CAD/CAMPrepared by:

Ahmed Hassan

Mahmoud Salah

Hussein Khaled

Computer Aided Design (CAD)

• Use of computer systems to assist in creation,

modification, analysis and optimization of a design.

• Computer assistance while a designer converts his

or her ideas and knowledge into a mathematical and

graphical model represented in a computer.

Definition of CAD depend on its constitute

Computer graphics

geometric modeling

Design tools

(analysis, codes, etc.)

Definition of CAD depend on implementation

Computer Aided Manufacturing

(CAM)Use of computers systems to plan, manage and

control the operations of a manufacturing plant

1. Computer monitoring and control

2. Manufacturing support applications

Definition of CAM depend on its constitute

Networking

CADManufacturing

tools

Definition of CAM depend on implementation

Difference Between CAD and CAM• CAD just turns out the designs of things.

• CAM is the actual machines which cut and bend

metal, shape plastics, spray paint, etch surfaces

etc.

Computer Integrated

Manufacturing (CIM)Computer Integrated Manufacturing (CIM) is

considered a natural evolution of the technology of

CAD/CAM which by itself evolved by the integration

of CAD and CAM.

CIM - A process of integration of CAD, CAM and

business aspects of a factory. It attempts complete

automation with all processes functioning under

computer control.

Objectives of CIM1. Production improvement

2. Cost reduction

3. Fulfillment of delivery dates

4. Quality improvement

Operating system• An Operating System is

basically a set of

programs that provide

control of the CPU

(Central Processor Unit)

and its resources.

Operating system• Important functions of an operating system:

a) Transferring data between computer and various

peripheral devices for input and output.

b) Managing computer files and programs through

processor management.

c) Loading computer programs into memory and

controlling program execution.

d) Security.

e) Human Interface.

Operating system• Three major types:

a) ROM monitor.

b) Operating environment.

Geometric modeling

Definition• Computer representation of the geometry of a

component using software is called a geometric

model.

• Geometric modeling is done in three principal ways.

They are:

i. Wire frame modeling.

ii. Surface modeling.

iii. Solid modeling.

Wire frame modeling

• In wire frame modeling the object is represented by

its edges.

Surface modeling

Surface modeling• Apart from standard surface types available for

surface modeling (box, pyramid, wedge, dome,

sphere, cone, torus, dish and mesh) techniques are

available for interactive modeling and editing of

curved surface geometry.

Solid modeling• The representation of solid models uses the

fundamental idea that a physical object divides the

3-D Euclidean space into two regions, one exterior

and one interior, separated by the boundary of the

solid.

• There are many common representations in solid

modeling.

Solid modeling• Spatial Enumeration:

• hical adaptation

Solid modeling• Boundary Representation:

Solid modeling• Constructive Solid Geometry (CSG):

Importance• Geometric modeling used for quick and reliable

design analysis.

• provide important data such as volume, mass, mass

properties and center of gravity.

• The designer can also export models created to

other applications for finite element analysis (FEA)

• rapid prototyping and other special engineering

applications.

Engineering analysis

Introduction

• For any engineering design, some type of analysis is

required. The analysis may involve stress- strain

calculations heat transfer calculations, the use of

differential equations to describe the dynamic

behavior of the system being designed. The

computer can be used to aid in this analysis work.

Limitations• Traditional approach to design analysis involves the

application of classical or analytical techniques. This

approach has the following limitations:

i. Stresses and strains are obtained only at macro

level.

ii. information will not be available on critically

stressed parts of the components.

iii. simplifications and assumptions to design

complex components and systems

iv. Manual design is time consuming and prone to

errors.

FEA

• FEA is a convenient tool to analyze simple as well as

complex structures.

Types of analysis• structural analysis (static and dynamic analysis).

• thermal analysis.

• fluid flow analysis.

• field analysis (electrical, magnetic, electromagnetic

and electrostatic).

• manufacturing simulation and optimization.

General steps• select the element type and discretize the

component

• derive the element stiffness matrix

• assemble global stiffness matrix

[F] = [k]{d}

• solve to obtain nodal displacements

• solve for element strains and stresses

Design Review and Evaluation

General steps(i) Dimensioning and tolerance routines

(ii) Interference checking..

(iii) Kinematics

Automated Drafting

Definition• Automated drafting capabilities in CAD systems

facilitate presentation, which is the final stage of the

design process. CAD data, stored in computer

memory, can be sent to a pen plotter or other hard-

copy device

Command, Menu And Icon Driven

Software

3D printing

3D printing• Is a process of making three dimensional solid

objects from a digital model. 3D printing is achieved

using additive processes, where an object is

created by laying down successive layers of

material.

• 3D printing is usually performed by a materials

printer using digital technology.

Principles3D Designs

• The use of additive manufacturing takes virtual designs from computer aided design (CAD) or animation modeling software, transforms them into thin, virtual, horizontal cross-sections and then creates successive layers until the model is complete. It is a WYSIWYG process where the virtual model and the physical model are almost identical.

• The standard data interface between CAD software and the machines is the STL file format. An STL file approximates the shape of a part or assembly using triangular facets. Smaller facets produce a higher quality surface. VRML (or WRL) files are often used as input for 3D printing technologies that are able to print in full color.

PrinciplesPrinting

• To perform a print the machine reads in the design

and lays down successive layers of liquid, powder,

or sheet material, and in this way builds up the

model from a series of cross sections. These layers,

which correspond to the virtual cross section from

the CAD model, are joined together or fused

automatically to create the final shape. The primary

advantage of additive fabrication is its ability to

create almost any shape or geometric feature.

• Typical layer thickness is around

100 micrometers (0.1 mm),

Applications• Rapid prototyping

• Rapid manufacturing

• hobbyist uses

Video 2 (Sensormate)

Database• In essence, the successful implementation of CIM

lies in the efficient way relevant data is shared

among the different segments of CIM.

• The information required for manufacturing is

complex covering a wide range of disciplines and

serving a multitude of inter-related yet vastly differing needs.

Database• The CIM database comprises basically four classes

of data:

a) Product Data.

b) Manufacturing Data.

c) Operational Data.

d) Resource Data.

Database

Database• Definition of database:

A collection of data in a single location designed to

be used by different programmers for a variety of

applications.

A collection of logically related data stored

together in a set of files intended to serve one or

more applications in an optimal fashion.

Database• Classifications of Data:

a) Physical Data.

b) Logical Data.

c) Data Independence.

Database• Objectives of database:

a) Reduce or eliminate redundant data.

b) Integrate existing data.

c) Provide security.

d) Share data among users.

e) Incorporate changes quickly and efficiently.

f) Exercise effective control over data.

g) Simplify the method of using data.

h) Reduce the cost of storage and retrieval of data.

i) Improve accuracy and integrity of data.

Database• Features of database management system:

a) Organize a database.

b) Add new data to the database.

c) Sort the data in some meaningful order.

d) Print the data into formatted reports.

e) Edit the data.

f) Delete the data.

Database• Database models:

a) Hierarchal database.

b) Network database.

c) Relational database management system.

Process planning• Process planning is concerned with determining the

sequence of individual manufacturing operations needed to produce a given part or product.

Process planning• The resulting operation sequence is documented

on a form typically referred to as operation sheet.

• The operation sheet is a listing of the production

operations and associated machine tools for a work part or assembly.

Process planning• The process planning activity can be divided into several

steps:

a) Selection of processes and tools.

b) Selection of machine tools/Manufacturing equipment.

c) Sequencing the operations.

d) Grouping of operations.

e) Selection of work piece holding devices and datum surfaces (set ups).

f) Selection of inspection instruments.

g) Determination of production tolerances.

h) Determination of the proper cutting conditions.

i) Determination of the cutting times and non-machining times (setting time, inspection time) for each operation.j) Editing the process sheets.

Process planning• Advantages of process planning software:

a) Reduces the skill required for a planner.

b) Reduces the process planning time.

c) Reduces the process planning and manufacturing

costs.

d) Creates more consistent plans.

e) Produces more accurate plans.

f) Increases productivity.

Process planning• Operations of a typical computer aided process

planning software:

a) Process planning.

b) Creating a new plan.

c) Retrieval of plan.

d) Summary information.

e) Report generation.

Process planning• Disadvantages of CAD based process planning:

a) The inability to represent special manufacturing

techniques like coatings and surface treatment.

b) Lack of data interchange between some drafting

representations.

c) In the case of precision components, the process

design can be extremely complex.

CNC System and Machines

CNC MachineThe Important Mechanical Parts of CNC Machine

• 1‐Machine structure

• 2‐Guide ways

• 3‐Linear motion transmission elements

• 4‐Torque transmission units

• 5‐Spindle and Spindle bearings

• 6‐Tool mechanisms

• 7‐Chip removal mechanisms

• 8‐Guards

1‐Machine structure

2‐Guide ways

3‐Linear motion transmission elements

4‐Torque transmission units

5‐Spindle and Spindle bearings

6‐Tool mechanisms

7‐Chip removal mechanisms

8‐Guards

CNC SystemAn operational numerical control system consists of the

following three basic components:

1. Program

2. Controller unit

3. Machine tool or other controlled process.

Controller unit

• It consists of the electronically elements which are

required to read and interpret the program of

instructions and converted it to the required

actions.

Controller unit• It included the following items:‐

1‐Tape reader

2‐Data buffer

3‐Signal output channels to the machine tool servomotors

and other machine controls come from controller unit.

4‐Feedback channels from the machine tool to the

controller to make certain that the instructions have been properly executed by the machine.

5‐The sequence controls to coordinate the overall

operation over all machine elements.

6‐The control panel by which the operator runs the NC

system. It also contain data displays

How Numerical Control Operates Machine Tools?The following steps summarize how NC works:

• Numerical data feed into the system by punched tape, floppy disk, magnetic tape, or directly from a computer

• A translating unit reads the data and changes it into an electrical form that the machine tool can understand

• A memory system stores the data until it is needed

• Servo units (transducers) on the machine tool convert the data into actual machine movements

• A gauging device measures the machine movements to determine if the servo units have driven the correct commands

• A feedback unit feeds information back from the gage device for comparison so that the machine moves to the correct location

PROGRAMMING FEATURES

Some standard programming features include:

• Absolute/Incremental programming

• Decimal point programming

• Diameter/Radius Programming

• Linear, circular and helical interpolation

• Multiple part program storage

• Sequence number search

• Feed/min or feed/rev Programming

• Dwell programming (In block containing dwell

code)

• Position preset.

CodesPreparatory codes and miscellaneous codes:A typical line of a CNC program (called block) is given below:

N 0040 G01 X100.05 Y180.95 F15 S450 M08 $

This type of formatting the program is referred to as word address format. Other commonly used word addresses are :• T for tool• V for cutting speed• A for angle, etc. G-codes or G functions are mainly NC functions. These are also called preparatory functions.Some of these have been assigned standard functions and others are left to be defined by the CNC system manufacturers.

Some Preparatory Codes(G codes)

Interpolation Function

• Positioning (Rapid

Movement) (G00)

• Linear interpolation

(G01)

• Circular interpolation

(G02, G03)

Inch-metric conversion

(G20, G21)

Canned cycles:

• Outer diameter cutting

cycle (G90)

• Thread cutting cycle (G92)

Feed functions:

• Feed per minute (G98)

• Feed per revolution (G99)

• Dwell (G04)

Miscellaneous Codes (M Codes)

• M02 End of program

• M03 Spindle CW

• M04 Spindle CCW

• M08 Coolant on

• M09 Coolant off

• M06 Tool change

• M30 End of program and rewind

Effect of CAD/CAM on CNC

• The integration of CAD and CAM has resulted in a

paradigm shift in the methodology of NC

programming. Today it is possible not only to

generate CNC program required to manufacture a

component directly from the CAD model but also

design and model the fixturing set up, design the

blank, process plan, select optimum process

parameters, and simulate the machining operations

on the CAD/CAM workstations to ensure that the

program is capable of producing acceptable

components.

CAD/CAM to CNC program

• The block diagram shown illustrates the steps

involved in creating a NC program using a CAM

software package. The starting point of CAM is the

CAD file.

Video 2 (Mazak)

Robots• Definition of a robot:

A device that performs functions ordinarily ascribed

to human beings, or operates with what appears to

be almost human intelligence.

Robots• Elements of a robot system:

a) Components of the robot manipulator.

b) Control system.

c) Computer system.

Robots• Objectives of using robots:

a) Capabilities superior to human beings.

b) Better to perform single and repetitive tasks.

c) Perform tasks that are difficult and hazardous.

d) No limitations and negative attributes as humans.

e) Lower costs through efficiency and consistency.

f) Flexible since they can be reconfigured and

reprogrammed.

Robots• Classification based on mechanical configuration:

a) Rectangular Co-ordinate Robots.

b) Cylindrical Co-ordinate Robots.

C) Spherical Co-ordinate Robots

d) Revolute Co-ordinate Robots.

Robots• Classification according to freedom of motion:

a) Roll.

b) Pitch.

c) Yaw.

Robots• Classification according to drive systems:

a) Pneumatic.

b) Hydraulic.

c) Electric.

Robots• Classification according to control systems:

a) Robot control through non servo operation.

b) Servo controlled robots.

Robots• Programming methods:

a) Guiding.

b) Teach pendant.

c) Off-line programming.

d) On-line programming.

Robots• Robot programming activities:

a) Modeling the workspace.

b) Path generation.

c) Sensing.

d) Programming support.

Robots• Robot modes of operation:

a) Pick and place.

b) Point to point.

c) Continuous path.

d) Controlled path.

Robots• Applications:

a) Material handling.

b) Machine tending.

c) Welding.

d) Surface coating.

e) Machining.

f) Assembly.

g) Inspection.

Robots

Shop floor data collection systems

• Monitoring the progress of the jobs is an integrated

part of CIM.

• Collection of machine data statistics, estimation of

the non-production times and machine utilization,

tracking of flow of materials, determination of job

completion times and realization of schedules, etc.

are necessary to evaluate the efficiency of the

functioning of the system.

• This requires automatic or direct data collection

from the shop floor.

• The techniques and technologies by which the

status of production is collected are called shop

floor data collection.

SHOP DATA REQUIREMENTS

• PEOPLE - AVAILABILITY

a: Workstations

b: Idle

c: Absent

• MACHINES - STATUS

a: Idle

b: Setup

c: Production

d: Delay

• PARTS/RAW MATERIALS

LOCATION

a: Raw Stores

b: Transit

c: On-machine

d: Waiting

e: Finished stores

f: Assembly

g: Missing

TYPES OF DATA COLLECTION SYSTEMS

• ON-LINE DATA COLLECTION SYSTEMS

• OFF-LINE DATA COLLECTION SYSTEMS

Manual Data Input Techniques

• CENTRALIZED TERMINAL

• SATELLITE TERMINALS

• WORK CENTRE TERMINALS

AUTOMATIC DATA COLLECTION SYSTEM

The advantages of the automatic data collection

methods are:

• The accuracy of data collected increases

• The time required by the workers to make the data

entry can be reduced.

Computer aided quality control

The quality control (QC) function has traditionally

been performed using manual inspection methods

and statistical sampling procedures.

A wide range of computer-based instrumentation is

being used for quality control. In particular the

increased sophistication of sensors and transducers is

making it easier to carry out pre-process, in-process,

and post-process inspection. Inspection and testing

are meant to reduce wastage and make maximum

use of resources.

At present, inspection with the use of computers has

acquired a status of its own known as COMPUTER

AIDED INSPECTION (CAI) and is an integral part of

Computer Integrated Manufacturing.

important benefits of CAQC.i. With Computer aided inspection and computer

aided testing inspection and testing will typically be

done on a 100% basis rather by the sampling

procedures normally used in traditional QC.

ii. Inspection is integrated into the manufacturing

process. This will help to reduce the lead-time to

complete the parts.

iii. The use of non-contact sensors

CIM hardware and CIM software

CIM Hardware comprises the

following:• CNC machines

• robotic work cells

• tool handling devices

• storage devices

• Sensors, controllers

• shop floor data collection devices

• inspection machines etc.

• Management Information System

• Sales

• Marketing

• Finance

• Modeling and Design

• Analysis

• Simulation

• Communications

• Production Control

• Inventory Control

• Materials Handling

• Process Planning

• Quality Management

CIM software comprises computer programs to carry out some functions

• Software packages used for conceptual design like

Alias and for geometric modeling like solid

modeling (Solid Works, CATIA, Pro/Engineer etc.).

• Application software which includes the programs

for design analysis, simulation, tool design, process

planning, CNC programming, computer inspection

etc.

NATURE AND ROLE OF THE

ELEMENTS OF CIM SYSTEM

CIM models• Manufacturing management today has to face

several challenges, in order to be competitive in the

world market:

a) Introduction to changes in specifications.

b) Capacity management.

c) Tracking.

d) Balance between make to order and make to stock.

CIM models• Siemens model:

CIM models• The manufacturing industries have to deal with a

number of challenging issues to day:

a) Raising customer expectations.

b) Globalization.

c) Developments in technology.

d) Access to information.

e) Environmental concerns.

f) Intense competition.

Product development through CIM

Product development through CIM

• CIM helps to reduce the product development cycle

time.

• Product Development have two approaches:

sequential and concurrent Engineering

approaches

Sequential Approach• It includes product design, development of

manufacturing process and supporting quality and

testing activities, all carried out one after another.

• This situation assumes that there is no interaction

among the major departments involved in product

manufacturing during the initial development

process.

• Often the need for engineering changes is

discovered during planning or manufacturing or

assembly.

Sequential Approach• This will lead to conflicts, each department sticking

to their own decisions and may often require

intervention of senior management to resolve

conflicts or differences in opinion.

• Design changes will involve both material and time

wastages.

Concurrent Engineering Approach

• Concurrent engineering is a methodology of restructuring the product development activity in a manufacturing organization using a cross functional team approach

• It is a technique adopted to improve the efficiency of product design and reduce the product development cycle time.

• Concurrent Engineering brings together a wide spectrum of people from several functional areas in the design and manufacture of a product. Representatives from R & D, engineering, manufacturing, materials management, quality assurance, marketing etc. to develop the product as a team.

Concurrent Engineering Approach

• The teamwork also brings additional advantages ;

the co-operation between various specialists

ensures quick optimization of design and early

detection of possible faults in product and

production planning.

• This additionally leads to reduction in lead time

which reduces cost of production and guarantees

better quality

Comparison between both approaches

REDUCTION IN THE NUMBER OF

DESIGN CHANGES

CE

Sequential

COST OF CHANGES IN DESIGN

HOLISTIC APPROACH TO

PRODUCT DEVELOPMENTConcurrent engineering approach introduces a new

philosophy in product development:

• No longer is product development considered the

exclusive activity of the design department.

• Participation of planning, manufacturing,… etc.

personnel in the development process enables the

cross functional team to view the development as a

total responsibility and this results in better

communication among the various departments.

ROBUST PRODUCTS• Concurrent approach to product design results in

products with fewer errors and therefore avoids the

loss of goodwill of the customers due to poorly

engineered products.

• The entire product development team looks at

each and every aspect of products for example:

cost, specifications, aesthetics, ergonomics,

performance and maintainability.

• The resulting product will naturally satisfy the

customer.

REDUCTION IN LEAD TIME FOR

PRODUCT DEVELOPMENT• Time compression in product development is an

important issue today.

• Concurrent engineering reduces the product

development time significantly as the preparatory

work in all functions can take place concurrently

with design.

• Elimination of the errors in design appreciably

reduces the possibility of time overrun, enabling the

development schedule to be maintained.

Simulation• Simulation in manufacturing refers to a broad

collection of computer based applications to

imitate the behavior of manufacturing systems.

• A system is a facility or a process either

• actual or planned such as factory with workers,

machine tools, materials handling devices, storage devices etc.

Simulation• Factory simulation involves creating a virtual

factory.

• Instead of simulating a process or a work center the

entire factory is simulated to have a clear

understanding of the working of the plant as a whole.

Simulation• In addition to usual applications like system design

and performance estimation, simulation can also

be used for scheduling.

• The simulation software in this case gathers the

required data from manufacturing execution

system and generates multiple schedules from which optimum could be selected.

Simulation• Classified into three types:

a) Static or dynamic simulation.

b) Continuous or discrete.

c) Deterministic or stochastic.

Simulation• Techniques of simulation:

a) Simulation using general purpose languages.

b) Simulation using simulation languages.

c) High level simulators.

Simulation• Simulation process for manufacturing system

analysis:

a) Model design.

b) Model development.

c) Model deployment.

Simulation• Simulation software packages:

a) Analytica.

b) Crystal ball.

c) Extended OR.

d) GPSS.

e) Pro model.

f) SIGMA.

CAD/CAM• CAD/CAM - Key to improve manufacturing productivity

and the best approach for meeting the critical design requirements.

• CAD/CAM software provides engineers with the tools needed to perform their technical jobs efficiently and free them from the tedious and time-consuming tasks that require little or no technical expertise.

• CAD/CAM software speeds the design process, therefore increasing productivity, innovation and creativity of designers.

• CAD/CAM is the only mean to meet the new technological design and production requirements of increased accuracy and uniformity

Advantages • Software Flexibility

• Design Flexibility

• Automatic Specification Checking

• Design Time

• Design Variations

• Precision and Repeatability

• Marketing and Sales

Disadvantage• Processing Power Limitations and Cost

• Software Complexity

• It is easy to lose data if files are not regularly

‘backed up’. Disadvantages of Using CAD/CAM

• There is a lack of opportunity to experiment with

real materials and 3D forms.

Aerospace & DefenseAerospace and defense components demand quality

of the very highest standard, and are frequently

made from a solid block of a tough material such as

titanium.

Because long and complex operations are common,

the added value within the components can be

considerable, making errors in machining very costly

indeed.

For aerospace components these factors are

particularly important, as tool failure can seriously

damage the part, while excessive machining forces

can be deleterious to the material structure, which

may affect the performance of the finished part.

Safety is a key issue in the aerospace and defense

industries, so traceability of batches and material is

very important, as is a record of quality assurance

activities such as calibration, inspection and design

change.

Medical & DentalCAD/CAM Dentistry (Computer-Aided Design and

Computer-Aided Manufacturing in Dentistry) is an

advanced area of dentistry that uses computer

technology to help design and manufacture different

types of dental restorations.