Double-Sided Negative Milling Insert With Near-90° Entering Angle
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Solution Overview
Problem
Double-sided negative cutting inserts for milling face challenges due to their negative axial and radial tipping-in angles, which increase the difficulty of the cutting process and result in an entering angle less than 90°, affecting efficiency and tool wear.
Innovation Solution
A double-sided negative cutting insert with a quadratic basic shape and 90° rotational symmetry, featuring depressed central side surfaces on main side faces, which improves the entering angle closer to 90° and provides better clearance and stability, reducing the risk of tool damage and improving machining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative axial tipping-in angle is given to the cutting insert to create relief behind the active surface-wiping cutting edge, then clearance is improved, but the cutting process becomes heavier and more difficult
Solution Approach 1:
The patent changes the geometric parameters of the cutting insert by providing a positive axial tipping-in angle (contrary to conventional negative angles) and specific radial tipping-in angles, thereby altering the cutting geometry to achieve both good clearance and easier cutting process. The main cutting edges are given a downward slope to counterbalance the positive axial tipping-in angle, optimizing the entering angle to approach 90°.
2Reliability
If a negative radial tipping-in angle is given to the cutting insert to create relief behind the active main cutting edge, then clearance is improved, but the entering angle becomes smaller than 90° affecting efficiency
Solution Approach 1:
The patent optimizes the radial tipping-in angle parameters (αr1 and αr2) to specific ranges (0° to 15° and 0° to 30° respectively) and combines them with a positive axial tipping-in angle and downward sloping main cutting edges. This parameter optimization ensures the entering angle approaches 90°, maximizing cutting efficiency while maintaining adequate clearance through the balanced geometric configuration.
3Reliability
If the entering angle is kept smaller than 90° due to negative tipping-in angles, then clearance behind cutting edges is improved, but cutting efficiency decreases
Solution Approach 1:
The patent fundamentally changes the tipping-in angle parameters from conventional negative values to positive axial tipping-in angles combined with optimized radial tipping-in angles. The main cutting edges are given a downward slope to counterbalance the positive axial angle, ensuring the entering angle approaches 90°. This parameter transformation simultaneously achieves both objectives: adequate clearance behind cutting edges and high cutting efficiency.
4Ease of manufacture
If a double-sided negative cutting insert is designed with conventional geometry, then manufacturing is simple and cost-efficient, but the cutting process is heavier and tool wear increases
Solution Approach 1:
The patent maintains the simple quadratic basic shape and negative overall geometry of conventional inserts for easy manufacturing, but optimizes the specific geometric parameters: positive axial tipping-in angle, controlled radial tipping-in angles, and downward sloping main cutting edges. This selective parameter optimization preserves manufacturing simplicity while dramatically improving cutting process ease and reducing tool wear.
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 1e~1f
AI summary
A double-sided negative cutting insert for use in milling with quadratic basic shape and eight different working positions. The cutting insert (1) comprises a peripheral surface (10), which extends around the cutting insert between first and second major faces (2, 3) and has four main side faces (11a-11d). One main cutting edge and one surface-wiping cutting edges are formed at an intersection between each main side face and the first major face (2) and at an intersection between each main side face and the second major face (3). Each main side face comprises a first lateral side surface (13), a central side surface (14) and a second lateral side surface (15) arranged one after the other between two corner side faces (12) with the central side surface (14) located between the first and second lateral side surfaces (13, 15), wherein the central side surface is slightly depressed in relation to the adjacent first and second lateral side surfaces.