Gear Cutting Tool Blade Back Surface Modification for Chip Flow

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Solution Overview

Problem

Chip packing during gear cutting, particularly in bevel gear manufacturing, leads to surface finish issues, blade damage, and machine tool abortion due to accumulated chips, which existing methods like compressed air or oil flushing are ineffective in addressing, especially in dry cutting processes.

Innovation Solution

Modifying the back surfaces of cutting blades with a rake angled surface and/or a hook angled surface to open up the gap between successive blades, facilitating chip removal radially or axially away from the cutting tool, optimizing chip flow and reducing chip packing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If chips are removed by compressed air or oil flushing, then chip removal is facilitated, but tool strength is reduced and process complexity increases

Engineering Contradiction:
Improvechip removalVSAvoidtool strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The back surface of the cutting blade is segmented into multiple functional zones: a rake angled surface for initial chip deflection, a hook angled surface for chip engagement and redirection, and a clearance surface for chip discharge. This segmentation allows each zone to perform a specific function in the chip removal sequence without requiring external flushing media.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces angular dimensions (rake angle and hook angle) to the back surface geometry, transforming the chip removal mechanism from a linear flushing approach to a multi-dimensional geometric control system. The rake angle creates radial chip flow while the hook angle adds axial component, achieving three-dimensional chip ejection.

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

2Ease of operation

If chip packing is eliminated by increasing gap between blades, then chip removal is improved, but tool strength is reduced

Engineering Contradiction:
Improvechip removalVSAvoidblade strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The blade geometry is modified locally at the back surface with specific angular features (rake angle of 5-15 degrees and hook angle of 10-20 degrees) while maintaining the overall blade integrity and strength. This localized geometric modification achieves chip flow control without compromising the global structural properties of the blade.

Inventive Principle:
Principle #3Local quality

3Device complexity

If dry cutting is used to maintain process simplicity, then chip packing occurs, but process complexity and cost increase with flushing systems

Engineering Contradiction:
Improveprocess complexityVSAvoidchip packing
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The cutting blade's back surface geometry serves itself to remove chips during the cutting operation. The rake angled surface and hook angled surface automatically deflect and eject chips generated during cutting without requiring external flushing systems, maintaining process simplicity while eliminating chip packing.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2152459B1Tool for improved chip flow
Publication Date: 2011.06.22 THE GLEASON WORKS
  • EP2152459B1 patent drawingFigure 1
  • EP2152459B1 patent drawingFigure 2
  • EP2152459B1 patent drawingFigure 3

AI summary

A manner of reducing or eliminating chip packing in gear cutting tools, especially in bevel gear cutting tools wherein the back surfaces (D1) of at least some cutting blades are modified by the introduction of a rake angled surface (D2) and/or a hook angled surface (D3) thereby resulting in an opening-up of the gap (86) between successive cutting blades in a direction radially or axially away from the cutting tool. Such an opening-up facilitates the removal of chips from between the cutting blades as the cutting tool rotates during cutting.