Cutting Insert Clearance Geometry for Edge Damage Resistance
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Solution Overview
Problem
Conventional cutting inserts with positive clearance angles on major cutting edges are prone to damage during high-load machining due to excessive initial load when biting into a workpiece, making them unsuitable for robust cutting conditions.
Innovation Solution
The cutting insert features a unique design with major cutting edges having a first clearance angle changing portion that reduces to a negative value and a second portion that increases to a positive value, combined with a protruding portion that increases thickness and reduces clearance angle, enhancing edge strength and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a positive clearance angle is provided for the major cutting edges, then the cutting insert can process wall surfaces effectively, but the cutting edge is easily damaged when biting into the workpiece due to excessive initial load
Solution Approach 1:
The clearance angle is segmented into two distinct zones: a first clearance angle zone near the corner edge and a second clearance angle zone away from the corner edge. This segmentation allows each zone to have optimized clearance angles suited for its specific function, resolving the contradiction between wall surface processing and biting durability.
Solution Approach 2:
Different clearance angle values are applied to different locations on the cutting edge. The first clearance angle (smaller value) is applied near the corner edge where biting occurs, while the second clearance angle (larger value) is applied away from the corner edge for wall surface processing. This local differentiation optimizes performance for each specific function.
2Reliability
If the cutting edge is made thinner to reduce initial load during biting, then damage resistance improves, but the structural strength and stability of the cutting insert decreases
Solution Approach 1:
The cutting insert structure is optimized locally at the corner edge region where biting occurs. The first clearance angle zone creates a localized geometry that reduces stress concentration and initial load during biting, while the rest of the insert maintains sufficient thickness and strength for overall structural integrity.
Solution Approach 2:
The cutting edge is divided into functional zones with different geometric characteristics. The first clearance angle zone near the corner provides biting optimization, while the second clearance angle zone provides structural strength, allowing the insert to withstand both biting loads and machining loads.
Data Source
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AI summary
An object of this disclosure is to provide a cutting insert that is shaped so that a major cutting edge is not damaged easily. In the cutting insert, a major cutting edge, a corner edge, a flat cutting edge and an inner cutting edge are formed on at least an upper surface, a protruding portion protruding outward is formed in a major cutting edge side surface portion of a side surface that corresponds to the major cutting edge, and a first section is formed in which, when viewed from above, the protrusion amount becomes smaller as the protruding portion separates from the corner edge. Furthermore, the cutting insert includes a first clearance angle changing portion in which a clearance angle becomes smaller as a major cutting edge flank portion formed in a major cutting edge side surface portion separates from the corner edge, and a second clearance angle changing portion in which the clearance angle becomes larger as the major cutting edge flank portion separates from the corner edge, wherein the first clearance angle changing portion is preferably positioned closer to the corner edge than the second clearance angle changing portion is, and, of end portions of the first clearance angle changing portion, the value of the clearance angle at a distal end portion from the corner edge is preferably negative.