Tapered-Waist Indexable Insert for Stable High-Feed Milling

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Solution Overview

Problem

Existing double-sided indexable high-feed and drilling inserts face challenges in tool life expectancy, depth of cut, plunging depth, tool ramping angles, and abutment stability due to limitations in design, particularly with non-winged and winged insert geometries.

Innovation Solution

A double-sided indexable insert with a tapered-waist geometry, featuring 180-degree rotational symmetry, converging inward and outward abutment surfaces, and a through clamping bore, optimized for improved abutment stability and cutting performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a non-winged high-feed insert design is used, then the insert structure is simple, but the tool life expectancy and depth of cut are limited

Engineering Contradiction:
Improveinsert structureVSAvoidtool life expectancy
Core Design Contradiction:
Device complexityVSDuration of action of moving object

Solution Approach 1:

The insert is divided into multiple functional zones: cutting portions with cutting edges, front abutment surfaces for stability, side abutment surfaces for pocket engagement, and a tapered waist portion. This segmentation allows each zone to perform its specific function optimally, improving overall tool life while maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert transitions from a two-dimensional flat design to a three-dimensional geometry with a tapered waist and converging abutment surfaces. This dimensional change enables better pocket engagement and increased depth of cut capability without significantly increasing structural complexity

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

2Length of moving object

If a winged high-feed insert design is used, then the cutting edge length and depth of cut increase, but the insert has a narrow portion spanning across its longitudinal length reducing stability

Engineering Contradiction:
Improvecutting edge lengthVSAvoidinsert stability
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The insert features curved converging abutment surfaces that taper toward the center, creating a tapered waist geometry. This curved design provides structural continuity and strength throughout the longitudinal length, eliminating the narrow weak portion found in winged designs while maintaining extended cutting edge length

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The geometry parameters of the insert are optimized with specific convergence angles for the abutment surfaces and a controlled taper ratio. These parameter changes ensure that the cutting edge length is maximized while the tapered waist maintains sufficient thickness for stability throughout the insert's longitudinal span

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If the winged extensions are made longer to increase cutting depth, then the cutting performance improves, but the risk of breakage increases

Engineering Contradiction:
Improvecutting depthVSAvoidbreakage resistance
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The convergence angle of the abutment surfaces and the taper ratio of the waist are optimized to provide the necessary structural support for extended cutting depths. By carefully controlling these geometric parameters, the insert achieves increased cutting depth capability while maintaining breakage resistance through adequate material thickness throughout the structure

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If parallel straight side abutment surfaces are used, then the insert design is simple, but the abutment stability in the pocket is insufficient

Engineering Contradiction:
Improveabutment surface geometryVSAvoidabutment stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The side abutment surfaces are designed as converging curved surfaces that taper toward the center of the insert, creating a tapered waist geometry. This curved design provides better engagement with the tool pocket, increasing abutment stability without significantly increasing geometric complexity

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The abutment surfaces feature asymmetric convergence angles optimized for specific machining operations. The front abutment surfaces and side abutment surfaces have different geometric characteristics tailored to their respective functions, improving overall stability while maintaining design simplicity

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3717166B1Double-sided indexable insert having tapered waist for high-feed milling and drilling
Publication Date: 2022.03.23 ISCAR LTD
  • EP3717166B1 patent drawingFigure 1A~3
  • EP3717166B1 patent drawingFigure 4
  • EP3717166B1 patent drawingFigure 5~8

AI summary

An indexable milling or drilling insert (14, 114, 214) having a 180- degree rotational symmetry about each of the first, second and third axes (X, Y, Z) of a three-dimensional euclidean space. The insert (14, 114, 214) has opposite first and second main surfaces (18, 20) and a peripheral surface (22) extending therebetween. Each main surface (18, 20) has a main abutment surface (33) and at least two rake surfaces (58). The insert (14, 114, 214) has a through clamping bore (28) which extends along the third axis (Z) and opens out to the main surfaces (18, 20). The peripheral surface (22) has two opposite front surfaces (36) connected to two opposite side surfaces (34). Each front surface (36) has a pair of outward abutment surfaces (44) and each side surface (34) has a pair of at least partially planar inward abutment surfaces (40). Each pair of outward abutment surfaces (44) converge outwardly away from the third axis (Z) and each pair of inward abutment surfaces (40) converge inwardly towards the third axis (Z).