After reading this article you will learn about:- 1. Meaning of Plant Layout 2. Need for Plant Layout 3. Objectives 4. Benefits 5. Factors 6. Tools and Techniques.
Meaning of Plant Layout:
The term ‘Plant Layout’ has been defined by many authors in so many ways A few of these definitions are given below:
According to Shubin, “Plant Layout is the arrangement and location of production, machinery, work centres and auxiliary facilities and activities (inspection, handling of material, storage and shipping) for the purpose of achieving efficiency in manufacturing products or supplying consumer services.”
According to Keith and Gubellini, “Plant layout deals with the arrangement of the physical facilities and the manpower which are required to manufacture a product or perform a service.”
According to J. Lundy, “Plant layout ideally involves the allocation of space and the arrangement of equipment in such a manner that overall operations costs be minimised.”
The above definitions indicate that plant layout is the physical arrangement of planned industrial operations. It implies the preparation of the entire stage of setting for the functioning of the plant designed to produce the specified goods or services.
Laying out in a suitable order of productive equipment with all its ancillary requisites in order to enable the personnel to efficiently operate the machines in pre determined sequence and effectively fulfill their assignments, is the idea involved in the concept of plant layout engineering.
The implications of the plant layout concept are indicated below:
(1) Designing the building with alterations and arrangements, sufficient and suitable to house the plant, equipment and appliances required for manufacturing or allied activities.
(2) Installing the machines at proper places with well prepared floor areas.
(3) Placement of plants, machines etc. in systematic sequence as per the order or work planned and programmed.
(4) Provisions of tools, appliances, stores, materials etc. required for operating the machines.
(5) Making adequate arrangements for service activities or auxiliary facilities for operations of the main plants and handling the equipment.
Need for Plant Layout:
Plant layout has become inevitable function of management due to far-reaching developments in the field of science, technology and their application to wide range of industrial and commercial activities.
Proper plant layout is necessitated by the following factors:
(1) Establishment of new plant to manufacture newly designed and developed products.
(2) Major expansion of the capacity of existing plants to meet additional load of demand.
(3) Incorporation of latest changes in technology, plant design, equipment etc.
(4) Need for increasing the efficiency of operations through radical as well as routine changes in design and methods of production.
Objectives of Plant Layout (or Essentials of an Ideal Layout):
Plant layout implying the development of physical equipment and facilities aims at integration of machines, materials and men for economical, productive operations.
As Shubin and Madeheim observe, “its objective is to combine labour with the physical properties of a plant (machinery, plant, services, handling equipment) in such a manner that the greatest output of high quality goods and services manufactured at the lowest unit cost of production and distribution will result.”
Systematic arrangement of plant and its ancillaries in accordance with the nature of the job to afford maximum convenience to the workers to operate the activities assigned to them is the basic objective of plant layout.
Since production is nothing but the movement of materials in different stages for conversion into finished products, plant layout is intended to fulfill the following fundamental objectives, which are also the criteria for an ideal layout.
(a) Providing facilities to receive the materials intended to be used in the manufacturing processes.
(b) Proper arrangement of machinery and equipment in each department to provide ample room to place materials within easy reach of the workers.
(c) Near accessibility (through proper routing) to stores centres and ensuring direct and continuous movement of stores materials to initial and subsequent operations.
(d) Free access to machines and assembly lines for quick delivery of materials within each department and for fast pick up of outbound material and wastes.
(e) Adequate storage facilities for materials in process between consecutive operations.
(f) Grouping of machines and departments in such a manner that movement of materials or job on hand between the successive operations is as short as possible with minimum of back tracking and needless handling.
(g) Stock-rooms and tool cabins with facilities for storing, recording and handling of materials, tools, etc. with minimum delay.
(h) Arrangement for packing and creating finished products instantly and automatically moving them to warehouses or different corners bound for different markets destinations.
(i) Arrangement of plant, tools and physical facilities consistent with maximum convenience, safety and health of workers.
Benefits of Plant Layout:
Plant layout planned according to the above noted objectives helps in attaining high productivity in the use of plant, equipment, labour and materials.
Its benefits can be summarised as under:
(i) Good plant layout facilitates accurate planning and control of production. A steady quantity of output is assured by proper layout of the productive capacity and its utilization. Idleness of machinery and man would be reduced to the minimum and production capacity would be maintained intact.
(ii) A sound layout ensures more efficient utilisation of machinery and men. It avoids congestion of production areas, overcrowding of personnel at the production spots and thus seeks to avoid delay in flow of product of eliminates bottlenecks that cause slowdown of the product-schedule. Thus overhead costs are reduced by continuous or uninterrupted use of machines and personnel.
(iii) The proper arrangement of equipment and plant operations would also minimise the effort and cost of materials handling.
(iv) Ideal plant layout secures better utilisation of available floor space. Well-designed plant layout economises the space required for production and reduces the unit cost and at the same time makes provision for additional floor space that may be felt necessary for expansion of productive capacity or diversification of product lines.
(v) Proper machine arrangement and service facilities will reduce “the overall time of work in process” by securing a smooth flow of work over the shortest routes of production. The work in process, the hold of stock, costs of inventory are all minimised by sound layout of plant operations in logical sequence.
(vi) A well designed layout is regarded as “a prerequisite to effective supervision.” Good layout makes it easy for the workers to carry out their assigned activities without the need for elaborate instructions and supervision.
Since the ideal plant layout involves standardised sequence of operations with greater degree of automatic movement of materials and operational processes, supervisory efforts and costs are obviously reduced to the minimum.
(vii) Good plant layout ensures safety to the operating personnel. The risks or hazards in mechanical operations at work centres are eliminated by safety devices built into the design of the plant and the allied layout of the equipment. Plant layout which incorporates safety element will result in lesser accidents and lesser loss of man-hours.
(viii) A good plant layout buttressed by wholesome service facilities, better working conditions like lighting, ventilation, noise-control etc. improves employee morale and enhances their efficiency in performance.
In short, plant layout brings about:
(a) Economies in materials and product handling;
(A) Reduction in number of accidents, loss of man-hours and wastage of equipment;
(c) Better utilisation of available floor space;
(d) Cut-back in idle capacity, superfluous work and delay in operations;
(e) Better provision for maintenance and inspection of the production capacity, work in process and the work completed;
(f) Reduction in cost of supervision; and
(g) improvement in personnel morale and response.
Factors Influencing the Plant Layout:
Let us analyse the important factors influencing a sound plant layout:
1. Nature of the Industry:
Manufacturing processes peculiar to different industries govern the type of plant layout to be arranged.
Industries are classified into following main types for the purpose of layout analysis:
(a) Synthetic Processes:
Synthetic process is one that combines several different ingredients or which involves assembling of numerous components for manufacturing a final product, e.g., soap, medicines, cement, automobiles radio- sets, shoes, etc.
(b) Analytical Processes:
Analytical process is one in which final product is obtained by successive processes that separate the final product from the mass of original material, e.g., oil refining.
(c) Conditioning Industry:
Is one where finished product is turned out by converting raw materials, e.g., sugar, textiles, etc.
(d) Continuous Process Industry:
This involves a sequence of processes serving as a prelude to release of the final product. It is characterised by an uninterrupted flow of operations from raw materials to the completion of the product through integrated facilities, e.g., cement, printing, flour mills, paper, etc.
(e) Intermittent Process Industry:
In this type of industry work is completed by stages. It is carried on in a series of distinct work centres. The final product is not turned out at one stroke in a single factory or work place. Final product is completed after different components are prepared at different centres, e.g., automobiles, radio-set, etc.
This classification should not be viewed as rigid because many industries are combinations of these processes, e.g., continuous synthetic industry like paper.
For continuous process Industries the layout is so arranged that work can be conducted in precise progression as per the sequence of planned operations. Successive operations are carried out in adjacent departments. Plant and equipment are to be laid out in such an order that raw materials are received at one end and passing through different stages finished products are turned out and released at the other end.
The movement of job-piece in the sequence should be well-planned avoiding delay and interruption. The span of movement should not be lengthy and the routes to the followed are to be systematically regulated. Such plant layout should reveal the interdependence of the individual processes in the continuous progression. Usually such movement is automatic and there should be built-in-sequential process.
In intermittent types of industry, plant layout should contain arrangements for the flow of different parts or components from respective departments to the central assembly shop at the required time. There should also be arrangements for storage of intermediate goods till they are diverted towards the assembling centres.
Handling through cranes, conveyor belts and other mechanical devices makes assembling quicker and easier. Complementary work centres should be located at convenient points but there should be arrangement for all the parts to convene on the central department for assembling into a finished product.
2. Influence of Location on Layout:
Layout is influenced by the geographical setting of the site where the enterprise is located. Machine arrangement is designed after taking into consideration the characteristics of the region with reference to power, personnel, climate, market etc.
“The size, the shape and topography of the site will affect the spotting of the building on the plot and for receiving and shipping and for best flow of production in and out of the plant.”
3. Managerial Policies:
Shubin points out that layout is influenced by policies framed by the management regarding the quality of products, size of the plant and the extent to which it is to be integrated, the plans if any for expansion and the quantity of inventory to be stored and the facilities to be provided for employees.
4. The Product and Its Influence on Layout:
The design and the specification of the product to be turned out and its physical and chemical characteristics including the size, the shape and bulk, would decide the pattern of layout of the plant and equipment. If the design of the product is of high quality involving complicated mechanical equipment, the layout should be in elaborate and continuous sequence.
If the design is simple, then the plant layout may consist of arrangements for small process. The type of the product classified from the point of demand would also influence the layout. If the product is luxury article, it is produced on a limited scale under conditions of process layout which minimise specialised equipment.
A product categorised as a necessity would provide the mass market and its layout should consist of a complex of specialised equipment to support longer volume of production. This justifies “the line layout” involving continuous flow of output in planned sequence.
Tools and Techniques for Plant Layout:
The layout engineering aims at proper placement of machines and equipment in order to ensure the turnover of the required output as per schedule. In planning a scientific layout, layout engineer has to devise certain tools, models and techniques as a prelude to actual installation of the machines, equipment and appliances.
The important tools used in layout engineering are process charts, flow diagrams, machine data cards, templates, machine models and plot places. These are meant to analyse production processes to be fitted into the plant layout.
1. Process Charts and Flow Diagrams:
The process charts are of two kinds:
(i) Operation Process Chart:
Any manufacturing activity is a composition of operations on set machines. Plant layout is arrangement of machine, operations wise. The process chart classifies the different operations implied in manufacturing a given product. It is generally preferred for use in planning a new layout. “An operation process chart sub-divides the manufacturing process into its separate operations and inspections.”
The chart is a summary of the manufacturing operation intended to show the planned order of work. Its aims are:
(a) To indicate the points at which materials are introduced, and
(b) To show the sequence of all operations and inspections excepting the materials handling process.
The chart is a symbolic plan of productive action. The usual symbols adopted in chart are: O-operation and □-inspection.
The circle indicates an operation and the square represents inspection involving the checking of quality of the output and verifying other details.
The operation chart brings out an overall picture of the process and serves as a basis for location of plant, tools etc., or for improvement of operations by elimination, combination or rearrangement. Where two or more allied articles are produced, products are grouped into categories which have common operational requirements.
A “generalised operation chart” can be prepared to indicate the process that produces related products.
(ii) The Flow Process Chart:
“The flow process chart is a graphic representation of all production activities occurring on the floor of the plant.”
While operation process chart shows only the operational points in the sequence, the flow process chart traces out the operations, along with transportation (movement), storage and delay. It charts out the movement of work from stage to stage, the storage points of work-materials, work-in-process, completed jobs, etc.
2. Flow Diagram or String Diagram:
Flow diagram represents the flow chart into a line diagram. A single line is drawn to scale on the floor plan to represent the physical movement of materials through the entire plant. The diagram graphically shows the operations, indicates the process facilities and may also spot out any superfluous process and bring about fruitful re-location of plant activities.
Flow diagram helps in deciding upon the natural and economical sequence of plant operations and arrangement of the production facilities.
3. Machine Data Cards:
Information pertaining to machine is collected and consolidated on a card to get the idea about the nature and capacity of the concerned machines before they are laid out on production line.
These cards contain the following information:
(a) Output capacity
(b) Space requirements
(c) Power needs
(d) Foundation details
(e) Suitable handling devices.
4. Templates:
Templates are cutouts to scale of various machines, equipment, the product or any other physical item, necessary to the process of work. They serve as visual aids in planning the layout.
Spriegel observes, “An excellent procedure in making a layout is to cut small-scaled templates of card-board or paper representing each machine or grouping machine in the process.” Templates are made out from a sheet of heavy paper, plywood, bristol board etc., which should be durable and usable for planning different layouts.
Templates are prepared to indicate the area required by machines, equipment, conveyors, benches, storage centres, etc. These areas and equipment may be shown by templates of different colours to facilitate easy identification. These templates are located in sequence on paper which give a total visual picture of the whole production-complex.
Template arrangement of machinery is an important step in planning the layout. As noted above, templates of machines and operations are fixed upon the floor plan indicating the sequence plotted on process charts in conformity with the criteria of general production plan.
Adequate space should be provided around each machine to facilitate smooth operation of the equipment, for the storage of goods in process, the use of handling devices and maintenance and repairs requirements. The convenience of the worker ensuring him ease in operation should also be borne in mind in plant arrangement.
The templates will enable the holding of trial layout. Revisions, if any, can be made by moving the templates and observing the changed sequence. After the template arrangement is finalised and found suitable, blueprints of the layout are taken out.
5. Machine Models:
Machine models are more elaborate and effective form of trial evaluation of the plant layout. Machine models are three dimensional moulds of machines, equipment, storage fixtures, handling devices etc.
Machine models are prepared when layouts for complex operations are to be planned. When expensive installations of machines are to be made, wooden models of such machines, allied apparatus, etc. are got prepared and fixed on to the floor plan, with storage and aisle space necessary for swinging or moving parts of the machines set in operation. Such models will give a clearer idea of the intended layout and flashes a realistic picture of the operations.
Templates will not unfold the entire perspective. The models with details of machine-name, weight, capacity noted thereon will give the layout engineer a precise vision of the planned operations.
In the words of Keith and Gubellini, “Scale models of men, machines, and all the physical units which enter into the layout problem are intended to achieve the same purpose as templates but do so more realistically.
Machine models help in visualisation of layouts even by non-technical personnel. Models are more durable and can be used for long. They can be photographed for comparative studies. But models are more expensive and time- consuming. Hence only in case of complicated layouts models are used in combination with two-dimensional templates.
6. Layout Drawings:
Layout drawings are floor-plan drawings made to scale. These drawings show the walls, partitions, columns, stairways, elevators, machines, storage areas, aisles etc. Drawings however do not set forth structural details. Coloured and shaded sketches may indicate shops or departments like receiving, storage, assembling, office areas, dispatch sections etc.
7. Plot-Plan:
It is said to show the overall arrangement and utilisation of the plant site, buildings and the adjoining areas.