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Introduction to CAD/CAM- Short notes series for Mechanical Engineers

In this article on Short Notes series of CAD/CAM for GATE and other competetive exams for Mechanical Engineers we will introduce the concept of CAD/CAM and some important terms along with the introduction.

What is CAD/CAM?

CAD/CAM means computer aided design, and computer aided manufacturing. This technology makes use of the computers to perform and/or maintain certain functions in the industries for design and manufacturing. The utilisation of CAD/CAM can be divided into 4 groups:

  1. Group 1: It can be used to produce drawings and document drawings.
  2. Group 2: It can be employed as a visual tool by generating shaded images and animated displays.
  3. Group 3: It can be used to perform engineering analysis on geometric models like FEA.
  4. Group 4: It can be used to perform process planning and generate NC part programmes.

What is the role of computers in Industrial production and manufacturing?

With an every increasing focus to maintain high quality due to customer demand of competetion among businesses, manufacturing of high quality products has become imperative for every manufacturer. Computers have come in, with powerful multifunctional capabilities to help manufacturers deliver high quality and reliability in their products. 

The role of computers in industrial manufacturing can be broadly classified into three groups:

  1. Pre-processing support applications of the manufacturing system which involves processes like, computer aided design and drafting, FEA, computer aided programming, computer aided process planning and scheduling etc.
  2. Monitoring and control of the manufacturing process wherein the computers are directly interfaced with maufacturing. Monitoring means that there is a direct interface of the computer with the manufacturing process for the purpose of observing the process and collecting data from the process. 
  3. Post-processing support applications of the manufacturig system which consists of all support functions that help the computers to deliver high quality products, like computer aided assembly, computer aided inspection and quality control.

What is CAD?

CAD is defined as a design process using sophisticated computer graphics techniques, backed by computer software packages, to help in the analytical, development, costing and erogonomic problems associated with the design process. The implementation of the CAD process on a CAD/CAM system is described in the figure below. 

What is CAM?

CAM is defined as the use of computer systems to plan, manage and control the operations of a manufacturing setup through a computer interface, which may be direct or indirect in its application. The implementation of the CAM process on the CAD/CAM system is shown in the figure below. 

The geometric model is created during the CAD process and it forms the basis of the CAM process. Different activities in the CAM process require different types of information of the CAD process so we make use of interface algorithms, which extract such information from the CAD database. 

What is the meaning of Product Lifecycle?

Every manufactured product has a life and the demand for a product also doesn't last long. This means that every product will have its lifecycle which is driven by customers and markets, which demand the product. For every product, its product lifecycle begins with an idea or a concept. And as this concept goes through various phases, it is cultivated, refined, analysed, improved upon and translated into a plan with the help of a design engineering process. The figure below shows a conventional product lifecycle.

The above figure shows the product lifecycle for a traditional manufacturing environment, so once the design of the product is ready, the part prints are released for production. Before the part actually goes into production, the production engineering section would first consider the feasibility of production of that patricular product. After ascertaining the feasibility of the product, process planning is carried so that the product can be manufactured at the least possible cost. After the planning for the manufacturing is complete, the implementation is carried which include:

  • Making of the requisite tools
  • Purchasing new tools if needed
  • Raw material procurement
  • Releasing of detailed operational instructions on the shop floor. 

The product lifecycle of a computer-aided manufacturing environment is shown in the figure below.

Types of production.

All production activities can be classified according to the quantity of the product made. There are four types of production, job shop productionbatch production, mass production of discrete products and continuous flow process.

 

  1. Job shop production: This category is for a low volume of production. The lot sizes in this kind of manufacturing is very small. The type of work has huge variety, with flexible and general purpose manufacturing equipment. Some examples of products manufactured in a job shop are machine tools, space vehicles, aircrafts and prototypes of future products.
  2. Batch production: This type of production refers to the manufacturing of products in medium lots. The lots may be produced only once and may be manufactured at regular intervals. The main purpose of batch production is to take care of the continuous customer demand for an item. The equipment for production should be general purpose to accomodate for higher production rates. Batch production is used in industries like machine shops, casting foundries, press working shops and plastic moulding factories.
  3. Mass poduction: This kind of production involves very high volume of production, with equipment designed to cater to just aa particular type of product which has a very high demand rate. Example of industries using this type of production is automobile industry.
  4. Continuous flow production: In this type of production, continuous dedicated buk manufacturing of large amounts of a product is involved, e.g. chemical plants and oil refineries. 

We hope that you would have, after going through these short notes, have got an idea about what is CAD/CAM and how it benefits the industrial manufacturing. In the next article, we will study about the plany layout and different types of automation involved in production systems.

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