cost-model

1、L’argent est le nerf de la guerre,Filomeno Martina,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

2、:Deposition rateBuy to fly ratioMaterial costMachine costCapacity utilisationMaterial removal rate,Machining from solid,Cost model terms:Mass of initial forging or billet ? cost of initial forgingBuy to fly ratio

3、 ? material to be removedMaterial removal rate ? machining time,WAAM,Cost model terms:Mass of substrate ? cost of substrateBuy to fly ratio ? material to be deposited, and to be removedDeposition rate + Starts&St

4、ops ? deposition timeMaterial removal rate ? machining time,Assumptions,General:No tooling / setup consideredNo post processing, non-destr. testing, on-line monit.1 operator for 1 machineMachining:One type of opera

5、tionIf WAAM machine cost > £250k ? Hourly rate mach = hourly rate WAAMWAAM:Starts&Stops: 1.1; if If WAAM machine cost > £250k ? SS = 1.5 to include rollingPlate £/kg = Billet £/kgOnly 1

6、 type of machining operation,Specific costs / performances,Unless specified differently:Cost of machine: £180kDepreciation: 5 yearsUtilisation: 80% Labour cost: £45/h ? WAAM hourly rate = £82/hCost of

7、 wire: £130/kgCost of forging: £60/kgDeposition rate: 1 kg/hMaterial removal rate: 8 kg/h (accounts for complexity)Machining hourly rate: £60/hCost of inspection: £1000To transfer to other mate

8、rials, change:Deposition rate, cost of raw materials, material removal rate,Results,Part costf(BTF, mass),Part costf(BTF, mass),Part costf(BTF, mass),Part costf(BTF, mass),Part costf(BTF, mass),Specific cost of dep

9、ositionf(deposition rate, BTF),Specific cost of depositionf(deposition rate, machine cost),Depreciation: 5 yearsBTF: 1.5,Specific cost of depositionf(deposition rate, utilisation),Depreciation: 5 yearsBTF: 1.5,30 kg

10、 part costf(material removal rate, BTF),Specific cost of depositionf(wire cost, BTF),Specific cost of depositionf(wire cost, machine cost),BTF: 1.5,Specific cost of deposition(WAAM vs high DR wire process),WAAM:HR:

11、£82/hDR: 1 kg/hProcess 1:HR: £360/hDR: 7 kg/hProcess 2:HR: £170/hDR: 7 kg/hTypical BTF of High dep. Rate is 10,Specific cost of deposition(WAAM vs high DR wire process),WAAM:HR: £82/hDR: 1

12、 kg/hProcess 1:HR: £360/hDR: 7 kg/hProcess 2:HR: £170/hDR: 7 kg/hTypical BTF of High dep. Rate is 10,Specific cost of deposition(WAAM vs high DR wire process),WAAM:HR: £82/hDR: 1 kg/hProcess 1:

13、HR: £360/hDR: 7 kg/hProcess 2:HR: £170/hDR: 7 kg/hTypical BTF of High dep. Rate is 10This makes them break even for very high BTF (machined from solid),Specific cost of deposition(WAAM vs high DR wire

14、process),WAAM:HR: £82/hDR: 1 kg/hProcess 1:HR: £360/hDR: 7 kg/hProcess 2:HR: £170/hDR: 7 kg/hTypical BTF of High dep. Rate is 10This makes them break even for very high BTF (machined from solid)

15、WAAM’s BTF is <2,Specific cost of deposition(WAAM vs high DR wire process),WAAM:HR: £82/hDR: 1 kg/hProcess 1:HR: £360/hDR: 7 kg/hProcess 2:HR: £170/hDR: 7 kg/hTypical BTF of High dep. Rate i

16、s 10This makes them break even for very high BTF (machined from solid)WAAM’s BTF is <2Lots of room to be cheaper than machining,The problem of powder-bed processes,Machine cost: £500kDR: 0.1 kg/h100% powder

17、utilisation50% beam-on timeNo post-proc.,CASE STUDIES,Case studies,BAE Systems spar,Case studies,Bombardier rib,Case studies,Bombardier rib (steel),Case studies,A pylon mount,Case studies,15 kg aluminium wing rib (DR =

18、 1kg/h),Option 1:,Option 2:,CAD:,Case studies,Titanium wing frame,Example part 1,Non-recurring cost of tooling and programming: £1500,Example part 2,Non-recurring cost of tooling and programming: £1500,Conclusi

19、ons,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)H

20、igher 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 machiningIncreasing dep