Tangential Milling Insert With Concave Support Surfaces

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Solution Overview

Problem

Existing tangential cutting inserts for milling tools face issues with uneven pressure distribution and reduced stability due to flat support surfaces, leading to deformation and premature wear, especially during high-load operations like cast iron milling.

Innovation Solution

The cutting insert features concave second support surfaces on its lateral surfaces, extending diagonally for both axial and tangential support, which improves pressure distribution and stability by allowing better contact with the pocket faces, and includes a rake surface for chip breaking to minimize wear on support surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flat support surfaces are used on the cutting insert, then the structure is simple and easy to manufacture, but the pressure distribution becomes uneven and stability is reduced

Engineering Contradiction:

Improveease of manufactureVSAvoidstability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies curvature by replacing flat support surfaces with concave support surfaces on the cutting insert. The concave surfaces are configured to match convex support faces on the tool holder, creating a curved interface that distributes cutting forces more evenly across the contact area. This curvature transformation resolves the contradiction by maintaining manufacturing feasibility while dramatically improving pressure distribution and insert stability during milling operations.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Device complexity

If flat support surfaces are used on the cutting insert, then the design is simple, but deformation of pocket support faces occurs under cutting forces

Engineering Contradiction:

Improvedevice complexityVSAvoidstrength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The concave support surfaces are specifically designed to complement the convex support faces of the tool holder, creating a curved contact interface. This curvature match increases the contact area and distributes cutting forces more uniformly, preventing localized stress concentrations that cause deformation of the pocket support faces. The solution maintains relative design simplicity while significantly enhancing the strength and rigidity of the insert-holder connection.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of manufacture

If flat support surfaces are used, then manufacturing is easier, but the mounting stability of the insert in the pocket is reduced

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The concave support surfaces on the insert are designed to mate with convex support faces on the tool holder, creating a curved interface that provides more reliable mounting. The curved geometry increases friction and mechanical interlocking between the insert and holder, preventing insert displacement or loosening during high-vibration milling operations. This curvature-based solution maintains manufacturing simplicity while dramatically improving mounting reliability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Volume of moving object

If support surfaces are positioned close to cutting edges, then structural compactness is achieved, but wear on support surfaces increases

Engineering Contradiction:

ImprovevolumeVSAvoidduration of action

Core Design Contradiction:

Volume of moving objectVSDuration of action of moving object

Solution Approach 1:

The patent applies segmentation by dividing the support surface into distinct functional zones: concave support surfaces for force distribution and flat or elevated surfaces for chip breaking. This segmentation allows the support surfaces to be positioned optimally for both structural compactness and wear protection. The chip breaking surfaces act as a protective barrier, preventing chips from directly contacting and wearing the concave support surfaces, thereby extending insert life while maintaining compact geometry.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces chip breaking surfaces as an intermediary element between the cutting edges and the support surfaces. These surfaces intercept and break chips before they can slide across and wear the support surfaces. This intermediary function protects the support surfaces from direct chip contact, reducing wear and extending the duration of action of the cutting insert while maintaining compact overall dimensions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3045246B1A cutting insert and a milling cutting tool

Publication Date: 2021.07.14 SANDVIK INTELLECTUAL PROPERTY AB

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AI summary

An indexable tangential cutting insert (4) for a milling tool comprises two opposing side surfaces (13) and four identical lateral surfaces (16, 17) extending between the side surfaces. Each lateral surface of the insert is provided with a support surface (32) configured to be supported by on one hand a corresponding support face of a pocket (3) of a tool body providing an axial support to the insert in two of eight index positions and on the other a corresponding support face of the pocket providing a tangential support to the insert in two other of said eight index positions. Each lateral surface (16, 17) of the insert is provided with a single said second support surface (32) being concave as seen in a direction perpendicular to said side surfaces and extending diagonally across the lateral surface.