Cutting Insert Seat Structure for Higher Tool Body Stiffness

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Solution Overview

Problem

Cutting tools used for grooving in hole bottom surfaces face challenges with reduced ejection performance of chips and interference between the cutting material and the cutting insert, leading to damage of the cutting edge, particularly due to insufficient support stiffness, which results in chattering during machining.

Innovation Solution

The design includes an insert seat with a deep seat portion, a shallow seat portion, and rotation suppression portions to increase the thickness and stiffness of the cutting tool body without altering its size, featuring a deep seat portion with a surface perpendicular to the screw hole axis and a shallow seat portion that becomes shallower towards the base end, along with engagement projected parts and rotation suppression portions to enhance support stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the body is elongated to receive reaction force from the base end part of the cutting insert, then the deflection of the cutting edge is suppressed, but the body itself deflects due to insufficient support stiffness

Engineering Contradiction:
Improvedeflection suppression of cutting edgeVSAvoidsupport stiffness of body
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The insert seat is segmented into multiple functional portions: a deep seat portion for receiving the cutting insert, a shallow seat portion for providing support stiffness, and a rotation suppression portion for preventing insert rotation. This segmentation allows each portion to be optimized for its specific function, resolving the contradiction between deflection suppression and body stiffness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention addresses the deflection problem not by elongating the body in the axial direction, but by creating a shallow seat portion that extends radially outward from the deep seat portion. This dimensional change provides additional support stiffness without increasing the overall body length, thereby preventing body deflection while still suppressing cutting edge deflection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the depth of the seat portion is increased to improve reaction force reception, then the cutting insert is better supported, but the body thickness is reduced and stiffness is compromised

Engineering Contradiction:
Improvereaction force receptionVSAvoidbody stiffness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The insert seat is divided into a deep seat portion and a shallow seat portion. The deep seat portion (depth L1) provides adequate reaction force reception for the cutting insert, while the shallow seat portion (depth L2, where L2 < L1) provides additional support stiffness. This segmentation allows the system to achieve both reliable reaction force reception and sufficient body stiffness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the insert seat have different depths tailored to their specific functions. The deep seat portion has greater depth for receiving and supporting the cutting insert, while the shallow seat portion has lesser depth for maintaining body stiffness. This local differentiation of quality resolves the contradiction between reaction force reception and body stiffness.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4420813A1Body of cutting tool and cutting insert
Publication Date: 2024.08.28 TUNGALOY CORP
  • EP4420813A1 patent drawingFigure 1~2
  • EP4420813A1 patent drawingFigure 3~5
  • EP4420813A1 patent drawingFigure 6~7

AI summary

A body of a cutting tool and a cutting insert which can further improve support stiffness of the cutting insert are provided. A body of a cutting tool includes an insert seat provided on a leading end part of the body, a screw hole with which a fastening screw is screwed, a deep seat portion provided at a deep part in the insert seat in an axial direction of the screw hole, a receiving portion receiving a contact portion of the cutting insert, a wall portion having a base-end side rotation suppression portion which stops rotation of the cutting insert, and a shallow seat portion, the depth of a seat thereof being shallower than a part with the receiving portion, wherein the base-end side rotation suppression portion is positioned not to overlap the deep seat portion when viewed along a screw-hole axis.