Advanced Turning
Effects of change in the tool geometry
The cutting edge angles in turning affect various cutting factors. It is important to understand what effect each angle has.
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End cutting
edge angle
Side cutting
edge angle
Cutting edge
inclination angle
True rake angle
Side flank angle
True rake angle
Side flank angle
Side cutting edge angle
End cutting edge angle
Cutting edge inclination angle
True rake angle
The true rake angle greatly affects cutting resistance, chip discharge, cutting temperatures and tool life.
Larger
Smaller
Effects
- Sharpness increases.
- Increase of 1°.
- Decreases cutting resistance by 1%.
- A small true rake angle increases cutting resistance.
Workpiece
characteristics
- Soft
- Easy to machine material.
- Hard.
Cutting conditions, etc.
- Lack of rigidity of workpiece and machine.
- Cutting edge strength is required.
Side flank angle
The side flank angle avoids friction between the tool flank face and workpiece and leads the cutting edge into the component.
Larger
Smaller
Effects
- Flank wear decreases.
- Cutting edge strength increases.
Workpiece
characteristics
- Soft
- Easy to machine material.
- Hard.
Cutting conditions, etc.
-
- Cutting edge strength is required.
Side cutting edge angle
The side cutting edge angle reduces impact load and affects the amount of feed force, back force and chip thickness.
Larger
Smaller
Effects
- Chip control worsens.
- Tool life lengthens.
- Long, thin workpieces can bend.
-
Workpiece
characteristics
- Hard with high heat generation.
- Long and thin.
Cutting conditions, etc.
- Rigid machine and workpiece.
- Lack of machine rigidity.
- Finishing at small depths of cut.
End cutting edge angle
The end cutting edge angle avoids interference between the machined surface and the tool (end cutting edge). Usually 5° ~ 15°.
Larger
Smaller
Effects
-
- Cutting edge strength increases.
- Heat is easily generated at the cutting edge.
- The back force increases, causing vibration.
Workpiece
characteristics
-
-
Cutting conditions, etc.
- Finishing.
- Heavy cutting.
Cutting edge inclination angle
Angle of inclination of the rake face. During heavy machining, the initial impact on the cutting edge at the start of a cut is very large. The cutting edge inclination angle is used for reducing the stress on the top cutting edge to avoid fracturing. For turning, 3° ~ 5° is recommended, and for milling, 10° ~ 15° is recommended.
Larger
Smaller
Effects
- Chips are discharged on the opposite side of a workpiece.
- Chips are discharged towards the workpiece side.
- Cutting edge strength increases.
- The back force increases and easily causes vibration.
Workpiece
characteristics
-
-
Cutting conditions, etc.
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-
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