Dual-Nose Internal Turning Tool for Chip Evacuation and Tool Life

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Solution Overview

Problem

Existing turning tools for internal longitudinal metal cutting face challenges with poor chip breaking and evacuation, especially at cutting depths equal to or less than the nose radius, leading to increased wear and inefficiencies in roughing and finishing operations.

Innovation Solution

A turning tool design with two nose cutting edges positioned on opposite sides of the longitudinal axis, featuring acute and obtuse entering angles for improved chip evacuation and reduced wear, allowing for both roughing and finishing with a single tool by reversing the feed direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single turning insert with one nose cutting edge is used for internal longitudinal turning, then the tool structure is simple and cost-effective, but chip breaking and evacuation are poor especially at cutting depths equal to or less than the nose radius

Engineering Contradiction:
Improvetool structureVSAvoidchip evacuation
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The turning tool is divided into two separate turning inserts, each with its own nose cutting edge optimized for specific cutting conditions. The first turning insert has a first nose cutting edge with first cutting parameters, while the second turning insert has a second nose cutting edge with second cutting parameters, allowing each segment to address specific chip evacuation challenges at different cutting depths

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution introduces a new dimension to the tool design by adding a second turning insert with a nose cutting edge positioned at a different radial distance from the rotational axis than the first nose cutting edge. This dimensional variation enables effective chip breaking and evacuation at cutting depths that would be problematic with a single nose radius

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

2Manufacturing precision

If longitudinal turning is performed in two or more passes with different cutting portions, then roughing and finishing quality are improved, but using two separate turning tools increases cost and time consumption

Engineering Contradiction:
Improvesurface qualityVSAvoidcycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The turning tool is designed with multi-functionality by incorporating two turning inserts with different nose cutting edges on the same tool body. The first nose cutting edge is optimized for roughing operations while the second nose cutting edge is optimized for finishing operations, allowing both functions to be performed with a single tool rather than requiring separate tools for each operation

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

Solution Approach 2:

The tool design allows dynamic selection of cutting edges based on operational requirements. The operator can switch between the first and second nose cutting edges depending on whether roughing or finishing is required, enabling adaptive optimization of cutting parameters for different stages of the machining process

Inventive Principle:
Principle #15Dynamics

3Productivity

If a turning tool with optimized nose radius is used for roughing, then material removal rate is improved, but tool wear increases and tool life decreases

Engineering Contradiction:
Improvematerial removal rateVSAvoidtool life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The turning tool is segmented into two distinct turning inserts, each with nose cutting edges optimized for different operational requirements. One insert is optimized for roughing with parameters that maximize material removal rate, while the other insert is optimized for finishing with parameters that minimize tool wear and extend tool life

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different local qualities are applied to the two nose cutting edges through their respective cutting parameters. The first nose cutting edge has parameters suited for aggressive material removal during roughing, while the second nose cutting edge has parameters optimized for precise finishing with reduced wear, allowing each local cutting zone to have the optimal properties for its specific function

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3456442B1A turning tool and method for metal cutting
Publication Date: 2025.08.06 SANDVIK INTELLECTUAL PROPERTY AB
  • EP3456442B1 patent drawingFigure 1~2
  • EP3456442B1 patent drawingFigure 3~5
  • EP3456442B1 patent drawingFigure 6~8

AI summary

A turning tool (1) for internal turning of a metal work piece (18), comprising a rear end (3), an opposite forward end (4) and a longitudinal center axis (A1) extending therebetween, a first nose cutting edge (5) comprising a first radially distal point (10) having an associated first rake face (16), the first nose cutting edge (5) separating and connecting a first forward cutting edge (12) and a first rearward cutting edge (14), the turning tool (1) comprises a second nose cutting edge (6) comprising a second radially distal point (11) having an associated second rake face (17), the second nose cutting edge (6) separating and connecting a second forward cutting edge (13) and a second rearward cutting edge (15), the first and second radially distal points (10, 11) being positioned on opposite sides or substantially opposite sides relative to the longitudinal center axis (A1), the first and second rake faces (16, 17) facing opposite directions, the second radially distal point (11) being positioned ahead of the the first radially distal point (10), the first forward cutting edge (12) forming an acute first entering angle (α), the second forward cutting edge (13) forming an obtuse second back clearance angle (β), and the second rearward cutting edge (15) forming an acute second entering angle (δ).