03 MEMB113 ENGINEERING GRAPHICS & CAE ENGINEERING DESIGN ENGINEERING GEOMETRY.

03

MEMB113 ENGINEERING MEMB113 ENGINEERING GRAPHICS & CAEGRAPHICS & CAE

ENGINEERING DESIGN

ENGINEERING GEOMETRY

MEMB113 | Dept. of Mechanical Engineering | UNITEN | 200503 ENGINEERING DESIGN | ENGINEERING GEOMETRY

Contents

• Engineering design

• Engineering geometry

• How to draw?– Examples of previous exercises

Engineering Design


Design

• Design is the process of conceiving or inventing ideas mentally and communicating those ideas to others in a form that is easily understood.

• Normally using graphical way.• Generally, design is used for two primary

purposes:– Personal expression (usually art)– Product/process development


Category of design

DESIGNDESIGN

Product/ProcessDevelopment(Technical)

Product/ProcessDevelopment(Technical)

Personal Expression(Artistic)

Personal Expression(Artistic)

Aesthetic(Industrial design)

Aesthetic(Industrial design)

Functional(Engineering Design)

Functional(Engineering Design)

EngineeringDesign CycleEngineering

Design Cycle

ProductProduct ProcessProcess


Engineering design

• Engineering drawing in design process

to see the problem& possible solutions

Visualise

Sketches

Geometric model

Detail drawings

3D model

to record initial ideas

created from sketchesused for analysis

to record the precise datafor production process

Visualisation is the ability to mentally picture things that do not exist

Communication - the design solution should be communicated to others without ambiguity

Documentation - permanent record of the solution

Engineering Geometry


Overview

• Geometry provides the building blocks for the engineering design process.

• Engineering geometry is the basic geometric elements and forms used in engineering design.

• Coordinate system– cartesian coordinate system– polar coordinate system

Cartesian coordinate system Polar coordinate system

MEMB113 | MANUAL DRAWING | CHAPTER 3


Overview

• Absolute coordinate & Relative coordinate

• Right hand rule– to determine positive direction of axis

Absolute Relative

Right hand rule


Geometric elements

• Can be categorised as points, lines, surfaces, solids.

• Points, lines, circles and arcs are basic 2D geometric primitives.



Geometric elements

– Point - theoretical location that has neither width, height, nor depth. It describe an exact location in space. Represented as a small cross.

– Line - has length and direction, but not thickness. May be straight or curve or both.



Geometric elements

– Circle - is a single-curved-surface, all points of which are equidistant from one point, the center



Geometric elements

Major components of a circle



Tangent

• A line is tangent to a circle if it touches the circle at one and only one point.

• At exact point of tangency, a radius makes a right angle to the tangent line.

• Two curves are tangent to each other if they touch in one and only place.

Tangent point between a straight line & a circle

Tangent point between two circles (curves)

How to draw?


How to draw?

• All drawing consist of the combination of basic geometric elements.

• Some of the common elements:– Straight lines– Circles– Arcs– Freeform curves


How to draw?

• E.g. simple object as shown• Inspect the overall size of the

object – compare to the available drawing space to decide on the suitable scale

• Observe the feature• Start drawing

– Draw circle & arc first (if any)– Draw centre lines before that– Make sure of using correct pencil

or line thickness– Draw straight lines– Add in other things e.g.

dimensions, etc.• Be careful of ‘blending’ and

cleanliness of the drawing• Make your drawing sharp and

solid


Points to remember

• Overall shape & feature• Line quality (thickness,

consistency, etc.)• Size & scale• Dimension (if available)• Drawing quality

(cleanliness, etc.)• Projection (if any)• Other info


• Line quality – good• Good solid object line• line thickness – good use of thick & thin• construction of arc need to be improved• blending can be further improved

Drawing examples


• Line thickness not consistent• Poor blending• construction lines – too thick, need to erase• circle construction – poor• dimensioning – poor• scale not written

Drawing examples


• Object lines – too thin• Object lines & centre lines – same thickness• Dimensioning – not follow standard

Drawing examples


• Line quality – good• Good solid object line• line thickness – good use of thick & thin• construction of arc need to be improved• blending can be further improved

Drawing examples


• Object shape is wrong! •Line thickness not consistent• Poor blending• construction lines – too thick, need to erase• circle construction – poor• dimensioning – poor• scale not written

Drawing examples


• Line quality – acceptable but should be darker• blending between straight line & arc need improvement• good lettering• missing scale

Drawing examples

End of chapter [03]

References:References:- Engineering Drawing, A.W. Boundy, McGraw-Hill, Engineering Drawing, A.W. Boundy, McGraw-Hill, 20002000- Fundamentals of Graphics Communication 3rd Fundamentals of Graphics Communication 3rd Edition, Gary Bertoline & Eric Weibe, McGraw-Hill Edition, Gary Bertoline & Eric Weibe, McGraw-Hill

03 MEMB113 ENGINEERING GRAPHICS & CAE ENGINEERING DESIGN ENGINEERING GEOMETRY.

Documents

Transcript of 03 MEMB113 ENGINEERING GRAPHICS & CAE ENGINEERING DESIGN ENGINEERING GEOMETRY.