FACILITY LAYOUT PROBLEM

Mohamed Iqbal Pallipurath

FACILITY LAYOUT PROBLEM

Once a firm has decided where a facility will be located, the next important decision is the Arrangement of people and Equipment within the facility.

FACILITY LAYOUT PROBLEM

Facility Layout problem involves the location of departments (or sections) within the facility AND the arrangement of people and equipment within each department.

FACILITY LAYOUT PROBLEM

The layout decision will certainly affect the Flow of materials, in-plant Transportation cost, equipment utilization, and general productivity and effectiveness of the business.

Therefore, plant layout should be carefully arranged, AND It must satisfy specific objectives.

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

layout may be designed to maximize a criterion:

For example, maximize quality, flexibility, or space utilization.

Layout Types

- Process Layout: - Fixed Layout: - Product Layout:

Process Layout

Similar pieces of equipment that perform similar functions are grouped together. For example; all drill machines are grouped and placed together.

Product Layout

The pieces of equipment required to make a Particular product are grouped together, as in an Automobile assembly line.

Fixed Layout

The equipment is brought to the object being processed, and the object does not move. Example; house construction.

Layout Types

The selection of the layout type depends on: 1) the firm’s operations strategy, 2) the forecast volume of production, 3) the physical characteristics of the product, 4) availability of the resources, and 5) the type of process technology that will be used.

Layout Types Regardless of the layout type selected,

Today’s harsh competition forces manufacturer firms to build new facilities that can be easily transformed to other types of facilities.

This means that the companies are becoming more flexible in changing their facility layouts in order to respond future needs of the organization.

Quantitative Models for Facility Layout Decisions

Arranging people and equipment in a facility can quickly become complex.

The greater the variety of ways in which products are carried through the facility, the greater the number of potential layouts.

Quantitative Models for Facility Layout Decisions

When there are many alternatives to consider, the analytic models that we describe in the following are helpful.

Minimizing Communication Cost

If there is considerable traffic between pairs of departments, a firm may want to Minimize the cost of inter-departmental travel.

Example

Frontec Company wants to arrange Four of its departments in a Row so that the Total Distance Traveled between Departments is minimized.

This part of the building will contain four departments arranged in a row.

Example

Frontec wishes to minimize the total daily inter-departmental distance traveled.

The number of daily communications between each pair of department is shown below:

Example

Example Assume that adjacent departments are 20

feet apart. We will use a trial-and-error approach to

this problem. Assume that we selected the following

configuration for the departments: A-B-C-D. For this configuration, Total communication

cost (based on distance) is as follows:

Example

Example

Example

In terms of total daily communication distance, (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 is the optimal configuration.

Example

This trial-and-error approach becomes time-consuming as the number of departments increases AND It also becomes complex when the cost of communications vary between departments.

Systematic Layout Planning

Systematic Layout Planning (SLP) is an organized approach to facility Layout planning.

Systematic Layout Planning

The heart of SLP is the Activity Relationship Chart and Diagrams that neatly summarize vast amounts of quantitative and Qualitative information.

Example

A small accounting Firm, GUNTAŞ Accounting, has rented Space in a new one-floor building.

The firm has allocated 6000 square meter to its seven departments as follows:

Example

Example

In the first step of Systematic Layout Planning, we analyze interactions between departments AND we assess the desirability of placing departments together.

Example

The firm has carefully analyzed its operations to Determine the importance of Locating specific departments Close Together.

The results of this analysis are summarized in the following Activity Relationship Chart:

Example

Example

Example

Example This Activity Relationship Diagram

is essentially an Illustration of the Information Contained in the Activity Relationship Chart.

All departments in this diagram are Represented by equal size boxes.

The next step is to anticipate the space required for each Department.

Example

Since the space assignments are given before, the following Activity Relationship Diagram shows the relative Sizes of Each Department:

Example

Example

In this stage, there are no restrictions on the length and width of each department

In the final step, we should develop and evaluate several alternative layouts, while keeping in mind the Practical Limitations.

Example Some examples of Practical Limitations

in this case were as follows: 1- It is considered that offices for

partners (2), the meeting room (7) and the reception area (1) should be close to each other.

2- It is important that the juniors (4) and the managers (3) be close together.

Example

As a result of these limitations, An alternative floor plan is developed as follows:

Example

Example This floor plan may be revised many

times until the best layout has been found.

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

Systematic Layout Planning is essentially an organized Trial-and-Error Approach.

Example Therefore, unless all possible layouts

are considered, There is no way to know if an Optimal Solution been Reached.

However, there are a number of Heuristics that can be used to Generate good solutions Quickly.

Heuristics: Trial-and-error solutions that do not give optimal solution but easy to apply.

Example

Layout planning Heuristics are of two types:

- Those which start with an initial layout and proceed to modify it (These are called Improvement Heuristics), and

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

Example

The most widely known algorithm requiring an Initial Layout developed by hand is the Computerized Relative Allocation of Facilities Technique (CRAFT).

CRAFT was developed for situations in which Materials Handling Costs were a major consideration.

Example Therefore, its goal is to Minimize the

Total Cost of Moving Items between Departments.

It attempts to improve an Initial Layout by switching the locations of pairs of departments.

It begins with one department, AND one by one Analyzes the effect on total travel cost of switching those departments.

Example While the Original CRAFT was used only

for single-story buildings, An extension of CRAFT called

SPACECRAFT can handle multistory buildings.

Some examples of Construction Heuristics include CORELAP (Computerized Relationship Layout Planning) and ALDEP (Automated Layout Design Program).

Example

These heuristics start with an empty floor area and proceed to fit departments.

ALDEP can be used in a multistory building. It generates many alternative layouts.

Example

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

Both programs use closeness codes defined in the Activity Relationship Charts.

Example

A Final Note: In general, Because technologies change rapidly, facilities and technologies must be modified to suit the market requirements.

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 changing products or services.

Storage and Warehouse Layouts

In a storage Layout, The most important criterion is the Ease of Storage and Retrieval.

Aisles in a storage need to be little wider than the equipment for moving and handling stock.

Storage and Warehouse Layouts And equipment should be selected

that allows the Fullest use of the internal Height of the Building.

There are differences between Automated and Manually picked store houses.

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

Storage and Warehouse Layouts

- There need to be no or little Light.- The aisles need to be wider than the largest

dimension of the biggest stock item.- Buildings can be higher, and there no

restrictions 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.

Storage and Warehouse Layouts

In a manual system, on the other hand,

- Good lightening levels are required.- Heavy items should be stored at knee

level or lower.- Storage package sizes should be no

heavier than one person can handle.