Curved Milling Insert Geometry for Longer Tool Life

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Solution Overview

Problem

Milling inserts for side and face milling tools face challenges in achieving extended tool life and toughness when working with materials like stainless steel, titanium, and heat-resistant super alloys, while maintaining high-quality surface finishes and being cost-efficient.

Innovation Solution

The milling insert design features a main cutting edge that slopes downward and outward, with a concave shape in side view and convex shape in top view, along with a main radial clearance surface that can be ground in a single-pass operation, enhancing tool life and toughness by reducing cutting forces and angle errors, and allowing for precise manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a conventional milling insert with straight main cutting edge is used, then the manufacturing process is simple, but the tool life and toughness are insufficient when milling stainless steel, titanium and heat resistant super alloy materials

Engineering Contradiction:

Improvetool lifeVSAvoidcutting edge geometry complexity

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The main cutting edge is designed with a specific curvature profile featuring a rounded midpoint that slopes downward from corner cutting edges toward the midpoint. This curved geometry reduces cutting forces and improves chip flow, thereby extending tool life when milling difficult materials like stainless steel, titanium and heat resistant super alloys

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Different sections of the main cutting edge are given different geometric properties: the midpoint has a rounded profile with specific radius of curvature to reduce cutting forces, while the corner sections maintain sharpness for effective material removal. This localized optimization of cutting edge geometry improves both tool life and cutting performance

Inventive Principle:

Principle #3Local quality

2Duration of action of moving object

If the main cutting edge is designed with downward slope and outward convex shape, then cutting forces are reduced and tool life is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvetool lifeVSAvoidcutting edge geometry precision

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The cutting edge geometry is defined by specific parameters including the radius of curvature at the midpoint, the slope angle from corner to midpoint, and the outward convex profile characteristics. By optimizing these parameters, the design achieves reduced cutting forces and improved tool life while maintaining manufacturability through precise control of geometric parameters

Inventive Principle:

Principle #35Parameter changes

3Productivity

If multiple grinding operations are required for the main radial clearance surface, then manufacturing flexibility is increased, but production time and cost increase

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The main radial clearance surface is designed with a uniform slope from the upper side to the lower side, allowing both surfaces to be ground in a single-pass operation. This merging of manufacturing steps reduces production time and cost while maintaining the required clearance geometry for proper insert function

Inventive Principle:

Principle #5Merging (Combining)

4Duration of action of moving object

If the milling insert is designed for high toughness and extended tool life, then performance in difficult materials is improved, but the surface quality of machined parts may be compromised

Engineering Contradiction:

Improvetool lifeVSAvoidsurface quality

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The cutting edge geometry is optimized locally with a rounded midpoint profile that reduces cutting forces and improves chip flow for extended tool life, while the corner sections maintain sharpness for precise material removal and good surface quality. This localized optimization achieves both toughness and surface quality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The curved profile of the main cutting edge with specific radius of curvature at the midpoint reduces cutting forces and improves chip evacuation, thereby extending tool life while maintaining surface quality through smoother cutting action and reduced vibration

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS11612942B2Milling insert and a side and face milling tool

Publication Date: 2023.03.28 SANDVIK INTELLECTUAL PROPERTY AB

AI summary

A milling insert for a side and face milling tool includes an upper side defining an upper extension plane, a lower side defining a lower extension plane, and a side surface extending between the upper and the lower sides around a periphery of the insert that includes a main radial clearance surface, two opposite axial clearance surfaces and two corner clearance surfaces. At least one cutting edge is formed in a transition between the upper and the side surfaces, wherein each cutting edge includes a main cutting edge extending above the main radial clearance surface and two corner cutting edges extending above the corner clearance surfaces on opposite sides of the main cutting edge. The main cutting edge slopes downward toward a midpoint of the main cutting edge and the main cutting edge and the main radial clearance surface slope outward from the corner cutting edges toward the midpoint.