Computer Aided Mechanical Design

More and more, industry professionals are turning to computer modeling software to help design machines, factories, assembly plants, and civil engineering projects in addition to the products and tools they manufacture. This paper will take a closer look at the growing field of computer-aided manufacturing design, discussing the use of such technologies as well as their applications in the important arenas of architecture, manufacturing, and the medical device industry.

Keywords: Automated Drafting and Machining (ADAM); Computer-Aided Design (CAD); Modeling Software; SKETCHPAD; Stereolithography; Virtual Reality

Overview

The famed science-fiction author Isaac Asimov once reportedly commented, "I do not fear computers," adding, "I fear a lack of them." Indeed, the modern world has become heavily dependent on computer technology, which has become vital for virtually every aspect of life in the twenty-first century—invaluable for commerce, education, government, health care, and even the simplification of household affairs.

Computer technology has also become a key component in organizing and processing data. It is also being used increasingly in crafting a road to the future. Weather forecasters use computer modeling and imagery to better predict storm patterns, and economists use similar technologies to help understand market trends of the present and the near future. Computer modeling software is even used in hospital and medical research facilities, helping doctors and medical professionals track patient responses to medications as well as to better conduct surgical procedures.

The manufacturing and engineering industries are no exception. More and more, industry professionals are turning to computer modeling software to help design machines, factories and assembly plants, and civil engineering projects in addition to the products and tools they manufacture. This paper will take a closer look at the growing field of computer-aided manufacturing design, discussing the use of such technologies as well as their applications in a number of important arenas.

A Brief History of Computer-Aided Design (CAD)

The practice of using computers for the purposes of designing complex machinery and systems began in the early 1960s, although it was conducted privately with specific design purposes in mind. Specifically, the automotive, electronics, and aerospace industries employed such design techniques through automated 3-D modeling programs ("History of CAD," 2009).

Early computer-aided design (CAD) programs, however, were extremely complex, expensive, and required massive computer hardware systems to conduct their calculations. Few industries could afford to support such systems. Among the companies that did utilize such systems were US automaker General Motors, US aerospace giant Lockheed, and European automaker Renault. These applications stemmed from the 1963 program known as SKETCHPAD, which was created by MIT scientist Ivan Sutherland. That system, for the first time, contained a feature that enabled the designer to interact with his or her computer through graphics. Such a graphical user interface (GUI) would ultimately become indispensable in CAD circles.

Particularly notable among these systems were the works of Dr. Peter J. Hanratty, who in 1964 introduced Design-Augmented by Computer (DAC-1) for GM. In 1971, Hanratty rolled out the program known as Automated Drafting and Machining (ADAM); not long after he started his own firm, Manufacturing and Consulting Services, Inc. Shortly thereafter, Hanratty began offering code to a number of companies outside of the three discussed above. Among the industry leaders who would adopt similar design programs were Computer Vision, baby food manufacturer and supplier Gerber, and McDonnell Douglas. Thanks to the work of such figures as Hanratty and Sutherland, early versions of CAD systems became increasingly popular among large corporations. Unfortunately, the size and cost of computer systems in general, along with the costs of systems specific to this purpose, left CAD applications largely beyond the reach of smaller businesses.

In the late 1970s, computer technology became more compact and affordable. With this came an evolution of CAD programs, which increased in terms of capability and versatility. By the early 1980s, CAD programs were able to create more complex, interlinked models as well as design in clearer 3-D settings (previous incarnations utilized a simpler, 2-D format). Such modified systems led to greater interconnectivity among design models (Raj, 2007). By the late 1980s, CAD technology was considerably more sophisticated and more widespread in its use than it had been only two decades earlier. An example may be found in the introduction of PTC Pro/Engineer, a system that used parametric design programs, which allow for greater connectivity with other design models through the application of historical data. This "history-based" approach became, for a few years, popular among engineers who had previously used 3-D modeling in their work. The debate over history-based versus history-free programs has continued into the twenty-first century (Stackpole, 2009).

Introduced in the 1970s, the personal computer (PC) saw a rapid evolution over the next two decades. The prevalence of smaller, multiple-unit computer terminals allowed a larger number of engineers, computer scientists, and design professionals to both use existing CAD programs as well as create modified versions for their own purposes. CAD systems became more common and had greater capabilities — some systems allowed the user to manipulate 3-D shapes, while others created greater parametric connectivity that allowed for the development of extensive and more complex design models.

In the twenty-first century, computer-aided design systems are some of the most popularly used computer programs by major corporations and certain industries of all sizes and industry areas. This paper will next turn to a few examples of how CAD is employed in the twenty-first-century global economy.

Applications

Architecture

Prior to the introduction of computer software, architects relied on careful, manual mathematic calculations and drawings. Architectural drawings and blueprints have long been essential for those doing the work and the clients who seek to have the work done. Such drawings are also useful for government officials who may or may not approve funding and/or zoning for such work and also prove practical for other contractors who are performing landscaping or other external work.

Central to any construction or manufacturing industry is the design stage. In this phase, the engineer is expected to create from a visual ideal a valid structure or mechanism that will appear in a certain way while it performs the task for which it is created. In architecture, the design is crucial, for it not only enables all parties involved (the construction contractors, the client, and others) to see the realized schematic, it also helps them understand the structural integrity and viability of the building.

In the global economy, architecture is essential to the manufacturing industry. Factories and production plants require configurations that are conducive to the manufacturer's needs and budgets. Architects must take into account energy source distribution and space for heavy machinery, and attempt to find ways to help the client save on expenses over the long term. With a growing international marketplace that fosters increased competition among manufacturers, architecture is playing an invaluable role.

Like so many other construction- and manufacturing-oriented industries, the field of architecture quickly embraced the introduction of CAD technologies due to the fact that it offers improvement in both the process and product of architectural design. Additionally, CAD saves on labor, helping create designs in an efficient yet comprehensive and accurate manner. In fact, it has been argued that CAD's continuous evolution consistently offers the architect an opportunity to see design in a whole new light without compromising his or her creativity. For some architects, however, there was a concern that CAD might assist in the creation of extensive design schematics but not necessarily operate in the abstract. For example, CAD systems might not take into account rooftop structures long established in the industry, and others might not include construction materials in the design process (Lawson, 2002).

Over time, CAD systems, which could produce both 2-D and 3-D structural models, have come to largely replace hand drafting in the field of architecture. However, the models created in the early architectural CAD programs provided only an aesthetic sense of the proposed building, and models for actual construction, with necessary specifications, had to be created in separate software (Epstein, 2012). Consequently, there has been a push to integrate building information modeling (BIM) with CAD for architectural design modeling. In BIM-based CAD programs, real-world specifications for items such as doors and windows are available directly in the same software that architects use to create their 3-D models and derive their 2-D drawings, thereby preventing avoidable errors from occurring downstream, avoiding redundancies, and saving time on project changes (Epstein, 2012; Yi-Feng & Shen-Guan, 2013).

Manufacturing

CAD has proven increasingly useful for fields that require the creation of models that connect complex systems. The development and construction of manufacturing facilities entails the establishment of a model that blends structural integrity, electrical capacity, and other vital yet intricate systems.

The heavy machinery and related systems that are part of a manufacturing facility require a similar design approach. Such machines have a wide range of parts, each of which entails careful definition. Many of these parts are geometric in origin; the design of the overall system involves the modeling of a number of geometric shapes (Teller, 1996). Computer programs have increasingly been utilized for the purposes of creating such models. The 3-D and layering abilities (also known as “stereolithography”) of an ever-increasing array of CAD programs have become central to this endeavor.

However, since CAD's applications to the manufacturing industry became evident in the 1970s, a persistent problem has arisen. While CAD software has long been adroit in reconciling and designing geometric shapes, they have historically been limited to known geographic shapes, unable to see beyond such contours. CAD developers have therefore worked to increase the learning capacity of such programs so that they are able to recognize shapes beyond their limited caches (Qiang & Marefat, 1997). Such efforts remain challenging, as computer systems must be programmed to recognize patterns and features, not just standard geometric shapes but their compositions as well. Put simply, in order to help CAD programs move beyond their original parameters, programmers have attempted to install an ability to operate with a degree of "intelligence."

While CAD has demonstrated its shortcomings in the above-mentioned arenas, it remains an important element of the manufacturing sector. Programmers, looking to remedy these issues, are increasingly looking to other software and hardware resources to fill in where CAD has come up short. One area, for example, was the introduction of virtual reality (VR) programs. VR employs a degree of human-computer interface that is considerably quicker than that seen in typical CAD programs. VR therefore injects into the design and modeling process the user's ability to see the entire environment, including the areas that CAD historically simply could not take into account (Jezernik & Hren, 2003).

Another issue revealed in the application of CAD to the manufacturing sector is one of process. Because it has had problems with recognition of nongeometric shapes, the process of manufacturing design has been slowed considerably. However, by applying another program to CAD systems, such as rule-based reasoning, these recognition problems may be circumvented. Other programs, such as the Standard for Exchange of Product Model Data (STEP), have been used as information resources for CAD, enabling the system to interconnect its database and link together complex processes or multiple groups (Lau et al., 2005).

Medical Devices

The twenty-first-century global economy has had a major impact on how industries develop. The fact that so many markets are merging into a singular, international network means substantially increased competition. While this has so far caused only modest growth in competition for such established manufacturing industries as aerospace and automobiles, other growing industries are suddenly faced with much greater amounts of pressure. This places heightened emphasis not only on the quality of products manufactured (and the prices at which they are sold), but also requires that those products be produced in higher quantities at a much faster rate.

In the field of medical device manufacturing, for example, this trend has become particularly evident. This industry has seen durable rates of growth and revenue generation in the 2000s and 2010s. In the US alone, this industry generated $75.6 billion in 2007 ("Advertising with," 2009), and it is forecasted to reach $302 billion by 2017, with a compounded annual compounded growth rate of 6.1 percent between 2011 and 2017 (Lucintel, 2012). Interestingly, the industry is mostly composed of small- to medium-sized businesses that employ fewer than 50 people. Such volumes of small firms mean a more dynamic industry comprising sales teams that are eager to earn new business.

For this reason, medical device manufacturers are increasingly turning to CAD technologies to expedite the development and, ultimately, distribution of their products. CAD software has therefore come into high demand, following in the shoes of more established corporations in other industries that have long enjoyed the application of such software to their own manufacturing endeavors.

Unfortunately, the traditional applications of CAD software and systems have to date proven somewhat daunting for the many small companies that make up the medical device manufacturing industry. As mentioned, such systems have long been confined to large and very expensive computer frameworks available typically to larger and more fiscally healthy organizations. Small medical device manufacturers typically have less financial stability and revenue growth, especially in a tight, highly competitive market.

The growing demand among medical device manufacturers has thus facilitated the evolution of CAD software. In order to enable a more cost- and space-effective application of CAD systems, the program developers are seeking ways to make such technology more accessible for a broader contingent of industries. In the case of medical device manufacturers, CAD developers are modifying the software to make it more applicable to PC systems.

By 1995, at least three major CAD companies were developing this technology, utilizing the platforms established by the Windows NT system on the foundation laid by UNIX-based systems. UNIX was previously one of the only ways CAD could be utilized on more high-performance workstations. Since the introduction of Windows NT and subsequent Microsoft systems, there has been a confluence of capabilities for full versions of CAD to be used on a PC (Freiherr, 1995). Such developments mean that medical device manufacturers have greater access to computer-based, multidimensional design systems that can expedite the development, assembly, and distribution of their products.

Conclusions

Karl Marx once cautioned, "The production of too many useful things results in too many useless people" (as quoted in Andrews, 1993, p. 936). Throughout history, a common pursuit has always been to use technology to benefit humanity. In the twenty-first century, this theme is particularly relevant. The global economy is one in which competition is increasing quickly. As a result, demand for efficient rates of production has risen significantly, and the use of cutting-edge technology remains the key to the acquisition of such projects.

It is for this reason that CAD systems were created. They offer many of the same capabilities that more traditional design tools create but usually at a much faster and usually more reliable rate. In its earliest stages, CAD was of particular use to those industries that sought to manufacture large numbers of complex mechanical systems, such as airplanes and automobiles. The speed at which CAD could process the intricate shapes and components that would ultimately comprise the product helped the automobile and aerospace manufacturers maintain a distant lead over competitors.

However, the shortcomings of CAD programs have long been evident. First, many CAD programs require workstations that are large, singular in purpose, and expensive. It is for this reason that, until the 1990s and 2000s, few industries were able to utilize CAD systems. Second, some CAD systems have limitations in terms of the shapes they can recognize, which may temper the speed by which the design process moves. Many designers, including architects, have expressed disdain over the use of CAD because of the systems' perceived lack of creativity — a necessary tool for most architects and innovators.

Then again, like most forms of computer software and systems, CAD programmers are constantly adapting to the demands of would-be consumers and therefore introducing evolved versions of this software and its applications. The enormous, expensive CAD systems of the past are increasingly giving way to less expensive PC applications, which appeal to the smaller manufacturer. Additionally, much of this software is being improved to address its previous recognition limitations as well as render it more adaptable to a variety of applications. CAD programs are being constantly upgraded and modified to suit the twenty-first-century global economy, making each software and system incarnation appealing to a growing number of industries.

Terms & Concepts

Automated Drafting and Machining (ADAM): A 1971 program created by Peter Hanratty; one of the first commercially applied CAD programs.

SKETCHPAD: The 1963 predecessor to CAD programs created by Ivan Sutherland.

Stereolithography: Design software that creates models using a layering technique.

Virtual Reality: Computer program designed to create the highest level possible of user and program interface.

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Suggested Reading

3D CAD speeds the design of medical devices. (2005). Professional Engineering, 18, 43. Retrieved August 14, 2009 from EBSCO Online Database Business Source Complete. http://search.ebscohost.com/login.aspx?direct=true&db=buh&AN=16358406&site=ehost-live.

Hirz, M., Harrich, A., & Rossbacher, P. (2011). Advanced computer aided design methods for integrated virtual product development processes. Computer-Aided Design & Applications, 8, 901–913. Retrieved November 25, 2013 from EBSCO online database Business Source Premier. http://search.ebscohost.com/login.aspx?direct=true&db=buh&AN=67616648

Horgan, J., & Pinson, M. (1992). Machines that make CAD happen. Design News, 48, 62–64. Retrieved August 14, 2009 from EBSCO Online Database Academic Search Complete. http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=17331872&site=ehost-live.

Seth, A., & Smith, S. (2004). PC-based virtual reality for CAD model viewing. Journal of Technology Studies, 30, 32–37. Retrieved August 14, 2009 from EBSCO Online Database Academic Search Complete. http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=18753294&site=ehost-live.

Switch to PC-based CAD brings unexpected benefits. (1999). Design News, 55, 47, 49. Retrieved August 14, 2009 from EBSCO Online Database Academic Search Complete. http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=1794561&site=ehost-live.

What's hot in CAD. (2012). Machine Design, 84, 62–63. Retrieved November 25, 2013 from EBSCO online database Business Source Premier. http://search.ebscohost.com/login.aspx?direct=true&db=buh&AN=79552561

Zheng, J. M., Chan, K. W., & Gibson, I. (2001). Desktop virtual reality interface for computer aided conceptual design using geometric techniques. Journal of Engineering Design, 12, 309. Retrieved August 14, 2009 from EBSCO Online Database Academic Search Complete. http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=5692011&site=ehost-live.