CNC Cutting Tools and Tooling 1 — Questions and Answers
Question 1: What is the primary purpose of the rake angle on a cutting tool?
- To increase tool rigidity
- To control chip flow and cutting forces (Correct answer)
- To determine the tool's coating type
- To set the tool height above center
Correct answer: To control chip flow and cutting forces
The rake angle controls how the chip flows away from the cutting edge and directly affects cutting forces and tool life.
Question 2: Which carbide insert designation describes a triangular insert shape?
- S
- T (Correct answer)
- C
- R
Correct answer: T
In the ISO insert designation system, 'T' denotes a triangular (equilateral triangle) insert shape with three cutting edges.
Question 3: What is the main advantage of using coated carbide inserts over uncoated ones?
- Lower cost per insert
- Improved chip breaking only
- Increased hardness and wear resistance at elevated temperatures (Correct answer)
- Reduced need for coolant
Correct answer: Increased hardness and wear resistance at elevated temperatures
Coatings like TiN, TiAlN, and Al2O3 significantly improve hardness and thermal resistance, extending tool life and allowing higher cutting speeds.
Question 4: In end mill selection, what does the term 'helix angle' refer to?
- The taper of the shank
- The angle of the flutes relative to the tool axis (Correct answer)
- The number of cutting edges
- The tool's reach below the holder
Correct answer: The angle of the flutes relative to the tool axis
The helix angle is the angle of the flutes (cutting edges) relative to the tool's central axis, affecting chip evacuation and cutting forces.
Question 5: What type of end mill is best suited for cutting aluminum at high speeds?
- 4-flute carbide end mill
- 2-flute high-helix end mill (Correct answer)
- Ball-nose end mill with TiN coating
- Cobalt steel end mill
Correct answer: 2-flute high-helix end mill
A 2-flute high-helix end mill provides large flute valleys for superior chip evacuation, which is critical when cutting aluminum at high speeds.
Question 6: What is the purpose of a center-cutting end mill designation?
- The tool can be used for thread milling
- The tool can plunge directly into material (Correct answer)
- The tool has reinforced center core
- The tool is designed for centerline profiling only
Correct answer: The tool can plunge directly into material
A center-cutting end mill has a cutting edge that extends to the center, allowing it to plunge directly into the workpiece like a drill.
CNC Cutting Tools and Tooling 1
What is the primary purpose of the rake angle on a cutting tool?