3D Printing: Can it work for lighting? - lrc.rpi.edu · – Binder jetting (BJ) • Powder bed and...

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2019 Annual ConferenceAugust 8 -10 | Omni Louisville Hotel | Louisville, KY

3D Printing: Can it work for lighting?Nadarajah Narendran, PhD Professor/Director of Research, Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY

Indika U. Perera, PhDResearch Scientist, Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY

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Learning Objectives

Participants will be able to:1. Identify……………2. Compare……………….3. Describe……………4. Analyze…………….

3D Printing: Can it work for lighting?

Learning Objectives

Participants will be able to:1. Compare the 3D printing processes available today.2. Identify what fixture components can be made with today’s print

technologies.3. Analyze the performance of 3D-printed components compared to the

performance of components made using traditional methods. 4. Describe the impact of 3D printing on businesses.

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IES presentation outline

This presentation will cover the state-of-the-art of 3D printing for lighting, including recent research on the ability of current print materials, 3D printers, and different additive manufacturing methods to create the optical, thermal, and electrical components required by lighting systems. The presenters will share results from laboratory studies conducted at Rensselaer’s Lighting Research Center on the use of 3D printing to create lighting components. In addition, the presentation will discuss the impact 3D printing will have on business.

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Press

3D PRINTING: CAN IT WORK FOR LIGHTING?

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What is 3D printing?

• 3D printing is a process by which 3D objects are formed by the addition of materials, one layer at a time.

– This process is also known as additive manufacturing (AM)

– Material is deposited via a printhead or a nozzle or other types of AM processes

http://edition.cnn.com/TECH/specials/make‐create‐innovate/3d‐printing/

Reference:1. Excell, Jon. "The rise of additive manufacturing". The Engineer. Retrieved 2013‐10‐30.2. https://en.wikipedia.org/wiki/3D_printing

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3D printing processes

• ASTM F2792-12a, ISO 17296-1 classify 7 distinct processes

– Vat photopolymerization (VP)• Stereolithographic (SLA)• Digital light processing (DLP)

– Material extrusion (MX)• Fused deposition modeling (FDM)• Fused filament fabrication (FFF)• Continuous fiber fabrication (CFF)

– Material jetting (MJ)• Multi-jet modeling (MJM)• Drop-on-Demand (DoD)

– Direct energy deposition (DED)• Laser metal deposition (LMD)

– Powder bed fusion (PBF)• Electron beam melting (EBM)• Selective laser sintering (SLS)• Selective heat sintering (SHS)• Direct metal laser sintering (DMLS)• Multi-jet Fusion (MJF)

– Binder jetting (BJ)• Powder bed and inkjet head 3D printing (PBIH)• Plaster-based 3D printing (PP)

– Sheet lamination• Ultrasonic consolidation (UC)• Laminated object manufacturing (LOM)

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3D printing processes and material

Polymer Metal

Ceramic

Material jettingDirect energy deposition

Vat photopolymerizationMaterial extrusionBinder jetting

Powder bed fusionSheet lamination

Source: Adopted from IDTechEx 2018, Masterclass 7 handoutshttp://www.3ders.org/articles/20170524‐sculpteos‐newly‐released‐state‐of‐3d‐printing‐2017‐report‐shows‐a‐maturing‐market.html

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Rapid adoption of 3D printing by many industries

Source: Wohlers Associates, 2014

3D printing contribution by industry

3D‐printed parts for the Rolls‐Royce Phantom. (Image source: bmw.com)

3D‐printed hearing aid (Image source: forbes.com)

3D printing technology shakes up parts production for automakers

CFM International’s 3D‐printed fuel nozzle reduces part count from 18 to just 1. (Image source: ge.com)/

Aerospace giant embraces 3D printing for flight‐ready parts

3D Printing Is Already Changing Health Care

Customizable 3D‐printed electric shavers (Image source: 3dprint.com)

Adidas Plans To Bring 3D Printing To The Masseshttps://www.forbes.com/

3D Printing to Unlock Consumer Personalization

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Why 3D printing for lighting?

Problem: Price erosion and quality of fixtures– LEDs are becoming a commodity item– Majority of LED light fixture manufacturing has moved overseas– LED lighting fixture prices are rapidly decreasing and US manufacturers are looking at ways to

reduce manufacturing cost while not compromising quality

Potential solution: 3D printing; Mass customization rather than Mass production • Value proposition

– Custom fixtures that better match with the built environments improves visual appeal and functions

• Reduced cost custom fixtures– Reduced carbon footprint, manufactured close to construction site– Reduced manufacturing cost by reducing integration steps– Reduced storage

• Rapid fixture design change– Easy to change fixture design

On‐site, on‐demand manufacturing of cost competitive custom light fixtures

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Opportunity

Building design Construction Interior finishing

Custom lighting fixture design

On-site 3D printingof fixture

Interior lighting with custom fixtures

Vision: Change Architectural Lighting Practice

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Current

ArchitectureManufacture

Product Design & Specification

TransportStorage Shipping Storage Transport

Product manufacturing

ArchitectureStorage Transport

Product design andManufacture

On‐site

Present

Future

3D printing can change the supply chain for LED light fixture

Impact• Increase local manufacturing and jobs• Reduced carbon footprint• Better quality, custom light fixtures

Mass Production to Mass Customization

With Additive Manufacturing

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3D printed light fixtures

• Some manufacturers are already marketing 3D printed light fixtures– Mostly decorative fixtures

https://www.designboom.com/design/gantri‐3d‐printing‐bring‐designer‐lights‐life‐11‐02‐2017/

https://all3dp.com/1/3d‐printed‐lamp‐lampshades‐3d‐printed‐light/

https://lucept.com/2019/05/21/signifys‐3d‐printed‐mycreation‐series/

3DPrinting.Lighting_Philips Lighting Telecaster_decodownlight_illuminated

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Market size for 3D printing and lighting fixture industries

• 3D printing industry expected to grow above $21 billion by 2020.• Lighting fixture market expected to grow above $35 billion by 2020.

https://www.computerworld.com/article/3066862/emerging‐technology/3d‐printing‐industry‐to‐triple‐in‐four‐years‐to‐21b.html

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Understanding the needs for printing light fixtures

• Feasibility assessment– To investigate if functional lighting

fixture components can be fabricated using current 3D printing technologies and materials:

• Thermomechanical • Electrical• Optical

Light Fixture

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Mechanical Components

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Processes Technologies Materials Claimed advantages Claimed disadvantages

Vat polymerization SLA, DLP Liquid photopolymer, composites

Complex and detailed geometry compared to FDM

Post-processing; require support structure; limited material

Potential 3D printing processes

• Mechanical and Electrical components

• Optical components

Source: https://dupress.deloitte.com/dup‐us‐en/focus/3d‐opportunity/the‐3d‐opportunity‐primer‐the‐basics‐of‐additive‐manufacturing.html and http://www.lboro.ac.uk/research/amrg/about/

Processes Technologies Materials Claimed advantages Claimed disadvantages

Material extrusion FDM/FFF/CFF Thermoplastics,composites,nanoparticle fillerpolymers

Stronger build parts compared to SLA, DLP, and MJM

Poor surface finish and slower build time compared; require support structure; post processing

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3D printing processes

Material extrusion• Material is selectively dispensed through a

nozzle– Fused filament fabrication (FFF)

• Thermoplastic material through heated extruder • Also called fused deposition modeling (FDM®)

Vat photopolymerization• Produce parts from photopolymer material in a

liquid state cured using either:– Stereolithography (SLA)

• Selectively cure material using lasers– Digital light processing (DLP)

• Cure photopolymer material using digital light projectors

Source: http://www.lboro.ac.uk/research/amrg/about/the7categoriesofadditivemanufacturin

g/materialextrusion//

Source: Wallace et al., “Validating continuous digital light processing (cDLP) additive manufacturing accuracy and tissue engineering utility of a dye‐initiator package,” Biofabrication, 2014, 6, 015003

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Typical 3D printing process workflow

• CAD design (3D model)

• Generation of *.stl or other compatible file

• Slicing of 3D model geometry

• Printing

• Post-processing/finishing

Source: https://technorphosis.files.wordpress.com/2014/04/3d‐printing‐process.jpg

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Heatsinks

• Metal heat sinks are commonly used in LED systems to keep LED junction temperatures low for optimum performance

– Drawbacks:• Heavy• Expensive• Overdesigned thermal management

• Study objective: – To investigate if custom heat sinks of suitable

thermal properties can be printed using the fused filament fabrication (FFF) method

• LED junction temperature below 85°C

ies.org/ac21http://www.e-conolight.com/creer-lr6-

series-6-deep-recess-led-downlight-2700k-50w-equivalent.html

https://www.prolighting.com/bxspr-a-0-3-m-g-u-

s.html?utm_source=google_shopping&utm_source=google&utm_medium=cpc&adpos=

1o5&scid=scplpBXSPR-A-0-3-M-G-U-S&sc_intid=BXSPR-A-0-3-M-G-U-

S&gclid=EAIaIQobChMI5cHahYCQ2gIVSuDICh02YghnEAkYBSABEgJcRfD_BwE

https://hdsupplysolutions.com/shop/ProductDisplay?catalogId=10054&langId=-

1&partNumber=P701144&rr_cid=701144&storeId=10051

Printed heatsinks

• A significant portion of an LED lighting product cost is for heat sink

– DoE SSL roadmap, R & D plan Sep. 2017.

• 3D printed metal or composite heat sinks have the potential to

– Reduce weight and cost– Optimize thermal management– Produce visually appealing heatsinks

13%8%

18%

41% 45% 26%

7%4%

5%

14% 19%

20%

14% 15%

16%

11% 9%15%

0%

20%

40%

60%

80%

100%

Outdoor areafixture

Interiordownlight

Replacementlamp

Shar

e of

tot

al c

ost

LED package Mechanical/Thermal/Electrical Optics Driver Assembly Overhead

Stonecipher and Alvarez (Aug. 2014) LEDs magazine webinar,

DoE SSL roadmap: R & D plan Sep. 2017

Comparison of Cost Breakdown for Different Lighting Applications

Source: DOE SSL Roundtable and Workshop attendees and industrial partners Solid‐State

Lighting; R&D Plan; Sept. 2017

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Tailored thermal properties of PLA heatsinks

• In this study, we investigated how composite polylactic acid (PLA) filaments with thermally conductive fillers affect thermal conductivity of printed heat sinks to manage the junction temperature, Tj, of the LED.

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0%

20%

40%

60%

80%

100%

120%

0.0 0.5 1.0 1.5 2.0 2.5Re

lative

ther

mal

cond

uctiv

ityLayer height [mm]

y = 1.5541xR² = 0.9983

0

1

2

3

4

0 1 2 3 4

Cros

s-pl

ane Δ

T/ℓ

[°C/m

m]

In-plane ΔT/ℓ [°C/mm]

Fabrication of heat sink

Printing orientation and print layer height affect heat sink performance

Source: Olivia Privitera, Master’s project 2018

Print orientation Print layer height

Plotted with source data from Perera et al., Optical Engineering 2018

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Estimating Tj of LED with heat sink

Parameter ValueThermal power of LED package ( ) 1 ,2, 5, and 10 W

LED package thermal resistance ( ) 10°C/W

Diameter of LED package ( 12.7 mm

Heat sink length ( ) 10.0 cm

Heat sink width ( ) 10.0 cm

Heat sink thickness ( ) 2.5 mm

Heat sink surface emissivity ( ) 0.9

Ambient temperature ( 20°C

LED heat sink

LED package

Thermal conductivity of aluminum ~200 W m-1 K-1

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Estimated Tj with different material heat sinks

27.8 mm28.05 mm

34.11 mm

8°C

39°C

LED source energized at 2 W electrical power

2016

2018

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Estimated and measured LED Tj for different material heat sinks

Simulation result at 1 W thermal power

27.8 mm28.05 mm

34.11 mm

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Predicting LED Tj at different LED power

41.9°C

22.9°C

41.7 mm28.05 mm

34.11 mm

27.8 mm28.05 mm

34.11 mm

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Summary

• Materials tested had effective κ-values ranging from ~0.3 to ~10 W m-1 K-1

• The 3D-printable composite thermoplastic materials with κ-values ~10 W m-1 K-1 exhibited less than a 10°C increase compared to an extruded aluminum straight fin heat sink

– Still ~2-4 times lower in κ-value required for most SSL heat sink applications

– Metal 3D-printing material is available for comparable results to aluminum heat sinks

• Thermal conductivity of available materials adequate for low- to mid-power applications wit low heat densities

600 lm/10 W

1500 lm/16 W

3000 lm/20 W

1300 lm/18W 240 lm/2W

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

MR 16 A-lamp A-lamp 6-indownlight

testedstraight finheat sink

Hea

t si

nk e

lect

rica

l pow

er d

ensi

ty

[W/m

m²]

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Electrical Components

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Objective

• Electrical traces are commonly used to conduct current within the lighting system

• Study objective: – To investigate if electrical traces can

be printed with suitable electrical properties

30

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Electrical properties of printed conductive traces

• In this study we investigated electrical resistivity of the 3D-printed conductive traces with three types of materials and print orientations:

– Graphene infused PLA– Carbon nanotube based PLA– Conductive carbon black based PLA

• Results:– Graphene infused PLA showed the lowest resistivity

(6.1 x10-3 Ωm) of all three materials, but it is much higher than copper traces (1.7 x10-8 Ωm) commonly used in PCB applications.

– In-plane build orientation showed the lowest resistivity (70-80% lower compared to cross-plane)

Voltage channel

Current channel

3‐D printed trace

V

A

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Summary

• There are commercial inks with resistivity values similar to copper.

– But they cannot be processed using unmodified FFF-type 3D printers.

• Requires paste extruder attachments to benefit from these highly conductive materials

• For example, Yu et al., recently reported a method where 3D-printed hollow channels within elastomer structures were filled with injected liquid metal to form electrical traces.

https://support.voxel8.co/hc/en‐us/articles/208004096‐Working‐with‐the‐Conductive‐Silver‐Ink‐Solvent

Yong‐Ze Yu, Jin‐Rong Lu, Jing Liua; 3D printing for functional electronics by injection and package of liquid metals into channels of mechanical structures, Materials and Design 122 (2017).

Yong‐Ze Yu et al., 2017

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Optical Components

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Optics

• LED light fixtures require secondary optics– For beam shaping

• Typically, optical components are either reflective or transmissive type.

• Properties of the optical component affect fixture efficiency and beam quality.

• Study objectives– To understand how short-term and long-term

optical properties are affected when using 3D-printed optical components

– To understand light transmission and scattering properties as a function of print resolution and print orientation

– To understand reflected and transmitted light as a function of time

Olivia Privitera, Yi‐wei Liu, Indika U. Perera, Jean Paul Freyssinier, Nadarajah Narendran, "Optical properties of 3D printed reflective and transmissive components for use in LED lighting fixture applications," Proc. SPIE 10940, Light‐Emitting Devices, Materials, and Applications, 109401X (2 April 2019); doi: 10.1117/12.2510063 Event: SPIE OPTO, 2019, San Francisco, California, United States

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3D printed reflective optics

• Materials used:– Reflective polylactic acid (PLA) - 2 types– Copolyester with no styrene (CoP) – single

type

• Samples– For each of the three materials, nine samples

were printed in different thicknesses by varying the extrusion width or the number of extrusions.


Printing parameters of the reflective samples using fused filament fabrication (FFF).

The integrating sphere setup used to measure the total reflectance and spectral reflectance of the samples.

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Short-term performance results

• Reflectance properties of 3D printed samples.

– Reflectance increased as sample thickness increased

• Up to approximately 2-mm • Constant beyond 2 mm (80%, 90%, 92%)

– Spectral reflectance is different for different materials


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Long-term performance results

• Reflectance properties of 3D printed samples as a function of time exposed to an ambient temperature of 50°C

– Reflectance remained nearly constant over time

• No degradation observed during the test period


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3D Printed transmissive optics

• Objective– To understand light transmission and scattering

properties as a function of print resolution and print orientation

• Test samples– Print resolutions (50 μm and 250 μm)– Print orientation: in-plane and cross-plane

• Results:– Polishing improved performance– Both print resolution and print orientation affect

light transmission and scattering• Increased print resolution 250 μm to 50 μm and in-

plane print orientation, increased light transmission and decreased light scattering

Beforepolishing

After polishing

50 m

250 m

laser

In‐plane

laser

Cross‐planeNarendran, N., Perera, I.U., Mou, X., and Thotagamuwa, D.R., “Opportunities and challenges for 3‐D printing of solid‐state lighting systems,” Proceedings of SPIE 10378, 16th International Conference on Solid State Lighting and LED‐based Illumination Systems, SPIE Optics + Photonics, San Diego, Calif., August 2017, Paper 10378‐35 (2017).

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Printed transmissive optics: long-term performance

• Results– Transmissivity decreases by approximately 1.5% per mm in thickness– The SLA resin tested showed a systematic reduction in transmittance in the 400 nm to 500 nm

region when exposed to 50°C. • Can result in undesirable color shift.


Relative change in spectral transmittance (left); and average transmissivity (right) as a function of time when exposed to an ambient temperature of 50 deg. C.

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Novel Optics

• Objective: To develop a novel optic and investigate its potential for 3D printing

– Example: A rectangular transparent optic• Difficult to manufacture using traditional methods

like injection molding but can be easily made using 3D printing techniques

– Planar surfaces with internal refractive structures

• Output beam shape depends on the cavity size, spacing, shape, etc., and light source(s) location(s).

Thin planar optic

Light source

Planar optic with cavities

Beam distribution

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Tailored beam with planar optic with internal cavities (simulation)10 mm

R=15 mm

10 mm

R=15 mm

Parameter Spherical cavity

Hemi‐sphericalbumps

Total flux output [lm] 113 110

Efficiency 0.55 0.53

Max. intensity [cd] 29 1179

FWHM [deg.] 150 6

Wide beam Narrow beamLED source – 205 lumens

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0°

45°90°

0°

45°90°

Tailored beam with planar optic (simulation)

Different beam distributions can be created by changing the internal cavity geometry and size

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3D printed optic with 1 mm hemi-spherical dimples (Simulation)

Parameter Value

Total flux output [lm] 160

Efficiency 0.78

Max. intensity [cd] 69

10 mm

R=1 mm

0°

45°90°

LED source – 205 lumens

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3D printed optic with 1 mm hemi-spherical dimples

Simulated illuminance at 437 mm Measured illuminance at 457 mm

Optic designed by LRC and printed by

Henkel

Simulation versus measured results

ies.org/ac45Illuminance [lx]

3D printed planar optic to produce uniform illuminance on the task plane (Measured results)By selecting proper dimensions and shapes for the internal cavities the beam distributions can be tailoredExample: Uniform illuminance

>200

Measured Simulated±300 mm

square±402 mm

square±300 mm

square±402 mm

squareAvg. E [lx] 136 99 138 120Max. E [lx] 234 234 216 216Min E [lx] 60 0 68 38Max/Min 3.9 NA 3.2 5.6Flux [lm] 52 66 53 79Efficiency 35% 44% 35% 53%

Optic designed by LRC and printed by

Henkel

LED source – 150 lumens

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Summary - printed optics

• High performance (short and long term) reflective optics can be printed using presently available commercial materials.

– Print thickness and orientation affects reflectance properties

• Better materials are needed for making reliable transmissive optics

• Novel optics that cannot be easily made using traditional manufacturing methods can be 3D printed

– Greater benefits: Easy to clean, allows for easy integration in light fixtures.

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Final Remarks

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• 3D printing offers new possibilities today – Today, visually pleasing functional components for light fixtures can be printed

• Decorative lamp shades; Novel heat sinks suitable for low to mid watt LED lighting fixtures; Reflective optics with high reflectivity and longevity

• Novel transmissive optics for tailoring beam patterns

– However, cost is much higher today.

• Improvements needed– New components designed for 3D printing– New materials for 3D printing– New printer technologies to make and assemble– Speed of manufacturing– Manufacturing cost

Source: Olivia Privitera, IESNYC thesis prize presentation May 2018

3D printing is poised to change the lighting industry and reverse the commoditization

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Acknowledgments

• IES Conference Committee • LRC faculty, staff and students

Jean Paul Freyssinier, Yiwei Liu, Olivia Privitera, Valeria Terentyeva-Holland, Kasey Holland, Akila Udage, Sachintha de Vas Gunawardena, Dinusha Thotagamuwa, Martin Overington, Howard Ohlhous, Jennifer Taylor

• LRC internal funding• ASSIST (2016-2018)• FAA contract # 16-G-019 (2016-2017)

Future work at the LRC– Education– Industry consortium– Funded projects

ASSIST Sponsors2016-2018

Acuity Brands LightingAmerlux

BAE SystemsCurrent by GE

Crystal ISDow Corning

EatonFAA

FineliteHubbell Lighting

NYSERDAOSRAM Opto

SemiconductorsPhilips

Seoul SemiconductorUS EPA

These projects were supported by above mentioned organizations and that such support does not constitute an endorsement by these organizations of the views expressed therein.

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2019 Annual ConferenceAugust 8 -10 | Omni Louisville Hotel | Louisville, KY

Thank you

www.lrc.rpi.edu/programs/solidstate

3D Printing: Can it work for lighting? - lrc.rpi.edu · – Binder jetting (BJ) • Powder bed and...

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