1. Module 5 Milling Machines Dr. Salah Gasim Ahmed MET 103

2. Dr. Salah Gasim Ahmed MET 103
What is milling
Milling is the process of machining
flat,
curved,
or irregular surfaces
by feeding the workpiece against a rotating cutter containing a number of cutting edges.
A milling machine uses on or more revolving cutters to shape a work piece.
Dr. Salah Gasim Ahmed MET 103

3. Types of milling machines:
Vertical milling machines
Turret (head can be tilted or swiveled)
Fixed head (head can not be tilted or swiveled)
Horizontal milling machines
Plain horizontal milling machines (table is fixed at right angle to the knee)
Universal milling machines (the table can be pivoted in a horizontal plane)
Milling machines for special purposes
Dr. Salah Gasim Ahmed MET 103

4. Vertical Milling machine
Milling head
Ram
Spindle
Table
Saddle
Knee
Column
Base

5. Ram
Milling head
Spindle
Table
Saddle
Column
Knee
Base

6. Horizontal milling machine
Spindle
Ram
Arbor Support
Column
Table
Saddle
Knee
Base
Dr. Salah Gasim Ahmed MET 103

7. Spindle
Arbor support
Ram
(or over arm)
Table
Column
Saddle
Knee
Base

8. Universal Milling machine
Vertical milling attachment

9. Milling machine attachment and accessories
There are three classes of accessories:
Those which increase the versatility of the milling machine e.g.:
Vertical milling attachment
Slotting attachment
Those which holds the cutter
Those which holds the work piece
Dr. Salah Gasim Ahmed MET 103

10. Dr. Salah Gasim Ahmed MET 103
Cutter holding devices:
Arbor
Used for mounting the cutter
It is held in the main spindle by a draw bolt
The outer end is supported by the arbor support
The cutter is positioned on the arbor by collars
Collet adaptor
It is held in the spindle the same manner as the arbor
It is used for mounting tools with taper shank
Quick change adaptor
Used for holding wide range of cutting tools
Dr. Salah Gasim Ahmed MET 103

11. Arbor installation

12. Spring collet

13. Quick-change adaptor and tool holder
chuck
Collet chuck

14. Work holding devices: The most common types are: Vises V-blocks
Mainly used for round works
Angle plates
They are used for large works or special shapes
Fixtures
They are made to hold a particular work piece
Indexing head (dividing head)
It permits the cutting of gears, ratchets, bolt heads
Clamps

15. Vises Plain vise Swivel base vise Universal vise
Jaws parallel or at right angle to the spindle axis
Swivel base vise
it can swivel in a horizontal plane
Universal vise
it can swivel in a horizontal plane,3600, and can be tilted 0 – 900 in a vertical plane

16. Clamps
When work can not be held in a vise or a fixture it is clamped on the table. Here are some types of clamps:
Straight clamp
Finger clamp
Double finger clamp
Screw clamp
U-clamp
Goose neck clamp
Universal clamp

17. Indexing head

18. Milling cutters Plain milling cutter Plain slitting cutter
There many types of milling cutter. Here are some examples:
Plain milling cutter
Plain slitting cutter
Shell milling cutter
Side milling cutter
End milling cutter
Gear milling cutter
T-slotting cutter
Dove-tail slotting cutter

19. Cutting speeds, feeds and depth of cut:
Factors for determining speed (rpm)
Type of work material
Cutter material
Diameter of cutter
Surface finish
Depth of cut
Rigidity of machine and work setup

20. High speed steel cutter
The spindle speed
(inch)
(metric)
The Value of CS is taken from table(1)
Table (1) Milling Machine Cutting Speeds
Material
High speed steel cutter
Carbide cutter
ft/min
m/min
Machine steel 80 25
200 60
Tool steel 65 19
160 50
Cast iron 70 20
Bronze 90 30
300
Aluminium
750
225
1500

21. (High-Speed Steel Cutters)
Milling feed
Feed = N x cpt x rpm
Where,
N: Number of teeth in milling cutter
cpt: chip per teeth for particular cutter, see table (2).
rpm revolution per minute of the cutter
Table (2) Recommended Feed Per Tooth
(High-Speed Steel Cutters)
Material
Side mill
End mills
Plain helical mills
Inches
Millimeter
Inch
Machine steel
.007
0.18
.006
0.15
.010
0.25
Tool steel
.005
0.13
.004
0.10
Cast iron
Bronze
.008
0.20
.009
0.23
.011
0.28
Aluminium
.013
0.33
.018
0.46

22. Table (1) Milling Machine Cutting Speeds Material
High speed steel cutter
Carbide cutter
ft/min
m/min
Machine steel 80 25
200 60
Tool steel 65 19
160 50
Cast iron 70 20
Bronze 90 30
300
Aluminium
750
225
1500
Table (2) Recommended Feed Per Tooth (HSS Cutters)
Material
Side mill
End mills
Plain helical mills
Inches
Millimeter
Inch
Machine steel
.007
0.18
.006
0.15
.010
0.25
Tool steel
.005
0.13
.004
0.10
Cast iron
Bronze
.008
0.20
.009
0.23
.011
0.28
Aluminium
.013
0.33
.018
0.46

23. High speed steel cutter
Material
High speed steel cutter
Carbide cutter
ft/min
m/min
Machine steel 80 25
200 60
Tool steel 65 19
160 50
Cast iron 70 20
Bronze 90 30
300
Aluminium
750
225
1500

24. High speed steel cutter Dr. Salah Gasim Ahmed MET 103
Material
High speed steel cutter
Carbide cutter
ft/min
m/min
Machine steel 80 25
200 60
Tool steel 65 19
160 50
Cast iron 70 20
Bronze 90 30
300
Aluminium
750
225
1500
Material
Side mill
End mills
Plain helical mills
Inches
Millimeter
Inch
Machine steel
.007
0.18
.006
0.15
.010
0.25
Tool steel
.005
0.13
.004
0.10
Cast iron
Bronze
.008
0.20
.009
0.23
.011
0.28
Aluminium
.013
0.33
.018
0.46
Dr. Salah Gasim Ahmed MET 103

25. Safety precautions for milling machines
Wear safety goggles
Clean and dry the table before mounting the work holding device
Clean and dry the holding device and work piece
Mount the work piece securely
Select and mount the proper cutter to revolve in the proper direction
Clean and dry arbor cutter and collars
Use only correctly fitting wrenches on the machine
Tighten or loosen the arbor nut only with the arbor support in place (otherwise the arbor may bend)
Use the proper spindle speed, feed and depth of cut

26. Make certain that the table holding device and work piece will clear the arbor and its support during the cut.
Disengage the manual feed hand wheel when automatic feed is to be used.
Make sure that unauthorized persons are outside the safety zone of the machine when it is started.
Keep clear of the revolving cutter
Stop the cutter to remove chips and use a brush for chip removal
Release the automatic feed control when the job is completed.
Keep floor free of chips , oil and grease
When you finish working return all tools, accessories and brush the machine free of chips.

27. Dr. Salah Gasim Ahmed MET 103
Thank You
Dr. Salah Gasim Ahmed MET 103