Milling is a machining process that uses rotary cutters to remove material from a workpiece by feeding the cutter into the workpiece. There are three main types of milling machines: horizontal, vertical, and universal. Horizontal milling machines have a horizontally mounted spindle, vertical milling machines have a vertically oriented spindle, and universal milling machines allow the table to swivel to permit angular milling operations. Milling machines consist of a base, column, knee, saddle, table, spindle, and other components to precisely cut metal and other solid materials.

1. MILLING

2. MILLING
• Milling is the machining process of using rotary
cutters.
• works remain stationary.
• Cutting action takes place by feeding the cutter
against the work piece.

3. • Rotation speed of the cutter depends on
1. Cutting speed recommended for material
2. Diameter of the cutter

4. • Milling produces flat (horizontal, vertical, angular) and
profile surfaces.
• Milling operation produces better accuracy and surface
finish.
Classification of milling machines
Milling machine are classified in to three types
• 1. Horizontal milling machine
• 2. Vertical milling machine
• 3. Universal milling machine

5. •A milling machine having a
horizontal spindle is called
horizontal milling machine.
•The horizontal arbor is
mounted in between the spindle
and the supporting brackets.
•Milling cutters are mounted on
the arbor.
•The table can be fed in three
directions namely longitudinal
(X) crosswise (Y) and vertical
(Z)
Horizontal milling machine

6. The feed is longitudinal when the table is
moved at right angles to the spindle axis.
The feed is vertical when the table is moved in
the upward/downward directions.
The feed is crosswise when the table is moved
parallel to the spindle axis.

7. vertical milling machine
• In a vertical milling machine the spindle is
vertical or perpendicular to the table.
• The spindle rotates about the vertical
axis. The spindle can be moved up and
down and the vertical head also can be
tilted / swivelled.
• The vertical milling machine is suitable
for boring and -for pocket milling, profile
milling

8. vertical milling machine

9. UNIVERSAL MILLING MACHINE
• The universal milling machine is similar in
construction to the horizontal machine.
• But its table, apart from having movements in 3
directions, can also be swiveled about the
horizontal axis.
• The maximum swiveling is 45° both in clockwise
and anticlockwise directions.
• This swiveling of the table permits angular feed.
Helical gears, Helical grooves,etc.
• Can be milled using dividing head and chuck.

11. Specification of a milling machine
• The milling machine is specified by the
• 1. Dimension of the working surface of the table
• 2. Longitudinal travel of the table
• 3. Cross travel of the table
• 4. Vertical travel of the table
• 5. Number of spindle speed
• 6. Spindle nose taper

12. PARTS OF A MILLING MACHINE

13. Base
• The base of the machine is
made of grey cast iron. It is
accurately machined on its
top and bottom surface and
serves a foundation member
for all the other parts which
rest upon it. It carries the
column at its one end. In
some machines the base is
hollow and serves as a
reservoir for cutting fluids

14. Column
• The column is the main
supporting frame mounted
vertically on the base. The
column houses all the driving
mechanism for the spindle and
table feed. The main motor is
mounted in the column. The top
of the column is finished to hold
an over arm in horizontal and
vertical head in vertical milling
machine. Column houses the
gears for varying the rpm of the
spindle.

15. KNEE
• The knee is of rigid casting
that slides up and down
along a precision-machined
guide way on the column.
The knee houses the feed
mechanism of the table and
the different controls to
operate it. The feed motor
and gearbox are usually
incorporated in the knee.

16. Gearbox
• The gearbox of the
spindle drive
comprises shafts
with bearings and
gears, and controls
for the setting of the
spindle speed.

17. Spindle
• The spindle is housed in the
upper part of the column. It
receives power from the motor
and transmits it to the arbor.
The speed of the spindle can
be selected by the speed
gearbox. The feeds can
selected through the feed
gearbox. The spindle is
arranged horizontally in the
horizontal milling machine
and vertically in the vertical
milling machine.

18. Saddle
• The saddle is placed on the
top of the knee which slides
on the guide way, set exactly
at 90° to the column face. A
cross-feed screw near the top
of the knee engages a nut on
the bottom of the saddle to
move it horizontally for
applying the cross-feed.

19. Table
• The table rests on the guide way on
the saddle and travels longitudinally.
T slots are provided on the table to
mount the work pieces directly or to
mount the work-holding devices.
The longitudinal feed-stops are
located on the front of the table. This
disengage the machine feed at a set
position. The table is also fitted with
a hand wheel for handfed in the
longitudinal direction, and a lever
for locking the table. There is a
channel around the edges of the
table to collect the cutting fluid.

20. Over arm
• In horizontal milling
machine the over arm
is mounted on the top
of the column above
the spindle, and it acts
as a support with long
arbor. The arm is
adjustable so that the
bearing support may
be provided nearest to
the cutter.

21. Electrical equipment’s
• The electrical equipment
for the different controls
of the machine is usually
grouped in the column.
The equipment consists
mainly of fuses, motor
breakers and contactors.
Motor breakers switch off
the power in the event of
an overload.

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