03 MEMB113 ENGINEERING GRAPHICS & CAE ENGINEERING DESIGN ENGINEERING GEOMETRY

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Contents Engineering design Engineering geometry How to draw? –Examples of previous exercises

Engineering Design

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

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Category of design DESIGN Product/Process Development (Technical) Product/Process Development (Technical) Personal Expression (Artistic) Personal Expression (Artistic) Aesthetic (Industrial design) Aesthetic (Industrial design) Functional (Engineering Design) Functional (Engineering Design) Engineering Design Cycle Engineering Design Cycle Product Process

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Engineering design Traditional engineering design sequence Concurrent design process

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY 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 sketches used for analysis to record the precise data for 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

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | 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 systemPolar coordinate system MEMB113 | MANUAL DRAWING | CHAPTER 3

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Overview Absolute coordinate & Relative coordinate Right hand rule –to determine positive direction of axis Absolute Relative Right hand rule

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Geometric elements Can be categorised as points, lines, surfaces, solids. Points, lines, circles and arcs are basic 2D geometric primitives. MEMB113 | MANUAL DRAWING | CHAPTER 3

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY 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. MEMB113 | MANUAL DRAWING | CHAPTER 3

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Geometric elements –Circle - is a single-curved-surface, all points of which are equidistant from one point, the center MEMB113 | MANUAL DRAWING | CHAPTER 3

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Geometric elements Major components of a circle MEMB113 | MANUAL DRAWING | CHAPTER 3

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

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY How to draw? All drawing consist of the combination of basic geometric elements. Some of the common elements: –Straight lines –Circles –Arcs –Freeform curves

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

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

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

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Line thickness not consistent Poor blending construction lines – too thick, need to erase circle construction – poor dimensioning – poor scale not written Drawing examples

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY Object lines – too thin Object lines & centre lines – same thickness Dimensioning – not follow standard Drawing examples

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

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

MEMB113 | Dept. of Mechanical Engineering | UNITEN | ENGINEERING DESIGN | ENGINEERING GEOMETRY 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: - Engineering Drawing, A.W. Boundy, McGraw-Hill, Fundamentals of Graphics Communication 3rd Edition, Gary Bertoline & Eric Weibe, McGraw-Hill