This presentation provides an insight to the topic of milling machines and its basics. It will be of great help for the beginners who would be trying to grasp the concepts related to this topic.

1. MILLING MACHINEMILLING MACHINE

2. Types of Milling Machine
FIGURE (a) Schematic illustration of a horizontal-
spindle column-and-knee-type milling machine.
(b) Schematic illustration of a vertical-spindle
column-and-knee-type milling machine.

3. INTRODUCTION
Working Principle: The work is rigidly clamped on the
table of Milling Machine, or held between the centres, and
revolving Multiteeth cutter mounted either on a spindle or an
Arbor. The cutter revolves at a fairly high sped and the work fed
slowly past the cutter. The work can be fed in a vertical,
longitudinal or cross direction. As the cutter teeth remove the
metal from the work surface to produce the desire shape.

4. Types of Milling Machine
Types of Milling Machine
A large variety of different types of Milling machines are available
and it is really difficult to account for all these types. The broad
classification of these machines can be done as follows:
 Column and Knee type Milling Machine
 Fixes Bed type or Manufacturing type Milling Machine
 Planer type Milling Machine
 Production type Milling Machine
 Special purpose Milling Machine

5. Column and Knee Type Milling Machines:
These Machines are all General Purpose Milling Machines
and have Single Spindle only. They derive their name
“Column and Knee Type” from the fact that the work table
is supported on a Knee like casting, which can be slide in
a vertical direction along a vertical column. These
machines depending upon the spindle position and table
movements, are further classified as follows.
(a)Hand Milling Machine
(b)Plain or Horizontal Milling Machine
(c)Vertical Milling Machine
(d)Universal Milling Machine and
(e)Omniversal Milling Machine

6. Fixed Bed Type or Manufacturing Type Milling Machine:
These machines in a comparison to the Column and Knee
Type, are more sturdy and rigid, heavier in weight and
larger in size. They are not suitable for Tool Room Work.
Most of these machines are either Automatic or semi
automatic in operation. They carry single spindle or multiple
spindles. The common operations performed on these
machines are Slot Milling, Grooving, Gang Milling and
Facing. Also they facilitate machining of many jobs together,
called Multi-piece Milling. They are classified as follows:
(a)Plain Type (having single horizontal spindle)
(b)Duplex Head ( having double horizontal spindles)
(c)Triplex Head (having two horizontal and one vertical
spindle)
(d)Rise and Fall Type (for profile Milling)

7. Planer Type Milling Machine:
They are used for heavy work. Up to a maximum of Four
Tool Head can be mounted over it, which can be adjusted
vertically and transverse directions. It has a robust and
massive construction like a Planer.
Production Milling Machines:
They are also manufacturing type but differ from above
machines in that they do not have a Fixed Bed and are
including following Machines:
(a)Rotary Table or Continuous Type
(b)Drum Type and
(c)Tracer Controlled

8. Special Purpose Milling Machines:
These machines are designed to perform a specific type of
Operations only. They include the following machines:
(a)Thread Milling Machine
(b)Profile Milling Machine
(c)Gear Milling or Gear Hobbing Machine
(d)Cam Milling Machine
(e)Planer Type Milling Machine
(f)Double end Milling Machine
(g)Skin Milling Machine and
(h)Spar Milling Machine
However the most commonly used milling machine in tool room
and machine shop are Column and Knee type and hence we will
discuss Column and Knee Type Milling machineColumn and Knee Type Milling machine only in this
chapter .

9. Column and Knee Type Milling Machines:
Hand Milling Machine:
It is the simplest of all the Milling Machine and smallest in
size. All the operations except the rotation of the Arbor, are
performed by hand. The table carrying the work over it, is
moved by hand to feed the work. This machine is specially
useful in producing small components like Hexagonal or
Square Heads on Bolts, cutting slots on screw heads, cutting
key ways etc.

10. Plain or Horizontal Milling Machine:
The machine is shown in the figure.
The vertical column serves as a
housing for electricals, the Main
drive, spindle bearings etc. The knee
act as a support for Saddle,
Worktable and other accessories like
indexing head etc. Overarm provides
support for the yoke which in turn,
supports the free end of the Arbor.
The arbor carrying the cutter rotates
about the horizontal axis.
The table can be given straight motions in three directions;
longitudinal, cross and vertical (up and down) but can not be
swivelled.

11. For giving vertical movement to the table and knee itself,
together with the whole unit above it, slides up and down
along the ways provided in front of the column. For giving
the cross movement to the table, the saddle is moved
towards or away from the column alongwith the whole unit
above it. A Brace is employed to provide additional support
and rigidity to the arbor when a long arbor is used. Both
hand and power feed can be employed for the work.
Vertical Milling Machine:
It derives from the vertical position of the spindle. The
machine is available in both types; the Fixed Bed Type as
well as Column and Knee Type.

12. Vertical Milling Machine with Fixed Head
Vertical Milling Machine with Swivelling Head
It carries a Vertical column on a heavy base. The overarm
in this machine is made integral with the column and
carries a housing at its front. This housing is called Head,
can be fixed type or vertical type. In fixed type, the spindle
always remains vertical and can be adjusted up and down.
In swivelling type, the head can be swivelled to any desire
angle to machine the inclined surface.

13. The knee carries an enclosed screw jack, by means of
which it is moved up and down along the parallel Vertical
Guideways provided on the front side of the column. The
saddle is mounted on the knee and can be moved, along
the horizontal guideways provided on the knee, towards and
away from the column. This enables the table to move in
cross direction. The table is mounted on the guideways,
provided on the saddle, which are in the direction normal to
the direction of the guideways on the knee. By means of a
lead screw, provided under the table, the table can be
moved in the longitudinal direction. Thus the work gets up
and down movement by knee, cross movement by saddle
and longitudinal movement by the table. The power feed
can be employed to both saddle and the table. Mostly Face
Milling Cutters and Shell-end type cutters are used on
these machines.

14. Universal Milling Machine:
It is the most versatile of all the milling machines, and after
the lathe it is the most useful machine tool as it capable of
performing most of the machining operations. It differs from
the Plain Milling Machine only in that the table can be given
one more additional movement. Its table can be swivelled on
the saddle in a horizontal plane. For this circular guideways
are provided on the saddle along which it can be swivelled.
A graduated circular base is incorporated under the table
with a datum mark on the saddle, to read directly the angle
through which the table has been swivelled. This special
feature enables the work to be set at an angle with cutter for
milling helical and spiral flutes and grooves. Its overarm can
be pushed back or removed and a vertical milling head can
be fitted in place of the arbor to use it as a vertical milling
machine.

15. Universal Milling MachineUniversal Milling Machine

16. Omniversal Milling Machine:
This is modified version of Plain Milling Machine. It is
provided with two spindles, of which one is horizontal as
in Plain Milling Machine and other is carried out by
Universal Swivelling head. The later can be fixed in
vertical position or can be set at any desire angle up to 90
degree on both the side of vertical, i.e. In a plane parallel
to the front face of the column, and up to 45 degree in a
plane perpendicular to the former direction, i.e. Towards
and away from the column. Another special feature of this
machine is that it carries, in addition to all the possible
adjustments provided in universal machine, two more
adjustment. These adjustments are of the knee, which
can be swivelled at about horizontal axis to tilt the table
and can be moved horizontal also. Hence it will be very
useful in tool room work also.

17. Fixed Bed Type Plain Milling Machine

18. Duplex Head Type Milling Machine

19. Planer Type Milling Machine (Plano Mill)

20. Horizontal Milling Machine

21. Horizontal Milling MachineHorizontal Milling Machine

22. Types of Vertical Milling Machines
Ram-type
Most common
Features of horizontal milling machine
Cutter spindle mounted in vertical
position
Spindle head may be swiveled allowing
machining of angular surfaces

23. Types of Vertical Milling Machines
Ram-type

24. Parts of Ram-Type Mill
Base
Made of cast iron
May contain coolant
reservoir

25. Parts of Ram-Type Mill
Column
Machined face provides
ways for vertical knee
movement
Upper part machined to
produce turret for
overarm mount

26. Parts of Ram-Type Mill
Overarm
Round base
May be adjusted
toward or away from
column and rotated
Locked into position

27. Parts of Ram-Type Mill
Head
Attached to end of
ram
Universal-type
machines allow swivel
in 2 planes

28. Parts of Ram-Type Mill
Motor
Mounted on top of
head
Provides drive to
spindle through V-
belt

29. Parts of Ram-Type Mill
Spindle speed
Speed changed by
variable-speed
pulley/crank or by
belt changes and
reduction gear

30. Parts of Ram-Type Mill
Knee
Moves up and down
on face of column
Supports saddle and
table
Does not contain
gears for automatic
feed

31. Milling Machine Parts
Base
Gives support and rigidity to
machine
Acts as reservoir for cutting fluids
Column face
Precision-machined and scraped
section used to support and guide
knee when moved vertically
Knee
Houses feed mechanism
Attached to column face and
moved vertically

32. Milling Machine Parts
Saddle
On top of knee
Moved in or out by
means of cross feed
hand wheel (manually
or automatically)
Swivel table housing
Fastened to saddle on
universal milling machine
Enables table to be swiveled 45º either side of
centerline

33. Milling Machine Parts
Table
Rests on guideways in saddle
and travels left and right
Supports vise and work
Crossfeed hand wheel
Used to move table in and out
Table hand wheel
Used to move table left and right

34. Milling Machine Parts
Feed dial
Used to regulate table feeds
Spindle
Provides drive for
attachments, arbors, cutters
Overarm
Provides for correct
alignment and support of
arbor and various
attachments
Can be adjusted and locked
in various positions

35. Milling Machine Parts
Arbor support
Fitted to overarm and can be
clamped
Aligns and supports various
attachments
Elevating screw
Gives upward or downward
movement to knee and table
(manually or automatically)
Spindle speed dial
Set by crank used to
regulate spindle speed

38. Milling Machine Attachment
To use the milling machine to its full capacity, various types of
attachments are required. These attachments are generally
classified in to two categories, viz, standard and special
attachments.
Standard attachments have greater adaptability and application
in general type of work. They are capable of dealing with a large
variety of jobs and can be fitted to most of the standard types of
milling machine. These attachments are used for the following
purposes:
1.To hold the cutter: Arbors, Collets, Adaptors, etc.
2.To hold the work piece on the table, in desire position, and
impart additional movements, if required; such as vices, Circular
table, indexing head, tail stock etc.
3.To act as Auxiliary Spindles; in conjunction with the main
spindle, in order to avoid the necessity of various special types of
machine; such as vertical milling attachment, spiral milling
attachment, slotting attachment, etc.

39. Special attachment:
These are the attachment which are specially designed and
used on a standard milling machine to make it suitable for
performing special milling operations in mass production of
identical items. These attachment mainly include the
various milling fixtures.
Standard attachments: Arbors, Adaptors and
Collets
They are all used for holding the milling cutters during the
operations. This is the common method of mounting the
cutters, although they are mounted on the machine spindle
directly also.

40. Arbors
Arbors
Used for mounting milling cutter
Inserted and held in main spindle by draw bolt
Shell-end mill arbors
Permit face milling horizontally or vertically
Fit into main spindle

41. The Arbor Assembly
Milling cutter driven by key that fits into
keyways on arbor and cutter
 Prevents cutter from turning on arbor
Spacer and bearing bushing hole cutter in
position

42. 66-42
Draw-in bar holds arbor firmly
in place in the spindle
Tapered end of arbor held securely in
machine spindle by draw-in bar
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Outer end of arbor assembly supported
by bearing bushing and arbor support

43. 66-43
Milling Arbor
Used to hold cutter during machine
operation
Must follow proper procedure of
mounting or removing arbor to preserve
accuracy of machine
 May damage taper surfaces of arbor or
machine spindle
 Cause arbor to bend
 Make cutter run out of true

44. Arbor AssyArbor Assy

45. Collets and Adapters
Collet adapters
used for mounting drills or other tapered-shank tools
in main spindle of machine or vertical milling
attachment
Quick-change adapter
Mounted in spindle
Permits such operations as drilling, boring, and
milling without change in setup of workpiece

46. Taper in Milling Machine SpindleTaper in Milling Machine Spindle

47. Different TypesDifferent Types
OfOf
ArborArbor
ColletsCollets

48. Arbors, Collets, and Adapters

49. Milling Machine Attachments
Designed to hold special attachment that
increase versatility of machine
Vertical, high-speed, universal, rack milling, slotting
Designed to hold standard cutters,
Arbors, collets, and adapters
Designed to hold workpiece,
Vise, rotary table, indexing (dividing) head

50. Vertical Milling Attachment
Enables plain or universal milling machine to be
used as a vertical milling machine
Mounted on face of column or overarm
Angular surfaces made by swiveling head,
parallel to face of column up to 45º either side
of vertical
Used for face milling, end milling, drilling, boring
and T-slot milling
Universal milling attachment modification allows
swiveling in two planes for cutting compound
angles

51. Vertical Milling Attachment

52. Slotting Attachment
Converts rotary motion of spindle into reciprocating
motion
Cutting keyways, splines, templates, and irregularly
shaped surfaces
Length of stroke controlled by adjustable crank
Tool slide may be swiveled to any angle in plane parallel
to face of column

53. Slotting Attachment

54. Plain vise
Jaws parallel or 90º to axis of spindle
Milling Machine Vises

55. Swivel base vise
Can swivel through 360º in horizontal plane
Milling Machine Vises

56. Milling Machine Vises
Universal vise
Can swivel through 360º in horizontal plane and
tilted from 0º to 90 in vertical plane

57. Fixturing
Systems
Easy-to-adjust Stop

58. Milling Cutters

59. Milling cutters are classified into different categories
depending on different criteria as described below :
According to the Construction of Milling Cutter
(a) Solid milling cutter
(b) Inserted teeth cutter
(c) Tipped solid cutter
Solid cutter consists of teeth integral with the cutter body,
in tipped cutter, teeth are made of cemented carbide or
satellite, teeth are brazed to steel cutter body called shank.
Inserted teeth cutter are larger in diameter, teeth of hard
material are inserted and secured in the shank.

60. According to Relief Characteristics of the Cutter
Teeth
(a) Profile relieved cutter
(b) Form relieved cutter
In case of profile relieved cutter, a relief to cutting edges is
provided by grinding a narrow land at their back. In case of
form relieved cutters a curved relief is provided at the back
of the cutting edges.
According to Method of Mounting the Cutters
(a) Arbor type
(b) Facing cutter
(c) Shank cutter

61. Arbor type cutters have a central hole and keyways for their
mounting on arbor. Shank type cutters are provided with
straight or tapered shanks inserted into the spindle nose
and clamped there. Facing type milling cutter are used to
produce flat surfaces. These are balled or attached to the
spindle nose or the face of a short arbor (stub arbor).
According to Direction of Rotation of the Cutter
(a) Right hand rotational cutter
(b) Left hand rotational cutter
A right hand rotational cutter rotates in an anticlockwise
direction when viewed from end of the spindle while left
hand rotational cutter rotates in a clockwise direction.

62. According to the Direction of Helix of the Cutter
Teeth
(a) Parallel straight teeth
(b) Right hand helical
(c) Left hand helical
(d) Alternate helical teeth
Parallel or straight teeth cutter consists of teeth parallel to
axis of rotation of the cutter with zero helix angle. In case of
right hand and left hand helical teeth cutters, teeth cut at an
angle to the axis of rotation of the cutter. Teeth have
opposite inclination in both the cutters. Alternate helical
teeth cutter has alternate teeth of right hand and left hand
helical teeth cutters.

63. According to Purpose of Use of the Cutter
(a) Standard milling cutter
(b) Special milling cutter
Special milling cutters are designed to perform special
operations which may be combination of several
conventional operations. Standard milling cutters are the
conventional cutters which are classified as given below.
Plain Milling Cutters
These cutters are cylindrical in shape having teeth on their
circumference. These are used to produce flat surfaces
parallel to axis of rotation. Plain milling cutter is shown in
Figure 1.5. Depending upon the size and applications plain
milling cutters are categorized as light duty, heavy duty
and helical plain milling cutters.

64. Plain Milling Cutter & its element

65. 65
Milling Cutter Materials
Cutter Characteristics
 Harder than metal being machined
 Strong enough to withstand cutting
pressures
 Tough to resist shock resulting from
contact
 Resist heat and abrasion of cutting
 Available in various sizes and shapes

66. Plain Milling Cutters
Once widely used
Cylinder of high-speed steel
with teeth cut on periphery
Used to produce flat surface
Several types
Light-duty
Light-duty helical
Heavy-duty
High-helix

67. Light-Duty Plain Milling
Cutter
Less than ¾ in. wide, straight teeth
Used for light milling operations
Those over ¾ in have helix angle of 25º
Too many teeth to permit chip clearance
67

68. Heavy-Duty Plain Milling Cutters
Have fewer teeth than light-duty type
Provide for better chip clearance
Helix angle varies up to 45º
Produces smoother surface because of shearing
action and reduced chatter
Less power required

69. High-Helix Plain Milling Cutters
Have helix angles from 45º to over 60º
Suited to milling of wide and intermittent surfaces on
contour and profile milling
Sometimes shank-mounted with pilot on end and
used for milling elongated slots

70. Standard Shank-Type Helical Milling
Cutters
Called arbor-type cutters
Used for
Milling forms from solid metal
Removing inner sections from solids
Inserted through previously drilled hole and supported
at outer end with type A arbor support

71. Side Milling Cutters
Comparatively narrow cylindrical milling cutters
with teeth on each side and on periphery
Used for cutting slots and for face and straddle
milling
operations
Free cutting action at high speeds and feeds
Suited for milling deep, narrow slots

72. Face Milling Cutters
Generally over 6 in. in diameter
Have inserted teeth made of high-
speed steel held in place by
wedging device
Most cutting action occurs at beveled
corners and periphery of cutter
Makes roughing and finishing cuts in
one pass

73. Shell End Mills
Face milling cutters under 6 inch
Solid, multiple-tooth cutters with
teeth on face and periphery
Held on stub arbor
May be threaded or use key in
shank to drive cutter

74. Angular Cutters
Teeth neither parallel nor perpendicular to cutting axis
Used for milling angular surfaces
Grooves, serrations, chamfers and reamer teeth
Divided into two groups
Single-angle milling cutters
Double-angle milling cutters

75. Angular Cutters
Single-angle
Teeth on angular surface
May or may not have teeth
on flat
45º or 60º
Double-angle
Two intersecting angular
surfaces
with cutting teeth on both
Equal angles on both side of
line
at right angle to axis

76. Formed Cutters
Incorporate exact shape of part to be produced
Useful for production of small parts
Each tooth identical in shape
Sharpened by grinding tooth face (may have positive,
zero or negative rake)
Important to maintain original rake
Difficult to sharpen

77. Types of Formed Cutters
Concave Convex Gear Tooth

78. Metal-Slitting Saws
Basically thin plain milling cutters with
sides relieved or "dished" to prevent
rubbing or binding when used
Widths from 1/32 to 3/16 in.
Operated at approximately 1/4 to 1/8 of
feed per tooth used for other cutters

79. Metal-Slitting Saws

80. End Mills
Cutting teeth on end as well as periphery
Fitted to spindle by suitable adapter
Two types
Solid end mill: shank and cutter integral
Smaller with either straight or helical
flutes
Two flute or four flute
Shell end mill: separate shank

81. T-Slot Cutter
Used to cut wide horizontal groove at bottom of T-slot
After narrow vertical groove machined with end mill or
side milling cutter
Consists of small side milling cutter with teeth on both
sides and integral shank for mounting

82. Dovetail Cutter
Similar to single-angle milling cutter with integral shank
Used to form sides of dovetail after tongue or groove
machined
Obtained with 45º, 50º, 55º, or 60º angles

83. Fly cutters
Single-pointed cutting tool with
cutting end ground to desired
shape
Mounted in special adapter or
arbor
Fine feed must be used
Used in experimental work
instead of a specially shaped
cutter

86. End Mill CutterEnd Mill Cutter

87. Fly CutterFly Cutter

88. Milling Operations
Horizontal
milling
Vertical
milling

89. Following different operations can be performed on a
milling machine :
(a) Plain milling operation
(b) Face milling operation
(c) Side milling operation
(d) Straddle milling operation
(e) Angular milling operation
(f) Gang milling operation
(g) Form milling operation
(h) Profile milling operation
(i) End milling operation
(j) Saw milling operation
(k) Slot milling operation
(l) Gear cutting operation
(m) Helical milling operation
(n) Cam milling operation
(o) Thread milling operation

90. Plain Milling or Slab Operation
This is also called slab milling. This operation produces flat
surfaces on the workpiece. Feed and depth of cut are
selected, rotating milling cutter is moved from one end of
the workpiece to other end to complete the one pairs of
plain milling operation.

91. Face Milling Operation
This operation produces flat surface at the face of the
workpiece. This surface is perpendicular to the surface
prepared in plain milling operation. This operation is
performed by face milling cutter mounted on stub arbor of
milling machine. Depth of cut is set according to the need
and cross feed is given to the work table.

92. Side Milling Operation
This operation produces flat and vertical surfaces at the
sides of the workpiece. In this operation depth of cut is
adjusted by adjusting vertical feed screw of the workpiece.
Gang Milling
In this milling it involves the use of a combination of more
than two cutters mounted on a common arbor (i.e. gang of
cutters)

93. Angular Milling Operation
Angular milling operation is used to produce angular
surface on the workpiece. The produced surface makes an
angle with the axis of spindle which is not right angle.
Production of „V‟ shaped groove is the example of angular
milling opration.

94. Straddle Milling Operation
This is similar to the side milling operation. Two side milling
cutters are mounted on the same arbor. Distance between
them is so adjusted that both sides of the workpiece can be
milled simultaneously. Hexagonal bolt can be produced by
this operation by rotating the workpiece only two times as
this operation produces two parallel faces of bolt
simultaneously.

95. Form Milling Operation
Form milling operation is illustrated in Figure. This
operation produces irregular contours on the work surface.
These irregular contours may be convex, concave, or of
any other shape. This operation is done comparatively at
very low cutter speed than plain milling operation.
Form Milling operation

96. Profile Milling Operation
In this operation a template of complex shape or master
die is used. A tracer and milling cutter are synchronized
together with respect to their movements. Tracer reads
the template or master die and milling cutter generates the
same shape on the workpiece. Profile milling is an
operation used to generate shape of a template or die.
This operation is demonstrated in Figure
Profile Milling Operation

97. End Milling Operation
End milling operation produces flat vertical surfaces, flat
horizontal surfaces and other flat surfaces making an
angle from table surface using milling cutter named as end
mill. This operation is preferably carried out on vertical
milling machine. This operation is illustrated in Figure
End Milling Operation

98. Saw Milling Operation
Saw milling operation produces narrow slots or grooves
into the workpiece using saw milling cutter. This operation
is also used to cut the workpiece into two equal or unequal
pieces which cut is also known as “parting off”. In case of
parting off operation cutter and workpiece are set in a
manner so that the cutter is directly placed over one of the
„T‟ slot of the worktable as illustrated in Figure

99. Slot Milling Operation
The operation of producing keyways, grooves, slots of
varying shapes and sizes is called slot milling operation.
Slot milling operation can use any type of milling cutter like
plain milling cutter, metal slitting saw or side milling cutter.
Selection of a cutter depends upon type and size of slot or
groove to be produced. Right placement of milling cutter is
very important in this operation as axis of cutter should be
at the middle of geometry of slot or groove to be produced.
The operation is illustrated in Figure

100. Milling Operations
(a) Schematic illustration of conventional milling and climb
milling.
(b) Slab-milling operation, showing depth of cut, d; feed per
tooth, f; chip depth of cut, tc; and work piece speed, v.
(c) Schematic illustration of cutter travel distance to reach
full depth of cut.

101. The Milling Processes
Peripheral milling
Up milling (Conventional milling)
Down milling (Climb milling)
Face milling
End milling

102. Cutting Speeds in Milling
Approximate range of recommended
cutting speeds for milling operations.
CUTTING SPEEDWORKPIECE MATERIAL
m/min ft/min
Aluminum alloys
vast iron, gray
Copper alloys
High-temperature alloys
Steels
Stainless steels
Thermoplastics and thermosets
Titanium alloys
300-3000
90-1300
90-1000
30-550
60-450
90-500
90-1400
40-150
1000-10,000
300-4200
300-3300
100-1800
200-1500
300-1600
300-4500
130-500
Note: (a) These speeds are for carbides, ceramic, cermets, and diamond cutting tools. Speeds for
high-speed steel tools are lower than indicated.
(b) Depths of cut, d, are generally in the range of 1 mm-8 mm (0.04 in.-0.3 in).
(c) Feeds per tooth, f, are generally in the range of 0.08 mm/rev-0.46 mm/rev (0.003 in./rev -
0.018 in./rev).

103. Milling Alignment TestMilling Alignment Test