The distinction among the angles of a milling cutter primarily includes the rake angle, relief angle, main cutting edge angle, auxiliary cutting edge angle, and cutting edge inclination. These angles significantly impact the milling cutter's cutting performance, service life, and machined quality. Below is a detailed explanation of these angles and the practical significance of distinguishing them.
Distinguishing Milling Cutter Angles
- Rake Angle:
- Definition: The rake angle is the angle formed between the leading edge of the cutting blade and the line of the cutter body.
- Classification: Radial rake angle and axial rake angle. The radial rake angle mainly affects cutting power, while the axial rake angle influences chip formation and the direction of axial force.
- Significance: The size of the rake angle directly affects the sharpness and strength of the cutting edge. A larger rake angle reduces cutting forces and temperatures, improving cutting efficiency but weakening the cutting edge, suitable for soft materials and high-efficiency cutting. A smaller rake angle is suitable for hard materials, maintaining high cutting edge strength.
- Relief Angle:
- Definition: The relief angle is the angle formed between the trailing edge of the cutting blade and the line of the cutter body.
- Significance: The size of the relief angle determines the tangential load the milling tool experiences during cutting. A smaller relief angle is suitable for rough machining or processing materials with high strength and hardness, ensuring sufficient tool strength. A larger relief angle is suitable for processing materials with high plasticity or elasticity, reducing friction between the tool's flank face and the workpiece, improving machining accuracy.
- Main Cutting Edge Angle:
- Definition: The main cutting edge angle is the angle between the cutting edge and the cutting plane.
- Classification: Milling cutters have various main cutting edge angles, such as 90°, 88°, 75°, 70°, 60°, and 45°.
- Significance: The main cutting edge angle significantly affects radial cutting forces and cutting depths. A smaller angle reduces radial cutting forces, improves vibration resistance, but decreases cutting depths. Larger angles are suitable for rough planar milling, reducing cutting forces and improving cutting stability.
- Auxiliary Cutting Edge Angle:
- The auxiliary cutting edge angle is the angle between the other side of the cutting edge (opposite to the main cutting edge angle) and the cutting plane, mainly affecting tool strength and heat dissipation.
- Cutting Edge Inclination:
- Definition: The cutting edge inclination is the angle between the cutting edge and the base plane.
- Significance: The cutting edge inclination controls the direction of chip flow. An appropriate inclination ensures easy chip ejection, preventing chip accumulation during cutting, thereby ensuring machining quality.
Practical Significance of Distinguishing Angles
- Enhanced Cutting Efficiency: Proper selection of milling cutter angles reduces cutting forces and temperatures, improving cutting efficiency.
- Extended Tool Life: Suitable angle combinations strengthen the tool, reducing wear and breakage, thereby extending tool life.
- Guaranteed Machining Quality: Correct angle selection ensures smooth chip ejection, avoiding excessive cutting edge wear and built-up edge formation, improving machining accuracy and surface quality.
- Adaptation to Various Machining Needs: Different workpiece materials and machining requirements demand different milling cutter angle combinations. Distinguishing milling cutter angles meets various machining needs, improving efficiency and flexibility.
In summary, distinguishing among the angles of a milling cutter is crucial for enhancing cutting efficiency, extending tool life, guaranteeing machining quality, and adapting to various machining needs. Therefore, when selecting and using milling cutters, it is essential to choose the appropriate angle combination based on specific machining conditions and requirements.
