Plant Layout

Importance of Site Selection

·         The location has great effect on the success or failure for the operation of a plant.

·         Therefore, it should be based upon a careful consideration of all factors that are essentially needed in efficient running of a particular industry.

·         The necessary factor in the selection of plant location very among industries and with changing technical and economic conditions.

·         Some industries have tended to follow their markets.

·         Site location is not an easy problem because if the selection is not proper then all money spent on factory building, machinery and their installation etc. will go as waste and the owner has to suffer a great loss.

·         Therefore will go as waste and the owner must consider technical, commercial, financial aspects while which may provide maximum advantages.

·         The problem of the selection of a factory can be solved in the following two stages:-

(a)    The general location of the factory.

(b)   The selection of a particular site.

·         The general location of the factory:- following factors must be considered in this respect:

(a)    Availability of Raw Materials:- As far as possible, the site selected should be near the source of raw materials, so that the cost of transportation may be minimum.

(b)   Proximity to Markets:-  The cost of transporting finished goods, advertising and distribution, etc. will be greatly reduced if the factory is situated near the market. So the goods can be sold at cheaper rate.

(c)     Transport Facility:- Transportation cost of raw material plays an important role, especially when the raw materials are bulky and of low value.

(d)   Availability of efficient and cheap labour:- while selecting a site, it is necessary to consider that whether right kind of labour at suitable rates is available or not, because labour cost is an important item of the total production cost.

(e)    Availability of power and fuel:- Earlier, the industries were situated near coal mines or places to which coal could be carried easily and cheaply, but now due to development of electric power and high tension grid system this factor has not much effect.

(f)    Climatic and Atmospheric condition:- It is governing factor for several industries, as cotton industry, require moist climate that is why, most of the textile mills have been located at Bombay and Ahmedabad.

(g)   Availability of Water:- All factories need soft and pure water, hence its search should be made whether good quality of water is available or not. If not available, then its cost of transport has to be given prime consideration.

(h)   Availability of Capital:- The supply of capital is an important factor on the rate of development of a factory. Amount of capital available helps in determining the size of the plants and its future plans.

(i)     Social and Recreational facilities:- Usually big factories, are located away from the public, social and recreational centres. During off hours, the employees require some social and recreational amenities which are the necessity of life.

·         Selection of Actual site:- the most important factors in this respect are:

(a)     Availability of cheap land to build and expand the plant.

(b)   The cost of levelling the land and providing foundations, subsoil conditions for foundation and drainage.

(c)    The cost of bricks, sand, cement, lime, steel and other materials required for construction.

(d)   Facilities for the upkeep and general maintenance.

(e)    Facilities for transport, in getting and sending materials.

(f)    Facilities for housing the workers and if necessary, their transport from their place of residence to the work sites.

(g)   Cost of laying the water supply and providing sewage and disposal work.

(h)   Cost of installation of electricity, gas and other facilities, etc.

(i)     Cheap possibilities for disposing of trade waste.

(j)     Any restriction placed by the town planning department or local bye-laws be well studied.

Principles of Plant Layout

ð  There are six basic principles of “Best Layout”. These are:-

(1)   Principle of over-all integration:- The best layout is one which integrate the man, materials, machinery, supporting activities and any other such factors that results in the best compromise.

(2)   Principle of minimum distance:- Other things being equal, the best layout is one in which men and materials have to move the minimum required distance.

(3)   Principle of flow:- The best layout is one which arranges the work area for each operation or process in the same order or sequence that forms treats or assembles the materials.

(4)   Principle of cubic space:- The best layout is one in which all the available space both vertical and horizontal is most economically and effectively used.

(5)    Principle of satisfaction and safety:- The best layout is one which makes work satisfying, pleasant and safer for workers.

(6)   Principle of flexibility:- It means, the best layout is one which can be adopted and re-arranged at a minimum cost with least inconvenience.

Objectives for Plant Layout

ð  These are:-

a)      To produce better quality of products.

b)      Maximum utilisation of floor area.

c)      To reduce internal transport from one operation to the next as much as possible.

d)     Lighting and ventilating.

e)      Lower cost of scrap and waste.

f)       Fewer accidents.

g)      Minimising production delays.

h)      Space for future expansion.

i)        Safety of equipment and personal.

j)        Better working conditions for both executive and operative employees.

k)      Avoidance of unnecessary change.

l)        Saving of cost.

m)    Easy supervision.

n)      Neatness.

o)      Proper production control.

p)      To eliminate waste effort for speeding of production.

Methods of Plant Layout

ð  keeping in view the type of industry and volume of production, there can be following methods of layout:-

(A)   Line or Product Layout:-

ð  This type of layout is very popular in mass production.

ð  In this layout only one type of product is produced in an operating area.

ð  In order to justify the line layout, the product must be standardised and manufactured in huge quantities.

ð  The machines in such layout are arranged in the order in which they are to be used.

ð  The operations are performed in a sequence.

ð  This arrangement is also known as the “Synthetic system” of manufacture.

ð  For example, suppose a factory manufactures reamers, in the department, there will be group of lathes to turn the reamer blanks, the lathes will be followed by the milling machines which square the shank and mill the flutes; next to the milling machines will be furnaces for heat treating the reamers and last will come the grinding machines to do the finishing. Fig.1 shows an arrangement of this type.

                                           

ð  Suitability:- This is suitable for continuous process industries such as car or automobile manufacturing or chemical industries.

ð  Advantages:-

(1)   It lowers the overall manufacturing time as product under it proceeds rapidly from operation without any handling.

(2)   Less space is needed for placing machines.

(3)   There is less of handling and transportation.

(4)   There is less work-in-process.

(5)   Better utilisation of machines and labour.

(6)   It minimises counting, inspecting and clerical work etc.

(7)   There is smooth flow of materials.

(8)   Promises for supply of products to customers are more reliable.

(9)   Production control is simplified greatly.

ð  Disadvantages:-

(1)   When the model or type changes, the layout of machinery also requires a change.

(2)   All machines in the arrangement cannot be used to their maximum capacity.

(3)   The manufacturing cost rises with a fall in the volume of production.

(4)   If one or more lines are running light, there is great machine idleness.

(5)   Specialised and strict supervision is needed.

(6)   If any of the machines in the stop breaks down the other machines have to remain idle.

(7)   For expansion process, it is not possible to add more machines.

(8)   Each worker performs job on a particular machine, so he is not skilled for other machines or operations.

(B) Functional or Process Layout:-       

ð  Under this arrangement each department or section is responsible for carrying out a particular process and not a particular product as under line type layout.

ð  There is assembling of similar operations in each department or section.

ð  Machines in this type of layout are arranged on functional basis.

ð  This type is also called “Analytical Layout”.

ð  For example in factory manufacturing reamers, there may be four departments, the lathe, milling, the heat treatment and the grinding, each responsible for a specific operations.

Fig. 2 shows this arrangement.

 

ð  Suitability:- In this, similar equipment and similar machines are grouped together. This is very useful low volume of production is required.

ð  Advantages:-

(1)   Similar jobs are manufactured on similar machines, hence supervision is simple.

(2)   Minimum machines are required.

(3)   This offers great incentive for each worker to raise the level of performance.

(4)   There will better control on precision or complicated process.

(5)   The layout is flexible, hence it can easily be managed to change in the rate of production, in the design of products, in the methods of production or in the raw materials used.

(6)   Any breakdown of one machine does not affect production as it can be done on a standby machine.

(7)   Capital layout for machines is less.

(8)   New workers have better training facilities on the job.

(9)   Foremen become specialised in the performance of the job and know all about the equipment and their operations.

ð  Disadvantages:-

(1)   Handling and back-tracking of materials is too much.

(2)   It makes necessary to plan and supervisor the work of each department, each worker and machine. This makes production control more costly and difficult.

(3)   Generally floor area is required.

(4)   Specialisation creates monotony and there will be difficult for the workers to find job in other industries.

(5)   Total production cycle time is more due to long distance and waiting.

(6)   Routing and scheduling is more difficult, as the work does not flow through any definite mechanical channels.

(7)   There are no cheaper and automatic devices for internal transportation.

(8)   Inspection of work for each operation is necessary as the material passes to the next department.

(9)   More training will be required to prepare the workers for the jobs.

(C) Fixed Position Layout:-

ð  This type of layout is used in manufacturing huge aircrafts, ship and pressure vessels etc. where the product materials are too heavy.

ð  For such type of products, it is convenient and economical to bring the tools, machines and men etc. to the work place.

ð  This type of layout was very common before the industrial revolution but the present industries have grown much in size and complexity, therefore, now-a-days it is easy and more economical to move the materials to the equipment and machines.

ð  This type is also known as “static product Layout”.

Fig.3 shows a simple arrangement of this type of layout.

ð  Advantages:-

(1)   Capital investment is less.

(2)   Continuity of operations is ensured.

(3)   Less total production cost.

(4)   Less material movement.

ð  Disadvantages:-

(1)   Machines and tools etc. take more time to reach to the work place.

(2)   Highly skilled workers are required.

(3)   Complicated jigs and fixtures may be required in fixing jobs and tools etc.

(D)    Combination:-

ð  Now-a-days in pure state, any one form layout is very rarely found.

ð  Therefore, a combination of any of the three methods is formed according to the requirement of industry.

ð  In factories, where first the products are manufactured and then assembled this method is mostly used.

Flexibility of Plant Layout

ð  As far as possible certain amount of flexibility of arrangement and operation is essentially desired in plant layout.

ð  Economy should be the prime consideration in layout.

ð  When changes are affected in the product design, methods of operations, the type of the product or the production quantities then the machines or departments may also have to be rearranged.

ð  Therefore, it is necessary to design layouts in such a way so as to minimise the affect of subsequent alterations on the production process.

ð  Flexibility in layout can be secured in several ways.

(1)   Keep enough unobstructed floor areas.

(2)   Separate electric motors to be allowed on individual machines.

(3)   Mobile machinery should be used.

(4)   Equipment can be placed on rubber footings instead of being mounted permanently.

(5)   As far as possible small tools should be used.

(6)   Portable conveyor units may be used.

(7)   Overhead electrical lighting arrangements easily detachable can be used instead of permanent fittings.

(8)   Make use of portable jigs and fixtures.

Symptoms of a Bad Layout

ð  A poor or badly planned layout will generally show the following symptoms:-

(a)    Congestion of machines, materials, parts, assemblies and even workers.

(b)   Excessive amount of work in process.

(c)    Poor utilisation of available space.

(d)   Long material flow lines.

(e)    Some machines heavily loaded and some remain idle for long periods.

(f)    Excessive handling by skilled workers.

(g)   Long production cycles.

(h)   Delays in delivery.

(i)     Excessive mental or physical strain on workers.

(j)     Difficult to supervise and control properly.

Advantages of Scientific Layout

ð  A scientific layout has got the following important advantages:-

(a)    It reduces internal transport to a minimum.

(b)   It minimises accidents and makes supervision easy and quick.

(c)    It makes repairs and maintenance easy.

(d)   It yields higher profits. Therefore, higher wages can be paid to workers.

(e)    It reduces labour turn-over.

(f)    It reduces production delays to a large extent.

(g)   It keeps the shops neat and clean.

(h)   It minimises changes in the layout to a large extent every time.

(i)     It keeps control over production.

(j)     It eliminates waste effort and thus speed of production increases.

(k)   Back tracking is reduced.

(l)     Less capital is spent on machinery.

(m) It reduces wastage and spoiled work.

(n)   It reduces set up and total operation time.

(o)   Time and motion study can be easily and accurately performed.

(p)   Better utilisation of manpower.

(q)   Improvement in methods of production can be made.