All the engineering functions in design and manufacturing are included in CAD/CAM. Engineering activities in design include product design, engineering analysis and drafting whereas the process planning and NC part programming come in the manufacturing functions. The literal meaning of CAM is the manufacturing of the products with the aid of computers.

Conventional methods are replaced by CAD/CAM. The direct link between product design and manufacturing is established with the help of CAD/CAM. While considering ideal CAD/CAM system, it takes the specific design of the product because it remains in the database and is converted into a process plan for manufacturing a product. CAD/CAM system automatically converts design of a product into a process plan. On a numerically controlled machine tool, a large portion of the processing can be completed. CAD/CAM automatically generates NC part programming. Using telecommunication network, NC program is directly downloaded to the machine tool in CAD/CAM system. Thus under CAD/CAM system, computer implements all the functions such as Product design, NC programming and Physical Production.

CIM sums up all of the manufacturing functions of CAD/CAM along with firm’s business functions which are related to manufacturing. CIM system includes the application of computer and communication technologies to all of the operational functions and information processing functions starting from the order receipt through design and production to product delivery. Figure 1 depicts the scope of CIM and its comparison with the limited scope of CAD/CAM.

The main aim of the CIM is to incorporate the firm’s operations related to production in an integrated computer system to assist, augment, and automate the operations.

Computer system touches all the activities throughout the firm that support manufacturing. In CIM, the output of one’s activities act as input to the other activity and it starts with the sales order and finishes with its delivery. The components of the integrated computer system are illustrated in Figure 2. Initially, customer’s orders that contain the specifications describing the product are entered by either the company’s sales force or directly by the customer into a computerized order entry system. Product design department takes these specifications as the input. Manufacturing engineering takes its input from the output of the design department where process planning, tool design, and similar activities are supported by the CIM system. CAPP performs process planning. On a CAD system, using the product model which is generated during product design, tool and fixture design is done. Manufacturing engineering provides its output into production planning and control, where material requirements planning and scheduling are performed using the computer system.