Single-sided four-way indexable cutting insert for small diameter milling

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Solution Overview

Problem

Existing small diameter tool holders for insert mills are limited by two-way indexable inserts, which are less competitive with solid end mills due to reduced cutting edge length and increased wear, making them less efficient for 90° shoulder milling operations.

Innovation Solution

A single-sided four-way indexable cutting insert with a basic square shape and specific design features, including a rake surface, unground lower sub-surface, and overhanging portions, allowing for four indexable positions and reduced material usage, enabling efficient 90° shoulder milling operations in small diameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If two-way indexable inserts are used in small diameter tool holders, then the insert design is simpler, but the cutting edge length is reduced and wear increases, making them less competitive with solid end mills

Engineering Contradiction:

Improveinsert design complexityVSAvoidcutting edge length and efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The insert is divided into four distinct indexable positions with two adjacent cutting edges on each side, allowing the cutting edge to be segmented into different functional zones (main cutting portion and wiper portion) that can be independently utilized during indexing operations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each cutting edge is designed to perform multiple functions: the main cutting portion performs primary material removal while the wiper portion provides surface finishing, and after indexing, the previously worn wiper portion becomes a fresh main cutting edge, enabling the same physical edge to serve different purposes throughout its lifecycle

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If four-way indexable inserts are used with traditional wiper design, then more indexable positions are available, but the cutting edge length is reduced due to the need for relieved portions

Engineering Contradiction:

Improvenumber of indexable positionsVSAvoidcutting edge length

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The cutting edge is designed with dimensional variation along its length, creating distinct zones (main cutting portion and wiper portion) that utilize different spatial relationships with the workpiece, allowing the full edge length to be effectively used across multiple indexing positions without requiring traditional relieved portions

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Area of stationary object

If small diameter inserts are used, then the insert mill can operate in smaller locations, but distortion during manufacturing increases

Engineering Contradiction:

Improvemilling location sizeVSAvoidinsert distortion

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The insert geometry parameters are specifically optimized for small diameters, with the cutting edge length and wiper portion dimensions scaled appropriately to minimize manufacturing distortion while maintaining functionality, allowing precise manufacturing of small diameter inserts without excessive distortion

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10406609B2Single-sided four-way indexable positive cutting insert and insert mill therefor

Publication Date: 2019.09.10 ISCAR LTD

AI summary

A single-sided four-way indexable cutting insert includes a positive basic shape, a rake surface, a peripheral surface including four side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has an imaginary square frustum which defines a square base containing the cutting insert's base bearing surface, and further defines four isosceles trapezoid side surfaces respectively containing the cutting insert's four side abutment surfaces. A material volume VF of the cutting insert and a void volume VS of the insert fulfill the condition VS/VF≥0.25.