Computer Aided Design

Acknowledgments

Special thanks and gratitude is given to —- who helped me with his valuable guidance. I am also thankful the numerous law courts and drug court practitioners who helped during this study and responded to the survey in a timely manner to make this study a success.. My thanks will also be extended to my family including Dad, Mom and —–, my youngest brother for their kind and invaluable support during the whole project.

ABSTRACT 

This paper intends to analyze Computer design from the view point of conceptual design, while stressing the limitations and weak points. Solutions are also proposed to improve product life cycle. Moreover the future developments are also forecasted based on the systems evolution.

INTRODUCTION 

The industry for product life cycle development has been radically altered since the inception of Computer aided engineering (CAE) applications for the purpose of virtual prototyping. Moreover the low cost of the Computer aided engineering (CAE) applications have allowed easier access to the small industries as well. With the evolution of CAE, a large number of simulations can be performed within short intervals of time for the initial phases of product life cycle development cycles. However, this advantages also posses certain drawbacks – a huge number of solutions can be given for computational tests without performing any  checks on their performance and efficiency.

As a result, with the evolution of Computer design systems, focus can now be laid upon the design phase, modeling, CAE and CAD integration phases and other application protocols. CAD offers a number of new functionalities which allow the programmers to get alternative solutions rather than analyzing and developing new ideas, (Mandorli, 1997). As a result, very often a new product borrows the architecture from old works and some parts of the new product are limited by user modeling skills: both these restrictions added to psychological inertia noticeably decrease the originality potential of the designer.

As rightly quoted by Domb 2000, “Ease of usage produces lack of knowledge”, therefore, the evolution of Computer aided design systems has become an efficient way to foresee the subsequent step of design software tools in order to raise the speed toward the future.

BACKGROUND OF CAD SYSTEMS 

The first three dimensional CAD systems were evolved during the 1970’s. The first 3D CAD systems appeared in the early 1970’s. Initially the use geometry representation was with the help of wire frames, subsequently, Hidden Line Removal algorithms came up which made use of 2D CAD with the help of electronic drawing machines. The next generation gave the concept of 3D CAD, with the further addition of canvas, frames, texts, colors, objects and point features, (AuEna, 2002).

The appropriate pace in the direction of 3D solid CAD modeling was given by CSG representation. CSG is termed as Computer Scenographics, a process which helps to create the tools used for graphic designing with the help of computer design. This is an iterative process related to the design activity. Further enhancement of the 3D CAD systems with the introduction of Boundary representation (B-rep) method, offered the use of complex shaped figures even with less efforts and computer skills.

With regards to the client interface and comfort, the introduction of feature based modeling systems in the 3D CAD systems have given a more technology oriented approach, which allows the geometric entities to be grouped in various categories depending upon their technological meaning of the shape element.

CAD ANALYSIS  

Programmers directly working in the CAD environment often find it difficult to propose new product innovations and solutions. On the contrary, there exist quite a few restrictions on the individual creativeness skills seeing as the existing interface is in tune with the detail design phase.

Feature-based modeling tries to take into account technological matters of parts geometry, but no relevance is given to the process of shape conception. First of all, the designer has to face product design distinguishing between improving parts shape design and assembly design as they were two separate entities, since parts and assemblies are managed in two different environments. In facts, from the conceptual design point of view, the top down modeling approach is not sufficient to overcome this dramatic constrain; besides, during the first stages of product definition designers don’t know how many parts are going to be defined and the unique goal should be accomplishing functions. (Mann,1999).

The actuality of a twofold modeling situation is owing to the simplicity of modeling necessities; in addition, it permits the administration of multifaceted mechanical system in the course of a hierarchy of assemblies, sub-assemblies, parts and features. On the other hand this explanation is admittable only when the system to be embodied is by now, even if approximately, clear. In addition, it augments the mental inaction of technicians and their unwillingness to alterations since, for example, a long series of operations must be performed to segment a component into different parts easier to manufacture, (Mandorli, 1997).

When analyzing the parts shape subject, the original CAD offers a number of modeling functions which are comparatively easier to use and implement, requiring affordable computer resources. In order to evaluate the existing CAD systems, it is helpful to merge the dilemma definition tools by Ideation (Innovation WorkBench) and Invention Machine (Tech Optimizer). The Ideation (Innovation WorkBench) allows the definition of a model of the actual situation in terms of cause-effect relationships, to be automatically translated into basic directions of innovation; the latter has been used to build a functional model of CAD modules and features in order to rank their efficiency according to the Value Analysis principles. (Cascini, 2001).

The diagram shown below depicts the aforesaid condition- figure 1.

Figure 1. Function relationship model – CAD system

The next figure tried to make an analysis of the limitations and the trends that should be followed in order to improve the CAD systems. If the CAD system needs to be analyzed then all the factors of functionalities, benefits, problems and costs need to be taken into consideration. The value of any involved element in the CAD system may be calculated as .

(F)/ P+C, ———————– (1)

where F = functionality

          P= Weight of the problem

          C= Cost

The functionality element F is estimated by including the quantity of practical functions which can be performed by a component, weighted by 1/n, where n is the “minimum distance” of such an action from the product of the functional diagram (i.e. the object of the main function of the system). Weight of the problem – P is defined by the sum of the harmfulness and/or the insufficiency of its function [Arel et al. 2002].

Figure 2. Functional analysis of CAD systems

CAD EVOLUTION

Here is a set of directions that help to evaluate the future steps in CAD evolution and further enhancements.

1. Product design by CAD should not be limited only to improving the design and shape of the product and should not be either influenced by any kind of psychological inertia and different assembly environments, (AuEna, 2002).

2.. Other alternatives should be found out to obtain the ease of modeling without the help “part/assembly separate environment”.

3. Search for other options to improve the shape and design that builds up product innovation techniques and is not influenced by “non flexible part geometry”.
4. Try to avoid the individual modeling functions and offer easy use and implementation of CAD techniques
5. Search for the next transition phase of CAD modeling that will be free of the existing problems encountered.
6. Searching for new alternatives that will enhance the existing assembly design ways and product innovation techniques and are not dependent upon the part/assembly separate environment, (Cascini, 2001).
7. Opt for methods that complex system management in a more effective manner through the CAD systems. 

FUTURE IMPROVEMENTS 

1. Modification of shape and design – first to eliminate the harmful effects brought in the system by application of non flexible geometry and then initiation of shape enhancement characteristics can prove to be the first step towards building an efficient modeling environment that may prove good for geometry preliminary definition, (Mann, 2002).
2. CAD/CAE integration – major advantages can be taken up by integration of CAE techniques with CAD. Usually CAD is until now a subset of CAE and the information flow is one way – from CAD to CAE, therefore, if two ways integration takes place, then better optimization tools can be better implemented both for quality and speed.
3. CAD storming – this pertains to the process of working together on a model to apply deep technical changes and remove the slowness acquired by the moiling activity for the modeling process
4. Relations model- This environment should allow also the definition of any kind of links between the geometric entities, as well as properties and constrains: like that of working volume, mass properties, speeds, interactions etc. 

CONCLUSIONS 

The analysis presented in the paper shows the insufficiency of the existing CAD tools. There are some future improvements recommended that be implied to enhance the suitability of computer-aided design tools for the initial design phases of product development.

REFERENCES 

Abate V., Cascini G., Rissone P., Extracting Technical Knowledge for the Computer-

Aided Design of Adhesively-Bonded Joints, 7th International Conference on Production

Engineering, Design and Control (ASME), Alexandria, Egypt, 13 – 15 February 2001.

AuEna T. Arel, Mikhail Verbitsky, Igor Devoino, and Sergei Ikovenko, TechOptimizer™ Fundamentals, Invention Machine Educational Services, 2002

Cascini G., Corsi C., Rissone P., From CAD to KAD: a design tool for adhesively –

bonded joints with a dynamic knowledge base, 12th ADM International Conference on

Design Tools and Methods in Industrial Engineering, Rimini, Italy, 5-7.9.2001.

Mandorli F. Cugini U., Otto H.E., Kimura F., Modeling with self validation features,

Proceedings of the 1997 4th Symposium on Solid Modeling and Applications, Atlanta,

USA, 1997.

Domb E., Strategic TRIZ and Tactical TRIZ: Using the Technology Evolution Tools,

The TRIZ Journal, January, 2000.

Ikovenko S, Speeding the Innovation Process: How to Improve the Performance of

Engineering Systems, NASA Tech Briefs Short Course, Photonics EAST, 19-22

September 1999.

Mann D., Using S-Curves and Trends of Evolution in R&D Strategy Planning, The

TRIZ Journal, July, 1999.

Mann D., Hands-On Systematic Innovation, Creax, 2002.

Sawaguchi M., Study of Effective New Product Development Activities through

Combinatio n of Patterns of Evolution of Technological Systems and VE, Proceedings of

TRIZCON2001, The Altshuller Institute, March, 2001.

Zlotin B., Zusman A., Directed Evolution Philosphy, Theory and Practice, Ideation

International Inc., 2001.