Asymmetric Octagonal Cutting Insert for Multiple Finishing Edges

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Solution Overview

Problem

Conventional face milling cutters with wide finishing inserts can only utilize a single effective finishing cutting edge for a given direction of rotation, leading to inefficiencies and the need for frequent replacement due to wear, whereas they typically require multiple finishing cutting edges for optimal performance.

Innovation Solution

A cutting insert with an octagonal shape and alternating corner angles, featuring at least two diagonally opposed finishing cutting edges and six abutment surfaces, allowing for the use of multiple finishing cutting edges in the same insert seat as roughing inserts, with finishing edges extending at least 30% of the insert's diameter and differing profiles for roughing and finishing edges, enabling dual or quadruple the number of usable edges per rotation without altering the insert seat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a wide finishing insert with a single long finishing cutting edge is used, then the finishing surface quality is improved, but the number of usable finishing edges is limited to one per direction of rotation

Engineering Contradiction:
Improvefinishing surface qualityVSAvoidnumber of usable finishing edges
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The finishing insert is segmented into multiple discrete finishing cutting edges (at least two, preferably three or four) distributed around the insert periphery, rather than using a single long finishing edge. This segmentation allows multiple edges to be utilized in sequence during rotation, increasing productivity while each edge maintains the precision required for finishing work

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert employs asymmetric corner angle design with alternating small and large corner angles around the periphery. This asymmetry creates distinct finishing cutting edges at specific locations, allowing the insert to provide multiple finishing edges for one direction of rotation while maintaining the geometric precision needed for high-quality surface finishing

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If conventional roughing inserts with four-fold symmetry are used, then manufacturing simplicity is maintained, but the ability to provide multiple finishing edges for one direction of rotation is lost

Engineering Contradiction:
Improveinsert symmetry and standardizationVSAvoidnumber of finishing edges per rotation direction
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The insert deliberately breaks the conventional four-fold symmetry by implementing alternating small and large corner angles around the periphery. This asymmetric design creates specific geometric features that enable multiple finishing cutting edges to be positioned optimally for one direction of rotation, while still maintaining manufacturability through systematic geometric construction

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The insert is designed to perform multiple functions: it provides both roughing cutting edges (at least six abutment surfaces) and finishing cutting edges (at least two diagonally opposed) on the same insert body. This multi-functionality allows a single insert design to replace what would traditionally require separate roughing and finishing inserts, increasing versatility without sacrificing ease of manufacture

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP1859883B1Cutting insert with wiper, in particular for face milling
Publication Date: 2010.12.29 SANDVIK INTELLECTUAL PROPERTY AB
  • EP1859883B1 patent drawingFigure 1
  • EP1859883B1 patent drawingFigure 2
  • EP1859883B1 patent drawingFigure 3

AI summary

The present invention relates to a cutting insert (10), in particular for face milling cutters, having an upper and a lower surface (3) which are connected to one another by circumferential edge surfaces (4), wherein the cutting insert, in a plan view of the upper surface (3), has an approximately octagonal basic shape with alternating small and large corner angles, wherein cutting edges (1a, 1b, 1c, 1d; 2a, 2b, 2c, 2d) are formed between the corners (6, 7) at the transition of the circumferential surfaces (4) to the upper and/or lower surface (3), of which cutting edges a part (2a, 2b, 2c, 2d) for use as roughing cutting edges in a plan view runs slightly broken or curved over a relatively smaller radius and another part runs straight or curved with a relatively larger radius as finishing cutting edges (1a, 1b, 1c, 1d) between adjacent corners (6, 7).In order to create a cutting insert with the features mentioned at the outset, which can be used in the same way as a wide finishing insert, but nevertheless has at least two and preferably at least four finishing cutting edges that can be used for one direction of rotation, it is proposed according to the invention that in the plan view perpendicular to the surface the cutting insert is designed symmetrically only with respect to a rotation of 180° but not with respect to a rotation of 90°.