End Mill Peripheral Flank Design for Surface Flatness

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Solution Overview

Problem

Conventional end mills experience elastic deformation and undulation during cutting work, leading to accuracy defects in high-precision flatness and straightness due to tool abrasion and varying cutting edge contact points, which worsens with progressive tool wear.

Innovation Solution

The end mill design features a combination of first and second peripheral flanks with different clearance angles, where the second flank, with a larger angle, is strategically formed to accelerate abrasion in areas corresponding to recess portions on the worked surface, offsetting undulation and maintaining tool diameter, thereby reducing undulation height and enhancing surface flatness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional end mill with uniform peripheral flanks is used, then the tool can maintain its diameter during cutting, but tool abrasion causes increasing undulation height on the worked surface over time

Engineering Contradiction:

Improveflatness of worked surfaceVSAvoidservice life of end mill

Core Design Contradiction:

Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

The end mill applies local quality by creating a recess portion in the peripheral flank at a specific location corresponding to the rotation phase where maximum undulation occurs. This localized modification causes accelerated abrasion only in that specific area, allowing the tool diameter to reduce selectively to compensate for undulation without affecting other parts of the cutting edge.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention converts the harmful effect of tool abrasion into a beneficial self-rectifying mechanism. By strategically positioning the recess portion, the natural wear process becomes a corrective action that reduces undulation height over time, transforming wear from a degradation mechanism into a surface quality improvement mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If the end mill rotates at high speed, then productivity increases, but elastic deformation varies during rotation causing undulation on the worked surface

Engineering Contradiction:

Improvecutting speedVSAvoidstraightness of worked surface

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The recess portion is pre-formed in the peripheral flank at the specific rotation phase position where maximum undulation is predicted to occur. This preliminary action prepares the tool to self-correct undulation as it rotates, allowing high-speed cutting to proceed while the wear pattern naturally compensates for elastic deformation effects.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the peripheral cutting edges are separated in the axial direction, then the tool can remove material from side and bottom surfaces simultaneously, but the number and location of cutting points varies causing varying deflection

Engineering Contradiction:

Improvemulti-surface cutting capabilityVSAvoidflatness of worked surface

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The recess portion is positioned at a specific axial location on the peripheral flank corresponding to where cutting edges contact the workpiece during rotation. This localized modification creates a selective wear pattern that compensates for the varying deflection caused by multiple cutting points, maintaining surface flatness despite the versatile multi-surface cutting capability.

Inventive Principle:

Principle #3Local quality

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 design reduces undulation height and maintains working accuracy over time, improving the precision and appearance of cut surfaces, and extends the service life of end mills by self-rectifying surface irregularities and preventing excessive material removal.

Implementation Method 1

the second peripheral flank formed in an area of a rear side on the first peripheral flank in the rotating direction and formed in a position of a rotation phase being common to each of the peripheral cutting edge portions

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS10118237B2End mill and scroll for scroll compressor

Publication Date: 2018.11.06 MITSUBISHI ELECTRIC CORP

AI summary

In an end mill, a peripheral cutting edge portion has a peripheral cutting edge formed in a spiral shape around an axis, a peripheral rake face formed on the front side of the peripheral cutting edge in the rotating direction and bordering thereon and a peripheral flank formed on the rear side of the peripheral cutting edge in the rotating direction and bordering thereon. The peripheral flank has a first peripheral flank formed in a position on the mill body tip side to have a first clearance angle and a second peripheral flank formed in a position on the mill body end side of the first peripheral flank and neighboring the first peripheral flank to have a second clearance angle. An average width value of the first peripheral flank in the rotating direction is greater than an average width value of the second peripheral flank in the rotating direction.