Recessed Inner Edge Geometry in Cutting Inserts for Chip Biting Suppression
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Solution Overview
Problem
Existing cutting tools face challenges in improving chip discharge control while maintaining cutting performance, particularly in shoulder machining tools, where conventional designs either neglect chip discharge or compromise on cutting edge angle, leading to poor chip management and potential chip biting.
Innovation Solution
A cutting insert design featuring a recessed inner edge with asymmetrical lengths and angles, where the longer inner edge on one side directs chips towards the tool periphery and the shorter edge on the other side ensures effective chip separation by contacting the upper surface, enhancing chip discharge control and reducing chip biting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner edge is designed with conventional symmetrical shape, then the cutting performance is maintained, but the chip discharge control is poor
Solution Approach 1:
The inner edge is designed with asymmetrical geometry where one side has a larger cutting edge angle than the other side. This asymmetry creates different chip flow paths on each side, directing chips toward the tool periphery and improving chip discharge control without requiring additional complex components.
Solution Approach 2:
Different portions of the inner edge are given different geometric properties - one side has a larger cutting edge angle for directing chips outward, while the other side has a smaller angle for effective chip separation. This localized differentiation optimizes chip discharge control across different regions of the cutting edge.
2Productivity
If the cutting edge angle is increased to improve engraving amount, then the engraving capability is enhanced, but the chip discharge control deteriorates
Solution Approach 1:
The inner edge employs asymmetrical cutting edge angles where one side has a larger angle to increase engraving capability, while the other side maintains a smaller angle to ensure proper chip discharge control. This allows the tool to achieve both high productivity and effective chip management simultaneously.
Solution Approach 2:
Different cutting edge angles are applied to different sides of the inner edge - the side requiring greater engraving capability receives a larger angle, while the side requiring better chip discharge receives a smaller angle. This localized optimization resolves the contradiction between productivity and chip discharge control.
3Strength
If the inner edge is positioned lower than the boss surface to reduce cutting resistance, then cracks are suppressed, but chip discharge control becomes poor
Solution Approach 1:
The inner edge geometry is optimized with specific cutting edge angles on each side that work in conjunction with its positioned height. Even though the inner edge is positioned lower than the boss surface to reduce cutting resistance and suppress cracks, the asymmetrical angle design ensures that chips are still effectively directed toward the tool periphery and separated, maintaining good chip discharge control.
Data Source
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AI summary
A cutting insert (10) includes an upper surface (17), a lower surface (19), a screw hole (H) having an axis (AX1) penetrating from the upper surface (17) to the lower surface (19), a peripheral side surface (15), and a major cutting edge (21), a wiper edge (24), and an inner edge (23) formed in an intersecting region between the upper surface (17) and the peripheral side surface (15). In a side view (fig. 4B) in which the peripheral side surface (15) on which the inner edge (23) is formed is seen from a direction perpendicular to the axis (AX1), the inner edge (23) includes a recessed part (23C) recessed toward the lower surface (19), a length (DL) of the inner edge (23L) on the one side of the recessed part (23C) remote from the wiper edge (24) in the side view is longer than a length (DR) of the inner edge (23R) on the other side of the recessed part (23C), a lowest point of the inner edge (23) is at a position lower than a flat part (17A) of the upper surface (17), and at least a part of the inner edge (23L) on the one side is at a position higher than the flat part (17A) of the upper surface (17). A cutting edge angle (ϕ23L, fig. 3) of the inner edge (23L) on the one side of the recessed part (23C) is larger than a half of a cutting edge angle (ϕ23R, fig. 3) of the inner edge (23R) on the other side of the recessed part (23C).