Cutting Insert Recessed Rake Structure for Feed-Flexible Chip Flow

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Solution Overview

Problem

Conventional cutting inserts face challenges in chip discharge during high-feed and low-feed machining operations, particularly in high-depth-of-cut conditions, with insufficient chip control and adaptability, especially during low-feed machining.

Innovation Solution

A cutting insert with a prismatic cutting edge body featuring a front cutting edge, side cutting edge, recessed parts, and a wall part with a wavy and discrete wall surface, which allows for improved chip control by lifting thick chips during high-feed operations and deforming thin chips during low-feed operations, enhancing freedom of feed and chip discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a projection for chip control is formed on a rake surface of a cutting tool main body, then chip control is improved, but the distance between cutting point and projecting portion depends on sintered body size, limiting dimensions and cutting edge length

Engineering Contradiction:
Improvechip controlVSAvoidadaptability to low depth cutting and low-feed operation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The invention transitions from a two-dimensional flat rake surface to a three-dimensional recessed structure with multiple levels. The recessed part creates vertical dimensionality that allows chip control surfaces to act on chips at different depths and positions, enabling effective chip control across varying cutting depths and feed rates without being constrained by sintered body dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The rake surface is segmented into multiple functional zones: a first rake surface, a second rake surface, and a third rake surface arranged at different positions and orientations. This segmentation allows each surface to control chips under different cutting conditions, providing adaptability across a wide range of machining parameters including low depth cutting and low-feed operation.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the sintered body has a flat upper surface, then manufacturing is simplified, but chips cannot be controlled during low depth cutting or low-feed operation

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidchip control during low depth cutting
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The invention creates a dynamic chip control system where the recessed part and multiple rake surfaces can adapt to varying chip thicknesses and feed rates. The three-dimensional structure allows different portions of the rake surfaces to engage with chips depending on cutting conditions, providing dynamic adjustment without changing the fundamental sintered body manufacturing process.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If an indented chip breaker is disposed in parallel to the side cutting edge, then chip control is provided, but adaptability to low-feed machining (finishing) is insufficient

Engineering Contradiction:
Improvechip controlVSAvoidadaptability to low-feed machining
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The recessed part is positioned asymmetrically relative to the side cutting edge, and the multiple rake surfaces are arranged at different angles and positions. This asymmetric configuration allows the chip control structure to effectively engage with chips under low-feed conditions where symmetric or parallel arrangements would be ineffective. The asymmetric design provides sensitivity to varying feed rates and chip flow patterns.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4049774A1Cutting insert
Publication Date: 2022.08.31 TUNGALOY CORP
  • EP4049774A1 patent drawingFigure 1
  • EP4049774A1 patent drawingFigure 2
  • EP4049774A1 patent drawingFigure 3

AI summary

Chip discharge during high-feed machining and low-feed machining particularly in a high-depth-of-cut state or the like is improved so as to allow socalled freedom of feed during cutting to be improved. A cutting edge body (30) of a cutting insert (10) includes a front cutting edge (31) formed on one end side in a longitudinal direction, the front cutting edge being a cutting edge formed on an intersecting edge between a peripheral side surface and an upper surface of the cutting edge body having a prismatic shape, a side cutting edge (32) formed on one end side in a lateral direction, a recessed part provided in the upper surface of the cutting edge body to be subsequent to the side cutting edge in the lateral direction, and a wall part (34) having a wavy wall surface formed in a portion of the recessed part and a discrete wall surface formed at a position between the wavy wall surface and the side cutting edge and including a plurality of surfaces which are discrete along the longitudinal direction.