Logistics cost

1
Logistics cost
2
Componenti del costo logistico

• Costi di trasporto (in ingresso, intra-company.
  in uscita) Costi di magazzino (immagazinamento
  e deposito dei prodotti, localizzazione del
  deposito e della azienda) Costo di mantenimento
  scorte (capitale per materie prime. WIP2,
  prodotti finiti, scarti) Costi di
  acquisto/produzione lotti
• (movimentazione materiali, messa a punto linee)
• Costo degli imballi per trasporto e
  movimentazione
• (pallet, materiali da imballaggio, altri) Costi
  amministrativi/ di struttura (management. staff,
  sistemi informativi)

3
Time space diagrams

• Consider a simple Product to Consumption Network
• Primary Tradeoffs
• Moving (Handle, Transport)/Holding (Rent,
  Inventory)

4
Cumulative count curve
Shipments Arrivals

• Horizontal distances
• Transit time tm
• Headway hi

Cumulative Count of Items
nw
nt

• Vertical distances
• Items waiting transport nw
• Items in transit nt
• Items at destination nd

hi
D
tm
D
Time
5
Logistics cost LC function

• LC (per item) Holding Costs Moving Costs
• Holding Costs Rent Cost Inventory Cost
• Moving Costs Transport Cost Handling Cost
• LC (per item) (R I) (T H)

6
Rent cost R (/item)

• Function of max inventory
• Captures facility costs
• Not affected by the item by item flow
• AnnualRentCost cr Dhmax
• R cr hmax
• D Annual demand (items/time)
• cr Rent cost (/item-time)
• hmax Maximum headway (time)

7
Inventory cost I (/item)
8
Transport cost T (/item)
Fixed and variable components on shipment basis
ignores when and what each shipment contained. T
decreases with increase in average shipment
size. But this is missing some key drivers . .
. ShipmentCost cf cvv nShipmentCost Sn(cf
cvvi) ncf cvSnvi ncf cvV T cf (n/V) cv
cf /v cv
9
Nomenclature
10
Transport costs T headways h
11
Transport costs and distance
Fixed costs cf are variable with number of
delivery stops ns and distance d Variable costs
have a fixed component and a linear component
variable with distance d cf cfs (1 ns )
cfdd cv cvs cvdd T cf /v cv T cfs (1
ns )/v cfdd/v cvs cvdd Marginal cost of an
additional item ignore cvd
12
Transport costs in relation to capacity

• ft(v) is sub-additive ft(v1v2) ft(v1)ft(v2)
• cvvMAXltltcf

13
Transport costs with multiple modes
14
Handling costs H (/item)

• Loading items into boxes, pallets, containers,
  etc.
• If handled individually linear with each item
• If handled in batches fixed variable
  components
• HandlingCost H cfh cvhvh
• vhcapacity (items) for load unit h

15
Moving costs T H (/item)
T H cf /v (cv cfh /vhMAX cvh) T H
cfs(1 ns)/v cfdd/v cvs cfh/vhMAX
cvh Generally handling costs are subsumed within
transport costs as long as VgtgtvhMAX (total
shipment size is much greater than pallet)
16
Total logistics cost LC function
17
Total logistics cost function
VMAX Maximum capacity for transport mode (items)