Lecture 10

Question 1

What is the additive manufacturing process?

Answer 1

1. Generation of a single layer (contour, thickness)
2. Connecting of each layer with the previously generated one

REPEAT

Question 2

Which technique(s) builds parts through polymerisation?

Answer 2

• Stereolithography
• Photopolymer Jetting

Question 3

Which technique(s) builds parts through bonding agent?

Answer 3

• Binder jetting

Question 4

Which technique(s) builds parts through melting?

Answer 4

• Laser melting
• Electron Beam Melting
• Fused deposition modelling (FDM)
• Laser sintering
• Material Jetting

Question 5

What are the 3 additive manufacturing technologies/types?

Answer 5

• Polymerisation
• Using Bonding agent
• Melting

Question 6

What are the characteristics of parts built through polymerisation?

Answer 6

• Lower durability
• Smoother surface finish
• Higher detail
• Highly applicable for prototypes & indirect processes

Question 7

What are the characteristics of parts built through the use of a bonding agent?

Answer 7

• Medium durability (more than polymerised, less than melted)
• Meduim surface finish (rougher than polymerised, smoother than melting)
• Medium detail

Question 8

What are the characteristics of parts built through melting?

Answer 8

• High durability
• Rougher surface finish
• Lower detail
• Applicable for manufacture of functional parts

Question 9

How does laser melting of metals work?

Answer 9

• 2 platforms, one rising (sith the metal powder supply), and one lowering (the build platform)
• Powder for the new layer is pushed onto the build platform
• Laser “melts” the required shape into the powder. Build platform moves down and new layer of powder is pushed onto build platform

Question 10

What is the purpose of shielding gas flow?

Answer 10

The fumes from the melting of the metals is removed by circulation (becasuse they may interrupt the laser)

• Prevents oxidation and contamination
• Ensures high material quality and process stability

Question 11

What is LBPF?

Answer 11

Laser bed powder fusion

Question 12

What are the proccess parameters of LPPF?

Answer 12

• Scanning speed (basically how long the laser is pointed at a specific spot)
• Laser power
• Hatch spacing (the distance from one melted “pool” to the next)
• Layer thickness

Question 13

What are the 3 main errors (for deffect formation) in LPBF?

Answer 13

• Keyhole formation (vapour gets trapped in the melt pool before it solidifies). Creates keyhole pore
• Balling up (when teh laser doesn;t have enough energy or time to properly melt the powder and bond it).
• Poor bonding/lack of fusion

Question 14

What are the advantages of LPBF titanium?

Answer 14

• Print porous structures (optimal for cell migration & prolifieration)
• Bone grafting not necessary
• controlling porosity allowing for bone compatible elastic modulus design

Question 15

What is the effect of varying porosity in LPBF titanium?

Answer 15

Adapted stiffness/elastic modulus

Question 16

What is the PSI process?

Answer 16

1. Obtain patient data
2. Anatomical segmentation
3. Pre-surgical planning/design & Pre-processing for production
4. Additive manufacturing (production)
5. Post-processing
6. Quality control
7. Cleaning, sterilisation , & packaging
8. Implantation

Question 17

What are the purposes of support structures when printing?

Answer 17

Fixation (hlding it in place)

Heat dissipation (otherwise heat would stay in teh part, increasing continously)