1. Manufacturing Rounded Shapes
Processes

2. Examples of Lathed Parts

3. Outline Types of Processes Turning Parameters Lathe Components
Geometry
Material Removal Rate
Forces
Lathe Components
Lathe Attachments
Design Considerations
Types of Lathes

4. Types of Processes Turning Facing Form Tools Boring Drilling Parting
Threading
Knurling

5. Various Turning Operations

6. Turning Operation

7. Turning Parameters Geometry Forces in Turning Material Removal Rate
side rake angle
back rake angle
relief angles
cutting-edge angles
nose radius
Forces in Turning
cutting force
thrust force
These forces cannot be calculated accurately; they are determined by experiments
Material Removal Rate

8. Lathe Tool Parameters

9. Lathe Tools

10. Lathe Tool Inserts

11. Lathe Tool Holders

12. Lathe Feed and Speed V = πDN/12 V = cutting speed in ft/min;
Velocity at which the tool head moves along the workpiece surface
D = diameter of the rotating tool or rotating workpiece
N = RPM of the rotating tool or rotating workpiece
Feeds for a lathe are listed as in/rev or m/rev. Multiply these by the RPM to obtain the feed in in/min or m/min.

13. Lathe Feed and Speed Example: Work Material: Aluminum
Tool Material: High Speed Steel
Workpiece Diameter: in
Recommended Cutting Speed:
600 ft/min
N = 12V/πD
N=12*600/(π*3.375)
=679.2 RPM
The closest available speed on the lathe, without exceeding this value, is 630 RPM so this value should be used.
Recommended Feed for HSS/aluminum = in/rev
f = ( )*630 RPM = in/min

14. Material Removal Rate
Material Removal Rate (MRR) is the volume of workpiece material removed per unit time
MRR = πDavgdf N
Davg = average diameter
=(Doriginal + Dfinal)/2
= (Doriginal - d)
d = depth of cut
f = feed, in/rev or mm/rev
N = RPM

15. Material Removal Rate Example: Original Diameter = 3.375 in
RPM = 630 RPM
Feed = .01 in/rev
Depth of cut = .02 in
MRR = πDavgdfN
Davg = = in
MRR = π*3.355*.02*.01*630
= 1.33 in3/min

16. Lathe Components Bed Carriage Headstock Tailstock
dead center
live center
Feed Rod and Lead Screw

17. Lathe Components

18. Example of a Lathe

19. Centers

20. Lathe Attachments
Chucks
Collets
Face Plates
Mandrels
Accessories

21. Chucks

22. Lathe Attachments

23. Collets

24. Mandrels

25. Design Considerations
Design parts so they can be fixtured or clamped easily
Design the part so that tolerances of the dimensions and finishes are as large as possible
Avoid tapers, sharp corners, and large variations in the dimensions of the part
Produce blanks as close to the final design as possible
Design the workpiece so that the cutting tools can move across it without obstructions
Standard cutting tools should be able to machine the design
Select materials that can be machined properly

26. Types of Lathes Tracer Lathes Automatic Lathes Automatic Bar Machines
Turret Lathes
Computerized Lathes

27. Turret Lathe Operations

28. Turret Lathes and Computerized Lathes

29. Example of a Turret Lathe

30. Vertical Turret Lathe

31. Summary
Various processes are available to create different shapes and surface effects
Several different fixtures exist to hold a workpiece in a lathe
A workable design must be considered in order to allow efficient machining

32. The End
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