Miniature Internal Boring Tool Balancing Rigidity and Chip Evacuation

Solution Overview

Problem

Miniature internal boring tools with outer cutting diameters less than 9 mm face challenges in balancing rigidity and chip evacuation, particularly due to limited space for chip removal and reduced constructional strength.

Innovation Solution

The development of a miniature internal boring tool with two to four integrally formed outwardly extending teeth, which provides increased tool life by maintaining a balance between material strength and chip evacuation space, while ensuring precise positioning of the cutting edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the number of teeth is increased to extend tool life, then tool life is improved, but chip evacuation space is reduced and constructional strength decreases

Engineering Contradiction:

Improvetool lifeVSAvoidconstructional strength

Core Design Contradiction:

Duration of action of moving objectVSStrength

Solution Approach 1:

The cutting portion is segmented into multiple teeth (two to four) distributed around the circumference, allowing the tool to maintain cutting capability while managing chip evacuation and structural integrity. Each tooth acts as an independent cutting element, and the segmentation enables better distribution of mechanical loads.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the cutting portion have optimized local characteristics: the teeth are positioned and sized to provide adequate cutting edges while maintaining sufficient spacing for chip evacuation. The neck portion dimensions are specifically optimized to balance structural strength with the need to accommodate multiple teeth and maintain rigidity.

Inventive Principle:

Principle #3Local quality

2Duration of action of moving object

If the number of teeth is increased to extend tool life, then tool life is improved, but chip evacuation space is reduced

Engineering Contradiction:

Improvetool lifeVSAvoidchip evacuation difficulty

Core Design Contradiction:

Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The cutting portion is segmented into multiple teeth (two to four) distributed around the circumference, allowing the tool to maintain cutting capability while managing chip evacuation and structural integrity. Each tooth acts as an independent cutting element, and the segmentation enables better distribution of mechanical loads.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The number of teeth is limited to two to four rather than maximizing the number, representing a partial action approach where the optimal number balances tool life extension with adequate chip evacuation space, rather than using excessive teeth that would completely block chip flow.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If the outer cutting diameter is reduced to achieve miniature size, then adaptability to small bores is improved, but constructional strength and rigidity deteriorate

Engineering Contradiction:

Improveadaptability to small boresVSAvoidconstructional strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

Different regions of the cutting portion have optimized local characteristics: the teeth are positioned and sized to provide adequate cutting edges while maintaining sufficient spacing for chip evacuation. The neck portion dimensions are specifically optimized to balance structural strength with the need to accommodate multiple teeth and maintain rigidity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The tool is made from solid carbide material, which provides exceptional strength-to-size ratio, enabling the miniature dimensions while maintaining sufficient constructional strength and rigidity for effective cutting operation in small bores.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250073789A1Miniature internal boring tool

Publication Date: 2025.03.06 ISCAR LTD

AI summary

A miniature internal boring tool including two to four shank flat surfaces and two to four integrally formed teeth. The outermost points of cutting edges of the teeth define an outer cutting diameter (OD) fulfilling the condition: 2 mm<OD<9 mm.