Variable-Chamfer Cutting Insert for Push-Pull Machining Accuracy
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Solution Overview
Problem
Existing cutting inserts are limited to push cutting and suffer from high cutting resistance and tool life issues when used for pull cutting, leading to chattering, chipping, and fracture due to inadequate design of the chamfer and cutting edge geometry.
Innovation Solution
A cutting insert with a surface comprising cBN sintered material, ceramics, or cermet, featuring a rake face, flank face, and a chamfer with a minimum width along the connecting cutting edge portion, and a balanced chamfer width distribution for push and pull cutting edges to reduce thrust and feed force components, enhancing tool life and machining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the chamfer width is increased to reduce cutting resistance and improve tool life, then the thrust force component increases leading to chattering and reduced machining accuracy
Solution Approach 1:
The chamfer width is varied locally along the cutting edge: wider chamfer at the nose portion for reduced cutting resistance and longer tool life, narrower chamfer at the connecting portion for reduced thrust force and chattering. This local differentiation resolves the contradiction between tool life and machining accuracy.
Solution Approach 2:
The chamfer width parameter is changed along the length of the cutting edge, transitioning from a uniform width to a variable width with minimum width at the connecting portion. This parameter change optimizes both tool life and machining accuracy by balancing thrust force and cutting resistance.
2Device complexity
If the chamfer width is uniform along the cutting edge, then the structure is simple, but it causes high cutting resistance and chipping in pull cutting operations
Solution Approach 1:
Different sections of the cutting edge are given different chamfer widths: the nose portion has a wider chamfer for pull cutting durability, while the connecting portion has a narrower chamfer for reduced thrust force. This local differentiation improves cutting edge integrity without excessive complexity.
Solution Approach 2:
The cutting edge is segmented into different functional portions (nose portion and connecting portion) with different chamfer characteristics. This segmentation allows each portion to be optimized for its specific function, improving overall reliability.
3Manufacturing precision
If the chamfer width is reduced to minimize thrust force and chattering, then machining accuracy improves, but cutting resistance increases and tool life decreases
Solution Approach 1:
The chamfer width is optimized locally: narrower at the connecting portion for reduced thrust force and chattering (improving accuracy), wider at the nose portion for reduced cutting resistance (improving tool life). This resolves the contradiction between accuracy and tool life.
Solution Approach 2:
The chamfer width parameter transitions from uniform to variable, with minimum width at the connecting portion and increased width at the nose portion. This parameter optimization simultaneously improves machining accuracy and extends tool life.
Data Source
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AI summary
A cutting insert has a surface that relates to cutting, the surface comprising cBN sintered material, ceramics, or cermet. The cutting insert comprises: a rake face; a flank face; a chamfer located between the rake face and the flank face; and a cutting edge formed by a ridgeline at which the flank face and the chamfer intersect. The cutting edge comprises a cutting edge portion for push cutting, a cutting edge portion for pull cutting, and a connecting cutting edge portion located between the cutting edge portion for push cutting and the cutting edge portion for pull cutting. In the chamfer located along the cutting edge, the chamfer located along the connecting cutting edge portion has a minimum width.