Plant Layout Problem

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FACILITY LAYOUTPROBLEM


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FACILITY LAYOUT

PROBLEMOnce a firm hasdecided where a

facility will belocated, the nextimportant decision is

the Arrangement ofpeople andEquipment withinthe facility.


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FACILITY LAYOUT

PROBLEMFacility Layoutproblem involves thelocation of departments (or sections)

within the facility AND the arrangementof people and equipment within eachdepartment.


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FACILITY LAYOUT

PROBLEM The layout decision will certainly affect

the Flow of materials, in-plant

Transportation cost, equipmentutilization, and general productivity andeffectiveness of the business.

Therefore, plant layout should becarefully arranged, AND It must satisfyspecific objectives.


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FACILITY LAYOUT

PROBLEM Usually the layout is planned to minimize a

particular criterion:

For example, minimizing total traveling time,total cost, total delays, etc.

There are also situations in which the layoutmay be designed to maximize a criterion:

For example, maximize quality, flexibility, orspace utilization.


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Layout Types

- Process Layout:

- Fixed Layout:

- Product Layout:


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Process LayoutSimilar pieces of equipment thatperform similar functions are grouped

together. For example; all drillmachines are grouped and placedtogether.


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Product LayoutThe pieces of equipment required tomake a Particular product are grouped

together, as in an Automobile assemblyline.


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Fixed LayoutThe equipment is brought to the objectbeing processed, and the object does

not move. Example; houseconstruction.


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Layout Types The selection of the layout type depends on:

1) the firms operations strategy,

2) the forecast volume of production,

3) the physical characteristics of the product,

4) availability of the resources

5) the type of process technology that will beused.


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Layout Types Regardless of the layout type selected,

Todays harsh competition forces

manufacturer firms to build new facilities thatcan be easily transformed to other types offacilities.

This means that the companies are becoming

more flexible in changing their facility layoutsin order to respond future needs of theorganization.


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Quantitative Models for

Facility Layout DecisionsArranging people and equipment in a

facility can quickly become complex.

The greater the variety of ways inwhich products are carried through thefacility, the greater the number of

potential layouts.


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Quantitative Models for

Facility Layout Decisions When there are many alternatives to

consider, the analytic models that we

describe in the following are helpful.


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Minimizing

Communication CostIf there isconsiderable traffic

between pairs ofdepartments, a firmmay want toMinimize the cost of

inter-departmentaltravel.


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Example Frontec Company wants to arrange

Four of its departments in a Row so

that the Total Distance Traveledbetween Departments is minimized.

This part of the building will contain

four departments arranged in a row.


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Example

Frontec wishes to minimize the totaldaily inter-departmental distance

traveled. The number of daily communications

between each pair of department is

shown below:


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Example


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Example

Assume that adjacent departments are 20feet apart.

We will use a trial-and-error approach to thisproblem.

Assume that we selected the followingconfiguration for the departments: A-B-C-D.

For this configuration, Total communicationcost (based on distance) is as follows:


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Example


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Example


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Example

In terms of total daily communicationdistance, (B-A-C-D) is the preferred

alternative. But the firm has to consider all of the

24 (4! = 4x3x2x1) possible

configurations before it knows if this isthe optimal configuration.


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Example

This trial-and-error approach becomestime-consuming as the number of

departments increases AND It alsobecomes complex when the cost ofcommunications vary between

departments.


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Systematic LayoutPlanning

Systematic Layout Planning (SLP) is anorganized approach to facility Layoutplanning.


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Systematic LayoutPlanning

The heart of SLP is the ActivityRelationship Chart and Diagrams that

neatly summarize vast amounts ofquantitative and Qualitativeinformation.


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Example

A small accounting Firm, GUNTAAccounting, has rented Space in a new

one-floor building. The firm has allocated 6000 square

meter to its seven departments as

follows:


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Example


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Example

In the first step of Systematic LayoutPlanning, we analyze interactions

between departments AND we assessthe desirability of placing departmentstogether.


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Example

The firm has carefully analyzed itsoperations to Determine the importance

of Locating specific departments CloseTogether.

The results of this analysis are

summarized in the followingActivityRelationship Chart:


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Example


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Example


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Example


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Example

This Activity Relationship Diagram isessentially an Illustration of the

Information Contained in the ActivityRelationship Chart.

All departments in this diagram areRepresented by equalsize boxes.

The next step is to anticipate the spacerequired for each Department.


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Example

Since the space assignments are givenbefore, the following Activity

Relationship Diagram shows the relativeSizes of Each Department:


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Example


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Example

In this stage, there are no restrictionson the length and width of each

department In the final step, we should develop and

evaluate several alternative layouts,

while keeping in mind the PracticalLimitations.


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Example

Some examples of Practical Limitations in thiscase were as follows:

1- It is considered that offices for partners(2), the meeting room (7) and the receptionarea (1) should be close to each other.

2- It is important that the juniors (4) and the

managers (3) be close together.


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Example

As a result of these limitations, Analternative floor planis developed as

follows:


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Example


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Example

This floor plan may be revised many timesuntil the best layout has been found.

Usually departments are positioned one byone, Beginning with the department withthe Highest A or E ratings.

Systematic Layout Planning is essentially an

organized Trial-and-Error Approach.


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Example

Therefore, unless all possible layouts areconsidered, There is no way to know if an

Optimal Solution been Reached. However, there are a number ofHeuristics

that can be used to Generate good solutionsQuickly.

Heuristics: Trial-and-error solutions that donot give optimal solution but easy to apply.


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Example

Layout planning Heuristics are of twotypes:

- Those which start with an initial layoutand proceed to modify it (These arecalled Improvement Heuristics), and

- Those which start the Layout analysisfrom scratch (Construction Heuristics.)


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Example

The most widely known algorithmrequiring an Initial Layout developed by

hand is the Computerized RelativeAllocation of Facilities Technique(CRAFT).

CRAFT was developed for situations inwhich Materials Handling Costs were amajor consideration.


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Example

Therefore, its goal is to Minimize the TotalCost of Moving Items between Departments.

It attempts to improve an Initial Layout byswitching the locations of pairs ofdepartments.

It begins with one department, AND one by

one Analyzes the effect on total travel cost ofswitching those departments.


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Example

While the Original CRAFT was used only forsingle-story buildings,

An extension of CRAFT called SPACECRAFTcan handle multistory buildings.

Some examples of Construction Heuristicsinclude CORELAP (Computerized Relationship

Layout Planning) and ALDEP (AutomatedLayout Design Program).


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Example

These heuristics start with an emptyfloor area and proceed to fit

departments.ALDEP can be used in a multistory

building. It generates many alternative

layouts.


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Example

CORELAP on the other hand, can layout only single story buildings.

Both programs use closeness codesdefined in the Activity RelationshipCharts.


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Example

A Final Note: In general, Becausetechnologies change rapidly, facilities

and technologies must be modified tosuit the market requirements.


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Example

It is better to have Low-cost,extendable physical facilities Than to

modify existing structures. These extendable facilities can be

replaced with more suitable structures

designed for the life of the changingproducts or services.


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Storage and WarehouseLayouts

In a storage Layout, Themost important criterion

is the Ease of Storageand Retrieval.

Aisles in a storage needto be little wider than theequipment for movingand handling stock.


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And equipment should be selected thatallows the Fullest use of the internal

Height of the Building. There are differences betweenAutomated and Manually picked storehouses.

In a storehouse using AutomatedStorage and Retrieval Systems (AS/RS),


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- There need to be no or little Light.

- The aisles need to be wider than the largestdimension of the biggest stock item.

- Buildings can be higher, and there norestrictions about the weights.

- A crane is dedicated to each aisle, picking

from either side.- Therefore, a crane breakdown means no

access to the affected aisle until it is repaired.

d h


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In a manual system, on the other hand,

- Good lightening levels are required.

- Heavy items should be stored at kneelevel or lower.

- Storage package sizes should be no

heavier than one person can handle.

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Plant Layout Problem