Manual Computer Based Design and Manufacturing

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Contents:


  1. 5 Things You Should Know About Computer Aided Design, A Product Engineer's Secret Weapon
  2. Computer Based Design and Manufacturing
  3. Computer-aided design/History, Present and Future - Wikiversity
  4. Automation in daily life

It was the first significant solid modeler for Windows. This was followed by Solid Edge, Inventor, and others. The modern CAD era has been marked by improvements in modeling, incorporation of analysis, and management of the products we create, from conception and engineering to manufacturing, sales, and maintenance what has become known as PLM, product lifecycle management.

But what of the world of tomorrow? PTC is taking a similar approach with the recent announcement of its Project Lightning, which was revealed as Creo in October. But parametric modeling is an abstract approach for creating geometry. Creo promises to do just that by releasing a series of apps that allow users to design in 2D, 3D direct or 3D parametric modes, with the data updated and reusable in any of those modes.

It also offers different user interfaces for different kinds of users, and promises to allow users to incorporate data from any CAD system. Not surprisingly, Kross is enthusiastic. It depends on who you ask. Everyone knows that except big CAD companies. Maybe free. Utilizing the increasing number of CPU cores is essential to future implementations, while utilizing GPU cores will likely remain specialized.

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5 Things You Should Know About Computer Aided Design, A Product Engineer's Secret Weapon

Multi-threading provides great benefits for things like analysis and rendering, but most people want to see improved speed in geometry regeneration, which is fundamentally a serial process. What about touch-based and gesture based interfaces? Consistent with its use in the design community and by other researchers, CAD encompasses the entire process of creating, modifying, and verifying designs with computer-based tools.

It also encompasses the three principal elements of the computer-based design workplace: designers, design tools, and design tasks. The central question addressed in this chapter is, when CAD technology increases the productivity of individual designers, under what conditions will those increases lead to increases in the productivity of the design team and, in turn, the design organization? Many of the issues discussed in earlier chapters are relevant to this type of information work—particularly the inhibitors and facilitators of linkages discussed in Chapter 3 and the coordination and communications concepts discussed in Chapter 9.


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I examine these and other issues here as they relate to productivity linkages among designers, design teams, and engineering organizations. I also assess influences that are likely to operate through these linkages to affect CAD productivity at different levels of analysis. Finally, I identify the types of research needed to understand these linkages and influences better and to define their role in the productivity of organizations.

The observations made in this chapter are based in part on the findings of other researchers, and in part on the results of a study a colleague and I made of the effectiveness of CAD within the engineering design organizations of a large aerospace company see Harris and Casey,. Although our study did not address linkage issues directly, the data we obtained and the experience we gained in collecting them provide a rich source of information for examining linkage issues.

In exploring the CAD domain, it is important to recognize that CAD is but one part of a larger evolving industrial process.

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Companies throughout the world have been attempting to achieve productivity gains by introducing computer-based tools in their engineering and manufacturing organizations. Companies in the United States, in particular, have been investing in CAD as a means of meeting the challenge of foreign competitors. Increased productivity is expected to come from automating routine tasks, increasing the efficiency and accuracy of complex calculations and tests, replacing physical prototypes with electronic prototypes, and facilitating the sharing of design data and the products of design tasks.

Despite these expectations, however, previous studies conducted in several countries suggest that, thus far, the productivity potential of CAD has seldom been realized Beatty and Gordon, ; Liker and Fleischer, ; Majchrzak et al. Another aspect of the evolving industrial process is the important interface between CAD and computer-aided manufacturing CAM. Computer aiding for engineering design has evolved from the development of relatively simple computer-based tools for drafting into sophisticated computer-based systems intended to streamline the entire design process.

Computer aiding for manufacturing has evolved from numerically controlled machines into entire computer-based production facilities. For example, a special committee of the National Research Council studied companies that were utilizing both CAD and CAM and strongly recommended pursuing the productivity gains that it believed could be realized through better integration of the two.

Thus, although the focus here is on CAD, productivity linkages extend as well to the industrial enterprise of which CAD is only a part. As noted above, Harris and Casey's study of the engineering design activities of a major aerospace company provides the principal data for this examination of productivity linkages in CAD. At the time of the study, the aerospace company had spent hundreds of millions of dollars on CAD hardware, software, facilities, and training.

In addition, the company's design engineers had accumulated several years of CAD experience. The main purposes of the study were to document the. The study was conducted by first analyzing the computer-based tools and the tasks for which they were being used, then observing and interviewing users of the tools, and finally, surveying the users of the tools on factors influencing CAD effectiveness.

The study focused on the designers who had been the most frequent users of CAD tools during the previous year out of a design engineering population of about 1, in the organization studied. These designers were identified from logs maintained by the system for the previous year. The CAD domain was defined by identifying the specific design tasks that were being performed and then categorizing the tasks into a set of principal activities. The design tasks thus identified could be categorized relatively easily into four principal CAD activities.

This four-activity definition of the CAD domain was consistent with the findings of other investigators e. These four activities are summarized in the four sections that follow. Creation or modification of two-dimensional drawings includes all tasks required for the preparation of two-dimensional drawings of various types, such as plan views and projections. These tasks are directly analogous to the tasks that, prior to the development of computer-based tools, were completed at drawing boards.

Computer-based tools available in CAD automate many of the labor-intensive details of this process, such as providing lines of selected widths, creating and positioning text, providing dimensions, filling and shading, and manipulating and correcting drawing elements. Computer aiding of this activity does not really extend the capability of the designer, rather it automates drafting functions in an attempt to make them more efficient and to make their products more consistent. Creation or modification of three-dimensional models encompasses the development of three-dimensional formulations of designs and their manipulation on computer displays.

This activity is analogous to the tasks that, prior to CAD, required the construction and direct manipulation of physical models. With CAD, many of the manipulations that were previously performed physically, such as checking the fit of parts and examining the movement of working parts, are now performed elec-. Models can be constructed with varying degrees of sophistication, from simple wire-frame representations to realistic, shaded-solid representations in full color.

Verification of drawings and models includes the tasks required to verify that design parameters meet design specifications. Design work is completed under sets of specifications that provide design criteria and constraints for the end product. Consequently, a significant amount of design activity is devoted to ensuring that design concepts and intermediate products drawings and models meet those specifications.

Because these tasks might require the completion of some basic calculations, CAD provides appropriate algorithms and calculation capabilities. Acquisition of design data encompasses tasks involved in obtaining the information needed for the solution of design problems, including the retrieval of information from CAD data bases.

Given that engineering is the application of knowledge to the solution of technical problems, a part of the design effort necessarily involves the acquisition of information that is appropriate to the problem. Prior to CAD, engineers relied heavily on information contained in printed materials, such as handbooks, and on personal interaction with supervisors, specialists, and colleagues to obtain needed information.

With CAD, these traditional sources of information are augmented by data bases supported by computer-based systems.

Computer Based Design and Manufacturing

Acquisition of data also encompasses data transfer from one workstation to another or to other functions, such as CAM. Typically, CAD is introduced into an engineering design organization with the expectation that it will increase the productivity of the organization by increasing the productivity of individual designers. Productivity gains are anticipated from the capabilities of CAD to automate routine functions, enhance the accuracy and efficiency of design tasks, promote the exchange of information, and facilitate the performance of sophisticated design tasks.

Thus, the principal facilitator of productivity is assumed to be the technology of the CAD system itself. However, it is the interaction of the characteristics of the CAD. The principal output of a design effort is a set of design products drawings, models, descriptions, and lists that meet agreed design objectives, guidelines, and constraints.

The principal resource consumed in producing this output is labor—designer, support, administrative, and so on. Thus, regardless of the level of analysis individual, group, department, organization , the core definition of productivity within this domain is the ratio of design output to labor input. Within the framework defined by the four types of design activities described above, my colleagues and I examined system and domain characteristics for factors that might facilitate or inhibit the productivity of the design organization.

Our interviews and surveys of designers produced 3, specific comments on various aspects of CAD effectiveness. Analyses of these comments produced issues that we then categorized into 43 principal factors associated with CAD performance. From these results, we identified characteristics of the CAD domain that might influence, positively or negatively, the design productivity of individuals, teams, and organizations.

These potential influences on productivity linkages in the CAD domain are presented in Figure and discussed below. The work of individual designers in the aerospace company appeared to be relatively specialized in terms of the four principal design activities described earlier. Many designers concentrated on just one or two. For example, more than 60 percent of those who reported doing any three-dimensional modeling spent at least 80 percent of their time on that activity.

Computer-aided design/History, Present and Future - Wikiversity

Nearly 40 percent of those who reported doing any design verification spent at least 80 percent of their time on that activity. The levels of specialization for two-dimensional drawing tasks and for data acquisition tasks were also within these ranges. Design work was specialized, therefore, not only by what was being designed e. Specialization of design work can facilitate the productivity of the individual designer because it encourages the more rapid development and application of design skills.

However, it might inhibit the realization of productivity gains at the team and organizational levels because of the greater administrative burdens required for coordination and communication. These burdens were discussed in Chapter 9 relative to the software development domain. Similar findings were reported by Liker et al. They found that a high degree of specialization was characteristic of the design organizations they studied, and that a high degree of fragmentation and segmentation existed in the application of knowledge and skills to the design process.

They found that, commonly, the design process was divided into many little pieces and that each piece was delegated to a separate designer. A relatively common complaint voiced by CAD designers in the aerospace company was that their work was too isolated from their supervisors and their senior associates and that it suffered as a consequence. The relatively frequent, informal, personalized guidance and feedback that designers had become accustomed to while working at drafting boards were reported to be lacking with CAD.

Perhaps the utilization of a CAD workstation is not conducive to the provision of the kind of guidance, communication, and feedback designers consider important. The productivity of the individual designer, as well as that of the design team and organization, may be inhibited because of these difficulties.

Use of CAD may require special efforts and methods to overcome the potential handicap of designer isolation. Within the aerospace company many more designers used CAD workstations than there were workstations for them to use—about 1, This finding is consistent with observations reported by others to the effect that, particularly in larger organizations, resources tend to lag the need for them. For example, Liker and Fleischer reported that CAD is typically phased in gradually over an extended period of time because of the extensive investment required in workstations and the cost of transferring pre-CAD designs to CAD.

Although nearly all of the 1, designers in the aerospace company had received the basic training required to qualify them to use CAD, about half of them seldom if ever used a CAD workstation. Excluding the infrequent users, on the basis that their need was not great, approximately designers had to time-share among the workstations. Among those , the distribution of time spent on CAD was highly skewed.

The most frequent users reported averaging The need to time-share workstations is a potential inhibitor of productivity gains. The designers surveyed reported that they spent an average of 3. Because of the serial nature of many design tasks, waiting time is likely to be only marginally productive. Other possible inefficiencies associated with time-sharing include those associated with the additional effort required by the individual, team, and organization for scheduling workstations, and the nonproductive time and effort involved in moving and transporting working materials between two locations e.

Automation in daily life

As with other computer-based systems, the technology that supports CAD has been evolving rapidly and is expected to continue to do so for many years to come. In turn, a company's efforts to maintain or improve its competitive position force older technology to give way to the new. As a consequence, the technology employed in CAD is typically in a state of transition.

One assumption, of course, in introducing new technology is that it will result in further productivity gains for the enterprise. The introduction of new hardware and software is also a potential source of productivity loss due to the turbulence it generates in the CAD working environment.

In the aerospace company, the pool of Workstations consisted of newer and older models from the same vendor, as well as newer models under evaluation from other vendors—all differing in important ways in the features and the interfaces they provided for the designers. As discussed in Chapter 2 , changes in hardware and software can be particularly devastating to productivity in activities in which skills are not easily acquired. Computer-aided design is one of those activities.

In the aerospace company designers estimated that, on average, 9. Additional time was required to reach an adequate level of proficiency on tasks that they previously were unable to perform manually, such as three-dimensional modeling. These estimates are higher than those obtained by other investigators, probably because of differences in the nature of the design tasks.

For example, Beatty obtained an estimated average of 4. Even when the lower estimate is used, it must be concluded that a relatively lengthy period of specialized training and experience is needed to reach an adequate level of proficiency in CAD skills. A system change with great negative impact on the designers surveyed was the introduction of new or updated applications software. Several months before the study, a major updating of the CAD software had been introduced.

The change itself created a substantial burden associated with unlearning parts of the old system and learning the new versions. These difficulties were intensified, however, by problems in the software itself.

Computer Integrated Manufacturing -Elements of CIM - Functions - PPT - ENGINEERING STUDY MATERIALS

Inevitably, it seems, newly released or updated software does not function exactly as it is supposed to, even when subjected to extensive pretesting. These software development difficulties can combine with long proficiency-development lead times and transfer-of-training problems to have a negative impact on designer productivity.

The technology of CAD imposes requirements that can lead to increased complexity in the organization of the design effort. In contrast to the relatively simple line management that previously sufficed for engineering design organizations, CAD requires the involvement of a variety of specialists in addition to designers—computer specialists, computer maintenance personnel, software engineers, programmers, system support consultants, training specialists, liaison personnel, special study committees, and others.

As a consequence, almost any struc-. The number and complexity of linkages among individuals and groups are likely to be greater simply because of the large number of interdependencies. The aerospace designers interviewed and surveyed reported many continuing difficulties of an intraorganizational nature that affected their design effectiveness, which suggests that these issues are not easily resolved.

These findings are consistent with those reported in Chapter 4 , which examines organizational complexity and inertia relative to the introduction of automation into office work. The CAD workstation provides the designer with direct access to a variety of computer-based tools with which to perform design tasks.

A tool consists of some combination of hardware and software that performs a function for the designer. The principal components are hardware display and control devices, through which the designer interacts with the computer system, and software application programs that perform various functions at the command of the designer. The central role of these tools in CAD suggests that individual productivity can be facilitated or inhibited by the degree of compatibility between the designer and the tools provided.

In the aerospace company, there were wide-ranging differences among the principal CAD tools in terms of their perceived effectiveness. Some were rated highly positioning objects in three dimensions and checking the fit of parts , but others were given very low ratings dimensioning, performing calculations, and filling and shading.

The verbatim comments that accompanied the overall ratings of the CAD tools indicate that the ratings were based primarily on the ease and consistency with which the tools could be used. The highly rated tools were characterized by comments such as ''smooth and reliable response to control actions," "consistent presentation of geometry," and "ease and clarity in locating contacting surfaces and analyzing clearances between surfaces. Closely linked to the usability of the system is the effectiveness of the support provided to the designer.

CAM can be used to automate a factory through systems such as real-time control and robotics. Because the manufacturing processes in a CAM system is computer controlled, a high degree of precision can be achieved that is not possible with a human interface. The CAM system, for example, sets the tool path and executes precision machine operations based on the imported design. Some CAM systems bring in additional automation by keeping track of materials and automating the ordering process, as well as some maintenance tasks such as tool replacement.