Re-Grindable Power Skiving Insert Geometry for Longer Tool Life

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Solution Overview

Problem

Power skiving cutting inserts have limited tool life and are expensive, particularly for large modules, necessitating a solution for extended use and cost-effective manufacturing.

Innovation Solution

A cutting insert with a specific geometry featuring a relief surface with positive nominal relief angles and a cutting edge profile that remains unchanged after re-grinding, allowing for multiple reuse without additional machining, and is designed for power skiving of metallic workpieces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If exchangeable cutting inserts are used for power skiving, then tool readjustment time is reduced and manufacturing efficiency is improved, but the cutting inserts are expensive and have limited tool life

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidtool life
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The cutting insert is designed to be re-grinded multiple times to restore the cutting edge geometry. The relief surface is configured with specific subsurfaces and transition regions that allow material to be removed through grinding while maintaining the original cutting edge profile, enabling the insert to be recovered and reused rather than discarded after single use

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The relief surface is pre-configured with specific geometric features including first and second relief subsurfaces with positive nominal relief angles and a corner relief subsurface with continuous transitions. This preliminary geometric configuration enables the cutting edge to maintain its profile after grinding operations, allowing multiple reuse cycles without additional machining operations

Inventive Principle:
Principle #10Preliminary action

2Productivity

If large dimension cutting inserts are used for machining splines or teeth in module range above 5, then the required cutting performance is achieved, but the cost of cutting inserts increases significantly

Engineering Contradiction:
Improvecutting performanceVSAvoidinsert cost
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The cutting insert design enables multiple reuse cycles through systematic re-grinding of the relief surface. By configuring the relief surface with specific subsurfaces and transition regions, the insert can have material removed and still maintain functional cutting edge geometry, effectively recovering the insert value rather than discarding it after limited use

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The nominal relief angle parameter is configured to be positive and vary across different regions of the relief surface. This parameter variation allows the cutting edge geometry to be maintained after grinding operations, enabling the insert to withstand multiple reuse cycles while maintaining cutting performance

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4252948A1Power skiving tool and re-grindable cutting insert therefor
Publication Date: 2023.10.04 SANDVIK COROMANT
  • EP4252948A1 patent drawingFigure 1~3
  • EP4252948A1 patent drawingFigure 4~6
  • EP4252948A1 patent drawingFigure 7~11

AI summary

The invention relates to a cutting insert (1) for a power skiving tool. The insert (1) comprises - a first side (2) including a rake face (5), - a second side (3) opposite the first side (2), - a peripheral surface (4) extending between the first side (2) and the second side (3), wherein the peripheral surface (4) includes a relief surface (6) comprising a first relief subsurface (61), a second relief subsurface (62) and a corner relief subsurface (63), and - a cutting edge (7) arranged at the intersection between the relief surface (6) and the rake face (5), the cutting edge (7) including a first flank edge (71), a second flank edge (72) and a nose edge (73), wherein the cutting edge (7) is arranged or substantially arranged in a first plane (P) and has a cutting edge profile. In each point of the cutting edge (7), the relief surface (6) is arranged such that a nominal relief angle (α) of each of the first relief subsurface (61), the second relief subsurface (62) and the corner relief subsurface (63) is positive and has a maximum value (αmax) in a first point (P1) along the nose edge (73). The relief surface (6) is furthermore arranged such that, when seen in a section plane through the cutting insert (1) and in parallel to the first plane (P), an intersection formed by the section plane, on one hand, and the first relief subsurface (61), the second relief subsurface (62) and the corner relief subsurface (63) on the other hand, has a profile that is identical or substantially identical to the cutting edge profile. The invention also relates to a power skiving tool comprising such cutting insert.