Double-Sided Cutting Insert with Asymmetric Edge Geometry

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Solution Overview

Problem

Existing cutting inserts for milling tools, particularly shoulder milling cutters, face challenges in efficiently machining 90° corners with high surface quality while protecting inactive cutting edges from wear and damage, especially when the number of cutting edges increases, making it difficult to maintain effective clearance angles during rotation.

Innovation Solution

A double-sided cutting insert with a plate-shaped base body featuring alternating main and plane cutting edges connected by rounded corners, designed for 4-fold rotational symmetry, where the cutting edges have varying distances from a reference plane to optimize the use of cutting edges and protect inactive edges through differential inclination, allowing for efficient machining of 90° shoulders with precise surface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of cutting edges on a cutting insert is increased to improve utilization, then the total number of usable cutting edges increases, but it becomes more difficult to protect inactive cutting edges from wear and damage

Engineering Contradiction:
Improveutilization of cutting insertVSAvoidprotection of inactive cutting edges
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cutting insert employs asymmetric positioning of cutting edges relative to the tilt axis. By arranging cutting edges at different radial distances from the tilt axis, the geometry ensures that when the insert is tilted to protect inactive edges, the asymmetric configuration naturally provides better protection for edges farther from the axis while maintaining cutting effectiveness for active edges. This asymmetric layout allows 8 cutting edges to be effectively utilized while improving protection of inactive edges during machining operations.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the cutting insert is tilted to protect inactive cutting edges, then protection against wear is improved, but it becomes difficult to maintain effective clearance angles in every indexing position

Engineering Contradiction:
Improveprotection of cutting edgesVSAvoidclearance angles
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The cutting insert features locally optimized geometry where different regions have different radial distances from the tilt axis. Each cutting edge is positioned at a specific radial distance tailored to its function: edges closer to the axis maintain better clearance angles during cutting, while edges farther from the axis receive enhanced protection when inactive. This local differentiation of geometric properties allows simultaneous achievement of edge protection and clearance angle maintenance across multiple indexing positions.

Inventive Principle:
Principle #3Local quality

3Reliability

If the cutting insert is tilted forward in the axial direction to protect the cutting edge located behind the plane cutting edge, then wear protection is improved, but the complexity of the insert geometry increases

Engineering Contradiction:
Improveprotection of cutting edgesVSAvoidinsert geometry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the tilt protection function with the overall cutting insert geometry by integrating the tilt axis alignment into the natural positioning of cutting edges. Rather than adding separate protection mechanisms, the geometry itself provides protection through the radial distance distribution of cutting edges from the tilt axis. This unified approach combines cutting functionality and protection functionality into a single geometric configuration, reducing overall system complexity while achieving edge protection.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3188866B1Double-sided cutting insert and milling tool
Publication Date: 2018.12.12 CERATIZIT AUSTRIA GES
  • EP3188866B1 patent drawingFigure 1
  • EP3188866B1 patent drawingFigure 2
  • EP3188866B1 patent drawingFigure 3

AI summary

The invention relates to a double-sided cutting insert (10) for milling, comprising an upper face (11), a lower face (12), and a circumferential lateral surface (13). A first (14) or a second cutting edge (15) is formed at the transition from the upper (11) or lower face (12) to the lateral surface (13). The cutting insert has a fourfold rotational symmetry with respect to an axis of symmetry (Z), and a reference plane (XY) running perpendicular to the axis of symmetry. The first cutting edge (14) and the second cutting edge (15) each have four cutting edge segments (20, 20', 20", 20"'), wherein the cutting edge segments each consist of a main cutting edge (21, 21', 21", 21"') and a face cutting edge (22, 22', 22", 22"') which are connected to each other via an associated rounded cutting corner (23, 23', 23", 23"'). The first and second cutting edges (14, 15) each have the greatest distance from the reference plane (XY) in the region of the cutting corners (23, 23', 23", 23"'). In the circumferential lateral surface, main free surfaces (24, 24', 24", 24"') or face free surfaces (25, 25', 25", 25"') are formed directly contacting an assigned main cutting edge or face cutting edge, wherein the exterior angles (ρ) formed between the main free surfaces and the reference plane are greater than the exterior angles (σ) formed between the face free surfaces and the reference plane.