Stepped Cutting Insert Geometry for Stable Chip Curling
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Solution Overview
Problem
Conventional cutting inserts experience issues with chip curling and stability, particularly at low feed rates, resulting in inconstant chip radius and tangled chips due to the convex shape of the first breaker protrusion.
Innovation Solution
A polygonal cutting insert design featuring a corner portion with first and second raised portions, a main breaker with a concave lower inclined surface, and auxiliary blade protrusions to effectively curl and discharge chips, reducing contact area with the workpiece and enhancing chip handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a convex-shaped first breaker protrusion is located close to the cutting edge, then the chip breaker structure is simple, but during low-speed feeding chips are not properly curled resulting in inconstant chip radius and tangled chips
Solution Approach 1:
The first breaker protrusion is divided into multiple segments: a first convex portion close to the cutting edge and a second convex portion farther away. This segmentation allows each portion to perform different functions - the first portion handles initial chip contact while the second portion ensures proper curling, resolving the contradiction between structural simplicity and chip curling reliability.
Solution Approach 2:
The breaker protrusion uses curved surfaces instead of simple convex shapes. The first and second convex portions have specific curvature radii that guide chips through a controlled curling path. This curvature design ensures stable chip radius even at low feed rates, improving reliability while maintaining reasonable structural complexity.
2Ease of manufacture
If the first breaker protrusion is simply formed in a convex shape, then manufacturing is easy, but chip curling is unstable at low feed rates
Solution Approach 1:
Dividing the breaker protrusion into first and second convex portions with different functions maintains manufacturing feasibility while achieving precise chip control. The segmented design allows each portion to be optimized for its specific role in the chip curling process.
Solution Approach 2:
The invention specifies particular parameter ranges for the convex portions (curvature radii, distances from cutting edge, heights) to optimize chip curling. These parameter changes enable consistent chip radius control at low feed rates while keeping the manufacturing process practical.
3Force
If chips are not properly curled, then cutting resistance increases, but chip discharge becomes difficult leading to clogging
Solution Approach 1:
The curved surfaces of the first and second convex portions create a guided curling path for chips. This curvature ensures chips are properly formed and discharged, preventing clogging while maintaining acceptable cutting resistance levels.
Solution Approach 2:
The second convex portion acts as an intermediary element that receives chips from the first convex portion and guides them into proper curl. This intermediate structure ensures smooth chip flow and discharge, preventing both excessive resistance and clogging.
Data Source
AI summary
A cutting insert according to the present disclosure includes a first raised portion and a second raised portion stepped from the first raised portion, which are formed on a top surface and along a center line connecting the center of the corner portion and the center of the top surface. The first raised portion is located closer to the corner portion than the second raised portion is, and the first raised portion is inclined downwardly from the second raised portion toward the corner portion. The second raised portion is formed at a higher position from the bottom surface than the first raised portion, and a side portion connected to the first raised portion is inclined downwardly from the second raised portion toward the first and second cutting edges.