STYLING AND DESIGNING

BUS INTERIORS

CAD:- Computer Aided Design

Computer aided design is related to design activity which is needed to be well-managed and counted all acts that are responsible to the functionality of the product and its success underdevelopment .A products means a single component, which is functional in itself like a wrench or an assembly of a large number of components all of which will contribute to the functioning of the part such as an Automobile engine.The complexity of the design process certainly increases with the number and diversity of components present in the final part.

Since there are large number of influencing factors,it is impossible to specify a design procedure for each component.In this we are interested in developing some common guidelines and steps that are needed to proceed for a successful product design and manufacture.The various faculties that are responsible for a successful product can be classifies under two headings as follows:

CAM:- Computer Aided Manufacturing

From the manufacturing activities Like Mass production,Batch production and Job shop production where does CAM find applicability?Practically in all the ranges of production.
However,its use is more important in second and third category by virtue of the added amount of data processing needed in these.In particular,the present trend of large varieties and lower product lives requires that the total manufacturing Lead times be smaller.The only way to ensure this is to improve manufacturing methods and CAM proves indispensable in this regard.

Avantages of Using CAM

1) Greater design freedom : Any changes that are required in design can be incorporated at any design stage without worrying about any delays,since there would be any in an integrated CAM environment.
2) Increased productivity :In view of the fact that the total manufacturing activity is completely organized through the computer,it would be possible to increase the productivity of the plant.
3) Greater Operating flexibility: CAM enhances the flexibility in manufacturing methods and changing of product lines.
4) Shorter lead time: Lead times in manufacturing would be greatly reduced.
5) Improved reliability:In view of the better manufacturing methods and controls at the manufacturing stage,the products thus manufactured as well as of the manufacturing system would be highly reliable.
6) Reduced maintenance :Since most of the components of a CAM system would include integrated diagnostics and monitoring facilities,they would require less maintenance compared to the conventional manufacturing methods.
7) Reduced Scrap and rework: Because of the CNC machines used in production,and the part programs being made by the stored geometry from the design stage,the scrap level would be reduced to the minimum possible and almost no rework would be necessary.
8) Better Management control : As discussed above,since all the information and controlling functions are attempted with the help of the computer,a better management control on the manufacturing activity is possible.

CAE:- Computer Aided Engineering

The kind of analysis facilities that are required to be carried on the product models being generated should be considered.The simplest kind to the most sophisticated features may be available under this category.The simplest facilities may be calculating perimeter,area,volume,mass,centre of gravity,moment of inertia,radius of gyration,etc.

Finite Element Analysis
Besides these simple featureas of analysis,a general-purpose analysis that is normally carried is the Finite Element Analysis (FEA)the geometric model created as above could be conveniently passed on to the FEM though an intermediate processor called a FiniteElement Modeller (FEM),which converts the geometric data in to the finite element mesh and calculates al the data required for the analysis and then transmits it to the FEA program.

Rapid Prototyping

Physical model that directly represents the component is much better than pure computer visualization .Real component helps in obtaining the necessary information for manufacturing information generation.Rapid prototyping is a means through which the product geometry as modelled in the earlier stages is directly utilized to get the physical shape of the component.

RP refers to a variety of spicialized equipment,software and material capable by using 3D CAD design data (as well as 3D scan data) input to directly fabricate geometrically complex objects.Rapid prototyping technologies generally based upon a layered manufacturing concept.In this method, a 3D model of the object in CAD is first decomposed in to cross-sectional layer representations of very small thickness.The system then generates trajectories for the material to be added in each layer by the RP machine.The sacrifical supporting layer from above is then deposited and fused to the previous layer using one of the many available deposition and fusion technologies.

The Basic methodology for all current RP Technique Can Be Summarized as follows:

" A CAD model is constructed ad then converted to STL (standard triangular language )format:
" The RP device processes the STL file by creating sliced layeres of the model.The resolution of future model diredtly depends on quality of the layers or,since all layers must have identical thickness,on the layer's thichness.
" The first layer of the physical model is created,the model I then lowered by the one layer thichness,and the process is repeated until completion of the model;
" The model and any supports are removed;the surface of the model is then finished and cleaned.

Machining also can be considered as rapid prototyping,though it requires custom fixturing and has inherent geometric limitations.Still,machining can be effective in many rapid prototyping applications