Unit-II Basic Mechanical Engineering.pptx

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1. BASIC MECHANICAL ENGINEERING Dr. G.Praveen Kumar Assistant Professor Department of Mechanical Engineering Unit-II MANUFACTURING PROCESSES

2. Course Outcomes: CO1: Understand the different manufacturing processes. CO2: Explain the basics of thermal engineering and its applications. CO3: Describe the working of different mechanical power transmission systems and power plants. CO4: Describe the basics of robotics and its applications.

3. BASIC MECHANICAL ENGINEERING Unit-II Manufacturing Processes: Principles of Casting, Forming, joining processes, Machining, Introduction to CNC machines, 3D printing, and Smart manufacturing. T hermal Engineering – working principle of Boilers, Otto cycle, Diesel cycle, Refrigeration and air-conditioning cycles, IC engines, 2-Stroke and 4-Stroke engines, SI/CI Engines, Components of Electric and Hybrid Vehicles.

4. Manufacturing Manufacturing basically implies making of goods or articles and providing services to meet the needs of mankind. Manufacturing process Manufacturing is the process of turning raw materials or parts into finished goods through the use of tools, human labor, machinery, and chemical processing.

5. Classification of manufacturing processes

6. Principles of Casting The casting process is the manufacturing process in which molten material such as metal is poured into the casting cavity or mold of the desired shape and allowed to harden or solidify within the mold , after solidification the casting is taken out by ejecting or by breaking the mold.

7. Casting Terminology • Pattern : An approximate duplicate or true replica of required product of casting Flask/Box: The rigid metal or a wooden frame that holds the moulding material Cope: Top half of the moulding box Drag: Bottom half of the moulding box Core: As and shape that is inserted into a mould to produce internal features of a casting such as holes. Gating System: Channels used to deliver the molten metal to the mould cavity Sprue: The vertical passage in the gating system Runner: The horizontal channel of the gating system Gate: Channel which connects runner and mould Riser : A vertical opening in the mould Act as a vent for gases Helps to confirm that the mould is completely filled Act as a reservoir of molten metal to feed and compensate for shrinkage during solidification of a casting

8. Have you seen any similar process before? What do we control? Size & shape of cavity and mold Mixture composition Temperature Cooling time Carefully remove it

9. Basic steps in Casting Pattern making Mold making Melting of metal and pouring Cooling and solidification of metal Cleaning of casting and inspection

10. Basic Casting Process

11. Basic Casting Process

12. Advantages Product can be cast as one piece and hence the metal joining process is eliminated. Very heavy and bulky parts can be manufactured Metals difficult to be shaped by other manufacturing processes may be cast ( eg : Cast Iron) Casting can be employed for mass production as well as for batch production . Complex shapes can be manufactured

13. Disadvantages of Casting Casting process is a labour intensive process Not possible for high melting point metals Dimensional accuracy, surface finish and the amount of defects depends on the casting process Allowances required.

14. Applications Transportation vehicles(eg.:engines) Machine tool structures. Turbine vanes Mill housing Valves Sanitary fittings Agricultural parts Construction &atomic energy applications.

15. Types of the casting process: Shell Casting Investment Casting Full Molding CO2 Molding Sand Casting True Centrifugal Casting Gravity Die Casting Pressure Die Casting Hot Chamber Die Casting Cold Chamber Die Casting and Slush Casting

16. Forming Forming is a mechanical process used in manufacturing industries wherein materials (mostly metals) undergo plastic deformations and acquire required shapes and sizes by application of suitable stresses such as compression, shear and tension.

17. Types The type of Forming Operations is as follows Rolling Forging Extrusion Wire Drawing Roll forming Stamping

18. Rolling

19. Rolling Roll forming is a continuous process which converts sheet metal into an required shape using consecutive sets of mated rolls, each of which makes only incremental changes in the form . The sum of these small changes in form is a complex profile. The Forming Process.

20. Forging Forging is a manufacturing process involving the shaping of metal using localized compressive forces . The blows are delivered with a hammer or a die . Forging is often classified according to the temperature at which it is performed: cold forging, warm forging, or hot forging .

21. Extrusion Extrusion is a metal forming process in which metal or work piece is forced to flow through a die to reduce its cross section or convert it into desire shape . This process is extensively used in pipes and steel rods manufacturing. The force used to extrude the work piece is compressive in nature.

22. Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through a single, or series of, drawing die(s). Wire Drawing

23. Roll forming Roll forming is a continuous process which converts sheet metal into an engineered shape using consecutive sets of mated rolls, each of which makes only incremental changes in the form. The sum of these small changes in form is a complex profile. The Forming Process.

24. Stamping Stamping is the process of placing flat sheet metal in either blank or coil form into a stamping press where a tool and die surface forms the metal into a net shape.