JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Pre- requisites

Engineering graphics, Mechanics of solids, Heat Transfer, Machine Tools, Strength

of Materials, Material Science and Metallurgy.

Course Objectives:

• To impart the knowledge of basic methodology of metal cutting.
• To educate the student about the structure, working, forces involved in single point and multipoint cutting tools.
• To understand the concepts of tool life, machinability, wear, influence of heat.
• To design the jigs and fixtures required for machine tools.

Course Outcomes

At the end of this course Students can

• Describe the metal cutting processes
• Explain the types of cutting tools
• Estimate the Speed, feed, depth of cut and their influence on surface roughness
• Estimate the tool life and tool wear
• Choose the cutting fluids, cutting tool materials for a specific application

UNIT - I

Mechanics of Metal Cutting: Geometry of Metal Cutting Process, Chip formation, Chip thickness ratio, radius of chip curvature, cutting speed, feed and depth of cut – Types of chips chip breakers. Orthogonal and Oblique cutting processes – definition, Forces and energy calculations (Merchant’s Analysis) – Power consumed – MRR- Effect of Cutting variables on Forces, Force measurement using Dynamometers.

UNIT - II

Single Point Cutting Tool: Various systems of specifications, single point cutting tool geometry and their inter-relation. Theories of formation of built-up edge and their effect, design of single point contact tools throwaway inserts.

UNIT - III

Multipoint Cutting Tool: Drill geometry, design of drills, Rake & Relief angles of twist drill, speed, feed and depth of cut, machining time, forces, milling cutters, cutting speed &feed machining time- design – from cutters. Grinding: Specifications of grinding of grinding wheel, mechanics of grinding, Effect of Grinding conditions on wheel wear and grinding ratio. Depth of cut, speed, machining time, temperature power.

UNIT - IV

Tool Life and Tool Wear: Theories of tool wear – adhesion, abrasive and diffusion wear mechanisms, forms of wear, Tool life criteria and machinability index. Types of sliding contact, real area of contact, laws of friction and nature of frictional force in metal cutting. Effect Tool angle, Economics, cost analysis, mean co-effect of friction.

UNIT - V

Cutting Temperature: Sources of heat in metal cutting, influence of metal conditions, Temperature distribution, zones, experimental techniques, analytical approach. Use of tool- work thermocouple for determination of temperature. Temperature distribution in Metal Cutting. Cutting fluids: Functions of cutting fluids, types of cutting fluids, properties, selection of cutting fluids.

Cutting tool materials: Historical developments, essential properties of cutting tool materials, types, composition and application of various cutting tool materials, selection of cutting tool materials.

TEXT BOOKS:

• 1. Metal Cutting Principles/ MC Shaw / Oxford and IBH Publications, New Delhi, 1969
• 2. Fundamentals of Machining /Boothryd/ Edward Amold publishers Ltd 1975.

REFERENCES:

• 1. ‘Tool Design’ by David Son / Lacain/ Goud, Tata Me Graw Hill.
• 2. Fundamentals of Tool Design by Wilson fw, ASTME PHI 2010.
• 3. Technology of machine tools, Steve F. Krar, Arthur R. Gill and Peter Smid, McGraw Hill Education (India) Pt. Ltd., 2013. M. TECH. I Year I Sem. (AMS)