Automated drafting
Automated drafting capabilities in CAD systems facilitate presentation, which is the final stage of the design process. CAD data, stored in computer memory, can be sent to a pen plotter or other hard-copy device (see Section 6.2) to produce a detailed drawing quickly and easily. In the early days of CAD, this feature was the primary rationale for investing in a CAD system. Drafting conventions, including but not limited to dimensioning, crosshatching, scaling of the design, and enlarged views of parts of other design areas, can be included automatically in nearly all CAD systems. Detail and assembly drawings, bills of materials (BOM), and cross-sectioned views of design parts are also automated and simplified through CAD. In addition, most systems are capable of presenting as many as six views of the design automatically. Drafting standards defined by a company can be programmed into the system such that all final drafts will comply with the standard.
Further, CAD systems can operate with other software applications to add to their presentation flexibility (Fig. 11). Documentation of the design is also simplified using CAD. Product data management (PDM) has become an important application associated with CAD. PDM allows companies to make CAD data available interdepartmentally on a computer network. This approach holds significant advantages over conventional data management. PDM is not simply a database holding CAD data as a library for interested users. PDM systems offer increased data management efficiency through a client–server relationship among individual computers and a networked server. Benefits of implementing a PDM system include faster retrieval of CAD
files through keyword searches and other search features; automated distribution of designs to management, manufacturing engineers, and shop-floor workers for design review; recordkeeping functions that provide a history of design changes; and data security functions limiting access levels to design files. PDM facilitates the exchange of information characteristic of the emerging agile workplace. As companies face increased pressure to provide clients with customized solutions to their individual needs, PDM systems allow an increased level
of teamwork among personnel at all levels of product design and manufacturing, cutting the costs often associated with information lag and rework.
Although CAD has made the design process less tedious and more efficient than traditional methods, the fundamental design process in general remains unchanged. It still requires human input and ingenuity to initiate and proceed through the many iterations of the process. Nevertheless, CAD design is such a powerful, time-saving design tool that it is now difficult to function in a competitive engineering world without such a system in place. The CAD system will now be examined in terms of its components: the hardware and software of a computer.
COMPUTER-AIDED DESIGN
Emory W. Zimmers, Jr. and Technical Staff
Enterprise Systems Center
Lehigh University
Bethlehem, Pennsylvania
Mechanical Engineers’ Handbook: Materials and Mechanical Design, Volume 1, Third Edition.
Edited by Myer Kutz
Copyright 2006 by John Wiley & Sons, Inc.
