Cutting Insert With Negative Axial Rake Angle For Impact Resistance

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Solution Overview

Problem

Existing cutting inserts with positive axial rake angles are prone to damage due to high contact impact during cutting processes, especially at high feed rates, as the peripheral surface end portions contact the workpiece first.

Innovation Solution

A cutting insert with a first cutting edge that is projected toward the upper surface in side view and recessed inward in top view, attached to a holder to achieve a negative axial rake angle, reducing contact angle and dispersing impact force, while allowing precise flattening of the target cutting surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a positive axial rake angle is used in the cutting insert, then the cutting edge can easily contact the workpiece, but the end portion of the peripheral surface cutting edge is prone to damage under high feed rate cutting conditions

Engineering Contradiction:

Improveease of contactVSAvoidimpact resistance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent inverts the conventional positive axial rake angle to a negative axial rake angle. This inversion changes the contact sequence during cutting, allowing the cutting edge to contact the workpiece in a way that prevents end portion damage while maintaining effective cutting engagement.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the axial rake angle parameter from positive to negative. This parameter change fundamentally alters the geometry of the cutting edge, enabling it to resist impact forces during high feed rate cutting while still achieving proper contact with the workpiece.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the first cutting edge is projected toward the upper surface in side view and recessed inward in top view, then impact force is dispersed and impact resistance is improved, but the structure becomes more complex

Engineering Contradiction:

Improveimpact resistanceVSAvoidcutting edge geometry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dimensional changes to the cutting edge geometry by projecting it toward the upper surface in side view and recessing it inward in top view. This multi-dimensional geometric configuration disperses impact forces across different spatial dimensions, improving impact resistance while managing structural complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8740518B2Insert, cutting tool, and method of manufacturing machined product using them

Publication Date: 2014.06.03 KYOCERA CORP

AI summary

An insert according to an embodiment of the present invention includes an upper surface, a lower surface, a side surface which is connected to the upper surface and the lower surface, and includes a first side surface, and a cutting edge which is located an intersection of the upper surface and the side surface, and comprises a first cutting edge corresponding to the first side surface. The first cutting edge has a projected shape projected toward the upper surface in a side view, and has a recessed shape recessed inward in a top view. A cutting tool according to an embodiment of the present invention includes the insert and a holder configured to attach the insert thereto so that at least a part of the first cutting edge has a negative axial rake angle. A method of manufacturing a machined product according to an embodiment of the present invention is a method of manufacturing the machined product by using the cutting tool.