de la guerre Filomeno Martina Scope To compare the cost of a part made by WAAM vs traditional machined from solid To assess the sensitivity of cost to changes in key cost drivers process parameters ID: 631487
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Slide1
L
’argent
est le nerf de la guerre
Filomeno
MartinaSlide2
Scope
To compare the cost of a part made by WAAM vs traditional machined from solidTo assess the
sensitivity of cost to changes in key cost drivers / process parameters:Deposition rateBuy to fly ratioMaterial costMachine costCapacity
utilisation
Material removal rateSlide3
Machining from solid
Cost model terms:Mass of initial forging or billet cost of initial forgingBuy to fly ratio
material to be removedMaterial removal rate machining timeSlide4
WAAMCost
model terms:Mass of substrate cost
of substrateBuy to fly ratio material to be deposited, and to be removedDeposition rate + Starts&Stops
deposition time
Material removal rate
machining timeSlide5
Assumptions
General:No tooling / setup consideredNo post processing, non-destr
. testing, on-line monit.1 operator for 1 machineMachining:One type of operationIf WAAM machine cost > £250k
Hourly rate
mach
= hourly rate WAAM
WAAM:
Starts&Stops
: 1.1
; if If WAAM machine cost > £250k
SS = 1.5 to include rollingPlate £/kg = Billet £/kgOnly 1 type of machining operationSlide6
Specific costs / performances
Unless specified differently:Cost of machine: £180kDepreciation: 5 yearsUtilisation: 80%
Labour cost: £45/h WAAM hourly rate = £82/hCost of wire: £130/kgCost of forging: £60/kgDeposition rate: 1 kg/h
Material removal rate: 8 kg/h (accounts for complexity)
Machining hourly rate: £60/h
Cost of inspection: £1000
To transfer to other materials, change:
Deposition rate, cost of raw materials, material removal rateSlide7
ResultsSlide8
Part costf(BTF, mass)Slide9
Part costf(BTF, mass)Slide10
Part costf(BTF, mass)Slide11
Part costf(BTF, mass)Slide12
Part costf(BTF, mass)Slide13
Specific cost of depositionf(deposition rate, BTF)Slide14
Specific cost of depositionf(deposition rate, machine cost)
Depreciation: 5 years
BTF: 1.5Slide15
Specific cost of depositionf(deposition rate, utilisation)
Depreciation: 5 years
BTF: 1.5Slide16
30 kg part costf(material removal rate, BTF)Slide17
Specific cost of depositionf(wire cost, BTF)Slide18
Specific cost of depositionf(wire cost, machine cost)
BTF: 1.5Slide19
Specific cost of deposition(WAAM vs
high DR wire process)
WAAM:HR:
£82/
h
DR:
1
kg/
h
Process 1:HR: £360/hDR: 7 kg/h
Process 2:HR: £170/hDR: 7 kg/hTypical BTF of High dep. Rate is 10Slide20
Specific cost of deposition(WAAM vs
high DR wire process)
WAAM:HR: £82/hDR: 1 kg/h
Process 1:
HR: £360/h
DR: 7 kg/h
Process 2:
HR: £170/h
DR: 7 kg/h
Typical BTF of High dep. Rate is 10Slide21
Specific cost of deposition(WAAM vs
high DR wire process)
WAAM:HR: £82/hDR: 1 kg/h
Process 1:
HR: £360/h
DR: 7 kg/h
Process 2:
HR: £170/h
DR: 7 kg/h
Typical BTF of High dep. Rate is
10This makes them break even for very high BTF (machined from solid)Slide22
Specific cost of deposition(WAAM vs
high DR wire process)
WAAM:HR: £82/hDR: 1 kg/h
Process 1:
HR: £360/h
DR: 7 kg/h
Process 2:
HR: £170/h
DR: 7 kg/h
Typical BTF of High dep. Rate is 10
This makes them break even for very high BTF (machined from solid)WAAM’s BTF is <2Slide23
Specific cost of deposition(WAAM vs
high DR wire process)
WAAM:HR: £82/hDR: 1 kg/h
Process 1:
HR: £360/h
DR: 7 kg/h
Process 2:
HR: £170/h
DR: 7 kg/h
Typical BTF of High dep. Rate is 10
This makes them break even for very high BTF (machined from solid)WAAM’s BTF is <2Lots of room to be cheaper than machiningSlide24
The problem of powder-bed processes
Machine cost: £500k
DR: 0.1 kg/h100% powder utilisation50% beam-on timeNo post-proc.Slide25
CASE STUDIESSlide26
Case studies
BAE Systems spar
Design option
Mass
(kg)
BTF
Cost (£k)
Cost
red.
Original
, machined
17
6.5
7.2
-
Original,
WAAM
17
2.2
5.1
29%Slide27
Case studies
Bombardier rib
Design option
Mass
(kg)
BTF
Cost (£k)
Cost
red.
Original
, machined
20
12
16.2
-
Original,
WAAM
20
2.3
5
69%Slide28
Case studies
Bombardier rib (steel)
Design option
Mass
(kg)
BTF
Cost (£k)
Cost
red.
Original
, machined
36
12
1.6
-
Original,
WAAM
36
2.3
0.7
55%Slide29
Case studies
A pylon mount
Design option
Mass
(kg)
BTF
Cost (£k)
Cost
red.
Original
, machined
7.6
5.1
2.5
-
Original,
WAAM
7.6
1.5
2.4
4%
Topologically
optimised, machined
3.9
6
1.5
39%
Topologically
optimised,
WAAM
3.9
1.5
1.1
55%Slide30
Case studies
15 kg aluminium wing rib (DR = 1kg/h)
Design option (
MRR = 65 kg/h)
BTF
Cost (£k)
Cost
red.
Machined from
solid
45
4.9
-
WAAM option
1
2.9
1.7
65%
WAAM option
2
12.3
2
58%
Design option (
MRR = 323 kg/h)
BTF
Cost (£k)
Cost
red.
Machined from
solid
45
4.4
-
WAAM option
1
2.9
1.7
61%
WAAM option
2
12.3
1.9
56%
Option 1:
Option 2:
CAD:Slide31
Case studies
Titanium wing frame
Design option (MRR = 65 kg/h)
BTF
Cost (£k)
Cost
red.
Machined from
solid
69
4.9
-
WAAM option
1 (thin substrate)
7
2.6
67%
WAAM option
2 (thick substrate)
8
2.4
69%Slide32
Example part 1
WAAM
HiDR
process
Saving by using WAAM
Deposition
BTF
3
10
-
Substrate
BTF
12
12
-
Overall BTF ratio
8
11
-
Cost of part machined from solid
£ 12155 (BTF =
60)
-
Cost of AM
part
£ 3189
£ 4389
27%
Finished product
mass
3 kg
3 kg
-
Deposited mass
4 kg
13 kg
69%
Cost reduction
74%
64%
-
Non-recurring cost of tooling and programming: £1500Slide33
Example part 2
WAAM
HiDR
process
Saving by using WAAM
Deposition
BTF
2
10
-
Substrate
BTF
3
3
-
Overall BTF ratio
3
5
-
Cost of part machined from solid
£ 16184 (BTF =
30)
-
Cost of AM
part
£ 3258
£ 6179
48%
Finished product
mass
8 kg
8
kg
-
Deposited mass
5 kg
32 kg
84%
Cost reduction
80%
62%
-
Non-recurring cost of tooling and programming: £1500Slide34
Conclusions
A cost model to compare WAAM vs Machining was definedSensitivity analyses were carried out and it was demonstrated that:
Increasing the deposition rate above 1 kg/h has no economic benefit (for a robot-based cell)Higher capital cost higher hourly rates; increasing deposition rate reduce specific costThe material removal rate does not really matterGiven the current conditions, WAAM always cheaper than machining
Increasing deposition rate is useless if also BTF increases
Powder-bed processes must build their cases on freedom of design, until cheaper and faster machines become available
Thanks for your attention! Questions?