PPC (production planning and control) under different production systems: Process, Job, Intermittent, and Assembly Production Industry…No single system of production planning and control is good for all types of industries. The nature of PPC varies from firm to firm depending upon the type of production process. In the manufacturing industry, raw materials are covered into components, semi-finished products, and finished products. But some firms are engaged in the assembling of products. An assembling industry combines several components or parts to make the finished product, e.g. bicycle, typewriter, fan, scooter, etc.
The application of production planning and control to various types of products has been explained below:
PPC in Process Production Industry:
Production planning and control in the process industry are relatively simple. Routing is almost automatic and uniform because standardized techniques and specialized equipment are used in production processes. The product is standardized and goods are produced for stock. Therefore, scheduling is easy and department schedules can be prepared from the master schedule continuingly.
Dispatching involves repetitive orders issued to ensure a steady flow of materials through the plant. In the process industry, decentralized dispatching can be used so that each foreman can issue orders and instructions to each operator and machine under his charge as per the circumstances of his work-station.
The sequence of operations being uniform, responsibility for quality control can be delegated to individual production units to ensure that the products manufactured conform to the specifications laid down in advance. Thus, the main task of production planning and control in the process industry is the maintain a continuous and uniform flow of work at the predetermined rate so that there is full utilization of plant capacity and the work is completed in time. Therefore, it is known as “flow control”.
PPC in Job Production Industry:
Production planning and control are relatively difficult in the job production industry. Every order is of a different type and it entails a particular sequence of operations. There is not a standardized route plan and a new route has to be prepared for every order. Specific orders are assigned to different workstations according to the capacities available with them.
Production, schedules are drawn up according to relative urgency of the order. An order received later may have to be supplied earlier. Sometimes, it may not be possible to schedule all operations relating to order simultaneously. Dispatching and follow up are also order-oriented. For every order fresh instructions and follow up measures have to be undertaken. Therefore, production control is job production system may be called “Order control”.
PPC in Intermittent Production Industry:
In the case of intermittent production, raw materials are converted into components or parts for stock but they are combined according to the customer’s orders. The products are manufactured usually in large batches. Every batch differs from others but all units within a batch are identical. Several heterogeneous finished products are manufactured within a limited range of options.
Therefore, production planning and control in intermittent manufacturing is a mixture of those used in the process industry and job order production. There is a standardized component and production schedules are continuous. But the routes and schedules for intermediate operations have to be changed every time. To avoid delays and bottlenecks in the production process, great care needs to be taken in dispatching.
Before issuing orders and instructions need for new materials and tools, overloading and underloading of particular machines/operators and other problems must be anticipated. As the product is diversified and several orders are being handled simultaneously in different work-centers, follow up is a cumbersome task in intermittent manufacturing. Follow up may be organized either according to product or process. Follow up by-product is suitable for process or continuous production system.
It is relatively simple because there is an automatic flow of work from one operation to another and the follow-up mart has simply to report and remove breakdown, delays, shortage of materials and tools that obstruct the smooth flow of production. But in the intermittent production system, follow up by process is used. In every department, the follow-up men check the progress of work passing through that department. The follow-up men do not require knowledge and information about all the departments.
But they have to be more alert as the flow of work from one operation to another is not automatic. Quality has to be controlled both during the manufacture of components and during their conversion into the finished product. In practice, a combination of flow and order controls known as block control may be used. Flow control is employed to produce standardized components and order control is used for the manufacture of finished products.
PPC in Assembly Production Industry:
In an assembly industry, there is a uniform sequence of repetitive operations but the number of components and their proportion to be assembled differ from one product to another. Once the sequence of operations has been decided, the efficiency depends upon the regular and timely supply of the required components.
The entire production line may be held up and machinery and men may remain idle on account of the non-availability of one single component at the proper time and in the required quantity. It is, therefore, essential to determine first of all the type and quantity of various components required at different stages in the assembling of a product. This will depend upon the nature and volume of a product to be assembled during a particular period.
Production schedules are drawn up for each product to achieve the targets of production. Assembly work for different products is assigned to various machines and operators according to their capacities and suitability. Instructions are issued in such a manner that the responsibility, for a particular product is fixed on specific employees. Follow up measures need to be taken to ensure that every product is being assembled as per the specifications and schedules laid down in advance.