Mechanical Design

Mechanical Design Basics

• Involves creating and improving designs for machines, equipment, or processes.

Difference Between Drawing, Drafting, and Design

• Drawing: A rough sketch to convey ideas.
• Drafting: Precise, scaled engineering drawing using standards.
• Design: A complete plan or prototype, including analysis.

CAD, CAM, CAE

• CAD: Computer-aided design (2D/3D models and drawings).
• CAM: Computer-aided manufacturing (machine control, NC programming).
• CAE: Computer-aided engineering (simulation).

Types of Projections

• Orthographic: Parallel lines.
• Oblique: Drawn at 45° angle.
• Perspective: Realistic 3D look.

Orthographic Projections

• 1st Angle and 3rd Angle projections are used.
• 2nd and 4th Angle are not used due to overlapping views.

1. Introduction to Engineering Drawing

Isometric and Orthographic Projections

2D Drawings in CAD

• Objective: To generate 2D Drawings
• Platform: Fusion 360

2D Drafting

Objective: To draw Level 2 Sierpenski Triangle and generate a drawing sheet with dimensions neatly labelled.

3D Drafting

Task 1

• Objective: To draw an Allen key and generate a labelled drawing sheet for the same. Along with a 3d model for the same in Fusion 360.
• Parameters: Length - 55mm Width - 20mm Size - 3mm
• Platform: Fusion 360

2. 3D Modelling

Solid Modelling

Objective:

• To design a simple airfoil for an HTOL aircraft using Fusion360. Make use of Plug-Ins and add ons to generate a NACA airfoil.
• Understand the nomenclature of NACA profile and understand the meaning of those terms.
• Understand the basic aspects of a wing design like leading, trailing edge and camber line.

What is an Airfoil?

The cross-sectional shape of an aircraft's wing is called as an airfoil. It is responsible for generation of lift of aircraft.

Generation of Lift:

• Lift is created because of the pressure difference in the upper and lower surface of the airfoil.
• The flow of air is faster in the upper surface then the lower surface ( velocity is inversely proportional to pressure).
• So the air pressure is lesser in the upper surface and higher in the lower surface.
• The lift depends on Shape, Velocity, Density, Surface area, Angle of attack of the airfoil.
• Angle of attack is the angle between the wind and the chord line. As angle of attack increases, the lift increases.
• As the angle of attack increases after a threshold angle, lift decreases and drag increases. This is called as Stall. Angle at which Stall occurs is called Stall angle.

Some Basic Terms of an Airfoil:

Design of an Airfoil using Fusion