layout and flow

8/3/2019 Layout and Flow

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What is layout?

Position of transforming resources

Allocation of tasks

The layout decision is relatively infrequent but important



General Objectives

Inherent safety

Length of f low Clarity of flow Staff conditions Management coordination

Accessbility Use of space Long term flexibility



Most practical layouts are derived from only four

basic layout types. These are:

Fixed-position layout

Functional layout

Cell layout

Product layout



Examples

o Motorway construction the product is too large to move

o Open-heart surgery patients are too delicate to move

oHigh-class service restaurant customers would object tobeing moved to where food is prepared

o Shipbuilding the product is too large to move

o Mainframe computer maintenance the product is too bigand probably also too delicate to move and the customer might

object to bringing it in for repair



Examples

Hospital Some processes (e.g. X-ray machines and laboratories) are required by several types of patient.Some processes (e.g. general wards) can achieve high staff and bedutilization.

M achining the parts which go into aircraft enginesSome processes (e.g. heat treatment) need specialist support (heat and fumeextraction).Some processes (e.g. machining centres) require the same technical supportfrom specialist setteroperators.

SupermarketSome products, such as tinned goods, are convenient to restock if groupedtogether.Some areas, such as those holding frozen vegetables, need the common

technology of freezer cabinets.



Examples

Some computer component manufacture the processing andassembly of some types of computer parts may need a special

area dedicated to the manufacturing of parts for one particularcustomer who has special requirements such as especially highquality levels.

Lunch products area in a supermarket some customers usethe supermarket just to purchase sandwiches, savoury snacks,cool drinks, yoghurt, etc. for their lunch. These products areoften located close together so that customers who are justbuying lunch do not have to search around the store.



Examples

Automobile assembly almost all variants of the samemodel require the same sequence of processes.

Mass-immunization programme all customersrequire the same sequence of clerical, medical andcounselling activities.

Self-service cafeteria generally the sequence of customer requirements (starter, maincourse, dessert,drink) is common to all customers, but layout also

helps control customer flow.



For N work centres there will N! different ways of arranging the work centres.

Information for Functional layout

oThe area required by each work centre.

oThe degree and direction of flow between each work

centre (for example, number of journeys, number of loads or cost of f low per distance travelled).

oThe ddegesirability of work centres being closetogether or close to some fixed point in the layout.



Step 1 Collect information relating to the work centres and the flow

between them.

Step 2 Draw up a schematic layout showing the work centres and the flowbetween them,putting the work centres with the greatest flow closest toeach other.

Step 3 Adjust the schematic layout to take into account the constraints of the area intowhich the layout must fit.

Step 4 Draw the layout showing the actual work centre areas and distances

which materials or customers must travel. Calculate the effectivenessmeasure of the layout either as total distance travelled or as the cost of movement.

Step 5 Check to see whether exchanging any two work centres will reduce

the total distance travelled or the cost of movement. If so, make theexchange and return to step 4. If not, make this the final layout.



The main product layout decisions are as follows:

What cycle time is needed?

How many stages are needed?

How should the task-time variation be dealt with?

How should the layout be balanced?



The Precedence diagram

Two heuristic rules have been found to be particularly useful in deciding this:

1. Simply choose the largest that will fit into thetime remaining at the stage.

2. Choose the element with the most followers: thatis the highest number of elements which can beallocated only when that element has beenallocated.

layout and flow

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