Boring Tool U-Shaped Groove and Carbide Edge Rigidity

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Solution Overview

Problem

Conventional reamers face issues with rigidity loss due to chip discharging groove design, thermal expansion mismatch between cemented carbide and steel components, and inadequate coolant supply, leading to inaccurate hole formation and increased manufacturing costs.

Innovation Solution

A boring tool with a U-shaped chip discharging groove, a cemented carbide edge part harder than the shank part, and separate sintering of shank and edge parts to ensure optimal coolant supply and reduced thermal distortion, along with a back tapered design to enhance rigidity and prevent breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If chip discharging grooves are formed on the edge part, then chip discharge is improved, but rigidity of the edge part deteriorates

Engineering Contradiction:

Improvechip dischargeVSAvoidrigidity of edge part

Core Design Contradiction:

Object-generated harmful factorsVSStrength

Solution Approach 1:

The edge part is divided into multiple functional zones: a cutting edge portion with chip discharging grooves for effective chip removal, and a land portion without grooves that maintains rigidity and provides stable support during cutting operations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the edge part are given different properties: the cutting edge portion has grooves optimized for chip discharge, while the land portion maintains solid structure for rigidity, creating local optimization of both chip removal and structural strength

Inventive Principle:

Principle #3Local quality

2Productivity

If cemented carbide edge part is used, then cutting performance is improved, but thermal expansion mismatch with steel shank part causes distortion

Engineering Contradiction:

Improvecutting performanceVSAvoidhole formation accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

A transition portion is introduced between the cemented carbide edge part and steel shank part, serving as a thermal and mechanical buffer that accommodates differential thermal expansion and reduces distortion during cooling after sintering

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The boring tool uses a composite structure combining cemented carbide edge part with steel shank part, leveraging the high hardness and wear resistance of cemented carbide while using steel's toughness and thermal properties to compensate for thermal expansion issues

Inventive Principle:

Principle #40Composite materials

3Reliability

If edge part length is increased, then cutting edge contact area is improved, but rigidity and breakage resistance deteriorate

Engineering Contradiction:

Improvecutting edge contact areaVSAvoidbreakage resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The edge part length is segmented into functional portions: a cutting edge portion with adequate length for sufficient contact area and cutting performance, and a land portion that provides structural support and rigidity, preventing the entire edge part from being excessively long and vulnerable to breakage

Inventive Principle:

Principle #1Segmentation

4Temperature

If coolant supply is enhanced, then cutting temperature is reduced, but device complexity increases

Engineering Contradiction:

Improvecutting temperatureVSAvoidcoolant supply structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The boring tool integrates coolant supply ports directly into the edge part structure, allowing coolant to be delivered self-contained through the tool itself without requiring external cooling systems or complex auxiliary devices

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The coolant supply function is merged with the edge part structure by forming coolant supply ports within the edge part, combining the cutting tool and cooling system into a single integrated component

Inventive Principle:

Principle #5Merging (Combining)

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 solution provides improved rigidity and accuracy in hole formation, reduces breakage risk, and allows for efficient coolant delivery, resulting in longer tool life and lower manufacturing costs.

Implementation Method 1

thermal expansion mismatch between cemented carbide and steel components

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

separate sintering of shank and edge parts

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 3

efficient coolant delivery

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS8272815B2Boring tool and method of boring pilot hole

Publication Date: 2012.09.25 MITSUBISHI MATERIALS CORP

AI summary

A boring tool can form a hole accurately by improving the rigidity of a reamer so that the runout of the reamer can be prevented at high speeds, extending product life by suppressing the breakage caused by cutting resistance. The boring tool is inserted into a pilot hole formed in a workpiece beforehand to cut the inner wall of the pilot hole. The boring tool comprises a shank part rotated about an axis, an edge part with a cutting edge at the tip of the shank part, and a chip discharging groove formed in the outer peripheral part of the edge part and extending from the tip to the rear end. The cutting edge is formed at a crossed ridge part between the wall surface of the chip discharging groove and the outer peripheral surface of the edge part. The cross-section of the chip discharging groove is formed in a U-shape.