ME661: Machining Science – I (3L-0T-0P-1D; Weightage 04)
No. of Lectures
1. Introduction : [2 Lectures]
Machining; Plastic Deformation, Tensile Test, Stress and Strain; Mechanism of Plastic Deformation: Slips, defects, plastic deformation on atomic scale.
2. Machining Process : [2.5 Lectures]
Types of machining processes; Chip formation; Orthogonal and Oblique Cutting; Types of Chips; Built-up edge formation.
3. Tool Geometry : [4 Lectures]
Reference planes; Tool specification: American System (ASA), continental or Orthogonal System (ORS), International or Normal Rake system (NRS); Tool angle relationships in ORS, ASA and NRS; Selection of Tool Angles; Multiple-point cutting tools: twist drill, helical milling cutter.
4 . Mechanics of Metal Cutting : [4.5 Lectures]
Merchant's Circle Diagram; Co-efficient of Friction: Determination of stress, strain and strain rate; Measurement of shear angle; Thin Zone model: Lee and Shaffer's Relationship; Thick Zone model: Okushima and Hitomi Analysis
5. Friction in Metal Cutting : [3 Lectures]
Nature of sliding friction; Friction in Metal Cutting: Sticking and Sliding Zones, Analysis of
Stress Distribution on the tool face: Zorev’s model; Determination of mean angle of friction.
6. Mechanism of Oblique cutting : [5 Lectures]
Rake angles in oblique cutting: Analytical determination of Normal Rake angle, velocity rake angle and effective rake angle; their relationship; shear angles in oblique cutting; velocity relationship; Force relationships in oblique cutting.
7. Practical Machining Operations : [3.5 Lectures]
Turning, shaping and planning, Slab milling, Drilling: Machining Parameters, force magnitudes, power consumption, material removal rate, time per pass.
8. Measurement of cutting Forces : [2 Lectures]
Basic methods of measurement: Axially Loaded members, Cantilever Beam, Rings and Octagon, dynamometer requirements; machine tool dynamometers.
9. Laboratory experiments on turning and grinding : [3 Lectures]
Tool angles; Measurement of cutting forces in turning and grinding; Measurement of temperature; chip thickness ratio; grain concentration in grinding.
9. Tool Material, Tool Wear and Tool Life : [4 Lectures]
Types of tool wear; Mechanisms of wear: Abrasion, Adhesion and Diffusion. Progressive tool wear: flank and crater wear. Tool Life: variables affecting tool life - cutting conditions, tool geometry, Types of tool materials, fabrication of cutting inserts, coatings, work material and cutting fluid; Machinability and their criteria.
10. Economic of Machining : [2.5 Lectures]
Minimum Production Cost Criterion; Maximum Production Rate Criterion, and Maximum Profit Rate Criterion. Restrictions on cutting conditions: maximum power restriction, speed restriction, force and vibration restriction, surface finish restriction.
11. Thermal Aspects of Machining : [2 Lectures]
Distinct regions of heat generation; Equations of Heat Flow: heat Flow due to conduction, heat flow due to transportation, heat absorbed and heat generated; Average Shear Plane temperature; Average Chip-tool interface Temperature; Experimental determination of cutting temperatures.
12. Abrasive Machining Process : [3.5 Lectures]
Introduction: Types of abrasive machining processes; Grinding; types and characteristics; characteristics and specification of grinding wheels; Mechanics of Grinding Process; Determination of chip length in Grinding; Size effect; Wheel wear; Thermal Analysis; Honing and Lapping.
13. Term Paper : Submission of soft and hard copies: presentation
References:
- E.J.A. Armarego and R.H.Brown-The machining of Metals
- G Boothroyd-Fundamentals of Metal Machining and Machine tools
- A.Ghosh and Asok Mallik- Machining Science
- G.K.Lal and S.K.Choudhury-Fundamental of Manufacturing Processes
- M.C.Shaw-Metal Cuttting Principles
Journals:
- Trans. of ASME: Journal of Manufacturing Science and Engineering.
- International Journal of Machine Tools and Manufacturing.
- Annals of CIRP.
- Journal of Materials processing technology.
- Precision Engineering.
- International Journal of Mechanical Sciences.
- Proceedings, International Machine Tool Design and Research Conference.
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