Thread Milling Tool Clearance Surface for Stable Low-Vibration Cutting

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Solution Overview

Problem

Prior thread milling cutting tools are prone to vibrations, leading to insufficient surface finish and potential damage, due to either excessive digging into the workpiece material with large clearance angles or high friction with small clearance angles.

Innovation Solution

The thread milling cutting tool features a unique clearance surface design with a smaller radial clearance angle at the cutting edge and a larger angle further behind, providing improved stability and reduced pressure from the workpiece, thereby minimizing vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a large radial clearance angle is used on the clearance surface, then the tool is easier to cut, but the tool digs deep into the workpiece material causing uneven cutting and vibrations

Engineering Contradiction:
Improveease of cuttingVSAvoidcutting stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The clearance surface is designed with varying radial clearance angles at different locations: a smaller angle near the cutting edge for stability and support, and a larger angle further away for reduced pressure and easier cutting. This local variation in geometric properties resolves the contradiction between ease of cutting and cutting stability.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If a small radial clearance angle is used on the clearance surface, then the tool stability is improved, but cutting and friction forces increase causing the tool to diverge from the intended path

Engineering Contradiction:
Improvetool stabilityVSAvoidcutting and friction forces
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The clearance surface is designed with varying radial clearance angles at different locations: a smaller angle near the cutting edge for stability and support, and a larger angle further away for reduced pressure and easier cutting. This local variation in geometric properties resolves the contradiction between ease of cutting and cutting stability.

Inventive Principle:
Principle #3Local quality

3Device complexity

If a constant radial clearance angle is used on the clearance surface, then the tool design is simplified, but the tool is prone to vibrations due to either excessive digging or high friction

Engineering Contradiction:
Improveclearance surface design complexityVSAvoidcutting stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The clearance surface is designed with varying radial clearance angles at different locations: a smaller angle near the cutting edge for stability and support, and a larger angle further away for reduced pressure and easier cutting. This local variation in geometric properties resolves the contradiction between ease of cutting and cutting stability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4155018A1Thread milling cutting tool
Publication Date: 2023.03.29 WALTER AG
  • EP4155018A1 patent drawingFigure 1
  • EP4155018A1 patent drawingFigure 2
  • EP4155018A1 patent drawingFigure 3

AI summary

The present invention relates to a thread milling cutting tool for metal cutting comprising an elongated main body, which main body (1) comprises a cutting section (5) which extends axially rearward from a front end (2) and comprises a plurality of teeth (7). The plurality of teeth (7, 22) comprises at least a first set (6) of circumferentially spaced teeth (7), wherein each tooth (7) of the at least first set has a same, first axial distance (8) to the front end, and a clearance surface (14) of each tooth (7) has a radial clearance angle. The clearance surface (14) of each tooth (7) of the at least first set (6) of teeth comprises a rotationally leading portion (16) and a rotationally trailing portion (17), wherein the leading portion (16) extends from and rotationally behind the cutting edge (15), and the radial clearance angle (α) of the leading portion (16) is smaller than the radial clearance angle (β) of the trailing portion (17).