Boring Tool Coolant Layout for Blind-Hole Chip Discharge

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Solution Overview

Problem

Existing boring tools face issues with chip clogging and cutting blade wear during inner face machining of blind holes due to coolant blocking the chip discharge flow, especially in small-diameter holes with limited space.

Innovation Solution

The implementation of a dual coolant discharge system with a first discharge hole at the tool body's leading end face and a second discharge hole on its outer circumference, allowing coolant to flow towards the hole bottom and cutting edge, respectively, along with an adjusting mechanism to optimize coolant flow rates, minimizes chip accumulation and blade wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If coolant is jetted toward the cutting blade through a single discharge hole, then the cutting blade is cooled and chip adhesion is prevented, but chip discharge is blocked and chip accumulation occurs at the hole bottom

Engineering Contradiction:
Improvecutting blade temperatureVSAvoidchip accumulation
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The single coolant discharge hole is divided into two separate discharge holes: a first discharge hole for directing coolant toward the hole bottom to flush chips outward, and a second discharge hole for jetting coolant toward the cutting blade to cool it and prevent chip adhesion. This segmentation allows the coolant flow to perform both chip discharge and cooling functions simultaneously without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tool body are provided with different discharge holes having specific functions: the first discharge hole (positioned to direct coolant toward the hole bottom) handles chip discharge, while the second discharge hole (positioned to direct coolant toward the cutting blade) handles cooling. Each discharge hole is optimized for its specific local function, achieving both chip discharge and cooling effectiveness.

Inventive Principle:
Principle #3Local quality

2Temperature

If coolant flow rate is increased to improve cooling effect, then cutting blade temperature is reduced, but chip discharge capability is compromised due to coolant blocking chip flow

Engineering Contradiction:
Improvecutting blade temperatureVSAvoidchip discharge efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The coolant flow is segmented into two separate streams through two discharge holes: one stream (from the first discharge hole) is optimized for chip discharge by directing it toward the hole bottom, while the other stream (from the second discharge hole) is optimized for cooling by directing it toward the cutting blade. This allows both functions to operate at optimal flow rates simultaneously.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If a single discharge hole is used for both chip discharge and cooling, then device complexity is reduced, but both chip discharge and cooling effects cannot be optimized simultaneously

Engineering Contradiction:
Improvecoolant discharge system complexityVSAvoidmachining process reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coolant discharge system is segmented into two discharge holes with distinct functions: the first discharge hole for chip discharge and the second discharge hole for cooling. Although this increases the number of components, it significantly improves machining reliability by ensuring both chip discharge and cooling functions operate effectively without interfering with each other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system provides dynamic adaptability through adjusting mechanisms that allow independent control of coolant flow rates through each discharge hole. This enables the system to adapt to different machining conditions (blind holes, through holes, varying chip loads) while maintaining both chip discharge and cooling effectiveness, thereby improving overall process reliability.

Inventive Principle:
Principle #15Dynamics

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

This configuration enhances chip discharge and cutting edge cooling, effectively preventing chip accumulation and reducing cutting blade wear, while allowing for adjustable coolant flow to suit varying machining conditions without complex internal machining.

Implementation Method 1

the coolant discharged from the first discharge hole will form a flow which is reflected at/by the hole bottom to then rise along the inner wall of the hole toward the opening

Methodology Applied
Scientific EffectFluid flow reflection and rise along inner wall: Convection

Implementation Method 2

the coolant discharged from the second discharge hole toward the cutting edge will cool the cutting edge, thus effectively preventing adhesion of chips to this cutting edge

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3141325B1Boring tool
Publication Date: 2021.04.14 DAISHOWA SEIKI CO LTD
  • EP3141325B1 patent drawingFigure 1~2
  • EP3141325B1 patent drawingFigure 3~4
  • EP3141325B1 patent drawingFigure 5~6

AI summary

Provided is a boring tool capable of suppressing wear of a cutting blade according to a shape of a bore to be formed in a workpiece. The tool includes a tool body (2) to be attached to a spindle of a rotary machining tool, and a plurality of cartridges (3) each attached to a leading end face of the tool body (2), having a cutting blade (5) and being position-adjustable in a radial direction. The tool body (2) has a coolant passage (24) for transporting coolant along a rotational axis direction. A discharge hole for the coolant is comprised of a first discharge hole (25) provided between the plurality of cartridges (3) in a leading end face (7) and a second discharge hole (26) provided in an outer circumference of the tool body (2) and directed toward the cutting edge of the cutting blade (5).