It is good explained

1. Heritage Institute of Technology
Department of Mechanical Engineering
Workshop/Manufacturing Practices
MECH 1051
Machine Shop: Milling Machine

2. Milling Machine
 A milling machine is a machine tool which is used to make
surface by removing metal as the work piece is fed against
rotating multipoint cutting tool.
 The cutting motion is provided on the milling cutter which is a
rotation.
 The feed motion is provided to the job which is a linear motion.
 Milling is used to make surface having good surface finish,
slot, keyways and also generate gear tooth profile.
 The first successful milling cutter was developed by Eli
Whitney in the year 1818.

3. Machining in milling

4. Description of Milling Machine
cutter

5. Basic Components of Milling Machine
• Base: The base is the rigid cast iron structure attached on the
shop floor which takes the entire load of the column.
• Column: the column is the main supported frame mounted
vertically to the base. It is box shaped and consisted with all the
driving mechanisms.
• Overhanging arm: It is situated at the top of the column and It
extends beyond the column face provides the bearing support in
one end of the arbor.
• Spindle: It is located at the upper part of the column and
receives power from the motor through belt pulley drive and
transmit it to the arbor.

6. Continued..
• Arbor: An arbor may be considered as an extension of the
machine spindle on which milling cutter is situated. The arbor
may be supported at the furthest end of the overhanging arm. It
is made with taper shanks for proper alignment of the machine
spindle.
• Knee: It is the rigid grey cast iron supporting which carries
saddle and table and moves up and down along the guide ways
of column.
• Saddle: Saddle is placed at the top of the knee which can slides
exactly at right angle to the column face.
• Table: The table rests on the ways of saddle which carries the
vice or holding device to hold the work piece.

7. Specification of Milling Machine
 The size of the milling machine is designed by the
dimensions of the working surface of the table and its
maximum length of longitudinal, cross and vertical travel
of the table.
 In addition to that following are also required to specify-
1. number of spindle speed
2. number of automated feeds
3. spindle nose taper
4. power required floor space
5. number of axis of revolution

8. TYPES OF MILLING MACHINE
The usual classification according to the general design of the milling machine.
(1) Column and Knee type:
(a) Hand milling machine
(b) Plain milling machine
(c) Universal milling machine
(d) Omniversal milling machine
(e) Vertical milling machine
(2) Manufacturing or Fixed Bed type:
(a) Simplex milling machine
(b) Duplex milling machine
(c) Triplex milling machine
(3) Planner type:
(4) Special type:
(a) Rotary table milling machine
(b) Drum milling machine
(c) Planetary milling machine
(d) Pantograph, profiling and tracer controlled milling machine

9. UP MILLING
In up-milling, the feed direction of the work-piece is opposite to
its rotation of cutter.
 The chip thickness starts at zero and increases toward the end of the
cut.
 This process is called Conventional milling process.
 Forces, mainly radically upward, will tend to lift the work piece from
the table. The surface finish is poor in this process.
 Thick chips at the exit from the cut will reduce tool life.

10. DOWN MILLING
In down-milling, the feed direction of the work-piece is opposite
to its rotation of cutter.
 The thickness of the chip is maximum when the tooth begins its cut
and reduces to minimum when the cut terminates.
 The direction of the cutting force is radial downward. So the fixture
design is easier
 The particular milling is called climb milling.
 The tool life is more and the surface finish is good.

11. VERTICAL MILLING
In the vertical machine, the cutting tool and spindle move up and
down
A vertical milling machine's spindle
axis is aligned in a vertical manner to
the machine's bed. That means that the
cutting tool is arranged vertically to
shape the metal or other material into
the desired form.
The vertical mill moves while the
part remains stationary.
The vertical milling machine is used
to produce slots, key ways etc.

12. HORIZONTAL MILLING
Horizontal milling machines have a spindle or cutters mounted on a
horizontal arbor above an X-Y table
The cutter used here are circular
type having teeth at the periphery of
the cutter.
The horizontal milling machine is
used to mill the surface, cut the slot,
chase the thread generate the gear
etc.
This is the most common type
milling machine. The speed of the
cutter is slightly more than the
vertical milling machine

13. Milling operations
 In milling machine following operations can be done-
 Making of horizontal, vertical and angular flat surface
 Making of keyways, slots, grooves etc.
 Making of external and internal thread
 Most importantly generation of gear tooth.

14. Milling operations
To see the video click here
 https://www.youtube.com/watch?v=2jc3HkrHh9s
 https://www.youtube.com/watch?v=AxHexqN0Hr0

15. Thank you