Tangential Cutting Insert Structure for Stable Deep Shoulder Milling

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Solution Overview

Problem

Long edge milling cutters experience reduced tool life due to large and varying cutting forces, leading to insert movement, wear, and plastic deformation, especially in deep shoulder milling applications, where existing solutions fail to provide sufficient stability and indexable cutting edges.

Innovation Solution

A tangential cutting insert with three flat support surfaces on each side, recessed to provide a positive rake angle and stable fixation, allowing for efficient distribution of cutting forces and enhanced cutting performance, along with a milling tool design that supports these inserts with corresponding contact surfaces to constrain movement and reduce load on the seat contact surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a long edge milling cutter is used for deep shoulder milling applications, then the metal removal capacity and productivity are improved, but the cutting forces become large and varying, causing insert movement, wear, and plastic deformation that reduce tool life

Engineering Contradiction:
Improvemetal removal capacityVSAvoidtool life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cutting insert is divided into multiple functional surfaces: three flat support surfaces (first, second, and third) on each side surface, a main surface, and rake surfaces. This segmentation allows each surface to perform a specific function - the flat surfaces distribute cutting forces to prevent movement and deformation, while the rake surfaces enable effective cutting. The triangular configuration with three indexable cutting edges per side provides six total cutting edges, improving productivity through indexing while maintaining reliability through force distribution.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the cutting insert is inadequately supported in the insert seat, then the device complexity is reduced, but the insert moves under large cutting forces, generating poor surface quality and increased wear

Engineering Contradiction:
Improveinsert seat structureVSAvoidsurface quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The cutting insert features three flat support surfaces on each side surface, creating localized contact points with the insert seat. This local quality enhancement at the support surfaces provides precise constraint and force distribution without requiring complex overall insert seat structures. The flat surfaces ensure stable support and accurate positioning, maintaining surface quality while keeping the device complexity low.

Inventive Principle:
Principle #3Local quality

3Productivity

If the insert seat contact surfaces are subjected to large and varying cutting forces, then the productivity is improved through deep cutting depths, but the contact surfaces undergo plastic deformation and deteriorate, reducing tool life

Engineering Contradiction:
Improvecutting depth capabilityVSAvoidinsert seat service life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The support function is segmented into three distinct flat support surfaces on each side of the insert, each contacting a corresponding contact surface in the insert seat. This segmentation distributes the large and varying cutting forces across multiple localized contact points rather than concentrating them on a single surface, reducing plastic deformation and extending the service life of the insert seat while maintaining deep cutting capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The three flat support surfaces create localized contact regions with the insert seat that are optimized for force distribution. This local quality enhancement at the contact interfaces allows the insert seat to withstand large cutting forces during deep shoulder milling without undergoing excessive plastic deformation, thereby extending its durability while maintaining productivity.

Inventive Principle:
Principle #3Local quality

4Stability of the object's composition

If a tangential cutting insert with opposing seating surface is used, then the support stability is improved, but the number of indexable cutting edges is limited to two

Engineering Contradiction:
Improveinsert support stabilityVSAvoidnumber of indexable cutting edges
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The insert geometry is segmented into three flat support surfaces on each side surface, arranged in a triangular configuration. This segmentation allows the insert to maintain stable support through the flat surfaces while providing three indexable cutting edges on each side (six total), overcoming the limitation of conventional two-edge designs. The triangular arrangement optimizes both stability and productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support function is transitioned from a single opposing seating surface to three flat support surfaces distributed on the side surfaces of the insert. This dimensional change from a single-plane support to a multi-surface triangular configuration provides both stable support and additional cutting edges, enabling six indexable edges while maintaining insert stability during deep shoulder milling.

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

Data Source

PatentEP3593928B1A tangential cutting insert and a milling tool
Publication Date: 2021.02.24 SANDVIK COROMANT
  • EP3593928B1 patent drawingFigure 1a~1b
  • EP3593928B1 patent drawingFigure 2a~2d
  • EP3593928B1 patent drawingFigure 3a~3d

AI summary

The present invention relates to a tangential cutting insert (1) for a milling tool, the tangential cutting insert (1) comprising two opposing main surfaces (2, 3) having a triangular shape and three identical side surfaces (4) extending between the main surfaces (2, 3), wherein the tangential cutting insert (1) includes at least three identical and indexable major cutting edges (5) formed at the intersection of at least one of the main surfaces (2, 3) and the three identical side surfaces (4). Each side surface (4) includes three flat support surfaces (6, 7, 8) being recessed in relation to the major cutting edge (5) and arranged one after another in a longitudinal direction (9) of each side surface (4), wherein a first flat support surface (6) is disposed at a centre of each side surface (4) and is forming the lowermost recessed support surface (6) in relation to the major cutting edge (5), wherein second and third flat support surfaces (7, 8) are located on opposite sides of the first flat support surface (6) and extend at an obtuse angle (β) with the first flat support surface (6). In addition, the invention relates to a milling tool (11) having a plurality of insert seats (13) configured to receive the tangential cutting insert (1).