First Course Handout
ME361T: Manufacturing Science & Technology
Instructor:
Dr. Supratik Mukhopadhyay, Dr. Sounak Kumar Choudhury
smukh@iitk.ac.in , choudhry@iitk.ac.in
Course Objectives:
This course is intended to provide the students with a detailed coverage of various manufacturing processes such as casting, metal forming, metal joining, traditional and advanced machining processes etc. Since the manufacturing processes are essentially multi-disciplinary in nature, attempts will be made to explain each process with the detailed mechanics and physics involved therein, so that the students can gain a sound physical insight and can apply the knowledge gained in this course into solving more complex real-world manufacturing problems.
Prerequisites:
This is a compulsory UG course for ME students, as well as double major students. Prerequisites are: TA201 and TA202.
Lecture schedule:
§ Class:
Classes will be online. Students will need to log onto the portal https://hello.iitk.ac.in/ and then, find the course ME361T. Video recorded Lectures (along with slides of the lectures in pdf format) will be uploaded every week in an asynchronous mode, which means students would be able to watch the lectures at their own time and pace.
§ Discussion hours:
There will be discussion hours to engage with the students and to clarify their doubts regarding lecture videos posted on the previous week Discussion hours will happen live over online platform ‘Zoom’ every week, unless explicitly announced. Link will be sent to you later.
Schedule: Every Monday 8.00AM-9.00AM, starting from 07.09.2020.
Grading Policy:
§ Mid-semester examination: 50%
§ End-semester examination: 50%
Course Outline (tentative):
Traditional machining processes (12 lectures)
- Introduction to Manufacturing Processes: conversion of raw material to final product; Machining operations: fabrication of various surfaces; Advantages and drawbacks of machining; Mechanism of machining; Stress, strain and plastic deformation through tensile test of a mild steel bar; Mechanism of plastic deformation; How slip occurs; Imperfections in crystal lattice structure.
- Recap on Mechanism of plastic deformation; Plastic deformation in atomic scale; The amount of shear stress necessary to affect the slip; Basic machining parameters – cutting speed, feed and depth of cut; Chip formation; Cutting tools and types of machining; Types of chips.
- Types of chips (continued); Mechanism of Built-up edge formation; Tool nomenclature: Coordinate system (ASA).
- Tool nomenclature: Coordinate system (continued); Orthogonal rake system (ORS); Normal rake system (NRS); Conversion from ASA to ORS and from ORS to NRS systems.
- Recap on conversion of tool angles; Selection of tool angles; Effect of tool angles on the cutting force and power consumption; Nose radius; Turning operation; Forces in machining.
- Forces in machining (continued); Merchant’s circle diagram: derivation of Merchant’s first equation; Shear stress and normal stress; Shear strain in chip formation; Strain rate.
- Strain rate (continued); Measurement of shear plane angle; Analytical determination of shear plane angle; Numerical examples on tool angles, Merchant’s first equation, cutting force, shear plane angle and power consumption in machining.
- Thin zone model: Lee and Shaffer relationship; Friction in metal cutting: difference between Sliding friction and friction in metal cutting; Zorev’s model for the determination of average friction along the chip-tool contact length.
- Recap on Friction in metal cutting and Zorev’s model; Practical machining operations - Turning: physical parameters, forces, material removal rate, Specific energy, power consumption and machining time; Shaping and Planing: physical parameters and forces.
- Shaping and Planing:; Drilling and Milling - physical parameters, forces, material removal rate, Specific energy, power consumption and machining time; Forces in machining; Measurement of cutting forces: Axially loaded member, Cantilever beam, ring-type structure.
- Measurement of cutting forces (continued), Ring structure, Octagon, Dynamometer requirements, Machine tool dynamometers for turning, drilling, milling and grinding; Tool wear and tool life: modes of tool failure; Mechanism of tool wear; Progressive tool wear; Taylor’s tool life equation; Variables affecting tool life – cutting parameters and tool geometry.
- Variables affecting tool life – tool and work material, cutting fluid; Numerical examples on tool life; Abrasive machining processes – Grinding wheel specifications – Abrasive type, size, grade, structure and bonding materials; Mechanics of grinding process; Specific energy Vs. Chip thickness in grinding; Grinding temperature; Economics of machining – cost analysis; Surface finish in turning, milling and grinding.
Casting (8 lectures)
- Introduction to casting; Classification; Casting processes: mould and metal details; Advantages and Disadvantages of casting; Brief historical background; Foundry practice
- Foundry practice: Video clip on steps of sand casting; Video clip on casting an iron wheel and Automated Fast Loop Moulding line; Patterns: Split, single, match-plate patterns; Shrinkage allowance
- Recap on patterns; Cope and drag patterns; Shrinkage and Machining allowances; Types of moulds: details of a sand mould; Green sand mould: properties of moulding sand: discussion.
- Recap on properties of moulding sand; Gating Design: time taken to fill up the mould; Vertical gating: aspiration effects
- Vertical gating: aspiration effects (continued); Filling time with vertical and bottom gatings; Optimum Riser Design; Heating the metal; Solidification of pure metal and alloys: Characteristic grain structure; Phase diagram; Solidification time: Chvorinov’s Rule
- Solidification time: Chvorinov’s Rule (continued); Mould constant in Chvorinov’s Rule; Shrinkage; Categories of metal casting processes; Overview of sand casting: Steps in sand casting; Making the sand mould; Desirable mould properties and characteristics; Other expendable mould casting processes
- Numerical examples on riser design; Recap on Desirable mould properties and characteristics; Shell moulding: Characteristics; Investment casting: Steps in investment casting, advantages and disadvantages; Video clip on investment casting; Multiple mould castings; Permanent mould casting
- Permanent mould casting (continued), steps, advantages and disadvantages, applications; Die casting: cold and hot chamber die casting
Welding (3 lectures)
- Introduction to welding Processes
- Types of welding processes-Fusion, solid state and solid/liquid state joining
- Characteristics of arc welding
- Metal transfer, meting rates and arc control
- Heat flow in welds
- Residual stresses, metallurgical changes
- Discussion on some classical welding processes
- Weld defects and inspection.
Bulk deformation processes (10 lectures)
- Introduction to forming, stress-strain curves, plasticity, yield criteria
- Introduction to flat rolling
- Mechanics of flat rolling, force, power and torque estimation
- Other classical rolling processes, rolling defects
- Introduction to wire drawing
- Mechanics of wire drawing, power and allowable reduction
- Wire drawing defects
- Introduction to forging
- Mechanics of open-die forging process
- Other forging processes, forging defects
- Introduction to deep drawing
- Deep drawing mechanics
- Deep drawing defects
Non-traditional machining processes (10 lectures)
- Electrochemical machining process
- Electric discharge machining process
- Ultrasonic machining process
- Electron beam/Laser beam machining (only If time permits)
Metrology (2 lectures)
- Importance of measurements
- Limits, fits, tolerances, shaft and hole basis system
- Characterization of a surface (Rmean, Rz, Rrms)
Attendance:
Students must attend 100% of classes. The attendance (login time and duration) would be monitored through the online portal.
Reference books:
Supporting reference books/material will be mentioned in the online lecture material provided.