Manufacturing Strategy
Manufacturing processes can be conveniently broken down into 3 categories:
- Flow manufacturing,
- Intermittent manufacturing,
- Project manufacturing.
Flow manufacturing. It is concerned with the production of high-volume standard products. If the units are discrete (e.g., cars), the process is usually called repetitive manufacturing and if the goods are made in a continuous flow (e.g., gasoline), continuous manufacturing. There are 4 major characteristics to flow manufacturing:
- Routings are fixed and work centers are arranged according to the routing.
- The time taken to perform work at one work center is almost the same as any other work center in the line;
- Work centers are dedicated to producing a limited range of similar products. Machinery and tooling are especially designed to make the specific products;
- Material flows from one workstation to another using some form of mechanical transfer. There is little buildup in work-in-process inventory and throughput times are low;
- Capacity is fixed by the line.
PAC concentrates on planning the flow of work and making sure that the right material is fed to the line as stated in the planned-schedule. Since work flows from one workstation to another automatically, implementation and control are relatively simple.
Intermittent manufacturing It is characterized by many variations in product design, process requirements and order quantities.
If a small business is going to manufacturer products that are of a similar type, they can adopt an intermittent manufacturing method. Businesses that manufacturer items that are similar in nature, but have variations, are suitable for intermittent manufacturing. For example a company that only manufacturers tires for bicycles will sell tires that are of different sizes to fit a variety of bicycle wheels. Businesses will manufacture batches of the same product depending on demand and then will manufacture a batch of the same or another product. This type of manufacturing is good for products, which are based on fluctuating demand.
This kind of manufacturing ischaracterized by the following:
- Flow of work through the shop is varied and depends on the design of a particular product. As orders are processed, they will take more time at one workstation than an another. The work flow is not balanced;
- Machinery and workers must be flexible enough to do the variety of work. Machinery and work centers are usually grouped according to the function they perform (e.g., all lathes in one department);
- Throughput times are generally long. Scheduling work to arrive just when needed is difficult, the time, taken by an order at each work center and
work queues, varies causing long delays in processing. Work-in-process Inventory is often large;
- The capacity required depends on the particular mix of products being built and is difficult to predict.
PAC in intermittent manufacturing is complex. Planning and control are typically exercised using shop orders for each batch being produced.
Project manufacturing. It usually involves the creation of one or a small number of units (e.g., large shipbuilding). Because the design of a product is often carried out or modified as the project develops, there is close coordination between manufacturing, marketing, purchasing and engineering.