CONTINUOUS FLOW PROCESSES
In continuous manufacturing, the production of the standard products is carried on a flow basis at a predetermined rate. The mass production is carried on continuously for stock in anticipation of demand. Due to the production of the standardized products, the product design tends to be constant. The number of operations and the sequence of operations remain more or less same.
Continuous manufacturing is most suitable to process industries such as the chemical industry, refineries, food processing etc., and can also be applied to assembling industries such as automobiles, radios, refrigerators, typewriters, switchgear and similar products.
The machines are arranged on the basis of product layout, i.e. they are arranged in the sequence according to the operation sequence of the product. The material handling and positioning is mechanized mostly on the conveyor lines. The machines set-up remains unchanged for a longer-time. Generally, the machines performing specific operations are used and are operated by semi-skilled operators.
The line-balancing is made by providing more machines performing production which is time synchronized. The entire production line is characterized by fixed rated capacity. Like intermittent production, the possibilities of waiting or rushing do not exist in continuous production.
Though the production is made on continuous basis, the operating cycle time i.e. time required to convert the raw materials into finished products, is relatively short. In the continuous assembling production, a constantly moving conveyor is employed. The base frame of the product starts from the first stage of the line and other component parts or sub-assemblies are added at subsequent stages of the line as the product moves. Thus, it grows on the line and is taken off at the final stage of the line.
The investments in the inventories are relatively less as compared to intermittent production. This production system requires the standard materials and their requirements can be estimated reliably on the basis of the production schedule. It does not necessitate the sub-storing and reservoir of materials as required in case of intermittent production. In assembling industry, sometimes the components are manufactured in advance of production (for assembly line) and are kept as reservoirs. In fact, they serve as raw materials, which are fed to the assembly line. In the continuous production, usually the production of, a few standardized products are made on the large scale for stock. However, sometimes the continuous production is also made according to the customerâ€™s order, provided it is of a fairly large size and is in consistency with the product line e.g. production of monopoly design of some customer in the textile industry, production of standardized engineering parts on a large scale, say, 1,00,000 pieces etc. In such a situation, jobbing is nearer to continuous production.
The problems of production planning and control are relatively simplified as compared to intermittent production. The production schedule is based o the adjusted demand forecasting. The entire production activity is geared up to the production schedule.
The routing is simple due to the standard operations, preset sequence of operations and automated material handling. The preparation of the route sheets and the duties of the route clerk are routine and mechanical. The scheduling function is also simple due to the synchronization of the operations. The periodic production is made according to the master schedule.
Some adjustments in the production schedule would be necessitated on the basis of the fluctuations in demand and the stockpiling of the finished product. In the assembling industry, where the parts and components are fabricated in the unit itself, proper scheduling would be required for the fabrication of such parts and components well in advance. Scheduling would also face a specific problem in case of interruption in production flow caused by machine breakdown, power cut, material shortage, labor trouble etc.
Dispatching function stands to be easy due to standard machine set-up, standing instructions to the operators and use of standard material and tools. The follow-up function does not see any special problem unless there are some interruptions in the production flow. The main task of the follow-up function is to see that the continuity of the flow is maintained. For the effective follow-up, stand by equipments are maintained for strategic operations and the reservoirs of the key material or parts are maintained. Sufficient attention is given to the quality of production, rate of rejections, oiling, cleaning, repairing and maintenance of machines and equipment.
The products manufactured from this method are standardized with acceptable quality standards like ISO or IS and marketed with the same design as intended by the manufacturer. Except for very large quantity with product synergy this method does not involve custom made products.