Face Mill Cutting Edge Geometry for High-Speed Vibration Control

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Solution Overview

Problem

Face milling cutters experience vibrations and reduced tool life due to excessive cutting forces at high speeds, leading to insufficient cutting performance and surface quality.

Innovation Solution

A face milling cutter design with a reduced setting angle of 10° to 30°, a convex main cutting edge, and a positive axial rake angle, along with a transition radius between the main and secondary cutting edges, to distribute cutting forces evenly and reduce heat generation, allowing for higher cutting speeds and improved surface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the cutting edge plunges suddenly into the workpiece at high cutting speeds, then cutting performance increases, but cutting forces become excessive causing vibrations and reduced tool life

Engineering Contradiction:
Improvecutting speedVSAvoidtool life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The main cutting edge is designed with a convex curvature instead of a straight configuration. This convex shape allows the cutting edge to gradually engage with the workpiece material, distributing the cutting force over a longer period and reducing peak forces that cause vibrations and tool failure at high cutting speeds

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The setting angle κr is reduced from the conventional 75° to between 10° and 30°. This parameter change modifies the cutting geometry to achieve a more gradual material engagement, reducing the sudden plunging effect and associated cutting force spikes that limit tool life at high speeds

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the setting angle κr is reduced to 10°-30° with a convex main cutting edge, then cutting forces are distributed better and cutting speeds can be increased to 4000 m/min, but the tool geometry becomes more complex

Engineering Contradiction:
Improvecutting speedVSAvoidtool geometry
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The setting angle κr is changed from the conventional 75° to a reduced range of 10°-30°, and the main cutting edge is given a convex profile. These parameter changes achieve the desired cutting force distribution and high-speed performance through geometric modification rather than adding complex mechanical components or control systems

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the main cutting edge is made convex to reduce cutting forces, then vibrations are reduced, but the transition to the secondary cutting edge requires precise control of the transition radius

Engineering Contradiction:
Improvevibration reductionVSAvoidtransition radius control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A transition radius of 0.5-1.5 mm is introduced between the convex main cutting edge and the secondary cutting edge. This curved transition zone ensures smooth geometric continuity, maintaining vibration reduction benefits while providing a manufacturable geometry that can be precisely controlled through standard tool manufacturing processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Temperature

If the axial rake angle is increased to 20°-30° to reduce heat generation, then dry machining becomes feasible, but the cutting edge geometry becomes more challenging to manufacture

Engineering Contradiction:
Improveheat generationVSAvoidcutting edge fabrication
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The axial rake angle is increased to a positive range of 20°-30°, which fundamentally changes the chip flow and heat generation characteristics. This parameter change enables dry machining by directing chips away from the cutting zone and reducing heat accumulation, while the geometry can be achieved through conventional tool manufacturing methods

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2542370B1Face mill and use of the same
Publication Date: 2015.05.20 GUEHRING KG
  • EP2542370B1 patent drawingFigure 1~2
  • EP2542370B1 patent drawingFigure 3~4
  • EP2542370B1 patent drawingFigure 5~6

AI summary

The face miller (12) is equipped with a plurality of plate-shaped hard material cutting inserts (20) that are distributed over the circumference. The hard material cutting inserts are located on a graduated circle in pockets (18) of a blade carrier (16) and have a main cutting edge (24), which is adjusted at a cutting edge angle (Kr) smaller than 90º relative to the working plane (26) of the miller. In order to ensure maximum machining performance at a good service life, the cutting edge angle (Kr) is selected to range between 10º and 30º, preferably between 15º and 25º, wherein the main cutting edge (24) at the same time has a slightly convex design. The main cutting edge (24) transitions into the secondary cutting edge (32) via a transition radius (R30) having a value that ranges between 0.5 and 1.5 mm. The axial rake angle (ya) ranges between 20 and 30º, preferably between 23 and 27º. According to an advantageous further development, the radial rake angle (yr) ranges between -6º and -10º, preferably between -7º and -9º.