Compact Additively Manufactured Innovative Electric Motor€¦ · Eliminates extensive machining,...

National Aeronautics and Space Administration

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Compact Additively Manufactured Innovative Electric Motor

Michael C. HalbigNASA Glenn Research Center, Cleveland, OH

EnergyTech 2017, Cleveland, Ohio, October 31 to November 2, 2017.


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Outline• NASA Aeronautics Strategic Thrusts and Goals• CAMIEM intro: the objectives and approach• Limitations of conventional manufacturing• Benefits from additive manufacturing• New component designs for integration into the motor• Fabrication and evaluation of a baseline motor• Summary and next steps

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NASA Aeronautics Research Six Strategic Thrusts

Achieve and exceed N+2 and N+3 goals

for increased efficiencies and

reduced emissions.


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X-57 (Technology demonstration aircraft for reductions in fuel use, emissions, and noise)• Benefits: no in-flight emissions, low noise operation, and ~ 30% reduced

operating costs. Cruising efficiency expected to increase 3.5-5-fold.• 14 Electric Motors:• 12 low speed take-off propellers, ~14 kW electric motor for each• 2 larger wingtip propellers for cruise, ~50 kW electric motor for each

Electric Machine Stakeholders and Applications

Distributed Propulsion

NASA projects: • STARC-ABL• AATT• RVLT • SCEPTOR

STARC-ABL Vertical LiftHybrid Electric Sugar Volt

CAMIEM is currently an independent feasibility study. However, the motor class is very compatible to that of X-57.


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Objective: Utilize additive manufacturing methods to achieve new motor designs that have significantly higher power densities and/or efficiency.

Methods: • New topologies with compact designs, lightweight structures,

innovative cooling, high copper fill, and multi-material systems/components.

• Compare new components/new motor against a baseline motor.

Benefits: Eliminates extensive machining, expensive tooling and design changes, and high labor of conventional manufacturing.

Team members: NASA GRC, NASA LaRC, NASA AFRC, LaunchPointTechnologies, and the University of Texas - El Paso

CAMIEM - Compact Additively Manufactured Innovative Electric Motor

Projected Performance Specs:•6 kW at 7500 rpm, 95% efficient, 3.3 kW/kg power density (@ well below max. allowable temp.)

•10 kW at 7500 rpm, 5.5 kW/kg power density (@ max. allowable temp.)

LP Baseline Motor


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Conventional Manufacturing of Electric Motors

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Axial Flux Motor w/PCB Stator

Radial Flux Motor

www.youtube.com/watch?v=sMtQ10J1agk&nohtml5LP Conventional Axial Flux Stator

w/Litz Copper Wire Windings


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Motor Performance Metrics• Motor specific power is approximately a product of several factors

– 𝑃𝑃𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 =�𝑘𝑘𝑚𝑚∗

𝑇𝑇𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠_𝑚𝑚𝑠𝑠𝑚𝑚−𝑇𝑇𝑠𝑠𝑚𝑚𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑠𝑠𝑅𝑅𝑠𝑠𝑡𝑎𝑎𝑠𝑠𝑚𝑚𝑠𝑠𝑡𝑡

∗𝜔𝜔𝑠𝑠𝑡𝑠𝑠𝑠𝑠𝑠𝑠𝑚𝑚𝑚𝑚𝑠𝑠𝑠𝑠

• The CAMIEM sub-project will seek to make improvements to many factors:

Stator Temperature Rise• 𝑇𝑇𝑠𝑠𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠𝑠𝑠_𝑚𝑚𝑚𝑚𝑚𝑚 − 𝑇𝑇𝑚𝑚𝑚𝑚𝑎𝑎𝑠𝑠𝑠𝑠𝑎𝑎𝑠𝑠• Represents the ability of the

stator to resist heating caused by the electric current in the motor

• Increasing the max. allowable stator temp. allows higher currents and more torque from the motor

• Net thermal resistance from the stator to the ambient environment – the ultimate sink for waste heat from the motor

• Comprised of conductive and convective terms – for the baseline motor convection is much better than conduction and dominates this term

𝑹𝑹𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕𝒕Km – motor constant• Km represents the electromagnetic

efficiency of the motor at converting current into torque

• Units of torque per sqrt(power)• Making Km bigger also make the

motor larger and heavier, so to improve performance we want to make Km larger without increasing mass too much

7Mass: lighter weight materials, less volume.


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Selective Laser SinteringHigh powered laser fuses plastic, metal, or ceramic powders.

Fused Deposition ModelingPlastic or metal is heated and supplied through an extrusion nozzle and deposited.

Wire Embedding Copper wire is fed through a heated ultrasonic nozzle.

Binder Jet 3D PrintingAn inkjet-like printing head moves across a bed of powder and deposits a liquid binding material.

Direct Write PrintingControlled dispensing of inks, pastes, and slurries.

Overview of Additive Manufacturing Technologies


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Additive Manufacturing Processes Being Applied to Motor Fabrication

9Selective Laser Sintering (LaRC)

Wire Embedding (UTEP)

Binder Jet 3D Printing (GRC)

Direct Write Printing (GRC)


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LaRC: Structural Components Objective: Investigate the feasibility of attaining 1.56x improved power density over current motor design.

Approach• Identify parts with potential for significant mass reduction. • Model the baseline design and re-designed parts to determine their potential to

achieve performance improvements.• Use 3D printing for rapid prototyping and screening of design modifications.• Verify contribution of modifications to improved power density goal.

Component by Component Mass Evaluation

Form Fitted Printed Model/Prototype

Advanced Design (Housing)mass = 65 g, Aluminum 6061

63% mass savings

Performance Prediction with FEM

Advanced DesignRotor Plate

Kevlar reinforcement

PA-6, Nylon

Prototype of the baseline motor

concept redesigned with continuous

Kevlar-reinforced structure.


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UTEP: Stator with Wire EmbeddingObjectives: Investigate the feasibility for wire embedding in parts produced with material extrusion AM to yield new stator designs that have higher wire density and passive thermal management strategies.

FDM Machine 1

FDM Machine 2

CNC router capable of: • Machining• Direct-write• Wire embedding• Robotic component

placement

Six-axis robot arm (Yaskawa

MotomanMH50)

Workpiece

Sub-Element Design

Approach

Stator: 2 layers of 6 Kapton coated wire coils to be embedded Approach demonstrations with embedding and cavity forming• Embedded bondable Litz wire with material extruded above• Specimen with preformed cavities for manual introduction of

final 1.52 mm (0.06”) diameter Kapton coated wire

3 coils embedded and printed over

Quarter stator with cavities placing 0.06” Kapton coated Litz wire.

Stator design: LaunchPoint & UTEP

Brass roller

s

Motor

Wire spool

Tilt Platform

Bondable Litz wireFinal Kapton coated wire

Wire embedder

Multi3D System


www.nasa.gov12

GRC: Direct Printed StatorObjective: Investigate the feasibility for direct printing to allow for innovative stator designs that are compact and lightweight with multiple coils and iron improving magnetic flux.

Approach• Additively manufacture a stator with 3-phase coils by printing the

constituent materials: conductor, dielectric, and iron. • Evaluate silver inks, sintering methods, and carbon nanostructures

additions.

NScrypt SmartPump and Direct Write Printer Silver Conductor and Dielectric Print Layers

Printed 4-Pt Probe Winding.


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97.598

98.599

99.5100

100.5

0 200 400 600

Wei

ght %

Temperature (°C)

TGA Ag ink L16016 airConductive Silver Ink L16016 -Fraunhofer

< 3 wt.% loss

CB028, Conductive Silver

Paste - DuPont

Direct printed conductors for circuits and coils– Evaluating baseline silver inks/pastes

• Planning for inks with 250°C use temperatures• Thermogarvimetric analysis (TGA) and differential

scanning calorimetry (DSC) being conducted• Different diameter dispensing tips, oven curing, and

resulting electrical conductivity and microstructures being evaluated

• Different curing/sintering methods– Resistivity Measurements

• Printing winding patterns and conducting 4-point probe measurements

– Plan to investigate additions to inks for higher conductivity• Want electrical conductivities as good as or better than

copper wire– Also, printing relevant dielectric patterns

GRC Stator Effort - Conductive Inks

Additions of graphene and carbon nanotubes 13


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Paste Comparison of Different Vendors

PLAIN PASTE

Paste Composition Lowest Resistivity Obtained [Ωm] Conductivity [Ωm]^-1 Max Temp (*C) Vendor Resistivity

CB028 (DuPont) 2.82 x 10-8 3.54 x 107 175 7 – 10 (mΩ/sq/mil)

CL20-11127 (Heraeus) 4.37 x 10-8 2.29 x 107 300 N/A

CB100 (DuPont) 5.23 x 10-8 1.91 x 107 175 >7.5 x 10-8 Ωm

Ag-PM100 (Applied Nanotech) 9.13 x 10-8 1.10 x 107 300 >5 x 10-8 Ωm

Kapton (DuPont) 2.11 x 10-7 4.74 x 106 225


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Sample 032917-6: DuPont Silver CB028High Conductivity Silver Ink

• Nozzle 0.013”, 4 mm/s • Resistance: 0.7 Ω after 24h, 150ºC heat treat Width 969 µm ± 6.7 µm (0.04”)

Height 39 µm ± 3.1 µm (0.002”)Cross-Section

Area

25422 µm2 ± 1844 µm2(3.9 x 10-5 in2)

Resistivity 2.8 x 10-8 Ωm

969μm ~ 0.04”100 µm

Sample 71017G: Heraeus CL20-11127

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Sintering Processes

Thermal/Oven Curing

Photonic SinteringInvestigating the use for photonic sintering for printed silver inks.• Rapid post processing of conductive patterns• Few second to minute processing times without damaging/heating the substrate

Photonic Sintering for high through-put

Andreas Albrecht et all, 2016

Sebastian Wünscher et all, 2014

Electrical Resistance (Ohmic) Sintering

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LaunchPoint and AFRC: Baseline Motor Fabrication and Testing

Objective: Evaluate the full performance of a state-of-the-art axial flux motor to establish baseline electric motor performance. Approach

• LaunchPoint will fabricate 3 baseline motors and 2 controllers and conduct performance test before delivery. • AFRC will evaluate the full performance spectrum of the baseline motor in the Airvolt. Leverage X-57 cruise motor

testing.

Baseline motor with a propeller.

Motor being tested on LaunchPoint dynamometer.

Schematic of the Airvolttest stand at AFRC.

Motor

Propeller Slip Ring*

Motor Adapter

Torque / Thrust Sensor

Airvolt

Bringing experience from X-57 Cruise Motor/Airvolt

assembly and testing.

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Summary and Next StepsSummary• Additive manufacturing technologies were demonstrated to be capable of enabling

new innovative motor designs. • New component designs are being pursued for the rotor, housing, wire embedded

stator, and coil printed stator. • New designs will offer performance gains through such improvements as lighter

weights, higher coil packing, higher coil electrically conductive, higher temperature operation, and higher magnetic flux.

Next Steps • Establish the baseline motor’s performance.• Additively manufacture innovative components.• Evaluate new component performance against the baseline performance.• Determine performance and manufacturing benefits.

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Acknowledgements

Organization Name Role Organization Name Role Michael Halbig (POC) PI and GRC POC Kurt Papathakis (POC) AFRC POC and ground testing

Mrityunjay "Jay" Singh Ethan NiemenValerie Wiesner Kristen FoggDaniel Gorican Matthew Walderson

Greg Piper Patricia MartinezSteven Geng Motors and magnets Samuel Hocker Peter Kascak Electric motors Christopher Stelter

Chun-Hua "Cathy" Chuang Insulator materials Russell “Buzz” Wincheski NDEDavid Ashpis CFD and thermal analysis Stephen Hales Materials evaluation

Jeff Chin System benefits John Newman Computational materialsMichael Ricci (POC) Jose Coronel

Jon Sugar David Espalin (POC) Dave Paden Ryan Wicker

University of Texas El Paso

Stator winding and cooling efficiency

Additive manufacturing

Baseline & innovative motor designs

AM Processes/Direct printing

Additive manufacturing

Glenn Research

Center

LaunchPoint Technologies

Armstrong Flight Research

CenterElectric propulsion ground testing

Langley Research

Center

Support provided by the Convergent Aeronautics Solutions Project within the ARMD Transformative Aeronautics Concepts Program.

GRC 2017 Summer Students: Anton Salem (Washington University in St. Louis) and Jessica Zhou (Case Western Reserve University). 19

Slide Number 1OutlineSlide Number 3Electric Machine Stakeholders and ApplicationsSlide Number 5Conventional Manufacturing of Electric Motors�Motor Performance MetricsOverview of Additive Manufacturing TechnologiesAdditive Manufacturing Processes Being Applied to Motor FabricationSlide Number 10Slide Number 11Slide Number 12Slide Number 13Paste Comparison of Different VendorsSample 032917-6: DuPont Silver CB028� High Conductivity Silver InkSintering ProcessesSlide Number 17Slide Number 18Acknowledgements

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Compact Additively Manufactured Innovative Electric Motor€¦ · Eliminates extensive machining,...

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