Metal 3D Printing of Low-NOx Fuel Injectors with Integrated

Temperature SensorsTorres, J., 1,3 Mireles, J., 1,3 Chowdhury, A., 1,2 Wicker, R.,1,3 Choudhuri, A.,1,2

1 Department of Mechanical Engineering, The University of Texas at El Paso2 Center for Space Exploration and Technology Research, The University of Texas at El Paso

3 W.M. Keck Center for 3D Innovation, The University of Texas at El Paso

Process Characterization:

Objective:• To utilize additive manufacturing for the fabrication of

seamless low-NOx fuel injectors with integrated

temperature measurement capabilities.

Electron Beam Melting:

Results

Future WorkMethodology & Materials

Introduction

Powder removal methodologies:

Powder removal demonstration:

The authors acknowledge the financial support for this work by

the DOE - National Energy Technology Laboratory. Award

Number:DE-FE0026330.

Acknowledgements

Student Involvement

• Evaluate other powder removal methods including process

parameter variations.

• Begin the re-design and fabrication of a Low-NOx fuel injector

given design constraints.

Takeaways:

Process characterization:

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Task 1: Development of design methodologies for EBM

Fabrication of test parts for technology evaluation

Evaluation of test parts

Re-design for AM of Low-NOx fuel injector

Alternative designs for sensor integration

Task 2: Development of powder removal techniques

Powder removal for internal channels

Powder removal for internal cavities

Process parameter modifications for optimal powder sintering

Task 3: Testing of EBM-fabricated fuel injectors

Functionality assessment of EBM-fabricated fuel injector

Year 1 Year 2 Year 3

Letter Feature Factor Tested

A Square base

Dimensional accuracy

B Lateral ridges (+)

C Lateral ridges (-)

D Descending cylinders (-)

E Descending cylinders (+)

F Staircase (-)

G Staircase (+)

H Cylinders (-)

I Cylinders (+)

J Ramps Surface roughness

K Rectangular prisms Linear displacement error

L Tensile bar Ultimate tensile strength

EBM part fabrication:

Test parts fabricated

from different

machine models

a) A2X, b) A3, c) S12

a) b)

c)

Test parts fabricated for powder removal

demonstration, each containing different

sized output channels (1mm - 6mm)

Measurement setup

Process characterization:

• Features smaller than 2.5 mm become deformed and the

fabricated part measured larger than the intended geometry.

• Features larger than 2.5 mm are very close to the intended

geometry.

• Walls tend to be thicker than the intended geometry, which may

be due to surface roughness due to powder size.

Powder removal:

• Powder removal did not progress after 10 minutes of removing

powder using the machine’s powder removal station.

• Ultrasonic powder removal method is currently under further

evaluation.

13

13.5

14

14.5

15

15.5

16

16.5

17

17.5

18

1 mm hole 2 mm hole 4 mm hole 6 mm hole

Wei

ght

(gra

ms)

19mm Cylinder

Weight Initial Weight (+2 min) Weight (+2 min) Weight (+2 min) Weight (+2 min)

126

127

128

129

130

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132

133

134

135

1 mm hole 2mm hole 4 mm hole 6 mm hole

Wei

ght

(gra

ms)

35mm Cylinder

Weight Initial Weight (+2 min) Weight (+2 min) Weight (+2 min) Weight (+2 min) Weight (+2 min)

38

39

40

41

42

43

44

45

46

47

1 mm hole 2 mm hole 4 mm hole 6 mm hole

Wei

ght

(gra

ms)

25mm Cylinder

Weight Initial Weight (+2 min) Weight (+2 min) Weight (+2 min) Weight (+2 min) Weight (+2 min)

0

5

10

15

20

Arcam A2 Arcam A2x Arcam S12

Dim

ensi

on

al d

evia

tio

n (

mm

)

Dimensional Deviation vs. Machine Model

0

0.5

1

1.5

2

2.5

3

3.5

4

D1* D2 D3 D4 D5 D6 D7

Dia

met

er (

mm

)

Cylindrical Boss Diameter

Original Arcam A2 Arcam A2x Arcam S12

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

E1 E2 E3 E4 E5 E6 E7**

Dia

met

er (

mm

)

Cylinder Hole Diameter

Original Arcam A2 Arcam A2x Arcam S120

5

10

15

20

25

30

35

Arcam A2 Arcam A2x Arcam S12

Surf

ace

Ro

ugh

nes

s (R

a)

Surface Roughness (45° ramp)

0

5

10

15

20

25

30

Arcam A2 Arcam A2x Arcam S12

Surf

ace

Ro

ugh

nes

s (R

a)

Surface Roughness (10° ramp)

289

289.5

290

290.5

291

291.5

292

292.5

293

293.5

294

294.5

1 mm hole 2 mm hole 4 mm hole 6 mm hole

Wei

ght

(gra

ms)

45mm Cylinder

Weight Initial Weight (+2 min) Weight (+2 min) Weight (+2 min) Weight (+2 min)