Milling & Grinding Machines

1. Milling & grinding machines
SHARANABASAPPA V Bhurke
ASST. PROFESSOR
Dept. of mechanical Engg.
DBIT-BENGALURU

2. CONTENTS
Milling
Milling Machines
Milling Operations
Specifications of Milling Machine
Grinding
Abrasives & Bonding Materials
Grinding Machines

3. MILLING
Milling: is a metal cutting operation in
which the excess material from the work
piece is removed by rotating multipoint
cutting tool called milling cutter.
Milling machine: is a power operated
machine tool in which work piece mounted
on a moving table is machined to various
shapes when moved under a slow revolving
serrated cutter.

4. PRINCIPLE OF MILLING

5. COMPARISON BETWEEN UP MILLING & DOWN MILLING
SL.
NO.
UP MILLING
(CONVENTIONAL MILLING)
DOWN MILLING
(CLIMB MILLING)
01 Work piece fed in the
opposite direction that of the
cutter.
Work piece fed in the same
direction that of the cutter.
02 Chips are progressively
thicker.
Chips are progressively thinner.
03 Strong clamping is required
since the cutting force is
directed upwards & tends to
lift the work piece.
Strong clamping is not required
since the cutting force is directed
downwards & keep the work piece
pressed to the table.
04 Gives poor surface finish,
since chips gets accumulated
at the cutting zone.
Gives good surface finish, since
the chips are thrown away during
cutting.
05 Used for hard materials. Used for soft materials and
finishing operations.

6. CLASSIFICATION OF MILLING
MACHINES
1. Column and knee milling machines
a. Plain column & knee type milling machine
- Horizontal spindle type
- Vertical spindle type
2. Bed type milling machine
3. Planer type milling machine
4. Special purpose milling machine
a. Tracer controlled milling machine
b. Thread milling machine
c. CNC milling machine

7. HORIZONTAL MILLING MACHINE
FIG. HORIZONTAL MILLING MACHINE
MAJOR PARTS :
1. BASE
2. COLUMN
3. SPINDLE
4. OVERARM
5. KNEE
6. SADDLE
7. WORKTABLE

9. VERTICAL MILLING MACHINE
MAJOR PARTS :
1. BASE
2. COLUMN
3. SPINDLE
4. SPINDLE HEAD
5. KNEE
6. SADDLE
7. WORKTABLE
FIG. VERTICAL MILLING MACHINE

11. DIFFERENCES BETWEEN HORIZONTAL &
VERTICAL MILLING MACHINES
SL. NO. HORIZONTAL MILLING MACHINE VERTICAL MILLING MACHINE
01
Spindle is horizontal &
parallel to the worktable.
Spindle is vertical &
perpendicular to the worktable.
02
Cutter cannot be moved up
& down.
Cutter can be moved up &
down.
03
Cutter is mounted on the
arbor.
Cutter is directly mounted on
the spindle.
04 Spindle cannot be tilted.
Spindle can be tilted for
angular cutting.
05
Operations such as plain
milling, gear cutting, form
milling, straddle milling,
gang milling etc., can be
performed.
Operations such as slot
milling, T-slot milling, angular
milling, flat milling etc., can be
performed and also drilling,
boring and reaming can be
carried out.

12. MILLING OPERATIONS
Plain or slab milling
Face milling
End milling
Slot milling
Angular milling
Form milling
Straddle milling
Gang milling
Slitting or saw milling
Gear cutting

13. PLAIN/SURFACE/ SLAB MILLING
FIG. PLAIN MILLING
Plain Milling:
Process to get the flat
surface on the work
piece in which the cutter
axis and work piece axis
are parallel.
Cutter: Plain/ Slab
milling cutter.
Machine: Horizontal
Milling m/c.

14. FACE MILLING
FIG. FACE MILLING
Face Milling:
Operation carried out for
producing a flat surface, which
is perpendicular to the axis of
rotating cutter.
Cutter: Face milling cutter.
Machine: Vertical Milling
Machine

15. END MILLING
FIG. END MILLING
End Milling:
Operation performed for
producing flat surfaces, slots,
grooves or finishing the edges of
the work piece.
Cutter: End milling cutter.
Machine: Vertical Milling
Machine

16. SLOT MILLING
FIG. T-SLOT MILLING
FIG. DOVE TAIL SLOT MILLING
SLOT Milling:
Operation of producing slots
like T-slots, plain slots, dovetail
slots etc.,
Cutter: End milling cutter, T-
slot cutter, dovetail cutter or
side milling cutter
Machine: Vertical Milling
Machine

17. ANGULAR MILLING
FIG. ANGULAR MILLING
Angular Milling:
Operation of producing all types
of angular cuts like V-notches
and grooves, serrations and
angular surfaces.
Cutter: Double angle cutter.
Machine: Horizontal Milling
Machine

18. FORM MILLING
FIG. FORM MILLING
End Milling:
Operation of producing all types
of angular cuts like V-notches
and grooves, serrations and
angular surfaces.
Cutter: Double angle cutter.
Machine: Horizontal Milling
Machine

19. STRADDLE MILLING
FIG. STRADDLE MILLING
Straddle Milling:
Operation of machining two
parallel surfaces
simultaneously on a work piece.
Cutter: 2 or more side & face
milling cutters
Machine: Horizontal Milling
Machine

20. GANG MILLING
FIG. GANG MILLING
Gang Milling:
Process to get different profiles
on the work piece
simultaneously with two or
more cutters at one stretch.
Cutter: Different cutters as
required.
Machine: Horizontal Milling
Machine

22. SPECIFICATIONS OF MILLING MACHINE
1. Size of the work table: expressed in length x
width Eg: 1500 x 30mm.
2. Longitudinal movement: Total movement of
table in mm(X-direction). Eg:800mm
3. Transverse movement: Total movement of
saddle along with table in mm(Y-direction).
Eg:200mm
4. Vertical movement: Total movement of table,
saddle & knee in mm mm(Z-direction).
Eg:380mm
5. Range of the speed: Speed variation in the
gear box in RPM. Eg: 45 to 200 rpm.
6. Power capacity of the motor in HP. Eg: 2 HP

23. GRINDING(Abrasive machining)
• Grinding is a surface finishing operation
where very thin layer of material is removed
in the form of fine dust particles. (thickness
0.25-0.5mm)
• Grinding can be defined as a material
removal process by the abrasive action
between rotating abrasive wheel & the work
piece.
• Grinding machine is a power operated
machine tool where, the work piece is fed
against a constantly rotating abrasive wheel
which is also called as Grinding wheel so
that a thin layer of material is removed from
the work piece.

24. PRINCIPLE OF GRINDING
The work piece is fed
against a constantly
rotating abrasive
wheel so that a thin
layer of material is
removed from the it.
FIG. GRINDING

25. GRINDING WHEEL
Abrasives
Bonding
materials
Grinding
wheels

26. ABRASIVES
• Abrasives: These are the mineral materials
employed for sharpening, grinding &
polishing operations.
• Abrasives are classified as natural &
artificial.
• Natural Abrasives: Emery, Corundum,
Diamond etc,.
• Artificial Abrasives: Silicon Carbide(SiC),
Aluminum Oxide(Al2O3), Cubic Boron
Nitride(CBN) etc,.

27. Bonding materials & Process
• Vitrified Process: Abrasive+ Fed spar & clay,
heated at higher temperatures in kilns.75-80%
of grinding wheels are made by this process.
• Silicate Process: Abrasive+ Silicate of soda.
Baked @ 260°C for 20 to 80 Hrs.
• Elastic Process: Abrasives + Shellac. Baked
@150°C for few hours.
• Vulcanite or Rubber Process: Abrasive+ Pure
rubber+ Sulphur.

28. FIG. COATED &MOUNTED ABRASIVE WHEELS

29. CLASSIFICATION OF GRINDING
MACHINES
Grinding machines are classified based on their
construction & type of surface produced.
1. Bench Grinding Machine
2. Surface Grinding Machine
3. Cylindrical Grinding Machine
4. Centerless Grinding Machine
5. Internal Grinding Machine
6. Special Purpose Grinding Machine

30. SURFACE GRINDING MACHINE
FIG. PRINCIPLE OF SURFACE GRINDING
Principle: The work
piece is fed against a
constantly rotating
abrasive wheel so that a
thin layer of material is
removed from the it.
Work Piece Type: Flat,
Angular & Irregular
surfaces

31. FIG. SURFACE GRINDING MACHINE

32. CYLINDRICAL GRINDING MACHINE
FIG. PRINCIPLE OF CYLINDRICAL
GRINDING
Principle:
The work piece is held
between two centers & and
the rotating grinding wheel
is fed against it.
External Grinding machine
Work Piece Type:
Cylindrical surfaces may be
straight, curved or
contoured.

33. FIG. CYLINDRICAL GRINDING MACHINE

34. CENTERLESS GRINDING MACHINE
FIG. PRINCIPLE OF
CENTERLESS GRINDING
Principle: The work piece is placed
on work rest blade between two
wheels namely grinding &
regulating wheel, which are rotating
in clockwise & work piece rotates
counter clockwise. Grinding wheel
remove material from W/P surface &
regulating wheel regulates the W/P.
Centerless: Means work piece is not
held between centers.
Work Piece Type: Curved or
Cylindrical surfaces of long slender
rods which cannot be ground on
cylindrical grinding.

35. FIG. CENTERLESS GRINDING MACHINE

36. ASSIGNMENT
1. With sketch explain the principle of milling & grinding.
2. Distinguish between up milling and down milling.
3. With neat sketch explain the column and knee milling
machine. Draw a neat sketch of vertical milling
machine and explain its parts.
4. Distinguish between horizontal milling m/c and
vertical milling m/c.
5. List the different operations performed on milling
machine and briefly explain the operations.
6. What are abrasives? Give some examples of natural
and artificial abrasives.
7. Sketch and explain centerless grinding with principle.
8. Write a note on bonding materials & processes.
9. Give the specifications of milling machine.
10. Sketch and explain the following operations
11. (i) Surface grinding (ii) Cylindrical grinding.

37. REFERENCES
• www.google.com
• www.youtube.com
• A Text Book of Mechanical Engineering
- K R Gopalkrishna
• Elements of Mechanical Engineering
-M Sreenivasa Reddy
• Elements of Mechanical Engineering
- Kestoor Pravin

38. Any Questions…??????????????

39. Thank You….!!!!!!!!!!!