CAD CAM SYSTEM Evaluation Criteria to select the Software
- 1. CAD/CAM System Evaluation Criteria Prof. R.B.Chadge
- 2. Introduction • These lists typically begin with cost criteria and end with simple models or benchmarks chosen to test system performance and capabilities. • Some other factor such as compatibility requirements with in-house existing computers, perspective departments that plan to use the system and credibility of CAD/CAM system suppliers. • Selection guidelines vary from one organization to another.
- 3. Criteria for Evaluation • System consideration • Geometric modeling capabilities • Design documentation • Application
- 4. System Consideration • Hardware • Software • Maintenance • Vendor Support and Services
- 5. System Consideration Hardware • The open architecture of the hardware is crucial to system expandability and future networking needs. • The types of peripherals supported by the system are also important to the documentation phase of design work performed by the system. • Two popular hardware configuration are disked and diskless workstations. • In the former, each workstation has enough local disk space and memory to be stand alone.
- 6. System Consideration Hardware • In the latter, each workstation is connected to a central computer, called the server. • Server has enough large disk and memory to store users files and application program as well as executing these programs. • In diskless configuration, it is recommended that each workstation has enough swapping disk to avoid degrading the response time.
- 7. System Consideration Software • Three major contributing factors are A)The type of Operating system B)The type of user interface (Syntax) and C) The quality of documentation. A) Operating system • The first factor is important to perform CAE work which typically involves running third party software. • Psychologically easier to teach new CAD/CAM software user on standard operating system.
- 8. System Consideration Software • Standard systems also become important when in house software developments are needed. B) User Interface • In evaluating the user interface, care should be given to whether the interface can accommodate both experienced and new users.
- 9. System Consideration Software C) Quality of Documentation • It is the easiest criterion to evaluate simply by reading the relevant manuals. • The most important issue to investigate is how easy it is to use the documentation and • There are online help functions are available or not.
- 10. System Consideration Maintenance • Repair of hardware components and software updates comprise the majority of typical maintenance contracts. • The annual cost of these contracts is substantial (about 5 to 10% of the initial system cost) and should be considered in deciding on the cost of a system in addition to the initial capital investment.
- 11. System Consideration Vendor Support and Services • It includes training, field services and technical support. • Most vendors provide training courses, sometimes on-site if necessary. • The timely response of the vendor response centers to customers technical questions is important.
- 12. Geometric Modeling Capabilities • Representation Techniques • Coordinate systems and inputs • Modeling entities • Geometric editing and manipulation • Graphics standards support
- 13. Geometric Modeling Capabilities Representation Techniques • Geometric modeling module is a heart of the CAD/CAM system. • Wireframe, surface and solids are the tree types of modeling available. • It is important to consider the various entities supported by each representation. • The integration between the various representations and the applications they support is essential.
- 14. Coordinate Systems and Inputs • In order to provide flexibility to designer for generating geometric models, various types of coordinate systems and coordinate inputs should be provided. • The ability of the designer to define the proper planes of constructions is valuable to create faces that are not parallel to the standard orthogonal planes (front, top, right). Geometric Modeling Capabilities
- 15. Geometric Modeling Capabilities Coordinate Systems and Inputs • Coordinate inputs define in the form of Cartesian (x, y, z), Cylindrical (r, ɵ, z) and Spherical (ɵ, ɸ, z).
- 16. Geometric Modeling Capabilities Modeling Entities • System supports representation schemes is not enough. • It is important to know the specific entities provided by the schemes. • The ease to generate, verify and edit these entities should be considered during evaluation.
- 17. Geometric Modeling Capabilities Geometric Editing and Manipulation • It is essential to ensure that these geometric functions exist for the three types of representation. • Editing function include intersection, trimming and projection. • Manipulation include translation, scaling, rotation, copy , mirror, offset and changing attributes.
- 18. Geometric Modeling Capabilities Graphics Standards Support • In geometric models databases are to be transferred from one system to another, both systems must support exchange standards. • These standards are valuable if various systems exist in one organization or if design models are shipped to outside vendors for various reasons such as tools, jigs and fixture design or generating NC part programs.
- 19. Geometric Modeling Capabilities Graphics Standards Support • Graphics standards may introduce inconsistencies and errors into CAD/CAM databases.
- 20. Design Documentation Generation of Engineering Drawing • After a geometric model is created, standard drafting practices are usually applied to it to generate the engineering drawing or the blueprint. • Various view are generated in the proper drawing layout. • Then dimensions are added, hidden lines are eliminated, tolerances are specified, general notes and labels are added, etc.
- 21. Design Documentation • These activities are time-consuming. • To generate an engineering drawing, it typically takes as much as two or three times as long as it takes to generate the geometric model.
- 22. Applications • Assemblies or Model Merging • Design Applications • Manufacturing Applications • Programming Languages Supported