Cutting Force and Heat: The larger the rake angle, the smaller the cutting deformation and friction, resulting in reduced cutting force, power, and heat. For every 1° increase in the rake angle, the cutting force decreases by approximately 1%, and this effect is more significant when machining plastic materials.​

Cutting Edge Strength and Heat Dissipation: Increasing the tool rake angle makes the cutting edge sharper but reduces its strength and heat dissipation volume, leading to easy chipping. A negative rake angle enhances impact resistance and heat dissipation, suitable for hard materials or intermittent cutting.​

Chip Morphology and Chip Breaking: A large  rake angle makes chips difficult to break (needing chip breakers); a small rake angle promotes chip brittle fracture.​

Machined Surface Quality: A large rake angle inhibits built-up edges and vibration, improving surface quality; a negative rake angle may cause vibration and reduce quality.

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Key Selection Principles of Tool Rake Angle​

Workpiece Material: Plastic materials (steel, aluminum alloy) → 10°~30°; brittle materials (cast iron, bronze) → 5°~15°; extra-hard materials (hardened steel) → -20°~-5°.​

Tool Material: High-speed steel → 5°~10° larger than carbide; carbide → small/negative rake angle; ceramic/CBN → -15°~-4°.​

Machining Conditions: Rough machining/intermittent cutting → small/negative rake angle; finish machining → large rake angle; poor rigidity/insufficient power → large rake angle; CNC/automated lines → small rake angle for stable life.

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Positive Rake Angle with Chamfer: Enhances cutting edge strength, suitable for carbide rough machining/intermittent cutting.​

Negative Rake Angle Type: Good impact resistance and heat dissipation, suitable for high-strength hard materials.​

Curved Surface Type (with Chip Breaker): Promotes chip breaking, suitable for plastic materials.

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