Cutting Types And Rake Angles Flashcards
What characteristics will a positive rake angle produce?
- Sharper cutting edge
- lower cutting force required -> less power consumption.
- higher surface quality and cutting speed.
What characteristics will a negative rake angle produce?
- longer tool life
- higher cutting force needed
- larger cutting depth
- lower surface quality.
What is orthogonal cutting?
When the tool is perpendicular to the direction of primary motion.
What is oblique cutting?
The tool is at an angle to the direction of primary motion.
What does single cutting point mean, and what are some examples of this?
Only one major cutting edge.
Turning, shaping, boring.
What is multipoint cutting and what are some examples of this?
More than one cutting edge.
Drilling, milling, broaching, reaming.
What is feed?
Relative movement of the tool in order to process the entire surface of the workpiece.
Under what conditions would continuous chips be formed?
-ductile material
-positive rake angle
- high cutting speeds
Under what conditions would discontinuous chips be formed?
- brittle material
- negative rake
- low cutting speeds
What does continuous with built up edge chip mean?
- long ribbon of material
- a work hardened edge
- leaves rough machined surface
Where would an external chip breaker be mounted?
Clamped to the tool face.
Where would an integral chip breaker be located?
Bulge formed into tool face. (Part of tool)
Under what conditions would chatter marks be formed?
- part vibrating causing tool to bounce
- vibration of the machine
- inconsistent material.
What are the results of chatter marks?
- low quality surface finish
- low accuracy
- damage to the tool and machine
- added noise.
What are the solutions to avoid chatter marks?
- more stable machine.
- change cutting conditions:
Speed, depth, add fluid, change feed rate.
What is the equation for turning cutting speed?
Cutting speed = Revolution speed * pi * average diameter
What application would a square thread be used for?
High axial force
What is the main strength of a general purpose thread?
It self centres
What application would a National buttress thread be used for?
One directional force
What application would a NPT pipe thread be used for?
Self tightening, self sealing
What is the equation for material removal rate for turning?
Material removal rate = cutting speed * feed * depth of cut
What is the equation for cutting time for turning?
Cutting time = length / feed rate
What is the difference between slab and face milling
Slab milling - parallel plane to axis of cutter
Face milling - right angle to rotation of cutter
What is slot milling?
Creating a narrow ridge in the part
