About Plant Layout

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Plant layout refers to an arrangement of all factors of production or inputs required for producing or providing services efficiently. Plant layout not only makes the initial layout of machines and other facilities but also encompasses improvement in the existing layout. Plant layout can be accordingly defined as, “a floor plan for determining arranging the desired machinery and equipment of a plant to permit the quickest flow of material at the lowest cost and with the least amount of handling in processing the product from the receipt of the raw materials to the shipment of the finished products.”[1]

The definition highlights key features of a plant layout, which are listed below[2]:

  1. To use workers and space efficiently
  2. To minimize material handling costs
  3. To eliminate unnecessary movements of workers or materials
  4. To minimize production time and customer service time and eliminating delays
  5. To design for safety of workers and the plant and providing good and improved working conditions
  6. To facilitate attainment of product or service quality

Types of Plant Layout

There are five types of plant layout: – Process layout, Product Layout, Fixed Position Layout, Cellular Manufacturing and combined layout

1. Process Layout: It involves grouping the same kinds of machines in one department. For example, machines performing drilling operations are arranged in drilling department. Process layout is also known as functional layout and evolved from handicraft method of production. For example, an office containing different departments for finance and accounts, human resources and payroll, administration, library, housekeeping, library, etc. Process layouts in an organisation can be practised based on the following principles as follows:

a. The distance between departments should be as short as possible to avoid long-distance movements of materials

b. The departments should be in sequence of operations

c. There should exist convenience for inspection and supervision

Process layout has advantages that are listed below:

1)      Flexibility[3]: An organisation has the ability to handle a variety of processing requirements and enables flexibility in allocating personnel and equipment because general purpose machines are used

2)      Cost: General purpose machines utilised are mostly less inexpensive as well as less costly and easier to maintain that specialised equipment

3)      System Protection: As there are multiple machines (in one department), such layouts are not particularly vulnerable to equipment failures or breakdowns, shortages, or absenteeism.

4)      Economies of scale[4]: Process layout is designed to increase economies of scale by allowing individual processes to function more efficiently by allocating relevant resources. Process layouts are accordingly considered to be ideal for businesses that produce large volumes of product each day. For example, businesses in textile industry, pharmaceutical industry, etc.

5)      Incentives for workers: Workers can easily specialise in specific work process and learn from colleagues performing same jobs. Accordingly, tasks available for workers are also varied within the same business unit.

Process layout also has disadvantages that are listed below:

1)      Utilisation: Equipment utilisation rates are low especially during slowdown. The layout is useful with bulk orders and do not full capacities for individual or smaller orders. Accordingly, costs incurred for smaller orders are very high

2)      Excess material handling: With less bulk orders in demand, handing underutilised materials become costly. Accordingly, inventory control costs are also high

3)      Difficulties in operations control[5]: Constantly changing schedules and routings during possible alterations gets very confusing and difficult

 

2. Product Layout: Product layout is also known as a straight-line layout. It involves the arrangement or sequence of interconnected work stations of different machines in one line. Work is done in small amounts at each work station in the sequence leading to higher rates of production. Accordingly, the sequence begins with raw materials put in one work station, followed by its processing in one or multiple work stations and final product produced at a work station at the end of the sequence. Each work station would be interconnected by either conveyors belts or transferred manually by workers. Testing, final inspection and packing could also be a part of the layout. For example, assembly lines in automobiles. Product layouts in an organisation can be practised based on the following principles as follows:

  1. An adequate or specific volume to be manufactured/provided for possible reasonable use of equipment in work stations
  2. Stable product demand
  3. Product standardisation
  4. Continuous material supply

Product layout has advantages that are listed below:

1)      Production control is simple because product designs are stable and the processes are standardised

2)      Space requirements are also smaller than required under process layout because the arrangement of work stations is done to manufacture a specific volume or units of product

3)      Cost of material handling is optimum as the flow of the material is known prior to transformation into a standardised product. This process also makes the flow of material smooth and continuous

4)      Product cycle time is less because possibility of congestion is low and waiting time in a machine is also low

5)      Requirement of skilled workers is minimal especially when workers are expected to do specific tasks in the standardised set-up. Unskilled workers can also be easily trained

6)      Overall cost of production per unit is low

Product layout has disadvantages that are listed below:

1)      Jobs or tasks in the sequence of activities could be dull and repetitive jobs could get stressful. Also, such layouts make it difficult to administer individual incentive plans

2)      Product variety is very limited and changes in product design also cannot be accommodated

3)      Any possible breakdown could halt the production process

4)      Duplication of machines in the sequence may be needed and may lead to high capital investments

5)      The flexibility to increase production capacities is limited

 

3. Fixed Position Layout: Also, known as project layout, the equipment, heavy materials, sub-assemblies, etc, all remain fixed at one place and the job is completed by movement of machines, workers and tools to the location of the operations. For example, ship building projects, aerospace, etc.

Fixed Position layout has advantages that are listed below:

1)      Easy for products that are difficult to move

2)      Flexibility for change in design, operation sequence, labour availability, etc., exists in this layout

3)      This layout can be cost-effective when many orders of similar type are existing in different stages of progress

4)      Large project type of jobs such as construction are suited in this layout

Fixed Position layout has disadvantages that are listed below:

1)      High capital investments due to long durations to complete a product

2)      Space requirement for storage of material and equipment is large

3)      It requires careful project planning and focussed attention on critical activities otherwise confusion, delay and conflict may arise

 

4. Cellular Layout: This is also known as group layout, which is suitable for manufacturing large variety of products in small volumes or batches. It is based on the Group Technology (GT) principle that involves identifying parts with similar design characteristics (like size, shape ad function) and similar process characteristics (type of processing required, available machinery that performs a particular process, etc)[7]. Cellular layout is thus known to be a combination of process and product layout. Workers in cellular technology can be cross-trained so that they can operate all equipment within the cell and take responsibility for the output.

Cellular layout has advantages that are listed below:

1)      The layout allows production of small batches further providing increased flexibility

2)      Machine utilisation is higher than the other layouts

3)      It provides faster processing time, less material handling, less work-in-process inventory and reduced set-up time which in turn reduce overall costs of production

4)      As workers are cross-trained to run almost every machine, boredom is less of a factor leading to worker empowerment and autonomy

Cellular layout has disadvantages that are listed below:

1)      Greater labour skills required

2)      Balance in flow of overall activities is required in each cell

3)      Some disadvantages of process and product layouts are faced in cellular layout (Identity which?)

 

5. Combination Layout: Also known as hybrid layout, a mixture of three main layouts can be combination layout. For example, one firm may utilize a process layout for the majority of its process along with an assembly in one area. Alternatively, a firm may utilize a fixed-position layout for the assembly of its final product, but use assembly lines to produce the components and subassemblies that make up the final product