Eccentric Cutting Insert Mounting for Narrow Slot Milling

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Solution Overview

Problem

Existing rotary cutting tools face challenges in achieving precise slotting with indexable cutting inserts, particularly in producing slots with reduced width relative to the insert cutting width, due to limitations in lateral and axial support mechanisms.

Innovation Solution

A cutting tool design featuring a tool body with insert receiving pockets that utilize spherical engagement elements and stress relief grooves, allowing for indexable double-sided cutting inserts with eccentric contact, which provides enhanced stability and reduces the need for additional support walls, enabling the production of narrower slots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional insert mounting mechanisms are used, then the insert can be retained in the tool body, but lateral stability and positioning precision are insufficient

Engineering Contradiction:
Improvelateral stabilityVSAvoidpositioning precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs spherical engagement elements (balls) that fit into corresponding spherical recesses on the cutting insert. This spherical interface provides superior lateral stability and positioning precision compared to traditional flat or V-shaped surfaces, as the ball-and-socket geometry naturally constrains movement in all lateral directions while maintaining precise angular orientation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent uses eccentric mounting where the spherical engagement elements are positioned offset from the insert's central axis. This asymmetric arrangement creates different support conditions on opposite sides of the insert, enabling precise control over the insert's lateral position and orientation relative to the tool body, thereby improving both stability and positioning accuracy.

Inventive Principle:
Principle #4Asymmetry

2Stability of the object's composition

If support walls are added to enhance insert stability, then lateral support improves, but the slot width increases

Engineering Contradiction:
Improveinsert stabilityVSAvoidslot width
Core Design Contradiction:
Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The spherical engagement elements provide three-point contact geometry that inherently stabilizes the insert laterally without requiring additional support walls. The ball-and-socket interface creates natural mechanical constraints that prevent lateral displacement while occupying minimal space, thus maintaining narrow slot widths while ensuring insert stability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent removes the need for traditional support walls by extracting the stabilizing function into the spherical engagement mechanism. Instead of using extended structural elements (support walls) to provide lateral stability, the invention concentrates the stabilizing function into compact spherical elements, thereby reducing the overall slot width required.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If multiple engagement points are used to improve positioning, then stability increases, but the mounting mechanism becomes more complex

Engineering Contradiction:
Improvepositioning stabilityVSAvoidmounting mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines multiple engagement functions into a single spherical interface. The ball-and-socket connection simultaneously provides lateral positioning, angular orientation, and rotational indexing in one integrated mechanism, eliminating the need for separate engagement features for each function and thereby reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spherical engagement elements serve multiple functions: they provide lateral support, define insert orientation, enable precise positioning, and allow for easy indexable rotation. This multi-functional design achieves high positioning stability without requiring separate dedicated features for each function, keeping the mounting mechanism relatively simple.

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

Data Source

PatentEP3774144B1Cutting tool and cutting insert having complementary engagement features for eccentric mounting
Publication Date: 2024.02.07 ISCAR LTD
  • EP3774144B1 patent drawingFigure 1~2
  • EP3774144B1 patent drawingFigure 3~4
  • EP3774144B1 patent drawingFigure 5~6

AI summary

A cutting tool (20) has a tool body (22) with a first insert pocket (24) and an indexable cutting insert (26) removably mounted therein. The first insert pocket has a first seat surface with a plurality of first engagement elements and a first support wall transverse thereto. The cutting insert has upper and lower surfaces and a boundary surface extending therebetween. The lower surface has a plurality of lower engaging elements and the boundary surface has a plurality of alternating first and second peripheral surfaces intersecting the upper surface to form first and second upper cutting edges. In each index position with the lower surface in contact with the first seat surface, the first support wall prevents translation of the cutting insert in a first direction, and the first engagement elements eccentrically contact the lower engaging elements to prevent translation of the cutting insert in a second direction perpendicular to the first direction.