Turning Theory Flashcards
What is the definition of a turning operation?
Metal removal from a revolving work to produce the required shape and size by means of a single pointed cutting tool mounted rigidly in a tool-post.
How should the workpiece be rotated?
Against the cutting edge of the tool to ensure that it do not rub against the tool
What is the definition of depth of cut?
Refers to the depth the tool’s cutting edge engages the workpiece
What is the definition of feed direction?
Refers to the direction of the tool being fed into the workpiece
What are the different types of external operation in turning?
Turning, Facing, Threading, Grooving, Parting
What are the different types of internal operation in turning?
Drilling, Reaming, Boring, Tapping
What is the angle of which tool cutting edge is set to the direction of movement in orthogonal cutting?
90 degree
Chip formation in orthogonal cutting
Form of a clock spring or a flat spiral
Forces present in orthogonal cutting
Axial Force and Tangential Force
What is the angle of which tool cutting edge is set to the direction of movement in oblique cutting?
Any angle other than 90 degree
Chip formation in oblique cutting
Twisted curl chip formation
Forces present in oblique cutting
Radial Force, Axial Force, Tangential Force
Disposal of chips in orthogonal cutting vs oblique cutting
Orthogonal cutting: Present difficulties as chip will stay on top of the tool holder and may damage the workpiece’s surface
Oblique cutting: Greatly improves the surface finish of the workpiece as it allows the chips to move freely away from the area of cutting
Which force is insignificant in oblique cutting?
Radial Force as no motion is associated with it, it does not consume power, but it influences the axial force
What are the 6 factors affecting metal cutting operation?
Cutting conditions, cutting tool material, cutting tool geometry, cutting fluids, workpiece material, machine rigidity
What is the rule of thumb (feedrate, depth of cut, cutting speed) for rough cuts?
Increase feedrate, increase depth of cut, decrease cutting speed
What is the rule of thumb (feedrate, depth of cut, cutting speed) for finishing cut?
Decrease feedrate, decrease depth of cut, increase cutting speed
What are the 6 common cutting tool material?
High Carbon Steel
High Speed Steel
Cast Cobalt Alloys
Cemented Carbide
Cemented Oxide or Ceramic
Diamond
5 reasons why throw-away inserts are becoming popular
- Worn out or broken cutting edge can be easily indexed by unclamping the locking device and rotating the insert to a new cutting tip
- Cutting tips need not be sharpened
- Setting time is minimal
- Proper clamping can be achieved easily
- Relatively cheaper to use and replace throwaway inserts