Temperature Simulations and Measurements p for Process - - PowerPoint PPT Presentation

▶
temperature simulations and measurements p for process
SMART_READER_LITE
LIVE PREVIEW

Temperature Simulations and Measurements p for Process - - PowerPoint PPT Presentation

Aug 14, 2022 25 likes •386 views

Advanced Qualification of Additive Manufacturing Materials Workshop Manufacturing Materials Workshop Temperature Simulations and Measurements p for Process Qualification in Powder-Bed Electron Beam Additive Manufacturing Electron Beam

slide-1
SLIDE 1

Advanced Qualification of Additive Manufacturing Materials Workshop

Temperature Simulations and Measurements

Manufacturing Materials Workshop

p for Process Qualification in Powder-Bed Electron Beam Additive Manufacturing Electron Beam Additive Manufacturing

Kevin Chou Kevin Chou

Professor Mechanical Engineering Department The University of Alabama The University of Alabama Assistant Director for Technology Advanced Manufacturing National Program Office g g U.S. Department of Commerce

July 20, 2015

slide-2
SLIDE 2

Disclaimer and Note

  • The materials presented and opinions expressed in this seminar were solely from

the presenter himself. They do not represent the viewpoints of The University of Alabama, nor the Advanced Manufacturing National Program Office.

  • The materials presented in this seminar are mainly from the following articles.

– Cheng, B., S. Price, J. Lydon, K. Cooper and K. Chou, "On Process Temperature in Powder‐Bed El t B Additi M f t i M d l D l t d E i t l V lid ti ” J l Electron Beam Additive Manufacturing: Model Development and Experimental Validation,” Journal

  • f Manufacturing Science and Engineering, Vol. 136, No. 6, pp. 061018 (1‐12), 2014.

– Price, S., B. Cheng, J. Lydon, K. Cooper and K. Chou, "On Process Temperature in Powder‐Bed Electron Beam Additive Manufacturing: Process Parameter Effects,” Journal of Manufacturing Science and Engineering, Vol. 136, No. 6, pp. 061019 (1‐10), 2014. Science and Engineering, Vol. 136, No. 6, pp. 061019 (1 10), 2014. – Gong, X., J. Lydon, K. Cooper, and K. Chou, “Beam Speed Effects on Ti‐6Al‐4V Microstructures in Electron Beam Additive Manufacturing,” Journal of Materials Research, Vol. 29, No. 17, pp. 1951‐ 1959, 2014. – Gong, X., J. Lydon, K. Cooper, and K. Chou, “Characterization of Ti‐6Al‐4V Powder in Electron‐Beam‐ g, , y , p , , Melting Additive Manufacturing,” International Journal of Powder Metallurgy, Vol. 51, No. 1, pp. 1‐ 10, 2015.

Contact information: Kevin Chou, kchou@eng.ua.edu, 205‐348‐0044

2

slide-3
SLIDE 3

Quality Control in AM Material and Process Material and Process

Process

∆2

Part

∆2 ∆ ∆f

EBAM Process Video

∆1

Feedstock

EBAM Process Video

GE Aviation

3

∆f = Fn (∆1, ∆2, etc.)

slide-4
SLIDE 4

EBAM System Characteristics EBAM System Characteristics

EBAM machine ( l ld d l) (example, old model) Build chamber High power 60 keV electron gun Leaded glass High strength glass

4

No moving part Heat shield Sensor access limitation

slide-5
SLIDE 5

EBAM Viewport Window EBAM Viewport Window

Metal Shutter Leaded Glass Build Build Area

Machine Outside

Sacrificial Glass Vacuum Glass Heat Shield

Machine Inside

5

Metalized film deposit

slide-6
SLIDE 6

EBAM Process Characteristics

Speed Function (SF)

800 900 1000 14 16 18 300 400 500 600 700

Beam Speed (mm/s)

6 8 10 12 14

Beam Current (mA)

B S d f ti (SF h i ht)

100 200 5 10 15 20 25 30

B Build Height (mm)

2 4 5 10 15 20 25 30

B Build Height (mm)

Vacuum (little He) Pre-heating, sintering W ( 650 ˚C)

Beam Speed = function (SF, height)

y = 24.133x - 12.631 R² = 0.9996 y = 20.211x - 12.612 R² = 0.9996 y = 17.866x - 25.355 1400 1600 1800 Layer 95 (6.65 mm) Layer 97 (6.79 mm)

Warm process (> ~650 ˚C) High scanning speed Process parameters change through the build

y R² = 0.9988 y = 10.587x - 0.4949 R² = 0.9997 600 800 1000 1200 Beam Speed (mm/s) Layer 153 (10.71 mm) Layer 155 (10.85 mm) Layer 223 (15.61 mm) Layer 225 (15 75 mm)

6

g Metalizing film Slow post-process cooling

200 400 10 20 30 40 50 60 70 Speed Function Index (15.75 mm) Layer 347 (24.29 mm) Layer 349 (24.43 mm)

slide-7
SLIDE 7

EBAM Process/Material Studies EBAM Process/Material Studies

Process Physics Process Physics

Temperature AM Part (4) Powder-Bed (1) Temperature Simulation (2) Powder-Bed (1) Ti-6Al-4V Temperature Measurement (3)

7

slide-8
SLIDE 8

(1) Feedstock Characterization

(1) Feedstock Characterization

√

 Powder-Bed Particles, Porosity

  • Metallography, Micro-CT

√

 Thermal Conductivity

Hot Disk Thermal Analyzer

√

  • Hot-Disk Thermal Analyzer

8

slide-9
SLIDE 9

Preheated Powder

Z-plane X-plane

9

slide-10
SLIDE 10

Porosity Study - Micro-CT y y

  • 10 mm Ti-6Al-4V Cube (hollow)
  • Skyscan 1172 Micro CT
  • Skyscan 1172 Micro-CT
  • Size/Porosity Distribution

~ 2 μm resolution ~ 2 μm resolution

Loose powders

10

Sintered powders

slide-11
SLIDE 11

Porosity and Powder Size y

  • Powder-Bed Porosity, ~ 50%
  • Particle Size Distribution
  • Particle Size Distribution

Major: ~ 30 to 50 μm

(b)

(a)

11

slide-12
SLIDE 12

Powder Thermal Conductivity

  • TPS2500 S Thermal Analyzer (Hot Disk)
  • Solid and Hollow samples

12

Solid vs. Hollow Hollow sample with shell removed (1 side)

slide-13
SLIDE 13

Powder Thermal Conductivity

  • Sintered Powder Specimens

13

slide-14
SLIDE 14

(2) Temperature Simulation

  • Finite Element Modeling

 Heat Transfer  Heat Source

√ √

 Heat Source  Material/Powder Properties

√ √ √

 Latent Heat of Fusion

√

14

slide-15
SLIDE 15

Governing Equations

Heat Transfer T c T c  

) ( ) (  

g q

T - Temperature

x T c v t T c Q T k

p s p

          

) ( ) ( ) (  

  • Absorbed heat flux

c - Specific heat capacity ρ - Density λ - Thermal conductivity C d f h

 

, , x y z

Q

Latent Heat of Fusion

 

d f

Assumptions:

vs - Constant speed of the moving heat source

 

f

H T cdT L f   

S

T T     

f 

,

S S L

T T T T T    p

  • Heat Conduction
  • Negligible molten flow within molten pool
  • Radiation considered as boundary condition
  • 1

L S

T T     

f 

,

S L L

T T T T T   

ΔHf - latent heat of fusion

  • Uniform temperature as the part initial temperature

15

Tl - liquidus temperature Ts - solidus temperature fs - solid fraction

slide-16
SLIDE 16

Heat Source Equations

Intensity distribution: a conical source:

  • Horizontal – Gaussian distribution
  • Vertical – Decaying with increasing of

penetration depth

η - electron beam efficiency coefficient U - voltage U voltage Ib - current S - penetration depth ΦE- beam diameter ΦE beam diameter xS, yS - horizontal position of heat source center Hs - Gaussian heat source, Cline and Anthony Iz - penetration function, Zäh and Lutzmann

z

p ,

16

slide-17
SLIDE 17

Simulation Example p

Process Simulation Animation

slide-18
SLIDE 18

(3) Temperature Measurements

  • Near IR Thermography

 Spectral Range  B ild A

Vi A

√ √

 Build Area View Access  Resolutions (Spatial/Temporal)

√ √

 Emissivity  Transmission Loss

√ √

 Transmission Loss

√

18

slide-19
SLIDE 19

EBAM Temperature Measurements Measurements

Near Infrared Thermal Imager

  • LumaSense MCS640
  • Spectral Range: 780 – 1080 nm

Spectral Range: 780 – 1080 nm

  • 640 by 480 FPA (Amorphous Si

based)

  • Temperature Range: 600 to 3000 ˚C

Temperature Range: 600 to 3000 C (3 domains)

  • Frame Rate: Max. 60 Hz
  • Lens: ~ 500 mm Focal Distance

Lens: 500 mm Focal Distance

  • View Area: 32 mm by 24 mm
  • Spatial Resolution: ~ 50 µm

19

Challenges: Emissivity and Transmission

slide-20
SLIDE 20

Measurement Setup

Emissivity (Single Setting, Estimated) Emissivity (Single Setting, Estimated) Transmission (Calibrated, 3 Ranges, with Glasses)

20

Heat shield

slide-21
SLIDE 21

NIR Video Examples p

Build model:

  • 25. 4 mm square block

NIR Video 1 High Temperature Range Medium Temperature Range NIR Video 2

21

slide-22
SLIDE 22

Temperature Profile Analysis (Hatch Melt) (Hatch Melt)

Single Frame (Raw Data) Average (One Video)

slide-23
SLIDE 23

Transmission Loss Study

Controlled

Lighter side Darker side

Viewing Area

Controlled Exposure

Sacrificial glass with two levels of metallization. Thermal image on lighter side Thermal image on darker side

slide-24
SLIDE 24

Controlled Exposure Experiment p p

Temperature Profiles Observed Through Different Levels of Metallization

y = 1 1602x 171 85 2250 2500 2200 2400 2600 y = 1.1602x - 171.85 R² = 0.9822 1750 2000 de Temperature (C) 1600 1800 2000 2200 mperature (C) Light Side D k Sid 1250 1500 Lighter Sid 1000 1200 1400 Tem Dark Side 1000 1000 1250 1500 1750 2000 2250 2500 Darker Side Temperature (C) 800

  • 8
  • 6
  • 4
  • 2

2 Distance (mm)

Average Temperature Profiles Relationship Between

24

g p (6.37 mm Build Height) p Temperatures Observed Through Different Levels of Metallization

slide-25
SLIDE 25

Molten State Emissivity Estimate y

  • 1. Identify Measured Liquidus
  • 1. Identify Measured Liquidus

Temperature

  • 2. Solve for Apparent Liquidus

Temperature, (function of d li id t t measured liquidus temperature, assumed emissivity, etc.)

  • 3. Solve for True Emissivity,

(function of True Liquidus ( q Temperature, Apparent Liquidus Temperature, etc.)

Estimated molten pool ε: ~0.28

Estimate Tm d Estimate Tapp (ε=1), with Tm Estimate εtrue with true Tm, εtrue value

25

measured with Tm measured

m

Tapp

slide-26
SLIDE 26

Temperature Profile Compensation p p

3000 Uncompensated 2200 2600

e (°C)

Compensated for Transmission Loss Compensated for Transmission Loss and 1400 1800

emperature

Emissivity Adjustment 600 1000

Te

Average Temperature Profile (6 37 mm Build Height)

600

  • 7
  • 6
  • 5
  • 4
  • 3
  • 2
  • 1

1 2

Distance (mm)

26

Average Temperature Profile (6.37 mm Build Height)

slide-27
SLIDE 27

Simulation vs. Experiment

Simulation

Set 1

Build height = 26.53 mm

Set 2

Build height = 16.87 mm

2200 2600 3000

°C)

Experiment Simulation

Beam Speed = 728 mm/s Beam Current = 7.2 mA Beam Diameter = 0.55 mm

Experiment

Set 2

Build height 16.87 mm

1400 1800 2200

Temperature (°

600 1000

  • 7
  • 6
  • 5
  • 4
  • 3
  • 2
  • 1

1 2

T Distance (mm) 27

slide-28
SLIDE 28

Process Parameter Effect

  • Speed Function (SF) Index

Process Parameter Effect

1000

p ( )

  • System Setting
  • Beam Speed, Current

500 600 700 800 900

peed (mm/s)

p ,

  • Tested Range
  • SF20 – SF65

100 200 300 400

Beam Sp

5 10 15 20 25 30

Build Height (mm)

14 16 18

A)

4 6 8 10 12

Beam Current (mA

28

2 4 5 10 15 20 25 30

B Build Height (mm)

slide-29
SLIDE 29

NIR Images – Different SF Indices

SF 20 SF 36 SF 50 SF 65

29

slide-30
SLIDE 30

Melt Pool Size Comparisons

7.7 mA current, 0.65 mm diameter, 6.65 mm build height

slide-31
SLIDE 31

Temperature Analysis Beam Speed Effect Beam Speed Effect

7.7 mA current, 0.65 mm diameter, 6.65 mm build height

slide-32
SLIDE 32

(4) Part Characteri ation (4) Part Characterization

 Microstructures (Phases, Grain Sizes)  M

h i l P ti (E H YS UTS)

√ √

 Mechanical Properties (E, H, YS, UTS)

√

32

slide-33
SLIDE 33

EBAM Ti-6Al-4V Microstructure

Side surface (X-plane) Scanning surface (Z-plane)

33

slide-34
SLIDE 34

Process Parameter Effects

300 140 220 260 100 120 140

e, µm dth, µm

Columnar β Equiaxed β 100 140 180 40 60 80

quiaxed β size lumnar β wid

20 60 15 25 35 45 55 65 20 40

Eq Co

15 25 35 45 55 65

Speed Function

34

slide-35
SLIDE 35

Mechanical Property (Nanoindentation)

Z l X plane

120 130 120 130

Z-plane X-plane

100 110

E, GPa

100 110

E, GPa

Young’s modulus

80 90 20 36 50 65

Speed Function

80 90 20 36 50 65

Speed Function

6.0 6.5 7.0 6.0 6.5 7.0

H d

4.0 4.5 5.0 5.5

H, GPa

4.0 4.5 5.0 5.5

H, GPa

Hardness

35

3.0 3.5 20 36 50 65

Speed Function

3.0 3.5 20 36 50 65

Speed Function

slide-36
SLIDE 36

Split-Hopkinson Bar Testing (P Allison) (P. Allison)

  • Uniaxial Tensile, Quasi-static and Dynamic
  • Mechanical Behavior

Mechanical Behavior

YS: ~975 MPa, UTS: ~1030 MPa Testing Video

36 36

1 mm