Shoulder Milling Insert Geometry for Stable Seat Retention
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Solution Overview
Problem
Existing cutting inserts for shoulder milling tools lack stable support, leading to potential instability during milling operations, which can result in reduced tool life and accuracy.
Innovation Solution
A cutting insert with a trigonal shape and specific geometric features, including a surface-wiping secondary cutting edge inclined relative to the median plane, negative nominal clearance angles, and flat abutment surfaces, providing increased holding moments and support within the shoulder milling tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cutting inserts with neutral or positive clearance angles are used, then the cutting edge can be formed with standard geometry, but the holding moment and stability of the cutting insert in the shoulder milling tool are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the clearance angle parameter to be negative (e.g., -5 to -15 degrees) instead of neutral or positive. This parameter change fundamentally alters the geometry of the cutting insert, enabling the abutment surface to be positioned farther from the center, thereby increasing the holding moment and improving stability without requiring additional complex structural elements
2Reliability
If the abutment surface is positioned closer to the center of the cutting insert, then the clearance angle can be neutral or positive, but the holding moment and support stability are reduced
Solution Approach 1:
The patent utilizes dimensional change by extending the abutment surface radially outward to a larger inscribed circle diameter (e.g., 10-20mm) compared to conventional designs. This dimensional extension positions the abutment surface farther from the center, creating a larger lever arm and increased holding moment, thereby improving mounting stability through spatial optimization
3Reliability
If the secondary cutting edge is parallel to the median plane, then the cutting geometry is simplified, but cutting forces do not provide sufficient inward force component to press the insert into the seat
Solution Approach 1:
The patent applies parameter changes by inclining the secondary cutting edge at a specific angle (e.g., 5-15 degrees) relative to the median plane. This angular parameter change generates a radial inward force component during cutting, which presses the cutting insert firmly into the seat, thereby improving retention and stability through force optimization
4Reliability
If the abutment area is made smaller, then the cutting insert geometry is simplified, but the support surface area for stable mounting is reduced
Solution Approach 1:
The patent utilizes dimensional change by positioning the abutment surface at a larger radial distance (larger inscribed circle) from the center. This spatial repositioning allows the abutment surface to have sufficient area for stable support while maintaining optimized clearance geometry, effectively resolving the area-stability trade-off through spatial optimization
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
Herein a cutting insert (2) and a shoulder milling tool are disclosed. The cutting insert (2) comprises a surface-wiping secondary cutting edge (28) inclined in relation to a median plane (4) of the cutting insert (2) such that a distance to the median plane (4) decreases in a direction toward a corner cutting edge (26). A circumferential surface (18) comprises a clearance surface (50) extending along a main cutting edge (24). The clearance surface (50) along the main cutting (24) edge extends at an acute angle to the median plane (4), such that the clearance surface (50) is forming a negative nominal clearance angle, and wherein the circumferential surface (18) comprises first and second abutment surfaces (90) configured for abutment against axial and/or radial support surfaces of the milling tool, the abutment surfaces (90) extending along at least part of the main cutting edge (24) and the surface-wiping secondary cutting edge (28).