Double-Sided Milling Insert Asymmetric Clearance Angles
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Solution Overview
Problem
Existing double-sided cutting inserts for milling face milling tools face challenges in achieving a soft cut and stable milling process due to limitations in design freedom and effective rake angles, leading to issues with chip formation and wear protection.
Innovation Solution
A double-sided cutting insert with a square basic shape and beveled corners, featuring alternately arranged main and plane cutting edges, positive nominal plane relief angles, and negative nominal main clearance angles, allowing for a specific installation position that provides a large positive effective axial angle for soft machining and reliable protection of inactive cutting edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cutting insert is tilted at a negative axial angle and negative radial angle to protect inactive cutting edges, then wear protection of inactive cutting edges is improved, but the effective rake angle becomes restricted and chip formation deteriorates
Solution Approach 1:
The cutting insert employs asymmetric clearance surface designs where the first and second main clearance surfaces have different orientations relative to the axis of symmetry. This asymmetry allows the insert to achieve both protective tilting angles and adequate effective rake angles by creating non-uniform clearance geometry that compensates for the restrictive installation angles.
Solution Approach 2:
The patent changes the clearance angle parameters of the main clearance surfaces, specifically designing them with angles that differ from conventional symmetric designs. By adjusting these geometric parameters, the insert maintains stability and edge protection while improving chip formation through optimized effective rake angles at the cutting edges.
2Ease of manufacture
If the cutting insert uses a symmetric design with equal clearance angles, then manufacturing simplicity is improved, but design freedom is restricted and milling process stability deteriorates
Solution Approach 1:
The cutting insert deliberately breaks symmetry by designing main clearance surfaces with different orientations and angles. The first main clearance surface and second main clearance surface are arranged asymmetrically relative to the axis of symmetry, providing enhanced milling process stability while remaining manufacturable through standard indexing positions.
Solution Approach 2:
Different regions of the cutting insert are given different clearance surface properties. The main clearance surfaces adjacent to different main cutting edges have different orientations and angles, allowing each cutting edge to operate with optimized local geometry for its specific cutting position and function.
3Reliability
If the cutting insert is designed with large negative radial installation angle, then protection of inactive cutting edges is improved, but effective axial angle becomes limited and peeling machining behavior is reduced
Solution Approach 1:
The patent optimizes the clearance angle parameters of the main clearance surfaces to compensate for large negative radial installation angles. By carefully selecting and adjusting these angular parameters, the insert achieves both edge protection and adequate effective axial angles that enable peeling machining behavior.
Solution Approach 2:
The asymmetric arrangement of main clearance surfaces allows different cutting edges to have different effective geometries. This asymmetry enables the insert to maintain protective installation angles while providing at least some cutting edges with sufficient effective axial angles for peeling machining.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a double-sided cutting insert for milling, comprising: a top side (2), a bottom side (4), a circumferential lateral surface (6), a first cutting edge (8), which is formed at a transition from the top side (2) to the circumferential lateral surface (6), a second cutting edge (10), which is provided at a transition from the bottom side (4) to the circumferential lateral surface (6), an axis of symmetry (S) relative to which the cutting axis has a rotational symmetry of order 4, and a reference plane (R) running normal to the axis of symmetry (S) and dividing the cutting insert into two halves. The first cutting edge (8) and the second cutting edge (10) each have: main cutting edge portions (12) and face cutting edge portions (14) arranged in alternation, which extend between raised cutting corners (16) and lowered cutting corners (18), which are closer to the reference plane (R) than the raised cutting corners (16). The circumferential lateral surface (6) has face free surfaces (24), which extend along the face cutting edge portion (14) and which approach the axis of symmetry (S) with increasing distance from the associated face cutting edge portion (14). The circumferential lateral surface (6) has main free surfaces (22), which extend along the main cutting edge portion (12) and which move further away from the axis of symmetry with increasing distance from the associated main cutting edge portion (12).