End Mill Cutting Edge Geometry for Axial Plunging Stability

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Solution Overview

Problem

Conventional milling tools are limited in their ability to perform effectively during axial plunging, have high feed forces, and compromise cutting performance during operations like ramping and helical milling, especially when processing difficult-to-machine materials like high-strength steels or cast irons, and lack universality in machining operations.

Innovation Solution

The milling tool design features a cutting edge section that drops continuously from the cutter end to the central axis, with ground-in end pockets and a central cutting edge that reaches near the axis, allowing for effective perpendicular plunging and improved centering, along with a manufacturing method that forms these features using simple kinematics between the milling tool blank and grinding wheel, enhancing stability and chip clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional milling tool designs are used, then the tool is suitable for inclined plunging or ramping, but it has too high feed forces when plunging purely axially into a workpiece

Engineering Contradiction:
Improveaxial plunging capabilityVSAvoidfeed forces
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The cutting edge is segmented into multiple sections with different geometries: radially outer end cutting sections for ramping operations and cutting edge sections dropping to the central axis for axial plunging. This segmentation allows each section to be optimized for its specific function, reducing feed forces during axial plunging while maintaining effectiveness in inclined operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the cutting edge are given different local geometries and properties. The cutting edge sections that drop continuously to the central axis have optimized angles and shapes specifically for axial plunging, while the radially outer sections maintain geometry suitable for ramping. This local differentiation resolves the contradiction by providing the right cutting geometry in the right location.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the cutting edge sections drop continuously to the central axis, then axial plunging performance improves, but cutting performance during ramping and helical milling deteriorates

Engineering Contradiction:
Improveaxial plunging performanceVSAvoidmetal removal rate
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The cutting edge is divided into functionally distinct segments: radially outer end cutting sections for ramping/helical milling and cutting edge sections dropping to the central axis for axial plunging. This segmentation enables the tool to maintain high metal removal rates during ramping while also achieving effective axial plunging, as each segment performs its designated function optimally.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The milling tool achieves multi-functionality by incorporating cutting edge geometries that perform both axial plunging and inclined ramping/helical milling effectively. The continuous drop of cutting edge sections to the central axis, combined with properly designed radially outer sections, creates a universal tool that maintains high productivity across different machining operations.

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

3Productivity

If ground-in end pockets are used to create free face, then chip clearance improves, but manufacturing complexity increases

Engineering Contradiction:
Improvechip clearanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The manufacturing process merges multiple functions into a single grinding operation. The grinding process simultaneously creates the end pockets for chip clearance, forms the cutting edge sections with correct geometry, and establishes the continuous drop profile. This merging of operations reduces manufacturing complexity while achieving the desired chip clearance and cutting edge geometry.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grinding process is designed to perform multiple functions simultaneously: forming end pockets, creating cutting edge geometry, and establishing the continuous drop profile. This multi-functional approach simplifies manufacturing by reducing the number of separate operations required, while still achieving excellent chip clearance through the formed end pockets.

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

Data Source

PatentEP3797911B1Shaft milling device and method of manufacturing the same
Publication Date: 2022.06.08 GUEHRING KG
  • EP3797911B1 patent drawingFigure 1
  • EP3797911B1 patent drawingFigure 2~3
  • EP3797911B1 patent drawingFigure 4~5

AI summary

A milling tool, particularly in the configuration of an end mill, is described, comprising a cylindrical shank section with a central axis, to which a cylindrical cutting section (20) is attached, featuring at least three circumferential cutting edges (22) arranged in a spiral shape and separated from one another by flutes (24). The circumferential cutting edges extend via cutting edge corner regions (26) into substantially radially extending end cutting edges (28, 30, 40), which, following radially outer end cutting sections (28), each slope away from the end mill face towards the central axis (AM) with a cutting section (30) formed by ground end pockets (32). To expand the operating range of the milling tool, the cutting section (30) slopes continuously towards the central axis (AM).In the area of ​​the milling cutter core (36), it is formed by a point (38) introduced into the end pocket (32), with which a central cutting edge (40) extending to the area near the central axis (AM) is produced. Furthermore, a particularly economical method for manufacturing the milling tool is presented.