1. 1 Teaching Innovation - Entrepreneurial - Global The Centre for Technology enabled Teaching & Learning, N Y S S, India DTEL DTEL (Department for Technology Enhanced Learning)

2. DEPARTMENT OF MECHANICAL ENGINEERING IV-SEMESTER MACHINING PROCESSES 2 CHAPTER NO.1 Introduction to Machining Parameters

3. CHAPTER 1:- SYLLABUSDTEL. Introduction to machining 1 Tool materials, nomenclature and tool geometry of single point cutting tool, tool materials properties 2 classification, HSS, carbide Tool, coated tools, diamond coated too l, 3 Theory of Metal Cutting Introduction. Orthogonal and Oblique cutting. Mechanics of Metal Cutting, shear plane, 4 3 Stress, Strain and cutting forces. Merchant’s circle 5 Chip formation, cutting force calculations, Determination of Torque and power required for turning Drilling and Milling 6

4. CHAPTER-1 SPECIFIC OBJECTIVE / COURSE OUTCOMEDTEL Understand tool significance. 1 Chip mechanisms.. 2 4 The student will be able to:

5. LECTURE 1:DTEL 5 5 Introduction Cutting tool geometry 7 elements of a single point tool geometry

6. LECTURE 1:DTEL 6 6 Introduction to Machining Parameters Toolmaterials,nomenclature * The lathe is one of the older machine tool and came in existent from the early tree lathe which was then a novel device for rotating and machining a work held between two adjacent trees. A rope wound round the work with its one end attached to a flexible branch of a tree and a another end being pulled by a man causes the job to move intermittently. Lathe machine is said to be Father of machine The lathe were developed by Henry Maud slay in 1797, an Englishman. The main function of the lathe is to remove the metal from the work to give it a required shape and size. History:-

7. DTEL Cutting tool 7 LECTURE 2 CUTTING TOOL RELATED TERMS Single point versus multiple point Cratering –wear that forms a concave region on the tool Tool life – length of cutting time that a tool can be used Toughness – capacity to absorb energy without failing Hot hardness –capacity to retain hardness at high temperatures Cermets – combination of TiC, TiN, TiCN (CN = carbonitride), with nickel and/or molybdenum as binders Chip breaker – geometry designed into tool to break stringy chips Cutting fluid – Any liquid/gas applied to improve cutting performance CUTTING TOOL RELATED TERMS Single point versus multiple point Cratering –wear that forms a concave region on the tool Tool life – length of cutting time that a tool can be used Toughness – capacity to absorb energy without failing Hot hardness –capacity to retain hardness at high temperatures Cermets – combination of TiC, TiN, TiCN (CN = carbonitride), with nickel and/or molybdenum as binders Chip breaker – geometry designed into tool to break stringy chips Cutting fluid – Any liquid/gas applied to improve cutting performance

8. DTEL 8 LECTURE 2 Cutting tool materials Synthetic polycrystalline diamond (SPD) and cubic boron nitride (CBN) – typically used as coating on base tool material such as WC-Co…there is an affinity of SPD with iron and nickel; CBN does not have this affinity… expensive. Cutting tool materials Synthetic polycrystalline diamond (SPD) and cubic boron nitride (CBN) – typically used as coating on base tool material such as WC-Co…there is an affinity of SPD with iron and nickel; CBN does not have this affinity… expensive. tool materials properties

9. DTEL 9 LECTURE 3: Cutting tool materials – HSS alloying ElementProperties TungstenIncreases hot hardness Hard carbides formed, improving abrasion resistance MolybdenumIncreases hot hardness Hard carbides formed, improving abrasion resistance ChromiumDepth harden ability during heat treat Hard carbides formed, improving abrasion resistance Some corrosion resistance VanadiumCombines with carbon for wear resistance Retards grain growth for better toughness CobaltIncreases hot hardness, toughness CarbonHardening element Forms carbides Cutting tool materials – HSS alloying ElementProperties TungstenIncreases hot hardness Hard carbides formed, improving abrasion resistance MolybdenumIncreases hot hardness Hard carbides formed, improving abrasion resistance ChromiumDepth harden ability during heat treat Hard carbides formed, improving abrasion resistance Some corrosion resistance VanadiumCombines with carbon for wear resistance Retards grain growth for better toughness CobaltIncreases hot hardness, toughness CarbonHardening element Forms carbides classification,

10. DTEL 10 LECTURE 4: High-speed Steels High-speed Steel (HSS) Tools Were Developed To Machine At Higher Speeds Than Was Previously Possible They Can Be Hardened To Various Depths, Have Good Wear Resistance And Are Inexpensive There Are Two Basic Types Of High-speed Steels: Molybdenum (M-series) And Tungsten (T-series) High-speed Steel Tools Are Available In Wrought, Cast And Powder-metallurgy (Sintered) Forms They Can Be Coated For Improved Performance classification

11. DTEL 11 LECTURE 4: Cast-cobalt Alloys Cast-cobalt alloys have high hardness, good wear resistance and can maintain their hardness at elevated temperatures They are not as tough as high-speed steels and are sensitive to impact forces Less suitable than high-speed steels for interrupted cutting operations

12. DTEL 12 LECTURE 4: Cast-cobalt Alloys Cast-cobalt alloys have high hardness, good wear resistance and can maintain their hardness at elevated temperatures They are not as tough as high-speed steels and are sensitive to impact forces Less suitable than high-speed steels for interrupted cutting operations

13. DTEL 13 LECTURE 4: Carbides Also known as cemented or sintered carbides They have the following characteristics: 1.High hardness over a wide range of temperatures 2.High elastic modulus 3.High thermal conductivity 4.Thermal expansion 5.Versatile 6.Cost-effective tool and die materials for a wide range of applications