Laser Power Determination for Selective Sintering

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Solution Overview

Problem

Conventional selective laser sintering methods using high laser power result in inconsistent manufacturing of PAEK polymer parts due to batch-to-batch variations in powder characteristics, leading to incomplete fusion, porosity, and reduced tensile strength.

Innovation Solution

A method to analytically determine an optimal laser power setting for each batch of powder by testing multiple test rods at varying power levels, inspecting for voids and tensile strength, and selecting the power that achieves the highest Z-axis strength without voids, typically within the range of 1 W to 10 W for PEKK polymer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high laser power is used for sintering PAEK polymer powder, then the sintering process can be completed faster, but the manufacturing precision deteriorates due to porosity and incomplete fusion

Engineering Contradiction:
Improvesintering speedVSAvoidfusion quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by systematically varying laser power settings across multiple test rods (different powers within the range of 1 W to 10 W) to identify the optimal parameter range that achieves complete fusion without porosity. This resolves the contradiction by finding a power range that maintains both productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by adjusting laser power dynamically based on the specific batch of powder material being used. Rather than using a fixed high power setting, the system adapts the laser power to match the characteristics of each powder batch, ensuring optimal fusion quality while maintaining efficient sintering speed.

Inventive Principle:
Principle #15Dynamics

2Reliability

If high laser power is used to ensure complete fusion, then the sintering effectiveness improves, but the tensile strength deteriorates due to porosity formation

Engineering Contradiction:
Improvefusion completenessVSAvoidtensile strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses parameter changes to identify and apply the optimal laser power range (1 W to 10 W) that achieves complete fusion without creating porosity. By systematically testing different power levels and selecting the range that produces dense, pore-free structures, the patent simultaneously achieves high fusion completeness and high tensile strength.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a fixed laser power setting is used for all powder batches, then the operation simplicity is improved, but the manufacturing precision deteriorates due to batch-to-batch variations

Engineering Contradiction:
Improveoperational simplicityVSAvoidconsistency across batches
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by determining the optimal laser power range (1 W to 10 W) in advance through systematic testing with test rods before actual production. This pre-characterization of the optimal parameter range allows for consistent, high-precision manufacturing across different powder batches while maintaining operational simplicity.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If laser power is increased to reduce porosity, then the structural integrity improves, but the energy consumption increases

Engineering Contradiction:
Improvestructural integrityVSAvoidlaser energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by identifying and implementing the optimal laser power range (1 W to 10 W) that achieves complete fusion and high structural integrity without excessive energy consumption. This optimized parameter range eliminates porosity and ensures strong structures while using significantly less energy than conventional high-power sintering methods.

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

This approach ensures consistent and strong tensile strength in manufactured parts, with Z strength greater than 7 KSI, and reduces porosity, achieving structural integrity and uniformity.

Implementation Method 1

The laser selectively fuses the powder material by scanning cross-sectional layers generated from a three-dimensional digital description of the desired object onto the top layer or surface of a bed of powder material. The powder must absorb enough laser energy to reach a fusing state necessary for bonding between powder particles.

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

The laser selectively fuses the powder material by scanning cross-sectional layers... The powder must absorb enough laser energy to reach a fusing state necessary for bonding between powder particles.

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

Preheating may be accomplished by heating the actual bed, which transfers energy to the powder in the form of heat via thermal conduction.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

Preheating is also provided via radiant heaters disposed above the bed surface.

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3593999B1Method of analytically determining laser power for sintering
Publication Date: 2022.05.04 HEXCEL CORP
  • EP3593999B1 patent drawingFigure 1
  • EP3593999B1 patent drawingFigure 2
  • EP3593999B1 patent drawingFigure 3

AI summary

A method of analytically determining an optimal laser power for configuring a laser in a selective laser sintering process, comprising: choosing a batch of powder material for building a plurality of test rods (202a-202e); selecting a range of laser power for building the plurality of test rods (202a-202e); determining a plurality of power increments within the selected range to define a plurality of different laser power settings; programming a selective laser sintering machine (10) to build at least one test rod of said plurality of test rods (202a-202e) at each laser power setting; constructing the plurality of test rods (202a-202e) from the batch of powder material (36) based on said programming; inspecting each test rod for voids in a surface of the test rod; and identifying the laser power setting used to construct a respective test rod without formation of voids in the surface as an optimal laser power for configuring the selective laser sintering machine (10) when conducting a laser sintering process using the chosen batch of powder material (36).