End Mill Front Cutting Edge Geometry for Chip Evacuation

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Solution Overview

Problem

Conventional end mills face difficulties in chip evacuation, leading to tool vibrations and potential damage due to curved cutting edges that can get stuck between the tool and the workpiece.

Innovation Solution

The end mill features a cutting section with radially protruding teeth having rake and clearance surfaces, and front cutting edges with chip splitting grooves that form a convex imaginary curve, ensuring improved chip evacuation and strength by avoiding sharp corners and optimizing cutting edge geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the cutting edge has a curved portion to enable radial and axial cutting, then the versatility of the end mill is improved, but chip evacuation becomes difficult and tool vibrations increase

Engineering Contradiction:
Improvecutting edge functionalityVSAvoidchip evacuation difficulty
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The cutting edge is segmented into multiple portions with different functions: a forwardly cutting portion at the front end for axial cutting, and a radially cutting portion along the axial section for radial cutting. This segmentation allows each portion to perform its specific cutting function effectively while maintaining overall versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transition between the forwardly cutting portion and the radially cutting portion is designed with a curved transition portion. This curvature enables smooth transition of the cutting edge from axial to radial cutting orientation, allowing the end mill to handle both cutting directions effectively.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the cutting edge has a curved portion for radial cutting, then the radial cutting capability is improved, but chips get stuck between the tool and workpiece causing vibrations

Engineering Contradiction:
Improveradial cutting capabilityVSAvoidtool vibration
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The cutting edge is divided into distinct functional portions: a forwardly cutting portion for axial cutting, a curved transition portion for smooth orientation change, and a radially cutting portion for radial cutting. This segmentation allows each portion to perform its specific function while maintaining overall tool stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The curved transition portion provides a smooth transition between axial and radial cutting orientations. This curvature design enables the cutting edge to effectively handle both cutting directions while maintaining stable chip flow and reducing tool vibrations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Object-generated harmful factors

If chip splitting grooves are added to the front cutting edge for chip evacuation, then chip evacuation is improved, but the strength of the cutting edge decreases

Engineering Contradiction:
Improvechip evacuationVSAvoidcutting edge strength
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

Chip splitting grooves are introduced only in specific locations along the front cutting edge where chip evacuation is most needed, rather than uniformly across the entire cutting edge. This localized modification improves chip evacuation while preserving the strength of other critical portions of the cutting edge.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4201564A1End mill
Publication Date: 2023.06.28 WALTER AG
  • EP4201564A1 patent drawingFigure 1
  • EP4201564A1 patent drawingFigure 2~3
  • EP4201564A1 patent drawingFigure 4~6

AI summary

The present invention relates to an end mill for metal cutting comprising a body (1), which body (1) comprises a cutting section (6) extending axially rearward from a front end (2), which cutting section (6) comprises a plurality of radially protruding and axially extending teeth (7). Each tooth (79 of the plurality of teeth (7) comprises a front cutting edge (13), which front cutting edge (13) extends axially rearward and radially outward from an axially most forward point (14, 14a) of the respective cutting edge (12). When the body (1) is rotated, the cutting edge (12) of each tooth (7) forms a line of intersection in a central plane containing the central longitudinal axis (4). Each front cutting edge (13) is interrupted by at least two chip splitting grooves (17) such that the line of intersection of the front cutting edge (13) with the interrupting chip splitting grooves (17) comprises outer crests (22), which each is located on an imaginary convex curve (24); at least two inner troughs (23); and curve parts (25), which each extend from one respective trough (23) of the at least two troughs (23) to one of the respective two axially closest crests (22). Each curve part (25) comprises a convexly curved outer portion (26), which extends inward from the crest (22), and has a radius (27) of curvature that, in all positions, is larger than 0,1 mm.