HISTORY OF CAD
CAD: IT IS REFFERED AS COMPUTER AIDED DESIGN
The CAD software helps engineers and designers in many industries for designing and manufacturing products like aircrafts, ships, cars, bridges, mobile, digital cameras. And it is also often referred as CAD/CAM (COMPUTER AIDED DESIGN/MANUFACTURING).
It is in the 350 BC a mathematician named EUCLID of Alexandria founded the CAD software. "The elements explained many postulates and axioms that are foundations of EUCLIDIAN GEOMATRY". After the Euclid it took 2300 years to get the updated version of the CAD software. As CAD/CAM is the new concept and the usage of this software was linked to computers. 3 decades ago the CAD/CAM was introduced in the sectors of Academic and Government which were released for the public as courses. With the availability of the computers the actual application of CAD/CAM was increased in 1980's. In the initial stages the CAD software was run on the mainframe computers which were a bit expensive so not many engineering companies used CAD software for manufacturing and instead they used to follow conventional methods to design and manufacture. But the increased in the usage of computers and work stations have helped in the development of software by giving sufficient platform to CAD which was initially running by mainframes.
Here is the brief history of the CAD/CAM evaluation in all the decades and all the major developments are mentioned below.
- The research on the computer graphics is done and it is developed.
- In 1962 Ivan Sutherland developed Sketch Pad system.
- CAD/CAM was available in the commercially and was launched by Lockheed.
- Light pen was introduced to design on the Sketch Pad.
- CAD term coined.
- The CAD/CAM was introduced in the sectors like academia and in government.
- Forming of an National Organization of the development for the CAD/CAM
- In the designing process computer graphics were started using.
- Drafting was done by turnkey system.
- The availability of the software's like wireframe and surface modelling.
- And also Finite Element analysis and mass calculation was available.
- Integrated Circuits, verification and NC tape generation were made available.
- For engineering research and development the CAD/CAM was used.
- Algorithms of CAD/CAM and new theories were developed.
- Integration of the CAD/CAM.
- The availability of the solids modelling software.
- Computers and work stations were begun to use for the development of CAD/CAM.
- Concurrent engineering concept was developed.
- Increase in the computers and workstations in the usage of CAD/CAM.
- Hardware and Software development was done.
Principles of cad
Uses and Applications of CAD
The entire product like buildings, bridges, highways and interstates, aircrafts, ships, automobiles, digital cameras, mobile phones, TVs, cloths, shoes and computers are all designed and developed by using CAD software. CAD is used in all the engineering process right from theories designs and layouts, detailed engineering and examination of components to be defined in the manufacturing methods, in the field of Architecture, Industrial designing Engineering, Garden designing, construction of buildings, Automotive Aerospace, Consumer Goods, Machinery, Ship Buildings, Electronic and Electrical appliciences, Software Applications, Apparel and Textile. The CAD software gives numerous results in the many fields, but the result will be in graphically for assement and approvals for the final drawings. For designing the actual drawings the CAD is referred as the exact technical drawing element. Now all the drawings are done in computers by replacing all the drawing boards which is not present now.
Specialized calculation package, pre existing component drawings can give input of designing process. For example Maps, Photos and other Media or any hand drawn sketches created by the designer. The job of the CAD operator is to draw drawings and required specifications so that the required material is used for the manufacturing or to construct as well as estimated cost of the whole project. CAD is also useful in Civil Engineering which helps Engineers to design roads, grading, drainages, mapping and cartography. The survey of the land and the legal boundaries described for the land as given from the geographic and facilities information system. The Architecture and as well as the Interior designing are done with the CAD software which gives the preview to the costumer where he can order the design which he likes for. The furniture, paints, colour can be show in the form of 3D design after the designing is done
CAD IN OVER ALL PRODUCT DEVELOPMENT PROCESS
In the chart it gives the idea and the general design validation and manufacturing process. In each stage it requires specific knowledge and skills, and often requires the use of specific software. The process is divided in to 4 groups
Need of speed:
Without exact need the design process cannot be started. As per the requirements of the work the need of the design can be decided by the market research. Not every time but very rear that the new ideas or innovation for the design process is required.
Before any work to be started there should be research done on the available solutions. Knowing the weakness and strength one should do research on the existing solution and concepts. The research should also cover available parts that can be used for designing. For research to do Internet and Google are very helpful. And there many standardized design in the libraries which help in the research of the design
The design should be at a high level as per the research is done. All the main and important principles and major parts should be specified.
For drafting a design, the designer can use paper or pen. For designing some designers use simple vector program, other designers use simple CAD and other designer use directly from main CAD system for design.
The model in the cad can be designed in 2D or 3D or in both. The model will be created with all the details in the design and for any designing process it is a key part. But even though it is help full it is very time consuming process.
In order to utilize the parts in a model, parts which are developed by the previous team mates can be made use or standard parts can be used. Internet can be used to download the files that represent the parts and by allocating them on either CD ROM or CAD the files can be used as an extension .By accessing the correctness ,predefined parts can be used in the projects there by time and effort can be save. Correlating the parts, exchanging out the equivalent parts and managing the segregated teams from the basic requirements while working on for large projects. The standard part which was put in to project by one team member can be used by the rest.
All the design part are put together by using mating conditions to check the alignments of the two mating bodies which are same and to check the axis of two holes are aligned together. After that the parts are assembled together into a machine or mechanism.
For analysing the 3D model strength and performance special software CAE (COMPUTER AIDED ENGINEERING) is used. Many software tools are used for this task. For this FEM and KINEMATICS are some of the tool and these are built in the software itself.
For manufacturing 3D modelling is used to produce the designs from engineering drawings. According to the design the drawings are sent to respective departments for starting the production. Before the production starts the tolerances of all the designed components are to be checked.
The cam software is used to create a model, optimize use and prepare manufacturing. The Numeric Control code which is generated is executed on lathe or milling machine for manufacturing.
"The critical path methods, Gannt chart and other methods and tools are used by project managers to plan and optimize manufacturing. Project management and ERP system are used".
The designer should create realistic image or animations of the component. This help the costumer read the feed backs of the manufactured components. Major CAD/CAM companies developed and sell tools that which are mentioned in the above process cycle. When the software is complex then it helps in supporting to management, team work, versioning and planning.
BENEFITS OF CAD
The most common applications of the CAD is designing and drafting. The CAD software is used in many Engineering and professional firm for different applications. Here are some of the benefits of using CAD software.
Increase in the Productivity of the design:
The visualization of the final product and analysing the assemblies and subassemblies and their constituent parts can be done by using CAD software. After the product is finished the designer can assemble the parts and can check the exact motion of the component by giving animation. This directly helps the designer to change or do any modifications of the product on the requirement. The designer can make product artificially and analyze it and can document the design. All these factors help the designer in the improving the productivity of the product in terms of faster designs, lowering the cost and the time for the project completion.
Improve the quality of the design:
In the CAD software the designers can design any product with large number of tools provided in the software which helps in the finishing the required operations. With the help of tools the designer can check the faults in the design. The CAD software provides accurate structure of the product so that errors are reduced highly which leads to a better design, manufacturing of the product is also faster and this can reduces the wastage which occurs when the design is fault.
In the designing the product drawings are also the important part. For getting a standardized drawing easily the CAD software is used. In the CASD software the drawings can be read clearly and the documentation of the design will be better which again minimises the errors in the drawing.
Creating the documentation of the design and drawings:
CAD software not only helps in the designing it also useful for creating the documentations for which the design is done. The documentation includes geometries and dimensions of the design model and also includes assemblies and subassemblies of the component, the component material specifications.
Creating data base for Manufacturing:
The design documentation relating to the manufacturing data is created in the same way that is followed to create drawing for products and components, dimensions, material requirements for the component etc...
saving the design data and drawings
After the drawing all the data which is used can be saved, the saved data can be used for further references where in it helps the designer for not designing the sane component or raw the same design once again. And whenever required the design or the drawings which are saved can be taken in many number of copies. Some of the drawings can be standardized and those drawings can be used as references for any future drawings.
INDUSTRIAL CASE STUDY
BOEING COMMERCIAL AIRLINES COMPANY
"A typical aerospace industry application at Boeing Commercial Airplane Company is described in the following section adapted from BOEING UNVEILS NEW 757: ON TIME/ON SCHEDULE WITH CAD/CAM by K.C. CHARTRANAND, which appeared in Computer Graphics News, January/February 1982".
Boeing Company launched its air craft Boeing 757 to the public on January 13th 1982 for the first time at Renton Washington to facility. The Boeing 767 is called as the sister aircraft to 757, and the only difference to both the aircrafts was that 767 have wide body. 757 was the latest new generation commercial aircraft having all the latest Aviation Technology. Both the aircrafts Boeing 757 and 767 were manufacture with budget which was slightly under the estimated budget. This was done due to both aircrafts were designed and manufactured using COMPUTER DESIGN AND MANUFACTURING.
Most of the designing and production for 757 was done on CAD/CAM and is a great example of the extent of CAD/CAM capabilities in the commercial aircraft Industries till date. The new jets were benefited from the new innovation and technological improvements of the battery. First of all the aircraft was improved and designed in the field Aero Dynamically better power plant, the weight of the air craft was also reduced and most important improvement was the deck of the aircraft was redesigned. Without the help of CAD/CAM all these could not been possible to implement in the manufacturing of aircraft. Almost 45% of the work for manufacturing 757 aircraft was given to the contractors by Boeing Company. This was done to carry out the work with high productivity of CAD/CAM techniques. The Boeing Company started manufacturing the other aircrafts using computer to control the operations in the year 1958. But the both 757, 767 aircrafts were the first airlines to be manufactured using CAD and CAM. The main use of these technologies was they help the designer to correct the costly design errors and inconsistencies before actual manufacturing is started, thus resulting in the saving both money and time.
The CAD program at Boeing currently includes the application of three basic computerised elements.
- Lofting program use preliminary base line design.
- Automated program tools (APT) software language program.
- Interactive computers graphics are used to complete drawings.
These techniques were used by Boeing 757 designers to design and draw and data sets from which the air craft was build. The designers of 757 formed into a business company with legal status and took CAM to new level. Even with the use of computers the manufacturing was not as good as in engineering and manufacturing was low by 7% in tool design.
Sheet metal components like the Myriad Bracket, Gussets hangs were one of the best examples to show that the applications of CAD/CAM in Boeing manufacturing before the introduction of CAD/CAM .The components were made manually and then used to build templates individually and the average time of whole manufacturing time was about 2 to 3 weeks and this was before introduction of CAD/CAM.
So after the introduction of CAD/CAM the manufacturing of the same components and the terminals was simple and the whole process was brought down to 1 hour. The two numerically controlled routers are automatically generated by the systems. In the manufacturing of Boeing 757 dynamic aircraft CAD plays a duel role as it changed in the design work by replacing the traditional draft man table. The engine is the most important part in the aircraft as it comes in the fact of fuel efficiency. 757 have 2 types of engines one is the ROLLS-ROYCE RB 211-535C and the other engine is the PRAFT AND WHITNEY PW2037. For these two engines manufacturing the designers have used CAD/CAM. It also helped the designers to reduce the weight of the aircraft in 2 ways added precision in design and manufacturing and used light weight building materials. The Boeing 757 cockpit and also the instruments in the cockpit were designed and manufactured by using CAD/CAM. The cockpit was designed by the CAD system and manufacturing from the same data base. In the aircraft industry there are many benefits in manufacturing with CAD/CAM and it is gaining importance in the market of aircraft manufacturing.
All the operations like better management control, greater design freedom, shorter lead time, greater operating flexibility, reduced maintenance, reduction in the scrap production helped Boeing aircraft 757 to be a better aircraft.
The future of the CAD/CAM can be predicted by the past development of the software. Over the last few years there is a drastic advancement in the usage of CAD software in terms of using of software, Graphics, Intelligence and automation. Even the 3D modelling designs like mechanical design software need to improvements very highly. The Mechanical deign software needs to be still faster, easier to use and also it should be user friendly to the Non Engineers in the area of computing or using the software. Since last decade not only the design tool were improved but also the CAD software related to the market has improved a lot. CAD software includes with CAD tools which enables accurate sharing of data for manufacturing team. Throughout the development of CAD software the CAD tools were improved along with the development of the software and this will continue in the coming years as well. The 3D software is slowly increasing the design process speed and also suggestions while designing and identifying the problems while designing made CAD software much easier to use. This will help to gain knowledge in the concept of designing and construction planning.
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