Manufacturing Processes- Machining Processes

Manufacturing
Technology
UNIT
4

UNIT
1
Mr. Kiran
Wakchaure
Manufacturing Technology SANJIVANI COLLEGE OF ENGINEERING, KOPARGAON
Manufacturing Technology
Course
Outcome
Statements Bloom’s Taxonomy
CO1 Classify and compare different materials based on their properties to
select appropriate materials for specific manufacturing applications.
2 Understand
CO2 Design and optimize casting processes for the manufacturing of high-
quality components using knowledge of materials, process parameters,
and quality control techniques.
3 Apply
CO3 Select and optimize metal forming processes for specific applications using
knowledge of process parameters, material properties, and tool design.
3 Analyse
CO4 Analyze and optimize metal cutting processes for efficiency, quality, and
cost-effectiveness using knowledge of cutting tools, machine tools, and
cutting parameters.
3 Apply
CO5 Select and optimize joining processes for specific applications using
knowledge of materials, joint design, and welding parameters.
3 Apply
CO6 Evaluate and select appropriate advanced manufacturing processes for
specific applications using knowledge of process capabilities, limitations,
and economic feasibility.
3 Evaluate

Manufacturing technology refers to the tools, techniques, and processes used in the
production of goods, including the design, development, and manufacturing of products.
It involves the application of various technologies, such as engineering, materials
science, computer science, and management science, to create products in an efficient,
effective, and cost-effective manner.
The goal of manufacturing technology is to produce products that meet the customer's
requirements and expectations while maximizing efficiency, productivity, and
profitability.
UNIT
4
Mr. Kiran Wakchaure Manufacturing Technology SANJIVANI COLLEGE OF ENGINEERING, KOPARGAON
Manufacturing Technology

UNIT 4

INEFFICIENT BUT MOST IMPORTANT MANUFACTURING
PROCESS
MACHIING
CONDITIONS
M/C TOOL PRODUCT
WORK MATERAIL
CUTTING TOOL
Metal Cutting Plastic Deformation/Flow Process
Orthogonal Cutting
Oblique Cutting
Classification of Cutting
UNIT
4
Machining Processes

MATERIAL REMOVAL PROCESSES
MRPs
Traditional Advanced
Cutting Finishing
Circular
Shape
Other/Prismatic
Shape
Bonded
Abrasive
Loose
Abrasive
• Turning
• Drilling
• Boring
• Milling
• Planning
• Shaping
• Gear Cutting
• Broaching
• Grinding
• Honing
•Coated
Abrasive
• Lapping
• Polishing
Metal Cutting: Relative Motion between workpiece & cutting edge of tool
Cutting Tools: 1. Single Point tool
2. Multiple Point tool
UNIT
4

NATURE OF RELATIVE MOTION BETWEEN
THE TOOL AND WORKPIECE
UNIT
4
Machining Processes

OPERATION MOTION OF
JOB
MOTION OF
CUTTING
TOOL
FIGURE OF
OPEARTION
TURNING ROTARY TRANSLATORY
(FORWARD)
BORING ROTATION TRANSLATION
(FORWARD)
DRILLING FIXED (NO
MOTION)
ROTATION AS
WELL AS
TRANSLATOR
Y FEED
UNIT
4
Machining Processes

PLANING TRANSLATORY INTERMITTENT
TRANSLATION
MILLING TRANSLATORY ROTATION
GRINDING ROTARY /
TRANSLATORY
ROTARY
WHAT IS THE BASIC DIFFERENCE BETWEEN ?
TURNING
BORING
PLANING
DRILLING
MILLING
GRINDING
• SINGLE VS MULTI POINT
•CONTINUOUS AND
INTERMITTENT
AND

Fundamentals of Cutting
Examples of cutting processes.
Figure: Basic principle of the turning operations.
Figure: Two-dimensional cutting
process, also called orthogonal
cutting. Note that the tool shape
and its angles, depth of cut, to, and
the cutting speed, V, are all
independent variables.
UNIT
4
Machining Processes

Types of Cutting
o Orthogonal Cutting (2-D Cutting):
Cutting edge is (1) straight, (2)parallel to the original plane surface on the
work piece and (3)perpendicular to the direction of cutting. For example:
Operations: Lathe cut-off operation, Straight milling, etc.
o Oblique Cutting (3-D Cutting):
Cutting edge of the tool is inclined to the line normal to the cutting
direction. In actual machining, Turning, Milling etc. / cutting operations are
oblique cutting(3-D)
ORTHOGONAL CUTTING
OBLIQUE CUTTING
UNIT
4
Machining Processes

Factors Influencing Cutting Process
PARAMETER INFLUENCE AND INTERRELATIONSHIP
CUTTING SPEED,
DEPTH OF CUT, FEED,
CUTTING FLUIDS
FORCES, POWER, TEMPERATURE RISE, TOOL LIFE,
TYPE OF CHIP
, SURFACE FINISH.
TOOL ANGLES
CONTINUOUS CHIP
BUILT-UP EDGE CHIP
AS ABOVE, INFLUENCE ON CHIP FLOW DIRECTION,
RESISTANCE TO TOOL CHIPPING.
GOOD SURFACE FINISH; STEADY CUTTING FORCES;
UNDESIRABLE IN AUTOMATED MACHINERY.
POOR SURFACE FINISH, THIN STABLE EDGE CAN
PROTECT TOOL SURFACES.
DISCONTINUOUS
CHIP
DESIRABLE FOR EASE OF CHIP DISPOSAL;
FLUCTUATING CUTTING FORCES; CAN AFFECT
TEMPERATURE RISE
SURFACE FINISH AND CAUSE VIBRATION AND
CHATTER.
INFLUENCES TOOL LIFE, PARTICULARLY CRATER
WEAR, AND DIMENSIONAL ACCURACY OF
WORKPIECE; MAY CAUSE THERMAL DAMAGE TO
TOOL WEAR DIMENSIONAL
FORCES AND
WORKPIECE SURFACE.
INFLUENCES SURFACE FINISH,
ACCURACY
, TEMPERATURE RISE,
POWER.
TOOL WEAR
MACHINABILITY
RELATED TO TOOL LIFE, SURFACE FINISH, FORCES
AND POWER
UNIT 4

13
Machining = Chip formation by a tool
UNIT 4

14
Big lathe with big chips
UNIT 4

15
Discontinuous chips
UNIT 4

16
Continuous chips
UNIT 4

Machine Tools and Processes
• Turning
• Boring
• Milling
• Planing
• Shaping
• Broaching
• Drilling
• Filing
• Sawing
• Grinding
• Reaming
• Honing
• Tapping
UNIT 4

Classification of Conventional Machining
• Cutting processes
– Single point: e.g. shaping, planing, turning, boring, etc.
– Multiple point: e.g. milling, drilling, etc.
• Abrasive processes
– Grinding, honing, etc.
UNIT 4

19
Lathe (for turning)
UNIT 4

20
Lathe Parts
UNIT 4

21
Typical Insert Cutting Tool
insert
holder
UNIT 4

22
UNIT 4

23
Boring
UNIT 4

Old Boring Machine
UNIT 4

25
Shaper
UNIT 4

Trepanning
UNIT 4

27
Drilling
(a)
UNIT 4

28
Milling
UNIT 4

29
Face Milling
UNIT 4

Thread Tap and Die
internal external

Mechanics of Chip Formation
(a) Basic mechanism of chip formation in metal cutting. (b)
Velocity diagram in the cutting zone.
V=> Cutting velocity, Vs= Shear velocity, Vc=Chip velocity
Φ= Shear angle, α=Rake angle

Theory of Metal Cutting
• Metal cutting or Machining is the process of producing
workpiece by removing unwanted material from a block
of metal, in the form of chips.
• This process is most important since almost all the
products get their final shape and size by metal removal,
either directly or indirectly.
• The major drawback of the process is loss of material in
the form of chips.

THE MECHANICS OF CHIP FORMATION

THE MECHANICS OF CHIP FORMATION
• A wedge shaped tool is made to move relative to the
workpiece. As the tool makes contact with the metal
exerts a pressure on it resulting in the compression of the
metal near the tool tip.
• This induces shear-type deformation within the metal and
it starts moving upward along the top face of the tool. As
the tool advances, the material ahead of it is sheared
continuously along a plane called the Shear plane.
• This shear plane is actually a narrow zone (of the order of
about 0.025 mm) and extends from the cutting edge of
the tool to the surface of the workpiece.

Theory of Metal Cutting
• The cutting edge of the tool is formed by two intersecting
surfaces. The surface along which the chip moves upwards
is called “Rake surface” and the other surface which is
relieved to avoid rubbing with the machined surface, is
called “Flank”.
• The angle between the rake surface and the normal is
known as “Rake angle” (which may be positive or negative),
and the angle between the flank and the horizontal
machined surface is known as the “relief or clearance
angle”. Most cutting processes have the same basic features
as in Fig. , where a single point cutting tool is used (a milling
cutter, a drill, and a broach can be regarded as several
single-point tools joined together and are known as multi-
point tools)

MECHANICS OF CHIP FORMATION
 Plastic deformation along shear plane
(Merchant)
 The fig. where the work piece remains
stationary and the tool advances in to the work
piece towards left.
 Thus the metal gets compressed very severely,
causing shear stress.
 This stress is maximum along the plane is
called shear plane.
 If the material of the workpiece is ductile, the
material flows plastically along the shear plane,
forming chip, which flows upwards along the
face of the tool.
 The tool will cut or shear off the metal, provided
by;
•The tool is harder than the work metal
•The tool is properly shaped so that its
edge can be effective in cutting the
metal.
•Provided there is movement of tool
relative to the material or vice versa, so
as to make cutting action possible.
Fig: Shear Plane
Primary shear
zone (PSDZ)
Secondary shear
deformation zone
(SSDZ)
Fig: Shear deformation
zones
Fig: Shaping
operation
Fig: Shear deformation
zones

tc tc
sin
sin
ABC & ABD
tu
AB 
also, AB  
sin(90  ( )) cos( )
tu

tc cos( )
tc :Chip thickness
tu :Uncut chip thickness
Vf :Chip Sliding Velocity
Vs : Shear Velocity
Vc :Cutting Velocity
 : Shear Angle
Fig: Schematic of Geometry of chip formation
Geometry of chip Formation:
φ
90-ф+α = 90-(ф-α)

(= feed) and α are already
How to determine φ & rc ?
tc should be determined from the chip. tu
known.
c
c
t
rc sin
r 
tu
:Chip thickness Ratio /Coeffinicient
1

coscos  sinsin
1 rccotcos  rcsin
rccos  (1 rc sin) tan
cos 
 tan 
 rc
1 r sin 
 c 
φ
90-ф+α
= 90-(ф-α)
Substitute the value of tu /tc
from earlier slide and simplify to get:
SHEARANGLEAND CHIPTHICKNESS RATIO EV
ALUATION
To determine tc with micrometer, is difficult and not so because of
uneven surface. How? (say, f=0.2 mm/rev. An error of even 0.05 mm will cause
an error of 25 % in the measurement of tc)
Volume Constancy ConditionDr
.:V
.VK.joailnu,I
I
m
TK
ea
n
p
ou
fr Uncut chip = Volume of cut chi3p

Lutub  Lctcb
Lctc  Lutu
c
c u
t L
or,r 
tu 
Lc
Lc = Chip length
Lu = Uncut chip length
b = Chip width
(2-D Cutting)
SHEARANGLEAND CHIPTHICKNESS RATIO EV
ALUATION
LENGTHOF THE CHIP MAY BE MANY CENTIMETERS HENCE THE ERROR IN
EVALUTION OF rc WILLBEC OMPARATIVELYMUCH LOWER.
(rc = Lc / Lu)
4

Clearance Angle
Work
Tool
Chip
Ft
Fc
F
N
Fs
α
α
β
∅
Fn
R
79
α
G
E
A
B
∅
D
F
α
Δ FAD = (β - α)
Δ GAD = φ + (β - α)
FORCE CIRCLE DIAGRAM

Forces in Orthogonal Cutting:
•Frictionforce,F
•ForcenormaltoFrictionforce,N
•CuttingForce, FC
•Thrustforce,Ft
• ShearForce, FS
•ForceNormal toshearforce, Fn
•Resultantforce,R
Force Analysis

F  Ft cos  Fc sin
N  Fc cos  Ft sin
Coefficient of Friction ()
cos  Fc sin
  tan  
F

Ft
N Fc cos  Ft sin
  Friction Angle
 
Ft
 Fc tan
Fc  Ft tan
also,   tan1
()
FORCEANAL
YSIS
Dr
. V
.K.jain, IIT Kanpur
DIVIDE R.H.S. BY Cos α

FN  Ft cos  Fc sin
also,
FC  R cos( )
FS  R cos(   )

FC

cos( )
FS cos(   )
S
ShearPlaneArea (A ) 
tub 
 b

tu
sin  sin 
 
Foce Analysis
FS  Fc cos  Ft sin
Δ FAD = (β - α)
Δ GAD = φ + (β - α)

Let  be the strength of work material
t b

u
sin
FS  AS 
C
F 
 tub  cos( ) 
 sin  cos(   ) 
  
and, 1 
R 
 tub 


 sin   cos(   ) 
   
u
t
t b
sin
F  R sin( )  
sin( )
cos(   )
Ft
Fc
 tan( )
Foce Analysis

chip
S
A
) 
FS
Mean Shear Stress (t
(On Chip)

(Fc cos  Ft sin)sin
b tu
chip
S
A
) 
FN
Mean Normal Stress (
(On Chip)
=
(Ft cos  Fc sin)sin
b tu
Foce Analysis

VELOCITY ANALYSIS
Vc :Cutting velocity of tool relative to workpiece
Vf :Chip flow velocity
Vs : Shear velocity
Using sine Rule:
Vc

Vf

Vs
sin(90( )) sin sin(90)
Vc Vs

Vf

cos( ) sin cos
f c c
and V  V r
Vc sin
cos( )
s
c
V 
Vc cos 
Vs

cos
cos( ) V cos( )
11

Shear Strain & Strain Rate
Two approaches of analysis:
Thin Plane Model:- Merchant, PiisPanen, Kobayashi & Thomson
Thick Deformation Region:- Palmer, (At very low speeds) Oxley, kushina,
Hitoni
Thin Zone Model: Merchant
ASSUMPTIONS:-
• Tool tip is sharp, No Rubbing, No Ploughing
• 2-D deformation.
• Stress on shear plane is uniformly distributed.
• Resultant force R on chip applied at shear plane is equal, opposite and
collinear to force R’ applied to the chip at tool-chip interface. 12

Expression for Shear Strain
The deformation can be idealized as a process of block slip (or preferred
slip planes)
Length
ShearStrain() 
deformation
 
s

AB

AD

DB
y CD CD CD
 tan( )  cot
sin( )sin  cos cos( )
,
sin cos( )
 
cos
sin cos( )
Dr
. V
.K.jain, IIT Kanpur

Shear angle relationship
• Helpful to predict position of shear plane (angle φ)
• Relationship between-
Shear Plane Angle (φ)
Rake Angle (α)
Friction Angle(β)
Several Theories
Earnst-Merchant(Minimum Energy Criterion):
Shear plane is located where least energy is required for shear.
Assumptions:-
• Orthogonal Cutting.
• Shear strength of Metal along shear plane is not affected by
Normal stress.
• Continuous chip without BUE.
• Neglect energy of chip separation. Dr
. V
.K.jain, IIT Kanpur 15

Condition for minimum energy,
dFc
d
 0
u
dFc
d
 t b cos ( )
cos cos(   ) sin sin(   )
 
sin2
 cos2
(   )
 
 0
cos cos(   ) sinsin(   )  0
cos(2   )  0
2
2    

 
 
1
( )
4 2
Shear angle relationship
Assuming No Strain hardening:
Dr
. V
.K.jain, IIT Kanpur 60

Tool Nomenclature/Angles
Side Cutting Edge Angle (SCEA).
• Side cutting edge angle, Cs, also known as lead angle, is the angle
between the side cutting edge and the side of the tool shank.
• It is the angle which prevents interference as the tool enters the work
materials.
• The tip of the tool is protected at the start of the cut, Fig. , as it enables
the tool to contact the work first behind the tip.
• Satisfactory values of SCEA vary from 15° to 30°, for general machining

End Cutting Edge Angle (ECEA).
• This is the angle between the end cutting edge and a line normal to the
tool shank.
• Ce. The ECEA provides a clearance or relief to the trailing end of the
cutting edge to prevent rubbing or drag between the machined surface
and the trailing (non-cutting) part of the cutting edge
• An angle of 8° to 15° has been found satisfactory in most cases on side
cutting tools

Side Relief Angle (SRA).
It is the angle between the portion of the side flank immediately below the
side cutting edge and a line perpendicular to the base of the tool, and
measured at right angle to the side flank.
These angles (denoted 𝜃𝑠 ) are provided so that the flank of the tool clears
the workpiece surface and there is no rubbing action between the two.
Relief angles range from 5° to 15° for general turning

End Relief Angle (ERA).
It is the angle between the portion of the end flank immediately below
the end cutting edge and a line perpendicular to the base of the tool, and
measured at right angle to the end flank.
These angles (denoted 𝜃𝑒 ) are provided so that the flank of the tool clears
the workpiece surface and there is no rubbing action between the two.
Relief angles range from 5° to 15° for general turning

Back-Rake Angle (BRA).
It is the angle between the face of the tool and a line parallel to the base
of the tool and measured in a plane (perpendicular) through the side
cutting edge.
The top face of the tool over which the chip flows is known as the rake
face. The angle which this face makes with the normal to the machined
surface at the cutting edge is known as “Back-rake angle, 𝛼𝑏 ”,

Side -Rake Angle (SRA).
The angle between the face and a plane parallel to the tool base and
measured in a plane perpendicular to both the base of the tool holder and
the side cutting edge, is known as “Side-rake angle, 𝛼𝑠 ”. The rake angles may
be positive, zero, or negative.
Cutting angle and the angle of shear are affected by the values for rake
angles. Larger the rake angle, smaller the cutting angle (and larger the shear
angle) and the lower the cutting force and power. However, since increasing
the rake angle decreases the cutting angle, this leaves less metal at the point
of the tool to support the cutting edge and conduct away the heat

Side-Rake Angle (SRA). It is the angle between the tool face and a line
parallel to the base of the tool and measured in a plane perpendicular to
the base and the side cutting edge
Larger the rake angle, smaller the cutting angle (and larger the shear
angle) and the lower the cutting force and power. However, since
increasing the rake angle decreases the cutting angle, this leaves less metal
at the point of the tool to support the cutting edge and conduct away the
heat.

Nose Radius.
Nose radius is favourable to long tool life and good surface finish. A sharp
point on the end of a tool is highly stressed, short lived and leaves a
groove in the path of cut. There is an improvement in surface finish and
permissible cutting speed as nose radius is increased from zero value.
Too large a nose radius will induce chatter. The use of following values for
nose radius is recommended :
R = 0.4 mm, for delicate components. 1.5 mm for heavy depths of cut,
interrupted cuts and heavy feeds. = 0.4 mm to 1.2 mm for disposable
carbide inserts for common use. = 1.2 to 1.6 mm for heavy duty inserts.

American Standards Association System (ASA) or American National Standards Institute (ANSI).

(a)
(c)
(b)
Fig: Turning Operations
UNIT 4

Right-Hand Cutting Tool
Figure 20.10 (a) Schematic illustration of a right-hand cutting tool.
Although these tools have traditionally been produced from solid tool-
steel bars, they have been largely replaced by carbide or other
inserts of various shapes and sizes, as shown in (b). The various
angles on these tools and their effects on machining are described in
Section 22.3.1.
UNIT 4

Types of Chips
 Continues Chips
 Discontinues Chips
 Continuous Chips
with Built up Edge (BUE)
Conditions for Continuous
Chips:
• Sharp cutting edges
• Low feed rate (f)
• Large rake angle ()
• Ductile work material
• High cutting speed (v=)
• Low friction at Chip-Tool interface
CHIP FORMATION
Fig; Schematic of chip
formation
Fig; Schematic of different types of chip
UNIT 4

Types of Chips
(a) Continuous chip
with narrow,
straight primary
shearzone;
(b) Secondary shear
zone at the chip-
toolinterface;
(c) Continuous chip
withbuilt-upedge
(d) Continuous chip
with large primary
shearzone
(e) Segmented
or
nonhomogeneous
chipand
(f) Discontinuous
chip.
(f)
(b)
(a) (c)
(d) (e)
Source:After M.C.Shaw,P
.K.Wright,andS.Kalpakjian.
UNIT 4

Built-Up Edge Chips
(b)
(c)
(a)
Built-up edge (BUE) is a common type of chip formation that occurs during metal cutting processes. It is a
localized accumulation of material on the cutting tool edge that is formed due to the high temperatures and
pressures generated during cutting.
BUE is typically observed in machining operations that involve ductile materials such as aluminum and
copper, and it can also occur in steel cutting under certain conditions. The formation of BUE can result in a
number of issues such as increased cutting forces, tool wear, surface finish problems, and reduced
accuracy of the machined part.
To prevent or minimize BUE formation, various strategies can be employed such as reducing cutting
speeds and feeds, optimizing cutting tool geometry and material selection, using lubricants or coolants,
and ensuring proper machine setup and maintenance.
TURNING LAY
MILLING LAY
UNIT 4

Continuous chip Results in:
• Good surface finish
• High tool life
• Low power consumptions
Discontinuous Chip:
Chip in the form of discontinuous segments:
 Easy disposal
 Good surface finish
Conditions for discontinuous chips:
• Brittle Material
• Low cutting speed
• Small rake angle
Built up Edge:
Conditions for discontinuous chips:
High friction between Tool & chip
Ductile material
Particles of chip adhere to the rake face of the tool near cutting edge
UNIT 4

Chip- Breaking
• The chip breaker break the produced chips into small pieces.
• The work hardening of the chip makes the work of the chip breakers
easy.
• When a strict chip control is desired, some sort of chip breaker has to be
employed.
• The following types of chip breakers are commonly used:
a)
b)
c)
d)
Groove type
Step type
Secondary Rake type
Clamp type
Fig: Schematics of different types of chip barkers
UNIT 4

Chip Breakers
(a) Schematic illustration of the action of a chip breaker. Note that the chip
breaker decreases the radius of curvature of the chip. (b) Chip breaker
clamped on the rake face of a cutting tool. (c) Grooves in cutting tools
acting as chip breakers.
UNIT 4

Examples of Chips Produced in Turning
Various chips produced in turning: (a) tightly curled chip; (b) chip hits
workpiece and breaks; (c) continuous chip moving away from workpiece;
and (d) chip hits tool shank and breaks off. Source: G. Boothroyd, Fundamentals of Metal
Machining and Machine Tools. Copyright © 1975; McGraw-Hill Publishing Company.
UNIT 4

Types of Cutting
o Orthogonal Cutting (2-D Cutting):
Cutting edge is straight, parallel to the original plane surface at
the work piece and perpendicular to the direction of cutting.
E.g. Operations:
• Lathe cut-off tools
• Straight milling cutters etc.
o Oblique Cutting:
Cutting edge of the tool is inclined to the line normal to the
cutting direction. In actual machining, Turning, Milling etc/ cutting
operations are oblique cutting(3-D
UNIT 4

Forces in Two-Dimensional Cutting
/ Orthogonal Cutting
Forces acting on a cutting tool in two-dimensional cutting.
Note that the resultant force, R, must be collinear to balance the forces.
UNIT 4

Cutting With an Oblique Tool
(a)Schematic illustration of cutting with an oblique tool.
(b)Top view showing the inclination angle, i.
(c)Types of chips produced with different inclination.
UNIT 4

Flank and Crater Wear
(e)
(d)
(a) (b) (c)
(a) Flank and crater wear in a cutting tool. Tool moves to the left.
(b) View of the rake face of a turning tool, showing nose radius R and crater wear
pattern on the rake face of the tool.
(c) View of the flank face of a turning tool, showing the average flank wear land VB
and the depth-of-cut line (wear notch).
(d) Crater and (e) flank wear on a carbide tool. Source: J.C. Keefe, Lehigh University.
UNIT 4

Mechanics of Metal Cutting
UNIT 4

85
Turning -MRR
UNIT 4

86
Turning
Average cutting speed, Vavg = DavgN
Davg is the average diameter of workpiece
N is the spindle speed in rpm
Material removal rate, MRR = Vavgdf
d is the depth of cut
f is the feed (units: mm/rev or in/rev)
Cutting power, Pc = ucMRR=FcV
Fc=Cutting force
V = Cutting speed
Machining time, tm = L/(fN) = L/F
F is the feed rate (units: mm/min or in/min)

v
N1  500RPM
f1  0.15mm / rev
d1  0.3mm
CuttingSpeed , Vc  .R
Vc  1308.9mm / sec
M RR  58.905 mm 3
/ sec
D1
L
Depth of cut
Feed
N1
W/P
Tool
Turning operation
Problem-1:
A turning operation has to be performed on an aluminum rod of diameter50 mm and
length 300mm. The Spindle speed of lathe is given to be 500 RPM. The feed and depth of
cut are 0.15mm/rev and 0.3 mm respectively. Draw a neat sketch of the turning
operation described above. Find out the cutting speed in mm/s and the volumetric
material removal rate (MRRv).
Solution:
M R Rv  Vc  f1  d1

60
c
v
V
N1  500RPM
f1  0.15mm / rev
d1  0.3mm
CuttingSpeed , Vc  .R
  500     50
 
Vc  1308.9mm / sec
M RRv    D1  N1  f1  d1
M RRv  Vc  f1  d1
M RRv  1308.9  0.15  0.3
M RR  58.905 mm 3
/ sec
D1
L
Depth of cut
Feed
N1
W/P
Tool
Turning operation
Problem-1:
A turning operation has to be performed on an aluminum rod of diameter50 mm and
length 300mm. The Spindle speed of lathe is given to be 500 RPM. The feed and depth of
cut are 0.15mm/rev and 0.3 mm respectively. Draw a neat sketch of the turning
operation described above. Find out the cutting speed in mm/s and the volumetric
material removal rate (MRRv).
Solution:

Milling
fr
dr
N
feed
workpiece
cutter
da

Milling Modes
Up Milling Down Milling
dr

91
Milling
Cutting speed, V = DN
D is the cutter diameter
Material removal rate, MRR = fNdadr = Fdadr
da is the axial depth of cut
dr is the radial depth of cut
f is the feed per revolution (= ftNt ; ft is the feed per cutting edge/tooth and Nt is
the number of teeth)
Cutting power, Pc = ucMRR
Machining time, tm = (L + lc)/F
lc is the length of the cutter’s first contact with the workpiece

Problem-2
An aluminum block of length 50 mm and width 70 mm is being milled using a slab milling
cutter with 50 mm diameter. The feed of the table is 15 mm/min. The milling cutter
rotates at 60 RPM in clockwise direction and width of cut is equal to the width of the
workpiece. Draw a neat sketch of the milling operation describing above conditions. The
thickness of the workpiece is 20 mm. If depth of cut of 2 mm is used then find out
cutting speed and volumetric material removal rate (MRRv).
Milling operation
N2
L
D
2
W
Feed
Milling cutter
W/P
t
W
1000
1000
60
c
v
v
V
M illing Cutter Diameter, D2  50mm
Width of cut,WOC  70mm
Depth of cut, d 2  2mm
feed , f2  15mm / min
 DN
Cutting Speed , Vc  2
m / min
  50    60   25
 
Vc  9.424m / min
M RRv  W OC  f2  d 2
M RR  70 
15
 2
MRR  35 mm3
/ sec
Solution:

Problem-2
An aluminum block of length 50 mm and width 70 mm is being milled using a slab milling
cutter with 50 mm diameter. The feed of the table is 15 mm/min. The milling cutter
rotates at 60 RPM in clockwise direction and width of cut is equal to the width of the
workpiece. Draw a neat sketch of the milling operation describing above conditions. The
thickness of the workpiece is 20 mm. If depth of cut of 2 mm is used then find out
cutting speed and volumetric material removal rate (MRRv).
Milling operation
N2
L
D
2
W
Feed
Milling cutter
W/P
t
W
1000
60
v
v
M illing Cutter Diameter, D2  50mm
Width of cut,WOC da  70mm
Depth of cut, d r  2mm
feed , f2  15mm / min
 DN
Cutting Speed , Vc  2
m / min
Vc  9.424m / min
M RRv da  f2  d r
M RR  70 
15
 2
MRR  35 mm3
/ sec
Solution:
Fdadr

Problem-3
Following the milling operation, a through hole is to be drilled on the same workpiece.
Find out the cutting speed and volumetric material removal rate if the drill of diameter 10
mm is being rotated at same RPM as in case of milling cutter with feed rate as 0.5
mm/rev.
W/P
Feed
N3
D
3
Drilling operation
Drill bit
t
3
1000
1000
4
c
v
Diameter of Drill, D  10mm
N3  60RPM
feed , f3  0.5mm / rev
Cutting Speed , V 
 N 3 D3
m / min
  60 10 
Vc   

m / min
Vc  1.884m / min  31.4mm / sec
  D 2
MRRv  3
 f3  N3
4
 102
MRRv   0.5  60
MRR  2356.19 mm3
/ min  39.27mm3
/ sec
Solution:

Examples of Wear and Tool Failures
Figure 20.18
illustrations of
(a) Schematic
types of wear
observed on various types of cutting
tools. (b) Schematic illustrations of
catastrophic tool failures. A study
of the types and mechanisms of tool
wear and failure is essential to the
development of better tool
materials.

Range of n Values for Eq. (20.20) for Various
Tool Materials
High-speed
steels Cast alloys
Carbides
Ceramics
0.08–0.2
0.1–0.15
0.2–0.5
0.5–0.7

Tool Life
Tool-life curves for a
variety of
materials.
inverse of
cutting-tool
The negative
the slope of
these curves is the
exponent n in the Taylor
tool-life equations and C
is the cutting speed at T
= 1 min.

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