A Study On Computer Aided Design

Before the 1070s, nearly every drawing produced in the world done with pencil or ink on paper. Minor changes require erasing and redrawing while major changes often meant recreating the drawing from the scratch. A change in a drawing will affect the other documents and all of these changes and recognition are done manually which is time consuming (iBM.com, 2003). The introduction of Computer Aided Design (CAD) then makes a change in the way of producing design.

CAD is a software application which uses the computer technology in the process of design and design-documentation. Basically, CAD software is used to design curves and figures in two-dimensional (2D) space, curves, surfaces and solids in three-dimensional (3D) objects. CAD software enables the user to produce better streamlining design, drafting, and documentation and facilitate manufacturing process. It provides output in the form of electronic files and allows the users to get printing copy.

CAD software is often used in construction, manufacturing and other industries because it can bring economy to the processes by providing convenience in conveying information in technical and engineering drawings. Examples of information which can be conveyed are materials, processes, dimensions and tolerance. The software helps to produce drafting and design for all types of buildings such as residential houses, hospitals and factories. Besides, the software is also used throughout the engineering process to produce conceptual design and layout for the products and define the strength and dynamic analysis of manufacturing components.

There are many CAD software producers such as AutoCAD, Autodesk Inventor, Pro-E Wildfire, Catia and many.

CAD ORIGIN/ TERMINOLOGY

There are many essential synonymous terms in CAD software. It is sometimes translated as ‘computer-assisted’, ‘computer-aided drafting’, or a similar phrase. CADD (Computer Aided Design and Drafting) and CAM (Computer Aided Manufacturing) are other related acronyms. All of these terms have subtle differences in meaning and each is used for different purpose.

CAD HISTORY

Dr Patrick J. Hanratty developed the first commercial numerical-control programming system in the year 1957. He had greatly contributed to the field of CAD design and manufacturing and he was known as ‘the Father of CAD’.

In year 1960, Ivan Sutherland produced a project called SKETCHPAD as the first step to CAD industry. SKETCHPAD allowed the designer to interact with computer graphically where the design can be fed into the computer by using a light pen to draw on a monitor. Thus, making it as an indispensable feature of modern CAD software.

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The first commercial applications of CAD were in large companies in the automotive and aerospace industries as well as in electronics. This was due to only large corporations could afford the computers capable of performing the calculations. In year 1964, Dr Patrick J. Hanratty had utilised Design Augmented by Computer (DAC-1) in his company projects. In year 1971, UNISURF was developed by Pierre Bézier at Renault. It was a pioneering surface CAD system for car body design and tooling. The founding of Manufacturing and Consulting Services Inc. (MSC) in year 1971 by Dr Patrick J. Hanratty enhanced the development of CAD. He then supplied the codes to many companies such as Control Data, Autotrol, Garber, Calma and many.

The application of CAD expanded gradually when computer became affordable. The development of CAD software for personal desktop computers was the momentum for almost universal application in all areas of construction.

Key points in the 1960s and 1970s such as IBM, Intergraph and Intergraph IGDS became the foundation of CAD systems. Since then, the implementation of CAD had evolved dramatically. 2D graphic was design with CAD software initially in the 1970s and limited to producing drawings similar to hand-drafted drawings. Variety applications of CAD were allowed when programming and computer hardware became advanced.

In year 1982, Autodesk was founded by John Walker which then led to the 2D system AutoCAD. In year 1988, Pro/Engineer was released and required greater usages of feature based modelling methods. The development of graphics engines ShapeData and ACIS at the end of the 1980s inspired by the work of Ian Braid. The inspiration then led to the release of SolidWorks in year 1995 and SolidEdge in year 1996.

Today, in 21st century, there are many CAD software products in the market. The famous CAD software producers are Autodesk, PTC, UGS Corp and many. Generally, the package of CAD software can be classified into 3 types, there are 2D drafting systems, mid-range 3D solid feature modellers and high-end 3D hybrid systems.

CAD DEVELOPMENT IN MALAYSIA

In Malaysia, CAD software has been on the sell since the 1980s. In the mid 1990s, the applications of sophisticated CAD tools with 3D modelling and coloured graphics enhancements had become more common. Since then, the usage of CAD has impacted the professional practice, education and the research associated with architecture tremendously.

In the present time, CAD software including CAM is now widely accepted and used throughout the industry. The technology moves from costly workstations to off-the-shelf computers. 3D modelling has become a norm and it can be found even in applications for the wider industry such as house furnishing and garden planning.

As the usage of CAD has become part and parcel of the daily running of architecture firms, higher-learning institutions such as universities and colleges have produced great efforts in preparing the built environment market with workforce that is equipped with the essential skills and ability to operate CAD.

CAD APPLICATIONS

CAD is used to design, develop and optimize products, which can be goods used by end consumers or intermediate goods used in other products. For example, buildings, mechanical and engineering tools, vehicle and transportation and many other product designs.

In the field of engineering, CAD allows design and drafting of tools and machinery which are used in the manufacture components. Besides, detailed engineering of 3D models and 2D drawings of physical components can be generated easily by applying CAD.

In the field of building architecture, CAD has reduced the need for manual drawing. CAD helps to generate all particulars of a building such as floor plans, sections, elevations, perspectives views and model renderings in a shorter time. The software allows drafting and design of all types of buildings.

Besides designing, developing and optimizing products in building and engineering, CAD is also used for business purpose such as the followings:

Testing on Conceptual Products

CAD eliminates the need to test all of the product design physically. Instead of conducting physically testing, the developers can run virtual tests using CAD which can simulate the same condition. The application of virtual tests is often adopted in the aeronautical company which its testing can be ruinously time consuming and expensive.

Idea Generation

CAD allows flexible process of idea generation when the limiting factor of prototype manufacture is removed. The enterprises, both employees and potential customers are exposed to more open and new ideas and suggestions. The suggestions for new products then can be tested quickly at a lower cost.

Augmentation

CAD allows slight improvement on new product designs instantly. It is useful in investigating possible improvements to existing products.

Market Testing

CAD allows earlier process of market testing because virtual new products can be presented more quickly than physical prototypes and feedback can be obtained instantly.

CAD can also be applied in the field of medical to manipulate medical images such as digital x-ray image (DICOM). The application of CAD in the presentation of medical images is still new compared to CAD widely used in the fields that involve with designing of the manufacturing industry products and construction field.

CAD PRINCIPAL

CAD is one of the many tools most used by engineers and designers.

3D Wire Frame is an extension of 2D drafting. Basically, it possesses similar fashion to the 2D system. Its final product does not have mass properties. Besides, there is no feature directly added to it such as holes.

3D Dumb Solids possesses similar fashion to the way of creating the real world object. This technology has been incorporate into programs such as AutoCAD and Cadkey 19. The principal provides draft views which can be easily generated from the models. However, the changes can only be done by deleting the object or feature and start over. Besides, its assemblies do not include tools which allow motion.

3D Parametric solid modeliling allows the operator to use what is referred to as ‘design intent’. Any future modifications to the design will depend on the original part. It may be simple, difficult or nearly impossible. This technology has been incorporate into programs such as Alibre Design, TopSolid, SolidWorks and Solid Edge.

KNOWLEDGE AND SKILL COMPETENCIES FOR CAD

According to Duan (2006) study, CAD and design engineering users require 7 categories of skills and knowledge as the followings:

General knowledge and skills

English writing and speaking

Communication

Critical thinking

Problem solving

Mathematics and science skills.

Interpersonal skills

Basic drafting knowledge and skills

Basic drafting

Descriptive geometry

Technical standards

Coordinate systems

Multiview drawings

Isometric drawings

Geometric dimensioning and tolerance

Basic mechanical drafting

Basic architectural drafting

Basic civil drafting

Computer knowledge and skills

Computer fundamentals

Computer file management

Word processing

Computer software

Spreadsheets

Basic application of internet

Basic programming

CAD knowledge and skills

Major CAD software

CAD 2D drawings

CAD 3D modelling

Basic CAD LISP Programming

CAD design project

Custimization of CAD program

Basic engineering analysis and technical knowledge and skills

Special knowledge and skills

Design application and practices

Special projects in the field

Marketing and sales

Basic knowledge of laws

Troubleshooting skills

Teamwork

Leadership skills

ADVANTAGES OF CAD

CAD software offers several advantages which attracts many industry players. Basically, it offers benefits which then can lead to time and cost saving. Both cost and time saving are important especially in the world of business because in the view of commercial man, time is money.

First of all, the software has become an important technology in ensuring lower product development costs. Before the 1070s, nearly every drawing produced in the world done with pencil or ink on paper and any change requires erasing and redrawing which will produce waste. CAD software enables the designers to develop their work on screen and allows future editing. Thus, it brings benefits in cost saving instead of redrawing due to minor changes. Besides, the software also ensures short design cycle as it eliminates the needs to redraw when minor changes happen, it brings benefits in time saving.

Both cost and time saving in product development can also be achieved by eliminating the need to test all of the product design physically. Instead of conducting physically testing, the developers can run virtual tests using CAD which can simulate the same condition. The application of virtual tests is often adopted in the aeronautical company which its testing can be ruinously time consuming and expensive.

Cost saving can be achieved by reducing the number of designers. By using CAD, the professional designers can do the designing work faster and eliminate the need of additional designers. Besides, cost saving also takes place when CAD software offers better and standardised drawings which then facilitate better communications.

Moreover, CAD allows quickly and easy design alteration which also lead to faster product development. Faster product development then will lead to increase in productivity of the designer. The software allows understanding on how the actual product works by giving animation to the product so that immediately modifications can be made if required. CAD software helps the designer in synthesizing, analysing and documenting the design. Thus, the productivity of the designer can be improved due to fast designing, low designing cost and shorter completion times.

In addition, saving in time and cost does not affect the quality of the design. In fact, CAD can improve the design quality because large number of tools is offered by the software which assists investigation and analysis of the proposed design. Beside, CAD also offers greater accuracy and errors are reduced to give a much better design. This better design can help to carry out faster manufacturing and reduce wastage due to faulty design.

DISADVANTAGES OF CAD

Although most of the users understand on the advantages brought by CAD, in the mean time, it comes with several disadvantages that the engineer or entrepreneur must understand. These advantages may affect the approach that getting a product on the market.

The application of CAD software requires training among the users. This will then costs additional money in the staff training.

Besides, its application requires expensive start up costs including hardware, software and training. Computer technology used in CAD is expensive to implement and support the software. Besides, the technology is not constant as new hardware and software programs constantly come on the market and therefore, the users need to keep up with these changes for compatibility reasons.

Risk of technology failure must be taken into consideration when implementing CAD as computer used may break down. It then affects the progress of product development which is not favoured in a strict production schedule. The risk is highest when the company relies on assembly-line structure as failure will affect all points of production instead of an isolated production area. Besides, when there break down in computer, all the data saved including CAD copy will be lost.

SUMMARY

Before the 1070s, all of the design and drawings are produced manually which is time consuming. Thus, the introduction of Computer Aided Design (CAD) has made a change in the way of producing design.

CAD is a software application which uses the computer technology in the process of design to produce two-dimensional (2D) space, curves, surfaces and solids in three-dimensional (3D) objects. It is often used in construction, manufacturing and other industries such as the engineering process to produce conceptual design and layout for the products and define the strength and dynamic analysis of manufacturing components.

CAD brings advantages to the users, in the mean time, it also brings limitation or draw back. Basically, cost and time saving are the main advantages as design and drawings can be produced faster than manually. However, when there is a technology failure especially computer, it will affect the production line and cause dalay.

Therefore, wise decision must be made when adopting CAD in product development and it must take into consideration of factors such as time and cost of the technology transfer as well as the expertise available.