CAD/CAM Revolutionizes Engineering and Manufacturing

Date 1980’s

The popular use of computers to design buildings and mechanical parts can be dated to the groundbreaking release in 1982 of the software product AutoCAD. Computer-aided design (CAD) and computer-aided manufacturing (CAM) enhanced flexibility in engineering design, leading to higher-quality products and reduced time for manufacturing.

Locale United States

Key Figures

• Ivan Sutherland (b. 1938), Ph.D. student at the Massachusetts Institute of Technology who wrote the revolutionary industrial design software Sketchpad for his thesis
• Patrick J. Hanratty (b. 1931), computer scientist known as the “father of CAD/CAM”
• John Walker (b. 1949), founder of the company Autodesk, which devised AutoCAD, the first popularly accessible software for designers

Summary of Event

Architects and mechanical parts designers once planned their buildings and machines with pencil and paper only, making elaborate blueprint drawings. Much of this method changed in 1982 with the groundbreaking introduction of computer software useful for vehicle design called AutoCAD, released by a company called Autodesk. By the end of the twentieth century, many architects and mechanical designers were working on computers using specialty software that enables computer-aided design (CAD) and computer-aided manufacturing (CAM): CAD/CAM software.

Long before Autodesk released AutoCAD, the idea of using a computer to design buildings and mechanical parts was being explored by the military and the Massachusetts Institute of Technology (MIT). Semi-Automatic Ground Environment (SAGE), an air defense system, began testing in the 1950’s; Sketchpad, a program created by MIT’s Ivan Sutherland, focused on industrial uses. Sketchpad was revolutionary in its ease of use: The user entered a design into the computer simply by drawing on the computer’s monitor with a light pen. Automobile manufacturer General Motors realized the importance of the technology to vehicle design and began to experiment with making software. Lockheed, Renault, and others followed suit. Many of these companies used software and code invented by the “father of CAD/CAM,” Dr. Patrick J. Hanratty.

The now-famous two-dimensional design software AutoCAD was developed by the firm Autodesk, which was started in 1982 by John Walker. Computer design in two dimensions became augmented by design in three dimensions. The momentum increased as computer memory grew and as computer monitors became larger. Thus, during the 1970’s, when computers were becoming increasingly affordable, the software was used to make industrial tools and to do solid modeling; in the 1980’s, a three-dimensional program from Graphsoft and CAD for the Mac were released. The 1990’s saw hybrid modeling and template control (from Unigraphics). At the end of that decade, Think3’s products allowed users to work simultaneously with wire frames, advanced surfacing, and parametric solids and to do other two-dimensional drafting tasks.

CAD/CAM designers (who usually work with Windows software on desktop computers) can use the software to do many different tasks, such as creating wire frames, solid models, and part assemblies. The programs can shift from solid models to engineering drawings. The user creates designs either by using a computer mouse or by writing directly on a computer tablet. In 1997, the CAD program CATIA was used to design—on time and within budget—the spectacular Guggenheim Museum Bilbao in Spain, designed by Frank Gehry.

In addition to its use in designing buildings and machine parts, the software is now applied to other uses and products, such as textile design, milling, piping, hose and cable routing, heating and cooling units, welding, forging, engraving, laser use, shipbuilding, aerospace, electrical and biomechanical systems, printed electronic circuit boards, and even the design of tiny nano parts and intricate gardens.

Essential to any CAD/CAM user is the idea of geometric tolerancing. By using the principles of tolerancing, designers are able to make parts that exactly fit other parts, to make a whole unit. A CAD/CAM program can tell a designer if a part is matching its specifications; the program analyzes curves and checks assemblies for kinematics, interference, and clearance. A parts design operator can also manipulate the program to output the design to a rapid prototyping machine, to make a rough physical copy of the designed item.

Finite element analysis is beginning to be an important part of CAD/CAM. This analysis uses linear algebra or nonlinear algebra and combines equations about compatibility, constitutive relations, and equilibrium. The method can refine how a complex model looks in CAD/CAM, and it is useful to determine stresses and solve problems in heat transfer, electromagnetism, fluid dynamics, and other types of reactions.

Early CAD systems used a computer language called FORTRAN. By the early twenty-first century, CAD/CAM programs were focused on the object and based in C programming language, where the operator works with a graphical user interface. Curves and surfaces are made with a type of geometry called NURBS. The boundaries of the objects are important data that define the shapes of the designed parts, and this concept is called B-rep. A type of software called “geometric modeling kernel” allows the operator to make use of B-rep.

Significance

Prior to CAD/CAM, designers worked with the basics—pencils, erasers, and rulers. The power of computers to help operators more easily create, alter, and store three-dimensional designs has revolutionized the global marketplace. The software can allow a user to produce amazing walk-throughs, enabling a prospective client to examine a building from inside and outside. Operators can work more efficiently and can control a product from design to the end of the product’s life. The software can even design standard parts automatically. Products can be designed for one purpose and can easily be redesigned to fit new purposes. Thus, the user can keep an immense library of designs, manage manufacturing processes, and control material waste.

This long-range control allows companies to cut waste and consider the environmental impacts of their products. Companies can more easily redesign products to be unique to the countries in which the products are to be sold, which is a big advantage in the global marketplace. Computers decrease the time needed from design to production, and new software even simulates stress tests. When CAD/CAM added communication features, staff in all areas of the business became much better connected.

For companies producing products in mass quantities, CAD/CAM technology is invaluable. In particular, machines run by computer numerical control (CNC) have been vastly improved in accuracy by CAD. CAM sometimes is part of a CNC machine, so that the CAM program operates the machine, with a person managing its work, to achieve such tasks as drilling holes into metal at precise intervals. The merger with CNC and CAD made the machines faster, cheaper to use, and much easier to monitor.

Bibliography

Andrews, Wen. CAD Tools for Interior Design. San Rafael, Calif.: Autodesk, 2007. Explains Autodesk Architectural Desktop and VIZ by starting with basic working drawings. An informative close-up guide to creating virtual model walk-throughs, three-dimensional work, and animations.

Cozzens, Richard. Advanced CATIA V5 Workbook: Knowledgeware and Workbenches Release 16. Mission, Kans.: Schroff Development Corporation, 2006. Cozzens spent many years as an engineer for companies like Boeing before going into teaching full-time. This book imparts an insider’s mastery of Sketcher, part and assembly design, drafting, stress analysis, kinematics, prismatic machining, and working with sheet metal designer. Contains a useful glossary.

Dimarogonas, A. D., ed. Machine Design: A CAD Approach. New York: John Wiley & Sons, 2001. Case studies and explanations about using computers to design complex mechanical systems. Gives practical examples—with seven hundred illustrations—of the methods for designing numerous items. Includes essential details about material fatigue, stress, friction, and oiling.

Green, Robert. Expert CAD Management. Berkeley, Calif.: Sybex, 2007. Reviews the skills needed to be a CAD manager, from technical and managerial savvy to business skills. Informs the reader about real-world solutions to business problems such as budgeting, creating standards, training, and buying and installing hardware and software. Provides tips to succeeding on the job.

Kutz, Myer. Environmentally Conscious Mechanical Design. Hoboken, N.J.: John Wiley & Sons, 2007. Provides CAM designers with the foundations of design that meets environmental regulations. Introduces ways to design a product for its entire life cycle. All types of products are discussed: industrial, business, and consumer.

Shih, Randy H. Parametric Modeling with Autodesk Inventor R11. Mission, Kans.: Schroff Development Corporation, 2006. Features a tutorial-style format to teach parametric modeling, constructive solid geometry, part drawing, associative functionality, symmetrical features, assembly modeling, and other construction topics. Shows readers how to build solid models and create multiple-view drawings.

Simpson, Timothy W., Zahed Siddique, and Jianxin Jiao, eds. Product Platform and Product Family Design. New York: Springer, 2007. Shows the CAM designer how companies like Sony, Kodak, and Black and Decker implement product family design.