Why CAD/CAM

Computer-aided design (CAD) and computer-aided manufacturing (CAM) is a pair of often interdependent industrial computer applications that have greatly influenced the chain of processes between the initial design and the final realization of a product. Many would add to this duo a third technology, computer-aided engineering (CAE). Ongoing refinements in CAD/CAM systems continue to save manufacturers tens of millions of dollars in time and resources over non-computerized methods. As a consequence, CAD and CAM technologies are responsible for massive gains in both productivity and quality, particularly since the 1980s. For some purposes CAD and CAM methods can be used exclusively of one another, and in general, CAD is used more commonly than CAM.

CAD involves creating computer models defined by geometrical parameters. These models typically appear on a computer monitor as a three-dimensional representation of a part or a system of parts, which can be readily altered by changing relevant parameters. CAD systems enable designers to view objects under a wide variety of representations and to test these objects by simulating real-world conditions.

CAM picks up where CAD leaves off by using 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 is encoded mechanically. Since both CAD and CAM use computer-based methods for encoding geometrical data, it is possible for the processes of design and manufacture to be highly integrated.

Using CAD it is possible to simulate in three dimensions the movement of a part through a production process. This process can simulate feed rates, angles and speeds of machine tools, the position of part-holding clamps, as well as range and other constraints limiting the operations of a machine. The continuing development of the simulation of various manufacturing processes is one of the key means by which CAD and CAM systems are becoming more tightly integrated. CAD/CAM systems also facilitate communication among those involved in design, manufacturing, and other processes. This is of particular importance when one firm contracts another to either design or produce a component. Many CAD/CAM software tools are highly specialized, and thus a multi stage manufacturing process, such as is used for complex products like motor vehicles, airplanes, and ships, requires more than one CAD program to design and integrate the various parts. For example, in ship design manufacturers may use one CAD application for designing the vessel's steel structure and another for designing the propeller assembly. Such specialization ensures that designers have adequate layout and specification tools in the software to work with.

CAD has been applied to many industrial sectors. n The mechanical sector is the largest user of CAD systems. Applications are usually coupled with manufacturing, forming a CAD/CAM system. The applications cover all types of manufacturing operations, such as milling (2 , 3 5 axis of control), turning, wire EDM, punching, etc. The user can test the part programme on screen prior to the transfer to the machine tool and accomplish collision detection, undercuts, etc. Most of the systems have a post processor integrated to communicate with the machine tools.

The AEC sector is the second largest application areas of CAD systems. Applications range from single a simple building design, to large scale projects, interior design, static and dynamic analysis, etc. These applications are beyond the scope of this report.

The electronics engineering is the third largest application. The computer performs all IC designs. It is the complexity of the designs that imposes the usage of CAD systems. Current systems also include in their software a number of designs in order to offer some assistance to the users for their new designs. The apparel industry is also a large user. The number of systems on offer is limited. A small number of companies are offering systems for the apparel sector worldwide, while on a national base there is a number of companies offering such systems. Systems for clothing are rather expensive, because they are using specialised equipment, such as large plotters, cutters for patterns, and automatic machines for cutting the fabric. Their application ranges from fashion design to manufacturing. The largest usage of the systems is for pattern design and lay planning, where most of the savings are achieved. It is absolutely necessary today for all companies subcontracting a large supplier to be able to handle electronic data (pattern designs). Lay planning can save on material and it can justify the investment in CAD. Today the application of fashion design systems is becoming quite popular. These systems can produce a whole collection on paper, saving a lot of money on sampling and quite often are connected to special ink-jet printers capable of printing on fabric for quick sampling. Similar to the CNC machines used in metal manufacturing, computer controlled machines exist in the apparel industry. These machines perform fabric laying and cutting automatically and they are controlled directly from the CAD systems. In addition, they can be combined with storage system in front of them forming a kind of Flexible Manufacturing Cell.