Gear Tooth Flank Chamfering to Reduce Burrs on Both End Faces

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Solution Overview

Problem

Existing methods for chamfering flank edges of teeth on cylindrical toothed workpieces result in burr formation when chamfering in a direction from the tooth tip to the tooth root, especially with worn cutting edges, and require repositioning of the workpiece for complete chamfering of both end faces.

Innovation Solution

A method using one or more milling tools with predefined rotational relationships and axial movements to chamfer flank edges from the tooth root to the tooth tip, allowing simultaneous chamfering of both end faces without repositioning, utilizing a single tool with dual cutting edges that switch functions based on rotation direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If chamfering is performed from the tooth tip to the tooth root, then the machining process follows conventional approach, but burr formation occurs especially with worn cutting edges

Engineering Contradiction:
Improveconventional machining approachVSAvoidchamfer quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional chamfering direction by machining from the tooth root toward the tooth tip instead of the traditional tooth tip to tooth root approach. This inversion eliminates burr formation at the tooth root and maintains chamfer quality even with worn cutting edges, as the cutting edge progresses from the root outward along the tooth flank.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If a single milling tool is used to chamfer one end face, then the tool configuration is simple, but the workpiece must be repositioned to chamfer the opposite end face

Engineering Contradiction:
Improvetool configurationVSAvoidworkpiece repositioning time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The milling tool is designed with multiple cutting edges that can chamfer both end faces of the workpiece. By rotating the workpiece 180 degrees between machining operations, a single tool performs the chamfering function on both end faces, eliminating the need for tool changes or complex multi-tool configurations while reducing repositioning time.

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

3Manufacturing precision

If the workpiece is repositioned to chamfer both end faces, then complete chamfering is achieved, but production time increases

Engineering Contradiction:
Improvecomplete chamfering coverageVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The machining process maintains continuous useful action by chamfering both end faces in sequence without interruption. The workpiece is rotated 180 degrees between end face machining operations, allowing the same cutting edge to continuously perform chamfering on both surfaces without stopping the machining cycle, thereby maximizing productivity while ensuring complete chamfering coverage.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4368325B1Method for chamfering flank edges of teeth on a cylindrical toothed workpiece
Publication Date: 2025.07.30 SANDVIK COROMANT
  • EP4368325B1 patent drawingFigure 1~3
  • EP4368325B1 patent drawingFigure 4a~4b
  • EP4368325B1 patent drawingFigure 5~8

AI summary

A method for chamfering the flank edges (61, 62) of teeth on a cylindrical toothed workpiece (8) at an end face (9a) of the workpiece by means of at least one milling tool (1), wherein the workpiece (8) and the milling tool (1) are rotated with a predefined relationship between the speed of rotation of the milling tool and the speed of rotation of the workpiece and with the axis of rotation of the milling tool in parallel with the a central axis (4) of the workpiece and wherein the milling tool is moved along a predefined path in relation to the workpiece such that each one of the flank edges (61, 62) at this first end face (9a) of the workpiece (8) is chamfered in a machining direction from the tooth root to the tooth tip of the associated tooth.