Plant Layout

1DR A K SHARMA, IITR

Plant Layout

DR A K SHARMA, IITR

Objectives of Facility Layout

1. OBJECTIVES FOR MANUFACTURING OPERATIONS LAYOUTS:

Provide enough production capacity. Reduce materials handling costs. Conform to site and building constraints. Allow space for production machines. Allow high labour, machine and space utilization and

productivity.

Provide for volume and product flexibility. Provide for employee safety and health. Allow ease of supervision. Allow ease of maintenance. Achieve objectives with least capital investment.

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2. (Addl.) OBJECTIVES FOR WAREHOUSE OPERATIONS LAYOUTS:

Promote efficient loading and unloading of shipping vehicles. Provide for effective stock picking, order filling, and unit

loading.

Allow ease of inventory counts. Promote accurate inventory record keeping.

DR A K SHARMA, IITR


3. (Addl.) OBJECTIVES FOR SERVICE OPERATIONS LAYOUTS:

Provide for customer comfort and convenience. Provide appealing setting for customers. Allow attractive display of merchandise. Reduce travel of personnel or customers. Provide for privacy in work areas. Promote communication between work areas. Provide for stock rotation for shelf life.



4. (Addl.) OBJECTIVES FOR OFFICE OPERATIONS LAYOUTS:

Reinforce organisation structure. Reduce travel of personnel or customers. Provide for privacy in work areas. Promote communication between work areas.

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Principles of Plant Layout

1. PRICIPLE OF OVERALL INTEGRATION:

That layout is the best which integrates the men, materials, machinery, supporting activities, and any other considerations in a way that results in the best compromise.

2. PRICIPLE OF MINIMUM DISTANCE MOVED:

Other things being equal, that layout is the best that permits the material to move the minimum distance between operations.

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3. PRICIPLE OF FLOW:

Other things being equal, that layout is the best that arranges the work area for each operation or process in the same order or sequence that forms, treats, or assembles the materials.

4. PRICIPLE OF CUBIC SPACE:

Economy is obtained by using effectively all available space both vertical and horizontal.

DR A K SHARMA, IITR


5. PRICIPLE OF SATISFACTION AND SAFETY:

Other things being equal, that layout is the best which makes work satisfying and safe for workers.

6. PRICIPLE OF FLEXIBILITY:

Other things being equal, that layout is the best that can be adjusted and rearranged at minimum cost and inconvenience.


Factors Influencing Plant Layout

Factors influencing any layout can be grouped into the following:

1. The Material Factor: Design,Variety,Quantity,The necessary operations and their sequence.

2. The Machinery Factor: Production equipment and tools,Their utilisation.

3. The Man Factor: Supervision,Service help,Direct workers.

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4. The Movement Factor: Inter and Intradepartmental transport,Hand handling at various operations, storages, andInspections.

5. The Waiting Factor: Permanent and temporary storages, andDelays.

6. The Service Factor: Maintenance,Inspection,Waste,Scheduling, andDespatching.

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7. The Building Factor: Outside and Inside building features,Utility distribution, andEquipment.

8. The Change Factor: Versatility,Flexibility, andExpansion.

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Factors Influencing Plant Layout Relation of Quality to Type of Layout:

Quality is fixed responsibility of individual workers.More skilled workers requiring fewer inspections.

Fixed position

Interdependental inspection and friction over quality.Good responsibilities for centralised or semicentralised inspection.First piece and setup inspection, and floor inspection during runs are usual.

Process

Hard to pin down quality responsibility.Bad work will interrupt continuity and starve subsequent operations.Inspection of tools and gauges before production is far more important.Less skilled workers, but fewer errors because of standardized work and job specialization.Decentralized inspection with inspectors holding the rate of production pace.

Product or Line

Relation to QualityType of Layout


Layout Design

Phases in Layout design:

Facility layout design consists of three major phases:

Phase I: Arrangement of various departments and offices basically based on the adjacency of various departments and offices with respectto each other.

Phase II: Arrangement of various equipment, machinery, supporting services, material-handling devices, work centers etc. within a particular department.

Phase III: Implementation of the layout developed in phases one and two.

DR A K SHARMA, IITR

Major Steps in Layout Design

1. Statement of the problem

Objectives, Scopes.

2. Collection of basic data on

sales forecast, production volume, production schedules, part lists, operations to be performed etc.

3. Calculation of production rate and equipment requirements

4. Data analysis and its presentation in the form of various charts .

5. Calculations of space requirements and allocation of areas

6. Development of block plan, plot plan, and detailed layout.

7. Evaluation, selection, and installation of layout.

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Collection of Data

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Equipment Requirements

S QF = --------------

E H Rwhere,F = Pieces of equipment required per shiftS = Standard time (minutes) per unit producedQ = Number of units to be produced per shiftE = Actual performance expressed as % of standard timeH = Amount of time (minutes) available per machineR = Reliability of machine in %.



Manpower Requirements

S QM = ------------

H where,M = Number of persons required per shiftS = Standard time (minutes) per unit producedQ = Number of units to be produced per shiftH = Amount of time (minutes) available per shift

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Major Steps in Layout Design Data Presentation TechniquesFive Major Flow Patterns:

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Flow Process Chart

This chart summarizes the flow and activity of a component through a procedure in terms of sequence of operation, transportation, inspection, delay and storage.

It includes information about time required and distance moved.

Information are obtained from the process design department in the form of a route sheet.

A separate route sheet is required for each part. Flow process charts are used for high volume products.

Various symbols are used as an aid in developing a flow process chart.

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Route Sheet



Data Presentation Techniques

Flow Charts:

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Multi-product Process Chart

Multi-product process chart is used when a large variety of items are produced (normally between 6 to 10) and the volume of production is medium.

A multi-product process chart is used to combine the operation process charts for more than one product.

In a multi-product process chart only two symbols are used, circle for operation and rectangle or square for inspection.

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Multi-product Process Chart

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From-To Chart

From-to chart (or Travel chart) is used to represent the amount of flow between various departments.

It indicates the distances and number of moves between different pairs of departments.

The pair of departments that has the largest value of either the distance between them or the moves between them must be placed closest to each other.

Thus, the material handling between the departments can be reduced.

The from-to chart is helpful in the process type of layout design; but is not applicable to a product layout.


Activity Relationship Chart

An activity relationship chart shows the relationship of every department, office, or service area with every other department and area.

The REL chart represents the importance of adjacency between departments using codes.

These codes are called closeness codes and must be associated with pre-specified reason codes. Reason codes are not standard codes.

The facility planner, to aid in justifying the selection of closeness codes, establishes such codes.

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Activity Relationship Chart

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Estimation of Space

Space requirement involves space required by

offices,

equipment,

workstations,

warehouse,

maintenance,

power generation and/or distribution,

material handling,

sewage treatment, if any

recreation etc.

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Development and Presentation of Layout

Plot Plan:


Development and Presentation of Layout

Block Plan:

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Construction of Detailed Layout

Any one of the three methods is used:

1. Drafting or sketching

2. Templates

3. Models.

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Checking the Layout

To check the proposal against the objectives of plant layout. The layout should be checked against the following

objectives:

1. Overall integration

2. Minimum distance moved

3. Flow of the product

4. Space utilization

5. Employee satisfaction and safety

6. Flexibility.

DR A K SHARMA, IITR

Installation of Layout

A layout installation usually takes place over a period of time. The layout may occur in the following phases:

1. Plan (sequence of moves, making up inventory of everything to be relocated, set up time tables with specific date and time etc.)

2. Provide (outsourcing, good communication, get moving equipment etc.)

3. Prepare (new location, foundations, partitions, paintings etc.)

4. Move (move as close to installation as possible)

5. Install (install and flag equipment ready for installation inspection)

6. Start up (be sure for placement, hook-up etc.) and

7. Clean up (set deadline for clean up to avoid temporary feel).


Installation of Layout A typical scheduling of layout installation:

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Evaluation of Layouts

Evaluation means the assessment of each alternative in terms of the criteria decided earlier.

Evaluation provides the basis for analyzing the various layouts and helps in selecting the best layout among them.

The best layout, in fact, is the BEST COMPROMISE. No standard evaluation procedure does exits.

DR A K SHARMA, IITR


The following systematic approaches are in practice:1. Pilot plant,

2. Cost comparison,

3. Productivity evaluation,

4. Space evaluation,

5. Sequence demand straight line,

6. Sequence demand non directional,

7. Factor analysis,

8. Ranking, and

9. Analysis of pros and cons.

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Productivity Evaluation

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Space Evaluation

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Sequence Demand straight line

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Floor plan of the area assigned

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1603006016043002601

DemPosMean

For example, DemandPosition Mean for Centre C:

DemDemPos

DemPosMean ii

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Demand position graph for Press C

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The final layout developed by sequence demand method

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Sequence Demand Non-directional

PPROBLEM : A drill press, a turret lathe, a turret lathe, and an inspection station are to be located in an established layout. There are four areas available within this layout for locating the new machines. Figure shows the location of these areas and indicates the distances between each.

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The number of trips between the various combinations of machines taken two at a time is shown schematically in the Figure below.

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SOLUTION: A load-path matrix as given by Wimmert can be developed as given below:

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SOLUTION:

Here, all combinations of the possible locations, taken two at a time, are plotted across the top of the matrix arranged so that the feet between the locations is monotonic nondecreasing from left to right.

Along the vertical axis of the matrix the combinations of the machines, taking two at a time, are plotted so that the number of trips between the centers is monotonic nonincreasing from top to bottom.

Thus, the maximum load-path is in the north-east corner of the matrix, while the minimum at the south-west corner.

This fact enables the designer in eliminating the undesirable alternatives.

The resulting layout can be presented schematically as below:

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SOLUTION: The resulting layout can be presented schematically as below:

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Factor Analysis Method

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Ranking Method

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OTPTIMIZING EVALUATION:

1. Linear Programming

2. Line Balancing

3. Level Curve Method

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Plant Layout