Unit 2: factory layout

Layout is the arrangement of work space, equipment, products, rooms, doors, passageways, and so on in a place of business. In a well planned factory layout everything is arranged so that the product and workers move in an orderly manner and with the least possible confusion. Proper arrangement is necessary for smooth operation of the production system, the elimination of bottlenecks, and the minimum buildup of inventories and semi-finished products. A good layout should also take the worker into account so that there is a favorable working environment. An efficient layout helps to increase worker productivity and keep costs down by reducing walking distances for employees and keeping supervisors and maintenance personnel close to their areas of responsibility.

When planning a layout, the workers, the types of product and the method of production, and the cost of space are all items which should be considered. It is much better to take the time to plan a good layout in the beginning than to have to change a poor one later. Plants and buildings cost a lot of money, and the cost is usually based on the amount of space involved. Efficient use of space is necessary in order to keep costs down. The modern practice, therefore, is to design the layout before the buildings are constructed. The buildings can then be designed to suit the layout. This is much more efficient than trying to design a layout to suit buildings already built.

Two general types of factory layout are associated with two basic methods of production. The continuous production method, which is used for petroleum, chemicals, and massed produced items such as automobiles and appliances, uses what is called a product layout. Intermittent production, used for example in a furniture factory and general machines shops where there are several different products and jobs, employs a process of functional layout.

With product layout the factory is set up to suit the particular product being manufactured. Employees and machines perform their operations on the product as it moves along an assembly line from start to finish. There are both advantages and disadvantages to this type of layout.

One advantage of product layout is that the use of assembly line usually has lower unit costs than other methods have. The unit cost is the cost for producing one individual item. This lower unit cost can be a result of a combination of factors. Machines and assembly lines can move the product through the production process quickly and efficiently. Raw materials are consumed at fixed rates that are easily controlled. This makes large inventories and storage unnecessary. Another advantage is that by controlling and coordinating the use of machines, scheduling and routing are simplified so that the bottlenecks are eliminated. Furthermore, finished products roll of the assembly line at one point where they can be easily and quickly stacked, palletized, loaded onto trucks and shipped. Finally, control and supervision are simplified by using product layout since each worker has a specific assignment on the line.

A disadvantage of this type of layout is that a breakdown at any point on the assembly line usually results in a total shutdown of the line. Also specialized machinery which is not easily adapted for other uses and uniform interchangeable parts are usually required for product layout. The result is that there are not many design changes or improvements which can be made to a product once production has started. Changes can be added only once a year when retooling is made for the new models. A high volume is necessary to insure low unit costs, but the rate of production can be increased only by purchasing additional production equipment or by adding a second shift of workers. Finally employee morale and workmanship can suffer because assembly line work is generally routine and boring. It is difficult for a worker to take personal pride in a massed produced product, and this alienation can result in a lack of job satisfaction.

Intermittent production employs a process or functional layout. In this type of layout, machines, materials, and workers are grouped according to the particular process each performs. In a furniture factory, for example, the cutting, gluing, and finishing or painting would all be done in different areas using different tools. In a machine shop, the grinding, sawing, drilling, and turning would be done in different areas on the appropriate machines. This type of layout also has advantages and disadvantages.

An advantage of process layout is that there is flexibility in the types of products manufactured, the duties of workers, and the uses of machines. General purpose machines can be used for process layout, and these machines are usually less expensive and do not become obsolete as quickly as specialized assembly line machinery does. Machines operate independently of each other, and a breakdown of one machine would not result in a total line shutdown and, therefore, a complete halt in production. Different jobs are done in different areas; in this way interference is reduced. Furniture finishing, for example, must be done in a dust-free environment away from the saws and sanders. An advantage for workers is that they each have a specific job which they can call their own and take pride in.

A disadvantage of process layout is that there is no definite line in which materials move; therefore, they tend to move less efficiently. Special routing and cost analysis are necessary for each job order. Flexibility of product demands that there be a larger inventory of raw materials, since the amount of specific materials for each product or job order may vary. Generally, there is slower productivity with process layout, and production volume is restricted. If demand for a product increases substantially, it is often more efficient to change to product layout for a specific product.

Дата добавления: 2015-11-14