The third source of CAD development resulted from efforts to facilitate the flow from the design process to the manufacturing process using numerical control (NC) technologies, which enjoyed widespread use in many applications by the mid-1960s.It was this source that resulted in the linkage between CAD and CAM.One of the most important trends in CAD/CAM technologies is the ever-tighter integration between the design and manufacturing stages of CAD/CAM-based production processes.The development of CAD and CAM and particularly the linkage between the two overcame traditional NC shortcomings in expense, ease of use, and speed by enabling the design and manufacture of a part to be undertaken using the same system of encoding geometrical data.CAD systems also offer "zoom" features analogous to a camera lens, whereby a designer can magnify certain elements of a model to facilitate inspection.Computer models are typically three dimensional and can be rotated on any axis, much as one could rotate an actual three dimensional model in one's hand, enabling the designer to gain a fuller sense of the object.The rapid growth in the use of CAD/CAM technologies after the early 1970s was made possible by the development of mass-produced silicon chips and the microprocessor, resulting in more readily affordable computers.
The first source of CAD resulted from attempts to automate the drafting process.
CAD systems enable designers to view objects under a wide variety of representations and to test these objects by simulating real-world conditions.
Computer-aided manufacturing (CAM) uses geometrical design data to control automated machinery.
CAM systems are associated with computer numerical control (CNC) or direct numerical control (DNC) systems.
These systems differ from older forms of numerical control (NC) in that geometrical data are encoded mechanically.