Milling Cutter With Negative Rake And Localized Wedge Angles
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Solution Overview
Problem
Existing cutting tools for end face milling of materials like wood and lightweight composites face challenges in achieving a smooth surface without pre-splitting and edge breakage, due to conflicting requirements of cutting edge angles that affect tool life and surface quality.
Innovation Solution
A cutting tool design with a negative rake angle of at least 25° to 40° for the main cutting edge and a small wedge angle for secondary cutting edges, combined with a transition area, which reduces cutting forces and prevents edge breakage, while allowing effective chip collection and tool longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wedge angle is reduced to achieve a smaller cutting edge radius and better surface finish, then surface quality is improved, but the cutting edge becomes prone to chipping and dulling
Solution Approach 1:
The cutting element has different wedge angles at different locations: a smaller wedge angle (10°-30°) at the cutting edge for surface quality, and a larger wedge angle in the body for durability. This local differentiation allows each region to optimize for its specific function.
Solution Approach 2:
The invention transitions from a two-dimensional cross-section view to a three-dimensional tapered geometry. The wedge angle varies along the length of the cutting element, creating a gradient structure that resolves the contradiction between edge sharpness and overall durability.
2Reliability
If the wedge angle is increased to improve tool life, then cutting edge durability is improved, but the rake angle and clearance angle are reduced, deteriorating machining result
Solution Approach 1:
Different sections of the cutting element have different geometric properties optimized for their specific functions. The cutting edge maintains small wedge angle for quality, while the body has larger wedge angle for tool life, resolving the trade-off.
Solution Approach 2:
The cutting element geometry is made dynamic through the tapered design, where the effective wedge angle changes along the length of the cutting edge during machining, allowing adaptation between quality and durability requirements.
3Reliability
If a negative rake angle is used to prevent edge chipping, then edge breakage is prevented, but cutting forces increase requiring higher drive power
Solution Approach 1:
The invention changes the rake angle parameter from negative to positive (0° to +15°), which reduces cutting forces and drive power requirements while maintaining edge breakage prevention through the optimized wedge angle and cutting edge radius.
Solution Approach 2:
By adjusting the wedge angle to a smaller value (10°-30°) and optimizing the cutting edge radius (0.05mm-0.5mm), the invention compensates for the positive rake angle, preventing edge chipping without requiring excessive drive power.
Data Source
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AI summary
Machining tool for face milling of non-metallic materials, in particular wood, wood-based materials and plastics as well as lightweight and composite materials made of these materials, with a base body (1) rotatable about an axis of rotation (D) and at least one row of cutting edges (S1) arranged on a circumference of the base body (1) which has at least two cutting elements (2, 3) arranged at an axial angle (λ) to the axis of rotation (D), characterized in that each cutting element (2, 3) has a secondary cutting edge (4) on the face and a main cutting edge on the circumference, that a wedge angle (β4) of the secondary cutting edge (4) in a plane perpendicular to the cutting edge (Ks) is less than 55°, and that a radial rake angle (Y602) of the main cutting edge (6) is negative with a value greater than or equal to 25°.