a kanban milk-run coordinated milk-run application

8/13/2019 A Kanban Milk-Run Coordinated Milk-Run Application

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Problem Definition

A material supply system design that serves assembly lineswill be designed.

Delivery of parts to the stations of an assembly line must

occur on a JIT basis: our problem is called JITVRP.

This material supply system called: Milk-run System A single central warehouse

Stations of the line have a continuous demand rate (Qi)!

At all times, theressome demand of components to be satisfied.

Service of the milk-run system is periodic.

We must find the service period!


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Problem Definition

Ex: Qi=10 parts/hr

If service period=2 hrs, Delivery to stat-i=20 partsat each cycle.

If period=4 hrs, delivery to stat-i=40 parts

So as period increases, delivery quantitiesincrease!

But, vehicle capacity is limited. Therefore, service period affects route

construction!


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Activities in a Milk-Run Cycle

When a station starts to consume parts from acontainer, it issues a Kanban, indicating itsrequirement of one full container.

The vehicle collects all of the Kanbans & emptycontainers released by stations.

Then kanbans are scanned in Barcode station.

Orders sent to the Warehouse. Vehicle goes to the Warehouse by holding

Kanbans & empty conts.


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Activities in a Milk-Run Cycle

Vehicle collects full containers from the warehouse &

starts delivering the full containers to the stations

assigned to its route.

While delivering the full containers at a station's bufferarea, the vehicles also pick up the empty containers

where the Kanbans are attached.

By the end of the route, the vehicle returns to the

warehouse holding the empty containers with Kanban.

Full containers must be delivered to the buffer, until

the buffer stock is exhausted.


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Route Construction Example

Stations Demand Rate Period Deliveries Routes

1 10/hr 1 hr 10 A

2 5/hr 5 A

3 7/hr 7 A

4 5/hr 5 B

5 3/hr 3 A

6 20/hr 20 B

Vehicle/route capacity= 25 (fixed!).

Stations Demand Rate Period Deliveries

1 10/hr 1.5 hr 15 A

2 5/hr 7.5 A

3 7/hr 10.5 B

4 5/hr 7.5 B

5 3/hr 4.5 B

6 20/hr 30 C


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Route Construction Algortihm


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Objective of RCA

Construct routes & determine service

period, such that total material

handling & inventory holding cost isminimized!


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Constraints

Trip time of a route= Loading unloading times

spent in the stations + material transportation

times

Trip time of a route


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Route

Construction

Algorithm (RCA)


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Candiate Service Times & Costs

2 routes: V=1, V=2

0.75 hr service periodminimized total cost!

Unit material handling

cost (UMHC) is $4/h.

UIHC for the parts ofthe stations 1, 3, 4, 5,

6, 7, 8, 9, 10, 11, 12, 13are $2/h per container.

UIHC of panel parts ofstation 2 is $10/h perpallet.


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Constructed Routes

Stations 1-13 : First route. The total of the delivery quantities to these stations does

not violate the milk-run vehicle capacity, and there is nobuffer space violation.

Station 2: Panel component: Second route. Panel component: a great volume in one pallet could not

be included in the 1st route, and a second route had to beconstructed.

Moreover, since the panel parts are fragile, the pallets

of these are wished to be pulled by the tow truckprivately, and could not be appended to the milk-runtrailers.


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Service/Stop Points of Routes


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Constructed Routes

a kanban milk-run coordinated milk-run application

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