The main advantage of continuous system is that work-in-progress inventory is minimum. As the processing of material is continuous and progressive, there is no waiting period. Each work is passed to the next stage immediately after the previous operation is complete without waiting for the completion of work on the total batch. As as result costs of materials handling are minimized and full use can be made of automation.
Different Types of Continuous Production System
Continuous or Flow Production System can be re-classified into:
a. Mass Production System
b. Process Production System
c. Assembly Production System
(a) Mass Production : Mass production refers to the manufacture of standardized parts or components on a large scale. Standardization of materials, machines, products and processes is the basic feature of mass production. The parts manufactured under mass production are combined in assembly line for making different products. Generally the degree of mechanization and automation is high. The mass production process is continuous.
Mass production system is employed in many industries where the production is carried on without Interruption. Electronics, electrical, automobiles, bicycles and container industries are a few examples of mass production industries. Mass production system offers economies of scale as the volume of output is large. Quality of products tends to be uniform and high due to standardization and mechanization. In a properly designed and equipped process, individual expertise plays a less prominent role. Of course the exact quality level depends upon the quality control systems and management policy of the plant.
(b) Process Production : Under this type of flow production, production is carried on continuously through a uniform and standardized sequence of operations. Highly sophisticated and automatic machines are used Process production is employed in bulk processing of certain materials. For example, crude oil is processed into petroleum, kerosene, diesel oil and gasoline. Similarly, sugarcane is processed into sugar and molasses. In the automobile industry, process production is used in making chassis. Chemicals, cement, etc. are other examples of process production industries. Plants employing process production system are known as ‘process plants’.
On the basis of the nature of production process, flow production may be classified into analytical and synthetic production. In analytical process of production, a raw material is broken into different products. For example, crude oil is analyzed into gas, naphtha, petrol, etc. Similarly, coal is processed to obtain coke, coal gas, ammonium liquor, coal-tar, etc.
Synthetic process of production, on the other hand, involves the mixing of two or more materials to manufacture a product. For instance, Lauric acid, Myristic acid, Plasmatic acid, Stearic acid, Linoleic acid, etc. are synthesized to manufacture soap.
(c) Assembly Lines : Assembly line is a type of now production which developed in the automobile industry in the U.S.A. A manufacturing unit prefers to develop and employ assembly line because it helps to improve the efficiency of production. The use of flow production methods results in cost reduction. Assembly line is particularly useful when a limited variety of similar products is to be produced on a mass scale or in fairly large batches on a regular or continuous basis. In any production system the most vital decision is the proper layout of assembly line. The design of assembly line involves the proper balancing of technology and other manufacturing facilities so. as to develop a rational approach for optimization of results. The assembly line design depends largely upon product design and location of production.
In order to develop an assembly line machines are positioned keeping in view the following considerations :
(i) the rate of flow of work
(ii) the direction of manufacturing operations
(iii) the convenience and comfort of operators or workers
(iv) the availability of service facilities like water, electricity, compressed air, oxygen, etc.
(v) the supply and demand of materials.
In an assembly line, each machine must directly receive material from the previous machine and pass it on directly to the next machine. Therefore, the location of machines is automatically regulated by the sequence of operations. Machines and equipment should be arranged in such a manner that every operator has a free and safe access to each machine.
Space should be provided for free movement of fork lifts, etc. which deliver materials and collect finished products. The passage should not be blocked and workers must not be in danger of being hit by the moving trollies, etc. At the same time there should be economical utilization of floor space. These days assembly line process is employed in assembling automobiles, radios, televisions, computers, videos and other electrical and electronic products.