Negative Cutting Insert With Tangential Chamfer

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Solution Overview

Problem

Negative cutting inserts for machining operations face issues with wear and vibrations, leading to reduced accuracy and shorter tool life, as well as increased noise and surface roughness due to uneven wear patterns and reaction forces during turning and milling operations.

Innovation Solution

The introduction of a chamfer extending from the cutting edge to the clearance side, making an angle of 1°-10° or 3°-8°, which reduces vibrations and flank wear, allowing for longer tool life and improved machining accuracy by applying the insert tangentially to the workpiece, and optionally incorporating a convex wiper edge and boron nitride material for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rounded part is provided to improve wear resistance and suppress breaking, then the wear resistance of the clearance side is improved, but vibrations and noise during machining increase

Engineering Contradiction:
Improvewear resistanceVSAvoidvibrations and noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the geometric parameters of the clearance side by introducing a chamfer with specific angle (1°-10° or 3°-8°) and extension length (0.03mm-0.30mm), replacing the conventional rounded part design. This parameter change modifies the contact mechanics between the insert and workpiece, reducing vibrations and noise while maintaining wear resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The chamfer is applied locally at specific regions of the clearance side rather than uniformly rounding the entire edge. This localized modification allows the insert to maintain structural integrity and wear resistance in critical areas while reducing harmful vibrations and noise through the chamfered surfaces.

Inventive Principle:
Principle #3Local quality

2Productivity

If the insert is used for extended periods to reduce disposal costs, then productivity is improved, but machining accuracy deteriorates due to flank wear

Engineering Contradiction:
Improvetool lifeVSAvoidmachining accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The chamfer geometry parameters (angle and extension length) are optimized to control the wear pattern on the clearance side. This parameter optimization allows the insert to maintain acceptable flank wear levels for extended periods while preserving machining accuracy within tolerance ranges.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The chamfer is pre-formed on the insert before machining operations begin. This preliminary geometric feature prepares the insert to distribute contact stresses and control wear progression from the outset, enabling extended tool life while maintaining accuracy throughout the tool's service life.

Inventive Principle:
Principle #10Preliminary action

3Object-generated harmful factors

If a larger chamfer extension is used to further reduce vibrations, then vibrations are reduced, but the machining region and productivity are reduced

Engineering Contradiction:
ImprovevibrationsVSAvoidmachining region
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The chamfer extension length is optimized within a specific range (0.03mm-0.30mm) to achieve the best balance between vibration reduction and maintaining adequate machining region. This parameter optimization ensures that the chamfer is sufficient to reduce vibrations and noise while not excessively reducing the active cutting area and productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2114596B1A negative insert for cutting machining
Publication Date: 2013.02.27 SECO TOOLS AB
  • EP2114596B1 patent drawingFigure 1~6
  • EP2114596B1 patent drawingFigure 7~8

AI summary

A negative insert (1) f o r cutting machining h a s a top side (6), a clearance side (7) perpendicular thereto and a cutting edge (8) in a 5 region interconnecting these sides and extending substantially in p a r a l l e l with t h e s e sides. The insert has further a flat or rounded chamfer (10) connecting said cutting edge to said clearance side on at least one lateral side of the insert in the region of a corner thereof. The chamfer makes an angle of 1°-15° with the clearance side for 10 enabling application of the chamfer substantially tangentially to a w o r k piece (12) to be machined for bearing of the insert in two d i - m e n s i o n s against said work piece during cutting machining o p e r a t i o n carried out by the insert. ( F i g 5). 15