Lecture 6 part 2

Question 1

Why are aerospace applications suited to AM processes

Answer 1

Geometric complexity
•
Often small volumes
•
Weight reduction
•
Mechanical properties

Question 2

Fashion application advantages(2) and disadvantages(1)?

Answer 2

Great complexity available
Lack of assembly required

But who really gives a shit
(most established fashion designers dont care about the tech)

Question 3

AM offers efficient personalisation to a very high degree.
What does this mean for, say, a surgical guide.

Answer 3

Consolidated part, no screwing involved
Increases comfort for patient
Minimises surgery time

Question 4

How does High Speed Sintering aim to increase economical volumes for AM technologies (2)

Answer 4

Decrease cost
Increase speed

Question 5

What is the basic process by which HSS works?

Answer 5

Product cross section ink jet printed with a
Radiation Absorbing Material, then sintered
using an infrared lamp

Question 6

Describe the full HSS process:

Fill ______ supply area with loose ______
•
Preheat powder and feed area
•
Import .stl file &
slice to bitmaps
•
_______ _____ of powder from powder supply area
•
Print ___ onto cross-section (inkjet print-head)
•
Immediately ______ with infra-red lamp
•
_____ powder bed piston by ___ layer
•
Raise powder delivery piston & deposit next ______ _____
•
____-____ & remove part from powder ‘cake’
•
____-_______

Answer 6

Fill powder supply area with loose powder

•
Pre-heat powder and feed area
•
Import .stl file &
slice to bitmaps
•
Deposit layer of powder from powder supply area
•
Print RAM onto cross-section (inkjet print-head)
•
Immediately follow with infra-red lamp
•
Lower powder bed piston by one layer
•
Raise powder delivery piston & deposit next powder layer
•
Cool-down & remove part from powder ‘cake’
•
Post-process

Question 7

Look up these processes

Answer 7

Voxeljet
•
Sintermask
•
Selective Inhibition Sintering
•
Blueprinter

Question 8

Briefly Compare LS with HSS (currently)

Answer 8

The essential difference:

LS
input high energy for very short time
•
HSS
input lower energy, over a longer time

At the moment, they actually are about the same speed. Hss however offers the possibility of processing more ‘difficult’ materials

Question 9

What are the advantages of HSS?

Many of the same advantages as __, but:
•
_____ ____ is independent of cross section
•
Build time independent of _____ ___ _____ (faster & cheaper)
•
Less prone to _______
•
Print head __________ substantially better than laser limiting factor will be ______ ____
•
_______ machine system (no laser & optics system)
•
Easily ________ (e.g. extra print heads)
•
Better ability to _______ material
•
Does not use ________
•
Possibility of full ______?

Answer 9

Many of the same advantages as LS
•
Layer time is independent of cross section
•
Build time independent of parts per layer (faster & cheaper)
•
Less prone to warpage
•
Print head resolution substantially better than laser limiting factor will be powder size
•
Cheaper machine system (no laser & optics system)
•
Easily scalable (e.g. extra print heads)
•
Better ability to recycle material
•
Does not use nitrogen
•
Possibility of full colour?

Question 10

Limitations of HSS? (6)

(1 concerns market
2 concerns material
3 concerns ink
4 concerns powder
5 concerns part
6 concerns colour)

Answer 10

Still being commercialised

Processing certain materials is difficult

Differentiation between ink
and powder, is difficult

‘Hardness’ of un-sintered powder

Components of ink left in parts (i.e. not just Nylon-12)

Colour (currently, white powder + black ink = grey parts)