Variable Lead End Mill Chip Discharge Flute Design

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Solution Overview

Problem

Variable lead end mills face challenges in efficiently discharging bulky chips due to varying cutting edge intervals, leading to increased cutting loads and potential damage, as existing solutions either clog or catch chips, compromising rigidity and strength.

Innovation Solution

The end mill features chip discharge flutes with a concavely curved main flute portion and a sub-flute portion with a linear flute bottom face, ensuring a larger cross-sectional area for smooth chip flow and preventing clogging, while the sub-flute portion's linear shape and increased intersection angle prevent chip catching, enhancing rigidity and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cutting edge interval is increased to reduce vibrations, then the cutting load increases and chip discharge becomes difficult, but if the cutting edge interval is decreased to improve chip discharge, then vibrations increase

Engineering Contradiction:
Improvevibration preventionVSAvoidchip discharge efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The chip discharge flute is divided into two distinct portions: a first portion with a convexly curved flute bottom face for receiving and transporting chips, and a second portion with a linearly shaped flute bottom face for efficient chip discharge. This segmentation allows each portion to optimize for its specific function, preventing both vibration and discharge issues simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single curved flute bottom face design to a two-dimensional configuration combining convex and linear sections. The linearly shaped flute bottom face in the second portion creates a more effective chip discharge path by utilizing dimensional variation to guide chips smoothly out of the flute, resolving the contradiction between vibration prevention and chip discharge efficiency

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the flute bottom face is convexly curved to increase flute capacity, then chip discharge becomes inefficient, but if the flute bottom face is linearly shaped to improve chip discharge, then flute capacity decreases

Engineering Contradiction:
Improvechip storage capacityVSAvoidchip discharge efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The flute is segmented into two functional zones: the first portion with convexly curved flute bottom face that provides chip storage capacity, and the second portion with linearly shaped flute bottom face that ensures efficient chip discharge. This segmentation resolves the contradiction by assigning different geometric characteristics to different functional requirements within the same flute structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the flute bottom face are given different geometric qualities: the first portion has a convexly curved shape optimized for chip reception and storage, while the second portion has a linear shape optimized for chip discharge. This local differentiation of geometric properties allows each section to perform its specific function optimally without compromising the other

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2100683B1End mill
Publication Date: 2013.01.16 MITSUBISHI MATERIALS CORP
  • EP2100683B1 patent drawingFigure 1
  • EP2100683B1 patent drawingFigure 2~3
  • EP2100683B1 patent drawingFigure 4

AI summary

[Object] The object of this invention is to provide a variable lead end mill in which; a cutting edge has sufficient rigidity and strength thus preventing occurrence of damages, and an enhanced and reliable performance for discharging large amounts of bulky chips generated by the cutting edge is made possible. [Solution] A plurality of chip discharge flutes 4 are located on an outer periphery of a tip portion of the end mill body 1 which rotates on its axis O. Helix angle[s] between the axis and the cutting edge[s] 6 in the chip discharge flute[s] 4, of which is [are] at least one or more; is [are] different from others. A cross-section perpendicular to the axis shows that a flute bottom face 13 in a main flute portion 10 forms a concavely curved shape from the rake face 5 to a point where the flute bottom face, touches a web thickness circle C of the end mill body, forms a linear shape, and goes toward the end mill rotating direction; and a flute bottom face 14 in a sub-ffute portion 11 forms a linear shape, intersects with the flute bottom face 13 in the main flute portion 10 at an obtuse angle, goes further toward the end mill rotating direction T.