Sequential engineering involves completing each stage of product development sequentially before starting the next stage. This process is orderly but slow. Simultaneous engineering carries out design and manufacturing activities concurrently to reduce time to market. Computer aided design (CAD) utilizes computers to model products, enabling faster, more accurate design with ability to easily modify and reuse designs. It provides benefits throughout the manufacturing process.

1. Serial (or) Sequential Engineering
• Sequential engineering is the process of marketing, engineering design,
planning, manufacturing, quality, sales and service where each stage of
the development process is carried out separately, and the next stage
cannot start until the previous stage is finished.
• This orderly step by step process will control to complex projects but is
very slow.
• Flow is only in one direction.
• Time consumption is more.

2. Serial or Sequential Engineering

3. Simultaneous (or) Concurrent Engineering
• It deals with carrying out the design and manufacturing activities at
the same time (performing tasks concurrently) while designing the
product.

4. Inspection
Marketing
sales
packaging
Function
Assembly
Serviceability
Manufacturing
Design
coordinator
Concept of Simultaneous Engineering

5. Why Concurrent Engineering?
• Increasing product variety and technical complexity.
• Increasing global competitive pressure.
• The need for rapid response to fast-changing consumer
demand.
• The need for shorter product life cycle.
• Lower manufacturing and production cost.
• Reduced defect rate and ultimately a faster time to market.

6. COMPUTER AIDED DESIGN
• CAD utilizes the computer as a tool for all functions that are involved
in the design process.
• The main functions that would utilize the computer are
• Layout design for the overall assembly
• Individual component modelling
• Assembly modelling
• Interference and tolerance stack checking
• Engineering drawing

7. Uses of CAD
• To create conceptual product model.
• Display the product in several colors to select color combinations most
appealing to customers.
• Rotate and view the object from various sides and directions.
• Create and display all inner details of assembly.
• Check the interference or clearance between mating parts in static or
dynamic situations.

8. CAD technology provides the engineer/designer
the necessary help in the following ways:
• CAD is a faster and more accurate than conventional methods.
• It is useful of design work.
• You will never have to repeat the design or drawing of any component.
• You can accurately calculate the various geometric properties including
dimensions of various component.
• Modification of a model is very easy.
• Use of standard components makes for a very fast model development
work.

9. The benefits of CAD in manufacturing are
• Tool and fixture design
• Computer aided process planning
• Preparation of assembly lists and bill of materials
• Computer aided inspection
• Coding and classification of components

10. Application of CAD
• Printed circuit board
• Computer aided process planning
• Piping systems for process industries
• Finite element analysis
• Architecture – building design

11. CO ORDINATE SYSTEMS
• The right handed Cartesian coordinate system is used for defining the
geometry of the parts. In order to specify the geometry of a given solid,
it is necessary to use a variety of coordinate systems.
• They are the following
• World Coordinate Systems
• User Coordinate systems
• Display Coordinates
• View Generation

12. World Coordinate Systems
• This refers to the actual coordinate system used as a master for the
component. Sometimes, it may also be called the model coordinate
system.
• In this chapter, we will call it the world coordinate system (WCS).
Figure shows a typical component, which needs to be modelled.
• Another figure shows the component with its associated world
coordinate system, X,Y and Z.

14. User Coordinate Systems
• The default coordinate system when the user starts the modelling is the
WCS. However, sometimes it becomes difficult to define certain
geometries if they are to be defined from the WCS.
• In such cases, alternate coordinate systems can be defined relative to
the WCS. These coordinate systems are termed user coordinate systems
(UCS) or Working Coordinate systems.
• UCS reduces the modelling complexity.

16. DISPLAY COORDINATES
• This refers to the actual coordinates to be used for displaying the
image on the screen. It may also be termed the screen coordinate
system.
• The actual screen coordinates related to the pixels to determine
whether the actual values of the screen or the virtual image that can be
displayed are needed to help in the image display.

17. VIEW GENERATION
• The display screen is two dimensional. Sometimes. It is necessary to
organize the information when presented on the screen in two
dimensions using the orthogonal projection.
• The screen is therefore divided into a number of view ports where in
the various views are presented.

19. CAD SYSTEM ARCHITECTURE
• The CAD system comprise of the following
• Hardware
• Software
• Data
• Human knowledge and activities

20. The CAD elements are
• Model definition
• Model manipulation
• Picture generation
• User interaction
• Database management
• Utilities

21. Database
Component model
Library data
Standards
Drawing
Working data
Geometry
Associated data
Manufacturing
Applications
Database
management
Utilities
Picture generation
Manipulator
Model definition
Input /
Output
users
DATA FUNCTIONS

22. COMPUTER GRAPHICS
• Computer graphics is defined as creation, storage and manipulation of
picture and drawing by means of a digital computer.
• The user communicates data and commands to the computer through a
keyboard terminal and the computer communicates with the user via a
Cathode Ray Tube (CRT)

23. A typical hardware setup of a graphic system
keyboard
Floppy disk drive
(or) CD
I/O
(Interference/Mass
storage)
Microprocessor Video I/O TV Screen
System
RAM
Memory
Data Bus
Address Bus

24. List of parameter for CRT & flat panel displays are
• Screen size
• Resolution
• Dpi
• Screen type
• Brightness & contrast
• Viewing angle
• Video interface
• VGA controller
• Bit map (frame buffer)
• Display batch
• Lookup table
• Color palette
• Refresh rate
• Antialiasing

25. Computer graphics helps the designer
• The object is represented by its geometric model in three dimension.
• Drawing can be made very accurate.
• The geometric model can be represented in color and can be viewed
from any angle.
• Drawing can be modified easily.
• Storage and retrieval of drawings are easily.