Reversible Milling Insert With Variable Minor Relief Width

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Solution Overview

Problem

Existing rotary cutting tools for milling operations lack improved surface finish, robust cutting edges, and efficient performance in square shoulder milling operations, particularly in achieving a compact minor relief surface and long minor cutting edge configuration.

Innovation Solution

A reversible cutting insert with opposing end surfaces interconnected by a continuous peripheral surface, featuring three side surfaces and three corner surfaces, with major and minor cutting edges, and varying minor relief width that exceeds the maximum minor relief width, allowing for enhanced machining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the minor relief surface has a constant width as in prior art, then the structure is simple, but the surface finish of the workpiece is not improved and the minor cutting edge cannot be sufficiently extended

Engineering Contradiction:
Improvesurface finishVSAvoidminor relief surface geometry
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The minor relief surface transitions from a uniform constant width to a variable width configuration, where the width changes along the length of the surface. This local variation in geometry allows different sections of the minor cutting edge to have optimized relief characteristics, improving surface finish without requiring complete redesign of the entire relief surface structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameter of the minor relief surface from constant width to variable width. This parameter change enables the minor cutting edge to extend further while maintaining appropriate relief angles, directly addressing the limitation of prior art where the constant width constrained the effective length of the minor cutting edge

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the minor cutting edge is extended to improve surface finish, then the surface quality improves, but the minor relief surface becomes larger and less compact

Engineering Contradiction:
Improvesurface finishVSAvoidminor relief surface size
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

By implementing variable width rather than uniform extension, the relief surface concentrates its material distribution where needed. The width varies along the length, providing sufficient relief where required while minimizing unnecessary material, thus extending the functional length without proportionally increasing the overall volume

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The variable width configuration creates a more streamlined, compact form compared to a simple linear extension. The geometry tapers or varies in a controlled manner, reducing the overall envelope volume while maintaining the extended functional length of the minor cutting edge

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the cutting insert has robust cutting edges, then the tool durability improves, but the cutting forces and stress concentrations increase

Engineering Contradiction:
Improvetool durabilityVSAvoidcutting forces
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The variable width relief surface creates localized variations in relief geometry that optimize the distribution of cutting forces. By having different relief widths at different locations, the design provides enhanced support where stress concentrations occur while maintaining reduced overall cutting forces through optimized relief angles in other sections

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2998053B1Rotary cutting tool and reversible cutting insert having variable-width minor relief surfaces therefor
Publication Date: 2022.02.23 ISCAR LTD
  • EP2998053B1 patent drawingFigure 1~2a
  • EP2998053B1 patent drawingFigure 2b~3a
  • EP2998053B1 patent drawingFigure 3b~4

AI summary

In a rotary cutting tool (52) used for milling operations, a reversible cutting insert (20) is removably secured in a cutting body (54). The cutting insert (20) has two opposing end surfaces (22) interconnected by a continuous peripheral surface (24), which includes three side surfaces (26) alternating with three comer surfaces (28). The side and comer surfaces (26, 28) intersect with both end surfaces (22) at side and comer edges (32, 34), respectively, with each side edge (32) having a major cutting edge (36), and each comer edge (34) having a comer and minor cutting edge (38, 40). Each minor cutting edge (40) has a projected minor cutting length (LM), in an end view, and each associated minor relief surface (48) has a minor relief width (W) between two lateral boundary points contained in a horizontal plane (PH), varying with an offset distance (DO) between the horizontal plane (PH) and a median plane (M). Each projected minor cutting length (LM) is greater than the maximum minor relief width (WMAX) of its associated minor relief surface (48).