Brazed Cutting Insert Structure to Suppress Gaps Between Pieces

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Solution Overview

Problem

Conventional cutting tools experience gaps between hard sintered material pieces due to surface tension of brazing materials during the brazing process, leading to inefficiencies in material usage and increased processing costs.

Innovation Solution

A cutting insert design featuring a substrate with a polygonal top surface and a projection with a through-hole, where the cutting-edge insert is divided into pieces with protrusions that annularly surround the projection, reducing the likelihood of gaps and optimizing material usage by displacing centers of gravity from vertices, thereby minimizing raw material requirements and processing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiple hard sintered material pieces are joined to the core using brazing, then the cutting tool can be assembled with modular components, but surface tension of the brazing material causes gaps between the pieces

Engineering Contradiction:
Improvemodular assemblyVSAvoidgap between pieces
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary anti-action by designing protrusions on the hard sintered material pieces that prevent gap formation before the brazing process completes. The protrusions physically constrain the pieces against lateral displacement that would otherwise be caused by surface tension forces during brazing, thereby preventing the harmful effect before it can occur.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent employs asymmetry by giving each hard sintered material piece an asymmetric shape with protrusions that interlock with adjacent pieces. This asymmetric geometry prevents lateral displacement and gap formation during brazing, while the asymmetric centers of gravity positioned away from vertices provide stable positioning during the assembly process.

Inventive Principle:
Principle #4Asymmetry

2Loss of substance

If the cutting-edge insert is divided into multiple pieces, then material usage can be optimized and processing costs reduced, but gaps may form between the divided pieces during brazing

Engineering Contradiction:
Improveraw material usageVSAvoidgap between divided pieces
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the cutting-edge insert into multiple hard sintered material pieces (first, second, third, and fourth pieces) that can be separately manufactured and then assembled. This segmentation allows for optimized material usage and reduced processing costs while maintaining cutting performance through the interlocking protrusion design that prevents gap formation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nesting-like structure where protrusions on each hard sintered material piece fit into spaces between adjacent pieces, creating an interlocking arrangement. This nested configuration ensures tight fitting and prevents gap formation during brazing, while allowing the divided pieces to be manufactured separately for material optimization.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If the centers of gravity of the divided pieces are positioned at the vertices, then the structure is symmetric and simple, but gap formation is more likely during brazing

Engineering Contradiction:
Improvestructural symmetryVSAvoidgap suppression
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent deliberately introduces asymmetry by positioning the centers of gravity of the hard sintered material pieces away from the vertices of the polygonal configuration. This asymmetric positioning, combined with the protrusion design, creates interlocking effects that suppress gap formation during brazing, while the overall structure remains manageable through the regular polygonal arrangement of the pieces.

Inventive Principle:
Principle #4Asymmetry

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design effectively suppresses gap formation between divided pieces, reduces raw material usage, and increases the utilization of cutting-edge portions, resulting in cost-effective manufacturing and improved productivity.

Implementation Method 1

The cutting-edge insert is brazed to the top surface and the side surface so as to annularly surround the projection.

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP4169663B1Cutting insert and method of manufacturing cutting insert
Publication Date: 2024.06.05 SUMITOMO ELECTRIC HARDMETAL CORP
  • EP4169663B1 patent drawingFigure 1
  • EP4169663B1 patent drawingFigure 2
  • EP4169663B1 patent drawingFigure 3

AI summary

A cutting insert includes a substrate and a cutting-edge insert. The substrate has, in a thickness direction of the substrate, a bottom surface, and a top surface opposite to the bottom surface. The top surface has a polygonal shape composed of a plurality of sides in a plan view as seen along the thickness direction. The top surface is provided with a projection projecting to a side opposite to the bottom surface along the thickness direction. The projection has a through-hole passing through the substrate along the thickness direction. The projection has a side surface contiguous to the top surface. The side surface is composed of a curved line protruding to a side opposite to the through-hole in the plan view as seen along the thickness direction. The curved line includes a plurality of vertices at positions at which the curved line has a minimum distance from the plurality of sides, respectively. The cutting-edge insert is brazed to the top surface and the side surface so as to annularly surround the projection.