Contents Introduction: ...... 2
Relationship Between Product Design and CAD: ...... 3
Applications of Computer Aided Design(CAD) in Product Design: ...... 5
Engineering Analysis ...... 5
CAD System Hardware: ...... 6
Different CAD Software: ...... 8
Major Areas of Application: ...... 9
Benefits Of Application of CAD in Product Design: ...... 11
Conclusion: ...... 12
Glossary: ...... 12
References: ...... 12
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Application of CAD Software in Product Design
Introduction: Product design serves an important function in the production system. It helps determine the eventual commercial success of a product; it determines how the production system should be created, and exactly what equipment should be bought; and it determines how easily, and how cheaply, the product can be manufactured. The manufacturing support system contains procedures and systems used to manage production and solve the technical and logistical problems associated with designing the products, planning the processes, ordering the materials, controlling work-in-process as it moves through the plant and delivering products to customers. Product design and its associated use of computer-aided design/computer-aided manufacturing (CAD/CAM) systems, represents one of the most important aspects of the manufacturing support system.
Figure: Components of CAD
In CAD/CAM, both design and manufacturing are tightly integrated into a continuum of activities. Continuing the integration, there are Computer Integrated Manufacturing (CIM), which includes CAD/CAM, but also extends to embrace the business functions of a manufacturing firm.
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Relationship Between Product Design and CAD: Product design is of critical importance to the production system. It contributes more than any other attribute to the overall design and operation of the production system, and its success determines whether the production system will be fit for use in making products over the long term.
The general process of design may be seen as an iterative process with six key phases. They are given below:
1. Recognition of need: This involves the realization that a problem or need exists that may be solved by design. This may mean identifying some deficiency in a current machine design by an engineer, or perceiving some new product opportunity by a salesperson.
2. Problem definition: This involves a thorough specification of the item to be designed. Specifications include physical characteristics, function, cost, quality, and operating performance.
3. Synthesis: Synthesis refers to the bundling of information that occurs after problem definition, and concurrently during analysis, and after re-analysis.
4. Analysis and optimization: Analysis is concerned with the investigation of design specification information, and the optimization of this information, as well as a synthesis of new information, as required.
5. Evaluation: Evaluation involves measuring the design against the specifications established in the problem definition phase. This evaluation may require the building and testing of prototype models to assess operative performance metrics for the proposed design. This may lead to the re-design of certain or all elements.
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Figure: Product Design Process and Computer Aided Design
6. Presentation: This is the final phase, where the design is documented by means of drawings, material specifications, assembly lists, and so on. Documentation means that the design database is created.
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Applications of Computer Aided Design(CAD) in Product Design: CAD is any design activity involves the effective use of computers to create, modify, analyze, or document an engineering design. It is most commonly associated with the use of an interactive computer graphics system, referred to as a CAD system.
The CAD system can facilitate four of the design phases as shown in the figure. They are:
Geometric modeling
Geometric modeling is a special use of CAD data to create a mathematical description of the geometry of an object. The geometric model, which contains the mathematical description, is contained in the computer memory; and the CAD system. The operator can create new geometric models from basic building blocks available in the system. These capabilities allow the operator to interrogate existing product models, and create new variations on existing products to cater for a wide variety of needs. There are two types of geometric models used in CAD; these are:
Two-dimensional modeling Three-dimensional modeling.
Geometric models in CAD can also be classified as wire-frame models, or solid models.
Figure: Wire Frame model Figure: Solid model
Engineering Analysis Once a design has been developed, it must then be subjected to engineering analysis. This engineering analysis may include various tests, depending on the product, but may include: stress-strain calculations, heat transfer analysis, or dynamic simulation. These analyses tend to be quite complex, which has led to the development of computer-aided engineering (CAE) software packages, so that complicated engineering analysis may be performed by computer. CAE packages in common use with CAD systems include:
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Mass properties analysis Interference checking Tolerance analysis Finite element analysis Kinematic and dynamic analysis Discrete-event simulation
Design Evaluation and Review
Following comprehensive engineering analysis, the proposed design must be evaluated and reviewed for consistency. Some CAD features that are helpful in evaluating and reviewing a proposed design include:
Automatic dimensioning Error checking Animation of discrete-event simulation solutions Plant layout design scores
Automated Drafting:
CAD may also be used as a presentation application, in that the CAD system can produce highly accurate engineering drawings quickly and conveniently, and also provide associated documentation as necessary. It is estimated that a CAD system increases productivity in the drafting function by about fivefold over manual preparation of drawings.
CAD System Hardware: Hardware is used in CAD systems .The relationship between the components are:
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Table: Hardware used in CAD systems
Hardware Description Design workstations This has the following functions: (1) communication with the computer’s central processing unit; (2) continuously generate a graphic image; (3) provide digital descriptions of the image; (4) translate user commands into operating functions; and (5) facilitate interaction between the user and the system. CAD workstation design has an important influence on the convenience, productivity, and quality of user’s output. The workstation consists of a display terminal and a set of user input devices, with which the user interacts with geometric model via: entering alphanumeric data; entering system commands to perform various graphics operations; and by controlling cursor position on the display screen. Digital computer This uses a high-speed central processing unit to process CAD operations. There are several CAD system configurations, such as host and terminal; engineering workstation; and a CAD system based upon a personal computer Output devices These include plotters and printers, which generate the output from the CAD system. Plotters include: pen plotters, which are x-y plotters of various type, used to produce high accuracy line drawings; and electrostatic plotters, which are based upon the same principal as photocopying, and produce lower quality drawings. Printers used include inkjet printers, where drawings are produced by high- speed jets Secondary Storage This includes various storage devices attached to the CAD system to store programs and data files. The storage mediums used can include: magnetic discs, magnetic tape, floppy discs, external hard-drives etc.
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Different CAD Software: There are many CAD vendors for the various applications. The following table summarizes some of them:
Mechanical CAD Software · Alias/Wavefront Surface Studio · Applicon Bravo · Autodesk AutoCAD · Autodesk Mechanical Desktop · Baystate Technologies Cadkey · Bentley Systems MicroStation · CoCreate SolidDesigner · CoCreate ME10 · Dassault Systemes CATIA · IBM CATIA · Matra Datavision Euclid3 · MCS Anvil Express · Micro CADAM Helix · PTC Pro/DESKTOP · PTC Pro/ENGINEER · SDRC Artisan Series · SDRC I-DEAS Master Series · SDRC Imageware Surfacer · SofTech (Adra) CADRA · SolidWorks · Think3 (CAD.LAB) Eureka Gold · Unigraphics Solutions Solid Edge · Unigraphics Solutions Unigraphics · Varimetrix VX Modeling · Visio IntelliCAD · Visionary Design IronCAD Mechanical CAE (Analysis) Softwares: Algor Algor ANSYS DesignSpace MacNeal Schwendler (MSC) NASTRAN, Etc. MARC Mentat & MARC Mechanical Dynamics ADAMS LMS CADSI DADS PTC Mechanica SRAC COSMOS/M AEC(Architecture, Engineering & · Autodesk Architectural Desktop Construction) CAD Software · Cadcentre PEGS · IBM CATIA/CADAM · Intelligent Computer Solutions OpenPlant
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· Intergraph Imagineer CAD Kernels · Matra Datavision CAS.CADE · Ricoh Designbase · Spatial Technology ACIS · Unigraphics Solutions Parasolid · XOX Shapes CAD Verification Tools · ITI CAD/IQ · Prescient DesignQA Electrical CAD Vendors · Cadence Alta · Mentor Graphics Inter-Connectix Clothing and Shoes Industry · Lectra Systemes - Lectra (clothing & shoes) Rapid Prototype · 3d Systems - SLA · Cubital - Solider
Major Areas of Application: CAD has been applied to many industrial sectors.
Mechanical Sector: The mechanical sector is the largest user of CAD systems. Applications are usually coupled with manufacturing, forming a CAD/CAM system. The applications cover all types of manufacturing operations, such as milling (2 ½, 3 – 5 axis of control),turning, wire EDM, punching, etc. The user can test the part program on screen prior to the transfer to the machine tool and accomplish collision detection, undercuts, etc. Most of the systems have a post processor integrated to communicate with the machine tools.
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Architecture, Engineering & Construction: The AEC sector is the second largest application areas of CAD systems. Applications range from single a simple building design, to large scale projects, interior design, static and dynamic analysis, etc. These applications are beyond the scope of this report. A number of large projects examples are shown in Figure:
Electronics Sector: The electronics engineering is the third largest application. The computer performs all IC designs. It is the complexity of the designs that imposes the usage of CAD systems. Current systems also include in their software a number of designs in order to offer some assistance to the users for their new designs.
Apparel Industry: The apparel industry is also a large user. The number of systems on offer is limited. A small number of companies are offering systems for the apparel sector worldwide, while on a national base there is a number of companies offering such systems. Systems for clothing are rather expensive, because they are using specialized equipment, such as large plotters, cutters for patterns, and automatic machines for cutting the fabric. Their application ranges from fashion design to manufacturing. The largest usage of the systems is for pattern design and lay planning, where most of the savings are achieved. It is absolutely necessary today
Page | 10 for all companies subcontracting a large supplier to be able to handle electronic data (pattern designs).
Benefits Of Application of CAD in Product Design: CAD provides the following benefits:
Increased design productivity—CAD reduces the time required to conceptualize and physically draw product designs;
Increased available geometric forms in the design—CAD allows the design to choose from a range of geometrical shapes that would normally be outside the manual drawing process.
Improved quality of the design—the use of a CAD system with appropriate hardware and software capabilities permits the designer to do a more complete engineering analysis and to consider a larger number and variety of design alternatives. The quality of the resulting design is thereby improved.
Improved design documentation—the output of a CAD system results in better documentation of the design than what is usually seen as practical in manual drafting.
Creation of a manufacturing database—by creating product design documentation, much of the required database to manufacture the product is also created.
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Design standardization—design rules can be included in CAD software to encourage the designer to utilize company-specified models for certain design features.
Conclusion: In this assignment, the discussion and definition of product design and CAD are given, where an analysis of the design process and the actual application of computer-aided design principles are highlighted. CAD system hardware is reviewed and different CAD Software is shown. After finding huge application areas of CAD in Product Design, we can say CAD software certainly give Product design a whole new dimension.
Glossary: AEC- Architecture, Engineering and Construction
CAD- Computer Aided Design
CAE- Computer Aided Engineering
CPU- Central Processing Unit
PD- Product Design
References: 1. Roy L. Wysack, «Effective CAD Mangement – A Manger’s Guide», CAD/CAM
Publishing, 1985.
2. H. Zeid, «CAD/CAM Theory and Practice», McGraw Hill, 1990.10.
3. The CAD Report, CAD/CAM Publishing Inc., Vol.19, No 2, 1999.
4. En.wikipedia.com
5. www.google.com
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