1 2016年7月1日

Factors Affecting the Adoption of 3D Printing 

Technologies (SLS) as Manufacturing Platforms – Role 

of Standards for Adoption

Praveen Tummala

2016-06-10

WWW.3DSYSTEMS.COM NYSE:DDD
SLS Print Technology

SLS:

• Uses thermoplastic semi-crystalline polymers as 

print materials

• Print material in powder form

• Powder material is pre-heated to 10 degrees 

below the melt point for every layer and a Laser is 

used to provide additional energy for melting

• Process is repeated layer after layer until the print 

is complete

• Capable of producing robust, durable & functional 

parts
Factors Affecting Adoption for Additive Manufacturing

1. Print Speed

2. Part Cost

3. Part Performance, Quality & Accuracy

4. Thermal Process Limitations - Thermal Distribution, Rate 

of Heating, Rate of Cooling

5. Intelligent Machine Controls – Closed-loop Feedback 

Controls, In-process Calibration, Smart Software, 

Measure & Record Process

6. Challenges Imposed by Material Form Requirements

7. Orientation of Parts & Orientation of Fillers in Composites

8. Quality & Reliability Standards; EH&S Standards

9. Lack of Studies concerning Part Performance over Time

10.Applications Development – White Papers, Process 

Guides
Print Speed

0.1 mm Layers 0.125 mm Layers

Total Build Height (mm) 300 300

Weight of Parts (Kg) 2.0 1.9

Total Build Time 23:28 18:34

Warm Up Time 1:19 58:23

Build Time 20:04 15:35

Cool Down Time 2:04 2:04

Scan Time 6:58 4:50

Add Powder Layer Time 12:38 10:11

Wait for Tempreature Time 1:43 1:26

Minimum Layer Compensation Time 0:13 0:11

Pause & Misc. Times (Mostly during cooldown) 1:54 1:50

Layer Thickness (mm) 0.100 0.125

Fill Laser Power, output value (W) 63 - 66 93 - 97

Outline Laser Power, output value (W) 20 30

Scan Spacing (mm) 0.20 0.25

Tensile Strength (MPa) 46.0 38.0

Elongation At Break (%) 22.0 15.0

Tensile Modulus (MPa) 1775 1460

Density (g/cc) 0.948 0.910
Part Cost; Part Performance, Quality & Accuracy

Part Cost:

• Cost of Print Material

• Recyclability of Print 

Material

Part Performance:

• Physical, Mechanical & 

Thermal properties

Part Quality:

• Sidewalls, Top & Bottom 

Surfaces, Warpage

Part Accuracy:

• Definition, Smallest 

Feature
Thermal Process Limitations – Rate of Cooling

Temp Set Point: 185C

PA12 

Material

Top of 

Build

Bottom 

of Build

Tensile 

Modulus, 

MPa

1850 2020

Tensile 

Strength, 

MPa

48 50

Elongation 

to Break, 

%

15 11
Intelligent Machine Controls

• Closed-loop Feedback 

Controls: Exists for most heaters 

but absent for Laser, Variation of 

beam shape and size center to 

the corners, Laser power variation 

in Z 

• In-process Calibration: Exists 

for primary Temp sensor only

• Smart Software: Capable of 

suggesting orientation, process 

parameters, allow ease of design 

etc.

• Measure & Record Process: For 

validation, problem determination 

& solving
Print Material Challenges

•Semi-crystalline thermoplastic in powder form (precipitated, 

cryo-ground)

•Particle size distribution (powder flow, part resolution)

•Thermal characteristics (process latitude) - melt & recrystallization (part distortion, part definition, heated powder 

cake hardness, powder recyclability)

•Powder flow characteristics (particle size, particle shape, static 

charges, change with temperature)

•Melt Viscosity & Surface energy (for coalescence and layer to 

layer adhesion)

•Powder recyclability (thermal characteristics, molecular weight 

change, agglomeration of heated powder)

•Excellent Thermal stability
Orientation of Parts & Orientation of Fillers

X vs Z; or at another angle to XY

Unfilled Material X 

Direction

Z 

Direction

Tensile Modulus, 

MPa

1760 1600

Tensile Strength, 

MPa

46.0 45.5

Elongation at

Break, %

19.0 9.5

Fiber Filled 

Material

X 

Direction

Y 

Direction

Z 

Direction

Tensile 

Modulus, MPa 5640 3390 2940

Tensile 

Strength, MPa 49.8 43.3 32.6

Elongation at 

Break, %

4.5 3.5 2.7

Fiber Orientation in X, Y, Z
Quality & Reliability Standards; EH&S Standards

Quality & Reliability Standards: 

Compliance to ISO, TS16949 type of standards for Machine 

& Materials manufacturing

Machine performance over time – Preventive maintenance

SPC techniques for reliability – six lot data, six sigma 

process

EH&S Standards:

Air Quality/Environmental testing - VOC emissions 

(hazardous decomposition products)

Explosion Severity testing
Part Performance over Time; Applications Development

Part Performance over Time: 

• Need to generate fatigue, creep, exposure, RTI type data

Applications Development:

• Advance through developing new applications for the AM 

processes, publish more white papers

• Generate better machine guides, material guides, process 

guides & troubleshooting guides
Adopt the Advantages

• Hollow Parts using Fused Deposition print process for Speed

• Lower Density but Higher Strength to weight ratio

Printed Part Density, g/cc 0.44

Tensile Strength, MPa 33

Strength-to-weight ratio, 

MPa/(g/cc) 76

Tensile Modulus, MPa 1710

Elongation at Break, % 22

• Freedom of part placement, orientation

• Capability to apply different parameters to different parts

• Change settings on the fly

• Different hatch patters for different speeds & properties
Acknowledgements

• Khalil Moussa

• Jenny Reilly

• Christian Folgar

• Steven Goransson
Thank you!!

May need to think outside the box to overcome these barriers