1、1 Computer-aided Design and Computer-aided Manufacturing(CADCAM) Throughout the history of our industrial society， many invention have been patented and whole new technologies have evolved .Whitney is concept of interchangeable parts， Watts steam engine， and Ford is assembly line are but a few devel
2、opments that are most noteworthy during our industrial period . Each of these developments has impacted manufacturing as we know it， and has earned these individuals deserved recognition in 0ur history hooks. Perhaps the single development that has impacted manufacturing more quickly and significant
3、ly than any previous technology is the digital computer. Since the advent 0f computer technology, manufacturing professionals have wanted to automate the design process and use the database developed therein for automating manufacturing processes. Computeraided design computer-aided manufacturing (C
4、ADCAM)， when successfully implemented, should remove the “wall” that has traditionally existed between the design and manufacturing components . CAD CAM means using computers in the design and manufacturing processes. Since the advent of CAD CAM， other terms have developed: Computer graphics(CG) Com
5、puteraided engineering(CAE) Computer-aided design and drafting(CADD) Computer aided process planning(CAPP) These spin-off terms a11 refer to specific aspects of the CAD CAM concept CADCAM itself is a broader， more inclusive term. It is at the heart of automated and integrated manufacturing. A key go
6、al of CAD CAM is to produce data that can be used in manufacturing a product while developing the database for the design of that product When successfully implemented, CAD CAM involves the sharing of a common database between the design and manufacturing components of a company, Interactive compute
7、r graphics (ICG) plays an important role in CAD/CAM, Though the use of ICG, designers develop a graphic image of the product being designed while storing the data that electronically make up the graphic image. The graphic image can be presented in a two-dimensional (2+D) , three-dimensional(3-D),or
8、solids format. ICG image are constructed using such basic geometric characters as points, lines, circles, and curves. Once created, these images can be easily edited and manipulated in a variety of ways including enlargements, 2 reductions, rotations, and movements. An lCG system has three main comp
9、onents :1 ) hardware, which consists of the computer and various peripheral devices； 2) software, which consists of the computer programs and technical manuals for the system ； and 3) the human designer, the most important of the three components. A typical hardware configuration for an ICG System i
10、nclude a computer， a display terminal, a disk drive unit for floppy diskettes, a hard disk, or both； and input/output devices such as a keyboard， plotter, and printer. These devices, along with the software, are the tools modern designers use to develop and document their designs. The ICG systems co
11、uld enhance the design process by allowing the human designer to focus on the intellectual aspects of the design process, such as conceptualization and making judgment-based decisions. The computer performs tasks for which it is better suited, such as mathematical calculations, storage and retrieval
12、 of data， and various repetitive operations such as crosshatching. Rationale for CAD CAM The rationale CAD CAM is similar to that used to justify any technology-based improvement in manufacturing . It grows out of a need to continually improve productivity，quality and， in turn competitiveness. There
13、 are also other reasons why a company might make a conversion from manual processes to CAD CAM: increased productivity better quality better communication common database with manufacturing reduced prototype construction costs faster response to customers Increased Productivity Productivity in the d
14、esign process is increased by CAD CAM. Time-consuming tasks such as mathematical calculations data storage and retrieval, and design visualization are handled by the computer， which gives the designer more time to spend on conceptualizing and completing the design. In addition, the amount of time re
15、quired to document a design can be reduced significantly with CAD CAM. All of these taken together means a shorter design cycle, shorter overall project completion time, and a higher level of productivity. Better Quality Because CAD CAM allows designers to focus more on actual design problems and le
16、ss 3 on time-consuming， nonproductive tasks， product quality improves with CAD CAM. CAD CAM allows designers to examine a wider range of design alternatives and to analyze each alternative more thoroughly before selecting one. In addition, because labor-intensive tasks are performed by the computer,
17、 fewer design errors occur. These all lead to better product quality. Better Communication Design documents such as drawings， parts lists, bills of material, and specifications are tools used to communicate the design to those who will manufacture it. The more uniform , standardized, and accurate th
18、ese tools are, the better the communication will be. Because CAD/CAM leads to more uniform, standardized, and accurate documentation, it improves communication. Common Database This is one of the most important benefits of CAD CAM. With CAD CAM the data generated during the design of product can be
19、use in product the product. This sharing of a common database helps to eliminate the age-old “wall” separating the design and manufacturing function Reduced Prototype Costs With manual design， models and prototypes of a design must be made and tested, adding to the cost of the finished product. With
20、 CAD CAM， 3-D computer models can reduce and, in some case, eliminate the need for building expensive prototypes. Such CAD CAM capabilities as solids modeling allow designers to substitute computer models for prototypes in many cases. Faster Response to Customers Response time is critical in manufac
21、turing. How long does it take to fill a customers order? The shorter the time, the better it is. A fast response time is one of the keys to being more competitive in an increasingly competitive marketplace. Today, the manufacturer fastest response time is as likely to win a contract as the one with
22、the lowest bid. By shortening the overall design cycle and improving communication between the design and manufacturing components, CAD CAM can improve a companys response time Historical Development of CAD CAM The historical development of CAD CAM has followed close behind the development of computer technology and has paralleled the development of ICG technology. The significant developments leading to CAD CAM began in the late 1950s and early 1960s. The first of these was the development, at Massachusetts Institute of Technology (MIT)， of
