3. A. MACHINING
Unit-I
Metal Cutting-
Mechanics of metal cutting. Geometry of tool and nomenclature
.ASA system Orthogonal vs. oblique cutting. Mechanics of chip
formation, types of chips. Shear angle relationship. Merchant’s
force circle diagram. Cutting forces, power required. Cutting
fluids/lubricants. Tool materials. Tool wear and tool life.
Machinability. Dynamometer. Brief introduction to machine tool
vibration and surface finish. Economics of metal cutting.
4. Unit-II
Machine Tools
(i) Lathe : Principle, construction, types, operations,
Turret/capstan, semi/Automatic, Tool layout.2
(ii) Shaper, slotter, planer : Construction, operations & drives.
1
(iii) Milling : Construction, Milling cutters, up & down
milling. Dividing head & indexing. Max chip thickness &
power required. 2
(iv) Drilling and boring : Drilling, boring, reaming tools.
Geometry of twist drills. 2
5. Unit-III
Grinding & Super finishing
(v) Grinding : Grinding wheels, abrasive & bonds, cutting
action. Grinding wheel specification. Grinding wheel wear -
attritions wear, fracture wear. Dressing and Truing. Max chip
thickness and Guest criteria. Surface and Cylindrical grinding.
Centerless grinding. 4
(vi) Super finishing : Honing, lapping, polishing.
Standardization & Interchangeability, Limits, Fits &
Tolerance and Surface roughness:
Introduction to Standardization & Interchangeability Limits,
Fits, Tolerances and IS standards, Limit-gauges, and surface-
roughness. 3
6. B. METAL JOINING
Unit-IV
(Welding)
Survey of welding and allied processes. Gas welding and
cutting, process and equipment.
Arc welding : Power sources and consumables. TIG & MIG
processes and their parameters.
Resistance welding - spot, seam projection etc. Other welding
processes such as atomic hydrogen, submerged arc, electroslag,
friction welding. Soldering & Brazing . 8
Thermodynamic and Metallurgical aspects in welding and
weld, Shrinkage/residual stress in welds. Distortions & Defects
in welds and remedies. Weld decay in HAZ. 2
7. C. NON-CONVENTIONAL MACHINING & WELDING
Unit-V
Introduction to Un-conventional Machining and Welding
Need & benefits, application and working principle of EDM,
ECM, LBM, EBM, USM. AJM, WJM. Similarly,
Non-conventional welding applications such as LBW, USW,
EBW, Plasma-arc welding, Diffusion welding, Explosive
welding/cladding.
8. Referred Books
1. Manufacturing science by Ghosh and Mallik
2. Production Technology by R.K. Jain
3. Fundamentals of metal cutting & machine tools - Juneja &
Shekhon
4. Production Engineering by P.C. Sharma
9. MACHINING
• What is machining?
• Why machining is required while other process is already exist?
• What is the significance of machining over another manufacturing
process?
13. Cutting speeds for high speed tooling
• Aluminum 600 - 2000 feet per min
• brass 500 - 1000 feet per min
• cast iron 50 - 60 feet per min
• steel [crs] 100 -180 feet per min
• steel [medium] 80 -120 feet per min
• steel [tool] 30 -50 feet per min
34. Types Of Lathe Machine
• Engine Lathe or Centre Lathe
• Wood working Lathe
• Tool Room Lathe
• Capstan & Turret Lathe
• Automatic Lathes
• CNC Lathe
35. Engine Lathe
– The most common form of lathe, motor driven and
comes in large variety of sizes and shapes.
Bench Lathe
– A bench top model usually of low power used to
make precision machine small work pieces.
Tracer Lathe
– A lathe that has the ability to follow a template to
copy a shape or contour.
36. Automatic Lathe
– A lathe in which the work piece is automatically fed and
removed without use of an operator. Cutting operations
are automatically controlled by a sequencer of some
form
Turret Lathe
– Lathe which have multiple tools mounted on turret
either attached to the tailstock or the cross-slide, which
allows for quick changes in tooling and cutting
operations.
Computer Numerical Controlled (CNC) Lathe
– A highly automated lathe, where both cutting, loading,
tool changing, and part unloading are automatically
controlled by computer coding.
40. Various Cutting Operations
• Turing – produces straight, conical, curved, or grooved workpieces
• Facing – produces a flat surface at the end of the part
• Boring – to enlarge a hole
• Drilling - to produce a hole
• Cutting off – to cut off a work-peiece
• Threading – to produce threads
• Knurling – produces a regularly shaped roughness
41. Lathe Specifications
• A lathe is specified by its
– Swing – maximum diameter of the workpiece
– Distance from headstock and tailstock centers
– Length of the bed
42. How to use lathe tools
• When working on the lathe make sure the tool rest is on securely.
• When you are using a lathe tool do not use to much pressure, using the
lathe is more of an angles game than a who has more strength.
• If you push to hard on a lathe tool than it will stick on the wood and the
project could possibly stop or fly off of the lathe injuring you or your
fellow workers.
• You also want to make sure your tool is not pointed to far down, you
want your tool to be pointed up to maximize your cut accuracy.
46. The Shaper Machine
• One of the most common and useful m/c found in the machine shop is the
shaper.
• The shaper is used primarily for machining flat surfaces with a single point
tool.
• Many operations such as cutting external and internal key-way, dovetail, T-
slots, gear racks, grooves, and miscellaneous shapes can be machined on the
shaper.
• In this machine, the cutting tool reciprocates or moves backward and
forward.
• The main functions of shaping machines are to produce flat surfaces in
different planes.
.
55. Operation performed on shaper machine
• The first step in machining a job is to mount the job on the
shaper-table and clamp it tightly in the vice or on the table by
means of T-bolts etc.
• The second step is to adjust the stroke of ram according to the
length of work piece. The ram stroke is kept about 60–70 mm
longer than job.
• A tool is now selected and clamped in the tool post.
• The depth of cut is given by rotating the hand wheel and
lowering the tool slide.
• Table height is adjusted only at the time of fixing the job
according to the height of job. Feed is given by shifting the
table laterally.
• The feed is given during the return stroke of ram.
60. Milling Machines
Milling is another basic machining process by which
surface is generated progressively by the removal of
chips from a work piece as it is fed a rotating cutter.
61. Purpose of Milling tool
• Flat surface in vertical, horizontal and inclined planes
• Making slots or ribs of various sections
• Slitting or parting
• Making helical grooves like flutes of the drills
• Cutting teeth in piece or batch production of spur gears,
straight toothed bevel gears, worm wheels, sprockets,
clutches etc.
• Producing some salient features like grooves, flutes,
gushing and profiles in various cutting tools, e.g., drills,
taps, reamers, hobs, gear shaping cutters etc.
62. Principle parts of Milling Machine
• Base: It is foundation of machine tool and is
that part upon which all others parts are
mounted.
• Column:
– the motor and other driving mechanism are
contained within it.
– It supports and guides the knee in its vertical
travel.
63. • Knee:
– the knee projects from the column and slides up
and down on its face.
– It supports the saddle and table and is partially
supported by the elevating screw adjust its height.
• Table :
– Rest on ways on the saddle
– Travels longitudinally in a horizontal plane.
– It supports fixture the fixture and workpiece.
65. • Over arm:
– the over arm is mounted and guided by the arm.
– Support the spindle or Arbor.
• Spindle :
– Obtain power from motor, gear , clutch etc.
– Transmit this power to Arbor.
– Cutters are mounted directly in the nose.
• Saddle : The saddle supports and carries the
table and is adjustable transversely on ways
on top of the knee.
66.
67. Classification of Milling Machines
(1) Column and knee type milling machines
(a) Horizontal milling machines
(b) Vertical milling machines
(c) Ram type milling machines
(d) Universal milling machines
(2) Bed type milling machines
(a) Manufacturing or fixed bed type milling
machines
(b) Horizontal bed type milling machines
(c) Vertical bed type milling machines
68. (3) Planer type milling machines
(4) Special purpose milling machines
(a) Rotary table milling machines
(b) Drum type milling machines
(c) Tracer controlled milling machines
(d) Thread milling machine
(e) Key-way milling machine
(f) Skin and spar milling machine
75. TYPES OF SHAPERS
Three types of shapers commonly found in a machine shop are
1 . crank, 2. gear, & 3. hydraulic
The size of a shaper is determined by the largest cube which it can m/c.
1.CRANK SHAPER
• Most commonly used.
• Its ram is given reciprocating motion by means of a rocker arm operated by a crank
pin from the main driving gear, or "bull wheel."
• The forward stroke of the shaper occurs when the crank pin is in the upper portion
of the rocker arm
• The lower portion .
ENGINEERING
Return stroke occurs when the pin is in the • The return stroke to be faster than the
forward stroke on a 3:2 ratio.
