Threading Insert Edge Roundness Variation for Wear and Vibration

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Solution Overview

Problem

Existing threading inserts face challenges in reducing wear and improving surface quality due to vibrations and high cutting forces during metal cutting operations, particularly in threading processes where multiple passes are required, and there is a need for more efficient material removal and enhanced thread profile quality.

Innovation Solution

A threading insert with a cutting edge that has varying edge roundness along its length, specifically with a greater roundness for the leading and trailing edges compared to the top edge, which is achieved through abrasive processes like blasting or EDM, allowing for optimized cutting forces and reduced wear, thereby improving tool life and surface finish.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cutting edge has a constant edge roundness, then the manufacturing process is simple, but the wear resistance and surface quality cannot be optimized for different cutting zones

Engineering Contradiction:
Improvewear resistanceVSAvoidedge roundness variation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating different edge roundness values at different locations along the cutting edge. The leading cutting edge has a first edge roundness, the top cutting edge has a second edge roundness, and the trailing cutting edge has a third edge roundness. This allows each zone to be optimized for its specific function: the leading edge for initial contact and chip formation, the top edge for maximum material removal, and the trailing edge for final surface finishing, thereby improving overall wear resistance and surface quality without requiring complex adjustable mechanisms.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the cutting edge has sharp edges, then the initial cutting ability is high, but vibrations increase and surface quality deteriorates

Engineering Contradiction:
Improvesurface qualityVSAvoidvibrations
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the edge roundness parameter across different zones of the cutting edge. Instead of a uniform sharp edge that causes vibrations, the patent introduces controlled rounding with specific radius values (R1, R2, R3) at different locations. The leading edge may have a smaller roundness for initial cutting, while the top and trailing edges have larger roundness values to reduce vibrations and improve surface quality. This parameter variation allows the cutting edge to maintain cutting effectiveness while minimizing harmful vibrations.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If the edge roundness is increased at the top cutting edge, then the wear resistance is improved for radial cutting, but the cutting forces may increase

Engineering Contradiction:
Improvetool lifeVSAvoidcutting forces
Core Design Contradiction:
Duration of action of moving objectVSForce

Solution Approach 1:

The patent applies local quality by selectively increasing edge roundness at the top cutting edge (second edge roundness R2) while maintaining different roundness values at the leading (R1) and trailing (R3) edges. This localized modification optimizes the top cutting edge for radial cutting operations where wear resistance is critical for tool life, while the other zones maintain their specific roundness characteristics to balance cutting forces and material removal efficiency.

Inventive Principle:
Principle #3Local quality

4Manufacturing precision

If multiple threading passes are used, then complex thread profiles can be manufactured, but the process time increases and productivity decreases

Engineering Contradiction:
Improvethread profile qualityVSAvoidthreading speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by optimizing the edge roundness parameters (R1, R2, R3) to enable more efficient material removal during threading operations. The varied roundness configuration allows for better chip formation and reduced cutting forces, which can reduce the number of passes required or allow for higher feed rates. This parameter optimization improves productivity while maintaining the ability to manufacture complex thread profiles with high precision.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The varying edge roundness design reduces wear and vibrations, enhances surface quality, and allows for more efficient material removal, leading to longer tool life and improved thread profile quality, especially in operations like modified flank infeed and radial infeed threading.

Implementation Method 1

a beam comprising an abrasive medium is directed towards the first cutting edge; and altering at least one blasting parameter as the beam moves along the first cutting edge

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 2

achieved through abrasive processes like blasting or EDM

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Data Source

PatentEP3498405B1Threading insert having variable edge roundness
Publication Date: 2022.08.17 SANDVIK INTELLECTUAL PROPERTY AB
  • EP3498405B1 patent drawingFigure 1~2
  • EP3498405B1 patent drawingFigure 3~5
  • EP3498405B1 patent drawingFigure 6~7

AI summary

A threading insert (1) comprising a top surface (2), an opposite bottom surface (3), a side surface (4) connecting the top surface (2) and the bottom surface (3), a first tooth (5), the first tooth (5) comprising a first cutting edge (6), the first cutting edge (6) comprising a first top cutting edge (7) connecting a first leading cutting edge (8) and a first trailing cutting edge (9), the first cutting edge (6) has an edge roundness, the size of the edge roundness varies along the first cutting edge (6).