Indexable Roughing End Mill Insert Layout for Chatter Suppression

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Solution Overview

Problem

Conventional indexable roughing end mills experience significant chattering due to resonance during cutting, leading to a rough work surface and potential chipping of cutting edges, despite existing solutions that only partially address this issue.

Innovation Solution

The indexable rotary cutting tool features a cylindrical tool body with spiral grooves and insert seats, where cutting inserts are arranged with specific angular relationships and distances to prevent simultaneous contact with the workpiece, disrupting resonance and vibration patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple cutting inserts are arranged in spiral grooves to enable large depth of cut, then productivity is improved, but chattering occurs due to resonance

Engineering Contradiction:
Improvedepth of cutVSAvoidchattering
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by arranging cutting inserts with unequal angular intervals around the tool axis. Instead of uniform distribution, the inserts are positioned at different angular positions (e.g., 0°, 90°, 180°, 270° with offset adjustments) to create asymmetric cutting patterns that disrupt resonance and reduce chattering while maintaining large depth of cut capability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent utilizes periodic action by arranging cutting inserts at specific angular intervals to create periodic cutting contacts. The inserts engage the workpiece in a controlled periodic sequence, where the timing and frequency of contacts are designed to avoid resonant frequencies, thereby reducing chattering while sustaining high productivity

Inventive Principle:
Principle #19Periodic action

2Object-affected harmful factors

If cutting inserts are arranged to suppress vibration, then chattering is reduced, but work surface smoothness is insufficient

Engineering Contradiction:
ImprovevibrationVSAvoidwork surface smoothness
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by optimizing the angular position and depth of cut for each individual cutting insert. Each insert is positioned and configured to produce locally optimal cutting conditions, with varying engagement depths and timings that collectively achieve both vibration suppression and smooth surface finish through differentiated local cutting parameters

Inventive Principle:
Principle #3Local quality

3Productivity

If cutting inserts contact workpiece simultaneously, then cutting efficiency is high, but resonance causes chipping of cutting edges

Engineering Contradiction:
Improvecutting efficiencyVSAvoidcutting edge durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the cutting process into multiple sequential stages, with each cutting insert engaging the workpiece at a different time and position. This segmented approach distributes the cutting load across multiple inserts sequentially rather than simultaneously, reducing peak forces and preventing cutting edge chipping while maintaining overall high cutting efficiency

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively suppresses chattering by ensuring cutting inserts contact the workpiece at irregular timings, reducing resonance and vibration, and enhancing surface smoothness and tool durability.

Implementation Method 1

vibration (chattering) is likely to occur due to the resonance of vibration (cutting vibration) generated during the cutting process

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3088112B1Replaceable blade edge rotary cutting tool and tool body
Publication Date: 2023.04.26 TUNGALOY CORP
  • EP3088112B1 patent drawingFigure 1
  • EP3088112B1 patent drawingFigure 2
  • EP3088112B1 patent drawingFigure 3A~3B

AI summary

An indexable roughing end mill capable of suppressing generation of chattering is provided. When the positions of cutting inserts (40) arranged in each spiral groove (28) are defined as a first segment to an nth segment (where n is an integer of 2 or higher) from a leading end surface (22) side of a tool body (20) toward a base end surface (21) side, all of the angles (β1...βm (where m is an integer of 2 or higher)) between lines connecting a rotational axis (O) and the cutting inserts (40) in the first segments of the respective spiral grooves (28) are different from each other, as viewed from the leading end surface side of the tool body (20), and an angle (αt) between the cutting insert (40) in the first segment and the cutting insert (40) in the nth segment (the uppermost segment) in a spiral groove 28 is different from any of the angles β1 ...βm (where m is an integer of 2 or higher) between the lines, as viewed from the leading end surface side of the tool body (20).