Star-Shaped Cutting Insert for Dual Chamfering

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Solution Overview

Problem

Existing rotary milling cutters lack a efficient and indexable solution for performing both front and back chamfering operations with a high number of indexable positions, especially for non-hole and hole chamfering tasks.

Innovation Solution

A star-shaped cutting insert with a centrally located axis and alternating outer and inner corner portions is designed for a rotary milling cutter, allowing for front and back chamfering with increased indexability and the ability to perform non-hole and hole chamfering, featuring a cutting edge configuration that includes front and back chamfering edges on each cutting portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional cutting inserts are used for front and back chamfering, then the tool can perform basic chamfering operations, but the number of indexable positions is limited

Engineering Contradiction:
Improvenumber of indexable positionsVSAvoidinsert geometry complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cutting insert is divided into multiple cutting portions (at least three) arranged around the insert axis, with each portion having its own cutting edges for front and back chamfering. This segmentation allows the insert to provide multiple indexable positions while maintaining a manageable geometric configuration for each individual cutting portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cutting insert employs asymmetric geometry with alternating outer and inner corner portions at different radii from the insert axis. This asymmetric star-shaped configuration enables increased indexability while differentiating between active cutting portions and non-active portions, resolving the contradiction between versatility and complexity.

Inventive Principle:
Principle #4Asymmetry

2Adaptability or versatility

If a single cutting insert is used for both front and back chamfering, then tool complexity is reduced, but the ability to perform both operations effectively is compromised

Engineering Contradiction:
Improvedual chamfering capabilityVSAvoidcutting edge configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each cutting portion on the insert is designed with cutting edges that can perform both front chamfering and back chamfering operations. The insert achieves multi-functionality by having at least three cutting portions with alternating active and non-active configurations, allowing a single insert to handle both chamfering directions effectively.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The solution moves from a two-dimensional cutting edge configuration to a three-dimensional star-shaped insert with cutting portions arranged around the insert axis. This dimensional change enables the insert to provide both front and back chamfering capabilities while managing the complexity through spatial distribution of cutting edges.

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

3Adaptability or versatility

If alternating outer and inner corner portions are used, then indexability is increased, but the manufacturing complexity of the insert increases

Engineering Contradiction:
Improveindexable positionsVSAvoidinsert manufacturing
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The insert manufacturing process is simplified by segmenting the insert into repeating cutting portion units. Each cutting portion follows a standardized geometric pattern with outer and inner corner portions, allowing for modular manufacturing approaches that reduce overall complexity despite the increased indexability requirements.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3481574A1Star-shaped cutting insert for a front and back chamfering rotary milling cutter
Publication Date: 2019.05.15 ISCAR LTD

AI summary

A front and back chamfering rotary milling cutter (20) includes a cutter body (22) including an insert pocket (30) and a star-shaped indexable cutting insert (32) releasably retained in the pocket (30). The cutting insert (32) has star-shaped upper and lower surfaces (42, 44) connected by a peripheral surface (46) intersecting each of the upper and lower surfaces (42, 44). The cutting insert (32) includes a plurality of circumferentially alternating inner and outer corner portions (50, 52). A cutting portion (54) is defined by each outer corner portion (50) together with an adjacent first inner corner portion (52a) rotationally forward thereof and an adjacent second inner corner portion (52b) located rotationally rearward thereof. Each cutting portion (54) includes a front chamfering cutting edge (58a) extending from the outer corner portion (50) to the first inner corner portion (52a) and a back chamfering cutting edge (58b) extending from the outer corner portion (50) to the second inner corner portion (52b).