Nucleated Polymer Particles for Warp-Resistant SLS Printing

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Solution Overview

Problem

Selective laser sintering (SLS) in additive manufacturing is limited by the lack of functional materials and warping issues, particularly with polymers like polypropylene, which have low crystallization temperatures leading to non-planar layers during cooling.

Innovation Solution

The use of thermoplastic polymer particles incorporating a nucleating agent, produced through melt emulsification, maintains a similar crystallization temperature and reduces warping by forming highly spherical particles with controlled crystallization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If thermoplastic polymers with low crystallization temperature (like polypropylene) are used in SLS, then material versatility is improved, but warping occurs during cooling leading to non-planar layers

Engineering Contradiction:

Improvematerial versatilityVSAvoidlayer planarity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent modifies the crystallization temperature parameter of the thermoplastic polymer by adding nucleating agents. This shifts the crystallization temperature from below the sintering temperature to above it, preventing warping while maintaining material versatility. The nucleating agents change the thermal parameters of the polymer to resolve the contradiction between using low-crystallization-temperature materials and maintaining layer planarity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining thermoplastic polymers with nucleating agents. This composite approach allows the polymer to maintain its desirable processing characteristics while the nucleating agent provides the necessary crystallization control to prevent warping, thus resolving the contradiction between material versatility and manufacturing precision.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If process conditions are controlled to prevent warping, then manufacturing precision is improved, but process complexity increases

Engineering Contradiction:

Improvewarping controlVSAvoidprocess condition control

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by incorporating nucleating agents into the polymer particles before the SLS process. This pre-modification ensures that crystallization occurs at the correct temperature during sintering, automatically preventing warping without requiring complex real-time process control. The warping prevention is built into the material itself rather than relying on complex process management.

Inventive Principle:

Principle #10Preliminary action

3Duration of action of stationary object

If additional time is allowed for cooling and crystallization, then complete crystallization is achieved, but warping increases due to temperature differences in the build chamber

Engineering Contradiction:

Improvecrystallization timeVSAvoidwarping

Core Design Contradiction:

Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent changes the crystallization temperature parameter to occur above the sintering temperature. This eliminates the problematic time window where the polymer would crystallize at low temperatures causing warping. Crystallization now occurs quickly at high temperature when the entire build chamber is uniformly hot, preventing warping even though sufficient time is allowed for complete crystallization.

Inventive Principle:

Principle #35Parameter changes

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 mitigates warping in SLS by maintaining the crystallization temperature of thermoplastic polymers, enhancing flow characteristics and consolidation, and improving the accuracy of 3D printed objects.

Implementation Method 1

the nucleating agent may, advantageously, increase the crystallization temperature of the thermoplastic polymer

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 2

polymer particles that comprise a thermoplastic polymer and a nucleating agent

Methodology Applied

Scientific EffectNucleation: Nucleation

Implementation Method 3

Selective laser sintering (SLS) is a type of three-dimensional (3-D) printing, also known as additive manufacturing, that produces plastic parts by using a laser to sinter consecutive layers of polymeric powder

Methodology Applied

Scientific EffectSelective laser sintering: Selective Laser Sintering

Data Source

PatentUS12534627B2Polymer particles and related additive manufacturing methods

Publication Date: 2026.01.27 XEROX CORP

AI summary

Polymer particles that comprise a thermoplastic polymer and a nucleating agent may be useful in additive manufacturing methods where warping may be mitigated. For example, a method of producing sais polymer particles may comprise: a thermoplastic polymer, a nucleating agent, a carrier fluid, and optionally an emulsion stabilizer at a temperature at or greater than a melting point or softening temperature of the thermoplastic polymer to emulsify a thermoplastic polymer melt in the carrier fluid; cooling the mixture to form polymer particles; and separating the polymer particles from the carrier fluid, wherein the polymer particles comprise the thermoplastic polymer, the nucleating agent, the emulsion stabilizer, if included, and wherein the polymer particles have a crystallization temperature that is substantially the same as a crystallization temperature of the thermoplastic polymer prior to mixing.