properly. The modifier agent is applied before the coalescing agent to establish a protective barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The build material is treated with different agents in different locations: the coalescing agent is applied only to the desired pattern areas to promote solidification, while the coalescence modifier agent is applied to surrounding unpatterned areas to prevent unwanted solidification. This localized differentiation of treatment resolves the contradiction between achieving complete solidification and preventing unwanted solidification.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If heat is generated in patterned build material to coalesce and solidify it, then object slices can be formed, but heat propagates into surrounding unpatterned build material causing unwanted solidification

Engineering Contradiction:

Improveedge definitionVSAvoidheat propagation

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The coalescence modifier agent serves as a thermal barrier between the heated patterned build material and the surrounding unpatterned build material. When the coalescing agent generates heat to coalesce the patterned areas, the modifier agent in the surrounding areas prevents this heat from propagating and causing unwanted solidification, thereby protecting edge definition.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If build material in overlying layers is heated to form slices, then the object can be built layer by layer, but interlayer fusing occurs in underhang areas resulting in excessive surface roughness

Engineering Contradiction:

Improvelayer formation rateVSAvoidsurface roughness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The coalescence modifier agent is applied to unpatterned build material in advance, before the heating and coalescence process occurs. This preliminary application ensures that when heat is later applied to form slices in overlying layers, the modifier agent is already in place to prevent interlayer fusing in underhang areas, thereby preventing excessive surface roughness while maintaining productivity.

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

This process effectively controls unwanted fusing between build material layers, enhancing the dimensional accuracy and surface smoothness of 3D objects with underhangs by preventing the coalescence of build material in the underhang areas, resulting in improved edge definition and reduced surface roughness.

Implementation Method 1

a light absorbing ink or other suitable coalescing agent is 'printed' on to a layer of build material in the desired pattern and then exposed to light to coalesce the patterned build material

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

Coalescing agents increase light absorption to generate sufficient heat to sinter, melt or otherwise coalesce the patterned build material

Methodology Applied

Scientific EffectPhotothermal conversion: Absorption (EM radiation)

Implementation Method 3

Modifier agents have been developed to block or neutralize the effects of a coalescing agent. The unwanted solidification of build material may be controlled by dispensing a coalescence modifier agent on to unpatterned build material surrounding build material patterned with a coalescing agent

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS20210370597A1Additive manufacturing

Publication Date: 2021.12.02 PERIDOT PRINT LLC

AI summary

In one example, a non-transitory processor readable medium with instructions thereon that when executed cause an additive manufacturing machine to inhibit build material in an overlying layer of build material from fusing with a first slice formed in an underlying layer of build material.