Outline of Contents:
What is Plant layout?
Necessity of good layout
Factors affecting good layout
Principles of good layout
Advantages of good layout
Symptoms of poor layout
Types of layout
What is PLANT LAYOUT?
Plant layout refers to the arrangement of physical facilities such as machines, equipment, tools, furniture etc. in such a manner so as to have quickest flow of material at the lowest cost and with the least amount of handling in processing the product from the receipt of raw material to the delivery of the final product. Plant Layout is a plan of an optimum arrangement of facilities including personnel, operating equipment, storage space, material handling equipments and all other supporting services along with the design of best structure to contain all these facilities. A good layout is one which allows material rapidly and directly for processing. This reduces transport handling, clerical and other costs down per unit. Space requirement are minimized and it reduces idle machine time and idle time of man.
Necessity of good plant layout
Minimization of material handling
Optimum utilization of available floor space
Elimination of bottlenecks through balancing of all capacities
Minimization o production delays
Easy supervision and better manpower resources through elimination of idle time
Elimination of physical efforts required by workers
Elimination or improvement of objectionable operations. E.g. Operations with bad odor, vibrating operations etc.
Avoiding industrial accidents
Better working conditions like light, ventilation, noise control etc. Optimum utilization of machinery and equipment through proper use.
Minimization of cost so that product will be available at cheaper rate to customer and delivery in time.
Factors affecting facility Layout
Nature of plant-Engineering/Process Industry
Type of Production-Mass/Flow, Batch, Job Shop
Type of Production-Make to Stock/order, std/spec
Plant Location-Area available, building type-storey
Volume of Production-Scale of production
Types of machines and equipment-automation
Repairs and maintenance -Policy, schedule on site
Arrangement of material handling equipment
Future expansion plan
Principles of good Layout
Integration of factors-3M
Optimum utilization of available space
Safety, Security and Satisfaction
Advantages of Good Plant Layout
Proper and efficient utilization of available floor space
Transportation of work from one point to another point without any delay Proper utilization of production capacity.
Reduce material handling costs
Utilize labor efficiently
Provide for volume and product flexibility
Provide ease of supervision and control
Provide for employee safety and health
Allow easy maintenance of machines and plant.
Symptoms of Poor Layout
Delays and work stoppage in manufacturing process
Slow movement of material through the plant
Congestion of materials, components and work in progress
Poor utilization of space
High material handling and transportation costs
Excessive handling by skilled workers
Production cycles and delays in delivery
Mental or physical strain on operators
Difficulties in maintain effective supervision and control
Underutilization of machines and workers
Lack of flexibility and difficulty in production planning and control
Types Of Layout:
There are mainly four types of plant layout:
(a) Product or line layout
(b) Process or functional layout
(c) Fixed position or location layout
(d) Combined or group layout
Product or line layout:
In this type of layout the machines and equipments are arranged in one line depending upon the sequence of operations required for the product. It is also called as line layout. The material moves to another machine sequentially without any backtracking or deviation i.e. the output of one machine becomes input of the next machine. It requires a very little material handling. It is used for mass production of standardized products.
Advantages of Product layout:
Low cost of material handling, due to straight and short route and absence of
backtracking Smooth and continuous operations
Continuous flow of work
Lesser inventory and work in progress
Optimum use of floor space
Simple and effective inspection of work and simplified production control
Lower manufacturing cost per unit
Disadvantages of Product layout:
Higher initial capital investment in special purpose machine (SPM) High overhead charges
Breakdown of one machine will disturb the production process.
Lesser flexibility of physical resources.
In this type of layout the machines of a similar type are arranged together at one place. This type of layout is used for batch production. It is preferred when the product is not standardized and the quantity produced is very small.
Advantages of Process layout
Lower initial capital investment is required.
There is high degree of machine utilization, as a machine is not blocked for a single product
The overhead costs are relatively low
Breakdown of one machine does not disturb the production process. Supervision can be more effective and specialized.
Greater flexibility of resources.
Disadvantages of Process layout:
Material handling costs are high due to backtracking
More skilled labour is required resulting in higher cost.
Work in progress inventory is high needing greater storage space More frequent inspection is needed which results in costly supervision Combined layout:
A combination of process & product layout is known as combined layout. Manufacturing concerns where several products are produced in repeated numbers with no likelihood of continuous production, combined layout is
followed Fixed position or location layout:
Fixed position layout involves the movement of manpower and machines to the product which remains stationary. The movement of men and machines is advisable as the cost of moving them would be lesser. This type of layout is preferred where the size of the job is bulky and heavy. Example of such type of layout is locomotives, ships, boilers, generators, wagon building, aircraft manufacturing, etc.
Advantages of Fixed position layout:
The investment on layout is very small. The layout is flexible as change in job design and operation sequence can be easily incorporated. Adjustments can be made to meet shortage of materials or absence of workers by changing the sequence of operations.
Disadvantages of Fixed position layout:
As the production period being very long so the capital investment is very high. Very large space is required for storage of material and equipment near the product. As several operations are often carried out simultaneously so there is possibility of confusion and conflicts among different workgroups.
Keeping in view the type of industry and volume of production, the type of layout to be selected is to be decided from the following:
1. Product or Line Layout
2. Process or Functional Layout.
3. Fixed Position Layout.
4. Combination type of Layout.
1. Product or Line Layout:
If all the processing equipment and machines are arranged according to the sequence of operations of the product, the layout is called product type of layout. In this type of layout, only one product of one type of products is produced in an operating area. This product must be standardized and produced in large quantities in order to justify the product layout.
The raw material is supplied at one end of the line and goes from one operation to the next quite rapidly with a minimum work in process, storage and material handling. Fig. 8.3 shows product layout for two types of products A and B.
Advantages offered by Product Layout:
(i) Lowers total material handling cost.
(ii) There is less work in processes.
(iii) Better utilization of men and machines,
(iv) Less floor area is occupied by material in transit and for temporary storages.
(v) Greater simplicity of production control.
(vi) Total production time is also minimized.
Limitations of Product Layout:
(i) No flexibility which is generally required is obtained in this layout.
(ii) The manufacturing cost increases with a fall in volume of production.
(iii) If one or two lines are running light, there is a considerable machine idleness.
(iv) A single machine break down may shut down the whole production line.
(v) Specialized and strict supervision is essential.
2. Process or Functional Layout:
The process layout is particularly useful where low volume of production is needed. If the products are not standardized, the process layout is more low desirable, because it has creator process flexibility than other. In this type of layout, the machines and not arranged according to the sequence of operations but are arranged according to the nature or type of the operations. This layout is commonly suitable for non repetitive jobs.
Same type of operation facilities are grouped together such as lathes will be placed at one place, all the drill machines are at another place and so on. See Fig. 8.4 for process layout. Therefore, the process carried out in that area is according to the machine available in that area.
Advantages of Process Layout:
(i) There will be less duplication of machines. Thus, total investment in equipment purchase will be reduced.
(ii) It offers better and more efficient supervision through specialization at various levels.
(iii) There is a greater flexibility in equipment and man power thus load distribution is easily controlled.
(iv) Better utilization of equipment available is possible.
(v) Break down of equipment can be easily handled by transferring work to another machine/work station.
(vi) There will be better control of complicated or precision processes, especially where much inspection is required.
Limitations of Process Layout:
(i) There are long material flow lines and hence the expensive handling is required.
(ii) Total production cycle time is more owing to long distances and waiting at various points.
(iii) Since more work is in queue and waiting for further operation hence bottle necks occur.
(iv) Generally, more floor area is required.
(v) Since work does not flow through definite lines, counting and scheduling is more tedious.
(vi) Specialization creates monotony and there will be difficult for the laid workers to find job in other industries.
3. Fixed Position Layout:
This type of layout is the least important for today’s manufacturing industries. In this type of layout the major component remain in a fixed location, other materials, parts, tools, machinery, man power and other supporting equipment’s are brought to this location.
The major component or body of the product remain in a fixed position because it is too heavy or too big and as such it is economical and convenient to bring the necessary tools and equipment’s to work place along with the man power. This type of layout is used in the manufacture of boilers, hydraulic and steam turbines and ships etc.
Advantages Offered by Fixed Position Layout:
(i) Material movement is reduced
(ii) Capital investment is minimized.
(iii) The task is usually done by gang of operators, hence continuity of operations is ensured
(iv) Production centers are independent of each other. Hence, effective planning and loading can be made. Thus total production cost will be reduced.
(v) It offers greater flexibility and allows change in product design, product mix and production volume.
Limitations of Fixed Position Layout:
(i) Highly skilled man power is required.
(ii) Movement of machines equipment’s to production centre may be time consuming.
(iii) Complicated fixtures may be required for positioning of jobs and tools. This may increase the cost of production.
4. Combination Type of Layout:
Now a days in pure state any one form of layouts discussed above is rarely found. Therefore, generally the layouts used in industries are the compromise of the above mentioned layouts. Every layout has got certain advantages and limitations. Therefore, industries would to like use any type of layout as such.
Flexibility is a very important factory, so layout should be such which can be molded according to the requirements of industry, without much investment. If the good features of all types of layouts are connected, a compromise solution can be obtained which will be more economical and flexible.